/* Handle SVR4 shared libraries for GDB, the GNU Debugger.
- Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
- 2001, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1990-2019 Free Software Foundation, Inc.
This file is part of GDB.
#include "gdbcore.h"
#include "target.h"
#include "inferior.h"
-
-#include "gdb_assert.h"
+#include "infrun.h"
+#include "regcache.h"
+#include "gdbthread.h"
+#include "observable.h"
#include "solist.h"
#include "solib.h"
#include "elf-bfd.h"
#include "exec.h"
#include "auxv.h"
-#include "exceptions.h"
+#include "gdb_bfd.h"
+#include "probe.h"
static struct link_map_offsets *svr4_fetch_link_map_offsets (void);
static int svr4_have_link_map_offsets (void);
+static void svr4_relocate_main_executable (void);
+static void svr4_free_library_list (void *p_list);
+static void probes_table_remove_objfile_probes (struct objfile *objfile);
+static void svr4_iterate_over_objfiles_in_search_order (
+ struct gdbarch *gdbarch, iterate_over_objfiles_in_search_order_cb_ftype *cb,
+ void *cb_data, struct objfile *objfile);
-/* Link map info to include in an allocated so_list entry */
-
-struct lm_info
- {
- /* Pointer to copy of link map from inferior. The type is char *
- rather than void *, so that we may use byte offsets to find the
- various fields without the need for a cast. */
- gdb_byte *lm;
-
- /* Amount by which addresses in the binary should be relocated to
- match the inferior. This could most often be taken directly
- from lm, but when prelinking is involved and the prelink base
- address changes, we may need a different offset, we want to
- warn about the difference and compute it only once. */
- CORE_ADDR l_addr;
-
- /* The target location of lm. */
- CORE_ADDR lm_addr;
- };
/* On SVR4 systems, a list of symbols in the dynamic linker where
GDB can try to place a breakpoint to monitor shared library
SVR4 systems will fall back to using a symbol as the "startup
mapping complete" breakpoint address. */
-static char *solib_break_names[] =
+static const char * const solib_break_names[] =
{
"r_debug_state",
"_r_debug_state",
"_dl_debug_state",
"rtld_db_dlactivity",
+ "__dl_rtld_db_dlactivity",
"_rtld_debug_state",
NULL
};
-static char *bkpt_names[] =
+static const char * const bkpt_names[] =
{
"_start",
"__start",
NULL
};
-static char *main_name_list[] =
+static const char * const main_name_list[] =
{
"main_$main",
NULL
};
+/* What to do when a probe stop occurs. */
+
+enum probe_action
+{
+ /* Something went seriously wrong. Stop using probes and
+ revert to using the older interface. */
+ PROBES_INTERFACE_FAILED,
+
+ /* No action is required. The shared object list is still
+ valid. */
+ DO_NOTHING,
+
+ /* The shared object list should be reloaded entirely. */
+ FULL_RELOAD,
+
+ /* Attempt to incrementally update the shared object list. If
+ the update fails or is not possible, fall back to reloading
+ the list in full. */
+ UPDATE_OR_RELOAD,
+};
+
+/* A probe's name and its associated action. */
+
+struct probe_info
+{
+ /* The name of the probe. */
+ const char *name;
+
+ /* What to do when a probe stop occurs. */
+ enum probe_action action;
+};
+
+/* A list of named probes and their associated actions. If all
+ probes are present in the dynamic linker then the probes-based
+ interface will be used. */
+
+static const struct probe_info probe_info[] =
+{
+ { "init_start", DO_NOTHING },
+ { "init_complete", FULL_RELOAD },
+ { "map_start", DO_NOTHING },
+ { "map_failed", DO_NOTHING },
+ { "reloc_complete", UPDATE_OR_RELOAD },
+ { "unmap_start", DO_NOTHING },
+ { "unmap_complete", FULL_RELOAD },
+};
+
+#define NUM_PROBES ARRAY_SIZE (probe_info)
+
/* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
the same shared library. */
return 1;
/* On Solaris, when starting inferior we think that dynamic linker is
- /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
- contains /lib/ld.so.1. Sometimes one file is a link to another, but
+ /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
+ contains /lib/ld.so.1. Sometimes one file is a link to another, but
sometimes they have identical content, but are not linked to each
other. We don't restrict this check for Solaris, but the chances
of running into this situation elsewhere are very low. */
&& strcmp (inferior_so_name, "/lib/ld.so.1") == 0)
return 1;
- /* Similarly, we observed the same issue with sparc64, but with
+ /* Similarly, we observed the same issue with amd64 and sparcv9, but with
different locations. */
+ if (strcmp (gdb_so_name, "/usr/lib/amd64/ld.so.1") == 0
+ && strcmp (inferior_so_name, "/lib/amd64/ld.so.1") == 0)
+ return 1;
+
if (strcmp (gdb_so_name, "/usr/lib/sparcv9/ld.so.1") == 0
&& strcmp (inferior_so_name, "/lib/sparcv9/ld.so.1") == 0)
return 1;
return (svr4_same_1 (gdb->so_original_name, inferior->so_original_name));
}
-/* link map access functions */
-
-static CORE_ADDR
-LM_ADDR_FROM_LINK_MAP (struct so_list *so)
+static std::unique_ptr<lm_info_svr4>
+lm_info_read (CORE_ADDR lm_addr)
{
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
+ std::unique_ptr<lm_info_svr4> lm_info;
- return extract_typed_address (so->lm_info->lm + lmo->l_addr_offset,
- builtin_type_void_data_ptr);
+ gdb::byte_vector lm (lmo->link_map_size);
+
+ if (target_read_memory (lm_addr, lm.data (), lmo->link_map_size) != 0)
+ warning (_("Error reading shared library list entry at %s"),
+ paddress (target_gdbarch (), lm_addr));
+ else
+ {
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
+
+ lm_info.reset (new lm_info_svr4);
+ lm_info->lm_addr = lm_addr;
+
+ lm_info->l_addr_inferior = extract_typed_address (&lm[lmo->l_addr_offset],
+ ptr_type);
+ lm_info->l_ld = extract_typed_address (&lm[lmo->l_ld_offset], ptr_type);
+ lm_info->l_next = extract_typed_address (&lm[lmo->l_next_offset],
+ ptr_type);
+ lm_info->l_prev = extract_typed_address (&lm[lmo->l_prev_offset],
+ ptr_type);
+ lm_info->l_name = extract_typed_address (&lm[lmo->l_name_offset],
+ ptr_type);
+ }
+
+ return lm_info;
}
static int
-HAS_LM_DYNAMIC_FROM_LINK_MAP ()
+has_lm_dynamic_from_link_map (void)
{
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
}
static CORE_ADDR
-LM_DYNAMIC_FROM_LINK_MAP (struct so_list *so)
+lm_addr_check (const struct so_list *so, bfd *abfd)
{
- struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
-
- return extract_typed_address (so->lm_info->lm + lmo->l_ld_offset,
- builtin_type_void_data_ptr);
-}
+ lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info;
-static CORE_ADDR
-LM_ADDR_CHECK (struct so_list *so, bfd *abfd)
-{
- if (so->lm_info->l_addr == (CORE_ADDR)-1)
+ if (!li->l_addr_p)
{
struct bfd_section *dyninfo_sect;
- CORE_ADDR l_addr, l_dynaddr, dynaddr, align = 0x1000;
+ CORE_ADDR l_addr, l_dynaddr, dynaddr;
- l_addr = LM_ADDR_FROM_LINK_MAP (so);
+ l_addr = li->l_addr_inferior;
- if (! abfd || ! HAS_LM_DYNAMIC_FROM_LINK_MAP ())
+ if (! abfd || ! has_lm_dynamic_from_link_map ())
goto set_addr;
- l_dynaddr = LM_DYNAMIC_FROM_LINK_MAP (so);
+ l_dynaddr = li->l_ld;
dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic");
if (dyninfo_sect == NULL)
goto set_addr;
- dynaddr = bfd_section_vma (abfd, dyninfo_sect);
+ dynaddr = bfd_section_vma (dyninfo_sect);
if (dynaddr + l_addr != l_dynaddr)
{
+ CORE_ADDR align = 0x1000;
+ CORE_ADDR minpagesize = align;
+
if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
{
Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header;
for (i = 0; i < ehdr->e_phnum; i++)
if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align)
align = phdr[i].p_align;
+
+ minpagesize = get_elf_backend_data (abfd)->minpagesize;
}
/* Turn it into a mask. */
location, or anything, really. To avoid regressions,
don't adjust the base offset in the latter case, although
odds are that, if things really changed, debugging won't
- quite work. */
- if ((l_addr & align) == ((l_dynaddr - dynaddr) & align))
+ quite work.
+
+ One could expect more the condition
+ ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
+ but the one below is relaxed for PPC. The PPC kernel supports
+ either 4k or 64k page sizes. To be prepared for 64k pages,
+ PPC ELF files are built using an alignment requirement of 64k.
+ However, when running on a kernel supporting 4k pages, the memory
+ mapping of the library may not actually happen on a 64k boundary!
+
+ (In the usual case where (l_addr & align) == 0, this check is
+ equivalent to the possibly expected check above.)
+
+ Even on PPC it must be zero-aligned at least for MINPAGESIZE. */
+
+ l_addr = l_dynaddr - dynaddr;
+
+ if ((l_addr & (minpagesize - 1)) == 0
+ && (l_addr & align) == ((l_dynaddr - dynaddr) & align))
+ {
+ if (info_verbose)
+ printf_unfiltered (_("Using PIC (Position Independent Code) "
+ "prelink displacement %s for \"%s\".\n"),
+ paddress (target_gdbarch (), l_addr),
+ so->so_name);
+ }
+ else
{
- l_addr = l_dynaddr - dynaddr;
+ /* There is no way to verify the library file matches. prelink
+ can during prelinking of an unprelinked file (or unprelinking
+ of a prelinked file) shift the DYNAMIC segment by arbitrary
+ offset without any page size alignment. There is no way to
+ find out the ELF header and/or Program Headers for a limited
+ verification if it they match. One could do a verification
+ of the DYNAMIC segment. Still the found address is the best
+ one GDB could find. */
warning (_(".dynamic section for \"%s\" "
- "is not at the expected address"), so->so_name);
- warning (_("difference appears to be caused by prelink, "
- "adjusting expectations"));
+ "is not at the expected address "
+ "(wrong library or version mismatch?)"), so->so_name);
}
- else
- warning (_(".dynamic section for \"%s\" "
- "is not at the expected address "
- "(wrong library or version mismatch?)"), so->so_name);
}
set_addr:
- so->lm_info->l_addr = l_addr;
+ li->l_addr = l_addr;
+ li->l_addr_p = 1;
}
- return so->lm_info->l_addr;
+ return li->l_addr;
}
-static CORE_ADDR
-LM_NEXT (struct so_list *so)
+/* Per pspace SVR4 specific data. */
+
+struct svr4_info
{
- struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
+ svr4_info () = default;
+ ~svr4_info ();
- return extract_typed_address (so->lm_info->lm + lmo->l_next_offset,
- builtin_type_void_data_ptr);
-}
+ /* Base of dynamic linker structures. */
+ CORE_ADDR debug_base = 0;
-static CORE_ADDR
-LM_NAME (struct so_list *so)
-{
- struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
+ /* Validity flag for debug_loader_offset. */
+ int debug_loader_offset_p = 0;
- return extract_typed_address (so->lm_info->lm + lmo->l_name_offset,
- builtin_type_void_data_ptr);
-}
+ /* Load address for the dynamic linker, inferred. */
+ CORE_ADDR debug_loader_offset = 0;
-static int
-IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so)
-{
- struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
+ /* Name of the dynamic linker, valid if debug_loader_offset_p. */
+ char *debug_loader_name = nullptr;
- /* Assume that everything is a library if the dynamic loader was loaded
- late by a static executable. */
- if (bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL)
- return 0;
+ /* Load map address for the main executable. */
+ CORE_ADDR main_lm_addr = 0;
- return extract_typed_address (so->lm_info->lm + lmo->l_prev_offset,
- builtin_type_void_data_ptr) == 0;
-}
+ CORE_ADDR interp_text_sect_low = 0;
+ CORE_ADDR interp_text_sect_high = 0;
+ CORE_ADDR interp_plt_sect_low = 0;
+ CORE_ADDR interp_plt_sect_high = 0;
-static CORE_ADDR debug_base; /* Base of dynamic linker structures */
+ /* Nonzero if the list of objects was last obtained from the target
+ via qXfer:libraries-svr4:read. */
+ int using_xfer = 0;
-/* Validity flag for debug_loader_offset. */
-static int debug_loader_offset_p;
+ /* Table of struct probe_and_action instances, used by the
+ probes-based interface to map breakpoint addresses to probes
+ and their associated actions. Lookup is performed using
+ probe_and_action->prob->address. */
+ htab_up probes_table;
-/* Load address for the dynamic linker, inferred. */
-static CORE_ADDR debug_loader_offset;
+ /* List of objects loaded into the inferior, used by the probes-
+ based interface. */
+ struct so_list *solib_list = nullptr;
+};
-/* Name of the dynamic linker, valid if debug_loader_offset_p. */
-static char *debug_loader_name;
+/* Per-program-space data key. */
+static const struct program_space_key<svr4_info> solib_svr4_pspace_data;
-/* Load map address for the main executable. */
-static CORE_ADDR main_lm_addr;
+/* Free the probes table. */
-/* Local function prototypes */
+static void
+free_probes_table (struct svr4_info *info)
+{
+ info->probes_table.reset (nullptr);
+}
+
+/* Free the solib list. */
-static int match_main (char *);
+static void
+free_solib_list (struct svr4_info *info)
+{
+ svr4_free_library_list (&info->solib_list);
+ info->solib_list = NULL;
+}
-static CORE_ADDR bfd_lookup_symbol (bfd *, char *);
+svr4_info::~svr4_info ()
+{
+ free_solib_list (this);
+}
-/*
+/* Get the svr4 data for program space PSPACE. If none is found yet, add it now.
+ This function always returns a valid object. */
- LOCAL FUNCTION
+static struct svr4_info *
+get_svr4_info (program_space *pspace)
+{
+ struct svr4_info *info = solib_svr4_pspace_data.get (pspace);
- bfd_lookup_symbol -- lookup the value for a specific symbol
+ if (info == NULL)
+ info = solib_svr4_pspace_data.emplace (pspace);
- SYNOPSIS
+ return info;
+}
- CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
+/* Local function prototypes */
- DESCRIPTION
+static int match_main (const char *);
- An expensive way to lookup the value of a single symbol for
- bfd's that are only temporary anyway. This is used by the
- shared library support to find the address of the debugger
- notification routine in the shared library.
+/* Read program header TYPE from inferior memory. The header is found
+ by scanning the OS auxiliary vector.
- The returned symbol may be in a code or data section; functions
- will normally be in a code section, but may be in a data section
- if this architecture uses function descriptors.
+ If TYPE == -1, return the program headers instead of the contents of
+ one program header.
- Note that 0 is specifically allowed as an error return (no
- such symbol).
