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"
46 static struct link_map_offsets
*svr4_fetch_link_map_offsets (void);
47 static int svr4_have_link_map_offsets (void);
49 /* Link map info to include in an allocated so_list entry */
53 /* Pointer to copy of link map from inferior. The type is char *
54 rather than void *, so that we may use byte offsets to find the
55 various fields without the need for a cast. */
58 /* Amount by which addresses in the binary should be relocated to
59 match the inferior. This could most often be taken directly
60 from lm, but when prelinking is involved and the prelink base
61 address changes, we may need a different offset, we want to
62 warn about the difference and compute it only once. */
66 /* On SVR4 systems, a list of symbols in the dynamic linker where
67 GDB can try to place a breakpoint to monitor shared library
70 If none of these symbols are found, or other errors occur, then
71 SVR4 systems will fall back to using a symbol as the "startup
72 mapping complete" breakpoint address. */
74 static char *solib_break_names
[] =
85 #define BKPT_AT_SYMBOL 1
87 #if defined (BKPT_AT_SYMBOL)
88 static char *bkpt_names
[] =
90 #ifdef SOLIB_BKPT_NAME
91 SOLIB_BKPT_NAME
, /* Prefer configured name if it exists. */
100 static char *main_name_list
[] =
106 /* link map access functions */
109 LM_ADDR_FROM_LINK_MAP (struct so_list
*so
)
111 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
113 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_addr_offset
,
114 builtin_type_void_data_ptr
);
118 HAS_LM_DYNAMIC_FROM_LINK_MAP ()
120 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
122 return lmo
->l_ld_offset
>= 0;
126 LM_DYNAMIC_FROM_LINK_MAP (struct so_list
*so
)
128 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
130 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_ld_offset
,
131 builtin_type_void_data_ptr
);
135 LM_ADDR_CHECK (struct so_list
*so
, bfd
*abfd
)
137 if (so
->lm_info
->l_addr
== (CORE_ADDR
)-1)
139 struct bfd_section
*dyninfo_sect
;
140 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
, align
= 0x1000;
142 l_addr
= LM_ADDR_FROM_LINK_MAP (so
);
144 if (! abfd
|| ! HAS_LM_DYNAMIC_FROM_LINK_MAP ())
147 l_dynaddr
= LM_DYNAMIC_FROM_LINK_MAP (so
);
149 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
150 if (dyninfo_sect
== NULL
)
153 dynaddr
= bfd_section_vma (abfd
, dyninfo_sect
);
155 if (dynaddr
+ l_addr
!= l_dynaddr
)
157 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
159 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
160 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
165 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
166 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
167 align
= phdr
[i
].p_align
;
170 /* Turn it into a mask. */
173 /* If the changes match the alignment requirements, we
174 assume we're using a core file that was generated by the
175 same binary, just prelinked with a different base offset.
176 If it doesn't match, we may have a different binary, the
177 same binary with the dynamic table loaded at an unrelated
178 location, or anything, really. To avoid regressions,
179 don't adjust the base offset in the latter case, although
180 odds are that, if things really changed, debugging won't
182 if ((l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
184 l_addr
= l_dynaddr
- dynaddr
;
186 warning (_(".dynamic section for \"%s\" "
187 "is not at the expected address"), so
->so_name
);
188 warning (_("difference appears to be caused by prelink, "
189 "adjusting expectations"));
192 warning (_(".dynamic section for \"%s\" "
193 "is not at the expected address "
194 "(wrong library or version mismatch?)"), so
->so_name
);
198 so
->lm_info
->l_addr
= l_addr
;
201 return so
->lm_info
->l_addr
;
205 LM_NEXT (struct so_list
*so
)
207 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
209 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_next_offset
,
210 builtin_type_void_data_ptr
);
214 LM_NAME (struct so_list
*so
)
216 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
218 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_name_offset
,
219 builtin_type_void_data_ptr
);
223 IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list
*so
)
225 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
227 /* Assume that everything is a library if the dynamic loader was loaded
228 late by a static executable. */
229 if (bfd_get_section_by_name (exec_bfd
, ".dynamic") == NULL
)
232 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_prev_offset
,
233 builtin_type_void_data_ptr
) == 0;
236 static CORE_ADDR debug_base
; /* Base of dynamic linker structures */
238 /* Validity flag for debug_loader_offset. */
239 static int debug_loader_offset_p
;
241 /* Load address for the dynamic linker, inferred. */
242 static CORE_ADDR debug_loader_offset
;
244 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
245 static char *debug_loader_name
;
247 /* Local function prototypes */
249 static int match_main (char *);
251 static CORE_ADDR
bfd_lookup_symbol (bfd
*, char *);
257 bfd_lookup_symbol -- lookup the value for a specific symbol
261 CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
265 An expensive way to lookup the value of a single symbol for
266 bfd's that are only temporary anyway. This is used by the
267 shared library support to find the address of the debugger
268 notification routine in the shared library.
