1 /* Handle SVR4 shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
4 2001, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "elf/external.h"
24 #include "elf/common.h"
35 #include "gdb_assert.h"
39 #include "solib-svr4.h"
41 #include "bfd-target.h"
45 #include "exceptions.h"
47 static struct link_map_offsets
*svr4_fetch_link_map_offsets (void);
48 static int svr4_have_link_map_offsets (void);
50 /* Link map info to include in an allocated so_list entry */
54 /* Pointer to copy of link map from inferior. The type is char *
55 rather than void *, so that we may use byte offsets to find the
56 various fields without the need for a cast. */
59 /* Amount by which addresses in the binary should be relocated to
60 match the inferior. This could most often be taken directly
61 from lm, but when prelinking is involved and the prelink base
62 address changes, we may need a different offset, we want to
63 warn about the difference and compute it only once. */
66 /* The target location of lm. */
70 /* On SVR4 systems, a list of symbols in the dynamic linker where
71 GDB can try to place a breakpoint to monitor shared library
74 If none of these symbols are found, or other errors occur, then
75 SVR4 systems will fall back to using a symbol as the "startup
76 mapping complete" breakpoint address. */
78 static char *solib_break_names
[] =
89 static char *bkpt_names
[] =
97 static char *main_name_list
[] =
103 /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
104 the same shared library. */
107 svr4_same_1 (const char *gdb_so_name
, const char *inferior_so_name
)
109 if (strcmp (gdb_so_name
, inferior_so_name
) == 0)
112 /* On Solaris, when starting inferior we think that dynamic linker is
113 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
114 contains /lib/ld.so.1. Sometimes one file is a link to another, but
115 sometimes they have identical content, but are not linked to each
116 other. We don't restrict this check for Solaris, but the chances
117 of running into this situation elsewhere are very low. */
118 if (strcmp (gdb_so_name
, "/usr/lib/ld.so.1") == 0
119 && strcmp (inferior_so_name
, "/lib/ld.so.1") == 0)
122 /* Similarly, we observed the same issue with sparc64, but with
123 different locations. */
124 if (strcmp (gdb_so_name
, "/usr/lib/sparcv9/ld.so.1") == 0
125 && strcmp (inferior_so_name
, "/lib/sparcv9/ld.so.1") == 0)
132 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
134 return (svr4_same_1 (gdb
->so_original_name
, inferior
->so_original_name
));
137 /* link map access functions */
140 LM_ADDR_FROM_LINK_MAP (struct so_list
*so
)
142 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
144 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_addr_offset
,
145 builtin_type_void_data_ptr
);
149 HAS_LM_DYNAMIC_FROM_LINK_MAP ()
151 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
153 return lmo
->l_ld_offset
>= 0;
157 LM_DYNAMIC_FROM_LINK_MAP (struct so_list
*so
)
159 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
161 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_ld_offset
,
162 builtin_type_void_data_ptr
);
166 LM_ADDR_CHECK (struct so_list
*so
, bfd
*abfd
)
168 if (so
->lm_info
->l_addr
== (CORE_ADDR
)-1)
170 struct bfd_section
*dyninfo_sect
;
171 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
, align
= 0x1000;
173 l_addr
= LM_ADDR_FROM_LINK_MAP (so
);
175 if (! abfd
|| ! HAS_LM_DYNAMIC_FROM_LINK_MAP ())
178 l_dynaddr
= LM_DYNAMIC_FROM_LINK_MAP (so
);
180 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
181 if (dyninfo_sect
== NULL
)
184 dynaddr
= bfd_section_vma (abfd
, dyninfo_sect
);
186 if (dynaddr
+ l_addr
!= l_dynaddr
)
188 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
190 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
191 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
196 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
197 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
198 align
= phdr
[i
].p_align
;
201 /* Turn it into a mask. */
204 /* If the changes match the alignment requirements, we
205 assume we're using a core file that was generated by the
206 same binary, just prelinked with a different base offset.
207 If it doesn't match, we may have a different binary, the
208 same binary with the dynamic table loaded at an unrelated
209 location, or anything, really. To avoid regressions,
210 don't adjust the base offset in the latter case, although
211 odds are that, if things really changed, debugging won't
213 if ((l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
215 l_addr
= l_dynaddr
- dynaddr
;
217 warning (_(".dynamic section for \"%s\" "
218 "is not at the expected address"), so
->so_name
);
219 warning (_("difference appears to be caused by prelink, "
220 "adjusting expectations"));
223 warning (_(".dynamic section for \"%s\" "
224 "is not at the expected address "
225 "(wrong library or version mismatch?)"), so
->so_name
);
229 so
->lm_info
->l_addr
= l_addr
;
232 return so
->lm_info
->l_addr
;
236 LM_NEXT (struct so_list
*so
)
238 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
240 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_next_offset
,
241 builtin_type_void_data_ptr
);
245 LM_NAME (struct so_list
*so
)
247 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
249 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_name_offset
,
250 builtin_type_void_data_ptr
);
254 IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list
*so
)
256 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
258 /* Assume that everything is a library if the dynamic loader was loaded
259 late by a static executable. */
260 if (bfd_get_section_by_name (exec_bfd
, ".dynamic") == NULL
)
263 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_prev_offset
,
264 builtin_type_void_data_ptr
) == 0;
267 static CORE_ADDR debug_base
; /* Base of dynamic linker structures */
269 /* Validity flag for debug_loader_offset. */
270 static int debug_loader_offset_p
;
272 /* Load address for the dynamic linker, inferred. */
273 static CORE_ADDR debug_loader_offset
;
275 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
276 static char *debug_loader_name
;
278 /* Load map address for the main executable. */
279 static CORE_ADDR main_lm_addr
;
281 /* Local function prototypes */
283 static int match_main (char *);
285 static CORE_ADDR
bfd_lookup_symbol (bfd
*, char *);
291 bfd_lookup_symbol -- lookup the value for a specific symbol
295 CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
299 An expensive way to lookup the value of a single symbol for
300 bfd's that are only temporary anyway. This is used by the
301 shared library support to find the address of the debugger
302 notification routine in the shared library.
