1 /* Handle SVR4 shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "elf/external.h"
23 #include "elf/common.h"
35 #include "gdbthread.h"
40 #include "solib-svr4.h"
42 #include "bfd-target.h"
49 static struct link_map_offsets
*svr4_fetch_link_map_offsets (void);
50 static int svr4_have_link_map_offsets (void);
51 static void svr4_relocate_main_executable (void);
52 static void svr4_free_library_list (void *p_list
);
54 /* On SVR4 systems, a list of symbols in the dynamic linker where
55 GDB can try to place a breakpoint to monitor shared library
58 If none of these symbols are found, or other errors occur, then
59 SVR4 systems will fall back to using a symbol as the "startup
60 mapping complete" breakpoint address. */
62 static const char * const solib_break_names
[] =
68 "__dl_rtld_db_dlactivity",
74 static const char * const bkpt_names
[] =
82 static const char * const main_name_list
[] =
88 /* What to do when a probe stop occurs. */
92 /* Something went seriously wrong. Stop using probes and
93 revert to using the older interface. */
94 PROBES_INTERFACE_FAILED
,
96 /* No action is required. The shared object list is still
100 /* The shared object list should be reloaded entirely. */
103 /* Attempt to incrementally update the shared object list. If
104 the update fails or is not possible, fall back to reloading
109 /* A probe's name and its associated action. */
113 /* The name of the probe. */
116 /* What to do when a probe stop occurs. */
117 enum probe_action action
;
120 /* A list of named probes and their associated actions. If all
121 probes are present in the dynamic linker then the probes-based
122 interface will be used. */
124 static const struct probe_info probe_info
[] =
126 { "init_start", DO_NOTHING
},
127 { "init_complete", FULL_RELOAD
},
128 { "map_start", DO_NOTHING
},
129 { "map_failed", DO_NOTHING
},
130 { "reloc_complete", UPDATE_OR_RELOAD
},
131 { "unmap_start", DO_NOTHING
},
132 { "unmap_complete", FULL_RELOAD
},
135 #define NUM_PROBES ARRAY_SIZE (probe_info)
137 /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
138 the same shared library. */
141 svr4_same_1 (const char *gdb_so_name
, const char *inferior_so_name
)
143 if (strcmp (gdb_so_name
, inferior_so_name
) == 0)
146 /* On Solaris, when starting inferior we think that dynamic linker is
147 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
148 contains /lib/ld.so.1. Sometimes one file is a link to another, but
149 sometimes they have identical content, but are not linked to each
150 other. We don't restrict this check for Solaris, but the chances
151 of running into this situation elsewhere are very low. */
152 if (strcmp (gdb_so_name
, "/usr/lib/ld.so.1") == 0
153 && strcmp (inferior_so_name
, "/lib/ld.so.1") == 0)
156 /* Similarly, we observed the same issue with sparc64, but with
157 different locations. */
158 if (strcmp (gdb_so_name
, "/usr/lib/sparcv9/ld.so.1") == 0
159 && strcmp (inferior_so_name
, "/lib/sparcv9/ld.so.1") == 0)
166 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
168 return (svr4_same_1 (gdb
->so_original_name
, inferior
->so_original_name
));
171 static lm_info_svr4
*
172 lm_info_read (CORE_ADDR lm_addr
)
174 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
176 lm_info_svr4
*lm_info
;
177 struct cleanup
*back_to
;
179 lm
= (gdb_byte
*) xmalloc (lmo
->link_map_size
);
180 back_to
= make_cleanup (xfree
, lm
);
182 if (target_read_memory (lm_addr
, lm
, lmo
->link_map_size
) != 0)
184 warning (_("Error reading shared library list entry at %s"),
185 paddress (target_gdbarch (), lm_addr
)),
190 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
192 lm_info
= new lm_info_svr4
;
193 lm_info
->lm_addr
= lm_addr
;
195 lm_info
->l_addr_inferior
= extract_typed_address (&lm
[lmo
->l_addr_offset
],
197 lm_info
->l_ld
= extract_typed_address (&lm
[lmo
->l_ld_offset
], ptr_type
);
198 lm_info
->l_next
= extract_typed_address (&lm
[lmo
->l_next_offset
],
200 lm_info
->l_prev
= extract_typed_address (&lm
[lmo
->l_prev_offset
],
202 lm_info
->l_name
= extract_typed_address (&lm
[lmo
->l_name_offset
],
206 do_cleanups (back_to
);
212 has_lm_dynamic_from_link_map (void)
214 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
216 return lmo
->l_ld_offset
>= 0;
220 lm_addr_check (const struct so_list
*so
, bfd
*abfd
)
222 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
226 struct bfd_section
*dyninfo_sect
;
227 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
;
229 l_addr
= li
->l_addr_inferior
;
231 if (! abfd
|| ! has_lm_dynamic_from_link_map ())
234 l_dynaddr
= li
->l_ld
;
236 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
237 if (dyninfo_sect
== NULL
)
240 dynaddr
= bfd_section_vma (abfd
, dyninfo_sect
);
242 if (dynaddr
+ l_addr
!= l_dynaddr
)
244 CORE_ADDR align
= 0x1000;
245 CORE_ADDR minpagesize
= align
;
247 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
249 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
250 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
255 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
256 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
257 align
= phdr
[i
].p_align
;
259 minpagesize
= get_elf_backend_data (abfd
)->minpagesize
;
262 /* Turn it into a mask. */
265 /* If the changes match the alignment requirements, we
266 assume we're using a core file that was generated by the
267 same binary, just prelinked with a different base offset.
268 If it doesn't match, we may have a different binary, the
269 same binary with the dynamic table loaded at an unrelated
270 location, or anything, really. To avoid regressions,
271 don't adjust the base offset in the latter case, although
272 odds are that, if things really changed, debugging won't
275 One could expect more the condition
276 ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
277 but the one below is relaxed for PPC. The PPC kernel supports
278 either 4k or 64k page sizes. To be prepared for 64k pages,
279 PPC ELF files are built using an alignment requirement of 64k.
280 However, when running on a kernel supporting 4k pages, the memory
281 mapping of the library may not actually happen on a 64k boundary!
283 (In the usual case where (l_addr & align) == 0, this check is
284 equivalent to the possibly expected check above.)
286 Even on PPC it must be zero-aligned at least for MINPAGESIZE. */
288 l_addr
= l_dynaddr
- dynaddr
;
290 if ((l_addr
& (minpagesize
- 1)) == 0
291 && (l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
294 printf_unfiltered (_("Using PIC (Position Independent Code) "
295 "prelink displacement %s for \"%s\".\n"),
296 paddress (target_gdbarch (), l_addr
),
301 /* There is no way to verify the library file matches. prelink
302 can during prelinking of an unprelinked file (or unprelinking
303 of a prelinked file) shift the DYNAMIC segment by arbitrary
304 offset without any page size alignment. There is no way to
305 find out the ELF header and/or Program Headers for a limited
306 verification if it they match. One could do a verification
307 of the DYNAMIC segment. Still the found address is the best
308 one GDB could find. */
310 warning (_(".dynamic section for \"%s\" "
311 "is not at the expected address "
312 "(wrong library or version mismatch?)"), so
->so_name
);
324 /* Per pspace SVR4 specific data. */
328 CORE_ADDR debug_base
; /* Base of dynamic linker structures. */
330 /* Validity flag for debug_loader_offset. */
331 int debug_loader_offset_p
;
333 /* Load address for the dynamic linker, inferred. */
334 CORE_ADDR debug_loader_offset
;
336 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
337 char *debug_loader_name
;
339 /* Load map address for the main executable. */
340 CORE_ADDR main_lm_addr
;
342 CORE_ADDR interp_text_sect_low
;
343 CORE_ADDR interp_text_sect_high
;
344 CORE_ADDR interp_plt_sect_low
;
345 CORE_ADDR interp_plt_sect_high
;
347 /* Nonzero if the list of objects was last obtained from the target
348 via qXfer:libraries-svr4:read. */
351 /* Table of struct probe_and_action instances, used by the
352 probes-based interface to map breakpoint addresses to probes
353 and their associated actions. Lookup is performed using
354 probe_and_action->probe->address. */
357 /* List of objects loaded into the inferior, used by the probes-
359 struct so_list
*solib_list
;
362 /* Per-program-space data key. */
363 static const struct program_space_data
*solib_svr4_pspace_data
;
365 /* Free the probes table. */
368 free_probes_table (struct svr4_info
*info
)
370 if (info
->probes_table
== NULL
)
373 htab_delete (info
->probes_table
);
374 info
->probes_table
= NULL
;
377 /* Free the solib list. */
380 free_solib_list (struct svr4_info
*info
)
382 svr4_free_library_list (&info
->solib_list
);
383 info
->solib_list
= NULL
;
387 svr4_pspace_data_cleanup (struct program_space
*pspace
, void *arg
)
389 struct svr4_info
*info
= (struct svr4_info
*) arg
;
391 free_probes_table (info
);
392 free_solib_list (info
);
397 /* Get the current svr4 data. If none is found yet, add it now. This
398 function always returns a valid object. */
400 static struct svr4_info
*
403 struct svr4_info
*info
;
405 info
= (struct svr4_info
*) program_space_data (current_program_space
,
406 solib_svr4_pspace_data
);
410 info
= XCNEW (struct svr4_info
);
411 set_program_space_data (current_program_space
, solib_svr4_pspace_data
, info
);
415 /* Local function prototypes */
417 static int match_main (const char *);
419 /* Read program header TYPE from inferior memory. The header is found
420 by scanning the OS auxillary vector.
422 If TYPE == -1, return the program headers instead of the contents of
425 Return a pointer to allocated memory holding the program header contents,
426 or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the
427 size of those contents is returned to P_SECT_SIZE. Likewise, the target
428 architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE and
429 the base address of the section is returned in BASE_ADDR. */
432 read_program_header (int type
, int *p_sect_size
, int *p_arch_size
,
433 CORE_ADDR
*base_addr
)
435 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
436 CORE_ADDR at_phdr
, at_phent
, at_phnum
, pt_phdr
= 0;
437 int arch_size
, sect_size
;
442 /* Get required auxv elements from target. */
443 if (target_auxv_search (¤t_target
, AT_PHDR
, &at_phdr
) <= 0)
445 if (target_auxv_search (¤t_target
, AT_PHENT
, &at_phent
) <= 0)
447 if (target_auxv_search (¤t_target
, AT_PHNUM
, &at_phnum
) <= 0)
449 if (!at_phdr
|| !at_phnum
)
452 /* Determine ELF architecture type. */
453 if (at_phent
== sizeof (Elf32_External_Phdr
))
455 else if (at_phent
== sizeof (Elf64_External_Phdr
))
460 /* Find the requested segment. */
464 sect_size
= at_phent
* at_phnum
;
466 else if (arch_size
== 32)
468 Elf32_External_Phdr phdr
;
471 /* Search for requested PHDR. */
472 for (i
= 0; i
< at_phnum
; i
++)
476 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
477 (gdb_byte
*)&phdr
, sizeof (phdr
)))
480 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
483 if (p_type
== PT_PHDR
)
486 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
497 /* Retrieve address and size. */
498 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
500 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
505 Elf64_External_Phdr phdr
;
508 /* Search for requested PHDR. */
509 for (i
= 0; i
< at_phnum
; i
++)
513 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
514 (gdb_byte
*)&phdr
, sizeof (phdr
)))
517 p_type
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_type
,
520 if (p_type
== PT_PHDR
)
523 pt_phdr
= extract_unsigned_integer ((gdb_byte
*) phdr
.p_vaddr
,
534 /* Retrieve address and size. */
535 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
,
537 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
,
541 /* PT_PHDR is optional, but we really need it
542 for PIE to make this work in general. */
546 /* at_phdr is real address in memory. pt_phdr is what pheader says it is.
