1 /* Handle SVR4 shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990-2015 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 /* Link map info to include in an allocated so_list entry. */
58 /* Amount by which addresses in the binary should be relocated to
59 match the inferior. The direct inferior value is L_ADDR_INFERIOR.
60 When prelinking is involved and the prelink base address changes,
61 we may need a different offset - the recomputed offset is in L_ADDR.
62 It is commonly the same value. It is cached as we want to warn about
63 the difference and compute it only once. L_ADDR is valid
65 CORE_ADDR l_addr, l_addr_inferior;
66 unsigned int l_addr_p : 1;
68 /* The target location of lm. */
71 /* Values read in from inferior's fields of the same name. */
72 CORE_ADDR l_ld, l_next, l_prev, l_name;
75 /* On SVR4 systems, a list of symbols in the dynamic linker where
76 GDB can try to place a breakpoint to monitor shared library
79 If none of these symbols are found, or other errors occur, then
80 SVR4 systems will fall back to using a symbol as the "startup
81 mapping complete" breakpoint address. */
83 static const char * const solib_break_names[] =
89 "__dl_rtld_db_dlactivity",
95 static const char * const bkpt_names[] =
103 static const char * const main_name_list[] =
109 /* What to do when a probe stop occurs. */
113 /* Something went seriously wrong. Stop using probes and
114 revert to using the older interface. */
115 PROBES_INTERFACE_FAILED,
117 /* No action is required. The shared object list is still
121 /* The shared object list should be reloaded entirely. */
124 /* Attempt to incrementally update the shared object list. If
125 the update fails or is not possible, fall back to reloading
130 /* A probe's name and its associated action. */
134 /* The name of the probe. */
137 /* What to do when a probe stop occurs. */
138 enum probe_action action;
141 /* A list of named probes and their associated actions. If all
142 probes are present in the dynamic linker then the probes-based
143 interface will be used. */
145 static const struct probe_info probe_info[] =
147 { "init_start", DO_NOTHING },
148 { "init_complete", FULL_RELOAD },
149 { "map_start", DO_NOTHING },
150 { "map_failed", DO_NOTHING },
151 { "reloc_complete", UPDATE_OR_RELOAD },
152 { "unmap_start", DO_NOTHING },
153 { "unmap_complete", FULL_RELOAD },
156 #define NUM_PROBES ARRAY_SIZE (probe_info)
158 /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
159 the same shared library. */
162 svr4_same_1 (const char *gdb_so_name, const char *inferior_so_name)
164 if (strcmp (gdb_so_name, inferior_so_name) == 0)
167 /* On Solaris, when starting inferior we think that dynamic linker is
168 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
169 contains /lib/ld.so.1. Sometimes one file is a link to another, but
170 sometimes they have identical content, but are not linked to each
171 other. We don't restrict this check for Solaris, but the chances
172 of running into this situation elsewhere are very low. */
173 if (strcmp (gdb_so_name, "/usr/lib/ld.so.1") == 0
174 && strcmp (inferior_so_name, "/lib/ld.so.1") == 0)
177 /* Similarly, we observed the same issue with sparc64, but with
178 different locations. */
179 if (strcmp (gdb_so_name, "/usr/lib/sparcv9/ld.so.1") == 0
180 && strcmp (inferior_so_name, "/lib/sparcv9/ld.so.1") == 0)
187 svr4_same (struct so_list *gdb, struct so_list *inferior)
189 return (svr4_same_1 (gdb->so_original_name, inferior->so_original_name));
192 static struct lm_info *
193 lm_info_read (CORE_ADDR lm_addr)
195 struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
197 struct lm_info *lm_info;
198 struct cleanup *back_to;
200 lm = xmalloc (lmo->link_map_size);
201 back_to = make_cleanup (xfree, lm);
203 if (target_read_memory (lm_addr, lm, lmo->link_map_size) != 0)
205 warning (_("Error reading shared library list entry at %s"),
206 paddress (target_gdbarch (), lm_addr)),
211 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
213 lm_info = xzalloc (sizeof (*lm_info));
214 lm_info->lm_addr = lm_addr;
216 lm_info->l_addr_inferior = extract_typed_address (&lm[lmo->l_addr_offset],
218 lm_info->l_ld = extract_typed_address (&lm[lmo->l_ld_offset], ptr_type);
219 lm_info->l_next = extract_typed_address (&lm[lmo->l_next_offset],
221 lm_info->l_prev = extract_typed_address (&lm[lmo->l_prev_offset],
223 lm_info->l_name = extract_typed_address (&lm[lmo->l_name_offset],
227 do_cleanups (back_to);
233 has_lm_dynamic_from_link_map (void)
235 struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
237 return lmo->l_ld_offset >= 0;
241 lm_addr_check (const struct so_list *so, bfd *abfd)
243 if (!so->lm_info->l_addr_p)
245 struct bfd_section *dyninfo_sect;
246 CORE_ADDR l_addr, l_dynaddr, dynaddr;
248 l_addr = so->lm_info->l_addr_inferior;
250 if (! abfd || ! has_lm_dynamic_from_link_map ())
253 l_dynaddr = so->lm_info->l_ld;
255 dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic");
256 if (dyninfo_sect == NULL)
259 dynaddr = bfd_section_vma (abfd, dyninfo_sect);
261 if (dynaddr + l_addr != l_dynaddr)
263 CORE_ADDR align = 0x1000;
264 CORE_ADDR minpagesize = align;
266 if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
268 Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header;
269 Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr;
274 for (i = 0; i < ehdr->e_phnum; i++)
275 if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align)
276 align = phdr[i].p_align;
278 minpagesize = get_elf_backend_data (abfd)->minpagesize;
281 /* Turn it into a mask. */
284 /* If the changes match the alignment requirements, we
285 assume we're using a core file that was generated by the
286 same binary, just prelinked with a different base offset.
287 If it doesn't match, we may have a different binary, the
288 same binary with the dynamic table loaded at an unrelated
289 location, or anything, really. To avoid regressions,
290 don't adjust the base offset in the latter case, although
291 odds are that, if things really changed, debugging won't
294 One could expect more the condition
295 ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
296 but the one below is relaxed for PPC. The PPC kernel supports
297 either 4k or 64k page sizes. To be prepared for 64k pages,
298 PPC ELF files are built using an alignment requirement of 64k.
299 However, when running on a kernel supporting 4k pages, the memory
300 mapping of the library may not actually happen on a 64k boundary!
302 (In the usual case where (l_addr & align) == 0, this check is
303 equivalent to the possibly expected check above.)
305 Even on PPC it must be zero-aligned at least for MINPAGESIZE. */
307 l_addr = l_dynaddr - dynaddr;
309 if ((l_addr & (minpagesize - 1)) == 0
310 && (l_addr & align) == ((l_dynaddr - dynaddr) & align))
313 printf_unfiltered (_("Using PIC (Position Independent Code) "
314 "prelink displacement %s for \"%s\".\n"),
315 paddress (target_gdbarch (), l_addr),
320 /* There is no way to verify the library file matches. prelink
321 can during prelinking of an unprelinked file (or unprelinking
322 of a prelinked file) shift the DYNAMIC segment by arbitrary
323 offset without any page size alignment. There is no way to
324 find out the ELF header and/or Program Headers for a limited
325 verification if it they match. One could do a verification
326 of the DYNAMIC segment. Still the found address is the best
327 one GDB could find. */
329 warning (_(".dynamic section for \"%s\" "
330 "is not at the expected address "
331 "(wrong library or version mismatch?)"), so->so_name);
336 so->lm_info->l_addr = l_addr;
337 so->lm_info->l_addr_p = 1;
340 return so->lm_info->l_addr;
343 /* Per pspace SVR4 specific data. */
347 CORE_ADDR debug_base; /* Base of dynamic linker structures. */
349 /* Validity flag for debug_loader_offset. */
350 int debug_loader_offset_p;
352 /* Load address for the dynamic linker, inferred. */
353 CORE_ADDR debug_loader_offset;
355 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
356 char *debug_loader_name;
358 /* Load map address for the main executable. */
359 CORE_ADDR main_lm_addr;
361 CORE_ADDR interp_text_sect_low;
362 CORE_ADDR interp_text_sect_high;
363 CORE_ADDR interp_plt_sect_low;
364 CORE_ADDR interp_plt_sect_high;
366 /* Nonzero if the list of objects was last obtained from the target
367 via qXfer:libraries-svr4:read. */
370 /* Table of struct probe_and_action instances, used by the
371 probes-based interface to map breakpoint addresses to probes
372 and their associated actions. Lookup is performed using
373 probe_and_action->probe->address. */
376 /* List of objects loaded into the inferior, used by the probes-
378 struct so_list *solib_list;
381 /* Per-program-space data key. */
382 static const struct program_space_data *solib_svr4_pspace_data;
384 /* Free the probes table. */
387 free_probes_table (struct svr4_info *info)
389 if (info->probes_table == NULL)
392 htab_delete (info->probes_table);
393 info->probes_table = NULL;
396 /* Free the solib list. */
399 free_solib_list (struct svr4_info *info)
401 svr4_free_library_list (&info->solib_list);
402 info->solib_list = NULL;
406 svr4_pspace_data_cleanup (struct program_space *pspace, void *arg)
408 struct svr4_info *info = arg;
410 free_probes_table (info);
411 free_solib_list (info);
416 /* Get the current svr4 data. If none is found yet, add it now. This
417 function always returns a valid object. */
419 static struct svr4_info *
422 struct svr4_info *info;
424 info = program_space_data (current_program_space, solib_svr4_pspace_data);
428 info = XCNEW (struct svr4_info);
429 set_program_space_data (current_program_space, solib_svr4_pspace_data, info);
433 /* Local function prototypes */
435 static int match_main (const char *);
437 /* Read program header TYPE from inferior memory. The header is found
438 by scanning the OS auxillary vector.
440 If TYPE == -1, return the program headers instead of the contents of
443 Return a pointer to allocated memory holding the program header contents,
444 or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the
445 size of those contents is returned to P_SECT_SIZE. Likewise, the target
446 architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE and
447 the base address of the section is returned in BASE_ADDR. */
450 read_program_header (int type, int *p_sect_size, int *p_arch_size,
451 CORE_ADDR *base_addr)
453 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
454 CORE_ADDR at_phdr, at_phent, at_phnum, pt_phdr = 0;
455 int arch_size, sect_size;
460 /* Get required auxv elements from target. */
461 if (target_auxv_search (¤t_target, AT_PHDR, &at_phdr) <= 0)
463 if (target_auxv_search (¤t_target, AT_PHENT, &at_phent) <= 0)
465 if (target_auxv_search (¤t_target, AT_PHNUM, &at_phnum) <= 0)
467 if (!at_phdr || !at_phnum)
470 /* Determine ELF architecture type. */
471 if (at_phent == sizeof (Elf32_External_Phdr))
473 else if (at_phent == sizeof (Elf64_External_Phdr))
478 /* Find the requested segment. */
482 sect_size = at_phent * at_phnum;
484 else if (arch_size == 32)
486 Elf32_External_Phdr phdr;
489 /* Search for requested PHDR. */
490 for (i = 0; i < at_phnum; i++)
494 if (target_read_memory (at_phdr + i * sizeof (phdr),
495 (gdb_byte *)&phdr, sizeof (phdr)))
498 p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type,
501 if (p_type == PT_PHDR)
504 pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr,
515 /* Retrieve address and size. */
516 sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
518 sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz,
523 Elf64_External_Phdr phdr;
526 /* Search for requested PHDR. */
527 for (i = 0; i < at_phnum; i++)
531 if (target_read_memory (at_phdr + i * sizeof (phdr),
532 (gdb_byte *)&phdr, sizeof (phdr)))
535 p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type,
538 if (p_type == PT_PHDR)
541 pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr,
552 /* Retrieve address and size. */
553 sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr,
555 sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz,
559 /* PT_PHDR is optional, but we really need it
560 for PIE to make this work in general. */
564 /* at_phdr is real address in memory. pt_phdr is what pheader says it is.