270 The returned symbol may be in a code or data section; functions
271 will normally be in a code section, but may be in a data section
272 if this architecture uses function descriptors.
274 Note that 0 is specifically allowed as an error return (no
279 bfd_lookup_symbol (bfd
*abfd
, char *symname
)
283 asymbol
**symbol_table
;
284 unsigned int number_of_symbols
;
286 struct cleanup
*back_to
;
287 CORE_ADDR symaddr
= 0;
289 storage_needed
= bfd_get_symtab_upper_bound (abfd
);
291 if (storage_needed
> 0)
293 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
294 back_to
= make_cleanup (xfree
, symbol_table
);
295 number_of_symbols
= bfd_canonicalize_symtab (abfd
, symbol_table
);
297 for (i
= 0; i
< number_of_symbols
; i
++)
299 sym
= *symbol_table
++;
300 if (strcmp (sym
->name
, symname
) == 0
301 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0)
303 /* BFD symbols are section relative. */
304 symaddr
= sym
->value
+ sym
->section
->vma
;
308 do_cleanups (back_to
);
314 /* On FreeBSD, the dynamic linker is stripped by default. So we'll
315 have to check the dynamic string table too. */
317 storage_needed
= bfd_get_dynamic_symtab_upper_bound (abfd
);
319 if (storage_needed
> 0)
321 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
322 back_to
= make_cleanup (xfree
, symbol_table
);
323 number_of_symbols
= bfd_canonicalize_dynamic_symtab (abfd
, symbol_table
);
325 for (i
= 0; i
< number_of_symbols
; i
++)
327 sym
= *symbol_table
++;
329 if (strcmp (sym
->name
, symname
) == 0
330 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0)
332 /* BFD symbols are section relative. */
333 symaddr
= sym
->value
+ sym
->section
->vma
;
337 do_cleanups (back_to
);
343 /* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is
344 returned and the corresponding PTR is set. */
347 scan_dyntag (int dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
)
349 int arch_size
, step
, sect_size
;
351 CORE_ADDR dyn_ptr
, dyn_addr
;
352 gdb_byte
*bufend
, *bufstart
, *buf
;
353 Elf32_External_Dyn
*x_dynp_32
;
354 Elf64_External_Dyn
*x_dynp_64
;
355 struct bfd_section
*sect
;
359 arch_size
= bfd_get_arch_size (abfd
);
363 /* Find the start address of the .dynamic section. */
364 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
367 dyn_addr
= bfd_section_vma (abfd
, sect
);
369 /* Read in .dynamic from the BFD. We will get the actual value
370 from memory later. */
371 sect_size
= bfd_section_size (abfd
, sect
);
372 buf
= bufstart
= alloca (sect_size
);
373 if (!bfd_get_section_contents (abfd
, sect
,
377 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
378 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
379 : sizeof (Elf64_External_Dyn
);
380 for (bufend
= buf
+ sect_size
;
386 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
387 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
388 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
392 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
393 dyn_tag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
394 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
396 if (dyn_tag
== DT_NULL
)
398 if (dyn_tag
== dyntag
)
400 /* If requested, try to read the runtime value of this .dynamic
407 ptr_addr
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
408 if (target_read_memory (ptr_addr
, ptr_buf
, arch_size
/ 8) == 0)
409 dyn_ptr
= extract_typed_address (ptr_buf
,
410 builtin_type_void_data_ptr
);
425 elf_locate_base -- locate the base address of dynamic linker structs
426 for SVR4 elf targets.
430 CORE_ADDR elf_locate_base (void)
434 For SVR4 elf targets the address of the dynamic linker's runtime
435 structure is contained within the dynamic info section in the
436 executable file. The dynamic section is also mapped into the
437 inferior address space. Because the runtime loader fills in the
438 real address before starting the inferior, we have to read in the
439 dynamic info section from the inferior address space.
440 If there are any errors while trying to find the address, we
441 silently return 0, otherwise the found address is returned.