547 Relocation offset is the difference between the two. */
548 sect_addr
= sect_addr
+ (at_phdr
- pt_phdr
);
551 /* Read in requested program header. */
552 buf
= (gdb_byte
*) xmalloc (sect_size
);
553 if (target_read_memory (sect_addr
, buf
, sect_size
))
560 *p_arch_size
= arch_size
;
562 *p_sect_size
= sect_size
;
564 *base_addr
= sect_addr
;
570 /* Return program interpreter string. */
572 find_program_interpreter (void)
574 gdb_byte
*buf
= NULL
;
576 /* If we have an exec_bfd, use its section table. */
578 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
580 struct bfd_section
*interp_sect
;
582 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
583 if (interp_sect
!= NULL
)
585 int sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
587 buf
= (gdb_byte
*) xmalloc (sect_size
);
588 bfd_get_section_contents (exec_bfd
, interp_sect
, buf
, 0, sect_size
);
592 /* If we didn't find it, use the target auxillary vector. */
594 buf
= read_program_header (PT_INTERP
, NULL
, NULL
, NULL
);
600 /* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is
601 found, 1 is returned and the corresponding PTR is set. */
604 scan_dyntag (const int desired_dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
,
607 int arch_size
, step
, sect_size
;
609 CORE_ADDR dyn_ptr
, dyn_addr
;
610 gdb_byte
*bufend
, *bufstart
, *buf
;
611 Elf32_External_Dyn
*x_dynp_32
;
612 Elf64_External_Dyn
*x_dynp_64
;
613 struct bfd_section
*sect
;
614 struct target_section
*target_section
;
619 if (bfd_get_flavour (abfd
) != bfd_target_elf_flavour
)
622 arch_size
= bfd_get_arch_size (abfd
);
626 /* Find the start address of the .dynamic section. */
627 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
631 for (target_section
= current_target_sections
->sections
;
632 target_section
< current_target_sections
->sections_end
;
634 if (sect
== target_section
->the_bfd_section
)
636 if (target_section
< current_target_sections
->sections_end
)
637 dyn_addr
= target_section
->addr
;
640 /* ABFD may come from OBJFILE acting only as a symbol file without being
641 loaded into the target (see add_symbol_file_command). This case is
642 such fallback to the file VMA address without the possibility of
643 having the section relocated to its actual in-memory address. */
645 dyn_addr
= bfd_section_vma (abfd
, sect
);
648 /* Read in .dynamic from the BFD. We will get the actual value
649 from memory later. */
650 sect_size
= bfd_section_size (abfd
, sect
);
651 buf
= bufstart
= (gdb_byte
*) alloca (sect_size
);
652 if (!bfd_get_section_contents (abfd
, sect
,
656 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
657 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
658 : sizeof (Elf64_External_Dyn
);
659 for (bufend
= buf
+ sect_size
;
665 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
666 current_dyntag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
667 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
671 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
672 current_dyntag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
673 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
675 if (current_dyntag
== DT_NULL
)
677 if (current_dyntag
== desired_dyntag
)
679 /* If requested, try to read the runtime value of this .dynamic
683 struct type
*ptr_type
;
685 CORE_ADDR ptr_addr_1
;
687 ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
688 ptr_addr_1
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
689 if (target_read_memory (ptr_addr_1
, ptr_buf
, arch_size
/ 8) == 0)
690 dyn_ptr
= extract_typed_address (ptr_buf
, ptr_type
);
693 *ptr_addr
= dyn_addr
+ (buf
- bufstart
);
702 /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable,
703 found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1
704 is returned and the corresponding PTR is set. */
707 scan_dyntag_auxv (const int desired_dyntag
, CORE_ADDR
*ptr
,
710 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
711 int sect_size
, arch_size
, step
;
715 gdb_byte
*bufend
, *bufstart
, *buf
;
717 /* Read in .dynamic section. */
718 buf
= bufstart
= read_program_header (PT_DYNAMIC
, §_size
, &arch_size
,
723 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
724 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
725 : sizeof (Elf64_External_Dyn
);
726 for (bufend
= buf
+ sect_size
;
732 Elf32_External_Dyn
*dynp
= (Elf32_External_Dyn
*) buf
;
734 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
736 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
741 Elf64_External_Dyn
*dynp
= (Elf64_External_Dyn
*) buf
;
743 current_dyntag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
,
745 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
,
748 if (current_dyntag
== DT_NULL
)
751 if (current_dyntag
== desired_dyntag
)
757 *ptr_addr
= base_addr
+ buf
- bufstart
;
768 /* Locate the base address of dynamic linker structs for SVR4 elf
771 For SVR4 elf targets the address of the dynamic linker's runtime
772 structure is contained within the dynamic info section in the
773 executable file. The dynamic section is also mapped into the
774 inferior address space. Because the runtime loader fills in the
775 real address before starting the inferior, we have to read in the
776 dynamic info section from the inferior address space.
777 If there are any errors while trying to find the address, we
778 silently return 0, otherwise the found address is returned. */
781 elf_locate_base (void)
783 struct bound_minimal_symbol msymbol
;
784 CORE_ADDR dyn_ptr
, dyn_ptr_addr
;
786 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
787 instead of DT_DEBUG, although they sometimes contain an unused
789 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
, NULL
)
790 || scan_dyntag_auxv (DT_MIPS_RLD_MAP
, &dyn_ptr
, NULL
))
792 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
794 int pbuf_size
= TYPE_LENGTH (ptr_type
);
796 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
797 /* DT_MIPS_RLD_MAP contains a pointer to the address
798 of the dynamic link structure. */
799 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
801 return extract_typed_address (pbuf
, ptr_type
);
804 /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form
805 because of needing to support PIE. DT_MIPS_RLD_MAP will also exist
807 if (scan_dyntag (DT_MIPS_RLD_MAP_REL
, exec_bfd
, &dyn_ptr
, &dyn_ptr_addr
)
808 || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL
, &dyn_ptr
, &dyn_ptr_addr
))
810 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
812 int pbuf_size
= TYPE_LENGTH (ptr_type
);
814 pbuf
= (gdb_byte
*) alloca (pbuf_size
);
815 /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the
816 DT slot to the address of the dynamic link structure. */
817 if (target_read_memory (dyn_ptr
+ dyn_ptr_addr
, pbuf
, pbuf_size
))
819 return extract_typed_address (pbuf
, ptr_type
);
823 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
, NULL
)
824 || scan_dyntag_auxv (DT_DEBUG
, &dyn_ptr
, NULL
))
827 /* This may be a static executable. Look for the symbol
828 conventionally named _r_debug, as a last resort. */
829 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
830 if (msymbol
.minsym
!= NULL
)
831 return BMSYMBOL_VALUE_ADDRESS (msymbol
);
833 /* DT_DEBUG entry not found. */
837 /* Locate the base address of dynamic linker structs.
839 For both the SunOS and SVR4 shared library implementations, if the
840 inferior executable has been linked dynamically, there is a single
841 address somewhere in the inferior's data space which is the key to
842 locating all of the dynamic linker's runtime structures. This
843 address is the value of the debug base symbol. The job of this
844 function is to find and return that address, or to return 0 if there
845 is no such address (the executable is statically linked for example).
847 For SunOS, the job is almost trivial, since the dynamic linker and
848 all of it's structures are statically linked to the executable at
849 link time. Thus the symbol for the address we are looking for has
850 already been added to the minimal symbol table for the executable's
851 objfile at the time the symbol file's symbols were read, and all we
852 have to do is look it up there. Note that we explicitly do NOT want
853 to find the copies in the shared library.
855 The SVR4 version is a bit more complicated because the address
856 is contained somewhere in the dynamic info section. We have to go
857 to a lot more work to discover the address of the debug base symbol.
858 Because of this complexity, we cache the value we find and return that
859 value on subsequent invocations. Note there is no copy in the
860 executable symbol tables. */
863 locate_base (struct svr4_info
*info
)
865 /* Check to see if we have a currently valid address, and if so, avoid
866 doing all this work again and just return the cached address. If
867 we have no cached address, try to locate it in the dynamic info
868 section for ELF executables. There's no point in doing any of this
869 though if we don't have some link map offsets to work with. */
871 if (info
->debug_base
== 0 && svr4_have_link_map_offsets ())
872 info
->debug_base
= elf_locate_base ();
873 return info
->debug_base
;
876 /* Find the first element in the inferior's dynamic link map, and
877 return its address in the inferior. Return zero if the address
878 could not be determined.
880 FIXME: Perhaps we should validate the info somehow, perhaps by
881 checking r_version for a known version number, or r_state for
885 solib_svr4_r_map (struct svr4_info
*info
)
887 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
888 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
893 addr
= read_memory_typed_address (info
->debug_base
+ lmo
->r_map_offset
,
896 CATCH (ex
, RETURN_MASK_ERROR
)
898 exception_print (gdb_stderr
, ex
);
905 /* Find r_brk from the inferior's debug base. */
908 solib_svr4_r_brk (struct svr4_info
*info
)
910 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
911 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
913 return read_memory_typed_address (info
->debug_base
+ lmo
->r_brk_offset
,
917 /* Find the link map for the dynamic linker (if it is not in the
918 normal list of loaded shared objects). */
921 solib_svr4_r_ldsomap (struct svr4_info
*info
)
923 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
924 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
925 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
926 ULONGEST version
= 0;
930 /* Check version, and return zero if `struct r_debug' doesn't have
931 the r_ldsomap member. */
933 = read_memory_unsigned_integer (info
->debug_base
+ lmo
->r_version_offset
,
934 lmo
->r_version_size
, byte_order
);
936 CATCH (ex
, RETURN_MASK_ERROR
)
938 exception_print (gdb_stderr
, ex
);
942 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
945 return read_memory_typed_address (info
->debug_base
+ lmo
->r_ldsomap_offset
,
949 /* On Solaris systems with some versions of the dynamic linker,
950 ld.so's l_name pointer points to the SONAME in the string table
951 rather than into writable memory. So that GDB can find shared
952 libraries when loading a core file generated by gcore, ensure that
953 memory areas containing the l_name string are saved in the core
957 svr4_keep_data_in_core (CORE_ADDR vaddr
, unsigned long size
)
959 struct svr4_info
*info
;
961 struct so_list
*newobj
;
962 struct cleanup
*old_chain
;
965 info
= get_svr4_info ();
967 info
->debug_base
= 0;
969 if (!info
->debug_base
)
972 ldsomap
= solib_svr4_r_ldsomap (info
);
976 newobj
= XCNEW (struct so_list
);
977 old_chain
= make_cleanup (xfree
, newobj
);
978 lm_info_svr4
*li
= lm_info_read (ldsomap
);
979 newobj
->lm_info
= li
;
980 make_cleanup (xfree
, newobj
->lm_info
);
981 name_lm
= li
!= NULL
? li
->l_name
: 0;
982 do_cleanups (old_chain
);
984 return (name_lm
>= vaddr
&& name_lm
< vaddr
+ size
);
987 /* Implement the "open_symbol_file_object" target_so_ops method.