565 Relocation offset is the difference between the two. */
566 sect_addr = sect_addr + (at_phdr - pt_phdr);
569 /* Read in requested program header. */
570 buf = xmalloc (sect_size);
571 if (target_read_memory (sect_addr, buf, sect_size))
578 *p_arch_size = arch_size;
580 *p_sect_size = sect_size;
582 *base_addr = sect_addr;
588 /* Return program interpreter string. */
590 find_program_interpreter (void)
592 gdb_byte *buf = NULL;
594 /* If we have an exec_bfd, use its section table. */
596 && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
598 struct bfd_section *interp_sect;
600 interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
601 if (interp_sect != NULL)
603 int sect_size = bfd_section_size (exec_bfd, interp_sect);
605 buf = xmalloc (sect_size);
606 bfd_get_section_contents (exec_bfd, interp_sect, buf, 0, sect_size);
610 /* If we didn't find it, use the target auxillary vector. */
612 buf = read_program_header (PT_INTERP, NULL, NULL, NULL);
618 /* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is
619 found, 1 is returned and the corresponding PTR is set. */
622 scan_dyntag (const int desired_dyntag, bfd *abfd, CORE_ADDR *ptr,
625 int arch_size, step, sect_size;
627 CORE_ADDR dyn_ptr, dyn_addr;
628 gdb_byte *bufend, *bufstart, *buf;
629 Elf32_External_Dyn *x_dynp_32;
630 Elf64_External_Dyn *x_dynp_64;
631 struct bfd_section *sect;
632 struct target_section *target_section;
637 if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
640 arch_size = bfd_get_arch_size (abfd);
644 /* Find the start address of the .dynamic section. */
645 sect = bfd_get_section_by_name (abfd, ".dynamic");
649 for (target_section = current_target_sections->sections;
650 target_section < current_target_sections->sections_end;
652 if (sect == target_section->the_bfd_section)
654 if (target_section < current_target_sections->sections_end)
655 dyn_addr = target_section->addr;
658 /* ABFD may come from OBJFILE acting only as a symbol file without being
659 loaded into the target (see add_symbol_file_command). This case is
660 such fallback to the file VMA address without the possibility of
661 having the section relocated to its actual in-memory address. */
663 dyn_addr = bfd_section_vma (abfd, sect);
666 /* Read in .dynamic from the BFD. We will get the actual value
667 from memory later. */
668 sect_size = bfd_section_size (abfd, sect);
669 buf = bufstart = alloca (sect_size);
670 if (!bfd_get_section_contents (abfd, sect,
674 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
675 step = (arch_size == 32) ? sizeof (Elf32_External_Dyn)
676 : sizeof (Elf64_External_Dyn);
677 for (bufend = buf + sect_size;
683 x_dynp_32 = (Elf32_External_Dyn *) buf;
684 current_dyntag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag);
685 dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr);
689 x_dynp_64 = (Elf64_External_Dyn *) buf;
690 current_dyntag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag);
691 dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr);
693 if (current_dyntag == DT_NULL)
695 if (current_dyntag == desired_dyntag)
697 /* If requested, try to read the runtime value of this .dynamic
701 struct type *ptr_type;
703 CORE_ADDR ptr_addr_1;
705 ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
706 ptr_addr_1 = dyn_addr + (buf - bufstart) + arch_size / 8;
707 if (target_read_memory (ptr_addr_1, ptr_buf, arch_size / 8) == 0)
708 dyn_ptr = extract_typed_address (ptr_buf, ptr_type);
711 *ptr_addr = dyn_addr + (buf - bufstart);
720 /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable,
721 found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1
722 is returned and the corresponding PTR is set. */
725 scan_dyntag_auxv (const int desired_dyntag, CORE_ADDR *ptr,
728 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
729 int sect_size, arch_size, step;
733 gdb_byte *bufend, *bufstart, *buf;
735 /* Read in .dynamic section. */
736 buf = bufstart = read_program_header (PT_DYNAMIC, §_size, &arch_size,
741 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
742 step = (arch_size == 32) ? sizeof (Elf32_External_Dyn)
743 : sizeof (Elf64_External_Dyn);
744 for (bufend = buf + sect_size;
750 Elf32_External_Dyn *dynp = (Elf32_External_Dyn *) buf;
752 current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag,
754 dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr,
759 Elf64_External_Dyn *dynp = (Elf64_External_Dyn *) buf;
761 current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag,
763 dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr,
766 if (current_dyntag == DT_NULL)
769 if (current_dyntag == desired_dyntag)
775 *ptr_addr = base_addr + buf - bufstart;
786 /* Locate the base address of dynamic linker structs for SVR4 elf
789 For SVR4 elf targets the address of the dynamic linker's runtime
790 structure is contained within the dynamic info section in the
791 executable file. The dynamic section is also mapped into the
792 inferior address space. Because the runtime loader fills in the
793 real address before starting the inferior, we have to read in the
794 dynamic info section from the inferior address space.
795 If there are any errors while trying to find the address, we
796 silently return 0, otherwise the found address is returned. */
799 elf_locate_base (void)
801 struct bound_minimal_symbol msymbol;
802 CORE_ADDR dyn_ptr, dyn_ptr_addr;
804 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
805 instead of DT_DEBUG, although they sometimes contain an unused
807 if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr, NULL)
808 || scan_dyntag_auxv (DT_MIPS_RLD_MAP, &dyn_ptr, NULL))
810 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
812 int pbuf_size = TYPE_LENGTH (ptr_type);
814 pbuf = alloca (pbuf_size);
815 /* DT_MIPS_RLD_MAP contains a pointer to the address
816 of the dynamic link structure. */
817 if (target_read_memory (dyn_ptr, pbuf, pbuf_size))
819 return extract_typed_address (pbuf, ptr_type);
822 /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form
823 because of needing to support PIE. DT_MIPS_RLD_MAP will also exist
825 if (scan_dyntag (DT_MIPS_RLD_MAP_REL, exec_bfd, &dyn_ptr, &dyn_ptr_addr)
826 || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL, &dyn_ptr, &dyn_ptr_addr))
828 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
830 int pbuf_size = TYPE_LENGTH (ptr_type);
832 pbuf = alloca (pbuf_size);
833 /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the
834 DT slot to the address of the dynamic link structure. */
835 if (target_read_memory (dyn_ptr + dyn_ptr_addr, pbuf, pbuf_size))
837 return extract_typed_address (pbuf, ptr_type);
841 if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr, NULL)
842 || scan_dyntag_auxv (DT_DEBUG, &dyn_ptr, NULL))
845 /* This may be a static executable. Look for the symbol
846 conventionally named _r_debug, as a last resort. */
847 msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile);
848 if (msymbol.minsym != NULL)
849 return BMSYMBOL_VALUE_ADDRESS (msymbol);
851 /* DT_DEBUG entry not found. */
855 /* Locate the base address of dynamic linker structs.
857 For both the SunOS and SVR4 shared library implementations, if the
858 inferior executable has been linked dynamically, there is a single
859 address somewhere in the inferior's data space which is the key to
860 locating all of the dynamic linker's runtime structures. This
861 address is the value of the debug base symbol. The job of this
862 function is to find and return that address, or to return 0 if there
863 is no such address (the executable is statically linked for example).
865 For SunOS, the job is almost trivial, since the dynamic linker and
866 all of it's structures are statically linked to the executable at
867 link time. Thus the symbol for the address we are looking for has
868 already been added to the minimal symbol table for the executable's
869 objfile at the time the symbol file's symbols were read, and all we
870 have to do is look it up there. Note that we explicitly do NOT want
871 to find the copies in the shared library.
873 The SVR4 version is a bit more complicated because the address
874 is contained somewhere in the dynamic info section. We have to go
875 to a lot more work to discover the address of the debug base symbol.
876 Because of this complexity, we cache the value we find and return that
877 value on subsequent invocations. Note there is no copy in the
878 executable symbol tables. */
881 locate_base (struct svr4_info *info)
883 /* Check to see if we have a currently valid address, and if so, avoid
884 doing all this work again and just return the cached address. If
885 we have no cached address, try to locate it in the dynamic info
886 section for ELF executables. There's no point in doing any of this
887 though if we don't have some link map offsets to work with. */
889 if (info->debug_base == 0 && svr4_have_link_map_offsets ())
890 info->debug_base = elf_locate_base ();
891 return info->debug_base;
894 /* Find the first element in the inferior's dynamic link map, and
895 return its address in the inferior. Return zero if the address
896 could not be determined.
898 FIXME: Perhaps we should validate the info somehow, perhaps by
899 checking r_version for a known version number, or r_state for
903 solib_svr4_r_map (struct svr4_info *info)
905 struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
906 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
911 addr = read_memory_typed_address (info->debug_base + lmo->r_map_offset,
914 CATCH (ex, RETURN_MASK_ERROR)
916 exception_print (gdb_stderr, ex);
923 /* Find r_brk from the inferior's debug base. */
926 solib_svr4_r_brk (struct svr4_info *info)
928 struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
929 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
931 return read_memory_typed_address (info->debug_base + lmo->r_brk_offset,
935 /* Find the link map for the dynamic linker (if it is not in the
936 normal list of loaded shared objects). */
939 solib_svr4_r_ldsomap (struct svr4_info *info)
941 struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
942 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
943 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
944 ULONGEST version = 0;
948 /* Check version, and return zero if `struct r_debug' doesn't have
949 the r_ldsomap member. */
951 = read_memory_unsigned_integer (info->debug_base + lmo->r_version_offset,
952 lmo->r_version_size, byte_order);
954 CATCH (ex, RETURN_MASK_ERROR)
956 exception_print (gdb_stderr, ex);
960 if (version < 2 || lmo->r_ldsomap_offset == -1)
963 return read_memory_typed_address (info->debug_base + lmo->r_ldsomap_offset,
967 /* On Solaris systems with some versions of the dynamic linker,
968 ld.so's l_name pointer points to the SONAME in the string table
969 rather than into writable memory. So that GDB can find shared
970 libraries when loading a core file generated by gcore, ensure that
971 memory areas containing the l_name string are saved in the core
975 svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size)
977 struct svr4_info *info;
979 struct so_list *newobj;
980 struct cleanup *old_chain;
983 info = get_svr4_info ();
985 info->debug_base = 0;
987 if (!info->debug_base)
990 ldsomap = solib_svr4_r_ldsomap (info);
994 newobj = XCNEW (struct so_list);
995 old_chain = make_cleanup (xfree, newobj);
996 newobj->lm_info = lm_info_read (ldsomap);
997 make_cleanup (xfree, newobj->lm_info);
998 name_lm = newobj->lm_info ? newobj->lm_info->l_name : 0;
999 do_cleanups (old_chain);
1001 return (name_lm >= vaddr && name_lm < vaddr + size);
1004 /* Implement the "open_symbol_file_object" target_so_ops method.
