1 /* Handle SVR4 shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990-2022 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "elf/external.h"
23 #include "elf/common.h"
35 #include "gdbthread.h"
36 #include "observable.h"
40 #include "solib-svr4.h"
42 #include "bfd-target.h"
49 static struct link_map_offsets
*svr4_fetch_link_map_offsets (void);
50 static int svr4_have_link_map_offsets (void);
51 static void svr4_relocate_main_executable (void);
52 static void svr4_free_library_list (void *p_list
);
53 static void probes_table_remove_objfile_probes (struct objfile
*objfile
);
54 static void svr4_iterate_over_objfiles_in_search_order
55 (gdbarch
*gdbarch
, iterate_over_objfiles_in_search_order_cb_ftype cb
,
56 objfile
*current_objfile
);
59 /* On SVR4 systems, a list of symbols in the dynamic linker where
60 GDB can try to place a breakpoint to monitor shared library
63 If none of these symbols are found, or other errors occur, then
64 SVR4 systems will fall back to using a symbol as the "startup
65 mapping complete" breakpoint address. */
67 static const char * const solib_break_names
[] =
73 "__dl_rtld_db_dlactivity",
79 static const char * const bkpt_names
[] =
87 static const char * const main_name_list
[] =
93 /* What to do when a probe stop occurs. */
97 /* Something went seriously wrong. Stop using probes and
98 revert to using the older interface. */
99 PROBES_INTERFACE_FAILED
,
101 /* No action is required. The shared object list is still
105 /* The shared object list should be reloaded entirely. */
108 /* Attempt to incrementally update the shared object list. If
109 the update fails or is not possible, fall back to reloading
114 /* A probe's name and its associated action. */
118 /* The name of the probe. */
121 /* What to do when a probe stop occurs. */
122 enum probe_action action
;
125 /* A list of named probes and their associated actions. If all
126 probes are present in the dynamic linker then the probes-based
127 interface will be used. */
129 static const struct probe_info probe_info
[] =
131 { "init_start", DO_NOTHING
},
132 { "init_complete", FULL_RELOAD
},
133 { "map_start", DO_NOTHING
},
134 { "map_failed", DO_NOTHING
},
135 { "reloc_complete", UPDATE_OR_RELOAD
},
136 { "unmap_start", DO_NOTHING
},
137 { "unmap_complete", FULL_RELOAD
},
140 #define NUM_PROBES ARRAY_SIZE (probe_info)
142 /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
143 the same shared library. */
146 svr4_same_1 (const char *gdb_so_name
, const char *inferior_so_name
)
148 if (strcmp (gdb_so_name
, inferior_so_name
) == 0)
151 /* On Solaris, when starting inferior we think that dynamic linker is
152 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
153 contains /lib/ld.so.1. Sometimes one file is a link to another, but
154 sometimes they have identical content, but are not linked to each
155 other. We don't restrict this check for Solaris, but the chances
156 of running into this situation elsewhere are very low. */
157 if (strcmp (gdb_so_name
, "/usr/lib/ld.so.1") == 0
158 && strcmp (inferior_so_name
, "/lib/ld.so.1") == 0)
161 /* Similarly, we observed the same issue with amd64 and sparcv9, but with
162 different locations. */
163 if (strcmp (gdb_so_name
, "/usr/lib/amd64/ld.so.1") == 0
164 && strcmp (inferior_so_name
, "/lib/amd64/ld.so.1") == 0)
167 if (strcmp (gdb_so_name
, "/usr/lib/sparcv9/ld.so.1") == 0
168 && strcmp (inferior_so_name
, "/lib/sparcv9/ld.so.1") == 0)
175 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
177 return (svr4_same_1 (gdb
->so_original_name
, inferior
->so_original_name
));
180 static std::unique_ptr
<lm_info_svr4
>
181 lm_info_read (CORE_ADDR lm_addr
)
183 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
184 std::unique_ptr
<lm_info_svr4
> lm_info
;
186 gdb::byte_vector
lm (lmo
->link_map_size
);
188 if (target_read_memory (lm_addr
, lm
.data (), lmo
->link_map_size
) != 0)
189 warning (_("Error reading shared library list entry at %s"),
190 paddress (target_gdbarch (), lm_addr
));
193 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
195 lm_info
.reset (new lm_info_svr4
);
196 lm_info
->lm_addr
= lm_addr
;
198 lm_info
->l_addr_inferior
= extract_typed_address (&lm
[lmo
->l_addr_offset
],
200 lm_info
->l_ld
= extract_typed_address (&lm
[lmo
->l_ld_offset
], ptr_type
);
201 lm_info
->l_next
= extract_typed_address (&lm
[lmo
->l_next_offset
],
203 lm_info
->l_prev
= extract_typed_address (&lm
[lmo
->l_prev_offset
],
205 lm_info
->l_name
= extract_typed_address (&lm
[lmo
->l_name_offset
],
213 has_lm_dynamic_from_link_map (void)
215 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
217 return lmo
->l_ld_offset
>= 0;
221 lm_addr_check (const struct so_list
*so
, bfd
*abfd
)
223 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
227 struct bfd_section
*dyninfo_sect
;
228 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
;
230 l_addr
= li
->l_addr_inferior
;
232 if (! abfd
|| ! has_lm_dynamic_from_link_map ())
235 l_dynaddr
= li
->l_ld
;
237 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
238 if (dyninfo_sect
== NULL
)
241 dynaddr
= bfd_section_vma (dyninfo_sect
);
243 if (dynaddr
+ l_addr
!= l_dynaddr
)
245 CORE_ADDR align
= 0x1000;
246 CORE_ADDR minpagesize
= align
;
248 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
250 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
251 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
256 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
257 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
258 align
= phdr
[i
].p_align
;
260 minpagesize
= get_elf_backend_data (abfd
)->minpagesize
;
263 /* Turn it into a mask. */
266 /* If the changes match the alignment requirements, we
267 assume we're using a core file that was generated by the
268 same binary, just prelinked with a different base offset.
269 If it doesn't match, we may have a different binary, the
270 same binary with the dynamic table loaded at an unrelated
271 location, or anything, really. To avoid regressions,
272 don't adjust the base offset in the latter case, although
273 odds are that, if things really changed, debugging won't
276 One could expect more the condition
277 ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
278 but the one below is relaxed for PPC. The PPC kernel supports
279 either 4k or 64k page sizes. To be prepared for 64k pages,
280 PPC ELF files are built using an alignment requirement of 64k.
281 However, when running on a kernel supporting 4k pages, the memory
282 mapping of the library may not actually happen on a 64k boundary!
284 (In the usual case where (l_addr & align) == 0, this check is
285 equivalent to the possibly expected check above.)
287 Even on PPC it must be zero-aligned at least for MINPAGESIZE. */
289 l_addr
= l_dynaddr
- dynaddr
;
291 if ((l_addr
& (minpagesize
- 1)) == 0
292 && (l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
295 gdb_printf (_("Using PIC (Position Independent Code) "
296 "prelink displacement %s for \"%s\".\n"),
297 paddress (target_gdbarch (), l_addr
),
302 /* There is no way to verify the library file matches. prelink
303 can during prelinking of an unprelinked file (or unprelinking
304 of a prelinked file) shift the DYNAMIC segment by arbitrary
305 offset without any page size alignment. There is no way to
306 find out the ELF header and/or Program Headers for a limited
307 verification if it they match. One could do a verification
308 of the DYNAMIC segment. Still the found address is the best
309 one GDB could find. */
311 warning (_(".dynamic section for \"%s\" "
312 "is not at the expected address "
313 "(wrong library or version mismatch?)"), so
->so_name
);
325 /* Per pspace SVR4 specific data. */
329 svr4_info () = default;
332 /* Base of dynamic linker structures. */
333 CORE_ADDR debug_base
= 0;
335 /* Validity flag for debug_loader_offset. */
336 int debug_loader_offset_p
= 0;
338 /* Load address for the dynamic linker, inferred. */
339 CORE_ADDR debug_loader_offset
= 0;
341 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
342 char *debug_loader_name
= nullptr;
344 /* Load map address for the main executable. */
345 CORE_ADDR main_lm_addr
= 0;
347 CORE_ADDR interp_text_sect_low
= 0;
348 CORE_ADDR interp_text_sect_high
= 0;
349 CORE_ADDR interp_plt_sect_low
= 0;
350 CORE_ADDR interp_plt_sect_high
= 0;
352 /* Nonzero if the list of objects was last obtained from the target
353 via qXfer:libraries-svr4:read. */
356 /* Table of struct probe_and_action instances, used by the
357 probes-based interface to map breakpoint addresses to probes
358 and their associated actions. Lookup is performed using
359 probe_and_action->prob->address. */
360 htab_up probes_table
;
362 /* List of objects loaded into the inferior, used by the probes-
364 struct so_list
*solib_list
= nullptr;
367 /* Per-program-space data key. */
368 static const registry
<program_space
>::key
<svr4_info
> solib_svr4_pspace_data
;
370 /* Free the probes table. */
373 free_probes_table (struct svr4_info
*info
)
375 info
->probes_table
.reset (nullptr);
378 /* Free the solib list. */
381 free_solib_list (struct svr4_info
*info
)
383 svr4_free_library_list (&info
->solib_list
);
384 info
->solib_list
= NULL
;
387 svr4_info::~svr4_info ()
389 free_solib_list (this);
392 /* Get the svr4 data for program space PSPACE. If none is found yet, add it now.
393 This function always returns a valid object. */
395 static struct svr4_info
*
396 get_svr4_info (program_space
*pspace
)
398 struct svr4_info
*info
= solib_svr4_pspace_data
.get (pspace
);
401 info
= solib_svr4_pspace_data
.emplace (pspace
);
406 /* Local function prototypes */
408 static int match_main (const char *);
410 /* Read program header TYPE from inferior memory. The header is found
411 by scanning the OS auxiliary vector.
413 If TYPE == -1, return the program headers instead of the contents of
416 Return vector of bytes holding the program header contents, or an empty
417 optional on failure. If successful and P_ARCH_SIZE is non-NULL, the target
418 architecture size (32-bit or 64-bit) is returned to *P_ARCH_SIZE. Likewise,
419 the base address of the section is returned in *BASE_ADDR. */
421 static gdb::optional
<gdb::byte_vector
>
422 read_program_header (int type
, int *p_arch_size
, CORE_ADDR
*base_addr
)
424 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
425 CORE_ADDR at_phdr
, at_phent
, at_phnum
, pt_phdr
= 0;
426 int arch_size
, sect_size
;
430 /* Get required auxv elements from target. */
431 if (target_auxv_search (AT_PHDR
, &at_phdr
) <= 0)
433 if (target_auxv_search (AT_PHENT
, &at_phent
) <= 0)
435 if (target_auxv_search (AT_PHNUM
, &at_phnum
) <= 0)
437 if (!at_phdr
|| !at_phnum
)
440 /* Determine ELF architecture type. */
441 if (at_phent
== sizeof (Elf32_External_Phdr
))
443 else if (at_phent
== sizeof (Elf64_External_Phdr
))
448 /* Find the requested segment. */
452 sect_size
= at_phent
* at_phnum
;
454 else if (arch_size
== 32)
456 Elf32_External_Phdr phdr
;
459 /* Search for requested PHDR. */
460 for (i
= 0; i
< at_phnum
; i
++)
464 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
465 (gdb_byte
*)&phdr
, sizeof (phdr
)))
468 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
471 if (p_type
== PT_PHDR
)
474 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
485 /* Retrieve address and size. */
486 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
488 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
493 Elf64_External_Phdr phdr
;
496 /* Search for requested PHDR. */
497 for (i
= 0; i
< at_phnum
; i
++)
501 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
502 (gdb_byte
*)&phdr
, sizeof (phdr
)))
505 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
508 if (p_type
== PT_PHDR
)
511 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
522 /* Retrieve address and size. */
523 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
525 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
529 /* PT_PHDR is optional, but we really need it
530 for PIE to make this work in general. */
534 /* at_phdr is real address in memory. pt_phdr is what pheader says it is.