989 If no open symbol file, attempt to locate and open the main symbol
990 file. On SVR4 systems, this is the first link map entry. If its
991 name is here, we can open it. Useful when attaching to a process
992 without first loading its symbol file. */
995 open_symbol_file_object (void *from_ttyp
)
997 CORE_ADDR lm
, l_name
;
1000 int from_tty
= *(int *)from_ttyp
;
1001 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
1002 struct type
*ptr_type
= builtin_type (target_gdbarch ())->builtin_data_ptr
;
1003 int l_name_size
= TYPE_LENGTH (ptr_type
);
1004 gdb_byte
*l_name_buf
= (gdb_byte
*) xmalloc (l_name_size
);
1005 struct cleanup
*cleanups
= make_cleanup (xfree
, l_name_buf
);
1006 struct svr4_info
*info
= get_svr4_info ();
1007 symfile_add_flags add_flags
= 0;
1010 add_flags
|= SYMFILE_VERBOSE
;
1012 if (symfile_objfile
)
1013 if (!query (_("Attempt to reload symbols from process? ")))
1015 do_cleanups (cleanups
);
1019 /* Always locate the debug struct, in case it has moved. */
1020 info
->debug_base
= 0;
1021 if (locate_base (info
) == 0)
1023 do_cleanups (cleanups
);
1024 return 0; /* failed somehow... */
1027 /* First link map member should be the executable. */
1028 lm
= solib_svr4_r_map (info
);
1031 do_cleanups (cleanups
);
1032 return 0; /* failed somehow... */
1035 /* Read address of name from target memory to GDB. */
1036 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
1038 /* Convert the address to host format. */
1039 l_name
= extract_typed_address (l_name_buf
, ptr_type
);
1043 do_cleanups (cleanups
);
1044 return 0; /* No filename. */
1047 /* Now fetch the filename from target memory. */
1048 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
1049 make_cleanup (xfree
, filename
);
1053 warning (_("failed to read exec filename from attached file: %s"),
1054 safe_strerror (errcode
));
1055 do_cleanups (cleanups
);
1059 /* Have a pathname: read the symbol file. */
1060 symbol_file_add_main (filename
, add_flags
);
1062 do_cleanups (cleanups
);
1066 /* Data exchange structure for the XML parser as returned by
1067 svr4_current_sos_via_xfer_libraries. */
1069 struct svr4_library_list
1071 struct so_list
*head
, **tailp
;
1073 /* Inferior address of struct link_map used for the main executable. It is
1074 NULL if not known. */
1078 /* Implementation for target_so_ops.free_so. */
1081 svr4_free_so (struct so_list
*so
)
1083 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1088 /* Implement target_so_ops.clear_so. */
1091 svr4_clear_so (struct so_list
*so
)
1093 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1099 /* Free so_list built so far (called via cleanup). */
1102 svr4_free_library_list (void *p_list
)
1104 struct so_list
*list
= *(struct so_list
**) p_list
;
1106 while (list
!= NULL
)
1108 struct so_list
*next
= list
->next
;
1115 /* Copy library list. */
1117 static struct so_list
*
1118 svr4_copy_library_list (struct so_list
*src
)
1120 struct so_list
*dst
= NULL
;
1121 struct so_list
**link
= &dst
;
1125 struct so_list
*newobj
;
1127 newobj
= XNEW (struct so_list
);
1128 memcpy (newobj
, src
, sizeof (struct so_list
));
1130 lm_info_svr4
*src_li
= (lm_info_svr4
*) src
->lm_info
;
1131 newobj
->lm_info
= new lm_info_svr4 (*src_li
);
1133 newobj
->next
= NULL
;
1135 link
= &newobj
->next
;
1143 #ifdef HAVE_LIBEXPAT
1145 #include "xml-support.h"
1147 /* Handle the start of a <library> element. Note: new elements are added
1148 at the tail of the list, keeping the list in order. */
1151 library_list_start_library (struct gdb_xml_parser
*parser
,
1152 const struct gdb_xml_element
*element
,
1153 void *user_data
, VEC(gdb_xml_value_s
) *attributes
)
1155 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1157 = (const char *) xml_find_attribute (attributes
, "name")->value
;
1159 = (ULONGEST
*) xml_find_attribute (attributes
, "lm")->value
;
1161 = (ULONGEST
*) xml_find_attribute (attributes
, "l_addr")->value
;
1163 = (ULONGEST
*) xml_find_attribute (attributes
, "l_ld")->value
;
1164 struct so_list
*new_elem
;
1166 new_elem
= XCNEW (struct so_list
);
1167 lm_info_svr4
*li
= new lm_info_svr4
;
1168 new_elem
->lm_info
= li
;
1170 li
->l_addr_inferior
= *l_addrp
;
1173 strncpy (new_elem
->so_name
, name
, sizeof (new_elem
->so_name
) - 1);
1174 new_elem
->so_name
[sizeof (new_elem
->so_name
) - 1] = 0;
1175 strcpy (new_elem
->so_original_name
, new_elem
->so_name
);
1177 *list
->tailp
= new_elem
;
1178 list
->tailp
= &new_elem
->next
;
1181 /* Handle the start of a <library-list-svr4> element. */
1184 svr4_library_list_start_list (struct gdb_xml_parser
*parser
,
1185 const struct gdb_xml_element
*element
,
1186 void *user_data
, VEC(gdb_xml_value_s
) *attributes
)
1188 struct svr4_library_list
*list
= (struct svr4_library_list
*) user_data
;
1190 = (const char *) xml_find_attribute (attributes
, "version")->value
;
1191 struct gdb_xml_value
*main_lm
= xml_find_attribute (attributes
, "main-lm");
1193 if (strcmp (version
, "1.0") != 0)
1194 gdb_xml_error (parser
,
1195 _("SVR4 Library list has unsupported version \"%s\""),
1199 list
->main_lm
= *(ULONGEST
*) main_lm
->value
;
1202 /* The allowed elements and attributes for an XML library list.
1203 The root element is a <library-list>. */
1205 static const struct gdb_xml_attribute svr4_library_attributes
[] =
1207 { "name", GDB_XML_AF_NONE
, NULL
, NULL
},
1208 { "lm", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1209 { "l_addr", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1210 { "l_ld", GDB_XML_AF_NONE
, gdb_xml_parse_attr_ulongest
, NULL
},
1211 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1214 static const struct gdb_xml_element svr4_library_list_children
[] =
1217 "library", svr4_library_attributes
, NULL
,
1218 GDB_XML_EF_REPEATABLE
| GDB_XML_EF_OPTIONAL
,
1219 library_list_start_library
, NULL
1221 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1224 static const struct gdb_xml_attribute svr4_library_list_attributes
[] =
1226 { "version", GDB_XML_AF_NONE
, NULL
, NULL
},
1227 { "main-lm", GDB_XML_AF_OPTIONAL
, gdb_xml_parse_attr_ulongest
, NULL
},
1228 { NULL
, GDB_XML_AF_NONE
, NULL
, NULL
}
1231 static const struct gdb_xml_element svr4_library_list_elements
[] =
1233 { "library-list-svr4", svr4_library_list_attributes
, svr4_library_list_children
,
1234 GDB_XML_EF_NONE
, svr4_library_list_start_list
, NULL
},
1235 { NULL
, NULL
, NULL
, GDB_XML_EF_NONE
, NULL
, NULL
}
1238 /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if
1240 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1241 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1242 empty, caller is responsible for freeing all its entries. */
1245 svr4_parse_libraries (const char *document
, struct svr4_library_list
*list
)
1247 struct cleanup
*back_to
= make_cleanup (svr4_free_library_list
,
1250 memset (list
, 0, sizeof (*list
));
1251 list
->tailp
= &list
->head
;
1252 if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd",
1253 svr4_library_list_elements
, document
, list
) == 0)
1255 /* Parsed successfully, keep the result. */
1256 discard_cleanups (back_to
);
1260 do_cleanups (back_to
);
1264 /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet.
1266 Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such
1267 case. Return 1 if *SO_LIST_RETURN contains the library list, it may be
1268 empty, caller is responsible for freeing all its entries.
1270 Note that ANNEX must be NULL if the remote does not explicitly allow
1271 qXfer:libraries-svr4:read packets with non-empty annexes. Support for
1272 this can be checked using target_augmented_libraries_svr4_read (). */
1275 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1278 char *svr4_library_document
;
1280 struct cleanup
*back_to
;
1282 gdb_assert (annex
== NULL
|| target_augmented_libraries_svr4_read ());
1284 /* Fetch the list of shared libraries. */
1285 svr4_library_document
= target_read_stralloc (¤t_target
,
1286 TARGET_OBJECT_LIBRARIES_SVR4
,
1288 if (svr4_library_document
== NULL
)
1291 back_to
= make_cleanup (xfree
, svr4_library_document
);
1292 result
= svr4_parse_libraries (svr4_library_document
, list
);
1293 do_cleanups (back_to
);
1301 svr4_current_sos_via_xfer_libraries (struct svr4_library_list
*list
,
1309 /* If no shared library information is available from the dynamic
1310 linker, build a fallback list from other sources. */
1312 static struct so_list
*
1313 svr4_default_sos (void)
1315 struct svr4_info
*info
= get_svr4_info ();
1316 struct so_list
*newobj
;
1318 if (!info
->debug_loader_offset_p
)
1321 newobj
= XCNEW (struct so_list
);
1322 lm_info_svr4
*li
= new lm_info_svr4
;
1323 newobj
->lm_info
= li
;
1325 /* Nothing will ever check the other fields if we set l_addr_p. */
1326 li
->l_addr
= info
->debug_loader_offset
;
1329 strncpy (newobj
->so_name
, info
->debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
1330 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1331 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1336 /* Read the whole inferior libraries chain starting at address LM.
1337 Expect the first entry in the chain's previous entry to be PREV_LM.
1338 Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the
1339 first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according
1340 to it. Returns nonzero upon success. If zero is returned the
1341 entries stored to LINK_PTR_PTR are still valid although they may
1342 represent only part of the inferior library list. */
1345 svr4_read_so_list (CORE_ADDR lm
, CORE_ADDR prev_lm
,
1346 struct so_list
***link_ptr_ptr
, int ignore_first
)
1348 CORE_ADDR first_l_name
= 0;
1351 for (; lm
!= 0; prev_lm
= lm
, lm
= next_lm
)
1356 so_list_up
newobj (XCNEW (struct so_list
));
1358 lm_info_svr4
*li
= lm_info_read (lm
);
1359 newobj
->lm_info
= li
;
1363 next_lm
= li
->l_next
;
1365 if (li
->l_prev
!= prev_lm
)
1367 warning (_("Corrupted shared library list: %s != %s"),
1368 paddress (target_gdbarch (), prev_lm
),
1369 paddress (target_gdbarch (), li
->l_prev
));
1373 /* For SVR4 versions, the first entry in the link map is for the
1374 inferior executable, so we must ignore it. For some versions of
1375 SVR4, it has no name. For others (Solaris 2.3 for example), it
1376 does have a name, so we can no longer use a missing name to
1377 decide when to ignore it. */
1378 if (ignore_first
&& li
->l_prev
== 0)
1380 struct svr4_info
*info
= get_svr4_info ();
1382 first_l_name
= li
->l_name
;
1383 info
->main_lm_addr
= li
->lm_addr
;
1387 /* Extract this shared object's name. */
1388 target_read_string (li
->l_name
, &buffer
, SO_NAME_MAX_PATH_SIZE
- 1,
1392 /* If this entry's l_name address matches that of the
1393 inferior executable, then this is not a normal shared
1394 object, but (most likely) a vDSO. In this case, silently
1395 skip it; otherwise emit a warning. */
1396 if (first_l_name
== 0 || li
->l_name
!= first_l_name
)
1397 warning (_("Can't read pathname for load map: %s."),
1398 safe_strerror (errcode
));
1402 strncpy (newobj
->so_name
, buffer
, SO_NAME_MAX_PATH_SIZE
- 1);
1403 newobj
->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
1404 strcpy (newobj
->so_original_name
, newobj
->so_name
);
1407 /* If this entry has no name, or its name matches the name
1408 for the main executable, don't include it in the list. */
1409 if (! newobj
->so_name
[0] || match_main (newobj
->so_name
))
1413 /* Don't free it now. */
1414 **link_ptr_ptr
= newobj
.release ();
1415 *link_ptr_ptr
= &(**link_ptr_ptr
)->next
;
1421 /* Read the full list of currently loaded shared objects directly
1422 from the inferior, without referring to any libraries read and
1423 stored by the probes interface. Handle special cases relating
1424 to the first elements of the list. */
1426 static struct so_list
*
1427 svr4_current_sos_direct (struct svr4_info
*info
)
1430 struct so_list
*head
= NULL
;
1431 struct so_list
**link_ptr
= &head
;
1432 struct cleanup
*back_to
;
1434 struct svr4_library_list library_list
;