1006 If no open symbol file, attempt to locate and open the main symbol
1007 file. On SVR4 systems, this is the first link map entry. If its
1008 name is here, we can open it. Useful when attaching to a process
1009 without first loading its symbol file. */
1012 open_symbol_file_object (void *from_ttyp)
1014 CORE_ADDR lm, l_name;
1017 int from_tty = *(int *)from_ttyp;
1018 struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
1019 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
1020 int l_name_size = TYPE_LENGTH (ptr_type);
1021 gdb_byte *l_name_buf = xmalloc (l_name_size);
1022 struct cleanup *cleanups = make_cleanup (xfree, l_name_buf);
1023 struct svr4_info *info = get_svr4_info ();
1025 if (symfile_objfile)
1026 if (!query (_("Attempt to reload symbols from process? ")))
1028 do_cleanups (cleanups);
1032 /* Always locate the debug struct, in case it has moved. */
1033 info->debug_base = 0;
1034 if (locate_base (info) == 0)
1036 do_cleanups (cleanups);
1037 return 0; /* failed somehow... */
1040 /* First link map member should be the executable. */
1041 lm = solib_svr4_r_map (info);
1044 do_cleanups (cleanups);
1045 return 0; /* failed somehow... */
1048 /* Read address of name from target memory to GDB. */
1049 read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size);
1051 /* Convert the address to host format. */
1052 l_name = extract_typed_address (l_name_buf, ptr_type);
1056 do_cleanups (cleanups);
1057 return 0; /* No filename. */
1060 /* Now fetch the filename from target memory. */
1061 target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode);
1062 make_cleanup (xfree, filename);
1066 warning (_("failed to read exec filename from attached file: %s"),
1067 safe_strerror (errcode));
1068 do_cleanups (cleanups);
1072 /* Have a pathname: read the symbol file. */
1073 symbol_file_add_main (filename, from_tty);
1075 do_cleanups (cleanups);
1079 /* Data exchange structure for the XML parser as returned by
1080 svr4_current_sos_via_xfer_libraries. */
1082 struct svr4_library_list
1084 struct so_list *head, **tailp;
1086 /* Inferior address of struct link_map used for the main executable. It is
1087 NULL if not known. */
1091 /* Implementation for target_so_ops.free_so. */
1094 svr4_free_so (struct so_list *so)
1096 xfree (so->lm_info);
1099 /* Implement target_so_ops.clear_so. */
1102 svr4_clear_so (struct so_list *so)
1104 if (so->lm_info != NULL)
1105 so->lm_info->l_addr_p = 0;
1108 /* Free so_list built so far (called via cleanup). */
1111 svr4_free_library_list (void *p_list)
1113 struct so_list *list = *(struct so_list **) p_list;
1115 while (list != NULL)
1117 struct so_list *next = list->next;
1124 /* Copy library list. */
1126 static struct so_list *
1127 svr4_copy_library_list (struct so_list *src)
1129 struct so_list *dst = NULL;
1130 struct so_list **link = &dst;
1134 struct so_list *newobj;
1136 newobj = xmalloc (sizeof (struct so_list));
1137 memcpy (newobj, src, sizeof (struct so_list));
1139 newobj->lm_info = xmalloc (sizeof (struct lm_info));
1140 memcpy (newobj->lm_info, src->lm_info, sizeof (struct lm_info));
1142 newobj->next = NULL;
1144 link = &newobj->next;
1152 #ifdef HAVE_LIBEXPAT
1154 #include "xml-support.h"
1156 /* Handle the start of a <library> element. Note: new elements are added
1157 at the tail of the list, keeping the list in order. */
1160 library_list_start_library (struct gdb_xml_parser *parser,
1161 const struct gdb_xml_element *element,
1162 void *user_data, VEC(gdb_xml_value_s) *attributes)
1164 struct svr4_library_list *list = user_data;
1165 const char *name = xml_find_attribute (attributes, "name")->value;
1166 ULONGEST *lmp = xml_find_attribute (attributes, "lm")->value;
1167 ULONGEST *l_addrp = xml_find_attribute (attributes, "l_addr")->value;
1168 ULONGEST *l_ldp = xml_find_attribute (attributes, "l_ld")->value;
1169 struct so_list *new_elem;
1171 new_elem = XCNEW (struct so_list);
1172 new_elem->lm_info = XCNEW (struct lm_info);
1173 new_elem->lm_info->lm_addr = *lmp;
1174 new_elem->lm_info->l_addr_inferior = *l_addrp;
1175 new_elem->lm_info->l_ld = *l_ldp;
1177 strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1);
1178 new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0;
1179 strcpy (new_elem->so_original_name, new_elem->so_name);
1181 *list->tailp = new_elem;
1182 list->tailp = &new_elem->next;
1185 /* Handle the start of a <library-list-svr4> element. */
1188 svr4_library_list_start_list (struct gdb_xml_parser *parser,
1189 const struct gdb_xml_element *element,
1190 void *user_data, VEC(gdb_xml_value_s) *attributes)
1192 struct svr4_library_list *list = user_data;
1193 const char *version = xml_find_attribute (attributes, "version")->value;
1194 struct gdb_xml_value *main_lm = xml_find_attribute (attributes, "main-lm");
1196 if (strcmp (version, "1.0") != 0)
1197 gdb_xml_error (parser,
1198 _("SVR4 Library list has unsupported version \"%s\""),
1202 list->main_lm = *(ULONGEST *) main_lm->value;
1205 /* The allowed elements and attributes for an XML library list.
1206 The root element is a <library-list>. */
1208 static const struct gdb_xml_attribute svr4_library_attributes[] =
1210 { "name", GDB_XML_AF_NONE, NULL, NULL },
1211 { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
1212 { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
1213 { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
1214 { NULL, GDB_XML_AF_NONE, NULL, NULL }
1217 static const struct gdb_xml_element svr4_library_list_children[] =
1220 "library", svr4_library_attributes, NULL,
1221 GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
1222 library_list_start_library, NULL
1224 { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
1227 static const struct gdb_xml_attribute svr4_library_list_attributes[] =
1229 { "version", GDB_XML_AF_NONE, NULL, NULL },
1230 { "main-lm", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
1231 { NULL, GDB_XML_AF_NONE, NULL, NULL }
1234 static const struct gdb_xml_element svr4_library_list_elements[] =
1236 { "library-list-svr4", svr4_library_list_attributes, svr4_library_list_children,
1237 GDB_XML_EF_NONE, svr4_library_list_start_list, NULL },
1238 { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
1241 /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if
1243 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1244 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1245 empty, caller is responsible for freeing all its entries. */
1248 svr4_parse_libraries (const char *document, struct svr4_library_list *list)
1250 struct cleanup *back_to = make_cleanup (svr4_free_library_list,
1253 memset (list, 0, sizeof (*list));
1254 list->tailp = &list->head;
1255 if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd",
1256 svr4_library_list_elements, document, list) == 0)
1258 /* Parsed successfully, keep the result. */
1259 discard_cleanups (back_to);
1263 do_cleanups (back_to);
1267 /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet.
1269 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1270 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1271 empty, caller is responsible for freeing all its entries.
1273 Note that ANNEX must be NULL if the remote does not explicitly allow
1274 qXfer:libraries-svr4:read packets with non-empty annexes. Support for
1275 this can be checked using target_augmented_libraries_svr4_read (). */
1278 svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list,
1281 char *svr4_library_document;
1283 struct cleanup *back_to;
1285 gdb_assert (annex == NULL || target_augmented_libraries_svr4_read ());
1287 /* Fetch the list of shared libraries. */
1288 svr4_library_document = target_read_stralloc (¤t_target,
1289 TARGET_OBJECT_LIBRARIES_SVR4,
1291 if (svr4_library_document == NULL)
1294 back_to = make_cleanup (xfree, svr4_library_document);
1295 result = svr4_parse_libraries (svr4_library_document, list);
1296 do_cleanups (back_to);
1304 svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list,
1312 /* If no shared library information is available from the dynamic
1313 linker, build a fallback list from other sources. */
1315 static struct so_list *
1316 svr4_default_sos (void)
1318 struct svr4_info *info = get_svr4_info ();
1319 struct so_list *newobj;
1321 if (!info->debug_loader_offset_p)
1324 newobj = XCNEW (struct so_list);
1326 newobj->lm_info = xzalloc (sizeof (struct lm_info));
1328 /* Nothing will ever check the other fields if we set l_addr_p. */
1329 newobj->lm_info->l_addr = info->debug_loader_offset;
1330 newobj->lm_info->l_addr_p = 1;
1332 strncpy (newobj->so_name, info->debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1);
1333 newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
1334 strcpy (newobj->so_original_name, newobj->so_name);
1339 /* Read the whole inferior libraries chain starting at address LM.