535 Relocation offset is the difference between the two. */
536 sect_addr
= sect_addr
+ (at_phdr
- pt_phdr
);
539 /* Read in requested program header. */
540 gdb::byte_vector
buf (sect_size
);
541 if (target_read_memory (sect_addr
, buf
.data (), sect_size
))
545 *p_arch_size
= arch_size
;
547 *base_addr
= sect_addr
;
553 /* Return program interpreter string. */
554 static gdb::optional
<gdb::byte_vector
>
555 find_program_interpreter (void)
557 /* If we have a current exec_bfd, use its section table. */
558 if (current_program_space
->exec_bfd ()
559 && (bfd_get_flavour (current_program_space
->exec_bfd ())
560 == bfd_target_elf_flavour
))
562 struct bfd_section
*interp_sect
;
564 interp_sect
= bfd_get_section_by_name (current_program_space
->exec_bfd (),
566 if (interp_sect
!= NULL
)
568 int sect_size
= bfd_section_size (interp_sect
);
570 gdb::byte_vector
buf (sect_size
);
571 bfd_get_section_contents (current_program_space
->exec_bfd (),
572 interp_sect
, buf
.data (), 0, sect_size
);
577 /* If we didn't find it, use the target auxiliary vector. */
578 return read_program_header (PT_INTERP
, NULL
, NULL
);
582 /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable,
583 found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1
584 is returned and the corresponding PTR is set. */
587 scan_dyntag_auxv (const int desired_dyntag
, CORE_ADDR
*ptr
,
590 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
596 /* Read in .dynamic section. */
597 gdb::optional
<gdb::byte_vector
> ph_data
598 = read_program_header (PT_DYNAMIC
, &arch_size
, &base_addr
);
602 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
603 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
604 : sizeof (Elf64_External_Dyn
);
605 for (gdb_byte
*buf
= ph_data
->data (), *bufend
= buf
+ ph_data
->size ();
606 buf
< bufend
; buf
+= step
)
610 Elf32_External_Dyn
*dynp
= (Elf32_External_Dyn
*) buf
;
612 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
614 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
619 Elf64_External_Dyn
*dynp
= (Elf64_External_Dyn
*) buf
;
621 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
623 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
626 if (current_dyntag
== DT_NULL
)
629 if (current_dyntag
== desired_dyntag
)
635 *ptr_addr
= base_addr
+ buf
- ph_data
->data ();
644 /* Locate the base address of dynamic linker structs for SVR4 elf
647 For SVR4 elf targets the address of the dynamic linker's runtime
648 structure is contained within the dynamic info section in the
649 executable file. The dynamic section is also mapped into the
650 inferior address space. Because the runtime loader fills in the
651 real address before starting the inferior, we have to read in the
652 dynamic info section from the inferior address space.
653 If there are any errors while trying to find the address, we
654 silently return 0, otherwise the found address is returned. */
657 elf_locate_base (void)
659 struct bound_minimal_symbol msymbol
;
660 CORE_ADDR dyn_ptr
, dyn_ptr_addr
;
662 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
663 instead of DT_DEBUG, although they sometimes contain an unused
665 if (gdb_bfd_scan_elf_dyntag (DT_MIPS_RLD_MAP
,
666 current_program_space
->exec_bfd (),
668 || scan_dyntag_auxv (DT_MIPS_RLD_MAP
, &dyn_ptr
, NULL
))
670 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
672 int pbuf_size
= ptr_type
->length ();
674 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
675 /* DT_MIPS_RLD_MAP contains a pointer to the address
676 of the dynamic link structure. */
677 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
679 return extract_typed_address (pbuf
, ptr_type
);
682 /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form
683 because of needing to support PIE. DT_MIPS_RLD_MAP will also exist
685 if (gdb_bfd_scan_elf_dyntag (DT_MIPS_RLD_MAP_REL
,
686 current_program_space
->exec_bfd (),
687 &dyn_ptr
, &dyn_ptr_addr
)
688 || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL
, &dyn_ptr
, &dyn_ptr_addr
))
690 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
692 int pbuf_size
= ptr_type
->length ();
694 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
695 /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the
696 DT slot to the address of the dynamic link structure. */
697 if (target_read_memory (dyn_ptr
+ dyn_ptr_addr
, pbuf
, pbuf_size
))
699 return extract_typed_address (pbuf
, ptr_type
);
703 if (gdb_bfd_scan_elf_dyntag (DT_DEBUG
, current_program_space
->exec_bfd (),
705 || scan_dyntag_auxv (DT_DEBUG
, &dyn_ptr
, NULL
))
708 /* This may be a static executable. Look for the symbol
709 conventionally named _r_debug, as a last resort. */
710 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
,
711 current_program_space
->symfile_object_file
);
712 if (msymbol
.minsym
!= NULL
)
713 return msymbol
.value_address ();
715 /* DT_DEBUG entry not found. */
719 /* Locate the base address of dynamic linker structs.
721 For both the SunOS and SVR4 shared library implementations, if the
722 inferior executable has been linked dynamically, there is a single
723 address somewhere in the inferior's data space which is the key to
724 locating all of the dynamic linker's runtime structures. This
725 address is the value of the debug base symbol. The job of this
726 function is to find and return that address, or to return 0 if there
727 is no such address (the executable is statically linked for example).
729 For SunOS, the job is almost trivial, since the dynamic linker and
730 all of it's structures are statically linked to the executable at
731 link time. Thus the symbol for the address we are looking for has
732 already been added to the minimal symbol table for the executable's
733 objfile at the time the symbol file's symbols were read, and all we
734 have to do is look it up there. Note that we explicitly do NOT want
735 to find the copies in the shared library.
737 The SVR4 version is a bit more complicated because the address
738 is contained somewhere in the dynamic info section. We have to go
739 to a lot more work to discover the address of the debug base symbol.
740 Because of this complexity, we cache the value we find and return that
741 value on subsequent invocations. Note there is no copy in the
742 executable symbol tables. */
745 locate_base (struct svr4_info
*info
)
747 /* Check to see if we have a currently valid address, and if so, avoid
748 doing all this work again and just return the cached address. If
749 we have no cached address, try to locate it in the dynamic info
750 section for ELF executables. There's no point in doing any of this
751 though if we don't have some link map offsets to work with. */
753 if (info
->debug_base
== 0 && svr4_have_link_map_offsets ())
754 info
->debug_base
= elf_locate_base ();
755 return info
->debug_base
;
758 /* Find the first element in the inferior's dynamic link map, and
759 return its address in the inferior. Return zero if the address
760 could not be determined.
762 FIXME: Perhaps we should validate the info somehow, perhaps by
763 checking r_version for a known version number, or r_state for
767 solib_svr4_r_map (struct svr4_info
*info
)
769 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
770 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
775 addr
= read_memory_typed_address (info
->debug_base
+ lmo
->r_map_offset
,
778 catch (const gdb_exception_error
&ex
)
780 exception_print (gdb_stderr
, ex
);
786 /* Find r_brk from the inferior's debug base. */
789 solib_svr4_r_brk (struct svr4_info
*info
)
791 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
792 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
794 return read_memory_typed_address (info
->debug_base
+ lmo
->r_brk_offset
,
798 /* Find the link map for the dynamic linker (if it is not in the
799 normal list of loaded shared objects). */
802 solib_svr4_r_ldsomap (struct svr4_info
*info
)
804 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
805 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
806 enum bfd_endian byte_order
= type_byte_order (ptr_type
);
807 ULONGEST version
= 0;
811 /* Check version, and return zero if `struct r_debug' doesn't have
812 the r_ldsomap member. */
814 = read_memory_unsigned_integer (info
->debug_base
+ lmo
->r_version_offset
,
815 lmo
->r_version_size
, byte_order
);
817 catch (const gdb_exception_error
&ex
)
819 exception_print (gdb_stderr
, ex
);
822 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
825 return read_memory_typed_address (info
->debug_base
+ lmo
->r_ldsomap_offset
,
829 /* On Solaris systems with some versions of the dynamic linker,
830 ld.so's l_name pointer points to the SONAME in the string table
831 rather than into writable memory. So that GDB can find shared
832 libraries when loading a core file generated by gcore, ensure that
833 memory areas containing the l_name string are saved in the core
837 svr4_keep_data_in_core (CORE_ADDR vaddr
, unsigned long size
)
839 struct svr4_info
*info
;
843 info
= get_svr4_info (current_program_space
);
845 info
->debug_base
= 0;
847 if (!info
->debug_base
)
850 ldsomap
= solib_svr4_r_ldsomap (info
);
854 std::unique_ptr
<lm_info_svr4
> li
= lm_info_read (ldsomap
);
855 name_lm
= li
!= NULL
? li
->l_name
: 0;
857 return (name_lm
>= vaddr
&& name_lm
< vaddr
+ size
);
863 open_symbol_file_object (int from_tty
)
865 CORE_ADDR lm
, l_name
;
866 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
867 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
868 int l_name_size
= ptr_type
->length ();
869 gdb::byte_vector
l_name_buf (l_name_size
);
870 struct svr4_info
*info
= get_svr4_info (current_program_space
);
871 symfile_add_flags add_flags
= 0;
874 add_flags
|= SYMFILE_VERBOSE
;
876 if (current_program_space
->symfile_object_file
)
877 if (!query (_("Attempt to reload symbols from process? ")))
880 /* Always locate the debug struct, in case it has moved. */
881 info
->debug_base
= 0;
882 if (locate_base (info
) == 0)
883 return 0; /* failed somehow... */
885 /* First link map member should be the executable. */
886 lm
= solib_svr4_r_map (info
);
888 return 0; /* failed somehow... */
890 /* Read address of name from target memory to GDB. */
891 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
.data (), l_name_size
);
893 /* Convert the address to host format. */
894 l_name
= extract_typed_address (l_name_buf
.data (), ptr_type
);
897 return 0; /* No filename. */
899 /* Now fetch the filename from target memory. */
900 gdb::unique_xmalloc_ptr
<char> filename
901 = target_read_string (l_name
, SO_NAME_MAX_PATH_SIZE
- 1);
903 if (filename
== nullptr)
905 warning (_("failed to read exec filename from attached file"));
909 /* Have a pathname: read the symbol file. */
910 symbol_file_add_main (filename
.get (), add_flags
);
915 /* Data exchange structure for the XML parser as returned by
916 svr4_current_sos_via_xfer_libraries. */
918 struct svr4_library_list
920 struct so_list
*head
, **tailp
;
922 /* Inferior address of struct link_map used for the main executable. It is
923 NULL if not known. */
927 /* This module's 'free_objfile' observer. */
930 svr4_free_objfile_observer (struct objfile
*objfile
)
932 probes_table_remove_objfile_probes (objfile
);
935 /* Implementation for target_so_ops.free_so. */
938 svr4_free_so (struct so_list
*so
)
940 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
945 /* Implement target_so_ops.clear_so. */
948 svr4_clear_so (struct so_list
*so
)
950 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
956 /* Free so_list built so far (called via cleanup). */
959 svr4_free_library_list (void *p_list
)
961 struct so_list
*list
= *(struct so_list
**) p_list
;
965 struct so_list
*next
= list
->next
;
972 /* Copy library list. */
974 static struct so_list
*
975 svr4_copy_library_list (struct so_list
*src
)
977 struct so_list
*dst
= NULL
;
978 struct so_list
**link
= &dst
;
982 struct so_list
*newobj
;
984 newobj
= XNEW (struct so_list
);
985 memcpy (newobj
, src
, sizeof (struct so_list
));
987 lm_info_svr4
*src_li
= (lm_info_svr4
*) src
->lm_info
;
988 newobj
->lm_info
= new lm_info_svr4 (*src_li
);
992 link
= &newobj
->next
;
1000 #ifdef HAVE_LIBEXPAT
1002 #include "xml-support.h"
1004 /* Handle the start of a <library> element. Note: new elements are added
1005 at the tail of the list, keeping the list in order. */
1008 library_list_start_library (struct gdb_xml_parser
*parser
,
1009 const struct gdb_xml_element
*element
,
1011 std::vector
<gdb_xml_value
> &attributes
)
1013 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1015 = (const char *) xml_find_attribute (attributes
, "name")->value
.get ();
1017 = (ULONGEST
*) xml_find_attribute (attributes
, "lm")->value
.get ();
1019 = (ULONGEST
*) xml_find_attribute (attributes
, "l_addr")->value
.get ();
1021 = (ULONGEST
*) xml_find_attribute (attributes
, "l_ld")->value
.get ();
1022 struct so_list
*new_elem
;
1024 new_elem
= XCNEW (struct so_list
);
1025 lm_info_svr4
*li
= new lm_info_svr4
;
1026 new_elem
->lm_info
= li
;
1028 li
->l_addr_inferior
= *l_addrp
;
1031 strncpy (new_elem
->so_name
, name
, sizeof (new_elem
->so_name
) - 1);
1032 new_elem
->so_name
[sizeof (new_elem
->so_name
) - 1] = 0;
1033 strcpy (new_elem
->so_original_name
, new_elem
->so_name
);
1035 *list
->tailp
= new_elem
;
1036 list
->tailp
= &new_elem
->next
;
1039 /* Handle the start of a <library-list-svr4> element. */
1042 svr4_library_list_start_list (struct gdb_xml_parser
*parser
,
1043 const struct gdb_xml_element
*element
,
1045 std::vector
<gdb_xml_value
> &attributes
)
1047 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1049 = (const char *) xml_find_attribute (attributes
, "version")->value
.get ();
1050 struct gdb_xml_value
*main_lm
= xml_find_attribute (attributes
, "main-lm");
1052 if (strcmp (version
, "1.0") != 0)
1053 gdb_xml_error (parser
,
1054 _("SVR4 Library list has unsupported version \"%s\""),
1058 list
->main_lm
= *(ULONGEST
*) main_lm
->value
.get ();
1061 /* The allowed elements and attributes for an XML library list.