1436 /* Fall back to manual examination of the target if the packet is not
1437 supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp
1438 tests a case where gdbserver cannot find the shared libraries list while
1439 GDB itself is able to find it via SYMFILE_OBJFILE.
1441 Unfortunately statically linked inferiors will also fall back through this
1442 suboptimal code path. */
1444 info
->using_xfer
= svr4_current_sos_via_xfer_libraries (&library_list
,
1446 if (info
->using_xfer
)
1448 if (library_list
.main_lm
)
1449 info
->main_lm_addr
= library_list
.main_lm
;
1451 return library_list
.head
? library_list
.head
: svr4_default_sos ();
1454 /* Always locate the debug struct, in case it has moved. */
1455 info
->debug_base
= 0;
1458 /* If we can't find the dynamic linker's base structure, this
1459 must not be a dynamically linked executable. Hmm. */
1460 if (! info
->debug_base
)
1461 return svr4_default_sos ();
1463 /* Assume that everything is a library if the dynamic loader was loaded
1464 late by a static executable. */
1465 if (exec_bfd
&& bfd_get_section_by_name (exec_bfd
, ".dynamic") == NULL
)
1470 back_to
= make_cleanup (svr4_free_library_list
, &head
);
1472 /* Walk the inferior's link map list, and build our list of
1473 `struct so_list' nodes. */
1474 lm
= solib_svr4_r_map (info
);
1476 svr4_read_so_list (lm
, 0, &link_ptr
, ignore_first
);
1478 /* On Solaris, the dynamic linker is not in the normal list of
1479 shared objects, so make sure we pick it up too. Having
1480 symbol information for the dynamic linker is quite crucial
1481 for skipping dynamic linker resolver code. */
1482 lm
= solib_svr4_r_ldsomap (info
);
1484 svr4_read_so_list (lm
, 0, &link_ptr
, 0);
1486 discard_cleanups (back_to
);
1489 return svr4_default_sos ();
1494 /* Implement the main part of the "current_sos" target_so_ops
1497 static struct so_list
*
1498 svr4_current_sos_1 (void)
1500 struct svr4_info
*info
= get_svr4_info ();
1502 /* If the solib list has been read and stored by the probes
1503 interface then we return a copy of the stored list. */
1504 if (info
->solib_list
!= NULL
)
1505 return svr4_copy_library_list (info
->solib_list
);
1507 /* Otherwise obtain the solib list directly from the inferior. */
1508 return svr4_current_sos_direct (info
);
1511 /* Implement the "current_sos" target_so_ops method. */
1513 static struct so_list
*
1514 svr4_current_sos (void)
1516 struct so_list
*so_head
= svr4_current_sos_1 ();
1517 struct mem_range vsyscall_range
;
1519 /* Filter out the vDSO module, if present. Its symbol file would
1520 not be found on disk. The vDSO/vsyscall's OBJFILE is instead
1521 managed by symfile-mem.c:add_vsyscall_page. */
1522 if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range
)
1523 && vsyscall_range
.length
!= 0)
1525 struct so_list
**sop
;
1528 while (*sop
!= NULL
)
1530 struct so_list
*so
= *sop
;
1532 /* We can't simply match the vDSO by starting address alone,
1533 because lm_info->l_addr_inferior (and also l_addr) do not
1534 necessarily represent the real starting address of the
1535 ELF if the vDSO's ELF itself is "prelinked". The l_ld
1536 field (the ".dynamic" section of the shared object)
1537 always points at the absolute/resolved address though.
1538 So check whether that address is inside the vDSO's
1541 E.g., on Linux 3.16 (x86_64) the vDSO is a regular
1542 0-based ELF, and we see:
1545 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000
1546 (gdb) p/x *_r_debug.r_map.l_next
1547 $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...}
1549 And on Linux 2.6.32 (x86_64) we see:
1552 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000
1553 (gdb) p/x *_r_debug.r_map.l_next
1554 $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... }
1556 Dumping that vDSO shows:
1558 (gdb) info proc mappings
1559 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso]
1560 (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000
1561 # readelf -Wa vdso.bin
1563 Entry point address: 0xffffffffff700700
1566 [Nr] Name Type Address Off Size
1567 [ 0] NULL 0000000000000000 000000 000000
1568 [ 1] .hash HASH ffffffffff700120 000120 000038
1569 [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8
1571 [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0
1574 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1576 if (address_in_mem_range (li
->l_ld
, &vsyscall_range
))
1590 /* Get the address of the link_map for a given OBJFILE. */
1593 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
1596 struct svr4_info
*info
= get_svr4_info ();
1598 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1599 if (info
->main_lm_addr
== 0)
1600 solib_add (NULL
, 0, auto_solib_add
);
1602 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1603 if (objfile
== symfile_objfile
)
1604 return info
->main_lm_addr
;
1606 /* The other link map addresses may be found by examining the list
1607 of shared libraries. */
1608 for (so
= master_so_list (); so
; so
= so
->next
)
1609 if (so
->objfile
== objfile
)
1611 lm_info_svr4
*li
= (lm_info_svr4
*) so
->lm_info
;
1620 /* On some systems, the only way to recognize the link map entry for
1621 the main executable file is by looking at its name. Return
1622 non-zero iff SONAME matches one of the known main executable names. */
1625 match_main (const char *soname
)
1627 const char * const *mainp
;
1629 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
1631 if (strcmp (soname
, *mainp
) == 0)
1638 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1639 SVR4 run time loader. */
1642 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
1644 struct svr4_info
*info
= get_svr4_info ();
1646 return ((pc
>= info
->interp_text_sect_low
1647 && pc
< info
->interp_text_sect_high
)
1648 || (pc
>= info
->interp_plt_sect_low
1649 && pc
< info
->interp_plt_sect_high
)
1650 || in_plt_section (pc
)
1651 || in_gnu_ifunc_stub (pc
));
1654 /* Given an executable's ABFD and target, compute the entry-point
1658 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
1662 /* KevinB wrote ... for most targets, the address returned by
1663 bfd_get_start_address() is the entry point for the start
1664 function. But, for some targets, bfd_get_start_address() returns
1665 the address of a function descriptor from which the entry point
1666 address may be extracted. This address is extracted by
1667 gdbarch_convert_from_func_ptr_addr(). The method
1668 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1669 function for targets which don't use function descriptors. */
1670 addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
1671 bfd_get_start_address (abfd
),
1673 return gdbarch_addr_bits_remove (target_gdbarch (), addr
);
1676 /* A probe and its associated action. */
1678 struct probe_and_action
1681 struct probe
*probe
;
1683 /* The relocated address of the probe. */
1687 enum probe_action action
;
1690 /* Returns a hash code for the probe_and_action referenced by p. */
1693 hash_probe_and_action (const void *p
)
1695 const struct probe_and_action
*pa
= (const struct probe_and_action
*) p
;
1697 return (hashval_t
) pa
->address
;
1700 /* Returns non-zero if the probe_and_actions referenced by p1 and p2
1704 equal_probe_and_action (const void *p1
, const void *p2
)
1706 const struct probe_and_action
*pa1
= (const struct probe_and_action
*) p1
;
1707 const struct probe_and_action
*pa2
= (const struct probe_and_action
*) p2
;
1709 return pa1
->address
== pa2
->address
;
1712 /* Register a solib event probe and its associated action in the
1716 register_solib_event_probe (struct probe
*probe
, CORE_ADDR address
,
1717 enum probe_action action
)
1719 struct svr4_info
*info
= get_svr4_info ();
1720 struct probe_and_action lookup
, *pa
;
1723 /* Create the probes table, if necessary. */
1724 if (info
->probes_table
== NULL
)
1725 info
->probes_table
= htab_create_alloc (1, hash_probe_and_action
,
1726 equal_probe_and_action
,
1727 xfree
, xcalloc
, xfree
);
1729 lookup
.probe
= probe
;
1730 lookup
.address
= address
;
1731 slot
= htab_find_slot (info
->probes_table
, &lookup
, INSERT
);
1732 gdb_assert (*slot
== HTAB_EMPTY_ENTRY
);
1734 pa
= XCNEW (struct probe_and_action
);
1736 pa
->address
= address
;
1737 pa
->action
= action
;
1742 /* Get the solib event probe at the specified location, and the
1743 action associated with it. Returns NULL if no solib event probe
1746 static struct probe_and_action
*
1747 solib_event_probe_at (struct svr4_info
*info
, CORE_ADDR address
)
1749 struct probe_and_action lookup
;
1752 lookup
.address
= address
;
1753 slot
= htab_find_slot (info
->probes_table
, &lookup
, NO_INSERT
);
1758 return (struct probe_and_action
*) *slot
;
1761 /* Decide what action to take when the specified solib event probe is
1764 static enum probe_action
1765 solib_event_probe_action (struct probe_and_action
*pa
)
1767 enum probe_action action
;
1768 unsigned probe_argc
= 0;
1769 struct frame_info
*frame
= get_current_frame ();
1771 action
= pa
->action
;
1772 if (action
== DO_NOTHING
|| action
== PROBES_INTERFACE_FAILED
)
1775 gdb_assert (action
== FULL_RELOAD
|| action
== UPDATE_OR_RELOAD
);
1777 /* Check that an appropriate number of arguments has been supplied.