1340 Expect the first entry in the chain's previous entry to be PREV_LM.
1341 Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the
1342 first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according
1343 to it. Returns nonzero upon success. If zero is returned the
1344 entries stored to LINK_PTR_PTR are still valid although they may
1345 represent only part of the inferior library list. */
1348 svr4_read_so_list (CORE_ADDR lm, CORE_ADDR prev_lm,
1349 struct so_list ***link_ptr_ptr, int ignore_first)
1351 CORE_ADDR first_l_name = 0;
1354 for (; lm != 0; prev_lm = lm, lm = next_lm)
1356 struct so_list *newobj;
1357 struct cleanup *old_chain;
1361 newobj = XCNEW (struct so_list);
1362 old_chain = make_cleanup_free_so (newobj);
1364 newobj->lm_info = lm_info_read (lm);
1365 if (newobj->lm_info == NULL)
1367 do_cleanups (old_chain);
1371 next_lm = newobj->lm_info->l_next;
1373 if (newobj->lm_info->l_prev != prev_lm)
1375 warning (_("Corrupted shared library list: %s != %s"),
1376 paddress (target_gdbarch (), prev_lm),
1377 paddress (target_gdbarch (), newobj->lm_info->l_prev));
1378 do_cleanups (old_chain);
1382 /* For SVR4 versions, the first entry in the link map is for the
1383 inferior executable, so we must ignore it. For some versions of
1384 SVR4, it has no name. For others (Solaris 2.3 for example), it
1385 does have a name, so we can no longer use a missing name to
1386 decide when to ignore it. */
1387 if (ignore_first && newobj->lm_info->l_prev == 0)
1389 struct svr4_info *info = get_svr4_info ();
1391 first_l_name = newobj->lm_info->l_name;
1392 info->main_lm_addr = newobj->lm_info->lm_addr;
1393 do_cleanups (old_chain);
1397 /* Extract this shared object's name. */
1398 target_read_string (newobj->lm_info->l_name, &buffer,
1399 SO_NAME_MAX_PATH_SIZE - 1, &errcode);
1402 /* If this entry's l_name address matches that of the
1403 inferior executable, then this is not a normal shared
1404 object, but (most likely) a vDSO. In this case, silently
1405 skip it; otherwise emit a warning. */
1406 if (first_l_name == 0 || newobj->lm_info->l_name != first_l_name)
1407 warning (_("Can't read pathname for load map: %s."),
1408 safe_strerror (errcode));
1409 do_cleanups (old_chain);
1413 strncpy (newobj->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
1414 newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
1415 strcpy (newobj->so_original_name, newobj->so_name);
1418 /* If this entry has no name, or its name matches the name
1419 for the main executable, don't include it in the list. */
1420 if (! newobj->so_name[0] || match_main (newobj->so_name))
1422 do_cleanups (old_chain);
1426 discard_cleanups (old_chain);
1428 **link_ptr_ptr = newobj;
1429 *link_ptr_ptr = &newobj->next;
1435 /* Read the full list of currently loaded shared objects directly
1436 from the inferior, without referring to any libraries read and
1437 stored by the probes interface. Handle special cases relating
1438 to the first elements of the list. */
1440 static struct so_list *
1441 svr4_current_sos_direct (struct svr4_info *info)
1444 struct so_list *head = NULL;
1445 struct so_list **link_ptr = &head;
1446 struct cleanup *back_to;
1448 struct svr4_library_list library_list;
1450 /* Fall back to manual examination of the target if the packet is not
1451 supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp
1452 tests a case where gdbserver cannot find the shared libraries list while
1453 GDB itself is able to find it via SYMFILE_OBJFILE.
1455 Unfortunately statically linked inferiors will also fall back through this
1456 suboptimal code path. */
1458 info->using_xfer = svr4_current_sos_via_xfer_libraries (&library_list,
1460 if (info->using_xfer)
1462 if (library_list.main_lm)
1463 info->main_lm_addr = library_list.main_lm;
1465 return library_list.head ? library_list.head : svr4_default_sos ();
1468 /* Always locate the debug struct, in case it has moved. */
1469 info->debug_base = 0;
1472 /* If we can't find the dynamic linker's base structure, this
1473 must not be a dynamically linked executable. Hmm. */
1474 if (! info->debug_base)
1475 return svr4_default_sos ();
1477 /* Assume that everything is a library if the dynamic loader was loaded
1478 late by a static executable. */
1479 if (exec_bfd && bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL)
1484 back_to = make_cleanup (svr4_free_library_list, &head);
1486 /* Walk the inferior's link map list, and build our list of
1487 `struct so_list' nodes. */
1488 lm = solib_svr4_r_map (info);
1490 svr4_read_so_list (lm, 0, &link_ptr, ignore_first);
1492 /* On Solaris, the dynamic linker is not in the normal list of
1493 shared objects, so make sure we pick it up too. Having
1494 symbol information for the dynamic linker is quite crucial
1495 for skipping dynamic linker resolver code. */
1496 lm = solib_svr4_r_ldsomap (info);
1498 svr4_read_so_list (lm, 0, &link_ptr, 0);
1500 discard_cleanups (back_to);
1503 return svr4_default_sos ();
1508 /* Implement the main part of the "current_sos" target_so_ops
1511 static struct so_list *
1512 svr4_current_sos_1 (void)
1514 struct svr4_info *info = get_svr4_info ();
1516 /* If the solib list has been read and stored by the probes
1517 interface then we return a copy of the stored list. */
1518 if (info->solib_list != NULL)
1519 return svr4_copy_library_list (info->solib_list);
1521 /* Otherwise obtain the solib list directly from the inferior. */
1522 return svr4_current_sos_direct (info);
1525 /* Implement the "current_sos" target_so_ops method. */
1527 static struct so_list *
1528 svr4_current_sos (void)
1530 struct so_list *so_head = svr4_current_sos_1 ();
1531 struct mem_range vsyscall_range;
1533 /* Filter out the vDSO module, if present. Its symbol file would
1534 not be found on disk. The vDSO/vsyscall's OBJFILE is instead
1535 managed by symfile-mem.c:add_vsyscall_page. */
1536 if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range)
1537 && vsyscall_range.length != 0)
1539 struct so_list **sop;
1542 while (*sop != NULL)
1544 struct so_list *so = *sop;
1546 /* We can't simply match the vDSO by starting address alone,
1547 because lm_info->l_addr_inferior (and also l_addr) do not
1548 necessarily represent the real starting address of the
1549 ELF if the vDSO's ELF itself is "prelinked". The l_ld
1550 field (the ".dynamic" section of the shared object)
1551 always points at the absolute/resolved address though.
1552 So check whether that address is inside the vDSO's
1555 E.g., on Linux 3.16 (x86_64) the vDSO is a regular
1556 0-based ELF, and we see:
1559 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000
1560 (gdb) p/x *_r_debug.r_map.l_next
1561 $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...}
1563 And on Linux 2.6.32 (x86_64) we see:
1566 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000
1567 (gdb) p/x *_r_debug.r_map.l_next
1568 $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... }
1570 Dumping that vDSO shows:
1572 (gdb) info proc mappings
1573 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso]
1574 (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000
1575 # readelf -Wa vdso.bin
1577 Entry point address: 0xffffffffff700700
1580 [Nr] Name Type Address Off Size
1581 [ 0] NULL 0000000000000000 000000 000000
1582 [ 1] .hash HASH ffffffffff700120 000120 000038
1583 [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8
1585 [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0
1587 if (address_in_mem_range (so->lm_info->l_ld, &vsyscall_range))
1601 /* Get the address of the link_map for a given OBJFILE. */
1604 svr4_fetch_objfile_link_map (struct objfile *objfile)
1607 struct svr4_info *info = get_svr4_info ();
1609 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1610 if (info->main_lm_addr == 0)
1611 solib_add (NULL, 0, ¤t_target, auto_solib_add);
1613 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1614 if (objfile == symfile_objfile)
1615 return info->main_lm_addr;
1617 /* The other link map addresses may be found by examining the list
1618 of shared libraries. */
1619 for (so = master_so_list (); so; so = so->next)
1620 if (so->objfile == objfile)
1621 return so->lm_info->lm_addr;
1627 /* On some systems, the only way to recognize the link map entry for
1628 the main executable file is by looking at its name. Return
1629 non-zero iff SONAME matches one of the known main executable names. */
1632 match_main (const char *soname)
1634 const char * const *mainp;
1636 for (mainp = main_name_list; *mainp != NULL; mainp++)
1638 if (strcmp (soname, *mainp) == 0)
1645 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1646 SVR4 run time loader. */
1649 svr4_in_dynsym_resolve_code (CORE_ADDR pc)
1651 struct svr4_info *info = get_svr4_info ();
1653 return ((pc >= info->interp_text_sect_low
1654 && pc < info->interp_text_sect_high)
1655 || (pc >= info->interp_plt_sect_low
1656 && pc < info->interp_plt_sect_high)
1657 || in_plt_section (pc)
1658 || in_gnu_ifunc_stub (pc));
1661 /* Given an executable's ABFD and target, compute the entry-point
1665 exec_entry_point (struct bfd *abfd, struct target_ops *targ)
1669 /* KevinB wrote ... for most targets, the address returned by
1670 bfd_get_start_address() is the entry point for the start
1671 function. But, for some targets, bfd_get_start_address() returns
1672 the address of a function descriptor from which the entry point
1673 address may be extracted. This address is extracted by
1674 gdbarch_convert_from_func_ptr_addr(). The method
1675 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1676 function for targets which don't use function descriptors. */
1677 addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
1678 bfd_get_start_address (abfd),
1680 return gdbarch_addr_bits_remove (target_gdbarch (), addr);
1683 /* A probe and its associated action. */
1685 struct probe_and_action
1688 struct probe *probe;
1690 /* The relocated address of the probe. */
1694 enum probe_action action;
1697 /* Returns a hash code for the probe_and_action referenced by p. */
1700 hash_probe_and_action (const void *p)
1702 const struct probe_and_action *pa = p;
1704 return (hashval_t) pa->address;
1707 /* Returns non-zero if the probe_and_actions referenced by p1 and p2
1711 equal_probe_and_action (const void *p1, const void *p2)
1713 const struct probe_and_action *pa1 = p1;
1714 const struct probe_and_action *pa2 = p2;
1716 return pa1->address == pa2->address;
1719 /* Register a solib event probe and its associated action in the
1723 register_solib_event_probe (struct probe *probe, CORE_ADDR address,
1724 enum probe_action action)
1726 struct svr4_info *info = get_svr4_info ();
1727 struct probe_and_action lookup, *pa;
1730 /* Create the probes table, if necessary. */
1731 if (info->probes_table == NULL)
1732 info->probes_table = htab_create_alloc (1, hash_probe_and_action,
1733 equal_probe_and_action,
1734 xfree, xcalloc, xfree);
1736 lookup.probe = probe;
1737 lookup.address = address;
1738 slot = htab_find_slot (info->probes_table, &lookup, INSERT);
1739 gdb_assert (*slot == HTAB_EMPTY_ENTRY);
1741 pa = XCNEW (struct probe_and_action);
1743 pa->address = address;
1744 pa->action = action;
1749 /* Get the solib event probe at the specified location, and the
1750 action associated with it. Returns NULL if no solib event probe
1753 static struct probe_and_action *
1754 solib_event_probe_at (struct svr4_info *info, CORE_ADDR address)
1756 struct probe_and_action lookup;
1759 lookup.address = address;
1760 slot = htab_find_slot (info->probes_table, &lookup, NO_INSERT);
1765 return (struct probe_and_action *) *slot;
1768 /* Decide what action to take when the specified solib event probe is
1771 static enum probe_action
1772 solib_event_probe_action (struct probe_and_action *pa)
1774 enum probe_action action;
1775 unsigned probe_argc;
1776 struct frame_info *frame = get_current_frame ();
1778 action = pa->action;
1779 if (action == DO_NOTHING || action == PROBES_INTERFACE_FAILED)
1782 gdb_assert (action == FULL_RELOAD || action == UPDATE_OR_RELOAD);
1784 /* Check that an appropriate number of arguments has been supplied.