1062 The root element is a <library-list>. */
1064 static const struct gdb_xml_attribute svr4_library_attributes
[] =
1066 { "name", GDB_XML_AF_NONE
, NULL
, NULL
},
1067 { "lm", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1068 { "l_addr", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1069 { "l_ld", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1070 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1073 static const struct gdb_xml_element svr4_library_list_children
[] =
1076 "library", svr4_library_attributes
, NULL
,
1077 GDB_XML_EF_REPEATABLE
| GDB_XML_EF_OPTIONAL
,
1078 library_list_start_library
, NULL
1080 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1083 static const struct gdb_xml_attribute svr4_library_list_attributes
[] =
1085 { "version", GDB_XML_AF_NONE
, NULL
, NULL
},
1086 { "main-lm", GDB_XML_AF_OPTIONAL
, gdb_xml_parse_attr_ulongest
, NULL
},
1087 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1090 static const struct gdb_xml_element svr4_library_list_elements
[] =
1092 { "library-list-svr4", svr4_library_list_attributes
, svr4_library_list_children
,
1093 GDB_XML_EF_NONE
, svr4_library_list_start_list
, NULL
},
1094 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1097 /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if
1099 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1100 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1101 empty, caller is responsible for freeing all its entries. */
1104 svr4_parse_libraries (const char *document
, struct svr4_library_list
*list
)
1106 auto cleanup
= make_scope_exit ([&] ()
1108 svr4_free_library_list (&list
->head
);
1111 memset (list
, 0, sizeof (*list
));
1112 list
->tailp
= &list
->head
;
1113 if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd",
1114 svr4_library_list_elements
, document
, list
) == 0)
1116 /* Parsed successfully, keep the result. */
1124 /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet.
1126 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1127 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1128 empty, caller is responsible for freeing all its entries.
1130 Note that ANNEX must be NULL if the remote does not explicitly allow
1131 qXfer:libraries-svr4:read packets with non-empty annexes. Support for
1132 this can be checked using target_augmented_libraries_svr4_read (). */
1135 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1138 gdb_assert (annex
== NULL
|| target_augmented_libraries_svr4_read ());
1140 /* Fetch the list of shared libraries. */
1141 gdb::optional
<gdb::char_vector
> svr4_library_document
1142 = target_read_stralloc (current_inferior ()->top_target (),
1143 TARGET_OBJECT_LIBRARIES_SVR4
,
1145 if (!svr4_library_document
)
1148 return svr4_parse_libraries (svr4_library_document
->data (), list
);
1154 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1162 /* If no shared library information is available from the dynamic
1163 linker, build a fallback list from other sources. */
1165 static struct so_list
*
1166 svr4_default_sos (svr4_info
*info
)
1168 struct so_list
*newobj
;
1170 if (!info
->debug_loader_offset_p
)
1173 newobj
= XCNEW (struct so_list
);
1174 lm_info_svr4
*li
= new lm_info_svr4
;
1175 newobj
->lm_info
= li
;
1177 /* Nothing will ever check the other fields if we set l_addr_p. */
1178 li
->l_addr
= info
->debug_loader_offset
;
1181 strncpy (newobj
->so_name
, info
->debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
1182 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1183 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1188 /* Read the whole inferior libraries chain starting at address LM.
1189 Expect the first entry in the chain's previous entry to be PREV_LM.
1190 Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the
1191 first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according
1192 to it. Returns nonzero upon success. If zero is returned the
1193 entries stored to LINK_PTR_PTR are still valid although they may
1194 represent only part of the inferior library list. */
1197 svr4_read_so_list (svr4_info
*info
, CORE_ADDR lm
, CORE_ADDR prev_lm
,
1198 struct so_list
***link_ptr_ptr
, int ignore_first
)
1200 CORE_ADDR first_l_name
= 0;
1203 for (; lm
!= 0; prev_lm
= lm
, lm
= next_lm
)
1205 so_list_up
newobj (XCNEW (struct so_list
));
1207 lm_info_svr4
*li
= lm_info_read (lm
).release ();
1208 newobj
->lm_info
= li
;
1212 next_lm
= li
->l_next
;
1214 if (li
->l_prev
!= prev_lm
)
1216 warning (_("Corrupted shared library list: %s != %s"),
1217 paddress (target_gdbarch (), prev_lm
),
1218 paddress (target_gdbarch (), li
->l_prev
));
1222 /* For SVR4 versions, the first entry in the link map is for the
1223 inferior executable, so we must ignore it. For some versions of
1224 SVR4, it has no name. For others (Solaris 2.3 for example), it
1225 does have a name, so we can no longer use a missing name to
1226 decide when to ignore it. */
1227 if (ignore_first
&& li
->l_prev
== 0)
1229 first_l_name
= li
->l_name
;
1230 info
->main_lm_addr
= li
->lm_addr
;
1234 /* Extract this shared object's name. */
1235 gdb::unique_xmalloc_ptr
<char> buffer
1236 = target_read_string (li
->l_name
, SO_NAME_MAX_PATH_SIZE
- 1);
1237 if (buffer
== nullptr)
1239 /* If this entry's l_name address matches that of the
1240 inferior executable, then this is not a normal shared
1241 object, but (most likely) a vDSO. In this case, silently
1242 skip it; otherwise emit a warning. */
1243 if (first_l_name
== 0 || li
->l_name
!= first_l_name
)
1244 warning (_("Can't read pathname for load map."));
1248 strncpy (newobj
->so_name
, buffer
.get (), SO_NAME_MAX_PATH_SIZE
- 1);
1249 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1250 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1252 /* If this entry has no name, or its name matches the name
1253 for the main executable, don't include it in the list. */
1254 if (! newobj
->so_name
[0] || match_main (newobj
->so_name
))
1258 /* Don't free it now. */
1259 **link_ptr_ptr
= newobj
.release ();
1260 *link_ptr_ptr
= &(**link_ptr_ptr
)->next
;
1266 /* Read the full list of currently loaded shared objects directly
1267 from the inferior, without referring to any libraries read and
1268 stored by the probes interface. Handle special cases relating
1269 to the first elements of the list. */
1271 static struct so_list
*
1272 svr4_current_sos_direct (struct svr4_info
*info
)
1275 struct so_list
*head
= NULL
;
1276 struct so_list
**link_ptr
= &head
;
1278 struct svr4_library_list library_list
;