1779 arg0: Lmid_t lmid (mandatory)
1780 arg1: struct r_debug *debug_base (mandatory)
1781 arg2: struct link_map *new (optional, for incremental updates) */
1784 probe_argc
= get_probe_argument_count (pa
->probe
, frame
);
1786 CATCH (ex
, RETURN_MASK_ERROR
)
1788 exception_print (gdb_stderr
, ex
);
1793 /* If get_probe_argument_count throws an exception, probe_argc will
1794 be set to zero. However, if pa->probe does not have arguments,
1795 then get_probe_argument_count will succeed but probe_argc will
1796 also be zero. Both cases happen because of different things, but
1797 they are treated equally here: action will be set to
1798 PROBES_INTERFACE_FAILED. */
1799 if (probe_argc
== 2)
1800 action
= FULL_RELOAD
;
1801 else if (probe_argc
< 2)
1802 action
= PROBES_INTERFACE_FAILED
;
1807 /* Populate the shared object list by reading the entire list of
1808 shared objects from the inferior. Handle special cases relating
1809 to the first elements of the list. Returns nonzero on success. */
1812 solist_update_full (struct svr4_info
*info
)
1814 free_solib_list (info
);
1815 info
->solib_list
= svr4_current_sos_direct (info
);
1820 /* Update the shared object list starting from the link-map entry
1821 passed by the linker in the probe's third argument. Returns
1822 nonzero if the list was successfully updated, or zero to indicate
1826 solist_update_incremental (struct svr4_info
*info
, CORE_ADDR lm
)
1828 struct so_list
*tail
;
1831 /* svr4_current_sos_direct contains logic to handle a number of
1832 special cases relating to the first elements of the list. To
1833 avoid duplicating this logic we defer to solist_update_full
1834 if the list is empty. */
1835 if (info
->solib_list
== NULL
)
1838 /* Fall back to a full update if we are using a remote target
1839 that does not support incremental transfers. */
1840 if (info
->using_xfer
&& !target_augmented_libraries_svr4_read ())
1843 /* Walk to the end of the list. */
1844 for (tail
= info
->solib_list
; tail
->next
!= NULL
; tail
= tail
->next
)
1847 lm_info_svr4
*li
= (lm_info_svr4
*) tail
->lm_info
;
1848 prev_lm
= li
->lm_addr
;
1850 /* Read the new objects. */
1851 if (info
->using_xfer
)
1853 struct svr4_library_list library_list
;
1856 xsnprintf (annex
, sizeof (annex
), "start=%s;prev=%s",
1857 phex_nz (lm
, sizeof (lm
)),
1858 phex_nz (prev_lm
, sizeof (prev_lm
)));
1859 if (!svr4_current_sos_via_xfer_libraries (&library_list
, annex
))
1862 tail
->next
= library_list
.head
;
1866 struct so_list
**link
= &tail
->next
;
1868 /* IGNORE_FIRST may safely be set to zero here because the
1869 above check and deferral to solist_update_full ensures
1870 that this call to svr4_read_so_list will never see the
1872 if (!svr4_read_so_list (lm
, prev_lm
, &link
, 0))
1879 /* Disable the probes-based linker interface and revert to the
1880 original interface. We don't reset the breakpoints as the
1881 ones set up for the probes-based interface are adequate. */
1884 disable_probes_interface_cleanup (void *arg
)
1886 struct svr4_info
*info
= get_svr4_info ();
1888 warning (_("Probes-based dynamic linker interface failed.\n"
1889 "Reverting to original interface.\n"));
1891 free_probes_table (info
);
1892 free_solib_list (info
);
1895 /* Update the solib list as appropriate when using the
1896 probes-based linker interface. Do nothing if using the
1897 standard interface. */
1900 svr4_handle_solib_event (void)
1902 struct svr4_info
*info
= get_svr4_info ();
1903 struct probe_and_action
*pa
;
1904 enum probe_action action
;
1905 struct cleanup
*old_chain
, *usm_chain
;
1906 struct value
*val
= NULL
;
1907 CORE_ADDR pc
, debug_base
, lm
= 0;
1908 struct frame_info
*frame
= get_current_frame ();
1910 /* Do nothing if not using the probes interface. */
1911 if (info
->probes_table
== NULL
)
1914 /* If anything goes wrong we revert to the original linker
1916 old_chain
= make_cleanup (disable_probes_interface_cleanup
, NULL
);
1918 pc
= regcache_read_pc (get_current_regcache ());
1919 pa
= solib_event_probe_at (info
, pc
);
1922 do_cleanups (old_chain
);
1926 action
= solib_event_probe_action (pa
);
1927 if (action
== PROBES_INTERFACE_FAILED
)
1929 do_cleanups (old_chain
);
1933 if (action
== DO_NOTHING
)
1935 discard_cleanups (old_chain
);
1939 /* evaluate_probe_argument looks up symbols in the dynamic linker
1940 using find_pc_section. find_pc_section is accelerated by a cache
1941 called the section map. The section map is invalidated every
1942 time a shared library is loaded or unloaded, and if the inferior
1943 is generating a lot of shared library events then the section map
1944 will be updated every time svr4_handle_solib_event is called.
1945 We called find_pc_section in svr4_create_solib_event_breakpoints,
1946 so we can guarantee that the dynamic linker's sections are in the
1947 section map. We can therefore inhibit section map updates across
1948 these calls to evaluate_probe_argument and save a lot of time. */
1949 inhibit_section_map_updates (current_program_space
);
1950 usm_chain
= make_cleanup (resume_section_map_updates_cleanup
,
1951 current_program_space
);
1955 val
= evaluate_probe_argument (pa
->probe
, 1, frame
);
1957 CATCH (ex
, RETURN_MASK_ERROR
)
1959 exception_print (gdb_stderr
, ex
);
1966 do_cleanups (old_chain
);
1970 debug_base
= value_as_address (val
);
1971 if (debug_base
== 0)
1973 do_cleanups (old_chain
);
1977 /* Always locate the debug struct, in case it moved. */
1978 info
->debug_base
= 0;
1979 if (locate_base (info
) == 0)
1981 do_cleanups (old_chain
);
1985 /* GDB does not currently support libraries loaded via dlmopen
1986 into namespaces other than the initial one. We must ignore
1987 any namespace other than the initial namespace here until
1988 support for this is added to GDB. */
1989 if (debug_base
!= info
->debug_base
)
1990 action
= DO_NOTHING
;
1992 if (action
== UPDATE_OR_RELOAD
)
1996 val
= evaluate_probe_argument (pa
->probe
, 2, frame
);
1998 CATCH (ex
, RETURN_MASK_ERROR
)
2000 exception_print (gdb_stderr
, ex
);
2001 do_cleanups (old_chain
);
2007 lm
= value_as_address (val
);
2010 action
= FULL_RELOAD
;
2013 /* Resume section map updates. */
2014 do_cleanups (usm_chain
);
2016 if (action
== UPDATE_OR_RELOAD
)
2018 if (!solist_update_incremental (info
, lm
))
2019 action
= FULL_RELOAD
;
2022 if (action
== FULL_RELOAD
)
2024 if (!solist_update_full (info
))
2026 do_cleanups (old_chain
);
2031 discard_cleanups (old_chain
);
2034 /* Helper function for svr4_update_solib_event_breakpoints. */
2037 svr4_update_solib_event_breakpoint (struct breakpoint
*b
, void *arg
)
2039 struct bp_location
*loc
;
2041 if (b
->type
!= bp_shlib_event
)
2043 /* Continue iterating. */
2047 for (loc
= b
->loc
; loc
!= NULL
; loc
= loc
->next
)
2049 struct svr4_info
*info
;
2050 struct probe_and_action
*pa
;
2052 info
= ((struct svr4_info
*)
2053 program_space_data (loc
->pspace
, solib_svr4_pspace_data
));
2054 if (info
== NULL
|| info
->probes_table
== NULL
)
2057 pa
= solib_event_probe_at (info
, loc
->address
);
2061 if (pa
->action
== DO_NOTHING
)
2063 if (b
->enable_state
== bp_disabled
&& stop_on_solib_events
)
2064 enable_breakpoint (b
);
2065 else if (b
->enable_state
== bp_enabled
&& !stop_on_solib_events
)
2066 disable_breakpoint (b
);
2072 /* Continue iterating. */
2076 /* Enable or disable optional solib event breakpoints as appropriate.
2077 Called whenever stop_on_solib_events is changed. */
2080 svr4_update_solib_event_breakpoints (void)
2082 iterate_over_breakpoints (svr4_update_solib_event_breakpoint
, NULL
);
2085 /* Create and register solib event breakpoints. PROBES is an array
2086 of NUM_PROBES elements, each of which is vector of probes. A
2087 solib event breakpoint will be created and registered for each
2091 svr4_create_probe_breakpoints (struct gdbarch
*gdbarch
,
2092 VEC (probe_p
) **probes
,
2093 struct objfile
*objfile
)
2097 for (i
= 0; i
< NUM_PROBES
; i
++)
2099 enum probe_action action
= probe_info
[i
].action
;
2100 struct probe
*probe
;
2104 VEC_iterate (probe_p
, probes
[i
], ix
, probe
);
2107 CORE_ADDR address
= get_probe_address (probe
, objfile
);
2109 create_solib_event_breakpoint (gdbarch
, address
);
2110 register_solib_event_probe (probe
, address
, action
);
2114 svr4_update_solib_event_breakpoints ();
2117 /* Both the SunOS and the SVR4 dynamic linkers call a marker function
2118 before and after mapping and unmapping shared libraries. The sole
2119 purpose of this method is to allow debuggers to set a breakpoint so
2120 they can track these changes.
2122 Some versions of the glibc dynamic linker contain named probes
2123 to allow more fine grained stopping. Given the address of the
2124 original marker function, this function attempts to find these
2125 probes, and if found, sets breakpoints on those instead. If the
2126 probes aren't found, a single breakpoint is set on the original
2130 svr4_create_solib_event_breakpoints (struct gdbarch
*gdbarch
,
2133 struct obj_section
*os
;
2135 os
= find_pc_section (address
);
2140 for (with_prefix
= 0; with_prefix
<= 1; with_prefix
++)
2142 VEC (probe_p
) *probes
[NUM_PROBES
];
2143 int all_probes_found
= 1;
2144 int checked_can_use_probe_arguments
= 0;
2147 memset (probes
, 0, sizeof (probes
));
2148 for (i
= 0; i
< NUM_PROBES
; i
++)
2150 const char *name
= probe_info
[i
].name
;
2154 /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4
2155 shipped with an early version of the probes code in
2156 which the probes' names were prefixed with "rtld_"
2157 and the "map_failed" probe did not exist. The
2158 locations of the probes are otherwise the same, so
2159 we check for probes with prefixed names if probes
2160 with unprefixed names are not present. */
2163 xsnprintf (buf
, sizeof (buf
), "rtld_%s", name
);
2167 probes
[i
] = find_probes_in_objfile (os
->objfile
, "rtld", name
);
2169 /* The "map_failed" probe did not exist in early
2170 versions of the probes code in which the probes'
2171 names were prefixed with "rtld_". */
2172 if (strcmp (name
, "rtld_map_failed") == 0)
2175 if (VEC_empty (probe_p
, probes
[i
]))
2177 all_probes_found
= 0;
2181 /* Ensure probe arguments can be evaluated. */
2182 if (!checked_can_use_probe_arguments
)
2184 p
= VEC_index (probe_p
, probes
[i
], 0);
2185 if (!can_evaluate_probe_arguments (p
))
2187 all_probes_found
= 0;
2190 checked_can_use_probe_arguments
= 1;
2194 if (all_probes_found
)
2195 svr4_create_probe_breakpoints (gdbarch
, probes
, os
->objfile
);
2197 for (i
= 0; i
< NUM_PROBES
; i
++)
2198 VEC_free (probe_p
, probes
[i
]);
2200 if (all_probes_found
)
2205 create_solib_event_breakpoint (gdbarch
, address
);
2208 /* Helper function for gdb_bfd_lookup_symbol. */
2211 cmp_name_and_sec_flags (const asymbol
*sym
, const void *data
)
2213 return (strcmp (sym
->name
, (const char *) data
) == 0
2214 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0);
2216 /* Arrange for dynamic linker to hit breakpoint.
2218 Both the SunOS and the SVR4 dynamic linkers have, as part of their
2219 debugger interface, support for arranging for the inferior to hit
2220 a breakpoint after mapping in the shared libraries. This function
2221 enables that breakpoint.
2223 For SunOS, there is a special flag location (in_debugger) which we
2224 set to 1. When the dynamic linker sees this flag set, it will set
2225 a breakpoint at a location known only to itself, after saving the
2226 original contents of that place and the breakpoint address itself,
2227 in it's own internal structures. When we resume the inferior, it
2228 will eventually take a SIGTRAP when it runs into the breakpoint.