304 The returned symbol may be in a code or data section; functions
305 will normally be in a code section, but may be in a data section
306 if this architecture uses function descriptors.
308 Note that 0 is specifically allowed as an error return (no
313 bfd_lookup_symbol (bfd
*abfd
, char *symname
)
317 asymbol
**symbol_table
;
318 unsigned int number_of_symbols
;
320 struct cleanup
*back_to
;
321 CORE_ADDR symaddr
= 0;
323 storage_needed
= bfd_get_symtab_upper_bound (abfd
);
325 if (storage_needed
> 0)
327 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
328 back_to
= make_cleanup (xfree
, symbol_table
);
329 number_of_symbols
= bfd_canonicalize_symtab (abfd
, symbol_table
);
331 for (i
= 0; i
< number_of_symbols
; i
++)
333 sym
= *symbol_table
++;
334 if (strcmp (sym
->name
, symname
) == 0
335 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0)
337 /* BFD symbols are section relative. */
338 symaddr
= sym
->value
+ sym
->section
->vma
;
342 do_cleanups (back_to
);
348 /* On FreeBSD, the dynamic linker is stripped by default. So we'll
349 have to check the dynamic string table too. */
351 storage_needed
= bfd_get_dynamic_symtab_upper_bound (abfd
);
353 if (storage_needed
> 0)
355 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
356 back_to
= make_cleanup (xfree
, symbol_table
);
357 number_of_symbols
= bfd_canonicalize_dynamic_symtab (abfd
, symbol_table
);
359 for (i
= 0; i
< number_of_symbols
; i
++)
361 sym
= *symbol_table
++;
363 if (strcmp (sym
->name
, symname
) == 0
364 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0)
366 /* BFD symbols are section relative. */
367 symaddr
= sym
->value
+ sym
->section
->vma
;
371 do_cleanups (back_to
);
377 /* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is
378 returned and the corresponding PTR is set. */
381 scan_dyntag (int dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
)
383 int arch_size
, step
, sect_size
;
385 CORE_ADDR dyn_ptr
, dyn_addr
;
386 gdb_byte
*bufend
, *bufstart
, *buf
;
387 Elf32_External_Dyn
*x_dynp_32
;
388 Elf64_External_Dyn
*x_dynp_64
;
389 struct bfd_section
*sect
;
393 arch_size
= bfd_get_arch_size (abfd
);
397 /* Find the start address of the .dynamic section. */
398 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
401 dyn_addr
= bfd_section_vma (abfd
, sect
);
403 /* Read in .dynamic from the BFD. We will get the actual value
404 from memory later. */
405 sect_size
= bfd_section_size (abfd
, sect
);
406 buf
= bufstart
= alloca (sect_size
);
407 if (!bfd_get_section_contents (abfd
, sect
,
411 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
412 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
413 : sizeof (Elf64_External_Dyn
);
414 for (bufend
= buf
+ sect_size
;
420 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
421 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
422 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
426 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
427 dyn_tag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
428 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
430 if (dyn_tag
== DT_NULL
)
432 if (dyn_tag
== dyntag
)
434 /* If requested, try to read the runtime value of this .dynamic
441 ptr_addr
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
442 if (target_read_memory (ptr_addr
, ptr_buf
, arch_size
/ 8) == 0)
443 dyn_ptr
= extract_typed_address (ptr_buf
,
444 builtin_type_void_data_ptr
);
459 elf_locate_base -- locate the base address of dynamic linker structs
460 for SVR4 elf targets.
464 CORE_ADDR elf_locate_base (void)
468 For SVR4 elf targets the address of the dynamic linker's runtime
469 structure is contained within the dynamic info section in the
470 executable file. The dynamic section is also mapped into the
471 inferior address space. Because the runtime loader fills in the
472 real address before starting the inferior, we have to read in the
473 dynamic info section from the inferior address space.
474 If there are any errors while trying to find the address, we
475 silently return 0, otherwise the found address is returned.