1280 /* Fall back to manual examination of the target if the packet is not
1281 supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp
1282 tests a case where gdbserver cannot find the shared libraries list while
1283 GDB itself is able to find it via SYMFILE_OBJFILE.
1285 Unfortunately statically linked inferiors will also fall back through this
1286 suboptimal code path. */
1288 info
->using_xfer
= svr4_current_sos_via_xfer_libraries (&library_list
,
1290 if (info
->using_xfer
)
1292 if (library_list
.main_lm
)
1293 info
->main_lm_addr
= library_list
.main_lm
;
1295 return library_list
.head
? library_list
.head
: svr4_default_sos (info
);
1298 /* Always locate the debug struct, in case it has moved. */
1299 info
->debug_base
= 0;
1302 /* If we can't find the dynamic linker's base structure, this
1303 must not be a dynamically linked executable. Hmm. */
1304 if (! info
->debug_base
)
1305 return svr4_default_sos (info
);
1307 /* Assume that everything is a library if the dynamic loader was loaded
1308 late by a static executable. */
1309 if (current_program_space
->exec_bfd ()
1310 && bfd_get_section_by_name (current_program_space
->exec_bfd (),
1311 ".dynamic") == NULL
)
1316 auto cleanup
= make_scope_exit ([&] ()
1318 svr4_free_library_list (&head
);
1321 /* Walk the inferior's link map list, and build our list of
1322 `struct so_list' nodes. */
1323 lm
= solib_svr4_r_map (info
);
1325 svr4_read_so_list (info
, lm
, 0, &link_ptr
, ignore_first
);
1327 /* On Solaris, the dynamic linker is not in the normal list of
1328 shared objects, so make sure we pick it up too. Having
1329 symbol information for the dynamic linker is quite crucial
1330 for skipping dynamic linker resolver code. */
1331 lm
= solib_svr4_r_ldsomap (info
);
1333 svr4_read_so_list (info
, lm
, 0, &link_ptr
, 0);
1338 return svr4_default_sos (info
);
1343 /* Implement the main part of the "current_sos" target_so_ops
1346 static struct so_list
*
1347 svr4_current_sos_1 (svr4_info
*info
)
1349 /* If the solib list has been read and stored by the probes
1350 interface then we return a copy of the stored list. */
1351 if (info
->solib_list
!= NULL
)
1352 return svr4_copy_library_list (info
->solib_list
);
1354 /* Otherwise obtain the solib list directly from the inferior. */
1355 return svr4_current_sos_direct (info
);
1358 /* Implement the "current_sos" target_so_ops method. */
1360 static struct so_list
*
1361 svr4_current_sos (void)
1363 svr4_info
*info
= get_svr4_info (current_program_space
);
1364 struct so_list
*so_head
= svr4_current_sos_1 (info
);
1365 struct mem_range vsyscall_range
;
1367 /* Filter out the vDSO module, if present. Its symbol file would
1368 not be found on disk. The vDSO/vsyscall's OBJFILE is instead
1369 managed by symfile-mem.c:add_vsyscall_page. */
1370 if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range
)
1371 && vsyscall_range
.length
!= 0)
1373 struct so_list
**sop
;
1376 while (*sop
!= NULL
)
1378 struct so_list
*so
= *sop
;
1380 /* We can't simply match the vDSO by starting address alone,
1381 because lm_info->l_addr_inferior (and also l_addr) do not
1382 necessarily represent the real starting address of the
1383 ELF if the vDSO's ELF itself is "prelinked". The l_ld
1384 field (the ".dynamic" section of the shared object)
1385 always points at the absolute/resolved address though.
1386 So check whether that address is inside the vDSO's
1389 E.g., on Linux 3.16 (x86_64) the vDSO is a regular
1390 0-based ELF, and we see:
1393 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000
1394 (gdb) p/x *_r_debug.r_map.l_next
1395 $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...}
1397 And on Linux 2.6.32 (x86_64) we see:
1400 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000
1401 (gdb) p/x *_r_debug.r_map.l_next
1402 $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... }
1404 Dumping that vDSO shows:
1406 (gdb) info proc mappings
1407 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso]
1408 (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000
1409 # readelf -Wa vdso.bin
1411 Entry point address: 0xffffffffff700700
1414 [Nr] Name Type Address Off Size
1415 [ 0] NULL 0000000000000000 000000 000000
1416 [ 1] .hash HASH ffffffffff700120 000120 000038
1417 [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8
1419 [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0
1422 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1424 if (address_in_mem_range (li
->l_ld
, &vsyscall_range
))
1438 /* Get the address of the link_map for a given OBJFILE. */
1441 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
1443 struct svr4_info
*info
= get_svr4_info (objfile
->pspace
);
1445 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1446 if (info
->main_lm_addr
== 0)
1447 solib_add (NULL
, 0, auto_solib_add
);
1449 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1450 if (objfile
== current_program_space
->symfile_object_file
)
1451 return info
->main_lm_addr
;
1453 /* The other link map addresses may be found by examining the list
1454 of shared libraries. */
1455 for (struct so_list
*so
: current_program_space
->solibs ())
1456 if (so
->objfile
== objfile
)
1458 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1467 /* On some systems, the only way to recognize the link map entry for
1468 the main executable file is by looking at its name. Return
1469 non-zero iff SONAME matches one of the known main executable names. */
1472 match_main (const char *soname
)
1474 const char * const *mainp
;
1476 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
1478 if (strcmp (soname
, *mainp
) == 0)
1485 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1486 SVR4 run time loader. */
1489 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
1491 struct svr4_info
*info
= get_svr4_info (current_program_space
);
1493 return ((pc
>= info
->interp_text_sect_low
1494 && pc
< info
->interp_text_sect_high
)
1495 || (pc
>= info
->interp_plt_sect_low
1496 && pc
< info
->interp_plt_sect_high
)
1497 || in_plt_section (pc
)
1498 || in_gnu_ifunc_stub (pc
));
1501 /* Given an executable's ABFD and target, compute the entry-point
1505 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
1509 /* KevinB wrote ... for most targets, the address returned by
1510 bfd_get_start_address() is the entry point for the start
1511 function. But, for some targets, bfd_get_start_address() returns
1512 the address of a function descriptor from which the entry point
1513 address may be extracted. This address is extracted by
1514 gdbarch_convert_from_func_ptr_addr(). The method
1515 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1516 function for targets which don't use function descriptors. */
1517 addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
1518 bfd_get_start_address (abfd
),
1520 return gdbarch_addr_bits_remove (target_gdbarch (), addr
);
1523 /* A probe and its associated action. */
1525 struct probe_and_action
1530 /* The relocated address of the probe. */
1534 enum probe_action action
;
1536 /* The objfile where this probe was found. */
1537 struct objfile
*objfile
;
1540 /* Returns a hash code for the probe_and_action referenced by p. */
1543 hash_probe_and_action (const void *p
)
1545 const struct probe_and_action
*pa
= (const struct probe_and_action
*) p
;
1547 return (hashval_t
) pa
->address
;
1550 /* Returns non-zero if the probe_and_actions referenced by p1 and p2
1554 equal_probe_and_action (const void *p1
, const void *p2
)
1556 const struct probe_and_action
*pa1
= (const struct probe_and_action
*) p1
;
1557 const struct probe_and_action
*pa2
= (const struct probe_and_action
*) p2
;
1559 return pa1
->address
== pa2
->address
;
1562 /* Traversal function for probes_table_remove_objfile_probes. */
1565 probes_table_htab_remove_objfile_probes (void **slot
, void *info
)
1567 probe_and_action
*pa
= (probe_and_action
*) *slot
;
1568 struct objfile
*objfile
= (struct objfile
*) info
;
1570 if (pa
->objfile
== objfile
)
1571 htab_clear_slot (get_svr4_info (objfile
->pspace
)->probes_table
.get (),
1577 /* Remove all probes that belong to OBJFILE from the probes table. */
1580 probes_table_remove_objfile_probes (struct objfile
*objfile
)
1582 svr4_info
*info
= get_svr4_info (objfile
->pspace
);
1583 if (info
->probes_table
!= nullptr)
1584 htab_traverse_noresize (info
->probes_table
.get (),
1585 probes_table_htab_remove_objfile_probes
, objfile
);
1588 /* Register a solib event probe and its associated action in the
1592 register_solib_event_probe (svr4_info
*info
, struct objfile
*objfile
,
1593 probe
*prob
, CORE_ADDR address
,
1594 enum probe_action action
)
1596 struct probe_and_action lookup
, *pa
;
1599 /* Create the probes table, if necessary. */
1600 if (info
->probes_table
== NULL
)
1601 info
->probes_table
.reset (htab_create_alloc (1, hash_probe_and_action
,
1602 equal_probe_and_action
,
1603 xfree
, xcalloc
, xfree
));
1605 lookup
.address
= address
;
1606 slot
= htab_find_slot (info
->probes_table
.get (), &lookup
, INSERT
);
1607 gdb_assert (*slot
== HTAB_EMPTY_ENTRY
);
1609 pa
= XCNEW (struct probe_and_action
);
1611 pa
->address
= address
;
1612 pa
->action
= action
;
1613 pa
->objfile
= objfile
;
1618 /* Get the solib event probe at the specified location, and the
1619 action associated with it. Returns NULL if no solib event probe
1622 static struct probe_and_action
*
1623 solib_event_probe_at (struct svr4_info
*info
, CORE_ADDR address
)
1625 struct probe_and_action lookup
;
1628 lookup
.address
= address
;
1629 slot
= htab_find_slot (info
->probes_table
.get (), &lookup
, NO_INSERT
);
1634 return (struct probe_and_action
*) *slot
;
1637 /* Decide what action to take when the specified solib event probe is
1640 static enum probe_action
1641 solib_event_probe_action (struct probe_and_action
*pa
)
1643 enum probe_action action
;
1644 unsigned probe_argc
= 0;
1645 frame_info_ptr frame
= get_current_frame ();
1647 action
= pa
->action
;
1648 if (action
== DO_NOTHING
|| action
== PROBES_INTERFACE_FAILED
)
1651 gdb_assert (action
== FULL_RELOAD
|| action
== UPDATE_OR_RELOAD
);
1653 /* Check that an appropriate number of arguments has been supplied.
1655 arg0: Lmid_t lmid (mandatory)
1656 arg1: struct r_debug *debug_base (mandatory)
1657 arg2: struct link_map *new (optional, for incremental updates) */
1660 probe_argc
= pa
->prob
->get_argument_count (get_frame_arch (frame
));
1662 catch (const gdb_exception_error
&ex
)
1664 exception_print (gdb_stderr
, ex
);
1668 /* If get_argument_count throws an exception, probe_argc will be set
1669 to zero. However, if pa->prob does not have arguments, then
1670 get_argument_count will succeed but probe_argc will also be zero.
1671 Both cases happen because of different things, but they are
1672 treated equally here: action will be set to
1673 PROBES_INTERFACE_FAILED. */
1674 if (probe_argc
== 2)
1675 action
= FULL_RELOAD
;
1676 else if (probe_argc
< 2)
1677 action
= PROBES_INTERFACE_FAILED
;
1682 /* Populate the shared object list by reading the entire list of
1683 shared objects from the inferior. Handle special cases relating
1684 to the first elements of the list. Returns nonzero on success. */
1687 solist_update_full (struct svr4_info
*info
)
1689 free_solib_list (info
);
1690 info
->solib_list
= svr4_current_sos_direct (info
);
1695 /* Update the shared object list starting from the link-map entry
1696 passed by the linker in the probe's third argument. Returns
1697 nonzero if the list was successfully updated, or zero to indicate
1701 solist_update_incremental (struct svr4_info
*info
, CORE_ADDR lm
)
1703 struct so_list
*tail
;
1706 /* svr4_current_sos_direct contains logic to handle a number of
1707 special cases relating to the first elements of the list. To
1708 avoid duplicating this logic we defer to solist_update_full
1709 if the list is empty. */
1710 if (info
->solib_list
== NULL
)
1713 /* Fall back to a full update if we are using a remote target
1714 that does not support incremental transfers. */
1715 if (info
->using_xfer
&& !target_augmented_libraries_svr4_read ())
1718 /* Walk to the end of the list. */
1719 for (tail
= info
->solib_list
; tail
->next
!= NULL
; tail
= tail
->next
)
1722 lm_info_svr4
*li
= (lm_info_svr4
*) tail
->lm_info
;
1723 prev_lm
= li
->lm_addr
;
1725 /* Read the new objects. */
1726 if (info
->using_xfer
)
1728 struct svr4_library_list library_list
;
1731 xsnprintf (annex
, sizeof (annex
), "start=%s;prev=%s",
1732 phex_nz (lm
, sizeof (lm
)),
1733 phex_nz (prev_lm
, sizeof (prev_lm
)));
1734 if (!svr4_current_sos_via_xfer_libraries (&library_list
, annex
))
1737 tail
->next
= library_list
.head
;
1741 struct so_list
**link
= &tail
->next
;
1743 /* IGNORE_FIRST may safely be set to zero here because the
1744 above check and deferral to solist_update_full ensures
1745 that this call to svr4_read_so_list will never see the
1747 if (!svr4_read_so_list (info
, lm
, prev_lm
, &link
, 0))
1754 /* Disable the probes-based linker interface and revert to the
1755 original interface. We don't reset the breakpoints as the
1756 ones set up for the probes-based interface are adequate. */
1759 disable_probes_interface (svr4_info
*info
)
1761 warning (_("Probes-based dynamic linker interface failed.\n"
1762 "Reverting to original interface."));
1764 free_probes_table (info
);
1765 free_solib_list (info
);
1768 /* Update the solib list as appropriate when using the
1769 probes-based linker interface. Do nothing if using the
1770 standard interface. */
1773 svr4_handle_solib_event (void)
1775 struct svr4_info
*info
= get_svr4_info (current_program_space
);
1776 struct probe_and_action
*pa
;
1777 enum probe_action action
;
1778 struct value
*val
= NULL
;
1779 CORE_ADDR pc
, debug_base
, lm
= 0;
1780 frame_info_ptr frame
= get_current_frame ();
1782 /* Do nothing if not using the probes interface. */
1783 if (info
->probes_table
== NULL
)
1786 /* If anything goes wrong we revert to the original linker
1788 auto cleanup
= make_scope_exit ([info
] ()
1790 disable_probes_interface (info
);
1793 pc
= regcache_read_pc (get_current_regcache ());
1794 pa
= solib_event_probe_at (info
, pc
);
1798 action
= solib_event_probe_action (pa
);
1799 if (action
== PROBES_INTERFACE_FAILED
)
1802 if (action
== DO_NOTHING
)
1808 /* evaluate_argument looks up symbols in the dynamic linker
1809 using find_pc_section. find_pc_section is accelerated by a cache
1810 called the section map. The section map is invalidated every
1811 time a shared library is loaded or unloaded, and if the inferior
1812 is generating a lot of shared library events then the section map
1813 will be updated every time svr4_handle_solib_event is called.