2229 We handle this (in a different place) by restoring the contents of
2230 the breakpointed location (which is only known after it stops),
2231 chasing around to locate the shared libraries that have been
2232 loaded, then resuming.
2234 For SVR4, the debugger interface structure contains a member (r_brk)
2235 which is statically initialized at the time the shared library is
2236 built, to the offset of a function (_r_debug_state) which is guaran-
2237 teed to be called once before mapping in a library, and again when
2238 the mapping is complete. At the time we are examining this member,
2239 it contains only the unrelocated offset of the function, so we have
2240 to do our own relocation. Later, when the dynamic linker actually
2241 runs, it relocates r_brk to be the actual address of _r_debug_state().
2243 The debugger interface structure also contains an enumeration which
2244 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
2245 depending upon whether or not the library is being mapped or unmapped,
2246 and then set to RT_CONSISTENT after the library is mapped/unmapped. */
2249 enable_break (struct svr4_info
*info
, int from_tty
)
2251 struct bound_minimal_symbol msymbol
;
2252 const char * const *bkpt_namep
;
2253 asection
*interp_sect
;
2257 info
->interp_text_sect_low
= info
->interp_text_sect_high
= 0;
2258 info
->interp_plt_sect_low
= info
->interp_plt_sect_high
= 0;
2260 /* If we already have a shared library list in the target, and
2261 r_debug contains r_brk, set the breakpoint there - this should
2262 mean r_brk has already been relocated. Assume the dynamic linker
2263 is the object containing r_brk. */
2265 solib_add (NULL
, from_tty
, auto_solib_add
);
2267 if (info
->debug_base
&& solib_svr4_r_map (info
) != 0)
2268 sym_addr
= solib_svr4_r_brk (info
);
2272 struct obj_section
*os
;
2274 sym_addr
= gdbarch_addr_bits_remove
2275 (target_gdbarch (), gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2279 /* On at least some versions of Solaris there's a dynamic relocation
2280 on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
2281 we get control before the dynamic linker has self-relocated.
2282 Check if SYM_ADDR is in a known section, if it is assume we can
2283 trust its value. This is just a heuristic though, it could go away
2284 or be replaced if it's getting in the way.
2286 On ARM we need to know whether the ISA of rtld_db_dlactivity (or
2287 however it's spelled in your particular system) is ARM or Thumb.
2288 That knowledge is encoded in the address, if it's Thumb the low bit
2289 is 1. However, we've stripped that info above and it's not clear
2290 what all the consequences are of passing a non-addr_bits_remove'd
2291 address to svr4_create_solib_event_breakpoints. The call to
2292 find_pc_section verifies we know about the address and have some
2293 hope of computing the right kind of breakpoint to use (via
2294 symbol info). It does mean that GDB needs to be pointed at a
2295 non-stripped version of the dynamic linker in order to obtain
2296 information it already knows about. Sigh. */
2298 os
= find_pc_section (sym_addr
);
2301 /* Record the relocated start and end address of the dynamic linker
2302 text and plt section for svr4_in_dynsym_resolve_code. */
2304 CORE_ADDR load_addr
;
2306 tmp_bfd
= os
->objfile
->obfd
;
2307 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
2308 SECT_OFF_TEXT (os
->objfile
));
2310 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
2313 info
->interp_text_sect_low
=
2314 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
2315 info
->interp_text_sect_high
=
2316 info
->interp_text_sect_low
2317 + bfd_section_size (tmp_bfd
, interp_sect
);
2319 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
2322 info
->interp_plt_sect_low
=
2323 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
2324 info
->interp_plt_sect_high
=
2325 info
->interp_plt_sect_low
2326 + bfd_section_size (tmp_bfd
, interp_sect
);
2329 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2334 /* Find the program interpreter; if not found, warn the user and drop
2335 into the old breakpoint at symbol code. */
2336 interp_name
= find_program_interpreter ();
2339 CORE_ADDR load_addr
= 0;
2340 int load_addr_found
= 0;
2341 int loader_found_in_list
= 0;
2343 struct target_ops
*tmp_bfd_target
;
2347 /* Now we need to figure out where the dynamic linker was
2348 loaded so that we can load its symbols and place a breakpoint
2349 in the dynamic linker itself.
2351 This address is stored on the stack. However, I've been unable
2352 to find any magic formula to find it for Solaris (appears to
2353 be trivial on GNU/Linux). Therefore, we have to try an alternate
2354 mechanism to find the dynamic linker's base address. */
2356 gdb_bfd_ref_ptr tmp_bfd
;
2359 tmp_bfd
= solib_bfd_open (interp_name
);
2361 CATCH (ex
, RETURN_MASK_ALL
)
2366 if (tmp_bfd
== NULL
)
2367 goto bkpt_at_symbol
;
2369 /* Now convert the TMP_BFD into a target. That way target, as
2370 well as BFD operations can be used. target_bfd_reopen
2371 acquires its own reference. */
2372 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
.get ());
2374 /* On a running target, we can get the dynamic linker's base
2375 address from the shared library table. */
2376 so
= master_so_list ();
2379 if (svr4_same_1 (interp_name
, so
->so_original_name
))
2381 load_addr_found
= 1;
2382 loader_found_in_list
= 1;
2383 load_addr
= lm_addr_check (so
, tmp_bfd
.get ());
2389 /* If we were not able to find the base address of the loader
2390 from our so_list, then try using the AT_BASE auxilliary entry. */
2391 if (!load_addr_found
)
2392 if (target_auxv_search (¤t_target
, AT_BASE
, &load_addr
) > 0)
2394 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
2396 /* Ensure LOAD_ADDR has proper sign in its possible upper bits so
2397 that `+ load_addr' will overflow CORE_ADDR width not creating
2398 invalid addresses like 0x101234567 for 32bit inferiors on 64bit
2401 if (addr_bit
< (sizeof (CORE_ADDR
) * HOST_CHAR_BIT
))
2403 CORE_ADDR space_size
= (CORE_ADDR
) 1 << addr_bit
;
2404 CORE_ADDR tmp_entry_point
= exec_entry_point (tmp_bfd
.get (),
2407 gdb_assert (load_addr
< space_size
);
2409 /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked
2410 64bit ld.so with 32bit executable, it should not happen. */
2412 if (tmp_entry_point
< space_size
2413 && tmp_entry_point
+ load_addr
>= space_size
)
2414 load_addr
-= space_size
;
2417 load_addr_found
= 1;
2420 /* Otherwise we find the dynamic linker's base address by examining
2421 the current pc (which should point at the entry point for the
2422 dynamic linker) and subtracting the offset of the entry point.
2424 This is more fragile than the previous approaches, but is a good
2425 fallback method because it has actually been working well in
2427 if (!load_addr_found
)
2429 struct regcache
*regcache
2430 = get_thread_arch_regcache (inferior_ptid
, target_gdbarch ());
2432 load_addr
= (regcache_read_pc (regcache
)
2433 - exec_entry_point (tmp_bfd
.get (), tmp_bfd_target
));
2436 if (!loader_found_in_list
)
2438 info
->debug_loader_name
= xstrdup (interp_name
);
2439 info
->debug_loader_offset_p
= 1;
2440 info
->debug_loader_offset
= load_addr
;
2441 solib_add (NULL
, from_tty
, auto_solib_add
);
2444 /* Record the relocated start and end address of the dynamic linker
2445 text and plt section for svr4_in_dynsym_resolve_code. */
2446 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".text");
2449 info
->interp_text_sect_low
=
2450 bfd_section_vma (tmp_bfd
.get (), interp_sect
) + load_addr
;
2451 info
->interp_text_sect_high
=
2452 info
->interp_text_sect_low
2453 + bfd_section_size (tmp_bfd
.get (), interp_sect
);
2455 interp_sect
= bfd_get_section_by_name (tmp_bfd
.get (), ".plt");
2458 info
->interp_plt_sect_low
=
2459 bfd_section_vma (tmp_bfd
.get (), interp_sect
) + load_addr
;
2460 info
->interp_plt_sect_high
=
2461 info
->interp_plt_sect_low
2462 + bfd_section_size (tmp_bfd
.get (), interp_sect
);
2465 /* Now try to set a breakpoint in the dynamic linker. */
2466 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2468 sym_addr
= gdb_bfd_lookup_symbol (tmp_bfd
.get (),
2469 cmp_name_and_sec_flags
,
2476 /* Convert 'sym_addr' from a function pointer to an address.
2477 Because we pass tmp_bfd_target instead of the current
2478 target, this will always produce an unrelocated value. */
2479 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2483 /* We're done with both the temporary bfd and target. Closing
2484 the target closes the underlying bfd, because it holds the
2485 only remaining reference. */
2486 target_close (tmp_bfd_target
);
2490 svr4_create_solib_event_breakpoints (target_gdbarch (),
2491 load_addr
+ sym_addr
);
2492 xfree (interp_name
);
2496 /* For whatever reason we couldn't set a breakpoint in the dynamic
2497 linker. Warn and drop into the old code. */
2499 xfree (interp_name
);
2500 warning (_("Unable to find dynamic linker breakpoint function.\n"
2501 "GDB will be unable to debug shared library initializers\n"
2502 "and track explicitly loaded dynamic code."));
2505 /* Scan through the lists of symbols, trying to look up the symbol and
2506 set a breakpoint there. Terminate loop when we/if we succeed. */
2508 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2510 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
2511 if ((msymbol
.minsym
!= NULL
)
2512 && (BMSYMBOL_VALUE_ADDRESS (msymbol
) != 0))
2514 sym_addr
= BMSYMBOL_VALUE_ADDRESS (msymbol
);
2515 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2518 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2523 if (interp_name
!= NULL
&& !current_inferior ()->attach_flag
)
2525 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
2527 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
2528 if ((msymbol
.minsym
!= NULL
)
2529 && (BMSYMBOL_VALUE_ADDRESS (msymbol
) != 0))
2531 sym_addr
= BMSYMBOL_VALUE_ADDRESS (msymbol
);
2532 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
2535 svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr
);
2543 /* Read the ELF program headers from ABFD. Return the contents and
2544 set *PHDRS_SIZE to the size of the program headers. */
2547 read_program_headers_from_bfd (bfd
*abfd
, int *phdrs_size
)
2549 Elf_Internal_Ehdr
*ehdr
;
2552 ehdr
= elf_elfheader (abfd
);
2554 *phdrs_size
= ehdr
->e_phnum
* ehdr
->e_phentsize
;
2555 if (*phdrs_size
== 0)
2558 buf
= (gdb_byte
*) xmalloc (*phdrs_size
);
2559 if (bfd_seek (abfd
, ehdr
->e_phoff
, SEEK_SET
) != 0
2560 || bfd_bread (buf
, *phdrs_size
, abfd
) != *phdrs_size
)
2569 /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior
2570 exec_bfd. Otherwise return 0.
2572 We relocate all of the sections by the same amount. This
2573 behavior is mandated by recent editions of the System V ABI.
2574 According to the System V Application Binary Interface,
2575 Edition 4.1, page 5-5:
2577 ... Though the system chooses virtual addresses for
2578 individual processes, it maintains the segments' relative
2579 positions. Because position-independent code uses relative
2580 addressesing between segments, the difference between
2581 virtual addresses in memory must match the difference
2582 between virtual addresses in the file. The difference
2583 between the virtual address of any segment in memory and
2584 the corresponding virtual address in the file is thus a
2585 single constant value for any one executable or shared
2586 object in a given process. This difference is the base
2587 address. One use of the base address is to relocate the
2588 memory image of the program during dynamic linking.