480 elf_locate_base (void)
482 struct minimal_symbol
*msymbol
;
485 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
486 instead of DT_DEBUG, although they sometimes contain an unused
488 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
))
491 int pbuf_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
492 pbuf
= alloca (pbuf_size
);
493 /* DT_MIPS_RLD_MAP contains a pointer to the address
494 of the dynamic link structure. */
495 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
497 return extract_typed_address (pbuf
, builtin_type_void_data_ptr
);
501 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
))
504 /* This may be a static executable. Look for the symbol
505 conventionally named _r_debug, as a last resort. */
506 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
508 return SYMBOL_VALUE_ADDRESS (msymbol
);
510 /* DT_DEBUG entry not found. */
518 locate_base -- locate the base address of dynamic linker structs
522 CORE_ADDR locate_base (void)
526 For both the SunOS and SVR4 shared library implementations, if the
527 inferior executable has been linked dynamically, there is a single
528 address somewhere in the inferior's data space which is the key to
529 locating all of the dynamic linker's runtime structures. This
530 address is the value of the debug base symbol. The job of this
531 function is to find and return that address, or to return 0 if there
532 is no such address (the executable is statically linked for example).
534 For SunOS, the job is almost trivial, since the dynamic linker and
535 all of it's structures are statically linked to the executable at
536 link time. Thus the symbol for the address we are looking for has
537 already been added to the minimal symbol table for the executable's
538 objfile at the time the symbol file's symbols were read, and all we
539 have to do is look it up there. Note that we explicitly do NOT want
540 to find the copies in the shared library.
542 The SVR4 version is a bit more complicated because the address
543 is contained somewhere in the dynamic info section. We have to go
544 to a lot more work to discover the address of the debug base symbol.
545 Because of this complexity, we cache the value we find and return that
546 value on subsequent invocations. Note there is no copy in the
547 executable symbol tables.
554 /* Check to see if we have a currently valid address, and if so, avoid
555 doing all this work again and just return the cached address. If
556 we have no cached address, try to locate it in the dynamic info
557 section for ELF executables. There's no point in doing any of this
558 though if we don't have some link map offsets to work with. */
560 if (debug_base
== 0 && svr4_have_link_map_offsets ())
563 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
564 debug_base
= elf_locate_base ();
569 /* Find the first element in the inferior's dynamic link map, and
570 return its address in the inferior.
572 FIXME: Perhaps we should validate the info somehow, perhaps by
573 checking r_version for a known version number, or r_state for
577 solib_svr4_r_map (void)
579 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
581 return read_memory_typed_address (debug_base
+ lmo
->r_map_offset
,
582 builtin_type_void_data_ptr
);
585 /* Find r_brk from the inferior's debug base. */
588 solib_svr4_r_brk (void)
590 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
592 return read_memory_typed_address (debug_base
+ lmo
->r_brk_offset
,
593 builtin_type_void_data_ptr
);
596 /* Find the link map for the dynamic linker (if it is not in the
597 normal list of loaded shared objects). */
600 solib_svr4_r_ldsomap (void)
602 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
605 /* Check version, and return zero if `struct r_debug' doesn't have
606 the r_ldsomap member. */
607 version
= read_memory_unsigned_integer (debug_base
+ lmo
->r_version_offset
,
608 lmo
->r_version_size
);
609 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
612 return read_memory_typed_address (debug_base
+ lmo
->r_ldsomap_offset
,
613 builtin_type_void_data_ptr
);
620 open_symbol_file_object
624 void open_symbol_file_object (void *from_tty)
628 If no open symbol file, attempt to locate and open the main symbol
629 file. On SVR4 systems, this is the first link map entry. If its
630 name is here, we can open it. Useful when attaching to a process
631 without first loading its symbol file.
633 If FROM_TTYP dereferences to a non-zero integer, allow messages to
634 be printed. This parameter is a pointer rather than an int because
635 open_symbol_file_object() is called via catch_errors() and
636 catch_errors() requires a pointer argument. */
639 open_symbol_file_object (void *from_ttyp
)
641 CORE_ADDR lm
, l_name
;
644 int from_tty
= *(int *)from_ttyp
;
645 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
646 int l_name_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
647 gdb_byte
*l_name_buf
= xmalloc (l_name_size
);
648 struct cleanup
*cleanups
= make_cleanup (xfree
, l_name_buf
);
651 if (!query ("Attempt to reload symbols from process? "))
654 /* Always locate the debug struct, in case it has moved. */
656 if (locate_base () == 0)
657 return 0; /* failed somehow... */
659 /* First link map member should be the executable. */
660 lm
= solib_svr4_r_map ();
662 return 0; /* failed somehow... */
664 /* Read address of name from target memory to GDB. */
665 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
667 /* Convert the address to host format. */
668 l_name
= extract_typed_address (l_name_buf
, builtin_type_void_data_ptr
);
670 /* Free l_name_buf. */
671 do_cleanups (cleanups
);
674 return 0; /* No filename. */
676 /* Now fetch the filename from target memory. */
677 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
678 make_cleanup (xfree
, filename
);
682 warning (_("failed to read exec filename from attached file: %s"),
683 safe_strerror (errcode
));
687 /* Have a pathname: read the symbol file. */
688 symbol_file_add_main (filename
, from_tty
);
693 /* If no shared library information is available from the dynamic
694 linker, build a fallback list from other sources. */
696 static struct so_list
*
697 svr4_default_sos (void)
699 struct so_list
*head
= NULL
;
700 struct so_list
**link_ptr
= &head
;
702 if (debug_loader_offset_p
)
704 struct so_list
*new = XZALLOC (struct so_list
);
706 new->lm_info
= xmalloc (sizeof (struct lm_info
));
708 /* Nothing will ever check the cached copy of the link
709 map if we set l_addr. */
710 new->lm_info
->l_addr
= debug_loader_offset
;
711 new->lm_info
->lm_addr
= 0;
712 new->lm_info
->lm
= NULL
;
714 strncpy (new->so_name
, debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
715 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
716 strcpy (new->so_original_name
, new->so_name
);
719 link_ptr
= &new->next
;
727 current_sos -- build a list of currently loaded shared objects
731 struct so_list *current_sos ()
735 Build a list of `struct so_list' objects describing the shared
736 objects currently loaded in the inferior. This list does not
737 include an entry for the main executable file.