1786 arg0: Lmid_t lmid (mandatory)
1787 arg1: struct r_debug *debug_base (mandatory)
1788 arg2: struct link_map *new (optional, for incremental updates) */
1789 probe_argc = get_probe_argument_count (pa->probe, frame);
1790 if (probe_argc == 2)
1791 action = FULL_RELOAD;
1792 else if (probe_argc < 2)
1793 action = PROBES_INTERFACE_FAILED;
1798 /* Populate the shared object list by reading the entire list of
1799 shared objects from the inferior. Handle special cases relating
1800 to the first elements of the list. Returns nonzero on success. */
1803 solist_update_full (struct svr4_info *info)
1805 free_solib_list (info);
1806 info->solib_list = svr4_current_sos_direct (info);
1811 /* Update the shared object list starting from the link-map entry
1812 passed by the linker in the probe's third argument. Returns
1813 nonzero if the list was successfully updated, or zero to indicate
1817 solist_update_incremental (struct svr4_info *info, CORE_ADDR lm)
1819 struct so_list *tail;
1822 /* svr4_current_sos_direct contains logic to handle a number of
1823 special cases relating to the first elements of the list. To
1824 avoid duplicating this logic we defer to solist_update_full
1825 if the list is empty. */
1826 if (info->solib_list == NULL)
1829 /* Fall back to a full update if we are using a remote target
1830 that does not support incremental transfers. */
1831 if (info->using_xfer && !target_augmented_libraries_svr4_read ())
1834 /* Walk to the end of the list. */
1835 for (tail = info->solib_list; tail->next != NULL; tail = tail->next)
1837 prev_lm = tail->lm_info->lm_addr;
1839 /* Read the new objects. */
1840 if (info->using_xfer)
1842 struct svr4_library_list library_list;
1845 xsnprintf (annex, sizeof (annex), "start=%s;prev=%s",
1846 phex_nz (lm, sizeof (lm)),
1847 phex_nz (prev_lm, sizeof (prev_lm)));
1848 if (!svr4_current_sos_via_xfer_libraries (&library_list, annex))
1851 tail->next = library_list.head;
1855 struct so_list **link = &tail->next;
1857 /* IGNORE_FIRST may safely be set to zero here because the
1858 above check and deferral to solist_update_full ensures
1859 that this call to svr4_read_so_list will never see the
1861 if (!svr4_read_so_list (lm, prev_lm, &link, 0))
1868 /* Disable the probes-based linker interface and revert to the
1869 original interface. We don't reset the breakpoints as the
1870 ones set up for the probes-based interface are adequate. */
1873 disable_probes_interface_cleanup (void *arg)
1875 struct svr4_info *info = get_svr4_info ();
1877 warning (_("Probes-based dynamic linker interface failed.\n"
1878 "Reverting to original interface.\n"));
1880 free_probes_table (info);
1881 free_solib_list (info);
1884 /* Update the solib list as appropriate when using the
1885 probes-based linker interface. Do nothing if using the
1886 standard interface. */
1889 svr4_handle_solib_event (void)
1891 struct svr4_info *info = get_svr4_info ();
1892 struct probe_and_action *pa;
1893 enum probe_action action;
1894 struct cleanup *old_chain, *usm_chain;
1896 CORE_ADDR pc, debug_base, lm = 0;
1898 struct frame_info *frame = get_current_frame ();
1900 /* Do nothing if not using the probes interface. */
1901 if (info->probes_table == NULL)
1904 /* If anything goes wrong we revert to the original linker
1906 old_chain = make_cleanup (disable_probes_interface_cleanup, NULL);
1908 pc = regcache_read_pc (get_current_regcache ());
1909 pa = solib_event_probe_at (info, pc);
1912 do_cleanups (old_chain);
1916 action = solib_event_probe_action (pa);
1917 if (action == PROBES_INTERFACE_FAILED)
1919 do_cleanups (old_chain);
1923 if (action == DO_NOTHING)
1925 discard_cleanups (old_chain);
1929 /* evaluate_probe_argument looks up symbols in the dynamic linker
1930 using find_pc_section. find_pc_section is accelerated by a cache
1931 called the section map. The section map is invalidated every
1932 time a shared library is loaded or unloaded, and if the inferior
1933 is generating a lot of shared library events then the section map
1934 will be updated every time svr4_handle_solib_event is called.
1935 We called find_pc_section in svr4_create_solib_event_breakpoints,
1936 so we can guarantee that the dynamic linker's sections are in the
1937 section map. We can therefore inhibit section map updates across
1938 these calls to evaluate_probe_argument and save a lot of time. */
1939 inhibit_section_map_updates (current_program_space);
1940 usm_chain = make_cleanup (resume_section_map_updates_cleanup,
1941 current_program_space);
1943 val = evaluate_probe_argument (pa->probe, 1, frame);
1946 do_cleanups (old_chain);
1950 debug_base = value_as_address (val);
1951 if (debug_base == 0)
1953 do_cleanups (old_chain);
1957 /* Always locate the debug struct, in case it moved. */
1958 info->debug_base = 0;
1959 if (locate_base (info) == 0)
1961 do_cleanups (old_chain);
1965 /* GDB does not currently support libraries loaded via dlmopen
1966 into namespaces other than the initial one. We must ignore
1967 any namespace other than the initial namespace here until
1968 support for this is added to GDB. */
1969 if (debug_base != info->debug_base)
1970 action = DO_NOTHING;
1972 if (action == UPDATE_OR_RELOAD)
1974 val = evaluate_probe_argument (pa->probe, 2, frame);
1976 lm = value_as_address (val);
1979 action = FULL_RELOAD;
1982 /* Resume section map updates. */
1983 do_cleanups (usm_chain);
1985 if (action == UPDATE_OR_RELOAD)
1987 if (!solist_update_incremental (info, lm))
1988 action = FULL_RELOAD;
1991 if (action == FULL_RELOAD)
1993 if (!solist_update_full (info))
1995 do_cleanups (old_chain);
2000 discard_cleanups (old_chain);
2003 /* Helper function for svr4_update_solib_event_breakpoints. */
2006 svr4_update_solib_event_breakpoint (struct breakpoint *b, void *arg)
2008 struct bp_location *loc;
2010 if (b->type != bp_shlib_event)
2012 /* Continue iterating. */
2016 for (loc = b->loc; loc != NULL; loc = loc->next)
2018 struct svr4_info *info;
2019 struct probe_and_action *pa;
2021 info = program_space_data (loc->pspace, solib_svr4_pspace_data);
2022 if (info == NULL || info->probes_table == NULL)
2025 pa = solib_event_probe_at (info, loc->address);
2029 if (pa->action == DO_NOTHING)
2031 if (b->enable_state == bp_disabled && stop_on_solib_events)
2032 enable_breakpoint (b);
2033 else if (b->enable_state == bp_enabled && !stop_on_solib_events)
2034 disable_breakpoint (b);
2040 /* Continue iterating. */
2044 /* Enable or disable optional solib event breakpoints as appropriate.
2045 Called whenever stop_on_solib_events is changed. */
2048 svr4_update_solib_event_breakpoints (void)
2050 iterate_over_breakpoints (svr4_update_solib_event_breakpoint, NULL);
2053 /* Create and register solib event breakpoints. PROBES is an array
2054 of NUM_PROBES elements, each of which is vector of probes. A
2055 solib event breakpoint will be created and registered for each
2059 svr4_create_probe_breakpoints (struct gdbarch *gdbarch,
2060 VEC (probe_p) **probes,
2061 struct objfile *objfile)
2065 for (i = 0; i < NUM_PROBES; i++)
2067 enum probe_action action = probe_info[i].action;
2068 struct probe *probe;
2072 VEC_iterate (probe_p, probes[i], ix, probe);
2075 CORE_ADDR address = get_probe_address (probe, objfile);
2077 create_solib_event_breakpoint (gdbarch, address);
2078 register_solib_event_probe (probe, address, action);
2082 svr4_update_solib_event_breakpoints ();
2085 /* Both the SunOS and the SVR4 dynamic linkers call a marker function
2086 before and after mapping and unmapping shared libraries. The sole
2087 purpose of this method is to allow debuggers to set a breakpoint so
2088 they can track these changes.
2090 Some versions of the glibc dynamic linker contain named probes
2091 to allow more fine grained stopping. Given the address of the
2092 original marker function, this function attempts to find these
2093 probes, and if found, sets breakpoints on those instead. If the
2094 probes aren't found, a single breakpoint is set on the original
2098 svr4_create_solib_event_breakpoints (struct gdbarch *gdbarch,
2101 struct obj_section *os;
2103 os = find_pc_section (address);
2108 for (with_prefix = 0; with_prefix <= 1; with_prefix++)
2110 VEC (probe_p) *probes[NUM_PROBES];
2111 int all_probes_found = 1;
2112 int checked_can_use_probe_arguments = 0;
2115 memset (probes, 0, sizeof (probes));
2116 for (i = 0; i < NUM_PROBES; i++)
2118 const char *name = probe_info[i].name;
2122 /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4
2123 shipped with an early version of the probes code in
2124 which the probes' names were prefixed with "rtld_"
2125 and the "map_failed" probe did not exist. The
2126 locations of the probes are otherwise the same, so
2127 we check for probes with prefixed names if probes
2128 with unprefixed names are not present. */
2131 xsnprintf (buf, sizeof (buf), "rtld_%s", name);
2135 probes[i] = find_probes_in_objfile (os->objfile, "rtld", name);
2137 /* The "map_failed" probe did not exist in early
2138 versions of the probes code in which the probes'
2139 names were prefixed with "rtld_". */
2140 if (strcmp (name, "rtld_map_failed") == 0)
2143 if (VEC_empty (probe_p, probes[i]))
2145 all_probes_found = 0;
2149 /* Ensure probe arguments can be evaluated. */
2150 if (!checked_can_use_probe_arguments)
2152 p = VEC_index (probe_p, probes[i], 0);
2153 if (!can_evaluate_probe_arguments (p))
2155 all_probes_found = 0;
2158 checked_can_use_probe_arguments = 1;
2162 if (all_probes_found)
2163 svr4_create_probe_breakpoints (gdbarch, probes, os->objfile);
2165 for (i = 0; i < NUM_PROBES; i++)
2166 VEC_free (probe_p, probes[i]);
2168 if (all_probes_found)
2173 create_solib_event_breakpoint (gdbarch, address);
2176 /* Helper function for gdb_bfd_lookup_symbol. */
2179 cmp_name_and_sec_flags (asymbol *sym, void *data)
2181 return (strcmp (sym->name, (const char *) data) == 0
2182 && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0);
2184 /* Arrange for dynamic linker to hit breakpoint.
2186 Both the SunOS and the SVR4 dynamic linkers have, as part of their
2187 debugger interface, support for arranging for the inferior to hit
2188 a breakpoint after mapping in the shared libraries. This function
2189 enables that breakpoint.
