1 /* Handle SVR4 shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990-2019 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "elf/external.h"
23 #include "elf/common.h"
35 #include "gdbthread.h"
36 #include "observable.h"
40 #include "solib-svr4.h"
42 #include "bfd-target.h"
49 static struct link_map_offsets
*svr4_fetch_link_map_offsets (void);
50 static int svr4_have_link_map_offsets (void);
51 static void svr4_relocate_main_executable (void);
52 static void svr4_free_library_list (void *p_list
);
54 /* On SVR4 systems, a list of symbols in the dynamic linker where
55 GDB can try to place a breakpoint to monitor shared library
58 If none of these symbols are found, or other errors occur, then
59 SVR4 systems will fall back to using a symbol as the "startup
60 mapping complete" breakpoint address. */
62 static const char * const solib_break_names
[] =
68 "__dl_rtld_db_dlactivity",
74 static const char * const bkpt_names
[] =
82 static const char * const main_name_list
[] =
88 /* What to do when a probe stop occurs. */
92 /* Something went seriously wrong. Stop using probes and
93 revert to using the older interface. */
94 PROBES_INTERFACE_FAILED
,
96 /* No action is required. The shared object list is still
100 /* The shared object list should be reloaded entirely. */
103 /* Attempt to incrementally update the shared object list. If
104 the update fails or is not possible, fall back to reloading
109 /* A probe's name and its associated action. */
113 /* The name of the probe. */
116 /* What to do when a probe stop occurs. */
117 enum probe_action action
;
120 /* A list of named probes and their associated actions. If all
121 probes are present in the dynamic linker then the probes-based
122 interface will be used. */
124 static const struct probe_info probe_info
[] =
126 { "init_start", DO_NOTHING
},
127 { "init_complete", FULL_RELOAD
},
128 { "map_start", DO_NOTHING
},
129 { "map_failed", DO_NOTHING
},
130 { "reloc_complete", UPDATE_OR_RELOAD
},
131 { "unmap_start", DO_NOTHING
},
132 { "unmap_complete", FULL_RELOAD
},
135 #define NUM_PROBES ARRAY_SIZE (probe_info)
137 /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
138 the same shared library. */
141 svr4_same_1 (const char *gdb_so_name
, const char *inferior_so_name
)
143 if (strcmp (gdb_so_name
, inferior_so_name
) == 0)
146 /* On Solaris, when starting inferior we think that dynamic linker is
147 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
148 contains /lib/ld.so.1. Sometimes one file is a link to another, but
149 sometimes they have identical content, but are not linked to each
150 other. We don't restrict this check for Solaris, but the chances
151 of running into this situation elsewhere are very low. */
152 if (strcmp (gdb_so_name
, "/usr/lib/ld.so.1") == 0
153 && strcmp (inferior_so_name
, "/lib/ld.so.1") == 0)
156 /* Similarly, we observed the same issue with amd64 and sparcv9, but with
157 different locations. */
158 if (strcmp (gdb_so_name
, "/usr/lib/amd64/ld.so.1") == 0
159 && strcmp (inferior_so_name
, "/lib/amd64/ld.so.1") == 0)
162 if (strcmp (gdb_so_name
, "/usr/lib/sparcv9/ld.so.1") == 0
163 && strcmp (inferior_so_name
, "/lib/sparcv9/ld.so.1") == 0)
170 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
172 return (svr4_same_1 (gdb
->so_original_name
, inferior
->so_original_name
));
175 static std::unique_ptr
<lm_info_svr4
>
176 lm_info_read (CORE_ADDR lm_addr
)
178 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
179 std::unique_ptr
<lm_info_svr4
> lm_info
;
181 gdb::byte_vector
lm (lmo
->link_map_size
);
183 if (target_read_memory (lm_addr
, lm
.data (), lmo
->link_map_size
) != 0)
184 warning (_("Error reading shared library list entry at %s"),
185 paddress (target_gdbarch (), lm_addr
));
188 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
190 lm_info
.reset (new lm_info_svr4
);
191 lm_info
->lm_addr
= lm_addr
;
193 lm_info
->l_addr_inferior
= extract_typed_address (&lm
[lmo
->l_addr_offset
],
195 lm_info
->l_ld
= extract_typed_address (&lm
[lmo
->l_ld_offset
], ptr_type
);
196 lm_info
->l_next
= extract_typed_address (&lm
[lmo
->l_next_offset
],
198 lm_info
->l_prev
= extract_typed_address (&lm
[lmo
->l_prev_offset
],
200 lm_info
->l_name
= extract_typed_address (&lm
[lmo
->l_name_offset
],
208 has_lm_dynamic_from_link_map (void)
210 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
212 return lmo
->l_ld_offset
>= 0;
216 lm_addr_check (const struct so_list
*so
, bfd
*abfd
)
218 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
222 struct bfd_section
*dyninfo_sect
;
223 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
;
225 l_addr
= li
->l_addr_inferior
;
227 if (! abfd
|| ! has_lm_dynamic_from_link_map ())
230 l_dynaddr
= li
->l_ld
;
232 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
233 if (dyninfo_sect
== NULL
)
236 dynaddr
= bfd_section_vma (abfd
, dyninfo_sect
);
238 if (dynaddr
+ l_addr
!= l_dynaddr
)
240 CORE_ADDR align
= 0x1000;
241 CORE_ADDR minpagesize
= align
;
243 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
245 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
246 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
251 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
252 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
253 align
= phdr
[i
].p_align
;
255 minpagesize
= get_elf_backend_data (abfd
)->minpagesize
;
258 /* Turn it into a mask. */
261 /* If the changes match the alignment requirements, we
262 assume we're using a core file that was generated by the
263 same binary, just prelinked with a different base offset.
264 If it doesn't match, we may have a different binary, the
265 same binary with the dynamic table loaded at an unrelated
266 location, or anything, really. To avoid regressions,
267 don't adjust the base offset in the latter case, although
268 odds are that, if things really changed, debugging won't
271 One could expect more the condition
272 ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
273 but the one below is relaxed for PPC. The PPC kernel supports
274 either 4k or 64k page sizes. To be prepared for 64k pages,
275 PPC ELF files are built using an alignment requirement of 64k.
276 However, when running on a kernel supporting 4k pages, the memory
277 mapping of the library may not actually happen on a 64k boundary!
279 (In the usual case where (l_addr & align) == 0, this check is
280 equivalent to the possibly expected check above.)
282 Even on PPC it must be zero-aligned at least for MINPAGESIZE. */
284 l_addr
= l_dynaddr
- dynaddr
;
286 if ((l_addr
& (minpagesize
- 1)) == 0
287 && (l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
290 printf_unfiltered (_("Using PIC (Position Independent Code) "
291 "prelink displacement %s for \"%s\".\n"),
292 paddress (target_gdbarch (), l_addr
),
297 /* There is no way to verify the library file matches. prelink
298 can during prelinking of an unprelinked file (or unprelinking
299 of a prelinked file) shift the DYNAMIC segment by arbitrary
300 offset without any page size alignment. There is no way to
301 find out the ELF header and/or Program Headers for a limited
302 verification if it they match. One could do a verification
303 of the DYNAMIC segment. Still the found address is the best
304 one GDB could find. */
306 warning (_(".dynamic section for \"%s\" "
307 "is not at the expected address "
308 "(wrong library or version mismatch?)"), so
->so_name
);
320 /* Per pspace SVR4 specific data. */
324 CORE_ADDR debug_base
; /* Base of dynamic linker structures. */
326 /* Validity flag for debug_loader_offset. */
327 int debug_loader_offset_p
;
329 /* Load address for the dynamic linker, inferred. */
330 CORE_ADDR debug_loader_offset
;
332 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
333 char *debug_loader_name
;
335 /* Load map address for the main executable. */
336 CORE_ADDR main_lm_addr
;
338 CORE_ADDR interp_text_sect_low
;
339 CORE_ADDR interp_text_sect_high
;
340 CORE_ADDR interp_plt_sect_low
;
341 CORE_ADDR interp_plt_sect_high
;
343 /* Nonzero if the list of objects was last obtained from the target
344 via qXfer:libraries-svr4:read. */
347 /* Table of struct probe_and_action instances, used by the
348 probes-based interface to map breakpoint addresses to probes
349 and their associated actions. Lookup is performed using
350 probe_and_action->prob->address. */
353 /* List of objects loaded into the inferior, used by the probes-
355 struct so_list
*solib_list
;
358 /* Per-program-space data key. */
359 static const struct program_space_data
*solib_svr4_pspace_data
;
361 /* Free the probes table. */
364 free_probes_table (struct svr4_info
*info
)
366 if (info
->probes_table
== NULL
)
369 htab_delete (info
->probes_table
);
370 info
->probes_table
= NULL
;
373 /* Free the solib list. */
376 free_solib_list (struct svr4_info
*info
)
378 svr4_free_library_list (&info
->solib_list
);
379 info
->solib_list
= NULL
;
383 svr4_pspace_data_cleanup (struct program_space
*pspace
, void *arg
)
385 struct svr4_info
*info
= (struct svr4_info
*) arg
;
387 free_probes_table (info
);
388 free_solib_list (info
);
393 /* Get the current svr4 data. If none is found yet, add it now. This
394 function always returns a valid object. */
396 static struct svr4_info
*
399 struct svr4_info
*info
;
401 info
= (struct svr4_info
*) program_space_data (current_program_space
,
402 solib_svr4_pspace_data
);
406 info
= XCNEW (struct svr4_info
);
407 set_program_space_data (current_program_space
, solib_svr4_pspace_data
, info
);
411 /* Local function prototypes */
413 static int match_main (const char *);
415 /* Read program header TYPE from inferior memory. The header is found
416 by scanning the OS auxiliary vector.
418 If TYPE == -1, return the program headers instead of the contents of
421 Return vector of bytes holding the program header contents, or an empty
422 optional on failure. If successful and P_ARCH_SIZE is non-NULL, the target
423 architecture size (32-bit or 64-bit) is returned to *P_ARCH_SIZE. Likewise,
424 the base address of the section is returned in *BASE_ADDR. */
426 static gdb::optional
<gdb::byte_vector
>
427 read_program_header (int type
, int *p_arch_size
, CORE_ADDR
*base_addr
)
429 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
430 CORE_ADDR at_phdr
, at_phent
, at_phnum
, pt_phdr
= 0;
431 int arch_size
, sect_size
;
435 /* Get required auxv elements from target. */
436 if (target_auxv_search (current_top_target (), AT_PHDR
, &at_phdr
) <= 0)
438 if (target_auxv_search (current_top_target (), AT_PHENT
, &at_phent
) <= 0)
440 if (target_auxv_search (current_top_target (), AT_PHNUM
, &at_phnum
) <= 0)
442 if (!at_phdr
|| !at_phnum
)
445 /* Determine ELF architecture type. */
446 if (at_phent
== sizeof (Elf32_External_Phdr
))
448 else if (at_phent
== sizeof (Elf64_External_Phdr
))
453 /* Find the requested segment. */
457 sect_size
= at_phent
* at_phnum
;
459 else if (arch_size
== 32)
461 Elf32_External_Phdr phdr
;
464 /* Search for requested PHDR. */
465 for (i
= 0; i
< at_phnum
; i
++)
469 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
470 (gdb_byte
*)&phdr
, sizeof (phdr
)))
473 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
476 if (p_type
== PT_PHDR
)
479 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
490 /* Retrieve address and size. */
491 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
493 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
498 Elf64_External_Phdr phdr
;
501 /* Search for requested PHDR. */
502 for (i
= 0; i
< at_phnum
; i
++)
506 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
507 (gdb_byte
*)&phdr
, sizeof (phdr
)))
510 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
513 if (p_type
== PT_PHDR
)
516 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
527 /* Retrieve address and size. */
528 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
530 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
534 /* PT_PHDR is optional, but we really need it
535 for PIE to make this work in general. */
539 /* at_phdr is real address in memory. pt_phdr is what pheader says it is.