1814 We called find_pc_section in svr4_create_solib_event_breakpoints,
1815 so we can guarantee that the dynamic linker's sections are in the
1816 section map. We can therefore inhibit section map updates across
1817 these calls to evaluate_argument and save a lot of time. */
1819 scoped_restore inhibit_updates
1820 = inhibit_section_map_updates (current_program_space
);
1824 val
= pa
->prob
->evaluate_argument (1, frame
);
1826 catch (const gdb_exception_error
&ex
)
1828 exception_print (gdb_stderr
, ex
);
1835 debug_base
= value_as_address (val
);
1836 if (debug_base
== 0)
1839 /* Always locate the debug struct, in case it moved. */
1840 info
->debug_base
= 0;
1841 if (locate_base (info
) == 0)
1843 /* It's possible for the reloc_complete probe to be triggered before
1844 the linker has set the DT_DEBUG pointer (for example, when the
1845 linker has finished relocating an LD_AUDIT library or its
1846 dependencies). Since we can't yet handle libraries from other link
1847 namespaces, we don't lose anything by ignoring them here. */
1848 struct value
*link_map_id_val
;
1851 link_map_id_val
= pa
->prob
->evaluate_argument (0, frame
);
1853 catch (const gdb_exception_error
)
1855 link_map_id_val
= NULL
;
1857 /* glibc and illumos' libc both define LM_ID_BASE as zero. */
1858 if (link_map_id_val
!= NULL
&& value_as_long (link_map_id_val
) != 0)
1859 action
= DO_NOTHING
;
1864 /* GDB does not currently support libraries loaded via dlmopen
1865 into namespaces other than the initial one. We must ignore
1866 any namespace other than the initial namespace here until
1867 support for this is added to GDB. */
1868 if (debug_base
!= info
->debug_base
)
1869 action
= DO_NOTHING
;
1871 if (action
== UPDATE_OR_RELOAD
)
1875 val
= pa
->prob
->evaluate_argument (2, frame
);
1877 catch (const gdb_exception_error
&ex
)
1879 exception_print (gdb_stderr
, ex
);
1884 lm
= value_as_address (val
);
1887 action
= FULL_RELOAD
;
1890 /* Resume section map updates. Closing the scope is
1894 if (action
== UPDATE_OR_RELOAD
)
1896 if (!solist_update_incremental (info
, lm
))
1897 action
= FULL_RELOAD
;
1900 if (action
== FULL_RELOAD
)
1902 if (!solist_update_full (info
))
1909 /* Helper function for svr4_update_solib_event_breakpoints. */
1912 svr4_update_solib_event_breakpoint (struct breakpoint
*b
)
1914 if (b
->type
!= bp_shlib_event
)
1916 /* Continue iterating. */
1920 for (bp_location
*loc
: b
->locations ())
1922 struct svr4_info
*info
;
1923 struct probe_and_action
*pa
;
1925 info
= solib_svr4_pspace_data
.get (loc
->pspace
);
1926 if (info
== NULL
|| info
->probes_table
== NULL
)
1929 pa
= solib_event_probe_at (info
, loc
->address
);
1933 if (pa
->action
== DO_NOTHING
)
1935 if (b
->enable_state
== bp_disabled
&& stop_on_solib_events
)
1936 enable_breakpoint (b
);
1937 else if (b
->enable_state
== bp_enabled
&& !stop_on_solib_events
)
1938 disable_breakpoint (b
);
1944 /* Continue iterating. */
1948 /* Enable or disable optional solib event breakpoints as appropriate.
1949 Called whenever stop_on_solib_events is changed. */
1952 svr4_update_solib_event_breakpoints (void)
1954 for (breakpoint
*bp
: all_breakpoints_safe ())
1955 svr4_update_solib_event_breakpoint (bp
);
1958 /* Create and register solib event breakpoints. PROBES is an array
1959 of NUM_PROBES elements, each of which is vector of probes. A
1960 solib event breakpoint will be created and registered for each
1964 svr4_create_probe_breakpoints (svr4_info
*info
, struct gdbarch
*gdbarch
,
1965 const std::vector
<probe
*> *probes
,
1966 struct objfile
*objfile
)
1968 for (int i
= 0; i
< NUM_PROBES
; i
++)
1970 enum probe_action action
= probe_info
[i
].action
;
1972 for (probe
*p
: probes
[i
])
1974 CORE_ADDR address
= p
->get_relocated_address (objfile
);
1976 create_solib_event_breakpoint (gdbarch
, address
);
1977 register_solib_event_probe (info
, objfile
, p
, address
, action
);
1981 svr4_update_solib_event_breakpoints ();
1984 /* Find all the glibc named probes. Only if all of the probes are found, then
1985 create them and return true. Otherwise return false. If WITH_PREFIX is set
1986 then add "rtld" to the front of the probe names. */
1988 svr4_find_and_create_probe_breakpoints (svr4_info
*info
,
1989 struct gdbarch
*gdbarch
,
1990 struct obj_section
*os
,
1993 std::vector
<probe
*> probes
[NUM_PROBES
];
1995 for (int i
= 0; i
< NUM_PROBES
; i
++)
1997 const char *name
= probe_info
[i
].name
;
2000 /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4 shipped with an early
2001 version of the probes code in which the probes' names were prefixed
2002 with "rtld_" and the "map_failed" probe did not exist. The locations
2003 of the probes are otherwise the same, so we check for probes with
2004 prefixed names if probes with unprefixed names are not present. */
2007 xsnprintf (buf
, sizeof (buf
), "rtld_%s", name
);
2011 probes
[i
] = find_probes_in_objfile (os
->objfile
, "rtld", name
);
2013 /* The "map_failed" probe did not exist in early
2014 versions of the probes code in which the probes'
2015 names were prefixed with "rtld_". */
2016 if (with_prefix
&& streq (name
, "rtld_map_failed"))
2019 /* Ensure at least one probe for the current name was found. */
2020 if (probes
[i
].empty ())
2023 /* Ensure probe arguments can be evaluated. */
2024 for (probe
*p
: probes
[i
])
2026 if (!p
->can_evaluate_arguments ())
2028 /* This will fail if the probe is invalid. This has been seen on Arm
2029 due to references to symbols that have been resolved away. */
2032 p
->get_argument_count (gdbarch
);
2034 catch (const gdb_exception_error
&ex
)
2036 exception_print (gdb_stderr
, ex
);
2037 warning (_("Initializing probes-based dynamic linker interface "
2038 "failed.\nReverting to original interface."));
2044 /* All probes found. Now create them. */
2045 svr4_create_probe_breakpoints (info
, gdbarch
, probes
, os
->objfile
);
2049 /* Both the SunOS and the SVR4 dynamic linkers call a marker function
2050 before and after mapping and unmapping shared libraries. The sole
2051 purpose of this method is to allow debuggers to set a breakpoint so
2052 they can track these changes.
2054 Some versions of the glibc dynamic linker contain named probes
2055 to allow more fine grained stopping. Given the address of the
2056 original marker function, this function attempts to find these
2057 probes, and if found, sets breakpoints on those instead. If the
2058 probes aren't found, a single breakpoint is set on the original
2062 svr4_create_solib_event_breakpoints (svr4_info
*info
, struct gdbarch
*gdbarch
,
2065 struct obj_section
*os
= find_pc_section (address
);
2068 || (!svr4_find_and_create_probe_breakpoints (info
, gdbarch
, os
, false)
2069 && !svr4_find_and_create_probe_breakpoints (info
, gdbarch
, os
, true)))
2070 create_solib_event_breakpoint (gdbarch
, address
);
2073 /* Helper function for gdb_bfd_lookup_symbol. */
2076 cmp_name_and_sec_flags (const asymbol
*sym
, const void *data
)
2078 return (strcmp (sym
->name
, (const char *) data
) == 0
2079 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0);
2081 /* Arrange for dynamic linker to hit breakpoint.
2083 Both the SunOS and the SVR4 dynamic linkers have, as part of their
2084 debugger interface, support for arranging for the inferior to hit
2085 a breakpoint after mapping in the shared libraries. This function
2086 enables that breakpoint.
2088 For SunOS, there is a special flag location (in_debugger) which we
2089 set to 1. When the dynamic linker sees this flag set, it will set
2090 a breakpoint at a location known only to itself, after saving the
2091 original contents of that place and the breakpoint address itself,
2092 in it's own internal structures. When we resume the inferior, it
2093 will eventually take a SIGTRAP when it runs into the breakpoint.
2094 We handle this (in a different place) by restoring the contents of
2095 the breakpointed location (which is only known after it stops),
2096 chasing around to locate the shared libraries that have been
2097 loaded, then resuming.
2099 For SVR4, the debugger interface structure contains a member (r_brk)
2100 which is statically initialized at the time the shared library is
2101 built, to the offset of a function (_r_debug_state) which is guaran-
2102 teed to be called once before mapping in a library, and again when
2103 the mapping is complete. At the time we are examining this member,
2104 it contains only the unrelocated offset of the function, so we have
2105 to do our own relocation. Later, when the dynamic linker actually
2106 runs, it relocates r_brk to be the actual address of _r_debug_state().
