1 /* Handle SVR4 shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990-2017 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"
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 sparc64, but with
157 different locations. */
158 if (strcmp (gdb_so_name
, "/usr/lib/sparcv9/ld.so.1") == 0
159 && strcmp (inferior_so_name
, "/lib/sparcv9/ld.so.1") == 0)
166 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
168 return (svr4_same_1 (gdb
->so_original_name
, inferior
->so_original_name
));
171 static lm_info_svr4
*
172 lm_info_read (CORE_ADDR lm_addr
)
174 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
176 lm_info_svr4
*lm_info
;
177 struct cleanup
*back_to
;
179 lm
= (gdb_byte
*) xmalloc (lmo
->link_map_size
);
180 back_to
= make_cleanup (xfree
, lm
);
182 if (target_read_memory (lm_addr
, lm
, lmo
->link_map_size
) != 0)
184 warning (_("Error reading shared library list entry at %s"),
185 paddress (target_gdbarch (), lm_addr
)),
190 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
192 lm_info
= XCNEW (lm_info_svr4
);
193 lm_info
->lm_addr
= lm_addr
;
195 lm_info
->l_addr_inferior
= extract_typed_address (&lm
[lmo
->l_addr_offset
],
197 lm_info
->l_ld
= extract_typed_address (&lm
[lmo
->l_ld_offset
], ptr_type
);
198 lm_info
->l_next
= extract_typed_address (&lm
[lmo
->l_next_offset
],
200 lm_info
->l_prev
= extract_typed_address (&lm
[lmo
->l_prev_offset
],
202 lm_info
->l_name
= extract_typed_address (&lm
[lmo
->l_name_offset
],
206 do_cleanups (back_to
);
212 has_lm_dynamic_from_link_map (void)
214 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
216 return lmo
->l_ld_offset
>= 0;
220 lm_addr_check (const struct so_list
*so
, bfd
*abfd
)
222 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
226 struct bfd_section
*dyninfo_sect
;
227 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
;
229 l_addr
= li
->l_addr_inferior
;
231 if (! abfd
|| ! has_lm_dynamic_from_link_map ())
234 l_dynaddr
= li
->l_ld
;
236 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
237 if (dyninfo_sect
== NULL
)
240 dynaddr
= bfd_section_vma (abfd
, dyninfo_sect
);
242 if (dynaddr
+ l_addr
!= l_dynaddr
)
244 CORE_ADDR align
= 0x1000;
245 CORE_ADDR minpagesize
= align
;
247 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
249 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
250 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
255 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
256 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
257 align
= phdr
[i
].p_align
;
259 minpagesize
= get_elf_backend_data (abfd
)->minpagesize
;
262 /* Turn it into a mask. */
265 /* If the changes match the alignment requirements, we
266 assume we're using a core file that was generated by the
267 same binary, just prelinked with a different base offset.
268 If it doesn't match, we may have a different binary, the
269 same binary with the dynamic table loaded at an unrelated
270 location, or anything, really. To avoid regressions,
271 don't adjust the base offset in the latter case, although
272 odds are that, if things really changed, debugging won't
275 One could expect more the condition
276 ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
277 but the one below is relaxed for PPC. The PPC kernel supports
278 either 4k or 64k page sizes. To be prepared for 64k pages,
279 PPC ELF files are built using an alignment requirement of 64k.
280 However, when running on a kernel supporting 4k pages, the memory
281 mapping of the library may not actually happen on a 64k boundary!
283 (In the usual case where (l_addr & align) == 0, this check is
284 equivalent to the possibly expected check above.)
286 Even on PPC it must be zero-aligned at least for MINPAGESIZE. */
288 l_addr
= l_dynaddr
- dynaddr
;
290 if ((l_addr
& (minpagesize
- 1)) == 0
291 && (l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
294 printf_unfiltered (_("Using PIC (Position Independent Code) "
295 "prelink displacement %s for \"%s\".\n"),
296 paddress (target_gdbarch (), l_addr
),
301 /* There is no way to verify the library file matches. prelink
302 can during prelinking of an unprelinked file (or unprelinking
303 of a prelinked file) shift the DYNAMIC segment by arbitrary
304 offset without any page size alignment. There is no way to
305 find out the ELF header and/or Program Headers for a limited
306 verification if it they match. One could do a verification
307 of the DYNAMIC segment. Still the found address is the best
308 one GDB could find. */
310 warning (_(".dynamic section for \"%s\" "
311 "is not at the expected address "
312 "(wrong library or version mismatch?)"), so
->so_name
);
324 /* Per pspace SVR4 specific data. */
328 CORE_ADDR debug_base
; /* Base of dynamic linker structures. */
330 /* Validity flag for debug_loader_offset. */
331 int debug_loader_offset_p
;
333 /* Load address for the dynamic linker, inferred. */
334 CORE_ADDR debug_loader_offset
;
336 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
337 char *debug_loader_name
;
339 /* Load map address for the main executable. */
340 CORE_ADDR main_lm_addr
;
342 CORE_ADDR interp_text_sect_low
;
343 CORE_ADDR interp_text_sect_high
;
344 CORE_ADDR interp_plt_sect_low
;
345 CORE_ADDR interp_plt_sect_high
;
347 /* Nonzero if the list of objects was last obtained from the target
348 via qXfer:libraries-svr4:read. */
351 /* Table of struct probe_and_action instances, used by the
352 probes-based interface to map breakpoint addresses to probes
353 and their associated actions. Lookup is performed using
354 probe_and_action->probe->address. */
357 /* List of objects loaded into the inferior, used by the probes-
359 struct so_list
*solib_list
;
362 /* Per-program-space data key. */
363 static const struct program_space_data
*solib_svr4_pspace_data
;
365 /* Free the probes table. */
368 free_probes_table (struct svr4_info
*info
)
370 if (info
->probes_table
== NULL
)
373 htab_delete (info
->probes_table
);
374 info
->probes_table
= NULL
;
377 /* Free the solib list. */
380 free_solib_list (struct svr4_info
*info
)
382 svr4_free_library_list (&info
->solib_list
);
383 info
->solib_list
= NULL
;
387 svr4_pspace_data_cleanup (struct program_space
*pspace
, void *arg
)
389 struct svr4_info
*info
= (struct svr4_info
*) arg
;
391 free_probes_table (info
);
392 free_solib_list (info
);
397 /* Get the current svr4 data. If none is found yet, add it now. This
398 function always returns a valid object. */
400 static struct svr4_info
*
403 struct svr4_info
*info
;
405 info
= (struct svr4_info
*) program_space_data (current_program_space
,
406 solib_svr4_pspace_data
);
410 info
= XCNEW (struct svr4_info
);
411 set_program_space_data (current_program_space
, solib_svr4_pspace_data
, info
);
415 /* Local function prototypes */
417 static int match_main (const char *);
419 /* Read program header TYPE from inferior memory. The header is found
420 by scanning the OS auxillary vector.
422 If TYPE == -1, return the program headers instead of the contents of
425 Return a pointer to allocated memory holding the program header contents,
426 or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the
427 size of those contents is returned to P_SECT_SIZE. Likewise, the target
428 architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE and
429 the base address of the section is returned in BASE_ADDR. */
432 read_program_header (int type
, int *p_sect_size
, int *p_arch_size
,
433 CORE_ADDR
*base_addr
)
435 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
436 CORE_ADDR at_phdr
, at_phent
, at_phnum
, pt_phdr
= 0;
437 int arch_size
, sect_size
;
442 /* Get required auxv elements from target. */
443 if (target_auxv_search (¤t_target
, AT_PHDR
, &at_phdr
) <= 0)
445 if (target_auxv_search (¤t_target
, AT_PHENT
, &at_phent
) <= 0)
447 if (target_auxv_search (¤t_target
, AT_PHNUM
, &at_phnum
) <= 0)
449 if (!at_phdr
|| !at_phnum
)
452 /* Determine ELF architecture type. */
453 if (at_phent
== sizeof (Elf32_External_Phdr
))
455 else if (at_phent
== sizeof (Elf64_External_Phdr
))
460 /* Find the requested segment. */
464 sect_size
= at_phent
* at_phnum
;
466 else if (arch_size
== 32)
468 Elf32_External_Phdr phdr
;
471 /* Search for requested PHDR. */
472 for (i
= 0; i
< at_phnum
; i
++)
476 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
477 (gdb_byte
*)&phdr
, sizeof (phdr
)))
480 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
483 if (p_type
== PT_PHDR
)
486 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
497 /* Retrieve address and size. */
498 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
500 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
505 Elf64_External_Phdr phdr
;
508 /* Search for requested PHDR. */
509 for (i
= 0; i
< at_phnum
; i
++)
513 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
514 (gdb_byte
*)&phdr
, sizeof (phdr
)))
517 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
520 if (p_type
== PT_PHDR
)
523 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
534 /* Retrieve address and size. */
535 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
537 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
541 /* PT_PHDR is optional, but we really need it
542 for PIE to make this work in general. */
546 /* at_phdr is real address in memory. pt_phdr is what pheader says it is.