2191 For SunOS, there is a special flag location (in_debugger) which we
2192 set to 1. When the dynamic linker sees this flag set, it will set
2193 a breakpoint at a location known only to itself, after saving the
2194 original contents of that place and the breakpoint address itself,
2195 in it's own internal structures. When we resume the inferior, it
2196 will eventually take a SIGTRAP when it runs into the breakpoint.
2197 We handle this (in a different place) by restoring the contents of
2198 the breakpointed location (which is only known after it stops),
2199 chasing around to locate the shared libraries that have been
2200 loaded, then resuming.
2202 For SVR4, the debugger interface structure contains a member (r_brk)
2203 which is statically initialized at the time the shared library is
2204 built, to the offset of a function (_r_debug_state) which is guaran-
2205 teed to be called once before mapping in a library, and again when
2206 the mapping is complete. At the time we are examining this member,
2207 it contains only the unrelocated offset of the function, so we have
2208 to do our own relocation. Later, when the dynamic linker actually
2209 runs, it relocates r_brk to be the actual address of _r_debug_state().
2211 The debugger interface structure also contains an enumeration which
2212 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
2213 depending upon whether or not the library is being mapped or unmapped,
2214 and then set to RT_CONSISTENT after the library is mapped/unmapped. */
2217 enable_break (struct svr4_info *info, int from_tty)
2219 struct bound_minimal_symbol msymbol;
2220 const char * const *bkpt_namep;
2221 asection *interp_sect;
2225 info->interp_text_sect_low = info->interp_text_sect_high = 0;
2226 info->interp_plt_sect_low = info->interp_plt_sect_high = 0;
2228 /* If we already have a shared library list in the target, and
2229 r_debug contains r_brk, set the breakpoint there - this should
2230 mean r_brk has already been relocated. Assume the dynamic linker
2231 is the object containing r_brk. */
2233 solib_add (NULL, from_tty, ¤t_target, auto_solib_add);
2235 if (info->debug_base && solib_svr4_r_map (info) != 0)
2236 sym_addr = solib_svr4_r_brk (info);
2240 struct obj_section *os;
2242 sym_addr = gdbarch_addr_bits_remove
2243 (target_gdbarch (), gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2247 /* On at least some versions of Solaris there's a dynamic relocation
2248 on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
2249 we get control before the dynamic linker has self-relocated.
2250 Check if SYM_ADDR is in a known section, if it is assume we can
2251 trust its value. This is just a heuristic though, it could go away
2252 or be replaced if it's getting in the way.
2254 On ARM we need to know whether the ISA of rtld_db_dlactivity (or
2255 however it's spelled in your particular system) is ARM or Thumb.
2256 That knowledge is encoded in the address, if it's Thumb the low bit
2257 is 1. However, we've stripped that info above and it's not clear
2258 what all the consequences are of passing a non-addr_bits_remove'd
2259 address to svr4_create_solib_event_breakpoints. The call to
2260 find_pc_section verifies we know about the address and have some
2261 hope of computing the right kind of breakpoint to use (via
2262 symbol info). It does mean that GDB needs to be pointed at a
2263 non-stripped version of the dynamic linker in order to obtain
2264 information it already knows about. Sigh. */
2266 os = find_pc_section (sym_addr);
2269 /* Record the relocated start and end address of the dynamic linker
2270 text and plt section for svr4_in_dynsym_resolve_code. */
2272 CORE_ADDR load_addr;
2274 tmp_bfd = os->objfile->obfd;
2275 load_addr = ANOFFSET (os->objfile->section_offsets,
2276 SECT_OFF_TEXT (os->objfile));
2278 interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
2281 info->interp_text_sect_low =
2282 bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
2283 info->interp_text_sect_high =
2284 info->interp_text_sect_low
2285 + bfd_section_size (tmp_bfd, interp_sect);
2287 interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
2290 info->interp_plt_sect_low =
2291 bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
2292 info->interp_plt_sect_high =
2293 info->interp_plt_sect_low
2294 + bfd_section_size (tmp_bfd, interp_sect);
2297 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
2302 /* Find the program interpreter; if not found, warn the user and drop
2303 into the old breakpoint at symbol code. */
2304 interp_name = find_program_interpreter ();
2307 CORE_ADDR load_addr = 0;
2308 int load_addr_found = 0;
2309 int loader_found_in_list = 0;
2311 bfd *tmp_bfd = NULL;
2312 struct target_ops *tmp_bfd_target;
2316 /* Now we need to figure out where the dynamic linker was
2317 loaded so that we can load its symbols and place a breakpoint
2318 in the dynamic linker itself.
2320 This address is stored on the stack. However, I've been unable
2321 to find any magic formula to find it for Solaris (appears to
2322 be trivial on GNU/Linux). Therefore, we have to try an alternate
2323 mechanism to find the dynamic linker's base address. */
2327 tmp_bfd = solib_bfd_open (interp_name);
2329 CATCH (ex, RETURN_MASK_ALL)
2334 if (tmp_bfd == NULL)
2335 goto bkpt_at_symbol;
2337 /* Now convert the TMP_BFD into a target. That way target, as
2338 well as BFD operations can be used. */
2339 tmp_bfd_target = target_bfd_reopen (tmp_bfd);
2340 /* target_bfd_reopen acquired its own reference, so we can
2341 release ours now. */
2342 gdb_bfd_unref (tmp_bfd);
2344 /* On a running target, we can get the dynamic linker's base
2345 address from the shared library table. */
2346 so = master_so_list ();
2349 if (svr4_same_1 (interp_name, so->so_original_name))
2351 load_addr_found = 1;
2352 loader_found_in_list = 1;
2353 load_addr = lm_addr_check (so, tmp_bfd);
2359 /* If we were not able to find the base address of the loader
2360 from our so_list, then try using the AT_BASE auxilliary entry. */
2361 if (!load_addr_found)
2362 if (target_auxv_search (¤t_target, AT_BASE, &load_addr) > 0)
2364 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
2366 /* Ensure LOAD_ADDR has proper sign in its possible upper bits so
2367 that `+ load_addr' will overflow CORE_ADDR width not creating
2368 invalid addresses like 0x101234567 for 32bit inferiors on 64bit
2371 if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))
2373 CORE_ADDR space_size = (CORE_ADDR) 1 << addr_bit;
2374 CORE_ADDR tmp_entry_point = exec_entry_point (tmp_bfd,
2377 gdb_assert (load_addr < space_size);
2379 /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked
2380 64bit ld.so with 32bit executable, it should not happen. */
2382 if (tmp_entry_point < space_size
2383 && tmp_entry_point + load_addr >= space_size)
2384 load_addr -= space_size;
2387 load_addr_found = 1;
2390 /* Otherwise we find the dynamic linker's base address by examining
2391 the current pc (which should point at the entry point for the
2392 dynamic linker) and subtracting the offset of the entry point.
2394 This is more fragile than the previous approaches, but is a good
2395 fallback method because it has actually been working well in
2397 if (!load_addr_found)
2399 struct regcache *regcache
2400 = get_thread_arch_regcache (inferior_ptid, target_gdbarch ());
2402 load_addr = (regcache_read_pc (regcache)
2403 - exec_entry_point (tmp_bfd, tmp_bfd_target));
2406 if (!loader_found_in_list)
2408 info->debug_loader_name = xstrdup (interp_name);
2409 info->debug_loader_offset_p = 1;
2410 info->debug_loader_offset = load_addr;
2411 solib_add (NULL, from_tty, ¤t_target, auto_solib_add);
2414 /* Record the relocated start and end address of the dynamic linker
2415 text and plt section for svr4_in_dynsym_resolve_code. */
2416 interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
2419 info->interp_text_sect_low =
2420 bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
2421 info->interp_text_sect_high =
2422 info->interp_text_sect_low
2423 + bfd_section_size (tmp_bfd, interp_sect);
2425 interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
2428 info->interp_plt_sect_low =
2429 bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
2430 info->interp_plt_sect_high =
2431 info->interp_plt_sect_low
2432 + bfd_section_size (tmp_bfd, interp_sect);
2435 /* Now try to set a breakpoint in the dynamic linker. */
2436 for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
2438 sym_addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name_and_sec_flags,
2439 (void *) *bkpt_namep);
2445 /* Convert 'sym_addr' from a function pointer to an address.
2446 Because we pass tmp_bfd_target instead of the current
2447 target, this will always produce an unrelocated value. */
2448 sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2452 /* We're done with both the temporary bfd and target. Closing
2453 the target closes the underlying bfd, because it holds the
2454 only remaining reference. */
2455 target_close (tmp_bfd_target);
2459 svr4_create_solib_event_breakpoints (target_gdbarch (),
2460 load_addr + sym_addr);
2461 xfree (interp_name);
2465 /* For whatever reason we couldn't set a breakpoint in the dynamic
2466 linker. Warn and drop into the old code. */
2468 xfree (interp_name);
2469 warning (_("Unable to find dynamic linker breakpoint function.\n"
2470 "GDB will be unable to debug shared library initializers\n"
2471 "and track explicitly loaded dynamic code."));
2474 /* Scan through the lists of symbols, trying to look up the symbol and
2475 set a breakpoint there. Terminate loop when we/if we succeed. */
2477 for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
2479 msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
2480 if ((msymbol.minsym != NULL)
2481 && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0))
2483 sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
2484 sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2487 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
2492 if (interp_name != NULL && !current_inferior ()->attach_flag)
2494 for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
2496 msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
2497 if ((msymbol.minsym != NULL)
2498 && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0))
2500 sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
2501 sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2504 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
2512 /* Implement the "special_symbol_handling" target_so_ops method. */
2515 svr4_special_symbol_handling (void)
2517 /* Nothing to do. */
2520 /* Read the ELF program headers from ABFD. Return the contents and
2521 set *PHDRS_SIZE to the size of the program headers. */
2524 read_program_headers_from_bfd (bfd *abfd, int *phdrs_size)
2526 Elf_Internal_Ehdr *ehdr;
2529 ehdr = elf_elfheader (abfd);
2531 *phdrs_size = ehdr->e_phnum * ehdr->e_phentsize;
2532 if (*phdrs_size == 0)
2535 buf = xmalloc (*phdrs_size);
2536 if (bfd_seek (abfd, ehdr->e_phoff, SEEK_SET) != 0
2537 || bfd_bread (buf, *phdrs_size, abfd) != *phdrs_size)
2546 /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior
2547 exec_bfd. Otherwise return 0.
2549 We relocate all of the sections by the same amount. This
2550 behavior is mandated by recent editions of the System V ABI.
2551 According to the System V Application Binary Interface,
2552 Edition 4.1, page 5-5:
2554 ... Though the system chooses virtual addresses for
2555 individual processes, it maintains the segments' relative
2556 positions. Because position-independent code uses relative
2557 addressesing between segments, the difference between
2558 virtual addresses in memory must match the difference
2559 between virtual addresses in the file. The difference
2560 between the virtual address of any segment in memory and
2561 the corresponding virtual address in the file is thus a
2562 single constant value for any one executable or shared
2563 object in a given process. This difference is the base
2564 address. One use of the base address is to relocate the
2565 memory image of the program during dynamic linking.