- */
+ Return vector of bytes holding the program header contents, or an empty
+ optional on failure. If successful and P_ARCH_SIZE is non-NULL, the target
+ architecture size (32-bit or 64-bit) is returned to *P_ARCH_SIZE. Likewise,
+ the base address of the section is returned in *BASE_ADDR. */
-static CORE_ADDR
-bfd_lookup_symbol (bfd *abfd, char *symname)
+static gdb::optional<gdb::byte_vector>
+read_program_header (int type, int *p_arch_size, CORE_ADDR *base_addr)
{
- long storage_needed;
- asymbol *sym;
- asymbol **symbol_table;
- unsigned int number_of_symbols;
- unsigned int i;
- struct cleanup *back_to;
- CORE_ADDR symaddr = 0;
-
- storage_needed = bfd_get_symtab_upper_bound (abfd);
+ enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
+ CORE_ADDR at_phdr, at_phent, at_phnum, pt_phdr = 0;
+ int arch_size, sect_size;
+ CORE_ADDR sect_addr;
+ int pt_phdr_p = 0;
+
+ /* Get required auxv elements from target. */
+ if (target_auxv_search (current_top_target (), AT_PHDR, &at_phdr) <= 0)
+ return {};
+ if (target_auxv_search (current_top_target (), AT_PHENT, &at_phent) <= 0)
+ return {};
+ if (target_auxv_search (current_top_target (), AT_PHNUM, &at_phnum) <= 0)
+ return {};
+ if (!at_phdr || !at_phnum)
+ return {};
+
+ /* Determine ELF architecture type. */
+ if (at_phent == sizeof (Elf32_External_Phdr))
+ arch_size = 32;
+ else if (at_phent == sizeof (Elf64_External_Phdr))
+ arch_size = 64;
+ else
+ return {};
- if (storage_needed > 0)
+ /* Find the requested segment. */
+ if (type == -1)
+ {
+ sect_addr = at_phdr;
+ sect_size = at_phent * at_phnum;
+ }
+ else if (arch_size == 32)
{
- symbol_table = (asymbol **) xmalloc (storage_needed);
- back_to = make_cleanup (xfree, symbol_table);
- number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
+ Elf32_External_Phdr phdr;
+ int i;
- for (i = 0; i < number_of_symbols; i++)
+ /* Search for requested PHDR. */
+ for (i = 0; i < at_phnum; i++)
{
- sym = *symbol_table++;
- if (strcmp (sym->name, symname) == 0
- && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
+ int p_type;
+
+ if (target_read_memory (at_phdr + i * sizeof (phdr),
+ (gdb_byte *)&phdr, sizeof (phdr)))
+ return {};
+
+ p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type,
+ 4, byte_order);
+
+ if (p_type == PT_PHDR)
{
- /* BFD symbols are section relative. */
- symaddr = sym->value + sym->section->vma;
- break;
+ pt_phdr_p = 1;
+ pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr,
+ 4, byte_order);
}
- }
- do_cleanups (back_to);
- }
-
- if (symaddr)
- return symaddr;
- /* On FreeBSD, the dynamic linker is stripped by default. So we'll
- have to check the dynamic string table too. */
+ if (p_type == type)
+ break;
+ }
- storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
+ if (i == at_phnum)
+ return {};
- if (storage_needed > 0)
+ /* Retrieve address and size. */
+ sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
+ 4, byte_order);
+ sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz,
+ 4, byte_order);
+ }
+ else
{
- symbol_table = (asymbol **) xmalloc (storage_needed);
- back_to = make_cleanup (xfree, symbol_table);
- number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
+ Elf64_External_Phdr phdr;
+ int i;
- for (i = 0; i < number_of_symbols; i++)
+ /* Search for requested PHDR. */
+ for (i = 0; i < at_phnum; i++)
{
- sym = *symbol_table++;
+ int p_type;
+
+ if (target_read_memory (at_phdr + i * sizeof (phdr),
+ (gdb_byte *)&phdr, sizeof (phdr)))
+ return {};
+
+ p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type,
+ 4, byte_order);
- if (strcmp (sym->name, symname) == 0
- && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
+ if (p_type == PT_PHDR)
{
- /* BFD symbols are section relative. */
- symaddr = sym->value + sym->section->vma;
- break;
+ pt_phdr_p = 1;
+ pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr,
+ 8, byte_order);
}
+
+ if (p_type == type)
+ break;
}
- do_cleanups (back_to);
+
+ if (i == at_phnum)
+ return {};
+
+ /* Retrieve address and size. */
+ sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
+ 8, byte_order);
+ sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz,
+ 8, byte_order);
+ }
+
+ /* PT_PHDR is optional, but we really need it
+ for PIE to make this work in general. */
+
+ if (pt_phdr_p)
+ {
+ /* at_phdr is real address in memory. pt_phdr is what pheader says it is.
+ Relocation offset is the difference between the two. */
+ sect_addr = sect_addr + (at_phdr - pt_phdr);
}
- return symaddr;
+ /* Read in requested program header. */
+ gdb::byte_vector buf (sect_size);
+ if (target_read_memory (sect_addr, buf.data (), sect_size))
+ return {};
+
+ if (p_arch_size)
+ *p_arch_size = arch_size;
+ if (base_addr)
+ *base_addr = sect_addr;
+
+ return buf;
+}
+
+
+/* Return program interpreter string. */
+static gdb::optional<gdb::byte_vector>
+find_program_interpreter (void)
+{
+ /* If we have an exec_bfd, use its section table. */
+ if (exec_bfd
+ && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
+ {
+ struct bfd_section *interp_sect;
+
+ interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
+ if (interp_sect != NULL)
+ {
+ int sect_size = bfd_section_size (interp_sect);
+
+ gdb::byte_vector buf (sect_size);
+ bfd_get_section_contents (exec_bfd, interp_sect, buf.data (), 0,
+ sect_size);
+ return buf;
+ }
+ }
+
+ /* If we didn't find it, use the target auxiliary vector. */
+ return read_program_header (PT_INTERP, NULL, NULL);
}
-/* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is
- returned and the corresponding PTR is set. */
+
+/* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is
+ found, 1 is returned and the corresponding PTR is set. */
static int
-scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr)
+scan_dyntag (const int desired_dyntag, bfd *abfd, CORE_ADDR *ptr,
+ CORE_ADDR *ptr_addr)
{
int arch_size, step, sect_size;
- long dyn_tag;
+ long current_dyntag;
CORE_ADDR dyn_ptr, dyn_addr;
gdb_byte *bufend, *bufstart, *buf;
Elf32_External_Dyn *x_dynp_32;
Elf64_External_Dyn *x_dynp_64;
struct bfd_section *sect;
+ struct target_section *target_section;
if (abfd == NULL)
return 0;
+
+ if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
+ return 0;
+
arch_size = bfd_get_arch_size (abfd);
if (arch_size == -1)
- return 0;
+ return 0;
/* Find the start address of the .dynamic section. */
sect = bfd_get_section_by_name (abfd, ".dynamic");
if (sect == NULL)
return 0;
- dyn_addr = bfd_section_vma (abfd, sect);
+
+ for (target_section = current_target_sections->sections;
+ target_section < current_target_sections->sections_end;
+ target_section++)
+ if (sect == target_section->the_bfd_section)
+ break;
+ if (target_section < current_target_sections->sections_end)
+ dyn_addr = target_section->addr;
+ else
+ {
+ /* ABFD may come from OBJFILE acting only as a symbol file without being
+ loaded into the target (see add_symbol_file_command). This case is
+ such fallback to the file VMA address without the possibility of
+ having the section relocated to its actual in-memory address. */
+
+ dyn_addr = bfd_section_vma (sect);
+ }
/* Read in .dynamic from the BFD. We will get the actual value
from memory later. */
- sect_size = bfd_section_size (abfd, sect);
- buf = bufstart = alloca (sect_size);
+ sect_size = bfd_section_size (sect);
+ buf = bufstart = (gdb_byte *) alloca (sect_size);
if (!bfd_get_section_contents (abfd, sect,
buf, 0, sect_size))
return 0;
if (arch_size == 32)
{
x_dynp_32 = (Elf32_External_Dyn *) buf;
- dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag);
+ current_dyntag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag);
dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr);
}
else
{
x_dynp_64 = (Elf64_External_Dyn *) buf;
- dyn_tag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag);
+ current_dyntag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag);
dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr);
}
- if (dyn_tag == DT_NULL)
+ if (current_dyntag == DT_NULL)
return 0;
- if (dyn_tag == dyntag)
+ if (current_dyntag == desired_dyntag)
{
/* If requested, try to read the runtime value of this .dynamic
entry. */
if (ptr)
{
+ struct type *ptr_type;
gdb_byte ptr_buf[8];
- CORE_ADDR ptr_addr;
+ CORE_ADDR ptr_addr_1;
- ptr_addr = dyn_addr + (buf - bufstart) + arch_size / 8;
- if (target_read_memory (ptr_addr, ptr_buf, arch_size / 8) == 0)
- dyn_ptr = extract_typed_address (ptr_buf,
- builtin_type_void_data_ptr);
+ ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
+ ptr_addr_1 = dyn_addr + (buf - bufstart) + arch_size / 8;
+ if (target_read_memory (ptr_addr_1, ptr_buf, arch_size / 8) == 0)
+ dyn_ptr = extract_typed_address (ptr_buf, ptr_type);
*ptr = dyn_ptr;
+ if (ptr_addr)
+ *ptr_addr = dyn_addr + (buf - bufstart);
}
return 1;
}
return 0;
}
+/* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable,
+ found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1
+ is returned and the corresponding PTR is set. */
+
+static int
+scan_dyntag_auxv (const int desired_dyntag, CORE_ADDR *ptr,
+ CORE_ADDR *ptr_addr)
+{
+ enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
+ int arch_size, step;
+ long current_dyntag;
+ CORE_ADDR dyn_ptr;
+ CORE_ADDR base_addr;
+
+ /* Read in .dynamic section. */
+ gdb::optional<gdb::byte_vector> ph_data
+ = read_program_header (PT_DYNAMIC, &arch_size, &base_addr);
+ if (!ph_data)
+ return 0;
+
+ /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
+ step = (arch_size == 32) ? sizeof (Elf32_External_Dyn)
+ : sizeof (Elf64_External_Dyn);
+ for (gdb_byte *buf = ph_data->data (), *bufend = buf + ph_data->size ();
+ buf < bufend; buf += step)
+ {
+ if (arch_size == 32)
+ {
+ Elf32_External_Dyn *dynp = (Elf32_External_Dyn *) buf;
+
+ current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag,
+ 4, byte_order);
+ dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr,
+ 4, byte_order);
+ }
+ else
+ {
+ Elf64_External_Dyn *dynp = (Elf64_External_Dyn *) buf;
-/*
+ current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag,
+ 8, byte_order);
+ dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr,
+ 8, byte_order);
+ }
+ if (current_dyntag == DT_NULL)
+ break;
- LOCAL FUNCTION
+ if (current_dyntag == desired_dyntag)
+ {
+ if (ptr)
+ *ptr = dyn_ptr;
- elf_locate_base -- locate the base address of dynamic linker structs
- for SVR4 elf targets.
+ if (ptr_addr)
+ *ptr_addr = base_addr + buf - ph_data->data ();
- SYNOPSIS
+ return 1;
+ }
+ }
- CORE_ADDR elf_locate_base (void)
+ return 0;
+}
- DESCRIPTION
+/* Locate the base address of dynamic linker structs for SVR4 elf
+ targets.
For SVR4 elf targets the address of the dynamic linker's runtime
structure is contained within the dynamic info section in the
real address before starting the inferior, we have to read in the
dynamic info section from the inferior address space.
If there are any errors while trying to find the address, we
- silently return 0, otherwise the found address is returned.
-
- */
+ silently return 0, otherwise the found address is returned. */
static CORE_ADDR
elf_locate_base (void)
{
- struct minimal_symbol *msymbol;
- CORE_ADDR dyn_ptr;
+ struct bound_minimal_symbol msymbol;
+ CORE_ADDR dyn_ptr, dyn_ptr_addr;
/* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
instead of DT_DEBUG, although they sometimes contain an unused
DT_DEBUG. */
- if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr))
+ if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr, NULL)
+ || scan_dyntag_auxv (DT_MIPS_RLD_MAP, &dyn_ptr, NULL))
{
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
gdb_byte *pbuf;
- int pbuf_size = TYPE_LENGTH (builtin_type_void_data_ptr);
- pbuf = alloca (pbuf_size);
+ int pbuf_size = TYPE_LENGTH (ptr_type);
+
+ pbuf = (gdb_byte *) alloca (pbuf_size);
/* DT_MIPS_RLD_MAP contains a pointer to the address
of the dynamic link structure. */
if (target_read_memory (dyn_ptr, pbuf, pbuf_size))
return 0;
- return extract_typed_address (pbuf, builtin_type_void_data_ptr);
+ return extract_typed_address (pbuf, ptr_type);
+ }
+
+ /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form
+ because of needing to support PIE. DT_MIPS_RLD_MAP will also exist
+ in non-PIE. */
+ if (scan_dyntag (DT_MIPS_RLD_MAP_REL, exec_bfd, &dyn_ptr, &dyn_ptr_addr)
+ || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL, &dyn_ptr, &dyn_ptr_addr))
+ {
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
+ gdb_byte *pbuf;
+ int pbuf_size = TYPE_LENGTH (ptr_type);
+
+ pbuf = (gdb_byte *) alloca (pbuf_size);
+ /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the
+ DT slot to the address of the dynamic link structure. */
+ if (target_read_memory (dyn_ptr + dyn_ptr_addr, pbuf, pbuf_size))
+ return 0;
+ return extract_typed_address (pbuf, ptr_type);
}
/* Find DT_DEBUG. */
- if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr))
+ if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr, NULL)
+ || scan_dyntag_auxv (DT_DEBUG, &dyn_ptr, NULL))
return dyn_ptr;
/* This may be a static executable. Look for the symbol
conventionally named _r_debug, as a last resort. */
msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile);
- if (msymbol != NULL)
- return SYMBOL_VALUE_ADDRESS (msymbol);
+ if (msymbol.minsym != NULL)
+ return BMSYMBOL_VALUE_ADDRESS (msymbol);
/* DT_DEBUG entry not found. */
return 0;
}
-/*
-
- LOCAL FUNCTION
-
- locate_base -- locate the base address of dynamic linker structs
-
- SYNOPSIS
-
- CORE_ADDR locate_base (void)
-
- DESCRIPTION
+/* Locate the base address of dynamic linker structs.
For both the SunOS and SVR4 shared library implementations, if the
inferior executable has been linked dynamically, there is a single
to a lot more work to discover the address of the debug base symbol.
Because of this complexity, we cache the value we find and return that
value on subsequent invocations. Note there is no copy in the
- executable symbol tables.