540 Relocation offset is the difference between the two. */
541 sect_addr
= sect_addr
+ (at_phdr
- pt_phdr
);
544 /* Read in requested program header. */
545 gdb::byte_vector
buf (sect_size
);
546 if (target_read_memory (sect_addr
, buf
.data (), sect_size
))
550 *p_arch_size
= arch_size
;
552 *base_addr
= sect_addr
;
558 /* Return program interpreter string. */
559 static gdb::optional
<gdb::byte_vector
>
560 find_program_interpreter (void)
562 /* If we have an exec_bfd, use its section table. */
564 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
566 struct bfd_section
*interp_sect
;
568 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
569 if (interp_sect
!= NULL
)
571 int sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
573 gdb::byte_vector
buf (sect_size
);
574 bfd_get_section_contents (exec_bfd
, interp_sect
, buf
.data (), 0,
580 /* If we didn't find it, use the target auxiliary vector. */
581 return read_program_header (PT_INTERP
, NULL
, NULL
);
585 /* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is
586 found, 1 is returned and the corresponding PTR is set. */
589 scan_dyntag (const int desired_dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
,
592 int arch_size
, step
, sect_size
;
594 CORE_ADDR dyn_ptr
, dyn_addr
;
595 gdb_byte
*bufend
, *bufstart
, *buf
;
596 Elf32_External_Dyn
*x_dynp_32
;
597 Elf64_External_Dyn
*x_dynp_64
;
598 struct bfd_section
*sect
;
599 struct target_section
*target_section
;
604 if (bfd_get_flavour (abfd
) != bfd_target_elf_flavour
)
607 arch_size
= bfd_get_arch_size (abfd
);
611 /* Find the start address of the .dynamic section. */
612 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
616 for (target_section
= current_target_sections
->sections
;
617 target_section
< current_target_sections
->sections_end
;
619 if (sect
== target_section
->the_bfd_section
)
621 if (target_section
< current_target_sections
->sections_end
)
622 dyn_addr
= target_section
->addr
;
625 /* ABFD may come from OBJFILE acting only as a symbol file without being
626 loaded into the target (see add_symbol_file_command). This case is
627 such fallback to the file VMA address without the possibility of
628 having the section relocated to its actual in-memory address. */
630 dyn_addr
= bfd_section_vma (abfd
, sect
);
633 /* Read in .dynamic from the BFD. We will get the actual value
634 from memory later. */
635 sect_size
= bfd_section_size (abfd
, sect
);
636 buf
= bufstart
= (gdb_byte
*) alloca (sect_size
);
637 if (!bfd_get_section_contents (abfd
, sect
,
641 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
642 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
643 : sizeof (Elf64_External_Dyn
);
644 for (bufend
= buf
+ sect_size
;
650 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
651 current_dyntag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
652 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
656 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
657 current_dyntag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
658 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
660 if (current_dyntag
== DT_NULL
)
662 if (current_dyntag
== desired_dyntag
)
664 /* If requested, try to read the runtime value of this .dynamic
668 struct type
*ptr_type
;
670 CORE_ADDR ptr_addr_1
;
672 ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
673 ptr_addr_1
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
674 if (target_read_memory (ptr_addr_1
, ptr_buf
, arch_size
/ 8) == 0)
675 dyn_ptr
= extract_typed_address (ptr_buf
, ptr_type
);
678 *ptr_addr
= dyn_addr
+ (buf
- bufstart
);
687 /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable,
688 found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1
689 is returned and the corresponding PTR is set. */
692 scan_dyntag_auxv (const int desired_dyntag
, CORE_ADDR
*ptr
,
695 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
701 /* Read in .dynamic section. */
702 gdb::optional
<gdb::byte_vector
> ph_data
703 = read_program_header (PT_DYNAMIC
, &arch_size
, &base_addr
);
707 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
708 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
709 : sizeof (Elf64_External_Dyn
);
710 for (gdb_byte
*buf
= ph_data
->data (), *bufend
= buf
+ ph_data
->size ();
711 buf
< bufend
; buf
+= step
)
715 Elf32_External_Dyn
*dynp
= (Elf32_External_Dyn
*) buf
;
717 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
719 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
724 Elf64_External_Dyn
*dynp
= (Elf64_External_Dyn
*) buf
;
726 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
728 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
731 if (current_dyntag
== DT_NULL
)
734 if (current_dyntag
== desired_dyntag
)
740 *ptr_addr
= base_addr
+ buf
- ph_data
->data ();
749 /* Locate the base address of dynamic linker structs for SVR4 elf
752 For SVR4 elf targets the address of the dynamic linker's runtime
753 structure is contained within the dynamic info section in the
754 executable file. The dynamic section is also mapped into the
755 inferior address space. Because the runtime loader fills in the
756 real address before starting the inferior, we have to read in the
757 dynamic info section from the inferior address space.
758 If there are any errors while trying to find the address, we
759 silently return 0, otherwise the found address is returned. */
762 elf_locate_base (void)
764 struct bound_minimal_symbol msymbol
;
765 CORE_ADDR dyn_ptr
, dyn_ptr_addr
;
767 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
768 instead of DT_DEBUG, although they sometimes contain an unused
770 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
, NULL
)
771 || scan_dyntag_auxv (DT_MIPS_RLD_MAP
, &dyn_ptr
, NULL
))
773 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
775 int pbuf_size
= TYPE_LENGTH (ptr_type
);
777 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
778 /* DT_MIPS_RLD_MAP contains a pointer to the address
779 of the dynamic link structure. */
780 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
782 return extract_typed_address (pbuf
, ptr_type
);
785 /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form
786 because of needing to support PIE. DT_MIPS_RLD_MAP will also exist
788 if (scan_dyntag (DT_MIPS_RLD_MAP_REL
, exec_bfd
, &dyn_ptr
, &dyn_ptr_addr
)
789 || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL
, &dyn_ptr
, &dyn_ptr_addr
))
791 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
793 int pbuf_size
= TYPE_LENGTH (ptr_type
);
795 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
796 /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the
797 DT slot to the address of the dynamic link structure. */
798 if (target_read_memory (dyn_ptr
+ dyn_ptr_addr
, pbuf
, pbuf_size
))
800 return extract_typed_address (pbuf
, ptr_type
);
804 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
, NULL
)
805 || scan_dyntag_auxv (DT_DEBUG
, &dyn_ptr
, NULL
))
808 /* This may be a static executable. Look for the symbol
809 conventionally named _r_debug, as a last resort. */
810 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
811 if (msymbol
.minsym
!= NULL
)
812 return BMSYMBOL_VALUE_ADDRESS (msymbol
);
814 /* DT_DEBUG entry not found. */
818 /* Locate the base address of dynamic linker structs.
820 For both the SunOS and SVR4 shared library implementations, if the
821 inferior executable has been linked dynamically, there is a single
822 address somewhere in the inferior's data space which is the key to
823 locating all of the dynamic linker's runtime structures. This
824 address is the value of the debug base symbol. The job of this
825 function is to find and return that address, or to return 0 if there
826 is no such address (the executable is statically linked for example).
828 For SunOS, the job is almost trivial, since the dynamic linker and
829 all of it's structures are statically linked to the executable at
830 link time. Thus the symbol for the address we are looking for has
831 already been added to the minimal symbol table for the executable's
832 objfile at the time the symbol file's symbols were read, and all we
833 have to do is look it up there. Note that we explicitly do NOT want
834 to find the copies in the shared library.
836 The SVR4 version is a bit more complicated because the address
837 is contained somewhere in the dynamic info section. We have to go
838 to a lot more work to discover the address of the debug base symbol.
839 Because of this complexity, we cache the value we find and return that
840 value on subsequent invocations. Note there is no copy in the
841 executable symbol tables. */
844 locate_base (struct svr4_info
*info
)
846 /* Check to see if we have a currently valid address, and if so, avoid
847 doing all this work again and just return the cached address. If
848 we have no cached address, try to locate it in the dynamic info
849 section for ELF executables. There's no point in doing any of this
850 though if we don't have some link map offsets to work with. */
852 if (info
->debug_base
== 0 && svr4_have_link_map_offsets ())
853 info
->debug_base
= elf_locate_base ();
854 return info
->debug_base
;
857 /* Find the first element in the inferior's dynamic link map, and
858 return its address in the inferior. Return zero if the address
859 could not be determined.