739 Note that we only gather information directly available from the
740 inferior --- we don't examine any of the shared library files
741 themselves. The declaration of `struct so_list' says which fields
742 we provide values for. */
744 static struct so_list
*
745 svr4_current_sos (void)
748 struct so_list
*head
= 0;
749 struct so_list
**link_ptr
= &head
;
750 CORE_ADDR ldsomap
= 0;
752 /* Always locate the debug struct, in case it has moved. */
756 /* If we can't find the dynamic linker's base structure, this
757 must not be a dynamically linked executable. Hmm. */
759 return svr4_default_sos ();
761 /* Walk the inferior's link map list, and build our list of
762 `struct so_list' nodes. */
763 lm
= solib_svr4_r_map ();
767 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
768 struct so_list
*new = XZALLOC (struct so_list
);
769 struct cleanup
*old_chain
= make_cleanup (xfree
, new);
771 new->lm_info
= xmalloc (sizeof (struct lm_info
));
772 make_cleanup (xfree
, new->lm_info
);
774 new->lm_info
->l_addr
= (CORE_ADDR
)-1;
775 new->lm_info
->lm_addr
= lm
;
776 new->lm_info
->lm
= xzalloc (lmo
->link_map_size
);
777 make_cleanup (xfree
, new->lm_info
->lm
);
779 read_memory (lm
, new->lm_info
->lm
, lmo
->link_map_size
);
783 /* For SVR4 versions, the first entry in the link map is for the
784 inferior executable, so we must ignore it. For some versions of
785 SVR4, it has no name. For others (Solaris 2.3 for example), it
786 does have a name, so we can no longer use a missing name to
787 decide when to ignore it. */
788 if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap
== 0)
790 main_lm_addr
= new->lm_info
->lm_addr
;
798 /* Extract this shared object's name. */
799 target_read_string (LM_NAME (new), &buffer
,
800 SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
802 warning (_("Can't read pathname for load map: %s."),
803 safe_strerror (errcode
));
806 strncpy (new->so_name
, buffer
, SO_NAME_MAX_PATH_SIZE
- 1);
807 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
808 strcpy (new->so_original_name
, new->so_name
);
812 /* If this entry has no name, or its name matches the name
813 for the main executable, don't include it in the list. */
814 if (! new->so_name
[0]
815 || match_main (new->so_name
))
821 link_ptr
= &new->next
;
825 /* On Solaris, the dynamic linker is not in the normal list of
826 shared objects, so make sure we pick it up too. Having
827 symbol information for the dynamic linker is quite crucial
828 for skipping dynamic linker resolver code. */
829 if (lm
== 0 && ldsomap
== 0)
830 lm
= ldsomap
= solib_svr4_r_ldsomap ();
832 discard_cleanups (old_chain
);
836 return svr4_default_sos ();
841 /* Get the address of the link_map for a given OBJFILE. */
844 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
848 /* Cause svr4_current_sos() to be run if it hasn't been already. */
849 if (main_lm_addr
== 0)
850 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
852 /* svr4_current_sos() will set main_lm_addr for the main executable. */
853 if (objfile
== symfile_objfile
)
856 /* The other link map addresses may be found by examining the list
857 of shared libraries. */
858 for (so
= master_so_list (); so
; so
= so
->next
)
859 if (so
->objfile
== objfile
)
860 return so
->lm_info
->lm_addr
;
866 /* On some systems, the only way to recognize the link map entry for
867 the main executable file is by looking at its name. Return
868 non-zero iff SONAME matches one of the known main executable names. */
871 match_main (char *soname
)
875 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
877 if (strcmp (soname
, *mainp
) == 0)
884 /* Return 1 if PC lies in the dynamic symbol resolution code of the
885 SVR4 run time loader. */
886 static CORE_ADDR interp_text_sect_low
;
887 static CORE_ADDR interp_text_sect_high
;
888 static CORE_ADDR interp_plt_sect_low
;
889 static CORE_ADDR interp_plt_sect_high
;
892 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
894 return ((pc
>= interp_text_sect_low
&& pc
< interp_text_sect_high
)
895 || (pc
>= interp_plt_sect_low
&& pc
< interp_plt_sect_high
)
896 || in_plt_section (pc
, NULL
));
899 /* Given an executable's ABFD and target, compute the entry-point
903 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
905 /* KevinB wrote ... for most targets, the address returned by
906 bfd_get_start_address() is the entry point for the start
907 function. But, for some targets, bfd_get_start_address() returns
908 the address of a function descriptor from which the entry point
909 address may be extracted. This address is extracted by
910 gdbarch_convert_from_func_ptr_addr(). The method
911 gdbarch_convert_from_func_ptr_addr() is the merely the identify
912 function for targets which don't use function descriptors. */
913 return gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
914 bfd_get_start_address (abfd
),
922 enable_break -- arrange for dynamic linker to hit breakpoint
926 int enable_break (void)
930 Both the SunOS and the SVR4 dynamic linkers have, as part of their
931 debugger interface, support for arranging for the inferior to hit
932 a breakpoint after mapping in the shared libraries. This function
933 enables that breakpoint.