2567 The same language also appears in Edition 4.0 of the System V
2568 ABI and is left unspecified in some of the earlier editions.
2570 Decide if the objfile needs to be relocated. As indicated above, we will
2571 only be here when execution is stopped. But during attachment PC can be at
2572 arbitrary address therefore regcache_read_pc can be misleading (contrary to
2573 the auxv AT_ENTRY value). Moreover for executable with interpreter section
2574 regcache_read_pc would point to the interpreter and not the main executable.
2576 So, to summarize, relocations are necessary when the start address obtained
2577 from the executable is different from the address in auxv AT_ENTRY entry.
2579 [ The astute reader will note that we also test to make sure that
2580 the executable in question has the DYNAMIC flag set. It is my
2581 opinion that this test is unnecessary (undesirable even). It
2582 was added to avoid inadvertent relocation of an executable
2583 whose e_type member in the ELF header is not ET_DYN. There may
2584 be a time in the future when it is desirable to do relocations
2585 on other types of files as well in which case this condition
2586 should either be removed or modified to accomodate the new file
2587 type. - Kevin, Nov 2000. ] */
2590 svr4_exec_displacement (CORE_ADDR *displacementp)
2592 /* ENTRY_POINT is a possible function descriptor - before
2593 a call to gdbarch_convert_from_func_ptr_addr. */
2594 CORE_ADDR entry_point, exec_displacement;
2596 if (exec_bfd == NULL)
2599 /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries
2600 being executed themselves and PIE (Position Independent Executable)
2601 executables are ET_DYN. */
2603 if ((bfd_get_file_flags (exec_bfd) & DYNAMIC) == 0)
2606 if (target_auxv_search (¤t_target, AT_ENTRY, &entry_point) <= 0)
2609 exec_displacement = entry_point - bfd_get_start_address (exec_bfd);
2611 /* Verify the EXEC_DISPLACEMENT candidate complies with the required page
2612 alignment. It is cheaper than the program headers comparison below. */
2614 if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
2616 const struct elf_backend_data *elf = get_elf_backend_data (exec_bfd);
2618 /* p_align of PT_LOAD segments does not specify any alignment but
2619 only congruency of addresses:
2620 p_offset % p_align == p_vaddr % p_align
2621 Kernel is free to load the executable with lower alignment. */
2623 if ((exec_displacement & (elf->minpagesize - 1)) != 0)
2627 /* Verify that the auxilliary vector describes the same file as exec_bfd, by
2628 comparing their program headers. If the program headers in the auxilliary
2629 vector do not match the program headers in the executable, then we are
2630 looking at a different file than the one used by the kernel - for
2631 instance, "gdb program" connected to "gdbserver :PORT ld.so program". */
2633 if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
2635 /* Be optimistic and clear OK only if GDB was able to verify the headers
2636 really do not match. */
2637 int phdrs_size, phdrs2_size, ok = 1;
2638 gdb_byte *buf, *buf2;
2641 buf = read_program_header (-1, &phdrs_size, &arch_size, NULL);
2642 buf2 = read_program_headers_from_bfd (exec_bfd, &phdrs2_size);
2643 if (buf != NULL && buf2 != NULL)
2645 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
2647 /* We are dealing with three different addresses. EXEC_BFD
2648 represents current address in on-disk file. target memory content
2649 may be different from EXEC_BFD as the file may have been prelinked
2650 to a different address after the executable has been loaded.
2651 Moreover the address of placement in target memory can be
2652 different from what the program headers in target memory say -
2653 this is the goal of PIE.
2655 Detected DISPLACEMENT covers both the offsets of PIE placement and
2656 possible new prelink performed after start of the program. Here
2657 relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
2658 content offset for the verification purpose. */
2660 if (phdrs_size != phdrs2_size
2661 || bfd_get_arch_size (exec_bfd) != arch_size)
2663 else if (arch_size == 32
2664 && phdrs_size >= sizeof (Elf32_External_Phdr)
2665 && phdrs_size % sizeof (Elf32_External_Phdr) == 0)
2667 Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header;
2668 Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr;
2669 CORE_ADDR displacement = 0;
2672 /* DISPLACEMENT could be found more easily by the difference of
2673 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2674 already have enough information to compute that displacement
2675 with what we've read. */
2677 for (i = 0; i < ehdr2->e_phnum; i++)
2678 if (phdr2[i].p_type == PT_LOAD)
2680 Elf32_External_Phdr *phdrp;
2681 gdb_byte *buf_vaddr_p, *buf_paddr_p;
2682 CORE_ADDR vaddr, paddr;
2683 CORE_ADDR displacement_vaddr = 0;
2684 CORE_ADDR displacement_paddr = 0;
2686 phdrp = &((Elf32_External_Phdr *) buf)[i];
2687 buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
2688 buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
2690 vaddr = extract_unsigned_integer (buf_vaddr_p, 4,
2692 displacement_vaddr = vaddr - phdr2[i].p_vaddr;
2694 paddr = extract_unsigned_integer (buf_paddr_p, 4,
2696 displacement_paddr = paddr - phdr2[i].p_paddr;
2698 if (displacement_vaddr == displacement_paddr)
2699 displacement = displacement_vaddr;
2704 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2706 for (i = 0; i < phdrs_size / sizeof (Elf32_External_Phdr); i++)
2708 Elf32_External_Phdr *phdrp;
2709 Elf32_External_Phdr *phdr2p;
2710 gdb_byte *buf_vaddr_p, *buf_paddr_p;
2711 CORE_ADDR vaddr, paddr;
2712 asection *plt2_asect;
2714 phdrp = &((Elf32_External_Phdr *) buf)[i];
2715 buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
2716 buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
2717 phdr2p = &((Elf32_External_Phdr *) buf2)[i];
2719 /* PT_GNU_STACK is an exception by being never relocated by
2720 prelink as its addresses are always zero. */
2722 if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
2725 /* Check also other adjustment combinations - PR 11786. */
2727 vaddr = extract_unsigned_integer (buf_vaddr_p, 4,
2729 vaddr -= displacement;
2730 store_unsigned_integer (buf_vaddr_p, 4, byte_order, vaddr);
2732 paddr = extract_unsigned_integer (buf_paddr_p, 4,
2734 paddr -= displacement;
2735 store_unsigned_integer (buf_paddr_p, 4, byte_order, paddr);
2737 if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
2740 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2741 CentOS-5 has problems with filesz, memsz as well.
2743 if (phdr2[i].p_type == PT_GNU_RELRO)
2745 Elf32_External_Phdr tmp_phdr = *phdrp;
2746 Elf32_External_Phdr tmp_phdr2 = *phdr2p;
2748 memset (tmp_phdr.p_filesz, 0, 4);
2749 memset (tmp_phdr.p_memsz, 0, 4);
2750 memset (tmp_phdr.p_flags, 0, 4);
2751 memset (tmp_phdr.p_align, 0, 4);
2752 memset (tmp_phdr2.p_filesz, 0, 4);
2753 memset (tmp_phdr2.p_memsz, 0, 4);
2754 memset (tmp_phdr2.p_flags, 0, 4);
2755 memset (tmp_phdr2.p_align, 0, 4);
2757 if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr))
2762 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2763 plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt");
2767 gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz;
2770 content2 = (bfd_get_section_flags (exec_bfd, plt2_asect)
2771 & SEC_HAS_CONTENTS) != 0;
2773 filesz = extract_unsigned_integer (buf_filesz_p, 4,
2776 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2777 FILESZ is from the in-memory image. */
2779 filesz += bfd_get_section_size (plt2_asect);
2781 filesz -= bfd_get_section_size (plt2_asect);
2783 store_unsigned_integer (buf_filesz_p, 4, byte_order,
2786 if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
2794 else if (arch_size == 64
2795 && phdrs_size >= sizeof (Elf64_External_Phdr)
2796 && phdrs_size % sizeof (Elf64_External_Phdr) == 0)
2798 Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header;
2799 Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr;
2800 CORE_ADDR displacement = 0;
2803 /* DISPLACEMENT could be found more easily by the difference of
2804 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2805 already have enough information to compute that displacement
2806 with what we've read. */
2808 for (i = 0; i < ehdr2->e_phnum; i++)
2809 if (phdr2[i].p_type == PT_LOAD)
2811 Elf64_External_Phdr *phdrp;
2812 gdb_byte *buf_vaddr_p, *buf_paddr_p;
2813 CORE_ADDR vaddr, paddr;
2814 CORE_ADDR displacement_vaddr = 0;
2815 CORE_ADDR displacement_paddr = 0;
2817 phdrp = &((Elf64_External_Phdr *) buf)[i];
2818 buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
2819 buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
2821 vaddr = extract_unsigned_integer (buf_vaddr_p, 8,
2823 displacement_vaddr = vaddr - phdr2[i].p_vaddr;
2825 paddr = extract_unsigned_integer (buf_paddr_p, 8,
2827 displacement_paddr = paddr - phdr2[i].p_paddr;
2829 if (displacement_vaddr == displacement_paddr)
2830 displacement = displacement_vaddr;
2835 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2837 for (i = 0; i < phdrs_size / sizeof (Elf64_External_Phdr); i++)
2839 Elf64_External_Phdr *phdrp;
2840 Elf64_External_Phdr *phdr2p;
2841 gdb_byte *buf_vaddr_p, *buf_paddr_p;
2842 CORE_ADDR vaddr, paddr;
2843 asection *plt2_asect;
2845 phdrp = &((Elf64_External_Phdr *) buf)[i];
2846 buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr;
2847 buf_paddr_p = (gdb_byte *) &phdrp->p_paddr;
2848 phdr2p = &((Elf64_External_Phdr *) buf2)[i];
2850 /* PT_GNU_STACK is an exception by being never relocated by
2851 prelink as its addresses are always zero. */
2853 if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
2856 /* Check also other adjustment combinations - PR 11786. */
2858 vaddr = extract_unsigned_integer (buf_vaddr_p, 8,
2860 vaddr -= displacement;
2861 store_unsigned_integer (buf_vaddr_p, 8, byte_order, vaddr);
2863 paddr = extract_unsigned_integer (buf_paddr_p, 8,
2865 paddr -= displacement;
2866 store_unsigned_integer (buf_paddr_p, 8, byte_order, paddr);
2868 if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
2871 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2872 CentOS-5 has problems with filesz, memsz as well.