-
- */
+ executable symbol tables. */
static CORE_ADDR
-locate_base (void)
+locate_base (struct svr4_info *info)
{
/* Check to see if we have a currently valid address, and if so, avoid
doing all this work again and just return the cached address. If
section for ELF executables. There's no point in doing any of this
though if we don't have some link map offsets to work with. */
- if (debug_base == 0 && svr4_have_link_map_offsets ())
- {
- if (exec_bfd != NULL
- && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
- debug_base = elf_locate_base ();
- }
- return (debug_base);
+ if (info->debug_base == 0 && svr4_have_link_map_offsets ())
+ info->debug_base = elf_locate_base ();
+ return info->debug_base;
}
/* Find the first element in the inferior's dynamic link map, and
- return its address in the inferior.
+ return its address in the inferior. Return zero if the address
+ could not be determined.
FIXME: Perhaps we should validate the info somehow, perhaps by
checking r_version for a known version number, or r_state for
RT_CONSISTENT. */
static CORE_ADDR
-solib_svr4_r_map (void)
+solib_svr4_r_map (struct svr4_info *info)
{
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
+ CORE_ADDR addr = 0;
+
+ try
+ {
+ addr = read_memory_typed_address (info->debug_base + lmo->r_map_offset,
+ ptr_type);
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ exception_print (gdb_stderr, ex);
+ }
- return read_memory_typed_address (debug_base + lmo->r_map_offset,
- builtin_type_void_data_ptr);
+ return addr;
}
/* Find r_brk from the inferior's debug base. */
static CORE_ADDR
-solib_svr4_r_brk (void)
+solib_svr4_r_brk (struct svr4_info *info)
{
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
- return read_memory_typed_address (debug_base + lmo->r_brk_offset,
- builtin_type_void_data_ptr);
+ return read_memory_typed_address (info->debug_base + lmo->r_brk_offset,
+ ptr_type);
}
/* Find the link map for the dynamic linker (if it is not in the
normal list of loaded shared objects). */
static CORE_ADDR
-solib_svr4_r_ldsomap (void)
+solib_svr4_r_ldsomap (struct svr4_info *info)
{
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
- ULONGEST version;
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
+ enum bfd_endian byte_order = type_byte_order (ptr_type);
+ ULONGEST version = 0;
+
+ try
+ {
+ /* Check version, and return zero if `struct r_debug' doesn't have
+ the r_ldsomap member. */
+ version
+ = read_memory_unsigned_integer (info->debug_base + lmo->r_version_offset,
+ lmo->r_version_size, byte_order);
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ exception_print (gdb_stderr, ex);
+ }
- /* Check version, and return zero if `struct r_debug' doesn't have
- the r_ldsomap member. */
- version = read_memory_unsigned_integer (debug_base + lmo->r_version_offset,
- lmo->r_version_size);
if (version < 2 || lmo->r_ldsomap_offset == -1)
return 0;
- return read_memory_typed_address (debug_base + lmo->r_ldsomap_offset,
- builtin_type_void_data_ptr);
+ return read_memory_typed_address (info->debug_base + lmo->r_ldsomap_offset,
+ ptr_type);
}
-/*
+/* On Solaris systems with some versions of the dynamic linker,
+ ld.so's l_name pointer points to the SONAME in the string table
+ rather than into writable memory. So that GDB can find shared
+ libraries when loading a core file generated by gcore, ensure that
+ memory areas containing the l_name string are saved in the core
+ file. */
- LOCAL FUNCTION
+static int
+svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size)
+{
+ struct svr4_info *info;
+ CORE_ADDR ldsomap;
+ CORE_ADDR name_lm;
- open_symbol_file_object
+ info = get_svr4_info (current_program_space);
- SYNOPSIS
+ info->debug_base = 0;
+ locate_base (info);
+ if (!info->debug_base)
+ return 0;
- void open_symbol_file_object (void *from_tty)
+ ldsomap = solib_svr4_r_ldsomap (info);
+ if (!ldsomap)
+ return 0;
- DESCRIPTION
+ std::unique_ptr<lm_info_svr4> li = lm_info_read (ldsomap);
+ name_lm = li != NULL ? li->l_name : 0;
- If no open symbol file, attempt to locate and open the main symbol
- file. On SVR4 systems, this is the first link map entry. If its
- name is here, we can open it. Useful when attaching to a process
- without first loading its symbol file.
+ return (name_lm >= vaddr && name_lm < vaddr + size);
+}
- If FROM_TTYP dereferences to a non-zero integer, allow messages to
- be printed. This parameter is a pointer rather than an int because
- open_symbol_file_object() is called via catch_errors() and
- catch_errors() requires a pointer argument. */
+/* See solist.h. */
static int
-open_symbol_file_object (void *from_ttyp)
+open_symbol_file_object (int from_tty)
{
CORE_ADDR lm, l_name;
- char *filename;
+ gdb::unique_xmalloc_ptr<char> filename;
int errcode;
- int from_tty = *(int *)from_ttyp;
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
- int l_name_size = TYPE_LENGTH (builtin_type_void_data_ptr);
- gdb_byte *l_name_buf = xmalloc (l_name_size);
- struct cleanup *cleanups = make_cleanup (xfree, l_name_buf);
+ struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
+ int l_name_size = TYPE_LENGTH (ptr_type);
+ gdb::byte_vector l_name_buf (l_name_size);
+ struct svr4_info *info = get_svr4_info (current_program_space);
+ symfile_add_flags add_flags = 0;
+
+ if (from_tty)
+ add_flags |= SYMFILE_VERBOSE;
if (symfile_objfile)
- if (!query ("Attempt to reload symbols from process? "))
+ if (!query (_("Attempt to reload symbols from process? ")))
return 0;
/* Always locate the debug struct, in case it has moved. */
- debug_base = 0;
- if (locate_base () == 0)
- return 0; /* failed somehow... */
+ info->debug_base = 0;
+ if (locate_base (info) == 0)
+ return 0; /* failed somehow... */
/* First link map member should be the executable. */
- lm = solib_svr4_r_map ();
+ lm = solib_svr4_r_map (info);
if (lm == 0)
- return 0; /* failed somehow... */
+ return 0; /* failed somehow... */
/* Read address of name from target memory to GDB. */
- read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size);
+ read_memory (lm + lmo->l_name_offset, l_name_buf.data (), l_name_size);
/* Convert the address to host format. */
- l_name = extract_typed_address (l_name_buf, builtin_type_void_data_ptr);
-
- /* Free l_name_buf. */
- do_cleanups (cleanups);
+ l_name = extract_typed_address (l_name_buf.data (), ptr_type);
if (l_name == 0)
return 0; /* No filename. */
/* Now fetch the filename from target memory. */
target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode);
- make_cleanup (xfree, filename);
- if (errcode)
- {
- warning (_("failed to read exec filename from attached file: %s"),
- safe_strerror (errcode));
- return 0;
+ if (errcode)
+ {
+ warning (_("failed to read exec filename from attached file: %s"),
+ safe_strerror (errcode));
+ return 0;
+ }
+
+ /* Have a pathname: read the symbol file. */
+ symbol_file_add_main (filename.get (), add_flags);
+
+ return 1;
+}
+
+/* Data exchange structure for the XML parser as returned by
+ svr4_current_sos_via_xfer_libraries. */
+
+struct svr4_library_list
+{
+ struct so_list *head, **tailp;
+
+ /* Inferior address of struct link_map used for the main executable. It is
+ NULL if not known. */
+ CORE_ADDR main_lm;
+};
+
+/* This module's 'free_objfile' observer. */
+
+static void
+svr4_free_objfile_observer (struct objfile *objfile)
+{
+ probes_table_remove_objfile_probes (objfile);
+}
+
+/* Implementation for target_so_ops.free_so. */
+
+static void
+svr4_free_so (struct so_list *so)
+{
+ lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info;
+
+ delete li;
+}
+
+/* Implement target_so_ops.clear_so. */
+
+static void
+svr4_clear_so (struct so_list *so)
+{
+ lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info;
+
+ if (li != NULL)
+ li->l_addr_p = 0;
+}
+
+/* Free so_list built so far (called via cleanup). */
+
+static void
+svr4_free_library_list (void *p_list)
+{
+ struct so_list *list = *(struct so_list **) p_list;
+
+ while (list != NULL)
+ {
+ struct so_list *next = list->next;
+
+ free_so (list);
+ list = next;
+ }
+}
+
+/* Copy library list. */
+
+static struct so_list *
+svr4_copy_library_list (struct so_list *src)
+{
+ struct so_list *dst = NULL;
+ struct so_list **link = &dst;
+
+ while (src != NULL)
+ {
+ struct so_list *newobj;
+
+ newobj = XNEW (struct so_list);
+ memcpy (newobj, src, sizeof (struct so_list));
+
+ lm_info_svr4 *src_li = (lm_info_svr4 *) src->lm_info;
+ newobj->lm_info = new lm_info_svr4 (*src_li);
+
+ newobj->next = NULL;
+ *link = newobj;
+ link = &newobj->next;
+
+ src = src->next;
+ }
+
+ return dst;
+}
+
+#ifdef HAVE_LIBEXPAT
+
+#include "xml-support.h"
+
+/* Handle the start of a <library> element. Note: new elements are added
+ at the tail of the list, keeping the list in order. */
+
+static void
+library_list_start_library (struct gdb_xml_parser *parser,
+ const struct gdb_xml_element *element,
+ void *user_data,
+ std::vector<gdb_xml_value> &attributes)
+{
+ struct svr4_library_list *list = (struct svr4_library_list *) user_data;
+ const char *name
+ = (const char *) xml_find_attribute (attributes, "name")->value.get ();
+ ULONGEST *lmp
+ = (ULONGEST *) xml_find_attribute (attributes, "lm")->value.get ();
+ ULONGEST *l_addrp
+ = (ULONGEST *) xml_find_attribute (attributes, "l_addr")->value.get ();
+ ULONGEST *l_ldp
+ = (ULONGEST *) xml_find_attribute (attributes, "l_ld")->value.get ();
+ struct so_list *new_elem;
+
+ new_elem = XCNEW (struct so_list);
+ lm_info_svr4 *li = new lm_info_svr4;
+ new_elem->lm_info = li;
+ li->lm_addr = *lmp;
+ li->l_addr_inferior = *l_addrp;
+ li->l_ld = *l_ldp;
+
+ strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1);
+ new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0;
+ strcpy (new_elem->so_original_name, new_elem->so_name);
+
+ *list->tailp = new_elem;
+ list->tailp = &new_elem->next;
+}
+
+/* Handle the start of a <library-list-svr4> element. */
+
+static void
+svr4_library_list_start_list (struct gdb_xml_parser *parser,
+ const struct gdb_xml_element *element,
+ void *user_data,
+ std::vector<gdb_xml_value> &attributes)
+{
+ struct svr4_library_list *list = (struct svr4_library_list *) user_data;
+ const char *version
+ = (const char *) xml_find_attribute (attributes, "version")->value.get ();
+ struct gdb_xml_value *main_lm = xml_find_attribute (attributes, "main-lm");
+
+ if (strcmp (version, "1.0") != 0)
+ gdb_xml_error (parser,
+ _("SVR4 Library list has unsupported version \"%s\""),
+ version);
+
+ if (main_lm)
+ list->main_lm = *(ULONGEST *) main_lm->value.get ();
+}
+
+/* The allowed elements and attributes for an XML library list.
+ The root element is a <library-list>. */
+
+static const struct gdb_xml_attribute svr4_library_attributes[] =
+{
+ { "name", GDB_XML_AF_NONE, NULL, NULL },
+ { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
+ { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
+ { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
+ { NULL, GDB_XML_AF_NONE, NULL, NULL }
+};
+
+static const struct gdb_xml_element svr4_library_list_children[] =
+{
+ {
+ "library", svr4_library_attributes, NULL,
+ GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
+ library_list_start_library, NULL
+ },
+ { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
+};
+
+static const struct gdb_xml_attribute svr4_library_list_attributes[] =
+{
+ { "version", GDB_XML_AF_NONE, NULL, NULL },
+ { "main-lm", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+ { NULL, GDB_XML_AF_NONE, NULL, NULL }
+};
+
+static const struct gdb_xml_element svr4_library_list_elements[] =
+{
+ { "library-list-svr4", svr4_library_list_attributes, svr4_library_list_children,
+ GDB_XML_EF_NONE, svr4_library_list_start_list, NULL },
+ { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
+};
+
+/* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if
+
+ Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
+ case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
+ empty, caller is responsible for freeing all its entries. */
+
+static int
+svr4_parse_libraries (const char *document, struct svr4_library_list *list)
+{
+ auto cleanup = make_scope_exit ([&] ()
+ {
+ svr4_free_library_list (&list->head);
+ });
+
+ memset (list, 0, sizeof (*list));
+ list->tailp = &list->head;
+ if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd",
+ svr4_library_list_elements, document, list) == 0)
+ {
+ /* Parsed successfully, keep the result. */
+ cleanup.release ();
+ return 1;
+ }
+
+ return 0;
+}
+
+/* Attempt to get so_list from target via qXfer:libraries-svr4:read packet.
+
+ Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
+ case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
+ empty, caller is responsible for freeing all its entries.
+
+ Note that ANNEX must be NULL if the remote does not explicitly allow
+ qXfer:libraries-svr4:read packets with non-empty annexes. Support for
+ this can be checked using target_augmented_libraries_svr4_read (). */
+
+static int
+svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list,
+ const char *annex)
+{
+ gdb_assert (annex == NULL || target_augmented_libraries_svr4_read ());
+
+ /* Fetch the list of shared libraries. */
+ gdb::optional<gdb::char_vector> svr4_library_document
+ = target_read_stralloc (current_top_target (), TARGET_OBJECT_LIBRARIES_SVR4,
+ annex);
+ if (!svr4_library_document)
+ return 0;
+
+ return svr4_parse_libraries (svr4_library_document->data (), list);
+}
+
+#else
+
+static int
+svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list,
+ const char *annex)
+{
+ return 0;
+}
+
+#endif
+
+/* If no shared library information is available from the dynamic
+ linker, build a fallback list from other sources. */
+
+static struct so_list *
+svr4_default_sos (svr4_info *info)
+{
+ struct so_list *newobj;
+
+ if (!info->debug_loader_offset_p)
+ return NULL;
+
+ newobj = XCNEW (struct so_list);
+ lm_info_svr4 *li = new lm_info_svr4;
+ newobj->lm_info = li;
+
+ /* Nothing will ever check the other fields if we set l_addr_p. */
+ li->l_addr = info->debug_loader_offset;
+ li->l_addr_p = 1;
+
+ strncpy (newobj->so_name, info->debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1);
+ newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
+ strcpy (newobj->so_original_name, newobj->so_name);
+
+ return newobj;
+}
+
+/* Read the whole inferior libraries chain starting at address LM.
+ Expect the first entry in the chain's previous entry to be PREV_LM.
+ Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the
+ first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according
+ to it. Returns nonzero upon success. If zero is returned the
+ entries stored to LINK_PTR_PTR are still valid although they may
+ represent only part of the inferior library list. */
+
+static int
+svr4_read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm,
+ struct so_list ***link_ptr_ptr, int ignore_first)
+{
+ CORE_ADDR first_l_name = 0;
+ CORE_ADDR next_lm;
+
+ for (; lm != 0; prev_lm = lm, lm = next_lm)
+ {
+ int errcode;
+ gdb::unique_xmalloc_ptr<char> buffer;
+
+ so_list_up newobj (XCNEW (struct so_list));
+
+ lm_info_svr4 *li = lm_info_read (lm).release ();
+ newobj->lm_info = li;
+ if (li == NULL)
+ return 0;
+
+ next_lm = li->l_next;
+
+ if (li->l_prev != prev_lm)
+ {
+ warning (_("Corrupted shared library list: %s != %s"),
+ paddress (target_gdbarch (), prev_lm),
+ paddress (target_gdbarch (), li->l_prev));
+ return 0;
+ }
+
+ /* For SVR4 versions, the first entry in the link map is for the
+ inferior executable, so we must ignore it. For some versions of
+ SVR4, it has no name. For others (Solaris 2.3 for example), it
+ does have a name, so we can no longer use a missing name to
+ decide when to ignore it. */
+ if (ignore_first && li->l_prev == 0)
+ {
+ first_l_name = li->l_name;
+ info->main_lm_addr = li->lm_addr;
+ continue;
+ }
+
+ /* Extract this shared object's name. */
+ target_read_string (li->l_name, &buffer, SO_NAME_MAX_PATH_SIZE - 1,
+ &errcode);
+ if (errcode != 0)
+ {
+ /* If this entry's l_name address matches that of the
+ inferior executable, then this is not a normal shared
+ object, but (most likely) a vDSO. In this case, silently
+ skip it; otherwise emit a warning. */
+ if (first_l_name == 0 || li->l_name != first_l_name)
+ warning (_("Can't read pathname for load map: %s."),
+ safe_strerror (errcode));
+ continue;
+ }
+
+ strncpy (newobj->so_name, buffer.get (), SO_NAME_MAX_PATH_SIZE - 1);
+ newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
+ strcpy (newobj->so_original_name, newobj->so_name);
+
+ /* If this entry has no name, or its name matches the name
+ for the main executable, don't include it in the list. */
+ if (! newobj->so_name[0] || match_main (newobj->so_name))
+ continue;
+
+ newobj->next = 0;
+ /* Don't free it now. */
+ **link_ptr_ptr = newobj.release ();
+ *link_ptr_ptr = &(**link_ptr_ptr)->next;
+ }
+
+ return 1;
+}
+
+/* Read the full list of currently loaded shared objects directly
+ from the inferior, without referring to any libraries read and
+ stored by the probes interface. Handle special cases relating
+ to the first elements of the list. */
+
+static struct so_list *
+svr4_current_sos_direct (struct svr4_info *info)
+{
+ CORE_ADDR lm;
+ struct so_list *head = NULL;
+ struct so_list **link_ptr = &head;
+ int ignore_first;
+ struct svr4_library_list library_list;
+
+ /* Fall back to manual examination of the target if the packet is not
+ supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp
+ tests a case where gdbserver cannot find the shared libraries list while
+ GDB itself is able to find it via SYMFILE_OBJFILE.
+
+ Unfortunately statically linked inferiors will also fall back through this
+ suboptimal code path. */
+
+ info->using_xfer = svr4_current_sos_via_xfer_libraries (&library_list,
+ NULL);
+ if (info->using_xfer)
+ {
+ if (library_list.main_lm)
+ info->main_lm_addr = library_list.main_lm;
+
+ return library_list.head ? library_list.head : svr4_default_sos (info);
+ }
+
+ /* Always locate the debug struct, in case it has moved. */
+ info->debug_base = 0;
+ locate_base (info);
+
+ /* If we can't find the dynamic linker's base structure, this
+ must not be a dynamically linked executable. Hmm. */
+ if (! info->debug_base)
+ return svr4_default_sos (info);
+
+ /* Assume that everything is a library if the dynamic loader was loaded
+ late by a static executable. */
+ if (exec_bfd && bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL)
+ ignore_first = 0;
+ else
+ ignore_first = 1;
+
+ auto cleanup = make_scope_exit ([&] ()
+ {
+ svr4_free_library_list (&head);
+ });
+
+ /* Walk the inferior's link map list, and build our list of
+ `struct so_list' nodes. */
+ lm = solib_svr4_r_map (info);
+ if (lm)
+ svr4_read_so_list (info, lm, 0, &link_ptr, ignore_first);
+
+ /* On Solaris, the dynamic linker is not in the normal list of
+ shared objects, so make sure we pick it up too. Having
+ symbol information for the dynamic linker is quite crucial
+ for skipping dynamic linker resolver code. */
+ lm = solib_svr4_r_ldsomap (info);
+ if (lm)
+ svr4_read_so_list (info, lm, 0, &link_ptr, 0);
+
+ cleanup.release ();
+
+ if (head == NULL)
+ return svr4_default_sos (info);
+
+ return head;
+}
+
+/* Implement the main part of the "current_sos" target_so_ops
+ method. */
+
+static struct so_list *
+svr4_current_sos_1 (svr4_info *info)
+{
+ /* If the solib list has been read and stored by the probes
+ interface then we return a copy of the stored list. */
+ if (info->solib_list != NULL)
+ return svr4_copy_library_list (info->solib_list);
+
+ /* Otherwise obtain the solib list directly from the inferior. */
+ return svr4_current_sos_direct (info);
+}
+
+/* Implement the "current_sos" target_so_ops method. */
+
+static struct so_list *
+svr4_current_sos (void)
+{
+ svr4_info *info = get_svr4_info (current_program_space);
+ struct so_list *so_head = svr4_current_sos_1 (info);
+ struct mem_range vsyscall_range;
+
+ /* Filter out the vDSO module, if present. Its symbol file would
+ not be found on disk. The vDSO/vsyscall's OBJFILE is instead
+ managed by symfile-mem.c:add_vsyscall_page. */
+ if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range)
+ && vsyscall_range.length != 0)
+ {
+ struct so_list **sop;
+
+ sop = &so_head;
+ while (*sop != NULL)
+ {
+ struct so_list *so = *sop;
+
+ /* We can't simply match the vDSO by starting address alone,
+ because lm_info->l_addr_inferior (and also l_addr) do not
+ necessarily represent the real starting address of the
+ ELF if the vDSO's ELF itself is "prelinked". The l_ld
+ field (the ".dynamic" section of the shared object)
+ always points at the absolute/resolved address though.
+ So check whether that address is inside the vDSO's
+ mapping instead.
+
+ E.g., on Linux 3.16 (x86_64) the vDSO is a regular
+ 0-based ELF, and we see:
+
+ (gdb) info auxv
+ 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000
+ (gdb) p/x *_r_debug.r_map.l_next
+ $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...}
+
+ And on Linux 2.6.32 (x86_64) we see:
+
+ (gdb) info auxv
+ 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000
+ (gdb) p/x *_r_debug.r_map.l_next
+ $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... }
+
+ Dumping that vDSO shows:
+
+ (gdb) info proc mappings
+ 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso]
+ (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000
+ # readelf -Wa vdso.bin
+ [...]
+ Entry point address: 0xffffffffff700700
+ [...]
+ Section Headers:
+ [Nr] Name Type Address Off Size
+ [ 0] NULL 0000000000000000 000000 000000
+ [ 1] .hash HASH ffffffffff700120 000120 000038
+ [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8
+ [...]
+ [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0
+ */
+
+ lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info;
+
+ if (address_in_mem_range (li->l_ld, &vsyscall_range))
+ {
+ *sop = so->next;
+ free_so (so);
+ break;
+ }
+
+ sop = &so->next;
+ }
+ }
+
+ return so_head;
+}
+
+/* Get the address of the link_map for a given OBJFILE. */
+
+CORE_ADDR
+svr4_fetch_objfile_link_map (struct objfile *objfile)
+{
+ struct so_list *so;
+ struct svr4_info *info = get_svr4_info (objfile->pspace);
+
+ /* Cause svr4_current_sos() to be run if it hasn't been already. */
+ if (info->main_lm_addr == 0)
+ solib_add (NULL, 0, auto_solib_add);
+
+ /* svr4_current_sos() will set main_lm_addr for the main executable. */
+ if (objfile == symfile_objfile)
+ return info->main_lm_addr;
+
+ /* If OBJFILE is a separate debug object file, look for the
+ original object file. */
+ if (objfile->separate_debug_objfile_backlink != NULL)
+ objfile = objfile->separate_debug_objfile_backlink;
+
+ /* The other link map addresses may be found by examining the list
+ of shared libraries. */
+ for (so = master_so_list (); so; so = so->next)
+ if (so->objfile == objfile)
+ {
+ lm_info_svr4 *li = (lm_info_svr4 *) so->lm_info;
+
+ return li->lm_addr;
+ }
+
+ /* Not found! */
+ return 0;
+}
+
+/* On some systems, the only way to recognize the link map entry for
+ the main executable file is by looking at its name. Return
+ non-zero iff SONAME matches one of the known main executable names. */
+
+static int
+match_main (const char *soname)
+{
+ const char * const *mainp;
+
+ for (mainp = main_name_list; *mainp != NULL; mainp++)
+ {
+ if (strcmp (soname, *mainp) == 0)
+ return (1);
+ }
+
+ return (0);
+}
+
+/* Return 1 if PC lies in the dynamic symbol resolution code of the
+ SVR4 run time loader. */
+
+int
+svr4_in_dynsym_resolve_code (CORE_ADDR pc)
+{
+ struct svr4_info *info = get_svr4_info (current_program_space);
+
+ return ((pc >= info->interp_text_sect_low
+ && pc < info->interp_text_sect_high)
+ || (pc >= info->interp_plt_sect_low
+ && pc < info->interp_plt_sect_high)
+ || in_plt_section (pc)
+ || in_gnu_ifunc_stub (pc));
+}
+
+/* Given an executable's ABFD and target, compute the entry-point
+ address. */
+
+static CORE_ADDR
+exec_entry_point (struct bfd *abfd, struct target_ops *targ)
+{
+ CORE_ADDR addr;
+
+ /* KevinB wrote ... for most targets, the address returned by
+ bfd_get_start_address() is the entry point for the start
+ function. But, for some targets, bfd_get_start_address() returns
+ the address of a function descriptor from which the entry point
+ address may be extracted. This address is extracted by
+ gdbarch_convert_from_func_ptr_addr(). The method
+ gdbarch_convert_from_func_ptr_addr() is the merely the identify
+ function for targets which don't use function descriptors. */
+ addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
+ bfd_get_start_address (abfd),
+ targ);
+ return gdbarch_addr_bits_remove (target_gdbarch (), addr);
+}
+
+/* A probe and its associated action. */
+
+struct probe_and_action
+{
+ /* The probe. */
+ probe *prob;
+
+ /* The relocated address of the probe. */
+ CORE_ADDR address;
+
+ /* The action. */
+ enum probe_action action;
+
+ /* The objfile where this probe was found. */
+ struct objfile *objfile;
+};
+
+/* Returns a hash code for the probe_and_action referenced by p. */
+
+static hashval_t
+hash_probe_and_action (const void *p)
+{
+ const struct probe_and_action *pa = (const struct probe_and_action *) p;
+
+ return (hashval_t) pa->address;
+}
+
+/* Returns non-zero if the probe_and_actions referenced by p1 and p2
+ are equal. */
+
+static int
+equal_probe_and_action (const void *p1, const void *p2)
+{
+ const struct probe_and_action *pa1 = (const struct probe_and_action *) p1;
+ const struct probe_and_action *pa2 = (const struct probe_and_action *) p2;
+
+ return pa1->address == pa2->address;
+}
+
+/* Traversal function for probes_table_remove_objfile_probes. */
+
+static int
+probes_table_htab_remove_objfile_probes (void **slot, void *info)
+{
+ probe_and_action *pa = (probe_and_action *) *slot;
+ struct objfile *objfile = (struct objfile *) info;
+
+ if (pa->objfile == objfile)
+ htab_clear_slot (get_svr4_info (objfile->pspace)->probes_table.get (),
+ slot);
+
+ return 1;
+}
+
+/* Remove all probes that belong to OBJFILE from the probes table. */
+
+static void
+probes_table_remove_objfile_probes (struct objfile *objfile)
+{
+ svr4_info *info = get_svr4_info (objfile->pspace);
+ if (info->probes_table != nullptr)
+ htab_traverse_noresize (info->probes_table.get (),
+ probes_table_htab_remove_objfile_probes, objfile);
+}
+
+/* Register a solib event probe and its associated action in the
+ probes table. */
+
+static void
+register_solib_event_probe (svr4_info *info, struct objfile *objfile,
+ probe *prob, CORE_ADDR address,
+ enum probe_action action)
+{
+ struct probe_and_action lookup, *pa;
+ void **slot;
+
+ /* Create the probes table, if necessary. */
+ if (info->probes_table == NULL)
+ info->probes_table.reset (htab_create_alloc (1, hash_probe_and_action,
+ equal_probe_and_action,
+ xfree, xcalloc, xfree));
+
+ lookup.address = address;
+ slot = htab_find_slot (info->probes_table.get (), &lookup, INSERT);
+ gdb_assert (*slot == HTAB_EMPTY_ENTRY);
+
+ pa = XCNEW (struct probe_and_action);
+ pa->prob = prob;
+ pa->address = address;
+ pa->action = action;
+ pa->objfile = objfile;
+
+ *slot = pa;
+}
+
+/* Get the solib event probe at the specified location, and the
+ action associated with it. Returns NULL if no solib event probe
+ was found. */
+
+static struct probe_and_action *
+solib_event_probe_at (struct svr4_info *info, CORE_ADDR address)
+{
+ struct probe_and_action lookup;
+ void **slot;
+
+ lookup.address = address;
+ slot = htab_find_slot (info->probes_table.get (), &lookup, NO_INSERT);
+
+ if (slot == NULL)
+ return NULL;
+
+ return (struct probe_and_action *) *slot;
+}
+
+/* Decide what action to take when the specified solib event probe is
+ hit. */
+
+static enum probe_action
+solib_event_probe_action (struct probe_and_action *pa)
+{
+ enum probe_action action;
+ unsigned probe_argc = 0;
+ struct frame_info *frame = get_current_frame ();
+
+ action = pa->action;
+ if (action == DO_NOTHING || action == PROBES_INTERFACE_FAILED)
+ return action;
+
+ gdb_assert (action == FULL_RELOAD || action == UPDATE_OR_RELOAD);
+
+ /* Check that an appropriate number of arguments has been supplied.
+ We expect:
+ arg0: Lmid_t lmid (mandatory)
+ arg1: struct r_debug *debug_base (mandatory)
+ arg2: struct link_map *new (optional, for incremental updates) */
+ try
+ {
+ probe_argc = pa->prob->get_argument_count (get_frame_arch (frame));
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ exception_print (gdb_stderr, ex);
+ probe_argc = 0;
+ }
+
+ /* If get_argument_count throws an exception, probe_argc will be set
+ to zero. However, if pa->prob does not have arguments, then
+ get_argument_count will succeed but probe_argc will also be zero.