935 For SunOS, there is a special flag location (in_debugger) which we
936 set to 1. When the dynamic linker sees this flag set, it will set
937 a breakpoint at a location known only to itself, after saving the
938 original contents of that place and the breakpoint address itself,
939 in it's own internal structures. When we resume the inferior, it
940 will eventually take a SIGTRAP when it runs into the breakpoint.
941 We handle this (in a different place) by restoring the contents of
942 the breakpointed location (which is only known after it stops),
943 chasing around to locate the shared libraries that have been
944 loaded, then resuming.
946 For SVR4, the debugger interface structure contains a member (r_brk)
947 which is statically initialized at the time the shared library is
948 built, to the offset of a function (_r_debug_state) which is guaran-
949 teed to be called once before mapping in a library, and again when
950 the mapping is complete. At the time we are examining this member,
951 it contains only the unrelocated offset of the function, so we have
952 to do our own relocation. Later, when the dynamic linker actually
953 runs, it relocates r_brk to be the actual address of _r_debug_state().
955 The debugger interface structure also contains an enumeration which
956 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
957 depending upon whether or not the library is being mapped or unmapped,
958 and then set to RT_CONSISTENT after the library is mapped/unmapped.
964 struct minimal_symbol
*msymbol
;
966 asection
*interp_sect
;
969 /* First, remove all the solib event breakpoints. Their addresses
970 may have changed since the last time we ran the program. */
971 remove_solib_event_breakpoints ();
973 interp_text_sect_low
= interp_text_sect_high
= 0;
974 interp_plt_sect_low
= interp_plt_sect_high
= 0;
976 /* If we already have a shared library list in the target, and
977 r_debug contains r_brk, set the breakpoint there - this should
978 mean r_brk has already been relocated. Assume the dynamic linker
979 is the object containing r_brk. */
981 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
983 if (debug_base
&& solib_svr4_r_map () != 0)
984 sym_addr
= solib_svr4_r_brk ();
988 struct obj_section
*os
;
990 sym_addr
= gdbarch_addr_bits_remove
991 (target_gdbarch
, gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
995 os
= find_pc_section (sym_addr
);
998 /* Record the relocated start and end address of the dynamic linker
999 text and plt section for svr4_in_dynsym_resolve_code. */
1001 CORE_ADDR load_addr
;
1003 tmp_bfd
= os
->objfile
->obfd
;
1004 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
1005 os
->objfile
->sect_index_text
);
1007 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1010 interp_text_sect_low
=
1011 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1012 interp_text_sect_high
=
1013 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1015 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1018 interp_plt_sect_low
=
1019 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1020 interp_plt_sect_high
=
1021 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1024 create_solib_event_breakpoint (sym_addr
);
1029 /* Find the .interp section; if not found, warn the user and drop
1030 into the old breakpoint at symbol code. */
1031 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
1034 unsigned int interp_sect_size
;
1036 CORE_ADDR load_addr
= 0;
1037 int load_addr_found
= 0;
1038 int loader_found_in_list
= 0;
1040 bfd
*tmp_bfd
= NULL
;
1041 struct target_ops
*tmp_bfd_target
;
1042 volatile struct gdb_exception ex
;
1044 /* Read the contents of the .interp section into a local buffer;
1045 the contents specify the dynamic linker this program uses. */
1047 interp_sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
1048 buf
= alloca (interp_sect_size
);
1049 bfd_get_section_contents (exec_bfd
, interp_sect
,
1050 buf
, 0, interp_sect_size
);
1052 /* Now we need to figure out where the dynamic linker was
1053 loaded so that we can load its symbols and place a breakpoint
1054 in the dynamic linker itself.
1056 This address is stored on the stack. However, I've been unable
1057 to find any magic formula to find it for Solaris (appears to
1058 be trivial on GNU/Linux). Therefore, we have to try an alternate
1059 mechanism to find the dynamic linker's base address. */
1061 TRY_CATCH (ex
, RETURN_MASK_ALL
)
1063 tmp_bfd
= solib_bfd_open (buf
);
1065 if (tmp_bfd
== NULL
)
1066 goto bkpt_at_symbol
;
1068 /* Now convert the TMP_BFD into a target. That way target, as
1069 well as BFD operations can be used. Note that closing the
1070 target will also close the underlying bfd. */
1071 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
);
1073 /* On a running target, we can get the dynamic linker's base
1074 address from the shared library table. */
1075 so
= master_so_list ();
1078 if (svr4_same_1 (buf
, so
->so_original_name
))
1080 load_addr_found
= 1;
1081 loader_found_in_list
= 1;
1082 load_addr
= LM_ADDR_CHECK (so
, tmp_bfd
);
1088 /* If we were not able to find the base address of the loader
1089 from our so_list, then try using the AT_BASE auxilliary entry. */
1090 if (!load_addr_found
)
1091 if (target_auxv_search (¤t_target
, AT_BASE
, &load_addr
) > 0)
1092 load_addr_found
= 1;
1094 /* Otherwise we find the dynamic linker's base address by examining
1095 the current pc (which should point at the entry point for the
1096 dynamic linker) and subtracting the offset of the entry point.