2108 The debugger interface structure also contains an enumeration which
2109 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
2110 depending upon whether or not the library is being mapped or unmapped,
2111 and then set to RT_CONSISTENT after the library is mapped/unmapped. */
2114 enable_break (struct svr4_info
*info
, int from_tty
)
2116 struct bound_minimal_symbol msymbol
;
2117 const char * const *bkpt_namep
;
2118 asection
*interp_sect
;
2121 info
->interp_text_sect_low
= info
->interp_text_sect_high
= 0;
2122 info
->interp_plt_sect_low
= info
->interp_plt_sect_high
= 0;
2124 /* If we already have a shared library list in the target, and
2125 r_debug contains r_brk, set the breakpoint there - this should
2126 mean r_brk has already been relocated. Assume the dynamic linker
2127 is the object containing r_brk. */
2129 solib_add (NULL
, from_tty
, auto_solib_add
);
2131 if (info
->debug_base
&& solib_svr4_r_map (info
) != 0)
2132 sym_addr
= solib_svr4_r_brk (info
);
2136 struct obj_section
*os
;
2138 sym_addr
= gdbarch_addr_bits_remove
2140 gdbarch_convert_from_func_ptr_addr
2141 (target_gdbarch (), sym_addr
, current_inferior ()->top_target ()));
2143 /* On at least some versions of Solaris there's a dynamic relocation
2144 on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
2145 we get control before the dynamic linker has self-relocated.
2146 Check if SYM_ADDR is in a known section, if it is assume we can
2147 trust its value. This is just a heuristic though, it could go away
2148 or be replaced if it's getting in the way.
2150 On ARM we need to know whether the ISA of rtld_db_dlactivity (or
2151 however it's spelled in your particular system) is ARM or Thumb.
2152 That knowledge is encoded in the address, if it's Thumb the low bit
2153 is 1. However, we've stripped that info above and it's not clear
2154 what all the consequences are of passing a non-addr_bits_remove'd
2155 address to svr4_create_solib_event_breakpoints. The call to
2156 find_pc_section verifies we know about the address and have some
2157 hope of computing the right kind of breakpoint to use (via
2158 symbol info). It does mean that GDB needs to be pointed at a
2159 non-stripped version of the dynamic linker in order to obtain
2160 information it already knows about. Sigh. */
2162 os
= find_pc_section (sym_addr
);
2165 /* Record the relocated start and end address of the dynamic linker
2166 text and plt section for svr4_in_dynsym_resolve_code. */
2168 CORE_ADDR load_addr
;
2170 tmp_bfd
= os
->objfile
->obfd
.get ();
2171 load_addr
= os
->objfile
->text_section_offset ();
2173 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
2176 info
->interp_text_sect_low
2177 = bfd_section_vma (interp_sect
) + load_addr
;
2178 info
->interp_text_sect_high
2179 = info
->interp_text_sect_low
+ bfd_section_size (interp_sect
);
2181 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
2184 info
->interp_plt_sect_low
2185 = bfd_section_vma (interp_sect
) + load_addr
;
2186 info
->interp_plt_sect_high
2187 = info
->interp_plt_sect_low
+ bfd_section_size (interp_sect
);
2190 svr4_create_solib_event_breakpoints (info
, target_gdbarch (), sym_addr
);
2195 /* Find the program interpreter; if not found, warn the user and drop
2196 into the old breakpoint at symbol code. */
2197 gdb::optional
<gdb::byte_vector
> interp_name_holder
2198 = find_program_interpreter ();
2199 if (interp_name_holder
)
2201 const char *interp_name
= (const char *) interp_name_holder
->data ();
2202 CORE_ADDR load_addr
= 0;
2203 int load_addr_found
= 0;
2204 int loader_found_in_list
= 0;
2205 struct target_ops
*tmp_bfd_target
;
2209 /* Now we need to figure out where the dynamic linker was
2210 loaded so that we can load its symbols and place a breakpoint
2211 in the dynamic linker itself.
2213 This address is stored on the stack. However, I've been unable
2214 to find any magic formula to find it for Solaris (appears to
2215 be trivial on GNU/Linux). Therefore, we have to try an alternate
2216 mechanism to find the dynamic linker's base address. */
2218 gdb_bfd_ref_ptr tmp_bfd
;
2221 tmp_bfd
= solib_bfd_open (interp_name
);
2223 catch (const gdb_exception
&ex
)
2227 if (tmp_bfd
== NULL
)
2228 goto bkpt_at_symbol
;
2230 /* Now convert the TMP_BFD into a target. That way target, as
2231 well as BFD operations can be used. */
2232 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
);
2234 /* On a running target, we can get the dynamic linker's base
2235 address from the shared library table. */
2236 for (struct so_list
*so
: current_program_space
->solibs ())
2238 if (svr4_same_1 (interp_name
, so
->so_original_name
))
2240 load_addr_found
= 1;
2241 loader_found_in_list
= 1;
2242 load_addr
= lm_addr_check (so
, tmp_bfd
.get ());
2247 /* If we were not able to find the base address of the loader
2248 from our so_list, then try using the AT_BASE auxilliary entry. */
2249 if (!load_addr_found
)
2250 if (target_auxv_search (AT_BASE
, &load_addr
) > 0)
2252 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
2254 /* Ensure LOAD_ADDR has proper sign in its possible upper bits so
2255 that `+ load_addr' will overflow CORE_ADDR width not creating
2256 invalid addresses like 0x101234567 for 32bit inferiors on 64bit
2259 if (addr_bit
< (sizeof (CORE_ADDR
) * HOST_CHAR_BIT
))
2261 CORE_ADDR space_size
= (CORE_ADDR
) 1 << addr_bit
;
2262 CORE_ADDR tmp_entry_point
= exec_entry_point (tmp_bfd
.get (),
2265 gdb_assert (load_addr
< space_size
);
2267 /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked
2268 64bit ld.so with 32bit executable, it should not happen. */
2270 if (tmp_entry_point
< space_size
2271 && tmp_entry_point
+ load_addr
>= space_size
)
2272 load_addr
-= space_size
;
2275 load_addr_found
= 1;
2278 /* Otherwise we find the dynamic linker's base address by examining
2279 the current pc (which should point at the entry point for the
2280 dynamic linker) and subtracting the offset of the entry point.
2282 This is more fragile than the previous approaches, but is a good
2283 fallback method because it has actually been working well in
2285 if (!load_addr_found
)
2287 struct regcache
*regcache
2288 = get_thread_arch_regcache (current_inferior ()->process_target (),
2289 inferior_ptid
, target_gdbarch ());
2291 load_addr
= (regcache_read_pc (regcache
)
2292 - exec_entry_point (tmp_bfd
.get (), tmp_bfd_target
));
2295 if (!loader_found_in_list
)
2297 info
->debug_loader_name
= xstrdup (interp_name
);
2298 info
->debug_loader_offset_p
= 1;
2299 info
->debug_loader_offset
= load_addr
;
2300 solib_add (NULL
, from_tty
, auto_solib_add
);
2303 /* Record the relocated start and end address of the dynamic linker
2304 text and plt section for svr4_in_dynsym_resolve_code. */
2305 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".text");
2308 info
->interp_text_sect_low
2309 = bfd_section_vma (interp_sect
) + load_addr
;
2310 info
->interp_text_sect_high
2311 = info
->interp_text_sect_low
+ bfd_section_size (interp_sect
);
2313 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".plt");
2316 info
->interp_plt_sect_low
2317 = bfd_section_vma (interp_sect
) + load_addr
;
2318 info
->interp_plt_sect_high
2319 = info
->interp_plt_sect_low
+ bfd_section_size (interp_sect
);
2322 /* Now try to set a breakpoint in the dynamic linker. */
2323 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2325 sym_addr
= gdb_bfd_lookup_symbol (tmp_bfd
.get (),
2326 cmp_name_and_sec_flags
,
2333 /* Convert 'sym_addr' from a function pointer to an address.
2334 Because we pass tmp_bfd_target instead of the current
2335 target, this will always produce an unrelocated value. */
2336 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2340 /* We're done with both the temporary bfd and target. Closing
2341 the target closes the underlying bfd, because it holds the
2342 only remaining reference. */
2343 target_close (tmp_bfd_target
);
2347 svr4_create_solib_event_breakpoints (info
, target_gdbarch (),
2348 load_addr
+ sym_addr
);
2352 /* For whatever reason we couldn't set a breakpoint in the dynamic
2353 linker. Warn and drop into the old code. */
2355 warning (_("Unable to find dynamic linker breakpoint function.\n"
2356 "GDB will be unable to debug shared library initializers\n"
2357 "and track explicitly loaded dynamic code."));
2360 /* Scan through the lists of symbols, trying to look up the symbol and
2361 set a breakpoint there. Terminate loop when we/if we succeed. */
2363 objfile
*objf
= current_program_space
->symfile_object_file
;
2364 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2366 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, objf
);
2367 if ((msymbol
.minsym
!= NULL
)
2368 && (msymbol
.value_address () != 0))
2370 sym_addr
= msymbol
.value_address ();
2371 sym_addr
= gdbarch_convert_from_func_ptr_addr
2372 (target_gdbarch (), sym_addr
, current_inferior ()->top_target ());
2373 svr4_create_solib_event_breakpoints (info
, target_gdbarch (),
2379 if (interp_name_holder
&& !current_inferior ()->attach_flag
)
2381 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2383 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, objf
);
2384 if ((msymbol
.minsym
!= NULL
)
2385 && (msymbol
.value_address () != 0))
2387 sym_addr
= msymbol
.value_address ();
2388 sym_addr
= gdbarch_convert_from_func_ptr_addr
2389 (target_gdbarch (), sym_addr
,
2390 current_inferior ()->top_target ());
2391 svr4_create_solib_event_breakpoints (info
, target_gdbarch (),
2400 /* Read the ELF program headers from ABFD. */
2402 static gdb::optional
<gdb::byte_vector
>
2403 read_program_headers_from_bfd (bfd
*abfd
)
2405 Elf_Internal_Ehdr
*ehdr
= elf_elfheader (abfd
);
2406 int phdrs_size
= ehdr
->e_phnum
* ehdr
->e_phentsize
;
2407 if (phdrs_size
== 0)
2410 gdb::byte_vector
buf (phdrs_size
);
2411 if (bfd_seek (abfd
, ehdr
->e_phoff
, SEEK_SET
) != 0
2412 || bfd_bread (buf
.data (), phdrs_size
, abfd
) != phdrs_size
)
2418 /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior
2419 exec_bfd. Otherwise return 0.
2421 We relocate all of the sections by the same amount. This
2422 behavior is mandated by recent editions of the System V ABI.
2423 According to the System V Application Binary Interface,
2424 Edition 4.1, page 5-5:
2426 ... Though the system chooses virtual addresses for
2427 individual processes, it maintains the segments' relative
2428 positions. Because position-independent code uses relative
2429 addressing between segments, the difference between
2430 virtual addresses in memory must match the difference
2431 between virtual addresses in the file. The difference
2432 between the virtual address of any segment in memory and
2433 the corresponding virtual address in the file is thus a
2434 single constant value for any one executable or shared
2435 object in a given process. This difference is the base
2436 address. One use of the base address is to relocate the
2437 memory image of the program during dynamic linking.