861 FIXME: Perhaps we should validate the info somehow, perhaps by
862 checking r_version for a known version number, or r_state for
866 solib_svr4_r_map (struct svr4_info
*info
)
868 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
869 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
874 addr
= read_memory_typed_address (info
->debug_base
+ lmo
->r_map_offset
,
877 CATCH (ex
, RETURN_MASK_ERROR
)
879 exception_print (gdb_stderr
, ex
);
886 /* Find r_brk from the inferior's debug base. */
889 solib_svr4_r_brk (struct svr4_info
*info
)
891 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
892 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
894 return read_memory_typed_address (info
->debug_base
+ lmo
->r_brk_offset
,
898 /* Find the link map for the dynamic linker (if it is not in the
899 normal list of loaded shared objects). */
902 solib_svr4_r_ldsomap (struct svr4_info
*info
)
904 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
905 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
906 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
907 ULONGEST version
= 0;
911 /* Check version, and return zero if `struct r_debug' doesn't have
912 the r_ldsomap member. */
914 = read_memory_unsigned_integer (info
->debug_base
+ lmo
->r_version_offset
,
915 lmo
->r_version_size
, byte_order
);
917 CATCH (ex
, RETURN_MASK_ERROR
)
919 exception_print (gdb_stderr
, ex
);
923 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
926 return read_memory_typed_address (info
->debug_base
+ lmo
->r_ldsomap_offset
,
930 /* On Solaris systems with some versions of the dynamic linker,
931 ld.so's l_name pointer points to the SONAME in the string table
932 rather than into writable memory. So that GDB can find shared
933 libraries when loading a core file generated by gcore, ensure that
934 memory areas containing the l_name string are saved in the core
938 svr4_keep_data_in_core (CORE_ADDR vaddr
, unsigned long size
)
940 struct svr4_info
*info
;
944 info
= get_svr4_info ();
946 info
->debug_base
= 0;
948 if (!info
->debug_base
)
951 ldsomap
= solib_svr4_r_ldsomap (info
);
955 std::unique_ptr
<lm_info_svr4
> li
= lm_info_read (ldsomap
);
956 name_lm
= li
!= NULL
? li
->l_name
: 0;
958 return (name_lm
>= vaddr
&& name_lm
< vaddr
+ size
);
964 open_symbol_file_object (int from_tty
)
966 CORE_ADDR lm
, l_name
;
967 gdb::unique_xmalloc_ptr
<char> filename
;
969 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
970 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
971 int l_name_size
= TYPE_LENGTH (ptr_type
);
972 gdb::byte_vector
l_name_buf (l_name_size
);
973 struct svr4_info
*info
= get_svr4_info ();
974 symfile_add_flags add_flags
= 0;
977 add_flags
|= SYMFILE_VERBOSE
;
980 if (!query (_("Attempt to reload symbols from process? ")))
983 /* Always locate the debug struct, in case it has moved. */
984 info
->debug_base
= 0;
985 if (locate_base (info
) == 0)
986 return 0; /* failed somehow... */
988 /* First link map member should be the executable. */
989 lm
= solib_svr4_r_map (info
);
991 return 0; /* failed somehow... */
993 /* Read address of name from target memory to GDB. */
994 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
.data (), l_name_size
);
996 /* Convert the address to host format. */
997 l_name
= extract_typed_address (l_name_buf
.data (), ptr_type
);
1000 return 0; /* No filename. */
1002 /* Now fetch the filename from target memory. */
1003 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
1007 warning (_("failed to read exec filename from attached file: %s"),
1008 safe_strerror (errcode
));
1012 /* Have a pathname: read the symbol file. */
1013 symbol_file_add_main (filename
.get (), add_flags
);
1018 /* Data exchange structure for the XML parser as returned by
1019 svr4_current_sos_via_xfer_libraries. */
1021 struct svr4_library_list
1023 struct so_list
*head
, **tailp
;
1025 /* Inferior address of struct link_map used for the main executable. It is
1026 NULL if not known. */
1030 /* Implementation for target_so_ops.free_so. */
1033 svr4_free_so (struct so_list
*so
)
1035 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1040 /* Implement target_so_ops.clear_so. */
1043 svr4_clear_so (struct so_list
*so
)
1045 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1051 /* Free so_list built so far (called via cleanup). */
1054 svr4_free_library_list (void *p_list
)
1056 struct so_list
*list
= *(struct so_list
**) p_list
;
1058 while (list
!= NULL
)
1060 struct so_list
*next
= list
->next
;
1067 /* Copy library list. */
1069 static struct so_list
*
1070 svr4_copy_library_list (struct so_list
*src
)
1072 struct so_list
*dst
= NULL
;
1073 struct so_list
**link
= &dst
;
1077 struct so_list
*newobj
;
1079 newobj
= XNEW (struct so_list
);
1080 memcpy (newobj
, src
, sizeof (struct so_list
));
1082 lm_info_svr4
*src_li
= (lm_info_svr4
*) src
->lm_info
;
1083 newobj
->lm_info
= new lm_info_svr4 (*src_li
);
1085 newobj
->next
= NULL
;
1087 link
= &newobj
->next
;
1095 #ifdef HAVE_LIBEXPAT
1097 #include "xml-support.h"
1099 /* Handle the start of a <library> element. Note: new elements are added
1100 at the tail of the list, keeping the list in order. */
1103 library_list_start_library (struct gdb_xml_parser
*parser
,
1104 const struct gdb_xml_element
*element
,
1106 std::vector
<gdb_xml_value
> &attributes
)
1108 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1110 = (const char *) xml_find_attribute (attributes
, "name")->value
.get ();
1112 = (ULONGEST
*) xml_find_attribute (attributes
, "lm")->value
.get ();
1114 = (ULONGEST
*) xml_find_attribute (attributes
, "l_addr")->value
.get ();
1116 = (ULONGEST
*) xml_find_attribute (attributes
, "l_ld")->value
.get ();
1117 struct so_list
*new_elem
;
1119 new_elem
= XCNEW (struct so_list
);
1120 lm_info_svr4
*li
= new lm_info_svr4
;
1121 new_elem
->lm_info
= li
;
1123 li
->l_addr_inferior
= *l_addrp
;
1126 strncpy (new_elem
->so_name
, name
, sizeof (new_elem
->so_name
) - 1);
1127 new_elem
->so_name
[sizeof (new_elem
->so_name
) - 1] = 0;
1128 strcpy (new_elem
->so_original_name
, new_elem
->so_name
);
1130 *list
->tailp
= new_elem
;
1131 list
->tailp
= &new_elem
->next
;
1134 /* Handle the start of a <library-list-svr4> element. */
1137 svr4_library_list_start_list (struct gdb_xml_parser
*parser
,
1138 const struct gdb_xml_element
*element
,
1140 std::vector
<gdb_xml_value
> &attributes
)
1142 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1144 = (const char *) xml_find_attribute (attributes
, "version")->value
.get ();
1145 struct gdb_xml_value
*main_lm
= xml_find_attribute (attributes
, "main-lm");
1147 if (strcmp (version
, "1.0") != 0)
1148 gdb_xml_error (parser
,
1149 _("SVR4 Library list has unsupported version \"%s\""),
1153 list
->main_lm
= *(ULONGEST
*) main_lm
->value
.get ();
1156 /* The allowed elements and attributes for an XML library list.
1157 The root element is a <library-list>. */
1159 static const struct gdb_xml_attribute svr4_library_attributes
[] =
1161 { "name", GDB_XML_AF_NONE
, NULL
, NULL
},
1162 { "lm", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1163 { "l_addr", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1164 { "l_ld", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1165 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1168 static const struct gdb_xml_element svr4_library_list_children
[] =
1171 "library", svr4_library_attributes
, NULL
,
1172 GDB_XML_EF_REPEATABLE
| GDB_XML_EF_OPTIONAL
,
1173 library_list_start_library
, NULL
1175 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1178 static const struct gdb_xml_attribute svr4_library_list_attributes
[] =
1180 { "version", GDB_XML_AF_NONE
, NULL
, NULL
},
1181 { "main-lm", GDB_XML_AF_OPTIONAL
, gdb_xml_parse_attr_ulongest
, NULL
},
1182 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1185 static const struct gdb_xml_element svr4_library_list_elements
[] =
1187 { "library-list-svr4", svr4_library_list_attributes
, svr4_library_list_children
,
1188 GDB_XML_EF_NONE
, svr4_library_list_start_list
, NULL
},
1189 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1192 /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if
1194 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1195 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1196 empty, caller is responsible for freeing all its entries. */
1199 svr4_parse_libraries (const char *document
, struct svr4_library_list
*list
)
1201 auto cleanup
= make_scope_exit ([&] ()
1203 svr4_free_library_list (&list
->head
);
1206 memset (list
, 0, sizeof (*list
));
1207 list
->tailp
= &list
->head
;
1208 if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd",
1209 svr4_library_list_elements
, document
, list
) == 0)
1211 /* Parsed successfully, keep the result. */
1219 /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet.
1221 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1222 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1223 empty, caller is responsible for freeing all its entries.
1225 Note that ANNEX must be NULL if the remote does not explicitly allow
1226 qXfer:libraries-svr4:read packets with non-empty annexes. Support for
1227 this can be checked using target_augmented_libraries_svr4_read (). */
1230 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1233 gdb_assert (annex
== NULL
|| target_augmented_libraries_svr4_read ());
1235 /* Fetch the list of shared libraries. */
1236 gdb::optional
<gdb::char_vector
> svr4_library_document
1237 = target_read_stralloc (current_top_target (), TARGET_OBJECT_LIBRARIES_SVR4
,
1239 if (!svr4_library_document
)
1242 return svr4_parse_libraries (svr4_library_document
->data (), list
);
1248 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1256 /* If no shared library information is available from the dynamic
1257 linker, build a fallback list from other sources. */
1259 static struct so_list
*
1260 svr4_default_sos (void)
1262 struct svr4_info
*info
= get_svr4_info ();
1263 struct so_list
*newobj
;
1265 if (!info
->debug_loader_offset_p
)
1268 newobj
= XCNEW (struct so_list
);
1269 lm_info_svr4
*li
= new lm_info_svr4
;
1270 newobj
->lm_info
= li
;
1272 /* Nothing will ever check the other fields if we set l_addr_p. */
1273 li
->l_addr
= info
->debug_loader_offset
;
1276 strncpy (newobj
->so_name
, info
->debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
1277 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1278 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1283 /* Read the whole inferior libraries chain starting at address LM.
1284 Expect the first entry in the chain's previous entry to be PREV_LM.
1285 Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the
1286 first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according
1287 to it. Returns nonzero upon success. If zero is returned the
1288 entries stored to LINK_PTR_PTR are still valid although they may
1289 represent only part of the inferior library list. */
1292 svr4_read_so_list (CORE_ADDR lm
, CORE_ADDR prev_lm
,
1293 struct so_list
***link_ptr_ptr
, int ignore_first
)
1295 CORE_ADDR first_l_name
= 0;
1298 for (; lm
!= 0; prev_lm
= lm
, lm
= next_lm
)
1301 gdb::unique_xmalloc_ptr
<char> buffer
;
1303 so_list_up
newobj (XCNEW (struct so_list
));
1305 lm_info_svr4
*li
= lm_info_read (lm
).release ();
1306 newobj
->lm_info
= li
;
1310 next_lm
= li
->l_next
;
1312 if (li
->l_prev
!= prev_lm
)
1314 warning (_("Corrupted shared library list: %s != %s"),
1315 paddress (target_gdbarch (), prev_lm
),
1316 paddress (target_gdbarch (), li
->l_prev
));
1320 /* For SVR4 versions, the first entry in the link map is for the
1321 inferior executable, so we must ignore it. For some versions of
1322 SVR4, it has no name. For others (Solaris 2.3 for example), it
1323 does have a name, so we can no longer use a missing name to
1324 decide when to ignore it. */
1325 if (ignore_first
&& li
->l_prev
== 0)
1327 struct svr4_info
*info
= get_svr4_info ();
1329 first_l_name
= li
->l_name
;
1330 info
->main_lm_addr
= li
->lm_addr
;
1334 /* Extract this shared object's name. */
1335 target_read_string (li
->l_name
, &buffer
, SO_NAME_MAX_PATH_SIZE
- 1,
1339 /* If this entry's l_name address matches that of the
1340 inferior executable, then this is not a normal shared
1341 object, but (most likely) a vDSO. In this case, silently
1342 skip it; otherwise emit a warning. */
1343 if (first_l_name
== 0 || li
->l_name
!= first_l_name
)
1344 warning (_("Can't read pathname for load map: %s."),
1345 safe_strerror (errcode
));
1349 strncpy (newobj
->so_name
, buffer
.get (), SO_NAME_MAX_PATH_SIZE
- 1);
1350 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1351 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1353 /* If this entry has no name, or its name matches the name
1354 for the main executable, don't include it in the list. */
1355 if (! newobj
->so_name
[0] || match_main (newobj
->so_name
))
1359 /* Don't free it now. */
1360 **link_ptr_ptr
= newobj
.release ();
1361 *link_ptr_ptr
= &(**link_ptr_ptr
)->next
;
1367 /* Read the full list of currently loaded shared objects directly
1368 from the inferior, without referring to any libraries read and
1369 stored by the probes interface. Handle special cases relating
1370 to the first elements of the list. */
1372 static struct so_list
*
1373 svr4_current_sos_direct (struct svr4_info
*info
)
1376 struct so_list
*head
= NULL
;
1377 struct so_list
**link_ptr
= &head
;
1379 struct svr4_library_list library_list
;