1098 This is more fragile than the previous approaches, but is a good
1099 fallback method because it has actually been working well in
1101 if (!load_addr_found
)
1102 load_addr
= (read_pc ()
1103 - exec_entry_point (tmp_bfd
, tmp_bfd_target
));
1105 if (!loader_found_in_list
)
1107 debug_loader_name
= xstrdup (buf
);
1108 debug_loader_offset_p
= 1;
1109 debug_loader_offset
= load_addr
;
1110 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1113 /* Record the relocated start and end address of the dynamic linker
1114 text and plt section for svr4_in_dynsym_resolve_code. */
1115 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1118 interp_text_sect_low
=
1119 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1120 interp_text_sect_high
=
1121 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1123 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1126 interp_plt_sect_low
=
1127 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1128 interp_plt_sect_high
=
1129 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1132 /* Now try to set a breakpoint in the dynamic linker. */
1133 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1135 sym_addr
= bfd_lookup_symbol (tmp_bfd
, *bkpt_namep
);
1141 /* Convert 'sym_addr' from a function pointer to an address.
1142 Because we pass tmp_bfd_target instead of the current
1143 target, this will always produce an unrelocated value. */
1144 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1148 /* We're done with both the temporary bfd and target. Remember,
1149 closing the target closes the underlying bfd. */
1150 target_close (tmp_bfd_target
, 0);
1154 create_solib_event_breakpoint (load_addr
+ sym_addr
);
1158 /* For whatever reason we couldn't set a breakpoint in the dynamic
1159 linker. Warn and drop into the old code. */
1161 warning (_("Unable to find dynamic linker breakpoint function.\n"
1162 "GDB will be unable to debug shared library initializers\n"
1163 "and track explicitly loaded dynamic code."));
1166 /* Scan through the lists of symbols, trying to look up the symbol and
1167 set a breakpoint there. Terminate loop when we/if we succeed. */
1169 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1171 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1172 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1174 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1179 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1181 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1182 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1184 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1195 special_symbol_handling -- additional shared library symbol handling
1199 void special_symbol_handling ()
1203 Once the symbols from a shared object have been loaded in the usual
1204 way, we are called to do any system specific symbol handling that
1207 For SunOS4, this consisted of grunging around in the dynamic
1208 linkers structures to find symbol definitions for "common" symbols
1209 and adding them to the minimal symbol table for the runtime common
1212 However, for SVR4, there's nothing to do.
1217 svr4_special_symbol_handling (void)
1221 /* Relocate the main executable. This function should be called upon
1222 stopping the inferior process at the entry point to the program.
1223 The entry point from BFD is compared to the PC and if they are
1224 different, the main executable is relocated by the proper amount.
1226 As written it will only attempt to relocate executables which
1227 lack interpreter sections. It seems likely that only dynamic
1228 linker executables will get relocated, though it should work
1229 properly for a position-independent static executable as well. */
1232 svr4_relocate_main_executable (void)
1234 asection
*interp_sect
;
1235 CORE_ADDR pc
= read_pc ();
1237 /* Decide if the objfile needs to be relocated. As indicated above,
1238 we will only be here when execution is stopped at the beginning
1239 of the program. Relocation is necessary if the address at which
1240 we are presently stopped differs from the start address stored in
1241 the executable AND there's no interpreter section. The condition
1242 regarding the interpreter section is very important because if
1243 there *is* an interpreter section, execution will begin there
1244 instead. When there is an interpreter section, the start address
1245 is (presumably) used by the interpreter at some point to start
1246 execution of the program.
1248 If there is an interpreter, it is normal for it to be set to an
1249 arbitrary address at the outset. The job of finding it is
1250 handled in enable_break().
1252 So, to summarize, relocations are necessary when there is no
1253 interpreter section and the start address obtained from the
1254 executable is different from the address at which GDB is
1257 [ The astute reader will note that we also test to make sure that
1258 the executable in question has the DYNAMIC flag set. It is my
1259 opinion that this test is unnecessary (undesirable even). It
1260 was added to avoid inadvertent relocation of an executable
1261 whose e_type member in the ELF header is not ET_DYN. There may
1262 be a time in the future when it is desirable to do relocations
1263 on other types of files as well in which case this condition
1264 should either be removed or modified to accomodate the new file
1265 type. (E.g, an ET_EXEC executable which has been built to be
1266 position-independent could safely be relocated by the OS if
1267 desired. It is true that this violates the ABI, but the ABI
1268 has been known to be bent from time to time.) - Kevin, Nov 2000. ]
1271 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
1272 if (interp_sect
== NULL
1273 && (bfd_get_file_flags (exec_bfd
) & DYNAMIC
) != 0
1274 && (exec_entry_point (exec_bfd
, &exec_ops
) != pc
))
1276 struct cleanup
*old_chain
;
1277 struct section_offsets
*new_offsets
;
1279 CORE_ADDR displacement
;
1281 /* It is necessary to relocate the objfile. The amount to
1282 relocate by is simply the address at which we are stopped
1283 minus the starting address from the executable.