+ Both cases happen because of different things, but they are
+ treated equally here: action will be set to
+ PROBES_INTERFACE_FAILED. */
+ if (probe_argc == 2)
+ action = FULL_RELOAD;
+ else if (probe_argc < 2)
+ action = PROBES_INTERFACE_FAILED;
+
+ return action;
+}
+
+/* Populate the shared object list by reading the entire list of
+ shared objects from the inferior. Handle special cases relating
+ to the first elements of the list. Returns nonzero on success. */
+
+static int
+solist_update_full (struct svr4_info *info)
+{
+ free_solib_list (info);
+ info->solib_list = svr4_current_sos_direct (info);
+
+ return 1;
+}
+
+/* Update the shared object list starting from the link-map entry
+ passed by the linker in the probe's third argument. Returns
+ nonzero if the list was successfully updated, or zero to indicate
+ failure. */
+
+static int
+solist_update_incremental (struct svr4_info *info, CORE_ADDR lm)
+{
+ struct so_list *tail;
+ CORE_ADDR prev_lm;
+
+ /* svr4_current_sos_direct contains logic to handle a number of
+ special cases relating to the first elements of the list. To
+ avoid duplicating this logic we defer to solist_update_full
+ if the list is empty. */
+ if (info->solib_list == NULL)
+ return 0;
+
+ /* Fall back to a full update if we are using a remote target
+ that does not support incremental transfers. */
+ if (info->using_xfer && !target_augmented_libraries_svr4_read ())
+ return 0;
+
+ /* Walk to the end of the list. */
+ for (tail = info->solib_list; tail->next != NULL; tail = tail->next)
+ /* Nothing. */;
+
+ lm_info_svr4 *li = (lm_info_svr4 *) tail->lm_info;
+ prev_lm = li->lm_addr;
+
+ /* Read the new objects. */
+ if (info->using_xfer)
+ {
+ struct svr4_library_list library_list;
+ char annex[64];
+
+ xsnprintf (annex, sizeof (annex), "start=%s;prev=%s",
+ phex_nz (lm, sizeof (lm)),
+ phex_nz (prev_lm, sizeof (prev_lm)));
+ if (!svr4_current_sos_via_xfer_libraries (&library_list, annex))
+ return 0;
+
+ tail->next = library_list.head;
}
+ else
+ {
+ struct so_list **link = &tail->next;
- /* Have a pathname: read the symbol file. */
- symbol_file_add_main (filename, from_tty);
+ /* IGNORE_FIRST may safely be set to zero here because the
+ above check and deferral to solist_update_full ensures
+ that this call to svr4_read_so_list will never see the
+ first element. */
+ if (!svr4_read_so_list (info, lm, prev_lm, &link, 0))
+ return 0;
+ }
return 1;
}
-/* If no shared library information is available from the dynamic
- linker, build a fallback list from other sources. */
+/* Disable the probes-based linker interface and revert to the
+ original interface. We don't reset the breakpoints as the
+ ones set up for the probes-based interface are adequate. */
-static struct so_list *
-svr4_default_sos (void)
+static void
+disable_probes_interface (svr4_info *info)
{
- struct so_list *head = NULL;
- struct so_list **link_ptr = &head;
+ warning (_("Probes-based dynamic linker interface failed.\n"
+ "Reverting to original interface."));
- if (debug_loader_offset_p)
- {
- struct so_list *new = XZALLOC (struct so_list);
-
- new->lm_info = xmalloc (sizeof (struct lm_info));
+ free_probes_table (info);
+ free_solib_list (info);
+}
- /* Nothing will ever check the cached copy of the link
- map if we set l_addr. */
- new->lm_info->l_addr = debug_loader_offset;
- new->lm_info->lm_addr = 0;
- new->lm_info->lm = NULL;
+/* Update the solib list as appropriate when using the
+ probes-based linker interface. Do nothing if using the
+ standard interface. */
- strncpy (new->so_name, debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1);
- new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
- strcpy (new->so_original_name, new->so_name);
+static void
+svr4_handle_solib_event (void)
+{
+ struct svr4_info *info = get_svr4_info (current_program_space);
+ struct probe_and_action *pa;
+ enum probe_action action;
+ struct value *val = NULL;
+ CORE_ADDR pc, debug_base, lm = 0;
+ struct frame_info *frame = get_current_frame ();
+
+ /* Do nothing if not using the probes interface. */
+ if (info->probes_table == NULL)
+ return;
- *link_ptr = new;
- link_ptr = &new->next;
- }
+ /* If anything goes wrong we revert to the original linker
+ interface. */
+ auto cleanup = make_scope_exit ([info] ()
+ {
+ disable_probes_interface (info);
+ });
- return head;
-}
+ pc = regcache_read_pc (get_current_regcache ());
+ pa = solib_event_probe_at (info, pc);
+ if (pa == NULL)
+ return;
-/* LOCAL FUNCTION
+ action = solib_event_probe_action (pa);
+ if (action == PROBES_INTERFACE_FAILED)
+ return;
- current_sos -- build a list of currently loaded shared objects
+ if (action == DO_NOTHING)
+ {
+ cleanup.release ();
+ return;
+ }
- SYNOPSIS
+ /* evaluate_argument looks up symbols in the dynamic linker
+ using find_pc_section. find_pc_section is accelerated by a cache
+ called the section map. The section map is invalidated every
+ time a shared library is loaded or unloaded, and if the inferior
+ is generating a lot of shared library events then the section map
+ will be updated every time svr4_handle_solib_event is called.
+ We called find_pc_section in svr4_create_solib_event_breakpoints,
+ so we can guarantee that the dynamic linker's sections are in the
+ section map. We can therefore inhibit section map updates across
+ these calls to evaluate_argument and save a lot of time. */
+ {
+ scoped_restore inhibit_updates
+ = inhibit_section_map_updates (current_program_space);
- struct so_list *current_sos ()
+ try
+ {
+ val = pa->prob->evaluate_argument (1, frame);
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ exception_print (gdb_stderr, ex);
+ val = NULL;
+ }
- DESCRIPTION
+ if (val == NULL)
+ return;
- Build a list of `struct so_list' objects describing the shared
- objects currently loaded in the inferior. This list does not
- include an entry for the main executable file.
+ debug_base = value_as_address (val);
+ if (debug_base == 0)
+ return;
- Note that we only gather information directly available from the
- inferior --- we don't examine any of the shared library files
- themselves. The declaration of `struct so_list' says which fields
- we provide values for. */
+ /* Always locate the debug struct, in case it moved. */
+ info->debug_base = 0;
+ if (locate_base (info) == 0)
+ return;
-static struct so_list *
-svr4_current_sos (void)
-{
- CORE_ADDR lm;
- struct so_list *head = 0;
- struct so_list **link_ptr = &head;
- CORE_ADDR ldsomap = 0;
+ /* GDB does not currently support libraries loaded via dlmopen
+ into namespaces other than the initial one. We must ignore
+ any namespace other than the initial namespace here until
+ support for this is added to GDB. */
+ if (debug_base != info->debug_base)
+ action = DO_NOTHING;
- /* Always locate the debug struct, in case it has moved. */
- debug_base = 0;
- locate_base ();
+ if (action == UPDATE_OR_RELOAD)
+ {
+ try
+ {
+ val = pa->prob->evaluate_argument (2, frame);
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ exception_print (gdb_stderr, ex);
+ return;
+ }
+
+ if (val != NULL)
+ lm = value_as_address (val);
+
+ if (lm == 0)
+ action = FULL_RELOAD;
+ }
- /* If we can't find the dynamic linker's base structure, this
- must not be a dynamically linked executable. Hmm. */
- if (! debug_base)
- return svr4_default_sos ();
+ /* Resume section map updates. Closing the scope is
+ sufficient. */
+ }
- /* Walk the inferior's link map list, and build our list of
- `struct so_list' nodes. */
- lm = solib_svr4_r_map ();
+ if (action == UPDATE_OR_RELOAD)
+ {
+ if (!solist_update_incremental (info, lm))
+ action = FULL_RELOAD;
+ }
- while (lm)
+ if (action == FULL_RELOAD)
{
- struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
- struct so_list *new = XZALLOC (struct so_list);
- struct cleanup *old_chain = make_cleanup (xfree, new);
+ if (!solist_update_full (info))
+ return;
+ }
- new->lm_info = xmalloc (sizeof (struct lm_info));
- make_cleanup (xfree, new->lm_info);
+ cleanup.release ();
+}
- new->lm_info->l_addr = (CORE_ADDR)-1;
- new->lm_info->lm_addr = lm;
- new->lm_info->lm = xzalloc (lmo->link_map_size);
- make_cleanup (xfree, new->lm_info->lm);
+/* Helper function for svr4_update_solib_event_breakpoints. */
- read_memory (lm, new->lm_info->lm, lmo->link_map_size);
+static bool
+svr4_update_solib_event_breakpoint (struct breakpoint *b)
+{
+ struct bp_location *loc;
- lm = LM_NEXT (new);
+ if (b->type != bp_shlib_event)
+ {
+ /* Continue iterating. */
+ return false;
+ }
- /* For SVR4 versions, the first entry in the link map is for the
- inferior executable, so we must ignore it. For some versions of
- SVR4, it has no name. For others (Solaris 2.3 for example), it
- does have a name, so we can no longer use a missing name to
- decide when to ignore it. */
- if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap == 0)
- {
- main_lm_addr = new->lm_info->lm_addr;
- free_so (new);
- }
- else
- {
- int errcode;
- char *buffer;
+ for (loc = b->loc; loc != NULL; loc = loc->next)
+ {
+ struct svr4_info *info;
+ struct probe_and_action *pa;
- /* Extract this shared object's name. */
- target_read_string (LM_NAME (new), &buffer,
- SO_NAME_MAX_PATH_SIZE - 1, &errcode);
- if (errcode != 0)
- warning (_("Can't read pathname for load map: %s."),
- safe_strerror (errcode));
- else
- {
- strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
- new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
- strcpy (new->so_original_name, new->so_name);
- }
- xfree (buffer);
+ info = solib_svr4_pspace_data.get (loc->pspace);
+ if (info == NULL || info->probes_table == NULL)
+ continue;
- /* If this entry has no name, or its name matches the name
- for the main executable, don't include it in the list. */
- if (! new->so_name[0]
- || match_main (new->so_name))
- free_so (new);
- else
- {
- new->next = 0;
- *link_ptr = new;
- link_ptr = &new->next;
- }
- }
+ pa = solib_event_probe_at (info, loc->address);
+ if (pa == NULL)
+ continue;
- /* On Solaris, the dynamic linker is not in the normal list of
- shared objects, so make sure we pick it up too. Having
- symbol information for the dynamic linker is quite crucial
- for skipping dynamic linker resolver code. */
- if (lm == 0 && ldsomap == 0)
- lm = ldsomap = solib_svr4_r_ldsomap ();
+ if (pa->action == DO_NOTHING)
+ {
+ if (b->enable_state == bp_disabled && stop_on_solib_events)
+ enable_breakpoint (b);
+ else if (b->enable_state == bp_enabled && !stop_on_solib_events)
+ disable_breakpoint (b);
+ }
- discard_cleanups (old_chain);
+ break;
}
- if (head == NULL)
- return svr4_default_sos ();
-
- return head;
+ /* Continue iterating. */
+ return false;
}
-/* Get the address of the link_map for a given OBJFILE. */
+/* Enable or disable optional solib event breakpoints as appropriate.
+ Called whenever stop_on_solib_events is changed. */
-CORE_ADDR
-svr4_fetch_objfile_link_map (struct objfile *objfile)
+static void
+svr4_update_solib_event_breakpoints (void)
{
- struct so_list *so;
+ iterate_over_breakpoints (svr4_update_solib_event_breakpoint);
+}
- /* Cause svr4_current_sos() to be run if it hasn't been already. */
- if (main_lm_addr == 0)
- solib_add (NULL, 0, ¤t_target, auto_solib_add);
+/* Create and register solib event breakpoints. PROBES is an array
+ of NUM_PROBES elements, each of which is vector of probes. A
+ solib event breakpoint will be created and registered for each
+ probe. */
- /* svr4_current_sos() will set main_lm_addr for the main executable. */
- if (objfile == symfile_objfile)
- return main_lm_addr;
+static void
+svr4_create_probe_breakpoints (svr4_info *info, struct gdbarch *gdbarch,
+ const std::vector<probe *> *probes,
+ struct objfile *objfile)
+{
+ for (int i = 0; i < NUM_PROBES; i++)
+ {
+ enum probe_action action = probe_info[i].action;
- /* The other link map addresses may be found by examining the list
- of shared libraries. */
- for (so = master_so_list (); so; so = so->next)
- if (so->objfile == objfile)
- return so->lm_info->lm_addr;
+ for (probe *p : probes[i])
+ {
+ CORE_ADDR address = p->get_relocated_address (objfile);
- /* Not found! */
- return 0;
-}
+ create_solib_event_breakpoint (gdbarch, address);
+ register_solib_event_probe (info, objfile, p, address, action);
+ }
+ }
-/* On some systems, the only way to recognize the link map entry for
- the main executable file is by looking at its name. Return
- non-zero iff SONAME matches one of the known main executable names. */
+ svr4_update_solib_event_breakpoints ();
+}
-static int
-match_main (char *soname)
+/* Find all the glibc named probes. Only if all of the probes are found, then
+ create them and return true. Otherwise return false. If WITH_PREFIX is set
+ then add "rtld" to the front of the probe names. */
+static bool
+svr4_find_and_create_probe_breakpoints (svr4_info *info,
+ struct gdbarch *gdbarch,
+ struct obj_section *os,
+ bool with_prefix)
{
- char **mainp;
+ std::vector<probe *> probes[NUM_PROBES];
- for (mainp = main_name_list; *mainp != NULL; mainp++)
+ for (int i = 0; i < NUM_PROBES; i++)
{
- if (strcmp (soname, *mainp) == 0)
- return (1);
- }
+ const char *name = probe_info[i].name;
+ char buf[32];
+
+ /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4 shipped with an early
+ version of the probes code in which the probes' names were prefixed
+ with "rtld_" and the "map_failed" probe did not exist. The locations
+ of the probes are otherwise the same, so we check for probes with
+ prefixed names if probes with unprefixed names are not present. */
+ if (with_prefix)
+ {
+ xsnprintf (buf, sizeof (buf), "rtld_%s", name);
+ name = buf;
+ }
- return (0);
-}
+ probes[i] = find_probes_in_objfile (os->objfile, "rtld", name);
-/* Return 1 if PC lies in the dynamic symbol resolution code of the
- SVR4 run time loader. */
-static CORE_ADDR interp_text_sect_low;
-static CORE_ADDR interp_text_sect_high;
-static CORE_ADDR interp_plt_sect_low;
-static CORE_ADDR interp_plt_sect_high;
+ /* The "map_failed" probe did not exist in early
+ versions of the probes code in which the probes'
+ names were prefixed with "rtld_". */
+ if (with_prefix && streq (name, "rtld_map_failed"))
+ continue;
-int
-svr4_in_dynsym_resolve_code (CORE_ADDR pc)
-{
- return ((pc >= interp_text_sect_low && pc < interp_text_sect_high)
- || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high)
- || in_plt_section (pc, NULL));
-}
+ /* Ensure at least one probe for the current name was found. */
+ if (probes[i].empty ())
+ return false;
-/* Given an executable's ABFD and target, compute the entry-point
- address. */
+ /* Ensure probe arguments can be evaluated. */
+ for (probe *p : probes[i])
+ {
+ if (!p->can_evaluate_arguments ())
+ return false;
+ /* This will fail if the probe is invalid. This has been seen on Arm
+ due to references to symbols that have been resolved away. */
+ try
+ {
+ p->get_argument_count (gdbarch);
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ exception_print (gdb_stderr, ex);
+ warning (_("Initializing probes-based dynamic linker interface "
+ "failed.\nReverting to original interface."));
+ return false;
+ }
+ }
+ }
-static CORE_ADDR
-exec_entry_point (struct bfd *abfd, struct target_ops *targ)
-{
- /* KevinB wrote ... for most targets, the address returned by
- bfd_get_start_address() is the entry point for the start
- function. But, for some targets, bfd_get_start_address() returns
- the address of a function descriptor from which the entry point
- address may be extracted. This address is extracted by
- gdbarch_convert_from_func_ptr_addr(). The method
- gdbarch_convert_from_func_ptr_addr() is the merely the identify
- function for targets which don't use function descriptors. */
- return gdbarch_convert_from_func_ptr_addr (target_gdbarch,
- bfd_get_start_address (abfd),
- targ);
+ /* All probes found. Now create them. */
+ svr4_create_probe_breakpoints (info, gdbarch, probes, os->objfile);
+ return true;
}
-/*
+/* Both the SunOS and the SVR4 dynamic linkers call a marker function
+ before and after mapping and unmapping shared libraries. The sole
+ purpose of this method is to allow debuggers to set a breakpoint so
+ they can track these changes.