1381 /* Fall back to manual examination of the target if the packet is not
1382 supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp
1383 tests a case where gdbserver cannot find the shared libraries list while
1384 GDB itself is able to find it via SYMFILE_OBJFILE.
1386 Unfortunately statically linked inferiors will also fall back through this
1387 suboptimal code path. */
1389 info
->using_xfer
= svr4_current_sos_via_xfer_libraries (&library_list
,
1391 if (info
->using_xfer
)
1393 if (library_list
.main_lm
)
1394 info
->main_lm_addr
= library_list
.main_lm
;
1396 return library_list
.head
? library_list
.head
: svr4_default_sos ();
1399 /* Always locate the debug struct, in case it has moved. */
1400 info
->debug_base
= 0;
1403 /* If we can't find the dynamic linker's base structure, this
1404 must not be a dynamically linked executable. Hmm. */
1405 if (! info
->debug_base
)
1406 return svr4_default_sos ();
1408 /* Assume that everything is a library if the dynamic loader was loaded
1409 late by a static executable. */
1410 if (exec_bfd
&& bfd_get_section_by_name (exec_bfd
, ".dynamic") == NULL
)
1415 auto cleanup
= make_scope_exit ([&] ()
1417 svr4_free_library_list (&head
);
1420 /* Walk the inferior's link map list, and build our list of
1421 `struct so_list' nodes. */
1422 lm
= solib_svr4_r_map (info
);
1424 svr4_read_so_list (lm
, 0, &link_ptr
, ignore_first
);
1426 /* On Solaris, the dynamic linker is not in the normal list of
1427 shared objects, so make sure we pick it up too. Having
1428 symbol information for the dynamic linker is quite crucial
1429 for skipping dynamic linker resolver code. */
1430 lm
= solib_svr4_r_ldsomap (info
);
1432 svr4_read_so_list (lm
, 0, &link_ptr
, 0);
1437 return svr4_default_sos ();
1442 /* Implement the main part of the "current_sos" target_so_ops
1445 static struct so_list
*
1446 svr4_current_sos_1 (void)
1448 struct svr4_info
*info
= get_svr4_info ();
1450 /* If the solib list has been read and stored by the probes
1451 interface then we return a copy of the stored list. */
1452 if (info
->solib_list
!= NULL
)
1453 return svr4_copy_library_list (info
->solib_list
);
1455 /* Otherwise obtain the solib list directly from the inferior. */
1456 return svr4_current_sos_direct (info
);
1459 /* Implement the "current_sos" target_so_ops method. */
1461 static struct so_list
*
1462 svr4_current_sos (void)
1464 struct so_list
*so_head
= svr4_current_sos_1 ();
1465 struct mem_range vsyscall_range
;
1467 /* Filter out the vDSO module, if present. Its symbol file would
1468 not be found on disk. The vDSO/vsyscall's OBJFILE is instead
1469 managed by symfile-mem.c:add_vsyscall_page. */
1470 if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range
)
1471 && vsyscall_range
.length
!= 0)
1473 struct so_list
**sop
;
1476 while (*sop
!= NULL
)
1478 struct so_list
*so
= *sop
;
1480 /* We can't simply match the vDSO by starting address alone,
1481 because lm_info->l_addr_inferior (and also l_addr) do not
1482 necessarily represent the real starting address of the
1483 ELF if the vDSO's ELF itself is "prelinked". The l_ld
1484 field (the ".dynamic" section of the shared object)
1485 always points at the absolute/resolved address though.
1486 So check whether that address is inside the vDSO's
1489 E.g., on Linux 3.16 (x86_64) the vDSO is a regular
1490 0-based ELF, and we see:
1493 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000
1494 (gdb) p/x *_r_debug.r_map.l_next
1495 $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...}
1497 And on Linux 2.6.32 (x86_64) we see:
1500 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000
1501 (gdb) p/x *_r_debug.r_map.l_next
1502 $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... }
1504 Dumping that vDSO shows:
1506 (gdb) info proc mappings
1507 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso]
1508 (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000
1509 # readelf -Wa vdso.bin
1511 Entry point address: 0xffffffffff700700
1514 [Nr] Name Type Address Off Size
1515 [ 0] NULL 0000000000000000 000000 000000
1516 [ 1] .hash HASH ffffffffff700120 000120 000038
1517 [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8
1519 [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0
1522 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1524 if (address_in_mem_range (li
->l_ld
, &vsyscall_range
))
1538 /* Get the address of the link_map for a given OBJFILE. */
1541 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
1544 struct svr4_info
*info
= get_svr4_info ();
1546 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1547 if (info
->main_lm_addr
== 0)
1548 solib_add (NULL
, 0, auto_solib_add
);
1550 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1551 if (objfile
== symfile_objfile
)
1552 return info
->main_lm_addr
;
1554 /* The other link map addresses may be found by examining the list
1555 of shared libraries. */
1556 for (so
= master_so_list (); so
; so
= so
->next
)
1557 if (so
->objfile
== objfile
)
1559 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1568 /* On some systems, the only way to recognize the link map entry for
1569 the main executable file is by looking at its name. Return
1570 non-zero iff SONAME matches one of the known main executable names. */
1573 match_main (const char *soname
)
1575 const char * const *mainp
;
1577 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
1579 if (strcmp (soname
, *mainp
) == 0)
1586 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1587 SVR4 run time loader. */
1590 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
1592 struct svr4_info
*info
= get_svr4_info ();
1594 return ((pc
>= info
->interp_text_sect_low
1595 && pc
< info
->interp_text_sect_high
)
1596 || (pc
>= info
->interp_plt_sect_low
1597 && pc
< info
->interp_plt_sect_high
)
1598 || in_plt_section (pc
)
1599 || in_gnu_ifunc_stub (pc
));
1602 /* Given an executable's ABFD and target, compute the entry-point
1606 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
1610 /* KevinB wrote ... for most targets, the address returned by
1611 bfd_get_start_address() is the entry point for the start
1612 function. But, for some targets, bfd_get_start_address() returns
1613 the address of a function descriptor from which the entry point
1614 address may be extracted. This address is extracted by
1615 gdbarch_convert_from_func_ptr_addr(). The method
1616 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1617 function for targets which don't use function descriptors. */
1618 addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
1619 bfd_get_start_address (abfd
),
1621 return gdbarch_addr_bits_remove (target_gdbarch (), addr
);
1624 /* A probe and its associated action. */
1626 struct probe_and_action
1631 /* The relocated address of the probe. */
1635 enum probe_action action
;
1638 /* Returns a hash code for the probe_and_action referenced by p. */
1641 hash_probe_and_action (const void *p
)
1643 const struct probe_and_action
*pa
= (const struct probe_and_action
*) p
;
1645 return (hashval_t
) pa
->address
;
1648 /* Returns non-zero if the probe_and_actions referenced by p1 and p2
1652 equal_probe_and_action (const void *p1
, const void *p2
)
1654 const struct probe_and_action
*pa1
= (const struct probe_and_action
*) p1
;
1655 const struct probe_and_action
*pa2
= (const struct probe_and_action
*) p2
;
1657 return pa1
->address
== pa2
->address
;
1660 /* Register a solib event probe and its associated action in the
1664 register_solib_event_probe (probe
*prob
, CORE_ADDR address
,
1665 enum probe_action action
)
1667 struct svr4_info
*info
= get_svr4_info ();
1668 struct probe_and_action lookup
, *pa
;
1671 /* Create the probes table, if necessary. */
1672 if (info
->probes_table
== NULL
)
1673 info
->probes_table
= htab_create_alloc (1, hash_probe_and_action
,
1674 equal_probe_and_action
,
1675 xfree
, xcalloc
, xfree
);
1678 lookup
.address
= address
;
1679 slot
= htab_find_slot (info
->probes_table
, &lookup
, INSERT
);
1680 gdb_assert (*slot
== HTAB_EMPTY_ENTRY
);
1682 pa
= XCNEW (struct probe_and_action
);
1684 pa
->address
= address
;
1685 pa
->action
= action
;
1690 /* Get the solib event probe at the specified location, and the
1691 action associated with it. Returns NULL if no solib event probe
1694 static struct probe_and_action
*
1695 solib_event_probe_at (struct svr4_info
*info
, CORE_ADDR address
)
1697 struct probe_and_action lookup
;
1700 lookup
.address
= address
;
1701 slot
= htab_find_slot (info
->probes_table
, &lookup
, NO_INSERT
);
1706 return (struct probe_and_action
*) *slot
;
1709 /* Decide what action to take when the specified solib event probe is
1712 static enum probe_action
1713 solib_event_probe_action (struct probe_and_action
*pa
)
1715 enum probe_action action
;
1716 unsigned probe_argc
= 0;
1717 struct frame_info
*frame
= get_current_frame ();
1719 action
= pa
->action
;
1720 if (action
== DO_NOTHING
|| action
== PROBES_INTERFACE_FAILED
)
1723 gdb_assert (action
== FULL_RELOAD
|| action
== UPDATE_OR_RELOAD
);
1725 /* Check that an appropriate number of arguments has been supplied.
1727 arg0: Lmid_t lmid (mandatory)
1728 arg1: struct r_debug *debug_base (mandatory)
1729 arg2: struct link_map *new (optional, for incremental updates) */
1732 probe_argc
= pa
->prob
->get_argument_count (frame
);
1734 CATCH (ex
, RETURN_MASK_ERROR
)
1736 exception_print (gdb_stderr
, ex
);
1741 /* If get_argument_count throws an exception, probe_argc will be set
1742 to zero. However, if pa->prob does not have arguments, then
1743 get_argument_count will succeed but probe_argc will also be zero.