2439 The same language also appears in Edition 4.0 of the System V
2440 ABI and is left unspecified in some of the earlier editions.
2442 Decide if the objfile needs to be relocated. As indicated above, we will
2443 only be here when execution is stopped. But during attachment PC can be at
2444 arbitrary address therefore regcache_read_pc can be misleading (contrary to
2445 the auxv AT_ENTRY value). Moreover for executable with interpreter section
2446 regcache_read_pc would point to the interpreter and not the main executable.
2448 So, to summarize, relocations are necessary when the start address obtained
2449 from the executable is different from the address in auxv AT_ENTRY entry.
2451 [ The astute reader will note that we also test to make sure that
2452 the executable in question has the DYNAMIC flag set. It is my
2453 opinion that this test is unnecessary (undesirable even). It
2454 was added to avoid inadvertent relocation of an executable
2455 whose e_type member in the ELF header is not ET_DYN. There may
2456 be a time in the future when it is desirable to do relocations
2457 on other types of files as well in which case this condition
2458 should either be removed or modified to accomodate the new file
2459 type. - Kevin, Nov 2000. ] */
2462 svr4_exec_displacement (CORE_ADDR
*displacementp
)
2464 /* ENTRY_POINT is a possible function descriptor - before
2465 a call to gdbarch_convert_from_func_ptr_addr. */
2466 CORE_ADDR entry_point
, exec_displacement
;
2468 if (current_program_space
->exec_bfd () == NULL
)
2471 /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries
2472 being executed themselves and PIE (Position Independent Executable)
2473 executables are ET_DYN. */
2475 if ((bfd_get_file_flags (current_program_space
->exec_bfd ()) & DYNAMIC
) == 0)
2478 if (target_auxv_search (AT_ENTRY
, &entry_point
) <= 0)
2482 = entry_point
- bfd_get_start_address (current_program_space
->exec_bfd ());
2484 /* Verify the EXEC_DISPLACEMENT candidate complies with the required page
2485 alignment. It is cheaper than the program headers comparison below. */
2487 if (bfd_get_flavour (current_program_space
->exec_bfd ())
2488 == bfd_target_elf_flavour
)
2490 const struct elf_backend_data
*elf
2491 = get_elf_backend_data (current_program_space
->exec_bfd ());
2493 /* p_align of PT_LOAD segments does not specify any alignment but
2494 only congruency of addresses:
2495 p_offset % p_align == p_vaddr % p_align
2496 Kernel is free to load the executable with lower alignment. */
2498 if ((exec_displacement
& (elf
->minpagesize
- 1)) != 0)
2502 /* Verify that the auxilliary vector describes the same file as exec_bfd, by
2503 comparing their program headers. If the program headers in the auxilliary
2504 vector do not match the program headers in the executable, then we are
2505 looking at a different file than the one used by the kernel - for
2506 instance, "gdb program" connected to "gdbserver :PORT ld.so program". */
2508 if (bfd_get_flavour (current_program_space
->exec_bfd ())
2509 == bfd_target_elf_flavour
)
2511 /* Be optimistic and return 0 only if GDB was able to verify the headers
2512 really do not match. */
2515 gdb::optional
<gdb::byte_vector
> phdrs_target
2516 = read_program_header (-1, &arch_size
, NULL
);
2517 gdb::optional
<gdb::byte_vector
> phdrs_binary
2518 = read_program_headers_from_bfd (current_program_space
->exec_bfd ());
2519 if (phdrs_target
&& phdrs_binary
)
2521 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
2523 /* We are dealing with three different addresses. EXEC_BFD
2524 represents current address in on-disk file. target memory content
2525 may be different from EXEC_BFD as the file may have been prelinked
2526 to a different address after the executable has been loaded.
2527 Moreover the address of placement in target memory can be
2528 different from what the program headers in target memory say -
2529 this is the goal of PIE.
2531 Detected DISPLACEMENT covers both the offsets of PIE placement and
2532 possible new prelink performed after start of the program. Here
2533 relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
2534 content offset for the verification purpose. */
2536 if (phdrs_target
->size () != phdrs_binary
->size ()
2537 || bfd_get_arch_size (current_program_space
->exec_bfd ()) != arch_size
)
2539 else if (arch_size
== 32
2540 && phdrs_target
->size () >= sizeof (Elf32_External_Phdr
)
2541 && phdrs_target
->size () % sizeof (Elf32_External_Phdr
) == 0)
2543 Elf_Internal_Ehdr
*ehdr2
2544 = elf_tdata (current_program_space
->exec_bfd ())->elf_header
;
2545 Elf_Internal_Phdr
*phdr2
2546 = elf_tdata (current_program_space
->exec_bfd ())->phdr
;
2547 CORE_ADDR displacement
= 0;
2550 /* DISPLACEMENT could be found more easily by the difference of
2551 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2552 already have enough information to compute that displacement
2553 with what we've read. */
2555 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2556 if (phdr2
[i
].p_type
== PT_LOAD
)
2558 Elf32_External_Phdr
*phdrp
;
2559 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2560 CORE_ADDR vaddr
, paddr
;
2561 CORE_ADDR displacement_vaddr
= 0;
2562 CORE_ADDR displacement_paddr
= 0;
2564 phdrp
= &((Elf32_External_Phdr
*) phdrs_target
->data ())[i
];
2565 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2566 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2568 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2570 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2572 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2574 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2576 if (displacement_vaddr
== displacement_paddr
)
2577 displacement
= displacement_vaddr
;
2582 /* Now compare program headers from the target and the binary
2583 with optional DISPLACEMENT. */
2586 i
< phdrs_target
->size () / sizeof (Elf32_External_Phdr
);
2589 Elf32_External_Phdr
*phdrp
;
2590 Elf32_External_Phdr
*phdr2p
;
2591 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2592 CORE_ADDR vaddr
, paddr
;
2593 asection
*plt2_asect
;
2595 phdrp
= &((Elf32_External_Phdr
*) phdrs_target
->data ())[i
];
2596 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2597 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2598 phdr2p
= &((Elf32_External_Phdr
*) phdrs_binary
->data ())[i
];
2600 /* PT_GNU_STACK is an exception by being never relocated by
2601 prelink as its addresses are always zero. */
2603 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2606 /* Check also other adjustment combinations - PR 11786. */
2608 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2610 vaddr
-= displacement
;
2611 store_unsigned_integer (buf_vaddr_p
, 4, byte_order
, vaddr
);
2613 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2615 paddr
-= displacement
;
2616 store_unsigned_integer (buf_paddr_p
, 4, byte_order
, paddr
);
2618 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2621 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2622 CentOS-5 has problems with filesz, memsz as well.
2623 Strip also modifies memsz of PT_TLS.
2625 if (phdr2
[i
].p_type
== PT_GNU_RELRO
2626 || phdr2
[i
].p_type
== PT_TLS
)
2628 Elf32_External_Phdr tmp_phdr
= *phdrp
;
2629 Elf32_External_Phdr tmp_phdr2
= *phdr2p
;
2631 memset (tmp_phdr
.p_filesz
, 0, 4);
2632 memset (tmp_phdr
.p_memsz
, 0, 4);
2633 memset (tmp_phdr
.p_flags
, 0, 4);
2634 memset (tmp_phdr
.p_align
, 0, 4);
2635 memset (tmp_phdr2
.p_filesz
, 0, 4);
2636 memset (tmp_phdr2
.p_memsz
, 0, 4);
2637 memset (tmp_phdr2
.p_flags
, 0, 4);
2638 memset (tmp_phdr2
.p_align
, 0, 4);
2640 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2645 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2646 bfd
*exec_bfd
= current_program_space
->exec_bfd ();
2647 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2651 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2654 content2
= (bfd_section_flags (plt2_asect
)
2655 & SEC_HAS_CONTENTS
) != 0;
2657 filesz
= extract_unsigned_integer (buf_filesz_p
, 4,
2660 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2661 FILESZ is from the in-memory image. */
2663 filesz
+= bfd_section_size (plt2_asect
);
2665 filesz
-= bfd_section_size (plt2_asect
);
2667 store_unsigned_integer (buf_filesz_p
, 4, byte_order
,
2670 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2677 else if (arch_size
== 64
2678 && phdrs_target
->size () >= sizeof (Elf64_External_Phdr
)
2679 && phdrs_target
->size () % sizeof (Elf64_External_Phdr
) == 0)
2681 Elf_Internal_Ehdr
*ehdr2
2682 = elf_tdata (current_program_space
->exec_bfd ())->elf_header
;
2683 Elf_Internal_Phdr
*phdr2
2684 = elf_tdata (current_program_space
->exec_bfd ())->phdr
;
2685 CORE_ADDR displacement
= 0;
2688 /* DISPLACEMENT could be found more easily by the difference of
2689 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2690 already have enough information to compute that displacement
2691 with what we've read. */
2693 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2694 if (phdr2
[i
].p_type
== PT_LOAD
)
2696 Elf64_External_Phdr
*phdrp
;
2697 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2698 CORE_ADDR vaddr
, paddr
;
2699 CORE_ADDR displacement_vaddr
= 0;
2700 CORE_ADDR displacement_paddr
= 0;
2702 phdrp
= &((Elf64_External_Phdr
*) phdrs_target
->data ())[i
];
2703 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2704 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2706 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2708 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2710 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2712 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2714 if (displacement_vaddr
== displacement_paddr
)
2715 displacement
= displacement_vaddr
;
2720 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2723 i
< phdrs_target
->size () / sizeof (Elf64_External_Phdr
);
2726 Elf64_External_Phdr
*phdrp
;
2727 Elf64_External_Phdr
*phdr2p
;
2728 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2729 CORE_ADDR vaddr
, paddr
;
2730 asection
*plt2_asect
;
2732 phdrp
= &((Elf64_External_Phdr
*) phdrs_target
->data ())[i
];
2733 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2734 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2735 phdr2p
= &((Elf64_External_Phdr
*) phdrs_binary
->data ())[i
];
2737 /* PT_GNU_STACK is an exception by being never relocated by
2738 prelink as its addresses are always zero. */
2740 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2743 /* Check also other adjustment combinations - PR 11786. */
2745 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2747 vaddr
-= displacement
;
2748 store_unsigned_integer (buf_vaddr_p
, 8, byte_order
, vaddr
);
2750 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2752 paddr
-= displacement
;
2753 store_unsigned_integer (buf_paddr_p
, 8, byte_order
, paddr
);
2755 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2758 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2759 CentOS-5 has problems with filesz, memsz as well.