1285 We relocate all of the sections by the same amount. This
1286 behavior is mandated by recent editions of the System V ABI.
1287 According to the System V Application Binary Interface,
1288 Edition 4.1, page 5-5:
1290 ... Though the system chooses virtual addresses for
1291 individual processes, it maintains the segments' relative
1292 positions. Because position-independent code uses relative
1293 addressesing between segments, the difference between
1294 virtual addresses in memory must match the difference
1295 between virtual addresses in the file. The difference
1296 between the virtual address of any segment in memory and
1297 the corresponding virtual address in the file is thus a
1298 single constant value for any one executable or shared
1299 object in a given process. This difference is the base
1300 address. One use of the base address is to relocate the
1301 memory image of the program during dynamic linking.
1303 The same language also appears in Edition 4.0 of the System V
1304 ABI and is left unspecified in some of the earlier editions. */
1306 displacement
= pc
- exec_entry_point (exec_bfd
, &exec_ops
);
1309 new_offsets
= xcalloc (symfile_objfile
->num_sections
,
1310 sizeof (struct section_offsets
));
1311 old_chain
= make_cleanup (xfree
, new_offsets
);
1313 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
1315 if (displacement
!= ANOFFSET (symfile_objfile
->section_offsets
, i
))
1317 new_offsets
->offsets
[i
] = displacement
;
1321 objfile_relocate (symfile_objfile
, new_offsets
);
1323 do_cleanups (old_chain
);
1331 svr4_solib_create_inferior_hook -- shared library startup support
1335 void svr4_solib_create_inferior_hook ()
1339 When gdb starts up the inferior, it nurses it along (through the
1340 shell) until it is ready to execute it's first instruction. At this
1341 point, this function gets called via expansion of the macro
1342 SOLIB_CREATE_INFERIOR_HOOK.
1344 For SunOS executables, this first instruction is typically the
1345 one at "_start", or a similar text label, regardless of whether
1346 the executable is statically or dynamically linked. The runtime
1347 startup code takes care of dynamically linking in any shared
1348 libraries, once gdb allows the inferior to continue.
1350 For SVR4 executables, this first instruction is either the first
1351 instruction in the dynamic linker (for dynamically linked
1352 executables) or the instruction at "start" for statically linked
1353 executables. For dynamically linked executables, the system
1354 first exec's /lib/libc.so.N, which contains the dynamic linker,
1355 and starts it running. The dynamic linker maps in any needed
1356 shared libraries, maps in the actual user executable, and then
1357 jumps to "start" in the user executable.
1359 For both SunOS shared libraries, and SVR4 shared libraries, we
1360 can arrange to cooperate with the dynamic linker to discover the
1361 names of shared libraries that are dynamically linked, and the
1362 base addresses to which they are linked.
1364 This function is responsible for discovering those names and
1365 addresses, and saving sufficient information about them to allow
1366 their symbols to be read at a later time.
1370 Between enable_break() and disable_break(), this code does not
1371 properly handle hitting breakpoints which the user might have
1372 set in the startup code or in the dynamic linker itself. Proper
1373 handling will probably have to wait until the implementation is
1374 changed to use the "breakpoint handler function" method.
1376 Also, what if child has exit()ed? Must exit loop somehow.
1380 svr4_solib_create_inferior_hook (void)
1382 /* Relocate the main executable if necessary. */
1383 svr4_relocate_main_executable ();
1385 if (!svr4_have_link_map_offsets ())
1388 if (!enable_break ())
1391 #if defined(_SCO_DS)
1392 /* SCO needs the loop below, other systems should be using the
1393 special shared library breakpoints and the shared library breakpoint
1396 Now run the target. It will eventually hit the breakpoint, at
1397 which point all of the libraries will have been mapped in and we
1398 can go groveling around in the dynamic linker structures to find
1399 out what we need to know about them. */
1401 clear_proceed_status ();
1402 stop_soon
= STOP_QUIETLY
;
1403 stop_signal
= TARGET_SIGNAL_0
;
1406 target_resume (pid_to_ptid (-1), 0, stop_signal
);
1407 wait_for_inferior (0);
1409 while (stop_signal
!= TARGET_SIGNAL_TRAP
);
1410 stop_soon
= NO_STOP_QUIETLY
;
1411 #endif /* defined(_SCO_DS) */
1415 svr4_clear_solib (void)
1418 debug_loader_offset_p
= 0;
1419 debug_loader_offset
= 0;
1420 xfree (debug_loader_name
);
1421 debug_loader_name
= NULL
;
1426 svr4_free_so (struct so_list
*so
)
1428 xfree (so
->lm_info
->lm
);
1429 xfree (so
->lm_info
);
1433 /* Clear any bits of ADDR that wouldn't fit in a target-format
1434 data pointer. "Data pointer" here refers to whatever sort of
1435 address the dynamic linker uses to manage its sections. At the
1436 moment, we don't support shared libraries on any processors where
1437 code and data pointers are different sizes.