547 Relocation offset is the difference between the two. */
548 sect_addr
= sect_addr
+ (at_phdr
- pt_phdr
);
551 /* Read in requested program header. */
552 buf
= (gdb_byte
*) xmalloc (sect_size
);
553 if (target_read_memory (sect_addr
, buf
, sect_size
))
560 *p_arch_size
= arch_size
;
562 *p_sect_size
= sect_size
;
564 *base_addr
= sect_addr
;
570 /* Return program interpreter string. */
572 find_program_interpreter (void)
574 gdb_byte
*buf
= NULL
;
576 /* If we have an exec_bfd, use its section table. */
578 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
580 struct bfd_section
*interp_sect
;
582 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
583 if (interp_sect
!= NULL
)
585 int sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
587 buf
= (gdb_byte
*) xmalloc (sect_size
);
588 bfd_get_section_contents (exec_bfd
, interp_sect
, buf
, 0, sect_size
);
592 /* If we didn't find it, use the target auxillary vector. */
594 buf
= read_program_header (PT_INTERP
, NULL
, NULL
, NULL
);
600 /* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is
601 found, 1 is returned and the corresponding PTR is set. */
604 scan_dyntag (const int desired_dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
,
607 int arch_size
, step
, sect_size
;
609 CORE_ADDR dyn_ptr
, dyn_addr
;
610 gdb_byte
*bufend
, *bufstart
, *buf
;
611 Elf32_External_Dyn
*x_dynp_32
;
612 Elf64_External_Dyn
*x_dynp_64
;
613 struct bfd_section
*sect
;
614 struct target_section
*target_section
;
619 if (bfd_get_flavour (abfd
) != bfd_target_elf_flavour
)
622 arch_size
= bfd_get_arch_size (abfd
);
626 /* Find the start address of the .dynamic section. */
627 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
631 for (target_section
= current_target_sections
->sections
;
632 target_section
< current_target_sections
->sections_end
;
634 if (sect
== target_section
->the_bfd_section
)
636 if (target_section
< current_target_sections
->sections_end
)
637 dyn_addr
= target_section
->addr
;
640 /* ABFD may come from OBJFILE acting only as a symbol file without being
641 loaded into the target (see add_symbol_file_command). This case is
642 such fallback to the file VMA address without the possibility of
643 having the section relocated to its actual in-memory address. */
645 dyn_addr
= bfd_section_vma (abfd
, sect
);
648 /* Read in .dynamic from the BFD. We will get the actual value
649 from memory later. */
650 sect_size
= bfd_section_size (abfd
, sect
);
651 buf
= bufstart
= (gdb_byte
*) alloca (sect_size
);
652 if (!bfd_get_section_contents (abfd
, sect
,
656 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
657 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
658 : sizeof (Elf64_External_Dyn
);
659 for (bufend
= buf
+ sect_size
;
665 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
666 current_dyntag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
667 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
671 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
672 current_dyntag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
673 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
675 if (current_dyntag
== DT_NULL
)
677 if (current_dyntag
== desired_dyntag
)
679 /* If requested, try to read the runtime value of this .dynamic
683 struct type
*ptr_type
;
685 CORE_ADDR ptr_addr_1
;
687 ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
688 ptr_addr_1
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
689 if (target_read_memory (ptr_addr_1
, ptr_buf
, arch_size
/ 8) == 0)
690 dyn_ptr
= extract_typed_address (ptr_buf
, ptr_type
);
693 *ptr_addr
= dyn_addr
+ (buf
- bufstart
);
702 /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable,
703 found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1
704 is returned and the corresponding PTR is set. */
707 scan_dyntag_auxv (const int desired_dyntag
, CORE_ADDR
*ptr
,
710 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
711 int sect_size
, arch_size
, step
;
715 gdb_byte
*bufend
, *bufstart
, *buf
;
717 /* Read in .dynamic section. */
718 buf
= bufstart
= read_program_header (PT_DYNAMIC
, §_size
, &arch_size
,
723 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
724 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
725 : sizeof (Elf64_External_Dyn
);
726 for (bufend
= buf
+ sect_size
;
732 Elf32_External_Dyn
*dynp
= (Elf32_External_Dyn
*) buf
;
734 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
736 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
741 Elf64_External_Dyn
*dynp
= (Elf64_External_Dyn
*) buf
;
743 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
745 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
748 if (current_dyntag
== DT_NULL
)
751 if (current_dyntag
== desired_dyntag
)
757 *ptr_addr
= base_addr
+ buf
- bufstart
;
768 /* Locate the base address of dynamic linker structs for SVR4 elf
771 For SVR4 elf targets the address of the dynamic linker's runtime
772 structure is contained within the dynamic info section in the
773 executable file. The dynamic section is also mapped into the
774 inferior address space. Because the runtime loader fills in the
775 real address before starting the inferior, we have to read in the
776 dynamic info section from the inferior address space.
777 If there are any errors while trying to find the address, we
778 silently return 0, otherwise the found address is returned. */
781 elf_locate_base (void)
783 struct bound_minimal_symbol msymbol
;
784 CORE_ADDR dyn_ptr
, dyn_ptr_addr
;
786 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
787 instead of DT_DEBUG, although they sometimes contain an unused
789 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
, NULL
)
790 || scan_dyntag_auxv (DT_MIPS_RLD_MAP
, &dyn_ptr
, NULL
))
792 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
794 int pbuf_size
= TYPE_LENGTH (ptr_type
);
796 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
797 /* DT_MIPS_RLD_MAP contains a pointer to the address
798 of the dynamic link structure. */
799 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
801 return extract_typed_address (pbuf
, ptr_type
);
804 /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form
805 because of needing to support PIE. DT_MIPS_RLD_MAP will also exist
807 if (scan_dyntag (DT_MIPS_RLD_MAP_REL
, exec_bfd
, &dyn_ptr
, &dyn_ptr_addr
)
808 || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL
, &dyn_ptr
, &dyn_ptr_addr
))
810 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
812 int pbuf_size
= TYPE_LENGTH (ptr_type
);
814 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
815 /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the
816 DT slot to the address of the dynamic link structure. */
817 if (target_read_memory (dyn_ptr
+ dyn_ptr_addr
, pbuf
, pbuf_size
))
819 return extract_typed_address (pbuf
, ptr_type
);
823 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
, NULL
)
824 || scan_dyntag_auxv (DT_DEBUG
, &dyn_ptr
, NULL
))
827 /* This may be a static executable. Look for the symbol
828 conventionally named _r_debug, as a last resort. */
829 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
830 if (msymbol
.minsym
!= NULL
)
831 return BMSYMBOL_VALUE_ADDRESS (msymbol
);
833 /* DT_DEBUG entry not found. */
837 /* Locate the base address of dynamic linker structs.
839 For both the SunOS and SVR4 shared library implementations, if the
840 inferior executable has been linked dynamically, there is a single
841 address somewhere in the inferior's data space which is the key to
842 locating all of the dynamic linker's runtime structures. This
843 address is the value of the debug base symbol. The job of this
844 function is to find and return that address, or to return 0 if there
845 is no such address (the executable is statically linked for example).
847 For SunOS, the job is almost trivial, since the dynamic linker and
848 all of it's structures are statically linked to the executable at
849 link time. Thus the symbol for the address we are looking for has
850 already been added to the minimal symbol table for the executable's
851 objfile at the time the symbol file's symbols were read, and all we
852 have to do is look it up there. Note that we explicitly do NOT want
853 to find the copies in the shared library.
855 The SVR4 version is a bit more complicated because the address
856 is contained somewhere in the dynamic info section. We have to go
857 to a lot more work to discover the address of the debug base symbol.
858 Because of this complexity, we cache the value we find and return that
859 value on subsequent invocations. Note there is no copy in the
860 executable symbol tables. */
863 locate_base (struct svr4_info
*info
)
865 /* Check to see if we have a currently valid address, and if so, avoid
866 doing all this work again and just return the cached address. If
867 we have no cached address, try to locate it in the dynamic info
868 section for ELF executables. There's no point in doing any of this
869 though if we don't have some link map offsets to work with. */
871 if (info
->debug_base
== 0 && svr4_have_link_map_offsets ())
872 info
->debug_base
= elf_locate_base ();
873 return info
->debug_base
;
876 /* Find the first element in the inferior's dynamic link map, and
877 return its address in the inferior. Return zero if the address
878 could not be determined.
880 FIXME: Perhaps we should validate the info somehow, perhaps by
881 checking r_version for a known version number, or r_state for
885 solib_svr4_r_map (struct svr4_info
*info
)
887 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
888 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
893 addr
= read_memory_typed_address (info
->debug_base
+ lmo
->r_map_offset
,
896 CATCH (ex
, RETURN_MASK_ERROR
)
898 exception_print (gdb_stderr
, ex
);
905 /* Find r_brk from the inferior's debug base. */
908 solib_svr4_r_brk (struct svr4_info
*info
)
910 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
911 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
913 return read_memory_typed_address (info
->debug_base
+ lmo
->r_brk_offset
,
917 /* Find the link map for the dynamic linker (if it is not in the
918 normal list of loaded shared objects). */
921 solib_svr4_r_ldsomap (struct svr4_info
*info
)
923 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
924 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
925 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
926 ULONGEST version
= 0;
930 /* Check version, and return zero if `struct r_debug' doesn't have
931 the r_ldsomap member. */
933 = read_memory_unsigned_integer (info
->debug_base
+ lmo
->r_version_offset
,
934 lmo
->r_version_size
, byte_order
);
936 CATCH (ex
, RETURN_MASK_ERROR
)
938 exception_print (gdb_stderr
, ex
);
942 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
945 return read_memory_typed_address (info
->debug_base
+ lmo
->r_ldsomap_offset
,
949 /* On Solaris systems with some versions of the dynamic linker,
950 ld.so's l_name pointer points to the SONAME in the string table
951 rather than into writable memory. So that GDB can find shared
952 libraries when loading a core file generated by gcore, ensure that
953 memory areas containing the l_name string are saved in the core
957 svr4_keep_data_in_core (CORE_ADDR vaddr
, unsigned long size
)
959 struct svr4_info
*info
;
961 struct so_list
*newobj
;
962 struct cleanup
*old_chain
;
965 info
= get_svr4_info ();
967 info
->debug_base
= 0;
969 if (!info
->debug_base
)
972 ldsomap
= solib_svr4_r_ldsomap (info
);
976 newobj
= XCNEW (struct so_list
);
977 old_chain
= make_cleanup (xfree
, newobj
);
978 lm_info_svr4
*li
= lm_info_read (ldsomap
);
979 newobj
->lm_info
= li
;
980 make_cleanup (xfree
, newobj
->lm_info
);
981 name_lm
= li
!= NULL
? li
->l_name
: 0;
982 do_cleanups (old_chain
);
984 return (name_lm
>= vaddr
&& name_lm
< vaddr
+ size
);
987 /* Implement the "open_symbol_file_object" target_so_ops method.