1744 Both cases happen because of different things, but they are
1745 treated equally here: action will be set to
1746 PROBES_INTERFACE_FAILED. */
1747 if (probe_argc
== 2)
1748 action
= FULL_RELOAD
;
1749 else if (probe_argc
< 2)
1750 action
= PROBES_INTERFACE_FAILED
;
1755 /* Populate the shared object list by reading the entire list of
1756 shared objects from the inferior. Handle special cases relating
1757 to the first elements of the list. Returns nonzero on success. */
1760 solist_update_full (struct svr4_info
*info
)
1762 free_solib_list (info
);
1763 info
->solib_list
= svr4_current_sos_direct (info
);
1768 /* Update the shared object list starting from the link-map entry
1769 passed by the linker in the probe's third argument. Returns
1770 nonzero if the list was successfully updated, or zero to indicate
1774 solist_update_incremental (struct svr4_info
*info
, CORE_ADDR lm
)
1776 struct so_list
*tail
;
1779 /* svr4_current_sos_direct contains logic to handle a number of
1780 special cases relating to the first elements of the list. To
1781 avoid duplicating this logic we defer to solist_update_full
1782 if the list is empty. */
1783 if (info
->solib_list
== NULL
)
1786 /* Fall back to a full update if we are using a remote target
1787 that does not support incremental transfers. */
1788 if (info
->using_xfer
&& !target_augmented_libraries_svr4_read ())
1791 /* Walk to the end of the list. */
1792 for (tail
= info
->solib_list
; tail
->next
!= NULL
; tail
= tail
->next
)
1795 lm_info_svr4
*li
= (lm_info_svr4
*) tail
->lm_info
;
1796 prev_lm
= li
->lm_addr
;
1798 /* Read the new objects. */
1799 if (info
->using_xfer
)
1801 struct svr4_library_list library_list
;
1804 xsnprintf (annex
, sizeof (annex
), "start=%s;prev=%s",
1805 phex_nz (lm
, sizeof (lm
)),
1806 phex_nz (prev_lm
, sizeof (prev_lm
)));
1807 if (!svr4_current_sos_via_xfer_libraries (&library_list
, annex
))
1810 tail
->next
= library_list
.head
;
1814 struct so_list
**link
= &tail
->next
;
1816 /* IGNORE_FIRST may safely be set to zero here because the
1817 above check and deferral to solist_update_full ensures
1818 that this call to svr4_read_so_list will never see the
1820 if (!svr4_read_so_list (lm
, prev_lm
, &link
, 0))
1827 /* Disable the probes-based linker interface and revert to the
1828 original interface. We don't reset the breakpoints as the
1829 ones set up for the probes-based interface are adequate. */
1832 disable_probes_interface ()
1834 struct svr4_info
*info
= get_svr4_info ();
1836 warning (_("Probes-based dynamic linker interface failed.\n"
1837 "Reverting to original interface.\n"));
1839 free_probes_table (info
);
1840 free_solib_list (info
);
1843 /* Update the solib list as appropriate when using the
1844 probes-based linker interface. Do nothing if using the
1845 standard interface. */
1848 svr4_handle_solib_event (void)
1850 struct svr4_info
*info
= get_svr4_info ();
1851 struct probe_and_action
*pa
;
1852 enum probe_action action
;
1853 struct value
*val
= NULL
;
1854 CORE_ADDR pc
, debug_base
, lm
= 0;
1855 struct frame_info
*frame
= get_current_frame ();
1857 /* Do nothing if not using the probes interface. */
1858 if (info
->probes_table
== NULL
)
1861 /* If anything goes wrong we revert to the original linker
1863 auto cleanup
= make_scope_exit (disable_probes_interface
);
1865 pc
= regcache_read_pc (get_current_regcache ());
1866 pa
= solib_event_probe_at (info
, pc
);
1870 action
= solib_event_probe_action (pa
);
1871 if (action
== PROBES_INTERFACE_FAILED
)
1874 if (action
== DO_NOTHING
)
1880 /* evaluate_argument looks up symbols in the dynamic linker
1881 using find_pc_section. find_pc_section is accelerated by a cache
1882 called the section map. The section map is invalidated every
1883 time a shared library is loaded or unloaded, and if the inferior
1884 is generating a lot of shared library events then the section map
1885 will be updated every time svr4_handle_solib_event is called.
1886 We called find_pc_section in svr4_create_solib_event_breakpoints,
1887 so we can guarantee that the dynamic linker's sections are in the
1888 section map. We can therefore inhibit section map updates across
1889 these calls to evaluate_argument and save a lot of time. */
1891 scoped_restore inhibit_updates
1892 = inhibit_section_map_updates (current_program_space
);
1896 val
= pa
->prob
->evaluate_argument (1, frame
);
1898 CATCH (ex
, RETURN_MASK_ERROR
)
1900 exception_print (gdb_stderr
, ex
);
1908 debug_base
= value_as_address (val
);
1909 if (debug_base
== 0)
1912 /* Always locate the debug struct, in case it moved. */
1913 info
->debug_base
= 0;
1914 if (locate_base (info
) == 0)
1917 /* GDB does not currently support libraries loaded via dlmopen
1918 into namespaces other than the initial one. We must ignore
1919 any namespace other than the initial namespace here until
1920 support for this is added to GDB. */
1921 if (debug_base
!= info
->debug_base
)
1922 action
= DO_NOTHING
;
1924 if (action
== UPDATE_OR_RELOAD
)
1928 val
= pa
->prob
->evaluate_argument (2, frame
);
1930 CATCH (ex
, RETURN_MASK_ERROR
)
1932 exception_print (gdb_stderr
, ex
);
1938 lm
= value_as_address (val
);
1941 action
= FULL_RELOAD
;
1944 /* Resume section map updates. Closing the scope is
1948 if (action
== UPDATE_OR_RELOAD
)
1950 if (!solist_update_incremental (info
, lm
))
1951 action
= FULL_RELOAD
;
1954 if (action
== FULL_RELOAD
)
1956 if (!solist_update_full (info
))
1963 /* Helper function for svr4_update_solib_event_breakpoints. */
1966 svr4_update_solib_event_breakpoint (struct breakpoint
*b
, void *arg
)
1968 struct bp_location
*loc
;
1970 if (b
->type
!= bp_shlib_event
)
1972 /* Continue iterating. */
1976 for (loc
= b
->loc
; loc
!= NULL
; loc
= loc
->next
)
1978 struct svr4_info
*info
;
1979 struct probe_and_action
*pa
;
1981 info
= ((struct svr4_info
*)
1982 program_space_data (loc
->pspace
, solib_svr4_pspace_data
));
1983 if (info
== NULL
|| info
->probes_table
== NULL
)
1986 pa
= solib_event_probe_at (info
, loc
->address
);
1990 if (pa
->action
== DO_NOTHING
)
1992 if (b
->enable_state
== bp_disabled
&& stop_on_solib_events
)
1993 enable_breakpoint (b
);
1994 else if (b
->enable_state
== bp_enabled
&& !stop_on_solib_events
)
1995 disable_breakpoint (b
);
2001 /* Continue iterating. */
2005 /* Enable or disable optional solib event breakpoints as appropriate.
2006 Called whenever stop_on_solib_events is changed. */
2009 svr4_update_solib_event_breakpoints (void)
2011 iterate_over_breakpoints (svr4_update_solib_event_breakpoint
, NULL
);
2014 /* Create and register solib event breakpoints. PROBES is an array
2015 of NUM_PROBES elements, each of which is vector of probes. A
2016 solib event breakpoint will be created and registered for each
2020 svr4_create_probe_breakpoints (struct gdbarch
*gdbarch
,
2021 const std::vector
<probe
*> *probes
,
2022 struct objfile
*objfile
)
2024 for (int i
= 0; i
< NUM_PROBES
; i
++)
2026 enum probe_action action
= probe_info
[i
].action
;
2028 for (probe
*p
: probes
[i
])
2030 CORE_ADDR address
= p
->get_relocated_address (objfile
);
2032 create_solib_event_breakpoint (gdbarch
, address
);
2033 register_solib_event_probe (p
, address
, action
);
2037 svr4_update_solib_event_breakpoints ();
2040 /* Both the SunOS and the SVR4 dynamic linkers call a marker function
2041 before and after mapping and unmapping shared libraries. The sole
2042 purpose of this method is to allow debuggers to set a breakpoint so
2043 they can track these changes.
2045 Some versions of the glibc dynamic linker contain named probes
2046 to allow more fine grained stopping. Given the address of the
2047 original marker function, this function attempts to find these
2048 probes, and if found, sets breakpoints on those instead. If the
2049 probes aren't found, a single breakpoint is set on the original
2053 svr4_create_solib_event_breakpoints (struct gdbarch
*gdbarch
,
2056 struct obj_section
*os
;
2058 os
= find_pc_section (address
);
2063 for (with_prefix
= 0; with_prefix
<= 1; with_prefix
++)
2065 std::vector
<probe
*> probes
[NUM_PROBES
];
2066 int all_probes_found
= 1;
2067 int checked_can_use_probe_arguments
= 0;
2069 for (int i
= 0; i
< NUM_PROBES
; i
++)
2071 const char *name
= probe_info
[i
].name
;
2075 /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4
2076 shipped with an early version of the probes code in
2077 which the probes' names were prefixed with "rtld_"
2078 and the "map_failed" probe did not exist. The
2079 locations of the probes are otherwise the same, so
2080 we check for probes with prefixed names if probes
2081 with unprefixed names are not present. */
2084 xsnprintf (buf
, sizeof (buf
), "rtld_%s", name
);
2088 probes
[i
] = find_probes_in_objfile (os
->objfile
, "rtld", name
);
2090 /* The "map_failed" probe did not exist in early
2091 versions of the probes code in which the probes'
2092 names were prefixed with "rtld_". */
2093 if (strcmp (name
, "rtld_map_failed") == 0)
2096 if (probes
[i
].empty ())
2098 all_probes_found
= 0;
2102 /* Ensure probe arguments can be evaluated. */
2103 if (!checked_can_use_probe_arguments
)
2106 if (!p
->can_evaluate_arguments ())
2108 all_probes_found
= 0;
2111 checked_can_use_probe_arguments
= 1;
2115 if (all_probes_found
)
2116 svr4_create_probe_breakpoints (gdbarch
, probes
, os
->objfile
);
2118 if (all_probes_found
)
2123 create_solib_event_breakpoint (gdbarch
, address
);
2126 /* Helper function for gdb_bfd_lookup_symbol. */
2129 cmp_name_and_sec_flags (const asymbol
*sym
, const void *data
)
2131 return (strcmp (sym
->name
, (const char *) data
) == 0
2132 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0);
2134 /* Arrange for dynamic linker to hit breakpoint.
2136 Both the SunOS and the SVR4 dynamic linkers have, as part of their
2137 debugger interface, support for arranging for the inferior to hit
2138 a breakpoint after mapping in the shared libraries. This function
2139 enables that breakpoint.
2141 For SunOS, there is a special flag location (in_debugger) which we
2142 set to 1. When the dynamic linker sees this flag set, it will set
2143 a breakpoint at a location known only to itself, after saving the
2144 original contents of that place and the breakpoint address itself,
2145 in it's own internal structures. When we resume the inferior, it
2146 will eventually take a SIGTRAP when it runs into the breakpoint.
2147 We handle this (in a different place) by restoring the contents of
2148 the breakpointed location (which is only known after it stops),
2149 chasing around to locate the shared libraries that have been
2150 loaded, then resuming.