2874 if (phdr2[i].p_type == PT_GNU_RELRO)
2876 Elf64_External_Phdr tmp_phdr = *phdrp;
2877 Elf64_External_Phdr tmp_phdr2 = *phdr2p;
2879 memset (tmp_phdr.p_filesz, 0, 8);
2880 memset (tmp_phdr.p_memsz, 0, 8);
2881 memset (tmp_phdr.p_flags, 0, 4);
2882 memset (tmp_phdr.p_align, 0, 8);
2883 memset (tmp_phdr2.p_filesz, 0, 8);
2884 memset (tmp_phdr2.p_memsz, 0, 8);
2885 memset (tmp_phdr2.p_flags, 0, 4);
2886 memset (tmp_phdr2.p_align, 0, 8);
2888 if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr))
2893 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2894 plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt");
2898 gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz;
2901 content2 = (bfd_get_section_flags (exec_bfd, plt2_asect)
2902 & SEC_HAS_CONTENTS) != 0;
2904 filesz = extract_unsigned_integer (buf_filesz_p, 8,
2907 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2908 FILESZ is from the in-memory image. */
2910 filesz += bfd_get_section_size (plt2_asect);
2912 filesz -= bfd_get_section_size (plt2_asect);
2914 store_unsigned_integer (buf_filesz_p, 8, byte_order,
2917 if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
2938 /* It can be printed repeatedly as there is no easy way to check
2939 the executable symbols/file has been already relocated to
2942 printf_unfiltered (_("Using PIE (Position Independent Executable) "
2943 "displacement %s for \"%s\".\n"),
2944 paddress (target_gdbarch (), exec_displacement),
2945 bfd_get_filename (exec_bfd));
2948 *displacementp = exec_displacement;
2952 /* Relocate the main executable. This function should be called upon
2953 stopping the inferior process at the entry point to the program.
2954 The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
2955 different, the main executable is relocated by the proper amount. */
2958 svr4_relocate_main_executable (void)
2960 CORE_ADDR displacement;
2962 /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS
2963 probably contains the offsets computed using the PIE displacement
2964 from the previous run, which of course are irrelevant for this run.
2965 So we need to determine the new PIE displacement and recompute the
2966 section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS
2967 already contains pre-computed offsets.
2969 If we cannot compute the PIE displacement, either:
2971 - The executable is not PIE.
2973 - SYMFILE_OBJFILE does not match the executable started in the target.
2974 This can happen for main executable symbols loaded at the host while
2975 `ld.so --ld-args main-executable' is loaded in the target.
2977 Then we leave the section offsets untouched and use them as is for
2980 - These section offsets were properly reset earlier, and thus
2981 already contain the correct values. This can happen for instance
2982 when reconnecting via the remote protocol to a target that supports
2983 the `qOffsets' packet.
2985 - The section offsets were not reset earlier, and the best we can
2986 hope is that the old offsets are still applicable to the new run. */
2988 if (! svr4_exec_displacement (&displacement))
2991 /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file
2994 if (symfile_objfile)
2996 struct section_offsets *new_offsets;
2999 new_offsets = alloca (symfile_objfile->num_sections
3000 * sizeof (*new_offsets));
3002 for (i = 0; i < symfile_objfile->num_sections; i++)
3003 new_offsets->offsets[i] = displacement;
3005 objfile_relocate (symfile_objfile, new_offsets);
3011 for (asect = exec_bfd->sections; asect != NULL; asect = asect->next)
3012 exec_set_section_address (bfd_get_filename (exec_bfd), asect->index,
3013 (bfd_section_vma (exec_bfd, asect)
3018 /* Implement the "create_inferior_hook" target_solib_ops method.
3020 For SVR4 executables, this first instruction is either the first
3021 instruction in the dynamic linker (for dynamically linked
3022 executables) or the instruction at "start" for statically linked
3023 executables. For dynamically linked executables, the system
3024 first exec's /lib/libc.so.N, which contains the dynamic linker,
3025 and starts it running. The dynamic linker maps in any needed
3026 shared libraries, maps in the actual user executable, and then
3027 jumps to "start" in the user executable.
3029 We can arrange to cooperate with the dynamic linker to discover the
3030 names of shared libraries that are dynamically linked, and the base
3031 addresses to which they are linked.
3033 This function is responsible for discovering those names and
3034 addresses, and saving sufficient information about them to allow
3035 their symbols to be read at a later time. */
3038 svr4_solib_create_inferior_hook (int from_tty)
3040 struct svr4_info *info;
3042 info = get_svr4_info ();
3044 /* Clear the probes-based interface's state. */
3045 free_probes_table (info);
3046 free_solib_list (info);
3048 /* Relocate the main executable if necessary. */
3049 svr4_relocate_main_executable ();
3051 /* No point setting a breakpoint in the dynamic linker if we can't
3052 hit it (e.g., a core file, or a trace file). */
3053 if (!target_has_execution)
3056 if (!svr4_have_link_map_offsets ())
3059 if (!enable_break (info, from_tty))
3064 svr4_clear_solib (void)
3066 struct svr4_info *info;
3068 info = get_svr4_info ();
3069 info->debug_base = 0;
3070 info->debug_loader_offset_p = 0;
3071 info->debug_loader_offset = 0;
3072 xfree (info->debug_loader_name);
3073 info->debug_loader_name = NULL;
3076 /* Clear any bits of ADDR that wouldn't fit in a target-format
3077 data pointer. "Data pointer" here refers to whatever sort of
3078 address the dynamic linker uses to manage its sections. At the
3079 moment, we don't support shared libraries on any processors where
3080 code and data pointers are different sizes.
3082 This isn't really the right solution. What we really need here is
3083 a way to do arithmetic on CORE_ADDR values that respects the
3084 natural pointer/address correspondence. (For example, on the MIPS,
3085 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
3086 sign-extend the value. There, simply truncating the bits above
3087 gdbarch_ptr_bit, as we do below, is no good.) This should probably
3088 be a new gdbarch method or something. */
3090 svr4_truncate_ptr (CORE_ADDR addr)
3092 if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR) * 8)
3093 /* We don't need to truncate anything, and the bit twiddling below
3094 will fail due to overflow problems. */
3097 return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1);
3102 svr4_relocate_section_addresses (struct so_list *so,
3103 struct target_section *sec)
3105 bfd *abfd = sec->the_bfd_section->owner;
3107 sec->addr = svr4_truncate_ptr (sec->addr + lm_addr_check (so, abfd));
3108 sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so, abfd));
3112 /* Architecture-specific operations. */
3114 /* Per-architecture data key. */
3115 static struct gdbarch_data *solib_svr4_data;
3117 struct solib_svr4_ops
3119 /* Return a description of the layout of `struct link_map'. */
3120 struct link_map_offsets *(*fetch_link_map_offsets)(void);
3123 /* Return a default for the architecture-specific operations. */
3126 solib_svr4_init (struct obstack *obstack)
3128 struct solib_svr4_ops *ops;
3130 ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops);
3131 ops->fetch_link_map_offsets = NULL;
3135 /* Set the architecture-specific `struct link_map_offsets' fetcher for
3136 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
3139 set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch,
3140 struct link_map_offsets *(*flmo) (void))
3142 struct solib_svr4_ops *ops = gdbarch_data (gdbarch, solib_svr4_data);
3144 ops->fetch_link_map_offsets = flmo;
3146 set_solib_ops (gdbarch, &svr4_so_ops);
3149 /* Fetch a link_map_offsets structure using the architecture-specific
3150 `struct link_map_offsets' fetcher. */
3152 static struct link_map_offsets *
3153 svr4_fetch_link_map_offsets (void)
3155 struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch (), solib_svr4_data);
3157 gdb_assert (ops->fetch_link_map_offsets);
3158 return ops->fetch_link_map_offsets ();
3161 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
3164 svr4_have_link_map_offsets (void)
3166 struct solib_svr4_ops *ops = gdbarch_data (target_gdbarch (), solib_svr4_data);
3168 return (ops->fetch_link_map_offsets != NULL);
3172 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
3173 `struct r_debug' and a `struct link_map' that are binary compatible
3174 with the origional SVR4 implementation. */
3176 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3177 for an ILP32 SVR4 system. */
3179 struct link_map_offsets *
3180 svr4_ilp32_fetch_link_map_offsets (void)
3182 static struct link_map_offsets lmo;
3183 static struct link_map_offsets *lmp = NULL;
3189 lmo.r_version_offset = 0;
3190 lmo.r_version_size = 4;
3191 lmo.r_map_offset = 4;
3192 lmo.r_brk_offset = 8;
3193 lmo.r_ldsomap_offset = 20;
3195 /* Everything we need is in the first 20 bytes. */
3196 lmo.link_map_size = 20;
3197 lmo.l_addr_offset = 0;
3198 lmo.l_name_offset = 4;
3199 lmo.l_ld_offset = 8;
3200 lmo.l_next_offset = 12;
3201 lmo.l_prev_offset = 16;
3207 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3208 for an LP64 SVR4 system. */
3210 struct link_map_offsets *
3211 svr4_lp64_fetch_link_map_offsets (void)
3213 static struct link_map_offsets lmo;
3214 static struct link_map_offsets *lmp = NULL;
3220 lmo.r_version_offset = 0;
3221 lmo.r_version_size = 4;
3222 lmo.r_map_offset = 8;
3223 lmo.r_brk_offset = 16;
3224 lmo.r_ldsomap_offset = 40;
3226 /* Everything we need is in the first 40 bytes. */
3227 lmo.link_map_size = 40;
3228 lmo.l_addr_offset = 0;
3229 lmo.l_name_offset = 8;
3230 lmo.l_ld_offset = 16;
3231 lmo.l_next_offset = 24;
3232 lmo.l_prev_offset = 32;
3239 struct target_so_ops svr4_so_ops;
3241 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
3242 different rule for symbol lookup. The lookup begins here in the DSO, not in
3243 the main executable. */
3245 static struct block_symbol
3246 elf_lookup_lib_symbol (struct objfile *objfile,
3248 const domain_enum domain)
3252 if (objfile == symfile_objfile)
3256 /* OBJFILE should have been passed as the non-debug one. */
3257 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
3259 abfd = objfile->obfd;
3262 if (abfd == NULL || scan_dyntag (DT_SYMBOLIC, abfd, NULL, NULL) != 1)
3263 return (struct block_symbol) {NULL, NULL};
3265 return lookup_global_symbol_from_objfile (objfile, name, domain);
3268 extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */
3271 _initialize_svr4_solib (void)
3273 solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init);
3274 solib_svr4_pspace_data
3275 = register_program_space_data_with_cleanup (NULL, svr4_pspace_data_cleanup);
3277 svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses;
3278 svr4_so_ops.free_so = svr4_free_so;
3279 svr4_so_ops.clear_so = svr4_clear_so;
3280 svr4_so_ops.clear_solib = svr4_clear_solib;
3281 svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook;
3282 svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling;
3283 svr4_so_ops.current_sos = svr4_current_sos;
3284 svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
3285 svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code;
3286 svr4_so_ops.bfd_open = solib_bfd_open;
3287 svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol;
3288 svr4_so_ops.same = svr4_same;
3289 svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core;
3290 svr4_so_ops.update_breakpoints = svr4_update_solib_event_breakpoints;
3291 svr4_so_ops.handle_event = svr4_handle_solib_event;