989 If no open symbol file, attempt to locate and open the main symbol
990 file. On SVR4 systems, this is the first link map entry. If its
991 name is here, we can open it. Useful when attaching to a process
992 without first loading its symbol file. */
995 open_symbol_file_object (void *from_ttyp
)
997 CORE_ADDR lm
, l_name
;
1000 int from_tty
= *(int *)from_ttyp
;
1001 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
1002 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
1003 int l_name_size
= TYPE_LENGTH (ptr_type
);
1004 gdb_byte
*l_name_buf
= (gdb_byte
*) xmalloc (l_name_size
);
1005 struct cleanup
*cleanups
= make_cleanup (xfree
, l_name_buf
);
1006 struct svr4_info
*info
= get_svr4_info ();
1007 symfile_add_flags add_flags
= 0;
1010 add_flags
|= SYMFILE_VERBOSE
;
1012 if (symfile_objfile
)
1013 if (!query (_("Attempt to reload symbols from process? ")))
1015 do_cleanups (cleanups
);
1019 /* Always locate the debug struct, in case it has moved. */
1020 info
->debug_base
= 0;
1021 if (locate_base (info
) == 0)
1023 do_cleanups (cleanups
);
1024 return 0; /* failed somehow... */
1027 /* First link map member should be the executable. */
1028 lm
= solib_svr4_r_map (info
);
1031 do_cleanups (cleanups
);
1032 return 0; /* failed somehow... */
1035 /* Read address of name from target memory to GDB. */
1036 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
1038 /* Convert the address to host format. */
1039 l_name
= extract_typed_address (l_name_buf
, ptr_type
);
1043 do_cleanups (cleanups
);
1044 return 0; /* No filename. */
1047 /* Now fetch the filename from target memory. */
1048 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
1049 make_cleanup (xfree
, filename
);
1053 warning (_("failed to read exec filename from attached file: %s"),
1054 safe_strerror (errcode
));
1055 do_cleanups (cleanups
);
1059 /* Have a pathname: read the symbol file. */
1060 symbol_file_add_main (filename
, add_flags
);
1062 do_cleanups (cleanups
);
1066 /* Data exchange structure for the XML parser as returned by
1067 svr4_current_sos_via_xfer_libraries. */
1069 struct svr4_library_list
1071 struct so_list
*head
, **tailp
;
1073 /* Inferior address of struct link_map used for the main executable. It is
1074 NULL if not known. */
1078 /* Implementation for target_so_ops.free_so. */
1081 svr4_free_so (struct so_list
*so
)
1083 xfree (so
->lm_info
);
1086 /* Implement target_so_ops.clear_so. */
1089 svr4_clear_so (struct so_list
*so
)
1091 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1097 /* Free so_list built so far (called via cleanup). */
1100 svr4_free_library_list (void *p_list
)
1102 struct so_list
*list
= *(struct so_list
**) p_list
;
1104 while (list
!= NULL
)
1106 struct so_list
*next
= list
->next
;
1113 /* Copy library list. */
1115 static struct so_list
*
1116 svr4_copy_library_list (struct so_list
*src
)
1118 struct so_list
*dst
= NULL
;
1119 struct so_list
**link
= &dst
;
1123 struct so_list
*newobj
;
1125 newobj
= XNEW (struct so_list
);
1126 memcpy (newobj
, src
, sizeof (struct so_list
));
1128 newobj
->lm_info
= XNEW (lm_info_svr4
);
1129 memcpy (newobj
->lm_info
, src
->lm_info
, sizeof (lm_info_svr4
));
1131 newobj
->next
= NULL
;
1133 link
= &newobj
->next
;
1141 #ifdef HAVE_LIBEXPAT
1143 #include "xml-support.h"
1145 /* Handle the start of a <library> element. Note: new elements are added
1146 at the tail of the list, keeping the list in order. */
1149 library_list_start_library (struct gdb_xml_parser
*parser
,
1150 const struct gdb_xml_element
*element
,
1151 void *user_data
, VEC(gdb_xml_value_s
) *attributes
)
1153 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1155 = (const char *) xml_find_attribute (attributes
, "name")->value
;
1157 = (ULONGEST
*) xml_find_attribute (attributes
, "lm")->value
;
1159 = (ULONGEST
*) xml_find_attribute (attributes
, "l_addr")->value
;
1161 = (ULONGEST
*) xml_find_attribute (attributes
, "l_ld")->value
;
1162 struct so_list
*new_elem
;
1164 new_elem
= XCNEW (struct so_list
);
1165 lm_info_svr4
*li
= XCNEW (lm_info_svr4
);
1166 new_elem
->lm_info
= li
;
1168 li
->l_addr_inferior
= *l_addrp
;
1171 strncpy (new_elem
->so_name
, name
, sizeof (new_elem
->so_name
) - 1);
1172 new_elem
->so_name
[sizeof (new_elem
->so_name
) - 1] = 0;
1173 strcpy (new_elem
->so_original_name
, new_elem
->so_name
);
1175 *list
->tailp
= new_elem
;
1176 list
->tailp
= &new_elem
->next
;
1179 /* Handle the start of a <library-list-svr4> element. */
1182 svr4_library_list_start_list (struct gdb_xml_parser
*parser
,
1183 const struct gdb_xml_element
*element
,
1184 void *user_data
, VEC(gdb_xml_value_s
) *attributes
)
1186 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1188 = (const char *) xml_find_attribute (attributes
, "version")->value
;
1189 struct gdb_xml_value
*main_lm
= xml_find_attribute (attributes
, "main-lm");
1191 if (strcmp (version
, "1.0") != 0)
1192 gdb_xml_error (parser
,
1193 _("SVR4 Library list has unsupported version \"%s\""),
1197 list
->main_lm
= *(ULONGEST
*) main_lm
->value
;
1200 /* The allowed elements and attributes for an XML library list.
1201 The root element is a <library-list>. */
1203 static const struct gdb_xml_attribute svr4_library_attributes
[] =
1205 { "name", GDB_XML_AF_NONE
, NULL
, NULL
},
1206 { "lm", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1207 { "l_addr", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1208 { "l_ld", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1209 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1212 static const struct gdb_xml_element svr4_library_list_children
[] =
1215 "library", svr4_library_attributes
, NULL
,
1216 GDB_XML_EF_REPEATABLE
| GDB_XML_EF_OPTIONAL
,
1217 library_list_start_library
, NULL
1219 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1222 static const struct gdb_xml_attribute svr4_library_list_attributes
[] =
1224 { "version", GDB_XML_AF_NONE
, NULL
, NULL
},
1225 { "main-lm", GDB_XML_AF_OPTIONAL
, gdb_xml_parse_attr_ulongest
, NULL
},
1226 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1229 static const struct gdb_xml_element svr4_library_list_elements
[] =
1231 { "library-list-svr4", svr4_library_list_attributes
, svr4_library_list_children
,
1232 GDB_XML_EF_NONE
, svr4_library_list_start_list
, NULL
},
1233 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1236 /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if
1238 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1239 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1240 empty, caller is responsible for freeing all its entries. */
1243 svr4_parse_libraries (const char *document
, struct svr4_library_list
*list
)
1245 struct cleanup
*back_to
= make_cleanup (svr4_free_library_list
,
1248 memset (list
, 0, sizeof (*list
));
1249 list
->tailp
= &list
->head
;
1250 if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd",
1251 svr4_library_list_elements
, document
, list
) == 0)
1253 /* Parsed successfully, keep the result. */
1254 discard_cleanups (back_to
);
1258 do_cleanups (back_to
);
1262 /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet.
1264 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1265 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1266 empty, caller is responsible for freeing all its entries.
1268 Note that ANNEX must be NULL if the remote does not explicitly allow
1269 qXfer:libraries-svr4:read packets with non-empty annexes. Support for
1270 this can be checked using target_augmented_libraries_svr4_read (). */
1273 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1276 char *svr4_library_document
;
1278 struct cleanup
*back_to
;
1280 gdb_assert (annex
== NULL
|| target_augmented_libraries_svr4_read ());
1282 /* Fetch the list of shared libraries. */
1283 svr4_library_document
= target_read_stralloc (¤t_target
,
1284 TARGET_OBJECT_LIBRARIES_SVR4
,
1286 if (svr4_library_document
== NULL
)
1289 back_to
= make_cleanup (xfree
, svr4_library_document
);
1290 result
= svr4_parse_libraries (svr4_library_document
, list
);
1291 do_cleanups (back_to
);
1299 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1307 /* If no shared library information is available from the dynamic
1308 linker, build a fallback list from other sources. */
1310 static struct so_list
*
1311 svr4_default_sos (void)
1313 struct svr4_info
*info
= get_svr4_info ();
1314 struct so_list
*newobj
;
1316 if (!info
->debug_loader_offset_p
)
1319 newobj
= XCNEW (struct so_list
);
1320 lm_info_svr4
*li
= XCNEW (lm_info_svr4
);
1321 newobj
->lm_info
= li
;
1323 /* Nothing will ever check the other fields if we set l_addr_p. */
1324 li
->l_addr
= info
->debug_loader_offset
;
1327 strncpy (newobj
->so_name
, info
->debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
1328 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1329 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1334 /* Read the whole inferior libraries chain starting at address LM.
1335 Expect the first entry in the chain's previous entry to be PREV_LM.
1336 Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the
1337 first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according
1338 to it. Returns nonzero upon success. If zero is returned the
1339 entries stored to LINK_PTR_PTR are still valid although they may
1340 represent only part of the inferior library list. */
1343 svr4_read_so_list (CORE_ADDR lm
, CORE_ADDR prev_lm
,
1344 struct so_list
***link_ptr_ptr
, int ignore_first
)
1346 CORE_ADDR first_l_name
= 0;
1349 for (; lm
!= 0; prev_lm
= lm
, lm
= next_lm
)
1351 struct so_list
*newobj
;
1352 struct cleanup
*old_chain
;
1356 newobj
= XCNEW (struct so_list
);
1357 old_chain
= make_cleanup_free_so (newobj
);
1359 lm_info_svr4
*li
= lm_info_read (lm
);
1360 newobj
->lm_info
= li
;
1363 do_cleanups (old_chain
);
1367 next_lm
= li
->l_next
;
1369 if (li
->l_prev
!= prev_lm
)
1371 warning (_("Corrupted shared library list: %s != %s"),
1372 paddress (target_gdbarch (), prev_lm
),
1373 paddress (target_gdbarch (), li
->l_prev
));
1374 do_cleanups (old_chain
);
1378 /* For SVR4 versions, the first entry in the link map is for the
1379 inferior executable, so we must ignore it. For some versions of
1380 SVR4, it has no name. For others (Solaris 2.3 for example), it
1381 does have a name, so we can no longer use a missing name to
1382 decide when to ignore it. */
1383 if (ignore_first
&& li
->l_prev
== 0)
1385 struct svr4_info
*info
= get_svr4_info ();
1387 first_l_name
= li
->l_name
;
1388 info
->main_lm_addr
= li
->lm_addr
;
1389 do_cleanups (old_chain
);
1393 /* Extract this shared object's name. */
1394 target_read_string (li
->l_name
, &buffer
, SO_NAME_MAX_PATH_SIZE
- 1,
1398 /* If this entry's l_name address matches that of the
1399 inferior executable, then this is not a normal shared
1400 object, but (most likely) a vDSO. In this case, silently
1401 skip it; otherwise emit a warning. */
1402 if (first_l_name
== 0 || li
->l_name
!= first_l_name
)
1403 warning (_("Can't read pathname for load map: %s."),
1404 safe_strerror (errcode
));
1405 do_cleanups (old_chain
);
1409 strncpy (newobj
->so_name
, buffer
, SO_NAME_MAX_PATH_SIZE
- 1);
1410 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1411 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1414 /* If this entry has no name, or its name matches the name
1415 for the main executable, don't include it in the list. */
1416 if (! newobj
->so_name
[0] || match_main (newobj
->so_name
))
1418 do_cleanups (old_chain
);
1422 discard_cleanups (old_chain
);
1424 **link_ptr_ptr
= newobj
;
1425 *link_ptr_ptr
= &newobj
->next
;
1431 /* Read the full list of currently loaded shared objects directly
1432 from the inferior, without referring to any libraries read and
1433 stored by the probes interface. Handle special cases relating
1434 to the first elements of the list. */
1436 static struct so_list
*
1437 svr4_current_sos_direct (struct svr4_info
*info
)
1440 struct so_list
*head
= NULL
;
1441 struct so_list
**link_ptr
= &head
;
1442 struct cleanup
*back_to
;
1444 struct svr4_library_list library_list
;