- LOCAL FUNCTION
+ Some versions of the glibc dynamic linker contain named probes
+ to allow more fine grained stopping. Given the address of the
+ original marker function, this function attempts to find these
+ probes, and if found, sets breakpoints on those instead. If the
+ probes aren't found, a single breakpoint is set on the original
+ marker function. */
- enable_break -- arrange for dynamic linker to hit breakpoint
+static void
+svr4_create_solib_event_breakpoints (svr4_info *info, struct gdbarch *gdbarch,
+ CORE_ADDR address)
+{
+ struct obj_section *os = find_pc_section (address);
- SYNOPSIS
+ if (os == nullptr
+ || (!svr4_find_and_create_probe_breakpoints (info, gdbarch, os, false)
+ && !svr4_find_and_create_probe_breakpoints (info, gdbarch, os, true)))
+ create_solib_event_breakpoint (gdbarch, address);
+}
- int enable_break (void)
+/* Helper function for gdb_bfd_lookup_symbol. */
- DESCRIPTION
+static int
+cmp_name_and_sec_flags (const asymbol *sym, const void *data)
+{
+ return (strcmp (sym->name, (const char *) data) == 0
+ && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0);
+}
+/* Arrange for dynamic linker to hit breakpoint.
Both the SunOS and the SVR4 dynamic linkers have, as part of their
debugger interface, support for arranging for the inferior to hit
The debugger interface structure also contains an enumeration which
is set to either RT_ADD or RT_DELETE prior to changing the mapping,
depending upon whether or not the library is being mapped or unmapped,
- and then set to RT_CONSISTENT after the library is mapped/unmapped.
- */
+ and then set to RT_CONSISTENT after the library is mapped/unmapped. */
static int
-enable_break (void)
+enable_break (struct svr4_info *info, int from_tty)
{
- struct minimal_symbol *msymbol;
- char **bkpt_namep;
+ struct bound_minimal_symbol msymbol;
+ const char * const *bkpt_namep;
asection *interp_sect;
CORE_ADDR sym_addr;
- /* First, remove all the solib event breakpoints. Their addresses
- may have changed since the last time we ran the program. */
- remove_solib_event_breakpoints ();
-
- interp_text_sect_low = interp_text_sect_high = 0;
- interp_plt_sect_low = interp_plt_sect_high = 0;
+ info->interp_text_sect_low = info->interp_text_sect_high = 0;
+ info->interp_plt_sect_low = info->interp_plt_sect_high = 0;
/* If we already have a shared library list in the target, and
r_debug contains r_brk, set the breakpoint there - this should
mean r_brk has already been relocated. Assume the dynamic linker
is the object containing r_brk. */
- solib_add (NULL, 0, ¤t_target, auto_solib_add);
+ solib_add (NULL, from_tty, auto_solib_add);
sym_addr = 0;
- if (debug_base && solib_svr4_r_map () != 0)
- sym_addr = solib_svr4_r_brk ();
+ if (info->debug_base && solib_svr4_r_map (info) != 0)
+ sym_addr = solib_svr4_r_brk (info);
if (sym_addr != 0)
{
struct obj_section *os;
sym_addr = gdbarch_addr_bits_remove
- (target_gdbarch, gdbarch_convert_from_func_ptr_addr (target_gdbarch,
- sym_addr,
- ¤t_target));
+ (target_gdbarch (),
+ gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
+ sym_addr,
+ current_top_target ()));
+
+ /* On at least some versions of Solaris there's a dynamic relocation
+ on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
+ we get control before the dynamic linker has self-relocated.
+ Check if SYM_ADDR is in a known section, if it is assume we can
+ trust its value. This is just a heuristic though, it could go away
+ or be replaced if it's getting in the way.
+
+ On ARM we need to know whether the ISA of rtld_db_dlactivity (or
+ however it's spelled in your particular system) is ARM or Thumb.
+ That knowledge is encoded in the address, if it's Thumb the low bit
+ is 1. However, we've stripped that info above and it's not clear
+ what all the consequences are of passing a non-addr_bits_remove'd
+ address to svr4_create_solib_event_breakpoints. The call to
+ find_pc_section verifies we know about the address and have some
+ hope of computing the right kind of breakpoint to use (via
+ symbol info). It does mean that GDB needs to be pointed at a
+ non-stripped version of the dynamic linker in order to obtain
+ information it already knows about. Sigh. */
os = find_pc_section (sym_addr);
if (os != NULL)
tmp_bfd = os->objfile->obfd;
load_addr = ANOFFSET (os->objfile->section_offsets,
- os->objfile->sect_index_text);
+ SECT_OFF_TEXT (os->objfile));
interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
if (interp_sect)
{
- interp_text_sect_low =
- bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
- interp_text_sect_high =
- interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+ info->interp_text_sect_low
+ = bfd_section_vma (interp_sect) + load_addr;
+ info->interp_text_sect_high
+ = info->interp_text_sect_low + bfd_section_size (interp_sect);
}
interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
if (interp_sect)
{
- interp_plt_sect_low =
- bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
- interp_plt_sect_high =
- interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+ info->interp_plt_sect_low
+ = bfd_section_vma (interp_sect) + load_addr;
+ info->interp_plt_sect_high
+ = info->interp_plt_sect_low + bfd_section_size (interp_sect);
}
- create_solib_event_breakpoint (sym_addr);
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (), sym_addr);
return 1;
}
}
- /* Find the .interp section; if not found, warn the user and drop
+ /* Find the program interpreter; if not found, warn the user and drop
into the old breakpoint at symbol code. */
- interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
- if (interp_sect)
+ gdb::optional<gdb::byte_vector> interp_name_holder
+ = find_program_interpreter ();
+ if (interp_name_holder)
{
- unsigned int interp_sect_size;
- char *buf;
+ const char *interp_name = (const char *) interp_name_holder->data ();
CORE_ADDR load_addr = 0;
int load_addr_found = 0;
int loader_found_in_list = 0;
struct so_list *so;
- bfd *tmp_bfd = NULL;
struct target_ops *tmp_bfd_target;
- volatile struct gdb_exception ex;
- /* Read the contents of the .interp section into a local buffer;
- the contents specify the dynamic linker this program uses. */
sym_addr = 0;
- interp_sect_size = bfd_section_size (exec_bfd, interp_sect);
- buf = alloca (interp_sect_size);
- bfd_get_section_contents (exec_bfd, interp_sect,
- buf, 0, interp_sect_size);
/* Now we need to figure out where the dynamic linker was
loaded so that we can load its symbols and place a breakpoint
be trivial on GNU/Linux). Therefore, we have to try an alternate
mechanism to find the dynamic linker's base address. */
- TRY_CATCH (ex, RETURN_MASK_ALL)
+ gdb_bfd_ref_ptr tmp_bfd;
+ try
{
- tmp_bfd = solib_bfd_open (buf);
+ tmp_bfd = solib_bfd_open (interp_name);
}
+ catch (const gdb_exception &ex)
+ {
+ }
+
if (tmp_bfd == NULL)
goto bkpt_at_symbol;
/* Now convert the TMP_BFD into a target. That way target, as
- well as BFD operations can be used. Note that closing the
- target will also close the underlying bfd. */
- tmp_bfd_target = target_bfd_reopen (tmp_bfd);
+ well as BFD operations can be used. target_bfd_reopen
+ acquires its own reference. */
+ tmp_bfd_target = target_bfd_reopen (tmp_bfd.get ());
/* On a running target, we can get the dynamic linker's base
address from the shared library table. */
so = master_so_list ();
while (so)
{
- if (svr4_same_1 (buf, so->so_original_name))
+ if (svr4_same_1 (interp_name, so->so_original_name))
{
load_addr_found = 1;
loader_found_in_list = 1;
- load_addr = LM_ADDR_CHECK (so, tmp_bfd);
+ load_addr = lm_addr_check (so, tmp_bfd.get ());
break;
}
so = so->next;
/* If we were not able to find the base address of the loader
from our so_list, then try using the AT_BASE auxilliary entry. */
if (!load_addr_found)
- if (target_auxv_search (¤t_target, AT_BASE, &load_addr) > 0)
- load_addr_found = 1;
+ if (target_auxv_search (current_top_target (), AT_BASE, &load_addr) > 0)
+ {
+ int addr_bit = gdbarch_addr_bit (target_gdbarch ());
+
+ /* Ensure LOAD_ADDR has proper sign in its possible upper bits so
+ that `+ load_addr' will overflow CORE_ADDR width not creating
+ invalid addresses like 0x101234567 for 32bit inferiors on 64bit
+ GDB. */
+
+ if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))
+ {
+ CORE_ADDR space_size = (CORE_ADDR) 1 << addr_bit;
+ CORE_ADDR tmp_entry_point = exec_entry_point (tmp_bfd.get (),
+ tmp_bfd_target);
+
+ gdb_assert (load_addr < space_size);
+
+ /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked
+ 64bit ld.so with 32bit executable, it should not happen. */
+
+ if (tmp_entry_point < space_size
+ && tmp_entry_point + load_addr >= space_size)
+ load_addr -= space_size;
+ }
+
+ load_addr_found = 1;
+ }
/* Otherwise we find the dynamic linker's base address by examining
the current pc (which should point at the entry point for the
fallback method because it has actually been working well in
most cases. */
if (!load_addr_found)
- load_addr = (read_pc ()
- - exec_entry_point (tmp_bfd, tmp_bfd_target));
+ {
+ struct regcache *regcache
+ = get_thread_arch_regcache (inferior_ptid, target_gdbarch ());
+
+ load_addr = (regcache_read_pc (regcache)
+ - exec_entry_point (tmp_bfd.get (), tmp_bfd_target));
+ }
if (!loader_found_in_list)
{
- debug_loader_name = xstrdup (buf);
- debug_loader_offset_p = 1;
- debug_loader_offset = load_addr;
- solib_add (NULL, 0, ¤t_target, auto_solib_add);
+ info->debug_loader_name = xstrdup (interp_name);
+ info->debug_loader_offset_p = 1;
+ info->debug_loader_offset = load_addr;
+ solib_add (NULL, from_tty, auto_solib_add);
}
/* Record the relocated start and end address of the dynamic linker
text and plt section for svr4_in_dynsym_resolve_code. */
- interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
+ interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".text");
if (interp_sect)
{
- interp_text_sect_low =
- bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
- interp_text_sect_high =
- interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+ info->interp_text_sect_low
+ = bfd_section_vma (interp_sect) + load_addr;
+ info->interp_text_sect_high
+ = info->interp_text_sect_low + bfd_section_size (interp_sect);
}
- interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
+ interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".plt");
if (interp_sect)
{
- interp_plt_sect_low =
- bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
- interp_plt_sect_high =
- interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+ info->interp_plt_sect_low
+ = bfd_section_vma (interp_sect) + load_addr;
+ info->interp_plt_sect_high
+ = info->interp_plt_sect_low + bfd_section_size (interp_sect);
}
/* Now try to set a breakpoint in the dynamic linker. */
for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
{
- sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep);
+ sym_addr = gdb_bfd_lookup_symbol (tmp_bfd.get (),
+ cmp_name_and_sec_flags,
+ *bkpt_namep);
if (sym_addr != 0)
break;
}
/* Convert 'sym_addr' from a function pointer to an address.
Because we pass tmp_bfd_target instead of the current
target, this will always produce an unrelocated value. */
- sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch,
+ sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
sym_addr,
tmp_bfd_target);
- /* We're done with both the temporary bfd and target. Remember,
- closing the target closes the underlying bfd. */
- target_close (tmp_bfd_target, 0);
+ /* We're done with both the temporary bfd and target. Closing
+ the target closes the underlying bfd, because it holds the
+ only remaining reference. */
+ target_close (tmp_bfd_target);
if (sym_addr != 0)
{
- create_solib_event_breakpoint (load_addr + sym_addr);
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (),
+ load_addr + sym_addr);
return 1;
}
for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
{
msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
- if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
+ if ((msymbol.minsym != NULL)
+ && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0))
{
- create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
+ sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
+ sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
+ sym_addr,
+ current_top_target ());
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (),
+ sym_addr);
return 1;
}
}
- for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
+ if (interp_name_holder && !current_inferior ()->attach_flag)
{
- msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
- if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
+ for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
{
- create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
- return 1;
+ msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
+ if ((msymbol.minsym != NULL)
+ && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0))
+ {
+ sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
+ sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
+ sym_addr,
+ current_top_target ());
+ svr4_create_solib_event_breakpoints (info, target_gdbarch (),
+ sym_addr);
+ return 1;
+ }
}
}
return 0;
}
-/*
+/* Read the ELF program headers from ABFD. */
- LOCAL FUNCTION
+static gdb::optional<gdb::byte_vector>
+read_program_headers_from_bfd (bfd *abfd)
+{
+ Elf_Internal_Ehdr *ehdr = elf_elfheader (abfd);
+ int phdrs_size = ehdr->e_phnum * ehdr->e_phentsize;
+ if (phdrs_size == 0)
+ return {};
+
+ gdb::byte_vector buf (phdrs_size);
+ if (bfd_seek (abfd, ehdr->e_phoff, SEEK_SET) != 0
+ || bfd_bread (buf.data (), phdrs_size, abfd) != phdrs_size)
+ return {};
+
+ return buf;
+}
- special_symbol_handling -- additional shared library symbol handling
+/* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior
+ exec_bfd. Otherwise return 0.