1439 This isn't really the right solution. What we really need here is
1440 a way to do arithmetic on CORE_ADDR values that respects the
1441 natural pointer/address correspondence. (For example, on the MIPS,
1442 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
1443 sign-extend the value. There, simply truncating the bits above
1444 gdbarch_ptr_bit, as we do below, is no good.) This should probably
1445 be a new gdbarch method or something. */
1447 svr4_truncate_ptr (CORE_ADDR addr
)
1449 if (gdbarch_ptr_bit (target_gdbarch
) == sizeof (CORE_ADDR
) * 8)
1450 /* We don't need to truncate anything, and the bit twiddling below
1451 will fail due to overflow problems. */
1454 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch
)) - 1);
1459 svr4_relocate_section_addresses (struct so_list
*so
,
1460 struct section_table
*sec
)
1462 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ LM_ADDR_CHECK (so
,
1464 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ LM_ADDR_CHECK (so
,
1469 /* Architecture-specific operations. */
1471 /* Per-architecture data key. */
1472 static struct gdbarch_data
*solib_svr4_data
;
1474 struct solib_svr4_ops
1476 /* Return a description of the layout of `struct link_map'. */
1477 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
1480 /* Return a default for the architecture-specific operations. */
1483 solib_svr4_init (struct obstack
*obstack
)
1485 struct solib_svr4_ops
*ops
;
1487 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
1488 ops
->fetch_link_map_offsets
= NULL
;
1492 /* Set the architecture-specific `struct link_map_offsets' fetcher for
1493 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
1496 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
1497 struct link_map_offsets
*(*flmo
) (void))
1499 struct solib_svr4_ops
*ops
= gdbarch_data (gdbarch
, solib_svr4_data
);
1501 ops
->fetch_link_map_offsets
= flmo
;
1503 set_solib_ops (gdbarch
, &svr4_so_ops
);
1506 /* Fetch a link_map_offsets structure using the architecture-specific
1507 `struct link_map_offsets' fetcher. */
1509 static struct link_map_offsets
*
1510 svr4_fetch_link_map_offsets (void)
1512 struct solib_svr4_ops
*ops
= gdbarch_data (target_gdbarch
, solib_svr4_data
);
1514 gdb_assert (ops
->fetch_link_map_offsets
);
1515 return ops
->fetch_link_map_offsets ();
1518 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
1521 svr4_have_link_map_offsets (void)
1523 struct solib_svr4_ops
*ops
= gdbarch_data (target_gdbarch
, solib_svr4_data
);
1524 return (ops
->fetch_link_map_offsets
!= NULL
);
1528 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
1529 `struct r_debug' and a `struct link_map' that are binary compatible
1530 with the origional SVR4 implementation. */
1532 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1533 for an ILP32 SVR4 system. */
1535 struct link_map_offsets
*
1536 svr4_ilp32_fetch_link_map_offsets (void)
1538 static struct link_map_offsets lmo
;
1539 static struct link_map_offsets
*lmp
= NULL
;
1545 lmo
.r_version_offset
= 0;
1546 lmo
.r_version_size
= 4;
1547 lmo
.r_map_offset
= 4;
1548 lmo
.r_brk_offset
= 8;
1549 lmo
.r_ldsomap_offset
= 20;
1551 /* Everything we need is in the first 20 bytes. */
1552 lmo
.link_map_size
= 20;
1553 lmo
.l_addr_offset
= 0;
1554 lmo
.l_name_offset
= 4;
1555 lmo
.l_ld_offset
= 8;
1556 lmo
.l_next_offset
= 12;
1557 lmo
.l_prev_offset
= 16;
1563 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1564 for an LP64 SVR4 system. */
1566 struct link_map_offsets
*
1567 svr4_lp64_fetch_link_map_offsets (void)
1569 static struct link_map_offsets lmo
;
1570 static struct link_map_offsets
*lmp
= NULL
;
1576 lmo
.r_version_offset
= 0;
1577 lmo
.r_version_size
= 4;
1578 lmo
.r_map_offset
= 8;
1579 lmo
.r_brk_offset
= 16;
1580 lmo
.r_ldsomap_offset
= 40;
1582 /* Everything we need is in the first 40 bytes. */
1583 lmo
.link_map_size
= 40;
1584 lmo
.l_addr_offset
= 0;
1585 lmo
.l_name_offset
= 8;
1586 lmo
.l_ld_offset
= 16;
1587 lmo
.l_next_offset
= 24;
1588 lmo
.l_prev_offset
= 32;
1595 struct target_so_ops svr4_so_ops
;
1597 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
1598 different rule for symbol lookup. The lookup begins here in the DSO, not in
1599 the main executable. */
1601 static struct symbol
*
1602 elf_lookup_lib_symbol (const struct objfile
*objfile
,
1604 const char *linkage_name
,
1605 const domain_enum domain
)
1607 if (objfile
->obfd
== NULL
1608 || scan_dyntag (DT_SYMBOLIC
, objfile
->obfd
, NULL
) != 1)
1611 return lookup_global_symbol_from_objfile
1612 (objfile
, name
, linkage_name
, domain
);
1615 extern initialize_file_ftype _initialize_svr4_solib
; /* -Wmissing-prototypes */
1618 _initialize_svr4_solib (void)
1620 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
1622 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
1623 svr4_so_ops
.free_so
= svr4_free_so
;
1624 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
1625 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
1626 svr4_so_ops
.special_symbol_handling
= svr4_special_symbol_handling
;
1627 svr4_so_ops
.current_sos
= svr4_current_sos
;
1628 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
1629 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
1630 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
1631 svr4_so_ops
.same
= svr4_same
;