1446 /* Fall back to manual examination of the target if the packet is not
1447 supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp
1448 tests a case where gdbserver cannot find the shared libraries list while
1449 GDB itself is able to find it via SYMFILE_OBJFILE.
1451 Unfortunately statically linked inferiors will also fall back through this
1452 suboptimal code path. */
1454 info
->using_xfer
= svr4_current_sos_via_xfer_libraries (&library_list
,
1456 if (info
->using_xfer
)
1458 if (library_list
.main_lm
)
1459 info
->main_lm_addr
= library_list
.main_lm
;
1461 return library_list
.head
? library_list
.head
: svr4_default_sos ();
1464 /* Always locate the debug struct, in case it has moved. */
1465 info
->debug_base
= 0;
1468 /* If we can't find the dynamic linker's base structure, this
1469 must not be a dynamically linked executable. Hmm. */
1470 if (! info
->debug_base
)
1471 return svr4_default_sos ();
1473 /* Assume that everything is a library if the dynamic loader was loaded
1474 late by a static executable. */
1475 if (exec_bfd
&& bfd_get_section_by_name (exec_bfd
, ".dynamic") == NULL
)
1480 back_to
= make_cleanup (svr4_free_library_list
, &head
);
1482 /* Walk the inferior's link map list, and build our list of
1483 `struct so_list' nodes. */
1484 lm
= solib_svr4_r_map (info
);
1486 svr4_read_so_list (lm
, 0, &link_ptr
, ignore_first
);
1488 /* On Solaris, the dynamic linker is not in the normal list of
1489 shared objects, so make sure we pick it up too. Having
1490 symbol information for the dynamic linker is quite crucial
1491 for skipping dynamic linker resolver code. */
1492 lm
= solib_svr4_r_ldsomap (info
);
1494 svr4_read_so_list (lm
, 0, &link_ptr
, 0);
1496 discard_cleanups (back_to
);
1499 return svr4_default_sos ();
1504 /* Implement the main part of the "current_sos" target_so_ops
1507 static struct so_list
*
1508 svr4_current_sos_1 (void)
1510 struct svr4_info
*info
= get_svr4_info ();
1512 /* If the solib list has been read and stored by the probes
1513 interface then we return a copy of the stored list. */
1514 if (info
->solib_list
!= NULL
)
1515 return svr4_copy_library_list (info
->solib_list
);
1517 /* Otherwise obtain the solib list directly from the inferior. */
1518 return svr4_current_sos_direct (info
);
1521 /* Implement the "current_sos" target_so_ops method. */
1523 static struct so_list
*
1524 svr4_current_sos (void)
1526 struct so_list
*so_head
= svr4_current_sos_1 ();
1527 struct mem_range vsyscall_range
;
1529 /* Filter out the vDSO module, if present. Its symbol file would
1530 not be found on disk. The vDSO/vsyscall's OBJFILE is instead
1531 managed by symfile-mem.c:add_vsyscall_page. */
1532 if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range
)
1533 && vsyscall_range
.length
!= 0)
1535 struct so_list
**sop
;
1538 while (*sop
!= NULL
)
1540 struct so_list
*so
= *sop
;
1542 /* We can't simply match the vDSO by starting address alone,
1543 because lm_info->l_addr_inferior (and also l_addr) do not
1544 necessarily represent the real starting address of the
1545 ELF if the vDSO's ELF itself is "prelinked". The l_ld
1546 field (the ".dynamic" section of the shared object)
1547 always points at the absolute/resolved address though.
1548 So check whether that address is inside the vDSO's
1551 E.g., on Linux 3.16 (x86_64) the vDSO is a regular
1552 0-based ELF, and we see:
1555 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000
1556 (gdb) p/x *_r_debug.r_map.l_next
1557 $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...}
1559 And on Linux 2.6.32 (x86_64) we see:
1562 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000
1563 (gdb) p/x *_r_debug.r_map.l_next
1564 $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... }
1566 Dumping that vDSO shows:
1568 (gdb) info proc mappings
1569 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso]
1570 (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000
1571 # readelf -Wa vdso.bin
1573 Entry point address: 0xffffffffff700700
1576 [Nr] Name Type Address Off Size
1577 [ 0] NULL 0000000000000000 000000 000000
1578 [ 1] .hash HASH ffffffffff700120 000120 000038
1579 [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8
1581 [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0
1584 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1586 if (address_in_mem_range (li
->l_ld
, &vsyscall_range
))
1600 /* Get the address of the link_map for a given OBJFILE. */
1603 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
1606 struct svr4_info
*info
= get_svr4_info ();
1608 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1609 if (info
->main_lm_addr
== 0)
1610 solib_add (NULL
, 0, auto_solib_add
);
1612 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1613 if (objfile
== symfile_objfile
)
1614 return info
->main_lm_addr
;
1616 /* The other link map addresses may be found by examining the list
1617 of shared libraries. */
1618 for (so
= master_so_list (); so
; so
= so
->next
)
1619 if (so
->objfile
== objfile
)
1621 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1630 /* On some systems, the only way to recognize the link map entry for
1631 the main executable file is by looking at its name. Return
1632 non-zero iff SONAME matches one of the known main executable names. */
1635 match_main (const char *soname
)
1637 const char * const *mainp
;
1639 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
1641 if (strcmp (soname
, *mainp
) == 0)
1648 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1649 SVR4 run time loader. */
1652 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
1654 struct svr4_info
*info
= get_svr4_info ();
1656 return ((pc
>= info
->interp_text_sect_low
1657 && pc
< info
->interp_text_sect_high
)
1658 || (pc
>= info
->interp_plt_sect_low
1659 && pc
< info
->interp_plt_sect_high
)
1660 || in_plt_section (pc
)
1661 || in_gnu_ifunc_stub (pc
));
1664 /* Given an executable's ABFD and target, compute the entry-point
1668 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
1672 /* KevinB wrote ... for most targets, the address returned by
1673 bfd_get_start_address() is the entry point for the start
1674 function. But, for some targets, bfd_get_start_address() returns
1675 the address of a function descriptor from which the entry point
1676 address may be extracted. This address is extracted by
1677 gdbarch_convert_from_func_ptr_addr(). The method
1678 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1679 function for targets which don't use function descriptors. */
1680 addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
1681 bfd_get_start_address (abfd
),
1683 return gdbarch_addr_bits_remove (target_gdbarch (), addr
);
1686 /* A probe and its associated action. */
1688 struct probe_and_action
1691 struct probe
*probe
;
1693 /* The relocated address of the probe. */
1697 enum probe_action action
;
1700 /* Returns a hash code for the probe_and_action referenced by p. */
1703 hash_probe_and_action (const void *p
)
1705 const struct probe_and_action
*pa
= (const struct probe_and_action
*) p
;
1707 return (hashval_t
) pa
->address
;
1710 /* Returns non-zero if the probe_and_actions referenced by p1 and p2
1714 equal_probe_and_action (const void *p1
, const void *p2
)
1716 const struct probe_and_action
*pa1
= (const struct probe_and_action
*) p1
;
1717 const struct probe_and_action
*pa2
= (const struct probe_and_action
*) p2
;
1719 return pa1
->address
== pa2
->address
;
1722 /* Register a solib event probe and its associated action in the
1726 register_solib_event_probe (struct probe
*probe
, CORE_ADDR address
,
1727 enum probe_action action
)
1729 struct svr4_info
*info
= get_svr4_info ();
1730 struct probe_and_action lookup
, *pa
;
1733 /* Create the probes table, if necessary. */
1734 if (info
->probes_table
== NULL
)
1735 info
->probes_table
= htab_create_alloc (1, hash_probe_and_action
,
1736 equal_probe_and_action
,
1737 xfree
, xcalloc
, xfree
);
1739 lookup
.probe
= probe
;
1740 lookup
.address
= address
;
1741 slot
= htab_find_slot (info
->probes_table
, &lookup
, INSERT
);
1742 gdb_assert (*slot
== HTAB_EMPTY_ENTRY
);
1744 pa
= XCNEW (struct probe_and_action
);
1746 pa
->address
= address
;
1747 pa
->action
= action
;
1752 /* Get the solib event probe at the specified location, and the
1753 action associated with it. Returns NULL if no solib event probe
1756 static struct probe_and_action
*
1757 solib_event_probe_at (struct svr4_info
*info
, CORE_ADDR address
)
1759 struct probe_and_action lookup
;
1762 lookup
.address
= address
;
1763 slot
= htab_find_slot (info
->probes_table
, &lookup
, NO_INSERT
);
1768 return (struct probe_and_action
*) *slot
;
1771 /* Decide what action to take when the specified solib event probe is
1774 static enum probe_action
1775 solib_event_probe_action (struct probe_and_action
*pa
)
1777 enum probe_action action
;
1778 unsigned probe_argc
= 0;
1779 struct frame_info
*frame
= get_current_frame ();
1781 action
= pa
->action
;
1782 if (action
== DO_NOTHING
|| action
== PROBES_INTERFACE_FAILED
)
1785 gdb_assert (action
== FULL_RELOAD
|| action
== UPDATE_OR_RELOAD
);
1787 /* Check that an appropriate number of arguments has been supplied.