+
+ We relocate all of the sections by the same amount. This
+ behavior is mandated by recent editions of the System V ABI.
+ According to the System V Application Binary Interface,
+ Edition 4.1, page 5-5:
+
+ ... Though the system chooses virtual addresses for
+ individual processes, it maintains the segments' relative
+ positions. Because position-independent code uses relative
+ addressing between segments, the difference between
+ virtual addresses in memory must match the difference
+ between virtual addresses in the file. The difference
+ between the virtual address of any segment in memory and
+ the corresponding virtual address in the file is thus a
+ single constant value for any one executable or shared
+ object in a given process. This difference is the base
+ address. One use of the base address is to relocate the
+ memory image of the program during dynamic linking.
+
+ The same language also appears in Edition 4.0 of the System V
+ ABI and is left unspecified in some of the earlier editions.
+
+ Decide if the objfile needs to be relocated. As indicated above, we will
+ only be here when execution is stopped. But during attachment PC can be at
+ arbitrary address therefore regcache_read_pc can be misleading (contrary to
+ the auxv AT_ENTRY value). Moreover for executable with interpreter section
+ regcache_read_pc would point to the interpreter and not the main executable.
+
+ So, to summarize, relocations are necessary when the start address obtained
+ from the executable is different from the address in auxv AT_ENTRY entry.
+
+ [ The astute reader will note that we also test to make sure that
+ the executable in question has the DYNAMIC flag set. It is my
+ opinion that this test is unnecessary (undesirable even). It
+ was added to avoid inadvertent relocation of an executable
+ whose e_type member in the ELF header is not ET_DYN. There may
+ be a time in the future when it is desirable to do relocations
+ on other types of files as well in which case this condition
+ should either be removed or modified to accomodate the new file
+ type. - Kevin, Nov 2000. ] */
- SYNOPSIS
+static int
+svr4_exec_displacement (CORE_ADDR *displacementp)
+{
+ /* ENTRY_POINT is a possible function descriptor - before
+ a call to gdbarch_convert_from_func_ptr_addr. */
+ CORE_ADDR entry_point, exec_displacement;
- void special_symbol_handling ()
+ if (exec_bfd == NULL)
+ return 0;
- DESCRIPTION
+ /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries
+ being executed themselves and PIE (Position Independent Executable)
+ executables are ET_DYN. */
- Once the symbols from a shared object have been loaded in the usual
- way, we are called to do any system specific symbol handling that
- is needed.
+ if ((bfd_get_file_flags (exec_bfd) & DYNAMIC) == 0)
+ return 0;
- For SunOS4, this consisted of grunging around in the dynamic
- linkers structures to find symbol definitions for "common" symbols
- and adding them to the minimal symbol table for the runtime common
- objfile.
+ if (target_auxv_search (current_top_target (), AT_ENTRY, &entry_point) <= 0)
+ return 0;
- However, for SVR4, there's nothing to do.
+ exec_displacement = entry_point - bfd_get_start_address (exec_bfd);
- */
+ /* Verify the EXEC_DISPLACEMENT candidate complies with the required page
+ alignment. It is cheaper than the program headers comparison below. */
-static void
-svr4_special_symbol_handling (void)
-{
+ if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
+ {
+ const struct elf_backend_data *elf = get_elf_backend_data (exec_bfd);
+
+ /* p_align of PT_LOAD segments does not specify any alignment but
+ only congruency of addresses:
+ p_offset % p_align == p_vaddr % p_align
+ Kernel is free to load the executable with lower alignment. */
+
+ if ((exec_displacement & (elf->minpagesize - 1)) != 0)
+ return 0;
+ }
+
+ /* Verify that the auxilliary vector describes the same file as exec_bfd, by
+ comparing their program headers. If the program headers in the auxilliary
+ vector do not match the program headers in the executable, then we are
+ looking at a different file than the one used by the kernel - for
+ instance, "gdb program" connected to "gdbserver :PORT ld.so program". */
+
+ if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
+ {
+ /* Be optimistic and return 0 only if GDB was able to verify the headers
+ really do not match. */
+ int arch_size;
+
+ gdb::optional<gdb::byte_vector> phdrs_target
+ = read_program_header (-1, &arch_size, NULL);
+ gdb::optional<gdb::byte_vector> phdrs_binary
+ = read_program_headers_from_bfd (exec_bfd);
+ if (phdrs_target && phdrs_binary)
+ {
+ enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
+
+ /* We are dealing with three different addresses. EXEC_BFD
+ represents current address in on-disk file. target memory content
+ may be different from EXEC_BFD as the file may have been prelinked
+ to a different address after the executable has been loaded.
+ Moreover the address of placement in target memory can be
+ different from what the program headers in target memory say -
+ this is the goal of PIE.
+
+ Detected DISPLACEMENT covers both the offsets of PIE placement and
+ possible new prelink performed after start of the program. Here
+ relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
+ content offset for the verification purpose. */
+
+ if (phdrs_target->size () != phdrs_binary->size ()
+ || bfd_get_arch_size (exec_bfd) != arch_size)
+ return 0;
+ else if (arch_size == 32
+ && phdrs_target->size () >= sizeof (Elf32_External_Phdr)
+ && phdrs_target->size () % sizeof (Elf32_External_Phdr) == 0)
+ {
+ Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header;
+ Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr;
+ CORE_ADDR displacement = 0;
+ int i;
+
+ /* DISPLACEMENT could be found more easily by the difference of
+ ehdr2->e_entry. But we haven't read the ehdr yet, and we
+ already have enough information to compute that displacement
+ with what we've read. */
+
+ for (i = 0; i < ehdr2->e_phnum; i++)
+ if (phdr2[i].p_type == PT_LOAD)
+ {
+ Elf32_External_Phdr *phdrp;
+ gdb_byte *buf_vaddr_p, *buf_paddr_p;
+ CORE_ADDR vaddr, paddr;
+ CORE_ADDR displacement_vaddr = 0;
+ CORE_ADDR displacement_paddr = 0;
+
+ phdrp = &((Elf32_External_Phdr *) phdrs_target->data ())[i];
+ buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
+ buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
+
+ vaddr = extract_unsigned_integer (buf_vaddr_p, 4,
+ byte_order);
+ displacement_vaddr = vaddr - phdr2[i].p_vaddr;
+
+ paddr = extract_unsigned_integer (buf_paddr_p, 4,
+ byte_order);
+ displacement_paddr = paddr - phdr2[i].p_paddr;
+
+ if (displacement_vaddr == displacement_paddr)
+ displacement = displacement_vaddr;
+
+ break;
+ }
+
+ /* Now compare program headers from the target and the binary
+ with optional DISPLACEMENT. */
+
+ for (i = 0;
+ i < phdrs_target->size () / sizeof (Elf32_External_Phdr);
+ i++)
+ {
+ Elf32_External_Phdr *phdrp;
+ Elf32_External_Phdr *phdr2p;
+ gdb_byte *buf_vaddr_p, *buf_paddr_p;
+ CORE_ADDR vaddr, paddr;
+ asection *plt2_asect;
+
+ phdrp = &((Elf32_External_Phdr *) phdrs_target->data ())[i];
+ buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
+ buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
+ phdr2p = &((Elf32_External_Phdr *) phdrs_binary->data ())[i];
+
+ /* PT_GNU_STACK is an exception by being never relocated by
+ prelink as its addresses are always zero. */
+
+ if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
+ continue;
+
+ /* Check also other adjustment combinations - PR 11786. */
+
+ vaddr = extract_unsigned_integer (buf_vaddr_p, 4,
+ byte_order);
+ vaddr -= displacement;
+ store_unsigned_integer (buf_vaddr_p, 4, byte_order, vaddr);
+
+ paddr = extract_unsigned_integer (buf_paddr_p, 4,
+ byte_order);
+ paddr -= displacement;
+ store_unsigned_integer (buf_paddr_p, 4, byte_order, paddr);
+
+ if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
+ continue;
+
+ /* Strip modifies the flags and alignment of PT_GNU_RELRO.
+ CentOS-5 has problems with filesz, memsz as well.
+ Strip also modifies memsz of PT_TLS.
+ See PR 11786. */
+ if (phdr2[i].p_type == PT_GNU_RELRO
+ || phdr2[i].p_type == PT_TLS)
+ {
+ Elf32_External_Phdr tmp_phdr = *phdrp;
+ Elf32_External_Phdr tmp_phdr2 = *phdr2p;
+
+ memset (tmp_phdr.p_filesz, 0, 4);
+ memset (tmp_phdr.p_memsz, 0, 4);
+ memset (tmp_phdr.p_flags, 0, 4);
+ memset (tmp_phdr.p_align, 0, 4);
+ memset (tmp_phdr2.p_filesz, 0, 4);
+ memset (tmp_phdr2.p_memsz, 0, 4);
+ memset (tmp_phdr2.p_flags, 0, 4);
+ memset (tmp_phdr2.p_align, 0, 4);
+
+ if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr))
+ == 0)
+ continue;
+ }
+
+ /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
+ plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt");
+ if (plt2_asect)
+ {
+ int content2;
+ gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz;
+ CORE_ADDR filesz;
+
+ content2 = (bfd_section_flags (plt2_asect)
+ & SEC_HAS_CONTENTS) != 0;
+
+ filesz = extract_unsigned_integer (buf_filesz_p, 4,
+ byte_order);
+
+ /* PLT2_ASECT is from on-disk file (exec_bfd) while
+ FILESZ is from the in-memory image. */
+ if (content2)
+ filesz += bfd_section_size (plt2_asect);
+ else
+ filesz -= bfd_section_size (plt2_asect);
+
+ store_unsigned_integer (buf_filesz_p, 4, byte_order,
+ filesz);
+
+ if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
+ continue;
+ }
+
+ return 0;
+ }
+ }
+ else if (arch_size == 64
+ && phdrs_target->size () >= sizeof (Elf64_External_Phdr)
+ && phdrs_target->size () % sizeof (Elf64_External_Phdr) == 0)
+ {
+ Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header;
+ Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr;
+ CORE_ADDR displacement = 0;
+ int i;
+
+ /* DISPLACEMENT could be found more easily by the difference of
+ ehdr2->e_entry. But we haven't read the ehdr yet, and we
+ already have enough information to compute that displacement
+ with what we've read. */
+
+ for (i = 0; i < ehdr2->e_phnum; i++)
+ if (phdr2[i].p_type == PT_LOAD)
+ {
+ Elf64_External_Phdr *phdrp;
+ gdb_byte *buf_vaddr_p, *buf_paddr_p;
+ CORE_ADDR vaddr, paddr;
+ CORE_ADDR displacement_vaddr = 0;
+ CORE_ADDR displacement_paddr = 0;
+
+ phdrp = &((Elf64_External_Phdr *) phdrs_target->data ())[i];
+ buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
+ buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
+
+ vaddr = extract_unsigned_integer (buf_vaddr_p, 8,
+ byte_order);
+ displacement_vaddr = vaddr - phdr2[i].p_vaddr;
+
+ paddr = extract_unsigned_integer (buf_paddr_p, 8,
+ byte_order);
+ displacement_paddr = paddr - phdr2[i].p_paddr;
+
+ if (displacement_vaddr == displacement_paddr)
+ displacement = displacement_vaddr;
+
+ break;
+ }
+
+ /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
+
+ for (i = 0;
+ i < phdrs_target->size () / sizeof (Elf64_External_Phdr);
+ i++)
+ {
+ Elf64_External_Phdr *phdrp;
+ Elf64_External_Phdr *phdr2p;
+ gdb_byte *buf_vaddr_p, *buf_paddr_p;
+ CORE_ADDR vaddr, paddr;
+ asection *plt2_asect;
+
+ phdrp = &((Elf64_External_Phdr *) phdrs_target->data ())[i];
+ buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
+ buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
+ phdr2p = &((Elf64_External_Phdr *) phdrs_binary->data ())[i];
+
+ /* PT_GNU_STACK is an exception by being never relocated by
+ prelink as its addresses are always zero. */
+
+ if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
+ continue;
+
+ /* Check also other adjustment combinations - PR 11786. */
+
+ vaddr = extract_unsigned_integer (buf_vaddr_p, 8,
+ byte_order);
+ vaddr -= displacement;
+ store_unsigned_integer (buf_vaddr_p, 8, byte_order, vaddr);
+
+ paddr = extract_unsigned_integer (buf_paddr_p, 8,
+ byte_order);
+ paddr -= displacement;
+ store_unsigned_integer (buf_paddr_p, 8, byte_order, paddr);
+
+ if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
+ continue;
+
+ /* Strip modifies the flags and alignment of PT_GNU_RELRO.
+ CentOS-5 has problems with filesz, memsz as well.
+ Strip also modifies memsz of PT_TLS.
+ See PR 11786. */
+ if (phdr2[i].p_type == PT_GNU_RELRO
+ || phdr2[i].p_type == PT_TLS)
+ {
+ Elf64_External_Phdr tmp_phdr = *phdrp;
+ Elf64_External_Phdr tmp_phdr2 = *phdr2p;
+
+ memset (tmp_phdr.p_filesz, 0, 8);
+ memset (tmp_phdr.p_memsz, 0, 8);
+ memset (tmp_phdr.p_flags, 0, 4);
+ memset (tmp_phdr.p_align, 0, 8);
+ memset (tmp_phdr2.p_filesz, 0, 8);
+ memset (tmp_phdr2.p_memsz, 0, 8);
+ memset (tmp_phdr2.p_flags, 0, 4);
+ memset (tmp_phdr2.p_align, 0, 8);
+
+ if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr))
+ == 0)
+ continue;
+ }
+
+ /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
+ plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt");
+ if (plt2_asect)
+ {
+ int content2;
+ gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz;
+ CORE_ADDR filesz;
+
+ content2 = (bfd_section_flags (plt2_asect)
+ & SEC_HAS_CONTENTS) != 0;
+
+ filesz = extract_unsigned_integer (buf_filesz_p, 8,
+ byte_order);
+
+ /* PLT2_ASECT is from on-disk file (exec_bfd) while
+ FILESZ is from the in-memory image. */
+ if (content2)
+ filesz += bfd_section_size (plt2_asect);
+ else
+ filesz -= bfd_section_size (plt2_asect);
+
+ store_unsigned_integer (buf_filesz_p, 8, byte_order,
+ filesz);
+
+ if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
+ continue;
+ }
+
+ return 0;
+ }
+ }
+ else
+ return 0;
+ }
+ }
+
+ if (info_verbose)
+ {
+ /* It can be printed repeatedly as there is no easy way to check
+ the executable symbols/file has been already relocated to
+ displacement. */
+
+ printf_unfiltered (_("Using PIE (Position Independent Executable) "
+ "displacement %s for \"%s\".\n"),
+ paddress (target_gdbarch (), exec_displacement),
+ bfd_get_filename (exec_bfd));
+ }
+
+ *displacementp = exec_displacement;
+ return 1;
}
/* Relocate the main executable. This function should be called upon
- stopping the inferior process at the entry point to the program.