446 elf_locate_base (void)
448 struct minimal_symbol
*msymbol
;
451 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
452 instead of DT_DEBUG, although they sometimes contain an unused
454 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
))
457 int pbuf_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
458 pbuf
= alloca (pbuf_size
);
459 /* DT_MIPS_RLD_MAP contains a pointer to the address
460 of the dynamic link structure. */
461 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
463 return extract_typed_address (pbuf
, builtin_type_void_data_ptr
);
467 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
))
470 /* This may be a static executable. Look for the symbol
471 conventionally named _r_debug, as a last resort. */
472 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
474 return SYMBOL_VALUE_ADDRESS (msymbol
);
476 /* DT_DEBUG entry not found. */
484 locate_base -- locate the base address of dynamic linker structs
488 CORE_ADDR locate_base (void)
492 For both the SunOS and SVR4 shared library implementations, if the
493 inferior executable has been linked dynamically, there is a single
494 address somewhere in the inferior's data space which is the key to
495 locating all of the dynamic linker's runtime structures. This
496 address is the value of the debug base symbol. The job of this
497 function is to find and return that address, or to return 0 if there
498 is no such address (the executable is statically linked for example).
500 For SunOS, the job is almost trivial, since the dynamic linker and
501 all of it's structures are statically linked to the executable at
502 link time. Thus the symbol for the address we are looking for has
503 already been added to the minimal symbol table for the executable's
504 objfile at the time the symbol file's symbols were read, and all we
505 have to do is look it up there. Note that we explicitly do NOT want
506 to find the copies in the shared library.
508 The SVR4 version is a bit more complicated because the address
509 is contained somewhere in the dynamic info section. We have to go
510 to a lot more work to discover the address of the debug base symbol.
511 Because of this complexity, we cache the value we find and return that
512 value on subsequent invocations. Note there is no copy in the
513 executable symbol tables.
520 /* Check to see if we have a currently valid address, and if so, avoid
521 doing all this work again and just return the cached address. If
522 we have no cached address, try to locate it in the dynamic info
523 section for ELF executables. There's no point in doing any of this
524 though if we don't have some link map offsets to work with. */
526 if (debug_base
== 0 && svr4_have_link_map_offsets ())
529 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
530 debug_base
= elf_locate_base ();
535 /* Find the first element in the inferior's dynamic link map, and
536 return its address in the inferior.
538 FIXME: Perhaps we should validate the info somehow, perhaps by
539 checking r_version for a known version number, or r_state for
543 solib_svr4_r_map (void)
545 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
547 return read_memory_typed_address (debug_base
+ lmo
->r_map_offset
,
548 builtin_type_void_data_ptr
);
551 /* Find r_brk from the inferior's debug base. */
554 solib_svr4_r_brk (void)
556 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
558 return read_memory_typed_address (debug_base
+ lmo
->r_brk_offset
,
559 builtin_type_void_data_ptr
);
562 /* Find the link map for the dynamic linker (if it is not in the
563 normal list of loaded shared objects). */
566 solib_svr4_r_ldsomap (void)
568 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
571 /* Check version, and return zero if `struct r_debug' doesn't have
572 the r_ldsomap member. */
573 version
= read_memory_unsigned_integer (debug_base
+ lmo
->r_version_offset
,
574 lmo
->r_version_size
);
575 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
578 return read_memory_typed_address (debug_base
+ lmo
->r_ldsomap_offset
,
579 builtin_type_void_data_ptr
);
586 open_symbol_file_object
590 void open_symbol_file_object (void *from_tty)
594 If no open symbol file, attempt to locate and open the main symbol
595 file. On SVR4 systems, this is the first link map entry. If its
596 name is here, we can open it. Useful when attaching to a process
597 without first loading its symbol file.