1789 arg0: Lmid_t lmid (mandatory)
1790 arg1: struct r_debug *debug_base (mandatory)
1791 arg2: struct link_map *new (optional, for incremental updates) */
1794 probe_argc
= get_probe_argument_count (pa
->probe
, frame
);
1796 CATCH (ex
, RETURN_MASK_ERROR
)
1798 exception_print (gdb_stderr
, ex
);
1803 /* If get_probe_argument_count throws an exception, probe_argc will
1804 be set to zero. However, if pa->probe does not have arguments,
1805 then get_probe_argument_count will succeed but probe_argc will
1806 also be zero. Both cases happen because of different things, but
1807 they are treated equally here: action will be set to
1808 PROBES_INTERFACE_FAILED. */
1809 if (probe_argc
== 2)
1810 action
= FULL_RELOAD
;
1811 else if (probe_argc
< 2)
1812 action
= PROBES_INTERFACE_FAILED
;
1817 /* Populate the shared object list by reading the entire list of
1818 shared objects from the inferior. Handle special cases relating
1819 to the first elements of the list. Returns nonzero on success. */
1822 solist_update_full (struct svr4_info
*info
)
1824 free_solib_list (info
);
1825 info
->solib_list
= svr4_current_sos_direct (info
);
1830 /* Update the shared object list starting from the link-map entry
1831 passed by the linker in the probe's third argument. Returns
1832 nonzero if the list was successfully updated, or zero to indicate
1836 solist_update_incremental (struct svr4_info
*info
, CORE_ADDR lm
)
1838 struct so_list
*tail
;
1841 /* svr4_current_sos_direct contains logic to handle a number of
1842 special cases relating to the first elements of the list. To
1843 avoid duplicating this logic we defer to solist_update_full
1844 if the list is empty. */
1845 if (info
->solib_list
== NULL
)
1848 /* Fall back to a full update if we are using a remote target
1849 that does not support incremental transfers. */
1850 if (info
->using_xfer
&& !target_augmented_libraries_svr4_read ())
1853 /* Walk to the end of the list. */
1854 for (tail
= info
->solib_list
; tail
->next
!= NULL
; tail
= tail
->next
)
1857 lm_info_svr4
*li
= (lm_info_svr4
*) tail
->lm_info
;
1858 prev_lm
= li
->lm_addr
;
1860 /* Read the new objects. */
1861 if (info
->using_xfer
)
1863 struct svr4_library_list library_list
;
1866 xsnprintf (annex
, sizeof (annex
), "start=%s;prev=%s",
1867 phex_nz (lm
, sizeof (lm
)),
1868 phex_nz (prev_lm
, sizeof (prev_lm
)));
1869 if (!svr4_current_sos_via_xfer_libraries (&library_list
, annex
))
1872 tail
->next
= library_list
.head
;
1876 struct so_list
**link
= &tail
->next
;
1878 /* IGNORE_FIRST may safely be set to zero here because the
1879 above check and deferral to solist_update_full ensures
1880 that this call to svr4_read_so_list will never see the
1882 if (!svr4_read_so_list (lm
, prev_lm
, &link
, 0))
1889 /* Disable the probes-based linker interface and revert to the
1890 original interface. We don't reset the breakpoints as the
1891 ones set up for the probes-based interface are adequate. */
1894 disable_probes_interface_cleanup (void *arg
)
1896 struct svr4_info
*info
= get_svr4_info ();
1898 warning (_("Probes-based dynamic linker interface failed.\n"
1899 "Reverting to original interface.\n"));
1901 free_probes_table (info
);
1902 free_solib_list (info
);
1905 /* Update the solib list as appropriate when using the
1906 probes-based linker interface. Do nothing if using the
1907 standard interface. */
1910 svr4_handle_solib_event (void)
1912 struct svr4_info
*info
= get_svr4_info ();
1913 struct probe_and_action
*pa
;
1914 enum probe_action action
;
1915 struct cleanup
*old_chain
, *usm_chain
;
1916 struct value
*val
= NULL
;
1917 CORE_ADDR pc
, debug_base
, lm
= 0;
1918 struct frame_info
*frame
= get_current_frame ();
1920 /* Do nothing if not using the probes interface. */
1921 if (info
->probes_table
== NULL
)
1924 /* If anything goes wrong we revert to the original linker
1926 old_chain
= make_cleanup (disable_probes_interface_cleanup
, NULL
);
1928 pc
= regcache_read_pc (get_current_regcache ());
1929 pa
= solib_event_probe_at (info
, pc
);
1932 do_cleanups (old_chain
);
1936 action
= solib_event_probe_action (pa
);
1937 if (action
== PROBES_INTERFACE_FAILED
)
1939 do_cleanups (old_chain
);
1943 if (action
== DO_NOTHING
)
1945 discard_cleanups (old_chain
);
1949 /* evaluate_probe_argument looks up symbols in the dynamic linker
1950 using find_pc_section. find_pc_section is accelerated by a cache
1951 called the section map. The section map is invalidated every
1952 time a shared library is loaded or unloaded, and if the inferior
1953 is generating a lot of shared library events then the section map
1954 will be updated every time svr4_handle_solib_event is called.
1955 We called find_pc_section in svr4_create_solib_event_breakpoints,
1956 so we can guarantee that the dynamic linker's sections are in the
1957 section map. We can therefore inhibit section map updates across
1958 these calls to evaluate_probe_argument and save a lot of time. */
1959 inhibit_section_map_updates (current_program_space
);
1960 usm_chain
= make_cleanup (resume_section_map_updates_cleanup
,
1961 current_program_space
);
1965 val
= evaluate_probe_argument (pa
->probe
, 1, frame
);
1967 CATCH (ex
, RETURN_MASK_ERROR
)
1969 exception_print (gdb_stderr
, ex
);
1976 do_cleanups (old_chain
);
1980 debug_base
= value_as_address (val
);
1981 if (debug_base
== 0)
1983 do_cleanups (old_chain
);
1987 /* Always locate the debug struct, in case it moved. */
1988 info
->debug_base
= 0;
1989 if (locate_base (info
) == 0)
1991 do_cleanups (old_chain
);
1995 /* GDB does not currently support libraries loaded via dlmopen
1996 into namespaces other than the initial one. We must ignore
1997 any namespace other than the initial namespace here until
1998 support for this is added to GDB. */
1999 if (debug_base
!= info
->debug_base
)
2000 action
= DO_NOTHING
;
2002 if (action
== UPDATE_OR_RELOAD
)
2006 val
= evaluate_probe_argument (pa
->probe
, 2, frame
);
2008 CATCH (ex
, RETURN_MASK_ERROR
)
2010 exception_print (gdb_stderr
, ex
);
2011 do_cleanups (old_chain
);
2017 lm
= value_as_address (val
);
2020 action
= FULL_RELOAD
;
2023 /* Resume section map updates. */
2024 do_cleanups (usm_chain
);
2026 if (action
== UPDATE_OR_RELOAD
)
2028 if (!solist_update_incremental (info
, lm
))
2029 action
= FULL_RELOAD
;
2032 if (action
== FULL_RELOAD
)
2034 if (!solist_update_full (info
))
2036 do_cleanups (old_chain
);
2041 discard_cleanups (old_chain
);
2044 /* Helper function for svr4_update_solib_event_breakpoints. */
2047 svr4_update_solib_event_breakpoint (struct breakpoint
*b
, void *arg
)
2049 struct bp_location
*loc
;
2051 if (b
->type
!= bp_shlib_event
)
2053 /* Continue iterating. */
2057 for (loc
= b
->loc
; loc
!= NULL
; loc
= loc
->next
)
2059 struct svr4_info
*info
;
2060 struct probe_and_action
*pa
;
2062 info
= ((struct svr4_info
*)
2063 program_space_data (loc
->pspace
, solib_svr4_pspace_data
));
2064 if (info
== NULL
|| info
->probes_table
== NULL
)
2067 pa
= solib_event_probe_at (info
, loc
->address
);
2071 if (pa
->action
== DO_NOTHING
)
2073 if (b
->enable_state
== bp_disabled
&& stop_on_solib_events
)
2074 enable_breakpoint (b
);
2075 else if (b
->enable_state
== bp_enabled
&& !stop_on_solib_events
)
2076 disable_breakpoint (b
);
2082 /* Continue iterating. */
2086 /* Enable or disable optional solib event breakpoints as appropriate.
2087 Called whenever stop_on_solib_events is changed. */
2090 svr4_update_solib_event_breakpoints (void)
2092 iterate_over_breakpoints (svr4_update_solib_event_breakpoint
, NULL
);
2095 /* Create and register solib event breakpoints. PROBES is an array
2096 of NUM_PROBES elements, each of which is vector of probes. A
2097 solib event breakpoint will be created and registered for each
2101 svr4_create_probe_breakpoints (struct gdbarch
*gdbarch
,
2102 VEC (probe_p
) **probes
,
2103 struct objfile
*objfile
)
2107 for (i
= 0; i
< NUM_PROBES
; i
++)
2109 enum probe_action action
= probe_info
[i
].action
;
2110 struct probe
*probe
;
2114 VEC_iterate (probe_p
, probes
[i
], ix
, probe
);
2117 CORE_ADDR address
= get_probe_address (probe
, objfile
);
2119 create_solib_event_breakpoint (gdbarch
, address
);
2120 register_solib_event_probe (probe
, address
, action
);
2124 svr4_update_solib_event_breakpoints ();
2127 /* Both the SunOS and the SVR4 dynamic linkers call a marker function
2128 before and after mapping and unmapping shared libraries. The sole
2129 purpose of this method is to allow debuggers to set a breakpoint so
2130 they can track these changes.
2132 Some versions of the glibc dynamic linker contain named probes
2133 to allow more fine grained stopping. Given the address of the
2134 original marker function, this function attempts to find these
2135 probes, and if found, sets breakpoints on those instead. If the
2136 probes aren't found, a single breakpoint is set on the original
2140 svr4_create_solib_event_breakpoints (struct gdbarch
*gdbarch
,
2143 struct obj_section
*os
;
2145 os
= find_pc_section (address
);
2150 for (with_prefix
= 0; with_prefix
<= 1; with_prefix
++)
2152 VEC (probe_p
) *probes
[NUM_PROBES
];
2153 int all_probes_found
= 1;
2154 int checked_can_use_probe_arguments
= 0;
2157 memset (probes
, 0, sizeof (probes
));
2158 for (i
= 0; i
< NUM_PROBES
; i
++)
2160 const char *name
= probe_info
[i
].name
;
2164 /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4
2165 shipped with an early version of the probes code in
2166 which the probes' names were prefixed with "rtld_"
2167 and the "map_failed" probe did not exist. The
2168 locations of the probes are otherwise the same, so
2169 we check for probes with prefixed names if probes
2170 with unprefixed names are not present. */
2173 xsnprintf (buf
, sizeof (buf
), "rtld_%s", name
);
2177 probes
[i
] = find_probes_in_objfile (os
->objfile
, "rtld", name
);
2179 /* The "map_failed" probe did not exist in early
2180 versions of the probes code in which the probes'
2181 names were prefixed with "rtld_". */
2182 if (strcmp (name
, "rtld_map_failed") == 0)
2185 if (VEC_empty (probe_p
, probes
[i
]))
2187 all_probes_found
= 0;
2191 /* Ensure probe arguments can be evaluated. */
2192 if (!checked_can_use_probe_arguments
)
2194 p
= VEC_index (probe_p
, probes
[i
], 0);
2195 if (!can_evaluate_probe_arguments (p
))
2197 all_probes_found
= 0;
2200 checked_can_use_probe_arguments
= 1;
2204 if (all_probes_found
)
2205 svr4_create_probe_breakpoints (gdbarch
, probes
, os
->objfile
);
2207 for (i
= 0; i
< NUM_PROBES
; i
++)
2208 VEC_free (probe_p
, probes
[i
]);
2210 if (all_probes_found
)
2215 create_solib_event_breakpoint (gdbarch
, address
);
2218 /* Helper function for gdb_bfd_lookup_symbol. */
2221 cmp_name_and_sec_flags (const asymbol
*sym
, const void *data
)
2223 return (strcmp (sym
->name
, (const char *) data
) == 0
2224 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0);
2226 /* Arrange for dynamic linker to hit breakpoint.
2228 Both the SunOS and the SVR4 dynamic linkers have, as part of their
2229 debugger interface, support for arranging for the inferior to hit
2230 a breakpoint after mapping in the shared libraries. This function
2231 enables that breakpoint.
2233 For SunOS, there is a special flag location (in_debugger) which we
2234 set to 1. When the dynamic linker sees this flag set, it will set
2235 a breakpoint at a location known only to itself, after saving the
2236 original contents of that place and the breakpoint address itself,
2237 in it's own internal structures. When we resume the inferior, it
2238 will eventually take a SIGTRAP when it runs into the breakpoint.
2239 We handle this (in a different place) by restoring the contents of
2240 the breakpointed location (which is only known after it stops),
2241 chasing around to locate the shared libraries that have been
2242 loaded, then resuming.