2590 The same language also appears in Edition 4.0 of the System V
2591 ABI and is left unspecified in some of the earlier editions.
2593 Decide if the objfile needs to be relocated. As indicated above, we will
2594 only be here when execution is stopped. But during attachment PC can be at
2595 arbitrary address therefore regcache_read_pc can be misleading (contrary to
2596 the auxv AT_ENTRY value). Moreover for executable with interpreter section
2597 regcache_read_pc would point to the interpreter and not the main executable.
2599 So, to summarize, relocations are necessary when the start address obtained
2600 from the executable is different from the address in auxv AT_ENTRY entry.
2602 [ The astute reader will note that we also test to make sure that
2603 the executable in question has the DYNAMIC flag set. It is my
2604 opinion that this test is unnecessary (undesirable even). It
2605 was added to avoid inadvertent relocation of an executable
2606 whose e_type member in the ELF header is not ET_DYN. There may
2607 be a time in the future when it is desirable to do relocations
2608 on other types of files as well in which case this condition
2609 should either be removed or modified to accomodate the new file
2610 type. - Kevin, Nov 2000. ] */
2613 svr4_exec_displacement (CORE_ADDR
*displacementp
)
2615 /* ENTRY_POINT is a possible function descriptor - before
2616 a call to gdbarch_convert_from_func_ptr_addr. */
2617 CORE_ADDR entry_point
, exec_displacement
;
2619 if (exec_bfd
== NULL
)
2622 /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries
2623 being executed themselves and PIE (Position Independent Executable)
2624 executables are ET_DYN. */
2626 if ((bfd_get_file_flags (exec_bfd
) & DYNAMIC
) == 0)
2629 if (target_auxv_search (¤t_target
, AT_ENTRY
, &entry_point
) <= 0)
2632 exec_displacement
= entry_point
- bfd_get_start_address (exec_bfd
);
2634 /* Verify the EXEC_DISPLACEMENT candidate complies with the required page
2635 alignment. It is cheaper than the program headers comparison below. */
2637 if (bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
2639 const struct elf_backend_data
*elf
= get_elf_backend_data (exec_bfd
);
2641 /* p_align of PT_LOAD segments does not specify any alignment but
2642 only congruency of addresses:
2643 p_offset % p_align == p_vaddr % p_align
2644 Kernel is free to load the executable with lower alignment. */
2646 if ((exec_displacement
& (elf
->minpagesize
- 1)) != 0)
2650 /* Verify that the auxilliary vector describes the same file as exec_bfd, by
2651 comparing their program headers. If the program headers in the auxilliary
2652 vector do not match the program headers in the executable, then we are
2653 looking at a different file than the one used by the kernel - for
2654 instance, "gdb program" connected to "gdbserver :PORT ld.so program". */
2656 if (bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
2658 /* Be optimistic and clear OK only if GDB was able to verify the headers
2659 really do not match. */
2660 int phdrs_size
, phdrs2_size
, ok
= 1;
2661 gdb_byte
*buf
, *buf2
;
2664 buf
= read_program_header (-1, &phdrs_size
, &arch_size
, NULL
);
2665 buf2
= read_program_headers_from_bfd (exec_bfd
, &phdrs2_size
);
2666 if (buf
!= NULL
&& buf2
!= NULL
)
2668 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
2670 /* We are dealing with three different addresses. EXEC_BFD
2671 represents current address in on-disk file. target memory content
2672 may be different from EXEC_BFD as the file may have been prelinked
2673 to a different address after the executable has been loaded.
2674 Moreover the address of placement in target memory can be
2675 different from what the program headers in target memory say -
2676 this is the goal of PIE.
2678 Detected DISPLACEMENT covers both the offsets of PIE placement and
2679 possible new prelink performed after start of the program. Here
2680 relocate BUF and BUF2 just by the EXEC_BFD vs. target memory
2681 content offset for the verification purpose. */
2683 if (phdrs_size
!= phdrs2_size
2684 || bfd_get_arch_size (exec_bfd
) != arch_size
)
2686 else if (arch_size
== 32
2687 && phdrs_size
>= sizeof (Elf32_External_Phdr
)
2688 && phdrs_size
% sizeof (Elf32_External_Phdr
) == 0)
2690 Elf_Internal_Ehdr
*ehdr2
= elf_tdata (exec_bfd
)->elf_header
;
2691 Elf_Internal_Phdr
*phdr2
= elf_tdata (exec_bfd
)->phdr
;
2692 CORE_ADDR displacement
= 0;
2695 /* DISPLACEMENT could be found more easily by the difference of
2696 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2697 already have enough information to compute that displacement
2698 with what we've read. */
2700 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2701 if (phdr2
[i
].p_type
== PT_LOAD
)
2703 Elf32_External_Phdr
*phdrp
;
2704 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2705 CORE_ADDR vaddr
, paddr
;
2706 CORE_ADDR displacement_vaddr
= 0;
2707 CORE_ADDR displacement_paddr
= 0;
2709 phdrp
= &((Elf32_External_Phdr
*) buf
)[i
];
2710 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2711 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2713 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2715 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2717 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2719 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2721 if (displacement_vaddr
== displacement_paddr
)
2722 displacement
= displacement_vaddr
;
2727 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2729 for (i
= 0; i
< phdrs_size
/ sizeof (Elf32_External_Phdr
); i
++)
2731 Elf32_External_Phdr
*phdrp
;
2732 Elf32_External_Phdr
*phdr2p
;
2733 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2734 CORE_ADDR vaddr
, paddr
;
2735 asection
*plt2_asect
;
2737 phdrp
= &((Elf32_External_Phdr
*) buf
)[i
];
2738 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2739 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2740 phdr2p
= &((Elf32_External_Phdr
*) buf2
)[i
];
2742 /* PT_GNU_STACK is an exception by being never relocated by
2743 prelink as its addresses are always zero. */
2745 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2748 /* Check also other adjustment combinations - PR 11786. */
2750 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 4,
2752 vaddr
-= displacement
;
2753 store_unsigned_integer (buf_vaddr_p
, 4, byte_order
, vaddr
);
2755 paddr
= extract_unsigned_integer (buf_paddr_p
, 4,
2757 paddr
-= displacement
;
2758 store_unsigned_integer (buf_paddr_p
, 4, byte_order
, paddr
);
2760 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2763 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2764 CentOS-5 has problems with filesz, memsz as well.
2766 if (phdr2
[i
].p_type
== PT_GNU_RELRO
)
2768 Elf32_External_Phdr tmp_phdr
= *phdrp
;
2769 Elf32_External_Phdr tmp_phdr2
= *phdr2p
;
2771 memset (tmp_phdr
.p_filesz
, 0, 4);
2772 memset (tmp_phdr
.p_memsz
, 0, 4);
2773 memset (tmp_phdr
.p_flags
, 0, 4);
2774 memset (tmp_phdr
.p_align
, 0, 4);
2775 memset (tmp_phdr2
.p_filesz
, 0, 4);
2776 memset (tmp_phdr2
.p_memsz
, 0, 4);
2777 memset (tmp_phdr2
.p_flags
, 0, 4);
2778 memset (tmp_phdr2
.p_align
, 0, 4);
2780 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2785 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2786 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2790 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2793 content2
= (bfd_get_section_flags (exec_bfd
, plt2_asect
)
2794 & SEC_HAS_CONTENTS
) != 0;
2796 filesz
= extract_unsigned_integer (buf_filesz_p
, 4,
2799 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2800 FILESZ is from the in-memory image. */
2802 filesz
+= bfd_get_section_size (plt2_asect
);
2804 filesz
-= bfd_get_section_size (plt2_asect
);
2806 store_unsigned_integer (buf_filesz_p
, 4, byte_order
,
2809 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2817 else if (arch_size
== 64
2818 && phdrs_size
>= sizeof (Elf64_External_Phdr
)
2819 && phdrs_size
% sizeof (Elf64_External_Phdr
) == 0)
2821 Elf_Internal_Ehdr
*ehdr2
= elf_tdata (exec_bfd
)->elf_header
;
2822 Elf_Internal_Phdr
*phdr2
= elf_tdata (exec_bfd
)->phdr
;
2823 CORE_ADDR displacement
= 0;
2826 /* DISPLACEMENT could be found more easily by the difference of
2827 ehdr2->e_entry. But we haven't read the ehdr yet, and we
2828 already have enough information to compute that displacement
2829 with what we've read. */
2831 for (i
= 0; i
< ehdr2
->e_phnum
; i
++)
2832 if (phdr2
[i
].p_type
== PT_LOAD
)
2834 Elf64_External_Phdr
*phdrp
;
2835 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2836 CORE_ADDR vaddr
, paddr
;
2837 CORE_ADDR displacement_vaddr
= 0;
2838 CORE_ADDR displacement_paddr
= 0;
2840 phdrp
= &((Elf64_External_Phdr
*) buf
)[i
];
2841 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2842 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2844 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2846 displacement_vaddr
= vaddr
- phdr2
[i
].p_vaddr
;
2848 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2850 displacement_paddr
= paddr
- phdr2
[i
].p_paddr
;
2852 if (displacement_vaddr
== displacement_paddr
)
2853 displacement
= displacement_vaddr
;
2858 /* Now compare BUF and BUF2 with optional DISPLACEMENT. */
2860 for (i
= 0; i
< phdrs_size
/ sizeof (Elf64_External_Phdr
); i
++)
2862 Elf64_External_Phdr
*phdrp
;
2863 Elf64_External_Phdr
*phdr2p
;
2864 gdb_byte
*buf_vaddr_p
, *buf_paddr_p
;
2865 CORE_ADDR vaddr
, paddr
;
2866 asection
*plt2_asect
;
2868 phdrp
= &((Elf64_External_Phdr
*) buf
)[i
];
2869 buf_vaddr_p
= (gdb_byte
*) &phdrp
->p_vaddr
;
2870 buf_paddr_p
= (gdb_byte
*) &phdrp
->p_paddr
;
2871 phdr2p
= &((Elf64_External_Phdr
*) buf2
)[i
];
2873 /* PT_GNU_STACK is an exception by being never relocated by
2874 prelink as its addresses are always zero. */
2876 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2879 /* Check also other adjustment combinations - PR 11786. */
2881 vaddr
= extract_unsigned_integer (buf_vaddr_p
, 8,
2883 vaddr
-= displacement
;
2884 store_unsigned_integer (buf_vaddr_p
, 8, byte_order
, vaddr
);
2886 paddr
= extract_unsigned_integer (buf_paddr_p
, 8,
2888 paddr
-= displacement
;
2889 store_unsigned_integer (buf_paddr_p
, 8, byte_order
, paddr
);
2891 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2894 /* Strip modifies the flags and alignment of PT_GNU_RELRO.