599 If FROM_TTYP dereferences to a non-zero integer, allow messages to
600 be printed. This parameter is a pointer rather than an int because
601 open_symbol_file_object() is called via catch_errors() and
602 catch_errors() requires a pointer argument. */
605 open_symbol_file_object (void *from_ttyp
)
607 CORE_ADDR lm
, l_name
;
610 int from_tty
= *(int *)from_ttyp
;
611 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
612 int l_name_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
613 gdb_byte
*l_name_buf
= xmalloc (l_name_size
);
614 struct cleanup
*cleanups
= make_cleanup (xfree
, l_name_buf
);
617 if (!query ("Attempt to reload symbols from process? "))
620 /* Always locate the debug struct, in case it has moved. */
622 if (locate_base () == 0)
623 return 0; /* failed somehow... */
625 /* First link map member should be the executable. */
626 lm
= solib_svr4_r_map ();
628 return 0; /* failed somehow... */
630 /* Read address of name from target memory to GDB. */
631 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
633 /* Convert the address to host format. */
634 l_name
= extract_typed_address (l_name_buf
, builtin_type_void_data_ptr
);
636 /* Free l_name_buf. */
637 do_cleanups (cleanups
);
640 return 0; /* No filename. */
642 /* Now fetch the filename from target memory. */
643 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
644 make_cleanup (xfree
, filename
);
648 warning (_("failed to read exec filename from attached file: %s"),
649 safe_strerror (errcode
));
653 /* Have a pathname: read the symbol file. */
654 symbol_file_add_main (filename
, from_tty
);
659 /* If no shared library information is available from the dynamic
660 linker, build a fallback list from other sources. */
662 static struct so_list
*
663 svr4_default_sos (void)
665 struct so_list
*head
= NULL
;
666 struct so_list
**link_ptr
= &head
;
668 if (debug_loader_offset_p
)
670 struct so_list
*new = XZALLOC (struct so_list
);
672 new->lm_info
= xmalloc (sizeof (struct lm_info
));
674 /* Nothing will ever check the cached copy of the link
675 map if we set l_addr. */
676 new->lm_info
->l_addr
= debug_loader_offset
;
677 new->lm_info
->lm
= NULL
;
679 strncpy (new->so_name
, debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
680 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
681 strcpy (new->so_original_name
, new->so_name
);
684 link_ptr
= &new->next
;
692 current_sos -- build a list of currently loaded shared objects
696 struct so_list *current_sos ()
700 Build a list of `struct so_list' objects describing the shared
701 objects currently loaded in the inferior. This list does not
702 include an entry for the main executable file.
704 Note that we only gather information directly available from the
705 inferior --- we don't examine any of the shared library files
706 themselves. The declaration of `struct so_list' says which fields
707 we provide values for. */
709 static struct so_list
*
710 svr4_current_sos (void)
713 struct so_list
*head
= 0;
714 struct so_list
**link_ptr
= &head
;
715 CORE_ADDR ldsomap
= 0;
717 /* Always locate the debug struct, in case it has moved. */
721 /* If we can't find the dynamic linker's base structure, this
722 must not be a dynamically linked executable. Hmm. */
724 return svr4_default_sos ();
726 /* Walk the inferior's link map list, and build our list of
727 `struct so_list' nodes. */
728 lm
= solib_svr4_r_map ();
732 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
733 struct so_list
*new = XZALLOC (struct so_list
);
734 struct cleanup
*old_chain
= make_cleanup (xfree
, new);
736 new->lm_info
= xmalloc (sizeof (struct lm_info
));
737 make_cleanup (xfree
, new->lm_info
);
739 new->lm_info
->l_addr
= (CORE_ADDR
)-1;
740 new->lm_info
->lm
= xzalloc (lmo
->link_map_size
);
741 make_cleanup (xfree
, new->lm_info
->lm
);
743 read_memory (lm
, new->lm_info
->lm
, lmo
->link_map_size
);
747 /* For SVR4 versions, the first entry in the link map is for the
748 inferior executable, so we must ignore it. For some versions of
749 SVR4, it has no name. For others (Solaris 2.3 for example), it
750 does have a name, so we can no longer use a missing name to
751 decide when to ignore it. */
752 if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap
== 0)
759 /* Extract this shared object's name. */
760 target_read_string (LM_NAME (new), &buffer
,
761 SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
763 warning (_("Can't read pathname for load map: %s."),
764 safe_strerror (errcode
));
767 strncpy (new->so_name
, buffer
, SO_NAME_MAX_PATH_SIZE
- 1);
768 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
769 strcpy (new->so_original_name
, new->so_name
);
773 /* If this entry has no name, or its name matches the name
774 for the main executable, don't include it in the list. */
775 if (! new->so_name
[0]
776 || match_main (new->so_name
))
782 link_ptr
= &new->next
;
786 /* On Solaris, the dynamic linker is not in the normal list of
787 shared objects, so make sure we pick it up too. Having
788 symbol information for the dynamic linker is quite crucial