2244 For SVR4, the debugger interface structure contains a member (r_brk)
2245 which is statically initialized at the time the shared library is
2246 built, to the offset of a function (_r_debug_state) which is guaran-
2247 teed to be called once before mapping in a library, and again when
2248 the mapping is complete. At the time we are examining this member,
2249 it contains only the unrelocated offset of the function, so we have
2250 to do our own relocation. Later, when the dynamic linker actually
2251 runs, it relocates r_brk to be the actual address of _r_debug_state().
2253 The debugger interface structure also contains an enumeration which
2254 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
2255 depending upon whether or not the library is being mapped or unmapped,
2256 and then set to RT_CONSISTENT after the library is mapped/unmapped. */
2259 enable_break (struct svr4_info
*info
, int from_tty
)
2261 struct bound_minimal_symbol msymbol
;
2262 const char * const *bkpt_namep
;
2263 asection
*interp_sect
;
2267 info
->interp_text_sect_low
= info
->interp_text_sect_high
= 0;
2268 info
->interp_plt_sect_low
= info
->interp_plt_sect_high
= 0;
2270 /* If we already have a shared library list in the target, and
2271 r_debug contains r_brk, set the breakpoint there - this should
2272 mean r_brk has already been relocated. Assume the dynamic linker
2273 is the object containing r_brk. */
2275 solib_add (NULL
, from_tty
, auto_solib_add
);
2277 if (info
->debug_base
&& solib_svr4_r_map (info
) != 0)
2278 sym_addr
= solib_svr4_r_brk (info
);
2282 struct obj_section
*os
;
2284 sym_addr
= gdbarch_addr_bits_remove
2285 (target_gdbarch (), gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2289 /* On at least some versions of Solaris there's a dynamic relocation
2290 on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
2291 we get control before the dynamic linker has self-relocated.
2292 Check if SYM_ADDR is in a known section, if it is assume we can
2293 trust its value. This is just a heuristic though, it could go away
2294 or be replaced if it's getting in the way.
2296 On ARM we need to know whether the ISA of rtld_db_dlactivity (or
2297 however it's spelled in your particular system) is ARM or Thumb.
2298 That knowledge is encoded in the address, if it's Thumb the low bit
2299 is 1. However, we've stripped that info above and it's not clear
2300 what all the consequences are of passing a non-addr_bits_remove'd
2301 address to svr4_create_solib_event_breakpoints. The call to
2302 find_pc_section verifies we know about the address and have some
2303 hope of computing the right kind of breakpoint to use (via
2304 symbol info). It does mean that GDB needs to be pointed at a
2305 non-stripped version of the dynamic linker in order to obtain
2306 information it already knows about. Sigh. */
2308 os
= find_pc_section (sym_addr
);
2311 /* Record the relocated start and end address of the dynamic linker
2312 text and plt section for svr4_in_dynsym_resolve_code. */
2314 CORE_ADDR load_addr
;
2316 tmp_bfd
= os
->objfile
->obfd
;
2317 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
2318 SECT_OFF_TEXT (os
->objfile
));
2320 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
2323 info
->interp_text_sect_low
=
2324 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
2325 info
->interp_text_sect_high
=
2326 info
->interp_text_sect_low
2327 + bfd_section_size (tmp_bfd
, interp_sect
);
2329 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
2332 info
->interp_plt_sect_low
=
2333 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
2334 info
->interp_plt_sect_high
=
2335 info
->interp_plt_sect_low
2336 + bfd_section_size (tmp_bfd
, interp_sect
);
2339 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2344 /* Find the program interpreter; if not found, warn the user and drop
2345 into the old breakpoint at symbol code. */
2346 interp_name
= find_program_interpreter ();
2349 CORE_ADDR load_addr
= 0;
2350 int load_addr_found
= 0;
2351 int loader_found_in_list
= 0;
2353 struct target_ops
*tmp_bfd_target
;
2357 /* Now we need to figure out where the dynamic linker was
2358 loaded so that we can load its symbols and place a breakpoint
2359 in the dynamic linker itself.
2361 This address is stored on the stack. However, I've been unable
2362 to find any magic formula to find it for Solaris (appears to
2363 be trivial on GNU/Linux). Therefore, we have to try an alternate
2364 mechanism to find the dynamic linker's base address. */
2366 gdb_bfd_ref_ptr tmp_bfd
;
2369 tmp_bfd
= solib_bfd_open (interp_name
);
2371 CATCH (ex
, RETURN_MASK_ALL
)
2376 if (tmp_bfd
== NULL
)
2377 goto bkpt_at_symbol
;
2379 /* Now convert the TMP_BFD into a target. That way target, as
2380 well as BFD operations can be used. target_bfd_reopen
2381 acquires its own reference. */
2382 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
.get ());
2384 /* On a running target, we can get the dynamic linker's base
2385 address from the shared library table. */
2386 so
= master_so_list ();
2389 if (svr4_same_1 (interp_name
, so
->so_original_name
))
2391 load_addr_found
= 1;
2392 loader_found_in_list
= 1;
2393 load_addr
= lm_addr_check (so
, tmp_bfd
.get ());
2399 /* If we were not able to find the base address of the loader
2400 from our so_list, then try using the AT_BASE auxilliary entry. */
2401 if (!load_addr_found
)
2402 if (target_auxv_search (¤t_target
, AT_BASE
, &load_addr
) > 0)
2404 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
2406 /* Ensure LOAD_ADDR has proper sign in its possible upper bits so
2407 that `+ load_addr' will overflow CORE_ADDR width not creating
2408 invalid addresses like 0x101234567 for 32bit inferiors on 64bit
2411 if (addr_bit
< (sizeof (CORE_ADDR
) * HOST_CHAR_BIT
))
2413 CORE_ADDR space_size
= (CORE_ADDR
) 1 << addr_bit
;
2414 CORE_ADDR tmp_entry_point
= exec_entry_point (tmp_bfd
.get (),
2417 gdb_assert (load_addr
< space_size
);
2419 /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked
2420 64bit ld.so with 32bit executable, it should not happen. */
2422 if (tmp_entry_point
< space_size
2423 && tmp_entry_point
+ load_addr
>= space_size
)
2424 load_addr
-= space_size
;
2427 load_addr_found
= 1;
2430 /* Otherwise we find the dynamic linker's base address by examining
2431 the current pc (which should point at the entry point for the
2432 dynamic linker) and subtracting the offset of the entry point.
2434 This is more fragile than the previous approaches, but is a good
2435 fallback method because it has actually been working well in
2437 if (!load_addr_found
)
2439 struct regcache
*regcache
2440 = get_thread_arch_regcache (inferior_ptid
, target_gdbarch ());
2442 load_addr
= (regcache_read_pc (regcache
)
2443 - exec_entry_point (tmp_bfd
.get (), tmp_bfd_target
));
2446 if (!loader_found_in_list
)
2448 info
->debug_loader_name
= xstrdup (interp_name
);
2449 info
->debug_loader_offset_p
= 1;
2450 info
->debug_loader_offset
= load_addr
;
2451 solib_add (NULL
, from_tty
, auto_solib_add
);
2454 /* Record the relocated start and end address of the dynamic linker
2455 text and plt section for svr4_in_dynsym_resolve_code. */
2456 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".text");
2459 info
->interp_text_sect_low
=
2460 bfd_section_vma (tmp_bfd
.get (), interp_sect
) + load_addr
;
2461 info
->interp_text_sect_high
=
2462 info
->interp_text_sect_low
2463 + bfd_section_size (tmp_bfd
.get (), interp_sect
);
2465 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".plt");
2468 info
->interp_plt_sect_low
=
2469 bfd_section_vma (tmp_bfd
.get (), interp_sect
) + load_addr
;
2470 info
->interp_plt_sect_high
=
2471 info
->interp_plt_sect_low
2472 + bfd_section_size (tmp_bfd
.get (), interp_sect
);
2475 /* Now try to set a breakpoint in the dynamic linker. */
2476 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2478 sym_addr
= gdb_bfd_lookup_symbol (tmp_bfd
.get (),
2479 cmp_name_and_sec_flags
,
2486 /* Convert 'sym_addr' from a function pointer to an address.
2487 Because we pass tmp_bfd_target instead of the current
2488 target, this will always produce an unrelocated value. */
2489 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2493 /* We're done with both the temporary bfd and target. Closing
2494 the target closes the underlying bfd, because it holds the
2495 only remaining reference. */
2496 target_close (tmp_bfd_target
);
2500 svr4_create_solib_event_breakpoints (target_gdbarch (),
2501 load_addr
+ sym_addr
);
2502 xfree (interp_name
);
2506 /* For whatever reason we couldn't set a breakpoint in the dynamic
2507 linker. Warn and drop into the old code. */
2509 xfree (interp_name
);
2510 warning (_("Unable to find dynamic linker breakpoint function.\n"
2511 "GDB will be unable to debug shared library initializers\n"
2512 "and track explicitly loaded dynamic code."));
2515 /* Scan through the lists of symbols, trying to look up the symbol and
2516 set a breakpoint there. Terminate loop when we/if we succeed. */
2518 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2520 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
2521 if ((msymbol
.minsym
!= NULL
)
2522 && (BMSYMBOL_VALUE_ADDRESS (msymbol
) != 0))
2524 sym_addr
= BMSYMBOL_VALUE_ADDRESS (msymbol
);
2525 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2528 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2533 if (interp_name
!= NULL
&& !current_inferior ()->attach_flag
)
2535 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2537 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
2538 if ((msymbol
.minsym
!= NULL
)
2539 && (BMSYMBOL_VALUE_ADDRESS (msymbol
) != 0))
2541 sym_addr
= BMSYMBOL_VALUE_ADDRESS (msymbol
);
2542 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2545 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2553 /* Read the ELF program headers from ABFD. Return the contents and
2554 set *PHDRS_SIZE to the size of the program headers. */
2557 read_program_headers_from_bfd (bfd
*abfd
, int *phdrs_size
)
2559 Elf_Internal_Ehdr
*ehdr
;
2562 ehdr
= elf_elfheader (abfd
);
2564 *phdrs_size
= ehdr
->e_phnum
* ehdr
->e_phentsize
;
2565 if (*phdrs_size
== 0)
2568 buf
= (gdb_byte
*) xmalloc (*phdrs_size
);
2569 if (bfd_seek (abfd
, ehdr
->e_phoff
, SEEK_SET
) != 0
2570 || bfd_bread (buf
, *phdrs_size
, abfd
) != *phdrs_size
)
2579 /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior
2580 exec_bfd. Otherwise return 0.
2582 We relocate all of the sections by the same amount. This
2583 behavior is mandated by recent editions of the System V ABI.
2584 According to the System V Application Binary Interface,
2585 Edition 4.1, page 5-5:
2587 ... Though the system chooses virtual addresses for
2588 individual processes, it maintains the segments' relative
2589 positions. Because position-independent code uses relative
2590 addressesing between segments, the difference between
2591 virtual addresses in memory must match the difference
2592 between virtual addresses in the file. The difference
2593 between the virtual address of any segment in memory and
2594 the corresponding virtual address in the file is thus a
2595 single constant value for any one executable or shared
2596 object in a given process. This difference is the base
2597 address. One use of the base address is to relocate the
2598 memory image of the program during dynamic linking.