2760 Strip also modifies memsz of PT_TLS.
2762 if (phdr2
[i
].p_type
== PT_GNU_RELRO
2763 || phdr2
[i
].p_type
== PT_TLS
)
2765 Elf64_External_Phdr tmp_phdr
= *phdrp
;
2766 Elf64_External_Phdr tmp_phdr2
= *phdr2p
;
2768 memset (tmp_phdr
.p_filesz
, 0, 8);
2769 memset (tmp_phdr
.p_memsz
, 0, 8);
2770 memset (tmp_phdr
.p_flags
, 0, 4);
2771 memset (tmp_phdr
.p_align
, 0, 8);
2772 memset (tmp_phdr2
.p_filesz
, 0, 8);
2773 memset (tmp_phdr2
.p_memsz
, 0, 8);
2774 memset (tmp_phdr2
.p_flags
, 0, 4);
2775 memset (tmp_phdr2
.p_align
, 0, 8);
2777 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2782 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2784 = bfd_get_section_by_name (current_program_space
->exec_bfd (),
2789 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2792 content2
= (bfd_section_flags (plt2_asect
)
2793 & SEC_HAS_CONTENTS
) != 0;
2795 filesz
= extract_unsigned_integer (buf_filesz_p
, 8,
2798 /* PLT2_ASECT is from on-disk file (current
2799 exec_bfd) while FILESZ is from the in-memory
2802 filesz
+= bfd_section_size (plt2_asect
);
2804 filesz
-= bfd_section_size (plt2_asect
);
2806 store_unsigned_integer (buf_filesz_p
, 8, byte_order
,
2809 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2823 /* It can be printed repeatedly as there is no easy way to check
2824 the executable symbols/file has been already relocated to
2827 gdb_printf (_("Using PIE (Position Independent Executable) "
2828 "displacement %s for \"%s\".\n"),
2829 paddress (target_gdbarch (), exec_displacement
),
2830 bfd_get_filename (current_program_space
->exec_bfd ()));
2833 *displacementp
= exec_displacement
;
2837 /* Relocate the main executable. This function should be called upon
2838 stopping the inferior process at the entry point to the program.
2839 The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
2840 different, the main executable is relocated by the proper amount. */
2843 svr4_relocate_main_executable (void)
2845 CORE_ADDR displacement
;
2847 /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS
2848 probably contains the offsets computed using the PIE displacement
2849 from the previous run, which of course are irrelevant for this run.
2850 So we need to determine the new PIE displacement and recompute the
2851 section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS
2852 already contains pre-computed offsets.
2854 If we cannot compute the PIE displacement, either:
2856 - The executable is not PIE.
2858 - SYMFILE_OBJFILE does not match the executable started in the target.
2859 This can happen for main executable symbols loaded at the host while
2860 `ld.so --ld-args main-executable' is loaded in the target.
2862 Then we leave the section offsets untouched and use them as is for
2865 - These section offsets were properly reset earlier, and thus
2866 already contain the correct values. This can happen for instance
2867 when reconnecting via the remote protocol to a target that supports
2868 the `qOffsets' packet.
2870 - The section offsets were not reset earlier, and the best we can
2871 hope is that the old offsets are still applicable to the new run. */
2873 if (! svr4_exec_displacement (&displacement
))
2876 /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file
2879 objfile
*objf
= current_program_space
->symfile_object_file
;
2882 section_offsets
new_offsets (objf
->section_offsets
.size (),
2884 objfile_relocate (objf
, new_offsets
);
2886 else if (current_program_space
->exec_bfd ())
2890 bfd
*exec_bfd
= current_program_space
->exec_bfd ();
2891 for (asect
= exec_bfd
->sections
; asect
!= NULL
; asect
= asect
->next
)
2892 exec_set_section_address (bfd_get_filename (exec_bfd
), asect
->index
,
2893 bfd_section_vma (asect
) + displacement
);
2897 /* Implement the "create_inferior_hook" target_solib_ops method.
2899 For SVR4 executables, this first instruction is either the first
2900 instruction in the dynamic linker (for dynamically linked
2901 executables) or the instruction at "start" for statically linked
2902 executables. For dynamically linked executables, the system
2903 first exec's /lib/libc.so.N, which contains the dynamic linker,
2904 and starts it running. The dynamic linker maps in any needed
2905 shared libraries, maps in the actual user executable, and then
2906 jumps to "start" in the user executable.
2908 We can arrange to cooperate with the dynamic linker to discover the
2909 names of shared libraries that are dynamically linked, and the base
2910 addresses to which they are linked.
2912 This function is responsible for discovering those names and
2913 addresses, and saving sufficient information about them to allow
2914 their symbols to be read at a later time. */
2917 svr4_solib_create_inferior_hook (int from_tty
)
2919 struct svr4_info
*info
;
2921 info
= get_svr4_info (current_program_space
);
2923 /* Clear the probes-based interface's state. */
2924 free_probes_table (info
);
2925 free_solib_list (info
);
2927 /* Relocate the main executable if necessary. */
2928 svr4_relocate_main_executable ();
2930 /* No point setting a breakpoint in the dynamic linker if we can't
2931 hit it (e.g., a core file, or a trace file). */
2932 if (!target_has_execution ())
2935 if (!svr4_have_link_map_offsets ())
2938 if (!enable_break (info
, from_tty
))
2943 svr4_clear_solib (void)
2945 struct svr4_info
*info
;
2947 info
= get_svr4_info (current_program_space
);
2948 info
->debug_base
= 0;
2949 info
->debug_loader_offset_p
= 0;
2950 info
->debug_loader_offset
= 0;
2951 xfree (info
->debug_loader_name
);
2952 info
->debug_loader_name
= NULL
;
2955 /* Clear any bits of ADDR that wouldn't fit in a target-format
2956 data pointer. "Data pointer" here refers to whatever sort of
2957 address the dynamic linker uses to manage its sections. At the
2958 moment, we don't support shared libraries on any processors where
2959 code and data pointers are different sizes.
2961 This isn't really the right solution. What we really need here is
2962 a way to do arithmetic on CORE_ADDR values that respects the
2963 natural pointer/address correspondence. (For example, on the MIPS,
2964 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
2965 sign-extend the value. There, simply truncating the bits above
2966 gdbarch_ptr_bit, as we do below, is no good.) This should probably
2967 be a new gdbarch method or something. */
2969 svr4_truncate_ptr (CORE_ADDR addr
)
2971 if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR
) * 8)
2972 /* We don't need to truncate anything, and the bit twiddling below
2973 will fail due to overflow problems. */
2976 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1);
2981 svr4_relocate_section_addresses (struct so_list
*so
,
2982 struct target_section
*sec
)
2984 bfd
*abfd
= sec
->the_bfd_section
->owner
;
2986 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ lm_addr_check (so
, abfd
));
2987 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ lm_addr_check (so
, abfd
));
2991 /* Architecture-specific operations. */
2993 struct solib_svr4_ops
2995 /* Return a description of the layout of `struct link_map'. */
2996 struct link_map_offsets
*(*fetch_link_map_offsets
)(void) = nullptr;
2999 /* Per-architecture data key. */
3000 static const registry
<gdbarch
>::key
<struct solib_svr4_ops
> solib_svr4_data
;
3002 /* Return a default for the architecture-specific operations. */
3004 static struct solib_svr4_ops
*
3005 get_ops (struct gdbarch
*gdbarch
)
3007 struct solib_svr4_ops
*ops
= solib_svr4_data
.get (gdbarch
);
3009 ops
= solib_svr4_data
.emplace (gdbarch
);
3013 /* Set the architecture-specific `struct link_map_offsets' fetcher for
3014 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
3017 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
3018 struct link_map_offsets
*(*flmo
) (void))
3020 struct solib_svr4_ops
*ops
= get_ops (gdbarch
);
3022 ops
->fetch_link_map_offsets
= flmo
;
3024 set_gdbarch_so_ops (gdbarch
, &svr4_so_ops
);
3025 set_gdbarch_iterate_over_objfiles_in_search_order
3026 (gdbarch
, svr4_iterate_over_objfiles_in_search_order
);
3029 /* Fetch a link_map_offsets structure using the architecture-specific
3030 `struct link_map_offsets' fetcher. */
3032 static struct link_map_offsets
*
3033 svr4_fetch_link_map_offsets (void)
3035 struct solib_svr4_ops
*ops
= get_ops (target_gdbarch ());
3037 gdb_assert (ops
->fetch_link_map_offsets
);
3038 return ops
->fetch_link_map_offsets ();
3041 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
3044 svr4_have_link_map_offsets (void)
3046 struct solib_svr4_ops
*ops
= get_ops (target_gdbarch ());
3048 return (ops
->fetch_link_map_offsets
!= NULL
);
3052 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
3053 `struct r_debug' and a `struct link_map' that are binary compatible
3054 with the original SVR4 implementation. */
3056 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3057 for an ILP32 SVR4 system. */
3059 struct link_map_offsets
*
3060 svr4_ilp32_fetch_link_map_offsets (void)
3062 static struct link_map_offsets lmo
;
3063 static struct link_map_offsets
*lmp
= NULL
;
3069 lmo
.r_version_offset
= 0;
3070 lmo
.r_version_size
= 4;
3071 lmo
.r_map_offset
= 4;
3072 lmo
.r_brk_offset
= 8;
3073 lmo
.r_ldsomap_offset
= 20;
3075 /* Everything we need is in the first 20 bytes. */
3076 lmo
.link_map_size
= 20;
3077 lmo
.l_addr_offset
= 0;
3078 lmo
.l_name_offset
= 4;
3079 lmo
.l_ld_offset
= 8;
3080 lmo
.l_next_offset
= 12;
3081 lmo
.l_prev_offset
= 16;
3087 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3088 for an LP64 SVR4 system. */
3090 struct link_map_offsets
*
3091 svr4_lp64_fetch_link_map_offsets (void)
3093 static struct link_map_offsets lmo
;
3094 static struct link_map_offsets
*lmp
= NULL
;
3100 lmo
.r_version_offset
= 0;
3101 lmo
.r_version_size
= 4;
3102 lmo
.r_map_offset
= 8;
3103 lmo
.r_brk_offset
= 16;
3104 lmo
.r_ldsomap_offset
= 40;
3106 /* Everything we need is in the first 40 bytes. */
3107 lmo
.link_map_size
= 40;
3108 lmo
.l_addr_offset
= 0;
3109 lmo
.l_name_offset
= 8;
3110 lmo
.l_ld_offset
= 16;
3111 lmo
.l_next_offset
= 24;
3112 lmo
.l_prev_offset
= 32;
3119 /* Search order for ELF DSOs linked with -Bsymbolic. Those DSOs have a
3120 different rule for symbol lookup. The lookup begins here in the DSO, not in
3121 the main executable. */
3124 svr4_iterate_over_objfiles_in_search_order
3125 (gdbarch
*gdbarch
, iterate_over_objfiles_in_search_order_cb_ftype cb
,
3126 objfile
*current_objfile
)
3128 bool checked_current_objfile
= false;
3129 if (current_objfile
!= nullptr)
3133 if (current_objfile
->separate_debug_objfile_backlink
!= nullptr)
3134 current_objfile
= current_objfile
->separate_debug_objfile_backlink
;
3136 if (current_objfile
== current_program_space
->symfile_object_file
)
3137 abfd
= current_program_space
->exec_bfd ();
3139 abfd
= current_objfile
->obfd
.get ();
3142 && gdb_bfd_scan_elf_dyntag (DT_SYMBOLIC
, abfd
, nullptr, nullptr) == 1)
3144 checked_current_objfile
= true;
3145 if (cb (current_objfile
))
3150 for (objfile
*objfile
: current_program_space
->objfiles ())
3152 if (checked_current_objfile
&& objfile
== current_objfile
)
3159 const struct target_so_ops svr4_so_ops
=
3161 svr4_relocate_section_addresses
,
3165 svr4_solib_create_inferior_hook
,
3167 open_symbol_file_object
,
3168 svr4_in_dynsym_resolve_code
,
3172 svr4_keep_data_in_core
,
3173 svr4_update_solib_event_breakpoints
,
3174 svr4_handle_solib_event
,
3177 void _initialize_svr4_solib ();
3179 _initialize_svr4_solib ()
3181 gdb::observers::free_objfile
.attach (svr4_free_objfile_observer
,