2895 CentOS-5 has problems with filesz, memsz as well.
2897 if (phdr2
[i
].p_type
== PT_GNU_RELRO
)
2899 Elf64_External_Phdr tmp_phdr
= *phdrp
;
2900 Elf64_External_Phdr tmp_phdr2
= *phdr2p
;
2902 memset (tmp_phdr
.p_filesz
, 0, 8);
2903 memset (tmp_phdr
.p_memsz
, 0, 8);
2904 memset (tmp_phdr
.p_flags
, 0, 4);
2905 memset (tmp_phdr
.p_align
, 0, 8);
2906 memset (tmp_phdr2
.p_filesz
, 0, 8);
2907 memset (tmp_phdr2
.p_memsz
, 0, 8);
2908 memset (tmp_phdr2
.p_flags
, 0, 4);
2909 memset (tmp_phdr2
.p_align
, 0, 8);
2911 if (memcmp (&tmp_phdr
, &tmp_phdr2
, sizeof (tmp_phdr
))
2916 /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */
2917 plt2_asect
= bfd_get_section_by_name (exec_bfd
, ".plt");
2921 gdb_byte
*buf_filesz_p
= (gdb_byte
*) &phdrp
->p_filesz
;
2924 content2
= (bfd_get_section_flags (exec_bfd
, plt2_asect
)
2925 & SEC_HAS_CONTENTS
) != 0;
2927 filesz
= extract_unsigned_integer (buf_filesz_p
, 8,
2930 /* PLT2_ASECT is from on-disk file (exec_bfd) while
2931 FILESZ is from the in-memory image. */
2933 filesz
+= bfd_get_section_size (plt2_asect
);
2935 filesz
-= bfd_get_section_size (plt2_asect
);
2937 store_unsigned_integer (buf_filesz_p
, 8, byte_order
,
2940 if (memcmp (phdrp
, phdr2p
, sizeof (*phdrp
)) == 0)
2961 /* It can be printed repeatedly as there is no easy way to check
2962 the executable symbols/file has been already relocated to
2965 printf_unfiltered (_("Using PIE (Position Independent Executable) "
2966 "displacement %s for \"%s\".\n"),
2967 paddress (target_gdbarch (), exec_displacement
),
2968 bfd_get_filename (exec_bfd
));
2971 *displacementp
= exec_displacement
;
2975 /* Relocate the main executable. This function should be called upon
2976 stopping the inferior process at the entry point to the program.
2977 The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
2978 different, the main executable is relocated by the proper amount. */
2981 svr4_relocate_main_executable (void)
2983 CORE_ADDR displacement
;
2985 /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS
2986 probably contains the offsets computed using the PIE displacement
2987 from the previous run, which of course are irrelevant for this run.
2988 So we need to determine the new PIE displacement and recompute the
2989 section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS
2990 already contains pre-computed offsets.
2992 If we cannot compute the PIE displacement, either:
2994 - The executable is not PIE.
2996 - SYMFILE_OBJFILE does not match the executable started in the target.
2997 This can happen for main executable symbols loaded at the host while
2998 `ld.so --ld-args main-executable' is loaded in the target.
3000 Then we leave the section offsets untouched and use them as is for
3003 - These section offsets were properly reset earlier, and thus
3004 already contain the correct values. This can happen for instance
3005 when reconnecting via the remote protocol to a target that supports
3006 the `qOffsets' packet.
3008 - The section offsets were not reset earlier, and the best we can
3009 hope is that the old offsets are still applicable to the new run. */
3011 if (! svr4_exec_displacement (&displacement
))
3014 /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file
3017 if (symfile_objfile
)
3019 struct section_offsets
*new_offsets
;
3022 new_offsets
= XALLOCAVEC (struct section_offsets
,
3023 symfile_objfile
->num_sections
);
3025 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
3026 new_offsets
->offsets
[i
] = displacement
;
3028 objfile_relocate (symfile_objfile
, new_offsets
);
3034 for (asect
= exec_bfd
->sections
; asect
!= NULL
; asect
= asect
->next
)
3035 exec_set_section_address (bfd_get_filename (exec_bfd
), asect
->index
,
3036 (bfd_section_vma (exec_bfd
, asect
)
3041 /* Implement the "create_inferior_hook" target_solib_ops method.
3043 For SVR4 executables, this first instruction is either the first
3044 instruction in the dynamic linker (for dynamically linked
3045 executables) or the instruction at "start" for statically linked
3046 executables. For dynamically linked executables, the system
3047 first exec's /lib/libc.so.N, which contains the dynamic linker,
3048 and starts it running. The dynamic linker maps in any needed
3049 shared libraries, maps in the actual user executable, and then
3050 jumps to "start" in the user executable.
3052 We can arrange to cooperate with the dynamic linker to discover the
3053 names of shared libraries that are dynamically linked, and the base
3054 addresses to which they are linked.
3056 This function is responsible for discovering those names and
3057 addresses, and saving sufficient information about them to allow
3058 their symbols to be read at a later time. */
3061 svr4_solib_create_inferior_hook (int from_tty
)
3063 struct svr4_info
*info
;
3065 info
= get_svr4_info ();
3067 /* Clear the probes-based interface's state. */
3068 free_probes_table (info
);
3069 free_solib_list (info
);
3071 /* Relocate the main executable if necessary. */
3072 svr4_relocate_main_executable ();
3074 /* No point setting a breakpoint in the dynamic linker if we can't
3075 hit it (e.g., a core file, or a trace file). */
3076 if (!target_has_execution
)
3079 if (!svr4_have_link_map_offsets ())
3082 if (!enable_break (info
, from_tty
))
3087 svr4_clear_solib (void)
3089 struct svr4_info
*info
;
3091 info
= get_svr4_info ();
3092 info
->debug_base
= 0;
3093 info
->debug_loader_offset_p
= 0;
3094 info
->debug_loader_offset
= 0;
3095 xfree (info
->debug_loader_name
);
3096 info
->debug_loader_name
= NULL
;
3099 /* Clear any bits of ADDR that wouldn't fit in a target-format
3100 data pointer. "Data pointer" here refers to whatever sort of
3101 address the dynamic linker uses to manage its sections. At the
3102 moment, we don't support shared libraries on any processors where
3103 code and data pointers are different sizes.
3105 This isn't really the right solution. What we really need here is
3106 a way to do arithmetic on CORE_ADDR values that respects the
3107 natural pointer/address correspondence. (For example, on the MIPS,
3108 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
3109 sign-extend the value. There, simply truncating the bits above
3110 gdbarch_ptr_bit, as we do below, is no good.) This should probably
3111 be a new gdbarch method or something. */
3113 svr4_truncate_ptr (CORE_ADDR addr
)
3115 if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR
) * 8)
3116 /* We don't need to truncate anything, and the bit twiddling below
3117 will fail due to overflow problems. */
3120 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1);
3125 svr4_relocate_section_addresses (struct so_list
*so
,
3126 struct target_section
*sec
)
3128 bfd
*abfd
= sec
->the_bfd_section
->owner
;
3130 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ lm_addr_check (so
, abfd
));
3131 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ lm_addr_check (so
, abfd
));
3135 /* Architecture-specific operations. */
3137 /* Per-architecture data key. */
3138 static struct gdbarch_data
*solib_svr4_data
;
3140 struct solib_svr4_ops
3142 /* Return a description of the layout of `struct link_map'. */
3143 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
3146 /* Return a default for the architecture-specific operations. */
3149 solib_svr4_init (struct obstack
*obstack
)
3151 struct solib_svr4_ops
*ops
;
3153 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
3154 ops
->fetch_link_map_offsets
= NULL
;
3158 /* Set the architecture-specific `struct link_map_offsets' fetcher for
3159 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
3162 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
3163 struct link_map_offsets
*(*flmo
) (void))
3165 struct solib_svr4_ops
*ops
3166 = (struct solib_svr4_ops
*) gdbarch_data (gdbarch
, solib_svr4_data
);
3168 ops
->fetch_link_map_offsets
= flmo
;
3170 set_solib_ops (gdbarch
, &svr4_so_ops
);
3173 /* Fetch a link_map_offsets structure using the architecture-specific
3174 `struct link_map_offsets' fetcher. */
3176 static struct link_map_offsets
*
3177 svr4_fetch_link_map_offsets (void)
3179 struct solib_svr4_ops
*ops
3180 = (struct solib_svr4_ops
*) gdbarch_data (target_gdbarch (),
3183 gdb_assert (ops
->fetch_link_map_offsets
);
3184 return ops
->fetch_link_map_offsets ();
3187 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
3190 svr4_have_link_map_offsets (void)
3192 struct solib_svr4_ops
*ops
3193 = (struct solib_svr4_ops
*) gdbarch_data (target_gdbarch (),
3196 return (ops
->fetch_link_map_offsets
!= NULL
);
3200 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
3201 `struct r_debug' and a `struct link_map' that are binary compatible
3202 with the origional SVR4 implementation. */
3204 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3205 for an ILP32 SVR4 system. */
3207 struct link_map_offsets
*
3208 svr4_ilp32_fetch_link_map_offsets (void)
3210 static struct link_map_offsets lmo
;
3211 static struct link_map_offsets
*lmp
= NULL
;
3217 lmo
.r_version_offset
= 0;
3218 lmo
.r_version_size
= 4;
3219 lmo
.r_map_offset
= 4;
3220 lmo
.r_brk_offset
= 8;
3221 lmo
.r_ldsomap_offset
= 20;
3223 /* Everything we need is in the first 20 bytes. */
3224 lmo
.link_map_size
= 20;
3225 lmo
.l_addr_offset
= 0;
3226 lmo
.l_name_offset
= 4;
3227 lmo
.l_ld_offset
= 8;
3228 lmo
.l_next_offset
= 12;
3229 lmo
.l_prev_offset
= 16;
3235 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
3236 for an LP64 SVR4 system. */
3238 struct link_map_offsets
*
3239 svr4_lp64_fetch_link_map_offsets (void)
3241 static struct link_map_offsets lmo
;
3242 static struct link_map_offsets
*lmp
= NULL
;
3248 lmo
.r_version_offset
= 0;
3249 lmo
.r_version_size
= 4;
3250 lmo
.r_map_offset
= 8;
3251 lmo
.r_brk_offset
= 16;
3252 lmo
.r_ldsomap_offset
= 40;
3254 /* Everything we need is in the first 40 bytes. */
3255 lmo
.link_map_size
= 40;
3256 lmo
.l_addr_offset
= 0;
3257 lmo
.l_name_offset
= 8;
3258 lmo
.l_ld_offset
= 16;
3259 lmo
.l_next_offset
= 24;
3260 lmo
.l_prev_offset
= 32;
3267 struct target_so_ops svr4_so_ops
;
3269 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
3270 different rule for symbol lookup. The lookup begins here in the DSO, not in
3271 the main executable. */
3273 static struct block_symbol
3274 elf_lookup_lib_symbol (struct objfile
*objfile
,
3276 const domain_enum domain
)
3280 if (objfile
== symfile_objfile
)
3284 /* OBJFILE should have been passed as the non-debug one. */
3285 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
3287 abfd
= objfile
->obfd
;
3290 if (abfd
== NULL
|| scan_dyntag (DT_SYMBOLIC
, abfd
, NULL
, NULL
) != 1)
3291 return (struct block_symbol
) {NULL
, NULL
};
3293 return lookup_global_symbol_from_objfile (objfile
, name
, domain
);
3297 _initialize_svr4_solib (void)
3299 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
3300 solib_svr4_pspace_data
3301 = register_program_space_data_with_cleanup (NULL
, svr4_pspace_data_cleanup
);
3303 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
3304 svr4_so_ops
.free_so
= svr4_free_so
;
3305 svr4_so_ops
.clear_so
= svr4_clear_so
;
3306 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
3307 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
3308 svr4_so_ops
.current_sos
= svr4_current_sos
;
3309 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
3310 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
3311 svr4_so_ops
.bfd_open
= solib_bfd_open
;
3312 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
3313 svr4_so_ops
.same
= svr4_same
;
3314 svr4_so_ops
.keep_data_in_core
= svr4_keep_data_in_core
;
3315 svr4_so_ops
.update_breakpoints
= svr4_update_solib_event_breakpoints
;
3316 svr4_so_ops
.handle_event
= svr4_handle_solib_event
;