2600 The same language also appears in Edition 4.0 of the System V
2601 ABI and is left unspecified in some of the earlier editions.
2603 Decide if the objfile needs to be relocated. As indicated above, we will
2604 only be here when execution is stopped. But during attachment PC can be at
2605 arbitrary address therefore regcache_read_pc can be misleading (contrary to
2606 the auxv AT_ENTRY value). Moreover for executable with interpreter section
2607 regcache_read_pc would point to the interpreter and not the main executable.
2609 So, to summarize, relocations are necessary when the start address obtained
2610 from the executable is different from the address in auxv AT_ENTRY entry.
2612 [ The astute reader will note that we also test to make sure that
2613 the executable in question has the DYNAMIC flag set. It is my
2614 opinion that this test is unnecessary (undesirable even). It
2615 was added to avoid inadvertent relocation of an executable
2616 whose e_type member in the ELF header is not ET_DYN. There may
2617 be a time in the future when it is desirable to do relocations
2618 on other types of files as well in which case this condition
2619 should either be removed or modified to accomodate the new file
2620 type. - Kevin, Nov 2000. ] */
2623 svr4_exec_displacement (CORE_ADDR
*displacementp
)
2625 /* ENTRY_POINT is a possible function descriptor - before
2626 a call to gdbarch_convert_from_func_ptr_addr. */
2627 CORE_ADDR entry_point
, exec_displacement
;
2629 if (exec_bfd
== NULL
)
2632 /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries
2633 being executed themselves and PIE (Position Independent Executable)
2634 executables are ET_DYN. */
2636 if ((bfd_get_file_flags (exec_bfd
) & DYNAMIC
) == 0)
2639 if (target_auxv_search (¤t_target
, AT_ENTRY
, &entry_point
) <= 0)
2642 exec_displacement
= entry_point
- bfd_get_start_address (exec_bfd
);
2644 /* Verify the EXEC_DISPLACEMENT candidate complies with the required page
2645 alignment. It is cheaper than the program headers comparison below. */
2647 if (bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
2649 const struct elf_backend_data
*elf
= get_elf_backend_data (exec_bfd
);
2651 /* p_align of PT_LOAD segments does not specify any alignment but
2652 only congruency of addresses:
2653 p_offset % p_align == p_vaddr % p_align
2654 Kernel is free to load the executable with lower alignment. */
2656 if ((exec_displacement
& (elf
->minpagesize
- 1)) != 0)
2660 /* Verify that the auxilliary vector describes the same file as exec_bfd, by
2661 comparing their program headers. If the program headers in the auxilliary
2662 vector do not match the program headers in the executable, then we are
2663 looking at a different file than the one used by the kernel - for
2664 instance, "gdb program" connected to "gdbserver :PORT ld.so program". */
2666 if (bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
2668 /* Be optimistic and clear OK only if GDB was able to verify the headers
2669 really do not match. */
2670 int phdrs_size
, phdrs2_size
, ok
= 1;
2671 gdb_byte
*buf
, *buf2
;
2674 buf
= read_program_header (-1, &phdrs_size
, &arch_size
, NULL
);
2675 buf2
= read_program_headers_from_bfd (exec_bfd
, &phdrs2_size
);
2676 if (buf
!= NULL
&& buf2
!= NULL
)
2678 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
2680 /* We are dealing with three different addresses. EXEC_BFD
2681 represents current address in on-disk file. target memory content
2682 may be different from EXEC_BFD as the file may have been prelinked
2683 to a different address after the executable has been loaded.
2684 Moreover the address of placement in target memory can be
2685 different from what the program headers in target memory say -
2686 this is the goal of PIE.
2688 Detected DISPLACEMENT covers both the offsets of PIE placement and
2689 possible new prelink performed after start of the program. Here
2690 relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
2691 content offset for the verification purpose. */
2693 if (phdrs_size
!= phdrs2_size
2694 || bfd_get_arch_size (exec_bfd
) != arch_size
)
2696 else if (arch_size
== 32
2697 && phdrs_size
>= sizeof (Elf32_External_Phdr
)
2698 && phdrs_size
% sizeof (Elf32_External_Phdr
) == 0)
2700 Elf_Internal_Ehdr
*ehdr2
= elf_tdata (exec_bfd
)->elf_header
;
2701 Elf_Internal_Phdr
*phdr2
= elf_tdata (exec_bfd
)->phdr
;
2702 CORE_ADDR displacement
= 0;
2705 /* DISPLACEMENT could be found more easily by the difference of
2706 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2707 already have enough information to compute that displacement
2708 with what we've read. */
2710 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2711 if (phdr2
[i
].p_type
== PT_LOAD
)
2713 Elf32_External_Phdr
*phdrp
;
2714 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2715 CORE_ADDR vaddr
, paddr
;
2716 CORE_ADDR displacement_vaddr
= 0;
2717 CORE_ADDR displacement_paddr
= 0;
2719 phdrp
= &((Elf32_External_Phdr
*) buf
)[i
];
2720 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2721 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2723 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2725 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2727 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2729 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2731 if (displacement_vaddr
== displacement_paddr
)
2732 displacement
= displacement_vaddr
;
2737 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2739 for (i
= 0; i
< phdrs_size
/ sizeof (Elf32_External_Phdr
); i
++)
2741 Elf32_External_Phdr
*phdrp
;
2742 Elf32_External_Phdr
*phdr2p
;
2743 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2744 CORE_ADDR vaddr
, paddr
;
2745 asection
*plt2_asect
;
2747 phdrp
= &((Elf32_External_Phdr
*) buf
)[i
];
2748 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2749 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2750 phdr2p
= &((Elf32_External_Phdr
*) buf2
)[i
];
2752 /* PT_GNU_STACK is an exception by being never relocated by
2753 prelink as its addresses are always zero. */
2755 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2758 /* Check also other adjustment combinations - PR 11786. */
2760 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2762 vaddr
-= displacement
;
2763 store_unsigned_integer (buf_vaddr_p
, 4, byte_order
, vaddr
);
2765 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2767 paddr
-= displacement
;
2768 store_unsigned_integer (buf_paddr_p
, 4, byte_order
, paddr
);
2770 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2773 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2774 CentOS-5 has problems with filesz, memsz as well.
2776 if (phdr2
[i
].p_type
== PT_GNU_RELRO
)
2778 Elf32_External_Phdr tmp_phdr
= *phdrp
;
2779 Elf32_External_Phdr tmp_phdr2
= *phdr2p
;
2781 memset (tmp_phdr
.p_filesz
, 0, 4);
2782 memset (tmp_phdr
.p_memsz
, 0, 4);
2783 memset (tmp_phdr
.p_flags
, 0, 4);
2784 memset (tmp_phdr
.p_align
, 0, 4);
2785 memset (tmp_phdr2
.p_filesz
, 0, 4);
2786 memset (tmp_phdr2
.p_memsz
, 0, 4);
2787 memset (tmp_phdr2
.p_flags
, 0, 4);
2788 memset (tmp_phdr2
.p_align
, 0, 4);
2790 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2795 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2796 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2800 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2803 content2
= (bfd_get_section_flags (exec_bfd
, plt2_asect
)
2804 & SEC_HAS_CONTENTS
) != 0;
2806 filesz
= extract_unsigned_integer (buf_filesz_p
, 4,
2809 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2810 FILESZ is from the in-memory image. */
2812 filesz
+= bfd_get_section_size (plt2_asect
);
2814 filesz
-= bfd_get_section_size (plt2_asect
);
2816 store_unsigned_integer (buf_filesz_p
, 4, byte_order
,
2819 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2827 else if (arch_size
== 64
2828 && phdrs_size
>= sizeof (Elf64_External_Phdr
)
2829 && phdrs_size
% sizeof (Elf64_External_Phdr
) == 0)
2831 Elf_Internal_Ehdr
*ehdr2
= elf_tdata (exec_bfd
)->elf_header
;
2832 Elf_Internal_Phdr
*phdr2
= elf_tdata (exec_bfd
)->phdr
;
2833 CORE_ADDR displacement
= 0;
2836 /* DISPLACEMENT could be found more easily by the difference of
2837 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2838 already have enough information to compute that displacement
2839 with what we've read. */
2841 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2842 if (phdr2
[i
].p_type
== PT_LOAD
)
2844 Elf64_External_Phdr
*phdrp
;
2845 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2846 CORE_ADDR vaddr
, paddr
;
2847 CORE_ADDR displacement_vaddr
= 0;
2848 CORE_ADDR displacement_paddr
= 0;
2850 phdrp
= &((Elf64_External_Phdr
*) buf
)[i
];
2851 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2852 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2854 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2856 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2858 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2860 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2862 if (displacement_vaddr
== displacement_paddr
)
2863 displacement
= displacement_vaddr
;
2868 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2870 for (i
= 0; i
< phdrs_size
/ sizeof (Elf64_External_Phdr
); i
++)
2872 Elf64_External_Phdr
*phdrp
;
2873 Elf64_External_Phdr
*phdr2p
;
2874 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2875 CORE_ADDR vaddr
, paddr
;
2876 asection
*plt2_asect
;
2878 phdrp
= &((Elf64_External_Phdr
*) buf
)[i
];
2879 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2880 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2881 phdr2p
= &((Elf64_External_Phdr
*) buf2
)[i
];
2883 /* PT_GNU_STACK is an exception by being never relocated by
2884 prelink as its addresses are always zero. */
2886 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2889 /* Check also other adjustment combinations - PR 11786. */
2891 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2893 vaddr
-= displacement
;
2894 store_unsigned_integer (buf_vaddr_p
, 8, byte_order
, vaddr
);
2896 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2898 paddr
-= displacement
;
2899 store_unsigned_integer (buf_paddr_p
, 8, byte_order
, paddr
);
2901 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2904 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2905 CentOS-5 has problems with filesz, memsz as well.
2907 if (phdr2
[i
].p_type
== PT_GNU_RELRO
)
2909 Elf64_External_Phdr tmp_phdr
= *phdrp
;
2910 Elf64_External_Phdr tmp_phdr2
= *phdr2p
;
2912 memset (tmp_phdr
.p_filesz
, 0, 8);
2913 memset (tmp_phdr
.p_memsz
, 0, 8);
2914 memset (tmp_phdr
.p_flags
, 0, 4);
2915 memset (tmp_phdr
.p_align
, 0, 8);
2916 memset (tmp_phdr2
.p_filesz
, 0, 8);
2917 memset (tmp_phdr2
.p_memsz
, 0, 8);
2918 memset (tmp_phdr2
.p_flags
, 0, 4);
2919 memset (tmp_phdr2
.p_align
, 0, 8);
2921 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2926 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2927 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2931 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2934 content2
= (bfd_get_section_flags (exec_bfd
, plt2_asect
)
2935 & SEC_HAS_CONTENTS
) != 0;
2937 filesz
= extract_unsigned_integer (buf_filesz_p
, 8,
2940 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2941 FILESZ is from the in-memory image. */
2943 filesz
+= bfd_get_section_size (plt2_asect
);
2945 filesz
-= bfd_get_section_size (plt2_asect
);
2947 store_unsigned_integer (buf_filesz_p
, 8, byte_order
,
2950 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2971 /* It can be printed repeatedly as there is no easy way to check
2972 the executable symbols/file has been already relocated to
2975 printf_unfiltered (_("Using PIE (Position Independent Executable) "
2976 "displacement %s for \"%s\".\n"),
2977 paddress (target_gdbarch (), exec_displacement
),
2978 bfd_get_filename (exec_bfd
));
2981 *displacementp
= exec_displacement
;
2985 /* Relocate the main executable. This function should be called upon
2986 stopping the inferior process at the entry point to the program.