2152 For SVR4, the debugger interface structure contains a member (r_brk)
2153 which is statically initialized at the time the shared library is
2154 built, to the offset of a function (_r_debug_state) which is guaran-
2155 teed to be called once before mapping in a library, and again when
2156 the mapping is complete. At the time we are examining this member,
2157 it contains only the unrelocated offset of the function, so we have
2158 to do our own relocation. Later, when the dynamic linker actually
2159 runs, it relocates r_brk to be the actual address of _r_debug_state().
2161 The debugger interface structure also contains an enumeration which
2162 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
2163 depending upon whether or not the library is being mapped or unmapped,
2164 and then set to RT_CONSISTENT after the library is mapped/unmapped. */
2167 enable_break (struct svr4_info
*info
, int from_tty
)
2169 struct bound_minimal_symbol msymbol
;
2170 const char * const *bkpt_namep
;
2171 asection
*interp_sect
;
2174 info
->interp_text_sect_low
= info
->interp_text_sect_high
= 0;
2175 info
->interp_plt_sect_low
= info
->interp_plt_sect_high
= 0;
2177 /* If we already have a shared library list in the target, and
2178 r_debug contains r_brk, set the breakpoint there - this should
2179 mean r_brk has already been relocated. Assume the dynamic linker
2180 is the object containing r_brk. */
2182 solib_add (NULL
, from_tty
, auto_solib_add
);
2184 if (info
->debug_base
&& solib_svr4_r_map (info
) != 0)
2185 sym_addr
= solib_svr4_r_brk (info
);
2189 struct obj_section
*os
;
2191 sym_addr
= gdbarch_addr_bits_remove
2193 gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2195 current_top_target ()));
2197 /* On at least some versions of Solaris there's a dynamic relocation
2198 on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
2199 we get control before the dynamic linker has self-relocated.
2200 Check if SYM_ADDR is in a known section, if it is assume we can
2201 trust its value. This is just a heuristic though, it could go away
2202 or be replaced if it's getting in the way.
2204 On ARM we need to know whether the ISA of rtld_db_dlactivity (or
2205 however it's spelled in your particular system) is ARM or Thumb.
2206 That knowledge is encoded in the address, if it's Thumb the low bit
2207 is 1. However, we've stripped that info above and it's not clear
2208 what all the consequences are of passing a non-addr_bits_remove'd
2209 address to svr4_create_solib_event_breakpoints. The call to
2210 find_pc_section verifies we know about the address and have some
2211 hope of computing the right kind of breakpoint to use (via
2212 symbol info). It does mean that GDB needs to be pointed at a
2213 non-stripped version of the dynamic linker in order to obtain
2214 information it already knows about. Sigh. */
2216 os
= find_pc_section (sym_addr
);
2219 /* Record the relocated start and end address of the dynamic linker
2220 text and plt section for svr4_in_dynsym_resolve_code. */
2222 CORE_ADDR load_addr
;
2224 tmp_bfd
= os
->objfile
->obfd
;
2225 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
2226 SECT_OFF_TEXT (os
->objfile
));
2228 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
2231 info
->interp_text_sect_low
=
2232 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
2233 info
->interp_text_sect_high
=
2234 info
->interp_text_sect_low
2235 + bfd_section_size (tmp_bfd
, interp_sect
);
2237 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
2240 info
->interp_plt_sect_low
=
2241 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
2242 info
->interp_plt_sect_high
=
2243 info
->interp_plt_sect_low
2244 + bfd_section_size (tmp_bfd
, interp_sect
);
2247 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2252 /* Find the program interpreter; if not found, warn the user and drop
2253 into the old breakpoint at symbol code. */
2254 gdb::optional
<gdb::byte_vector
> interp_name_holder
2255 = find_program_interpreter ();
2256 if (interp_name_holder
)
2258 const char *interp_name
= (const char *) interp_name_holder
->data ();
2259 CORE_ADDR load_addr
= 0;
2260 int load_addr_found
= 0;
2261 int loader_found_in_list
= 0;
2263 struct target_ops
*tmp_bfd_target
;
2267 /* Now we need to figure out where the dynamic linker was
2268 loaded so that we can load its symbols and place a breakpoint
2269 in the dynamic linker itself.
2271 This address is stored on the stack. However, I've been unable
2272 to find any magic formula to find it for Solaris (appears to
2273 be trivial on GNU/Linux). Therefore, we have to try an alternate
2274 mechanism to find the dynamic linker's base address. */
2276 gdb_bfd_ref_ptr tmp_bfd
;
2279 tmp_bfd
= solib_bfd_open (interp_name
);
2281 CATCH (ex
, RETURN_MASK_ALL
)
2286 if (tmp_bfd
== NULL
)
2287 goto bkpt_at_symbol
;
2289 /* Now convert the TMP_BFD into a target. That way target, as
2290 well as BFD operations can be used. target_bfd_reopen
2291 acquires its own reference. */
2292 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
.get ());
2294 /* On a running target, we can get the dynamic linker's base
2295 address from the shared library table. */
2296 so
= master_so_list ();
2299 if (svr4_same_1 (interp_name
, so
->so_original_name
))
2301 load_addr_found
= 1;
2302 loader_found_in_list
= 1;
2303 load_addr
= lm_addr_check (so
, tmp_bfd
.get ());
2309 /* If we were not able to find the base address of the loader
2310 from our so_list, then try using the AT_BASE auxilliary entry. */
2311 if (!load_addr_found
)
2312 if (target_auxv_search (current_top_target (), AT_BASE
, &load_addr
) > 0)
2314 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
2316 /* Ensure LOAD_ADDR has proper sign in its possible upper bits so
2317 that `+ load_addr' will overflow CORE_ADDR width not creating
2318 invalid addresses like 0x101234567 for 32bit inferiors on 64bit
2321 if (addr_bit
< (sizeof (CORE_ADDR
) * HOST_CHAR_BIT
))
2323 CORE_ADDR space_size
= (CORE_ADDR
) 1 << addr_bit
;
2324 CORE_ADDR tmp_entry_point
= exec_entry_point (tmp_bfd
.get (),
2327 gdb_assert (load_addr
< space_size
);
2329 /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked
2330 64bit ld.so with 32bit executable, it should not happen. */
2332 if (tmp_entry_point
< space_size
2333 && tmp_entry_point
+ load_addr
>= space_size
)
2334 load_addr
-= space_size
;
2337 load_addr_found
= 1;
2340 /* Otherwise we find the dynamic linker's base address by examining
2341 the current pc (which should point at the entry point for the
2342 dynamic linker) and subtracting the offset of the entry point.
2344 This is more fragile than the previous approaches, but is a good
2345 fallback method because it has actually been working well in
2347 if (!load_addr_found
)
2349 struct regcache
*regcache
2350 = get_thread_arch_regcache (inferior_ptid
, target_gdbarch ());
2352 load_addr
= (regcache_read_pc (regcache
)
2353 - exec_entry_point (tmp_bfd
.get (), tmp_bfd_target
));
2356 if (!loader_found_in_list
)
2358 info
->debug_loader_name
= xstrdup (interp_name
);
2359 info
->debug_loader_offset_p
= 1;
2360 info
->debug_loader_offset
= load_addr
;
2361 solib_add (NULL
, from_tty
, auto_solib_add
);
2364 /* Record the relocated start and end address of the dynamic linker
2365 text and plt section for svr4_in_dynsym_resolve_code. */
2366 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".text");
2369 info
->interp_text_sect_low
=
2370 bfd_section_vma (tmp_bfd
.get (), interp_sect
) + load_addr
;
2371 info
->interp_text_sect_high
=
2372 info
->interp_text_sect_low
2373 + bfd_section_size (tmp_bfd
.get (), interp_sect
);
2375 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".plt");
2378 info
->interp_plt_sect_low
=
2379 bfd_section_vma (tmp_bfd
.get (), interp_sect
) + load_addr
;
2380 info
->interp_plt_sect_high
=
2381 info
->interp_plt_sect_low
2382 + bfd_section_size (tmp_bfd
.get (), interp_sect
);
2385 /* Now try to set a breakpoint in the dynamic linker. */
2386 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2388 sym_addr
= gdb_bfd_lookup_symbol (tmp_bfd
.get (),
2389 cmp_name_and_sec_flags
,
2396 /* Convert 'sym_addr' from a function pointer to an address.
2397 Because we pass tmp_bfd_target instead of the current
2398 target, this will always produce an unrelocated value. */
2399 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2403 /* We're done with both the temporary bfd and target. Closing
2404 the target closes the underlying bfd, because it holds the
2405 only remaining reference. */
2406 target_close (tmp_bfd_target
);
2410 svr4_create_solib_event_breakpoints (target_gdbarch (),
2411 load_addr
+ sym_addr
);
2415 /* For whatever reason we couldn't set a breakpoint in the dynamic
2416 linker. Warn and drop into the old code. */
2418 warning (_("Unable to find dynamic linker breakpoint function.\n"
2419 "GDB will be unable to debug shared library initializers\n"
2420 "and track explicitly loaded dynamic code."));
2423 /* Scan through the lists of symbols, trying to look up the symbol and
2424 set a breakpoint there. Terminate loop when we/if we succeed. */
2426 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2428 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
2429 if ((msymbol
.minsym
!= NULL
)
2430 && (BMSYMBOL_VALUE_ADDRESS (msymbol
) != 0))
2432 sym_addr
= BMSYMBOL_VALUE_ADDRESS (msymbol
);
2433 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2435 current_top_target ());
2436 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2441 if (interp_name_holder
&& !current_inferior ()->attach_flag
)
2443 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2445 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
2446 if ((msymbol
.minsym
!= NULL
)
2447 && (BMSYMBOL_VALUE_ADDRESS (msymbol
) != 0))
2449 sym_addr
= BMSYMBOL_VALUE_ADDRESS (msymbol
);
2450 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2452 current_top_target ());
2453 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2461 /* Read the ELF program headers from ABFD. */
2463 static gdb::optional
<gdb::byte_vector
>
2464 read_program_headers_from_bfd (bfd
*abfd
)
2466 Elf_Internal_Ehdr
*ehdr
= elf_elfheader (abfd
);
2467 int phdrs_size
= ehdr
->e_phnum
* ehdr
->e_phentsize
;
2468 if (phdrs_size
== 0)
2471 gdb::byte_vector
buf (phdrs_size
);
2472 if (bfd_seek (abfd
, ehdr
->e_phoff
, SEEK_SET
) != 0
2473 || bfd_bread (buf
.data (), phdrs_size
, abfd
) != phdrs_size
)
2479 /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior
2480 exec_bfd. Otherwise return 0.
2482 We relocate all of the sections by the same amount. This
2483 behavior is mandated by recent editions of the System V ABI.
2484 According to the System V Application Binary Interface,
2485 Edition 4.1, page 5-5:
2487 ... Though the system chooses virtual addresses for
2488 individual processes, it maintains the segments' relative
2489 positions. Because position-independent code uses relative
2490 addressesing between segments, the difference between
2491 virtual addresses in memory must match the difference
2492 between virtual addresses in the file. The difference
2493 between the virtual address of any segment in memory and
2494 the corresponding virtual address in the file is thus a
2495 single constant value for any one executable or shared
2496 object in a given process. This difference is the base
2497 address. One use of the base address is to relocate the
2498 memory image of the program during dynamic linking.