- The entry point from BFD is compared to the PC and if they are
- different, the main executable is relocated by the proper amount.
-
- As written it will only attempt to relocate executables which
- lack interpreter sections. It seems likely that only dynamic
- linker executables will get relocated, though it should work
- properly for a position-independent static executable as well. */
+ stopping the inferior process at the entry point to the program.
+ The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
+ different, the main executable is relocated by the proper amount. */
static void
svr4_relocate_main_executable (void)
{
- asection *interp_sect;
- CORE_ADDR pc = read_pc ();
-
- /* Decide if the objfile needs to be relocated. As indicated above,
- we will only be here when execution is stopped at the beginning
- of the program. Relocation is necessary if the address at which
- we are presently stopped differs from the start address stored in
- the executable AND there's no interpreter section. The condition
- regarding the interpreter section is very important because if
- there *is* an interpreter section, execution will begin there
- instead. When there is an interpreter section, the start address
- is (presumably) used by the interpreter at some point to start
- execution of the program.
-
- If there is an interpreter, it is normal for it to be set to an
- arbitrary address at the outset. The job of finding it is
- handled in enable_break().
-
- So, to summarize, relocations are necessary when there is no
- interpreter section and the start address obtained from the
- executable is different from the address at which GDB is
- currently stopped.
-
- [ The astute reader will note that we also test to make sure that
- the executable in question has the DYNAMIC flag set. It is my
- opinion that this test is unnecessary (undesirable even). It
- was added to avoid inadvertent relocation of an executable
- whose e_type member in the ELF header is not ET_DYN. There may
- be a time in the future when it is desirable to do relocations
- on other types of files as well in which case this condition
- should either be removed or modified to accomodate the new file
- type. (E.g, an ET_EXEC executable which has been built to be
- position-independent could safely be relocated by the OS if
- desired. It is true that this violates the ABI, but the ABI
- has been known to be bent from time to time.) - Kevin, Nov 2000. ]
- */
-
- interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
- if (interp_sect == NULL
- && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0
- && (exec_entry_point (exec_bfd, &exec_ops) != pc))
- {
- struct cleanup *old_chain;
- struct section_offsets *new_offsets;
- int i, changed;
- CORE_ADDR displacement;
-
- /* It is necessary to relocate the objfile. The amount to
- relocate by is simply the address at which we are stopped
- minus the starting address from the executable.
-
- We relocate all of the sections by the same amount. This
- behavior is mandated by recent editions of the System V ABI.
- According to the System V Application Binary Interface,
- Edition 4.1, page 5-5:
-
- ... Though the system chooses virtual addresses for
- individual processes, it maintains the segments' relative
- positions. Because position-independent code uses relative
- addressesing between segments, the difference between
- virtual addresses in memory must match the difference
- between virtual addresses in the file. The difference
- between the virtual address of any segment in memory and
- the corresponding virtual address in the file is thus a
- single constant value for any one executable or shared
- object in a given process. This difference is the base
- address. One use of the base address is to relocate the
- memory image of the program during dynamic linking.
-
- The same language also appears in Edition 4.0 of the System V
- ABI and is left unspecified in some of the earlier editions. */
-
- displacement = pc - exec_entry_point (exec_bfd, &exec_ops);
- changed = 0;
-
- new_offsets = xcalloc (symfile_objfile->num_sections,
- sizeof (struct section_offsets));
- old_chain = make_cleanup (xfree, new_offsets);
+ CORE_ADDR displacement;
- for (i = 0; i < symfile_objfile->num_sections; i++)
- {
- if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))
- changed = 1;
- new_offsets->offsets[i] = displacement;
- }
+ /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS
+ probably contains the offsets computed using the PIE displacement
+ from the previous run, which of course are irrelevant for this run.
+ So we need to determine the new PIE displacement and recompute the
+ section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS
+ already contains pre-computed offsets.
- if (changed)
- objfile_relocate (symfile_objfile, new_offsets);
+ If we cannot compute the PIE displacement, either:
- do_cleanups (old_chain);
- }
-}
+ - The executable is not PIE.
-/*
+ - SYMFILE_OBJFILE does not match the executable started in the target.
+ This can happen for main executable symbols loaded at the host while
+ `ld.so --ld-args main-executable' is loaded in the target.
- GLOBAL FUNCTION
+ Then we leave the section offsets untouched and use them as is for
+ this run. Either:
- svr4_solib_create_inferior_hook -- shared library startup support
+ - These section offsets were properly reset earlier, and thus
+ already contain the correct values. This can happen for instance
+ when reconnecting via the remote protocol to a target that supports
+ the `qOffsets' packet.
- SYNOPSIS
+ - The section offsets were not reset earlier, and the best we can
+ hope is that the old offsets are still applicable to the new run. */
- void svr4_solib_create_inferior_hook ()
+ if (! svr4_exec_displacement (&displacement))
+ return;
+
+ /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file
+ addresses. */
+
+ if (symfile_objfile)
+ {
+ struct section_offsets *new_offsets;
+ int i;
+
+ new_offsets = XALLOCAVEC (struct section_offsets,
+ symfile_objfile->num_sections);
+
+ for (i = 0; i < symfile_objfile->num_sections; i++)
+ new_offsets->offsets[i] = displacement;
- DESCRIPTION
+ objfile_relocate (symfile_objfile, new_offsets);
+ }
+ else if (exec_bfd)
+ {
+ asection *asect;
- When gdb starts up the inferior, it nurses it along (through the
- shell) until it is ready to execute it's first instruction. At this
- point, this function gets called via expansion of the macro
- SOLIB_CREATE_INFERIOR_HOOK.
+ for (asect = exec_bfd->sections; asect != NULL; asect = asect->next)
+ exec_set_section_address (bfd_get_filename (exec_bfd), asect->index,
+ bfd_section_vma (asect) + displacement);
+ }
+}
- For SunOS executables, this first instruction is typically the
- one at "_start", or a similar text label, regardless of whether
- the executable is statically or dynamically linked. The runtime
- startup code takes care of dynamically linking in any shared
- libraries, once gdb allows the inferior to continue.
+/* Implement the "create_inferior_hook" target_solib_ops method.
For SVR4 executables, this first instruction is either the first
instruction in the dynamic linker (for dynamically linked
shared libraries, maps in the actual user executable, and then
jumps to "start" in the user executable.
- For both SunOS shared libraries, and SVR4 shared libraries, we
- can arrange to cooperate with the dynamic linker to discover the
- names of shared libraries that are dynamically linked, and the
- base addresses to which they are linked.
+ We can arrange to cooperate with the dynamic linker to discover the
+ names of shared libraries that are dynamically linked, and the base
+ addresses to which they are linked.
This function is responsible for discovering those names and
addresses, and saving sufficient information about them to allow
- their symbols to be read at a later time.
+ their symbols to be read at a later time. */
- FIXME
+static void
+svr4_solib_create_inferior_hook (int from_tty)
+{
+ struct svr4_info *info;
- Between enable_break() and disable_break(), this code does not
- properly handle hitting breakpoints which the user might have
- set in the startup code or in the dynamic linker itself. Proper
- handling will probably have to wait until the implementation is
- changed to use the "breakpoint handler function" method.
+ info = get_svr4_info (current_program_space);
- Also, what if child has exit()ed? Must exit loop somehow.
- */
+ /* Clear the probes-based interface's state. */
+ free_probes_table (info);
+ free_solib_list (info);
-static void
-svr4_solib_create_inferior_hook (void)
-{
/* Relocate the main executable if necessary. */
svr4_relocate_main_executable ();
- if (!svr4_have_link_map_offsets ())
+ /* No point setting a breakpoint in the dynamic linker if we can't
+ hit it (e.g., a core file, or a trace file). */
+ if (!target_has_execution)
return;
- if (!enable_break ())
+ if (!svr4_have_link_map_offsets ())
return;
-#if defined(_SCO_DS)
- /* SCO needs the loop below, other systems should be using the
- special shared library breakpoints and the shared library breakpoint
- service routine.
-
- Now run the target. It will eventually hit the breakpoint, at
- which point all of the libraries will have been mapped in and we
- can go groveling around in the dynamic linker structures to find
- out what we need to know about them. */
-
- clear_proceed_status ();
- stop_soon = STOP_QUIETLY;
- stop_signal = TARGET_SIGNAL_0;
- do
- {
- target_resume (pid_to_ptid (-1), 0, stop_signal);
- wait_for_inferior (0);
- }
- while (stop_signal != TARGET_SIGNAL_TRAP);
- stop_soon = NO_STOP_QUIETLY;
-#endif /* defined(_SCO_DS) */
+ if (!enable_break (info, from_tty))
+ return;
}
static void
svr4_clear_solib (void)
{
- debug_base = 0;
- debug_loader_offset_p = 0;
- debug_loader_offset = 0;
- xfree (debug_loader_name);
- debug_loader_name = NULL;
- main_lm_addr = 0;
+ struct svr4_info *info;
+
+ info = get_svr4_info (current_program_space);
+ info->debug_base = 0;
+ info->debug_loader_offset_p = 0;
+ info->debug_loader_offset = 0;
+ xfree (info->debug_loader_name);
+ info->debug_loader_name = NULL;
}
-static void
-svr4_free_so (struct so_list *so)
-{
- xfree (so->lm_info->lm);
- xfree (so->lm_info);
-}
-
-
/* Clear any bits of ADDR that wouldn't fit in a target-format
data pointer. "Data pointer" here refers to whatever sort of
address the dynamic linker uses to manage its sections. At the
static CORE_ADDR
svr4_truncate_ptr (CORE_ADDR addr)
{
- if (gdbarch_ptr_bit (target_gdbarch) == sizeof (CORE_ADDR) * 8)
+ if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR) * 8)
/* We don't need to truncate anything, and the bit twiddling below
will fail due to overflow problems. */
return addr;
else
- return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch)) - 1);
+ return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1);
}
static void
svr4_relocate_section_addresses (struct so_list *so,
- struct section_table *sec)
+ struct target_section *sec)
{
- sec->addr = svr4_truncate_ptr (sec->addr + LM_ADDR_CHECK (so,
- sec->bfd));
- sec->endaddr = svr4_truncate_ptr (sec->endaddr + LM_ADDR_CHECK (so,
- sec->bfd));
+ bfd *abfd = sec->the_bfd_section->owner;
+
+ sec->addr = svr4_truncate_ptr (sec->addr + lm_addr_check (so, abfd));
+ sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so, abfd));
}
\f
set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch,
struct link_map_offsets *(*flmo) (void))
{
- struct solib_svr4_ops *ops = gdbarch_data (gdbarch, solib_svr4_data);
+ struct solib_svr4_ops *ops
+ = (struct solib_svr4_ops *) gdbarch_data (gdbarch, solib_svr4_data);
ops->fetch_link_map_offsets = flmo;
set_solib_ops (gdbarch, &svr4_so_ops);
+ set_gdbarch_iterate_over_objfiles_in_search_order
+ (gdbarch, svr4_iterate_over_objfiles_in_search_order);
}
/* Fetch a link_map_offsets structure using the architecture-specific
static struct link_map_offsets *
svr4_fetch_link_map_offsets (void)
{
- struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch, solib_svr4_data);
+ struct solib_svr4_ops *ops
+ = (struct solib_svr4_ops *) gdbarch_data (target_gdbarch (),
+ solib_svr4_data);
gdb_assert (ops->fetch_link_map_offsets);
return ops->fetch_link_map_offsets ();
static int
svr4_have_link_map_offsets (void)
{
- struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch, solib_svr4_data);
+ struct solib_svr4_ops *ops
+ = (struct solib_svr4_ops *) gdbarch_data (target_gdbarch (),
+ solib_svr4_data);
+
return (ops->fetch_link_map_offsets != NULL);
}
\f
/* Most OS'es that have SVR4-style ELF dynamic libraries define a
`struct r_debug' and a `struct link_map' that are binary compatible
- with the origional SVR4 implementation. */
+ with the original SVR4 implementation. */
/* Fetch (and possibly build) an appropriate `struct link_map_offsets'
for an ILP32 SVR4 system. */
-
+
struct link_map_offsets *
svr4_ilp32_fetch_link_map_offsets (void)
{
/* Fetch (and possibly build) an appropriate `struct link_map_offsets'
for an LP64 SVR4 system. */
-
+
struct link_map_offsets *
svr4_lp64_fetch_link_map_offsets (void)
{
struct target_so_ops svr4_so_ops;
-/* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
+/* Search order for ELF DSOs linked with -Bsymbolic. Those DSOs have a
different rule for symbol lookup. The lookup begins here in the DSO, not in
the main executable. */
-static struct symbol *
-elf_lookup_lib_symbol (const struct objfile *objfile,
- const char *name,
- const char *linkage_name,
- const domain_enum domain)
+static void
+svr4_iterate_over_objfiles_in_search_order
+ (struct gdbarch *gdbarch,
+ iterate_over_objfiles_in_search_order_cb_ftype *cb,
+ void *cb_data, struct objfile *current_objfile)
{
- if (objfile->obfd == NULL
- || scan_dyntag (DT_SYMBOLIC, objfile->obfd, NULL) != 1)
- return NULL;
+ bool checked_current_objfile = false;
+ if (current_objfile != nullptr)
+ {
+ bfd *abfd;
- return lookup_global_symbol_from_objfile
- (objfile, name, linkage_name, domain);
-}
+ if (current_objfile->separate_debug_objfile_backlink != nullptr)
+ current_objfile = current_objfile->separate_debug_objfile_backlink;
+
+ if (current_objfile == symfile_objfile)
+ abfd = exec_bfd;
+ else
+ abfd = current_objfile->obfd;
-extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */
+ if (abfd != nullptr
+ && scan_dyntag (DT_SYMBOLIC, abfd, nullptr, nullptr) == 1)
+ {
+ checked_current_objfile = true;
+ if (cb (current_objfile, cb_data) != 0)
+ return;
+ }
+ }
+
+ for (objfile *objfile : current_program_space->objfiles ())
+ {
+ if (checked_current_objfile && objfile == current_objfile)
+ continue;
+ if (cb (objfile, cb_data) != 0)
+ return;
+ }
+}
void
_initialize_svr4_solib (void)
svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses;
svr4_so_ops.free_so = svr4_free_so;
+ svr4_so_ops.clear_so = svr4_clear_so;
svr4_so_ops.clear_solib = svr4_clear_solib;
svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook;
- svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling;
svr4_so_ops.current_sos = svr4_current_sos;
svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code;
- svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol;
+ svr4_so_ops.bfd_open = solib_bfd_open;
svr4_so_ops.same = svr4_same;
+ svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core;
+ svr4_so_ops.update_breakpoints = svr4_update_solib_event_breakpoints;
+ svr4_so_ops.handle_event = svr4_handle_solib_event;
+
+ gdb::observers::free_objfile.attach (svr4_free_objfile_observer);
}
projects / deliverable / binutils-gdb.git / blobdiff