2987 The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
2988 different, the main executable is relocated by the proper amount. */
2991 svr4_relocate_main_executable (void)
2993 CORE_ADDR displacement
;
2995 /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS
2996 probably contains the offsets computed using the PIE displacement
2997 from the previous run, which of course are irrelevant for this run.
2998 So we need to determine the new PIE displacement and recompute the
2999 section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS
3000 already contains pre-computed offsets.
3002 If we cannot compute the PIE displacement, either:
3004 - The executable is not PIE.
3006 - SYMFILE_OBJFILE does not match the executable started in the target.
3007 This can happen for main executable symbols loaded at the host while
3008 `ld.so --ld-args main-executable' is loaded in the target.
3010 Then we leave the section offsets untouched and use them as is for
3013 - These section offsets were properly reset earlier, and thus
3014 already contain the correct values. This can happen for instance
3015 when reconnecting via the remote protocol to a target that supports
3016 the `qOffsets' packet.
3018 - The section offsets were not reset earlier, and the best we can
3019 hope is that the old offsets are still applicable to the new run. */
3021 if (! svr4_exec_displacement (&displacement
))
3024 /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file
3027 if (symfile_objfile
)
3029 struct section_offsets
*new_offsets
;
3032 new_offsets
= XALLOCAVEC (struct section_offsets
,
3033 symfile_objfile
->num_sections
);
3035 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
3036 new_offsets
->offsets
[i
] = displacement
;
3038 objfile_relocate (symfile_objfile
, new_offsets
);
3044 for (asect
= exec_bfd
->sections
; asect
!= NULL
; asect
= asect
->next
)
3045 exec_set_section_address (bfd_get_filename (exec_bfd
), asect
->index
,
3046 (bfd_section_vma (exec_bfd
, asect
)
3051 /* Implement the "create_inferior_hook" target_solib_ops method.
3053 For SVR4 executables, this first instruction is either the first
3054 instruction in the dynamic linker (for dynamically linked
3055 executables) or the instruction at "start" for statically linked
3056 executables. For dynamically linked executables, the system
3057 first exec's /lib/libc.so.N, which contains the dynamic linker,
3058 and starts it running. The dynamic linker maps in any needed
3059 shared libraries, maps in the actual user executable, and then
3060 jumps to "start" in the user executable.
3062 We can arrange to cooperate with the dynamic linker to discover the
3063 names of shared libraries that are dynamically linked, and the base
3064 addresses to which they are linked.
3066 This function is responsible for discovering those names and
3067 addresses, and saving sufficient information about them to allow
3068 their symbols to be read at a later time. */
3071 svr4_solib_create_inferior_hook (int from_tty
)
3073 struct svr4_info
*info
;
3075 info
= get_svr4_info ();
3077 /* Clear the probes-based interface's state. */
3078 free_probes_table (info
);
3079 free_solib_list (info
);
3081 /* Relocate the main executable if necessary. */
3082 svr4_relocate_main_executable ();
3084 /* No point setting a breakpoint in the dynamic linker if we can't
3085 hit it (e.g., a core file, or a trace file). */
3086 if (!target_has_execution
)
3089 if (!svr4_have_link_map_offsets ())
3092 if (!enable_break (info
, from_tty
))
3097 svr4_clear_solib (void)
3099 struct svr4_info
*info
;
3101 info
= get_svr4_info ();
3102 info
->debug_base
= 0;
3103 info
->debug_loader_offset_p
= 0;
3104 info
->debug_loader_offset
= 0;
3105 xfree (info
->debug_loader_name
);
3106 info
->debug_loader_name
= NULL
;
3109 /* Clear any bits of ADDR that wouldn't fit in a target-format
3110 data pointer. "Data pointer" here refers to whatever sort of
3111 address the dynamic linker uses to manage its sections. At the
3112 moment, we don't support shared libraries on any processors where
3113 code and data pointers are different sizes.
3115 This isn't really the right solution. What we really need here is
3116 a way to do arithmetic on CORE_ADDR values that respects the
3117 natural pointer/address correspondence. (For example, on the MIPS,
3118 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
3119 sign-extend the value. There, simply truncating the bits above
3120 gdbarch_ptr_bit, as we do below, is no good.) This should probably
3121 be a new gdbarch method or something. */
3123 svr4_truncate_ptr (CORE_ADDR addr
)
3125 if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR
) * 8)
3126 /* We don't need to truncate anything, and the bit twiddling below
3127 will fail due to overflow problems. */
3130 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1);
3135 svr4_relocate_section_addresses (struct so_list
*so
,
3136 struct target_section
*sec
)
3138 bfd
*abfd
= sec
->the_bfd_section
->owner
;
3140 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ lm_addr_check (so
, abfd
));
3141 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ lm_addr_check (so
, abfd
));
3145 /* Architecture-specific operations. */
3147 /* Per-architecture data key. */
3148 static struct gdbarch_data
*solib_svr4_data
;
3150 struct solib_svr4_ops
3152 /* Return a description of the layout of `struct link_map'. */
3153 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
3156 /* Return a default for the architecture-specific operations. */
3159 solib_svr4_init (struct obstack
*obstack
)
3161 struct solib_svr4_ops
*ops
;
3163 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
3164 ops
->fetch_link_map_offsets
= NULL
;
3168 /* Set the architecture-specific `struct link_map_offsets' fetcher for
3169 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
3172 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
3173 struct link_map_offsets
*(*flmo
) (void))
3175 struct solib_svr4_ops
*ops
3176 = (struct solib_svr4_ops
*) gdbarch_data (gdbarch
, solib_svr4_data
);
3178 ops
->fetch_link_map_offsets
= flmo
;
3180 set_solib_ops (gdbarch
, &svr4_so_ops
);
3183 /* Fetch a link_map_offsets structure using the architecture-specific
3184 `struct link_map_offsets' fetcher. */
3186 static struct link_map_offsets
*
3187 svr4_fetch_link_map_offsets (void)
3189 struct solib_svr4_ops
*ops
3190 = (struct solib_svr4_ops
*) gdbarch_data (target_gdbarch (),
3193 gdb_assert (ops
->fetch_link_map_offsets
);
3194 return ops
->fetch_link_map_offsets ();
3197 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
3200 svr4_have_link_map_offsets (void)
3202 struct solib_svr4_ops
*ops
3203 = (struct solib_svr4_ops
*) gdbarch_data (target_gdbarch (),
3206 return (ops
->fetch_link_map_offsets
!= NULL
);
3210 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
3211 `struct r_debug' and a `struct link_map' that are binary compatible
3212 with the origional SVR4 implementation. */
3214 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3215 for an ILP32 SVR4 system. */
3217 struct link_map_offsets
*
3218 svr4_ilp32_fetch_link_map_offsets (void)
3220 static struct link_map_offsets lmo
;
3221 static struct link_map_offsets
*lmp
= NULL
;
3227 lmo
.r_version_offset
= 0;
3228 lmo
.r_version_size
= 4;
3229 lmo
.r_map_offset
= 4;
3230 lmo
.r_brk_offset
= 8;
3231 lmo
.r_ldsomap_offset
= 20;
3233 /* Everything we need is in the first 20 bytes. */
3234 lmo
.link_map_size
= 20;
3235 lmo
.l_addr_offset
= 0;
3236 lmo
.l_name_offset
= 4;
3237 lmo
.l_ld_offset
= 8;
3238 lmo
.l_next_offset
= 12;
3239 lmo
.l_prev_offset
= 16;
3245 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3246 for an LP64 SVR4 system. */
3248 struct link_map_offsets
*
3249 svr4_lp64_fetch_link_map_offsets (void)
3251 static struct link_map_offsets lmo
;
3252 static struct link_map_offsets
*lmp
= NULL
;
3258 lmo
.r_version_offset
= 0;
3259 lmo
.r_version_size
= 4;
3260 lmo
.r_map_offset
= 8;
3261 lmo
.r_brk_offset
= 16;
3262 lmo
.r_ldsomap_offset
= 40;
3264 /* Everything we need is in the first 40 bytes. */
3265 lmo
.link_map_size
= 40;
3266 lmo
.l_addr_offset
= 0;
3267 lmo
.l_name_offset
= 8;
3268 lmo
.l_ld_offset
= 16;
3269 lmo
.l_next_offset
= 24;
3270 lmo
.l_prev_offset
= 32;
3277 struct target_so_ops svr4_so_ops
;
3279 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
3280 different rule for symbol lookup. The lookup begins here in the DSO, not in
3281 the main executable. */
3283 static struct block_symbol
3284 elf_lookup_lib_symbol (struct objfile
*objfile
,
3286 const domain_enum domain
)
3290 if (objfile
== symfile_objfile
)
3294 /* OBJFILE should have been passed as the non-debug one. */
3295 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
3297 abfd
= objfile
->obfd
;
3300 if (abfd
== NULL
|| scan_dyntag (DT_SYMBOLIC
, abfd
, NULL
, NULL
) != 1)
3301 return (struct block_symbol
) {NULL
, NULL
};
3303 return lookup_global_symbol_from_objfile (objfile
, name
, domain
);
3306 extern initialize_file_ftype _initialize_svr4_solib
; /* -Wmissing-prototypes */
3309 _initialize_svr4_solib (void)
3311 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
3312 solib_svr4_pspace_data
3313 = register_program_space_data_with_cleanup (NULL
, svr4_pspace_data_cleanup
);
3315 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
3316 svr4_so_ops
.free_so
= svr4_free_so
;
3317 svr4_so_ops
.clear_so
= svr4_clear_so
;
3318 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
3319 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
3320 svr4_so_ops
.current_sos
= svr4_current_sos
;
3321 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
3322 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
3323 svr4_so_ops
.bfd_open
= solib_bfd_open
;
3324 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
3325 svr4_so_ops
.same
= svr4_same
;
3326 svr4_so_ops
.keep_data_in_core
= svr4_keep_data_in_core
;
3327 svr4_so_ops
.update_breakpoints
= svr4_update_solib_event_breakpoints
;
3328 svr4_so_ops
.handle_event
= svr4_handle_solib_event
;