2500 The same language also appears in Edition 4.0 of the System V
2501 ABI and is left unspecified in some of the earlier editions.
2503 Decide if the objfile needs to be relocated. As indicated above, we will
2504 only be here when execution is stopped. But during attachment PC can be at
2505 arbitrary address therefore regcache_read_pc can be misleading (contrary to
2506 the auxv AT_ENTRY value). Moreover for executable with interpreter section
2507 regcache_read_pc would point to the interpreter and not the main executable.
2509 So, to summarize, relocations are necessary when the start address obtained
2510 from the executable is different from the address in auxv AT_ENTRY entry.
2512 [ The astute reader will note that we also test to make sure that
2513 the executable in question has the DYNAMIC flag set. It is my
2514 opinion that this test is unnecessary (undesirable even). It
2515 was added to avoid inadvertent relocation of an executable
2516 whose e_type member in the ELF header is not ET_DYN. There may
2517 be a time in the future when it is desirable to do relocations
2518 on other types of files as well in which case this condition
2519 should either be removed or modified to accomodate the new file
2520 type. - Kevin, Nov 2000. ] */
2523 svr4_exec_displacement (CORE_ADDR
*displacementp
)
2525 /* ENTRY_POINT is a possible function descriptor - before
2526 a call to gdbarch_convert_from_func_ptr_addr. */
2527 CORE_ADDR entry_point
, exec_displacement
;
2529 if (exec_bfd
== NULL
)
2532 /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries
2533 being executed themselves and PIE (Position Independent Executable)
2534 executables are ET_DYN. */
2536 if ((bfd_get_file_flags (exec_bfd
) & DYNAMIC
) == 0)
2539 if (target_auxv_search (current_top_target (), AT_ENTRY
, &entry_point
) <= 0)
2542 exec_displacement
= entry_point
- bfd_get_start_address (exec_bfd
);
2544 /* Verify the EXEC_DISPLACEMENT candidate complies with the required page
2545 alignment. It is cheaper than the program headers comparison below. */
2547 if (bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
2549 const struct elf_backend_data
*elf
= get_elf_backend_data (exec_bfd
);
2551 /* p_align of PT_LOAD segments does not specify any alignment but
2552 only congruency of addresses:
2553 p_offset % p_align == p_vaddr % p_align
2554 Kernel is free to load the executable with lower alignment. */
2556 if ((exec_displacement
& (elf
->minpagesize
- 1)) != 0)
2560 /* Verify that the auxilliary vector describes the same file as exec_bfd, by
2561 comparing their program headers. If the program headers in the auxilliary
2562 vector do not match the program headers in the executable, then we are
2563 looking at a different file than the one used by the kernel - for
2564 instance, "gdb program" connected to "gdbserver :PORT ld.so program". */
2566 if (bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
2568 /* Be optimistic and return 0 only if GDB was able to verify the headers
2569 really do not match. */
2572 gdb::optional
<gdb::byte_vector
> phdrs_target
2573 = read_program_header (-1, &arch_size
, NULL
);
2574 gdb::optional
<gdb::byte_vector
> phdrs_binary
2575 = read_program_headers_from_bfd (exec_bfd
);
2576 if (phdrs_target
&& phdrs_binary
)
2578 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
2580 /* We are dealing with three different addresses. EXEC_BFD
2581 represents current address in on-disk file. target memory content
2582 may be different from EXEC_BFD as the file may have been prelinked
2583 to a different address after the executable has been loaded.
2584 Moreover the address of placement in target memory can be
2585 different from what the program headers in target memory say -
2586 this is the goal of PIE.
2588 Detected DISPLACEMENT covers both the offsets of PIE placement and
2589 possible new prelink performed after start of the program. Here
2590 relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
2591 content offset for the verification purpose. */
2593 if (phdrs_target
->size () != phdrs_binary
->size ()
2594 || bfd_get_arch_size (exec_bfd
) != arch_size
)
2596 else if (arch_size
== 32
2597 && phdrs_target
->size () >= sizeof (Elf32_External_Phdr
)
2598 && phdrs_target
->size () % sizeof (Elf32_External_Phdr
) == 0)
2600 Elf_Internal_Ehdr
*ehdr2
= elf_tdata (exec_bfd
)->elf_header
;
2601 Elf_Internal_Phdr
*phdr2
= elf_tdata (exec_bfd
)->phdr
;
2602 CORE_ADDR displacement
= 0;
2605 /* DISPLACEMENT could be found more easily by the difference of
2606 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2607 already have enough information to compute that displacement
2608 with what we've read. */
2610 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2611 if (phdr2
[i
].p_type
== PT_LOAD
)
2613 Elf32_External_Phdr
*phdrp
;
2614 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2615 CORE_ADDR vaddr
, paddr
;
2616 CORE_ADDR displacement_vaddr
= 0;
2617 CORE_ADDR displacement_paddr
= 0;
2619 phdrp
= &((Elf32_External_Phdr
*) phdrs_target
->data ())[i
];
2620 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2621 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2623 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2625 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2627 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2629 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2631 if (displacement_vaddr
== displacement_paddr
)
2632 displacement
= displacement_vaddr
;
2637 /* Now compare program headers from the target and the binary
2638 with optional DISPLACEMENT. */
2641 i
< phdrs_target
->size () / sizeof (Elf32_External_Phdr
);
2644 Elf32_External_Phdr
*phdrp
;
2645 Elf32_External_Phdr
*phdr2p
;
2646 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2647 CORE_ADDR vaddr
, paddr
;
2648 asection
*plt2_asect
;
2650 phdrp
= &((Elf32_External_Phdr
*) phdrs_target
->data ())[i
];
2651 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2652 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2653 phdr2p
= &((Elf32_External_Phdr
*) phdrs_binary
->data ())[i
];
2655 /* PT_GNU_STACK is an exception by being never relocated by
2656 prelink as its addresses are always zero. */
2658 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2661 /* Check also other adjustment combinations - PR 11786. */
2663 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2665 vaddr
-= displacement
;
2666 store_unsigned_integer (buf_vaddr_p
, 4, byte_order
, vaddr
);
2668 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2670 paddr
-= displacement
;
2671 store_unsigned_integer (buf_paddr_p
, 4, byte_order
, paddr
);
2673 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2676 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2677 CentOS-5 has problems with filesz, memsz as well.
2678 Strip also modifies memsz of PT_TLS.
2680 if (phdr2
[i
].p_type
== PT_GNU_RELRO
2681 || phdr2
[i
].p_type
== PT_TLS
)
2683 Elf32_External_Phdr tmp_phdr
= *phdrp
;
2684 Elf32_External_Phdr tmp_phdr2
= *phdr2p
;
2686 memset (tmp_phdr
.p_filesz
, 0, 4);
2687 memset (tmp_phdr
.p_memsz
, 0, 4);
2688 memset (tmp_phdr
.p_flags
, 0, 4);
2689 memset (tmp_phdr
.p_align
, 0, 4);
2690 memset (tmp_phdr2
.p_filesz
, 0, 4);
2691 memset (tmp_phdr2
.p_memsz
, 0, 4);
2692 memset (tmp_phdr2
.p_flags
, 0, 4);
2693 memset (tmp_phdr2
.p_align
, 0, 4);
2695 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2700 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2701 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2705 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2708 content2
= (bfd_get_section_flags (exec_bfd
, plt2_asect
)
2709 & SEC_HAS_CONTENTS
) != 0;
2711 filesz
= extract_unsigned_integer (buf_filesz_p
, 4,
2714 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2715 FILESZ is from the in-memory image. */
2717 filesz
+= bfd_get_section_size (plt2_asect
);
2719 filesz
-= bfd_get_section_size (plt2_asect
);
2721 store_unsigned_integer (buf_filesz_p
, 4, byte_order
,
2724 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2731 else if (arch_size
== 64
2732 && phdrs_target
->size () >= sizeof (Elf64_External_Phdr
)
2733 && phdrs_target
->size () % sizeof (Elf64_External_Phdr
) == 0)
2735 Elf_Internal_Ehdr
*ehdr2
= elf_tdata (exec_bfd
)->elf_header
;
2736 Elf_Internal_Phdr
*phdr2
= elf_tdata (exec_bfd
)->phdr
;
2737 CORE_ADDR displacement
= 0;
2740 /* DISPLACEMENT could be found more easily by the difference of
2741 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2742 already have enough information to compute that displacement
2743 with what we've read. */
2745 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2746 if (phdr2
[i
].p_type
== PT_LOAD
)
2748 Elf64_External_Phdr
*phdrp
;
2749 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2750 CORE_ADDR vaddr
, paddr
;
2751 CORE_ADDR displacement_vaddr
= 0;
2752 CORE_ADDR displacement_paddr
= 0;
2754 phdrp
= &((Elf64_External_Phdr
*) phdrs_target
->data ())[i
];
2755 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2756 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2758 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2760 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2762 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2764 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2766 if (displacement_vaddr
== displacement_paddr
)
2767 displacement
= displacement_vaddr
;
2772 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2775 i
< phdrs_target
->size () / sizeof (Elf64_External_Phdr
);
2778 Elf64_External_Phdr
*phdrp
;
2779 Elf64_External_Phdr
*phdr2p
;
2780 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2781 CORE_ADDR vaddr
, paddr
;
2782 asection
*plt2_asect
;
2784 phdrp
= &((Elf64_External_Phdr
*) phdrs_target
->data ())[i
];
2785 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2786 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2787 phdr2p
= &((Elf64_External_Phdr
*) phdrs_binary
->data ())[i
];
2789 /* PT_GNU_STACK is an exception by being never relocated by
2790 prelink as its addresses are always zero. */
2792 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2795 /* Check also other adjustment combinations - PR 11786. */
2797 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2799 vaddr
-= displacement
;
2800 store_unsigned_integer (buf_vaddr_p
, 8, byte_order
, vaddr
);
2802 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2804 paddr
-= displacement
;
2805 store_unsigned_integer (buf_paddr_p
, 8, byte_order
, paddr
);
2807 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2810 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2811 CentOS-5 has problems with filesz, memsz as well.
2812 Strip also modifies memsz of PT_TLS.
2814 if (phdr2
[i
].p_type
== PT_GNU_RELRO
2815 || phdr2
[i
].p_type
== PT_TLS
)
2817 Elf64_External_Phdr tmp_phdr
= *phdrp
;
2818 Elf64_External_Phdr tmp_phdr2
= *phdr2p
;
2820 memset (tmp_phdr
.p_filesz
, 0, 8);
2821 memset (tmp_phdr
.p_memsz
, 0, 8);
2822 memset (tmp_phdr
.p_flags
, 0, 4);
2823 memset (tmp_phdr
.p_align
, 0, 8);
2824 memset (tmp_phdr2
.p_filesz
, 0, 8);
2825 memset (tmp_phdr2
.p_memsz
, 0, 8);
2826 memset (tmp_phdr2
.p_flags
, 0, 4);
2827 memset (tmp_phdr2
.p_align
, 0, 8);
2829 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2834 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2835 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2839 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2842 content2
= (bfd_get_section_flags (exec_bfd
, plt2_asect
)
2843 & SEC_HAS_CONTENTS
) != 0;
2845 filesz
= extract_unsigned_integer (buf_filesz_p
, 8,
2848 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2849 FILESZ is from the in-memory image. */
2851 filesz
+= bfd_get_section_size (plt2_asect
);
2853 filesz
-= bfd_get_section_size (plt2_asect
);
2855 store_unsigned_integer (buf_filesz_p
, 8, byte_order
,
2858 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2872 /* It can be printed repeatedly as there is no easy way to check
2873 the executable symbols/file has been already relocated to
2876 printf_unfiltered (_("Using PIE (Position Independent Executable) "
2877 "displacement %s for \"%s\".\n"),
2878 paddress (target_gdbarch (), exec_displacement
),
2879 bfd_get_filename (exec_bfd
));
2882 *displacementp
= exec_displacement
;
2886 /* Relocate the main executable. This function should be called upon
2887 stopping the inferior process at the entry point to the program.
2888 The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
2889 different, the main executable is relocated by the proper amount. */
2892 svr4_relocate_main_executable (void)
2894 CORE_ADDR displacement
;
2896 /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS
2897 probably contains the offsets computed using the PIE displacement
2898 from the previous run, which of course are irrelevant for this run.
2899 So we need to determine the new PIE displacement and recompute the
2900 section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS
2901 already contains pre-computed offsets.
2903 If we cannot compute the PIE displacement, either:
2905 - The executable is not PIE.
2907 - SYMFILE_OBJFILE does not match the executable started in the target.
2908 This can happen for main executable symbols loaded at the host while
2909 `ld.so --ld-args main-executable' is loaded in the target.
2911 Then we leave the section offsets untouched and use them as is for
2914 - These section offsets were properly reset earlier, and thus
2915 already contain the correct values. This can happen for instance
2916 when reconnecting via the remote protocol to a target that supports
2917 the `qOffsets' packet.
2919 - The section offsets were not reset earlier, and the best we can
2920 hope is that the old offsets are still applicable to the new run. */
2922 if (! svr4_exec_displacement (&displacement
))
2925 /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file
2928 if (symfile_objfile
)
2930 struct section_offsets
*new_offsets
;
2933 new_offsets
= XALLOCAVEC (struct section_offsets
,
2934 symfile_objfile
->num_sections
);
2936 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
2937 new_offsets
->offsets
[i
] = displacement
;
2939 objfile_relocate (symfile_objfile
, new_offsets
);
2945 for (asect
= exec_bfd
->sections
; asect
!= NULL
; asect
= asect
->next
)
2946 exec_set_section_address (bfd_get_filename (exec_bfd
), asect
->index
,
2947 (bfd_section_vma (exec_bfd
, asect
)
2952 /* Implement the "create_inferior_hook" target_solib_ops method.
2954 For SVR4 executables, this first instruction is either the first
2955 instruction in the dynamic linker (for dynamically linked
2956 executables) or the instruction at "start" for statically linked
2957 executables. For dynamically linked executables, the system
2958 first exec's /lib/libc.so.N, which contains the dynamic linker,
2959 and starts it running. The dynamic linker maps in any needed
2960 shared libraries, maps in the actual user executable, and then
2961 jumps to "start" in the user executable.
2963 We can arrange to cooperate with the dynamic linker to discover the
2964 names of shared libraries that are dynamically linked, and the base
2965 addresses to which they are linked.
2967 This function is responsible for discovering those names and
2968 addresses, and saving sufficient information about them to allow
2969 their symbols to be read at a later time. */
2972 svr4_solib_create_inferior_hook (int from_tty
)
2974 struct svr4_info
*info
;
2976 info
= get_svr4_info ();
2978 /* Clear the probes-based interface's state. */
2979 free_probes_table (info
);
2980 free_solib_list (info
);
2982 /* Relocate the main executable if necessary. */
2983 svr4_relocate_main_executable ();
2985 /* No point setting a breakpoint in the dynamic linker if we can't
2986 hit it (e.g., a core file, or a trace file). */
2987 if (!target_has_execution
)
2990 if (!svr4_have_link_map_offsets ())
2993 if (!enable_break (info
, from_tty
))
2998 svr4_clear_solib (void)
3000 struct svr4_info
*info
;
3002 info
= get_svr4_info ();
3003 info
->debug_base
= 0;
3004 info
->debug_loader_offset_p
= 0;
3005 info
->debug_loader_offset
= 0;
3006 xfree (info
->debug_loader_name
);
3007 info
->debug_loader_name
= NULL
;
3010 /* Clear any bits of ADDR that wouldn't fit in a target-format
3011 data pointer. "Data pointer" here refers to whatever sort of
3012 address the dynamic linker uses to manage its sections. At the
3013 moment, we don't support shared libraries on any processors where
3014 code and data pointers are different sizes.
3016 This isn't really the right solution. What we really need here is
3017 a way to do arithmetic on CORE_ADDR values that respects the
3018 natural pointer/address correspondence. (For example, on the MIPS,
3019 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
3020 sign-extend the value. There, simply truncating the bits above
3021 gdbarch_ptr_bit, as we do below, is no good.) This should probably
3022 be a new gdbarch method or something. */
3024 svr4_truncate_ptr (CORE_ADDR addr
)
3026 if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR
) * 8)
3027 /* We don't need to truncate anything, and the bit twiddling below
3028 will fail due to overflow problems. */
3031 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1);
3036 svr4_relocate_section_addresses (struct so_list
*so
,
3037 struct target_section
*sec
)
3039 bfd
*abfd
= sec
->the_bfd_section
->owner
;
3041 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ lm_addr_check (so
, abfd
));
3042 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ lm_addr_check (so
, abfd
));
3046 /* Architecture-specific operations. */
3048 /* Per-architecture data key. */
3049 static struct gdbarch_data
*solib_svr4_data
;
3051 struct solib_svr4_ops
3053 /* Return a description of the layout of `struct link_map'. */
3054 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
3057 /* Return a default for the architecture-specific operations. */
3060 solib_svr4_init (struct obstack
*obstack
)
3062 struct solib_svr4_ops
*ops
;
3064 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
3065 ops
->fetch_link_map_offsets
= NULL
;
3069 /* Set the architecture-specific `struct link_map_offsets' fetcher for
3070 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
3073 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
3074 struct link_map_offsets
*(*flmo
) (void))
3076 struct solib_svr4_ops
*ops
3077 = (struct solib_svr4_ops
*) gdbarch_data (gdbarch
, solib_svr4_data
);
3079 ops
->fetch_link_map_offsets
= flmo
;
3081 set_solib_ops (gdbarch
, &svr4_so_ops
);
3084 /* Fetch a link_map_offsets structure using the architecture-specific
3085 `struct link_map_offsets' fetcher. */
3087 static struct link_map_offsets
*
3088 svr4_fetch_link_map_offsets (void)
3090 struct solib_svr4_ops
*ops
3091 = (struct solib_svr4_ops
*) gdbarch_data (target_gdbarch (),
3094 gdb_assert (ops
->fetch_link_map_offsets
);
3095 return ops
->fetch_link_map_offsets ();
3098 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
3101 svr4_have_link_map_offsets (void)
3103 struct solib_svr4_ops
*ops
3104 = (struct solib_svr4_ops
*) gdbarch_data (target_gdbarch (),
3107 return (ops
->fetch_link_map_offsets
!= NULL
);
3111 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
3112 `struct r_debug' and a `struct link_map' that are binary compatible
3113 with the origional SVR4 implementation. */
3115 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3116 for an ILP32 SVR4 system. */
3118 struct link_map_offsets
*
3119 svr4_ilp32_fetch_link_map_offsets (void)
3121 static struct link_map_offsets lmo
;
3122 static struct link_map_offsets
*lmp
= NULL
;
3128 lmo
.r_version_offset
= 0;
3129 lmo
.r_version_size
= 4;
3130 lmo
.r_map_offset
= 4;
3131 lmo
.r_brk_offset
= 8;
3132 lmo
.r_ldsomap_offset
= 20;
3134 /* Everything we need is in the first 20 bytes. */
3135 lmo
.link_map_size
= 20;
3136 lmo
.l_addr_offset
= 0;
3137 lmo
.l_name_offset
= 4;
3138 lmo
.l_ld_offset
= 8;
3139 lmo
.l_next_offset
= 12;
3140 lmo
.l_prev_offset
= 16;
3146 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3147 for an LP64 SVR4 system. */
3149 struct link_map_offsets
*
3150 svr4_lp64_fetch_link_map_offsets (void)
3152 static struct link_map_offsets lmo
;
3153 static struct link_map_offsets
*lmp
= NULL
;
3159 lmo
.r_version_offset
= 0;
3160 lmo
.r_version_size
= 4;
3161 lmo
.r_map_offset
= 8;
3162 lmo
.r_brk_offset
= 16;
3163 lmo
.r_ldsomap_offset
= 40;
3165 /* Everything we need is in the first 40 bytes. */
3166 lmo
.link_map_size
= 40;
3167 lmo
.l_addr_offset
= 0;
3168 lmo
.l_name_offset
= 8;
3169 lmo
.l_ld_offset
= 16;
3170 lmo
.l_next_offset
= 24;
3171 lmo
.l_prev_offset
= 32;
3178 struct target_so_ops svr4_so_ops
;
3180 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
3181 different rule for symbol lookup. The lookup begins here in the DSO, not in
3182 the main executable. */
3184 static struct block_symbol
3185 elf_lookup_lib_symbol (struct objfile
*objfile
,
3187 const domain_enum domain
)
3191 if (objfile
== symfile_objfile
)
3195 /* OBJFILE should have been passed as the non-debug one. */
3196 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
3198 abfd
= objfile
->obfd
;
3201 if (abfd
== NULL
|| scan_dyntag (DT_SYMBOLIC
, abfd
, NULL
, NULL
) != 1)
3202 return (struct block_symbol
) {NULL
, NULL
};
3204 return lookup_global_symbol_from_objfile (objfile
, name
, domain
);
3208 _initialize_svr4_solib (void)
3210 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
3211 solib_svr4_pspace_data
3212 = register_program_space_data_with_cleanup (NULL
, svr4_pspace_data_cleanup
);
3214 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
3215 svr4_so_ops
.free_so
= svr4_free_so
;
3216 svr4_so_ops
.clear_so
= svr4_clear_so
;
3217 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
3218 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
3219 svr4_so_ops
.current_sos
= svr4_current_sos
;
3220 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
3221 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
3222 svr4_so_ops
.bfd_open
= solib_bfd_open
;
3223 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
3224 svr4_so_ops
.same
= svr4_same
;
3225 svr4_so_ops
.keep_data_in_core
= svr4_keep_data_in_core
;
3226 svr4_so_ops
.update_breakpoints
= svr4_update_solib_event_breakpoints
;
3227 svr4_so_ops
.handle_event
= svr4_handle_solib_event
;