789 for skipping dynamic linker resolver code. */
790 if (lm
== 0 && ldsomap
== 0)
791 lm
= ldsomap
= solib_svr4_r_ldsomap ();
793 discard_cleanups (old_chain
);
797 return svr4_default_sos ();
802 /* Get the address of the link_map for a given OBJFILE. Loop through
803 the link maps, and return the address of the one corresponding to
804 the given objfile. Note that this function takes into account that
805 objfile can be the main executable, not just a shared library. The
806 main executable has always an empty name field in the linkmap. */
809 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
813 if (locate_base () == 0)
814 return 0; /* failed somehow... */
816 /* Position ourselves on the first link map. */
817 lm
= solib_svr4_r_map ();
820 /* Get info on the layout of the r_debug and link_map structures. */
821 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
824 struct lm_info objfile_lm_info
;
825 struct cleanup
*old_chain
;
826 CORE_ADDR name_address
;
827 int l_name_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
828 gdb_byte
*l_name_buf
= xmalloc (l_name_size
);
829 old_chain
= make_cleanup (xfree
, l_name_buf
);
831 /* Set up the buffer to contain the portion of the link_map
832 structure that gdb cares about. Note that this is not the
833 whole link_map structure. */
834 objfile_lm_info
.lm
= xzalloc (lmo
->link_map_size
);
835 make_cleanup (xfree
, objfile_lm_info
.lm
);
837 /* Read the link map into our internal structure. */
838 read_memory (lm
, objfile_lm_info
.lm
, lmo
->link_map_size
);
840 /* Read address of name from target memory to GDB. */
841 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
843 /* Extract this object's name. */
844 name_address
= extract_typed_address (l_name_buf
,
845 builtin_type_void_data_ptr
);
846 target_read_string (name_address
, &buffer
,
847 SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
848 make_cleanup (xfree
, buffer
);
850 warning (_("Can't read pathname for load map: %s."),
851 safe_strerror (errcode
));
854 /* Is this the linkmap for the file we want? */
855 /* If the file is not a shared library and has no name,
856 we are sure it is the main executable, so we return that. */
859 && ((strcmp (buffer
, objfile
->name
) == 0)
860 || (!(objfile
->flags
& OBJF_SHARED
)
861 && (strcmp (buffer
, "") == 0))))
863 do_cleanups (old_chain
);
867 /* Not the file we wanted, continue checking. */
868 lm
= extract_typed_address (objfile_lm_info
.lm
+ lmo
->l_next_offset
,
869 builtin_type_void_data_ptr
);
870 do_cleanups (old_chain
);
875 /* On some systems, the only way to recognize the link map entry for
876 the main executable file is by looking at its name. Return
877 non-zero iff SONAME matches one of the known main executable names. */
880 match_main (char *soname
)
884 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
886 if (strcmp (soname
, *mainp
) == 0)
893 /* Return 1 if PC lies in the dynamic symbol resolution code of the
894 SVR4 run time loader. */
895 static CORE_ADDR interp_text_sect_low
;
896 static CORE_ADDR interp_text_sect_high
;
897 static CORE_ADDR interp_plt_sect_low
;
898 static CORE_ADDR interp_plt_sect_high
;
901 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
903 return ((pc
>= interp_text_sect_low
&& pc
< interp_text_sect_high
)
904 || (pc
>= interp_plt_sect_low
&& pc
< interp_plt_sect_high
)
905 || in_plt_section (pc
, NULL
));
908 /* Given an executable's ABFD and target, compute the entry-point
912 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
914 /* KevinB wrote ... for most targets, the address returned by
915 bfd_get_start_address() is the entry point for the start
916 function. But, for some targets, bfd_get_start_address() returns
917 the address of a function descriptor from which the entry point
918 address may be extracted. This address is extracted by
919 gdbarch_convert_from_func_ptr_addr(). The method
920 gdbarch_convert_from_func_ptr_addr() is the merely the identify
921 function for targets which don't use function descriptors. */
922 return gdbarch_convert_from_func_ptr_addr (current_gdbarch
,
923 bfd_get_start_address (abfd
),
931 enable_break -- arrange for dynamic linker to hit breakpoint
935 int enable_break (void)
939 Both the SunOS and the SVR4 dynamic linkers have, as part of their
940 debugger interface, support for arranging for the inferior to hit
941 a breakpoint after mapping in the shared libraries. This function
942 enables that breakpoint.
944 For SunOS, there is a special flag location (in_debugger) which we
945 set to 1. When the dynamic linker sees this flag set, it will set
946 a breakpoint at a location known only to itself, after saving the
947 original contents of that place and the breakpoint address itself,
948 in it's own internal structures. When we resume the inferior, it
949 will eventually take a SIGTRAP when it runs into the breakpoint.
950 We handle this (in a different place) by restoring the contents of
951 the breakpointed location (which is only known after it stops),
952 chasing around to locate the shared libraries that have been
953 loaded, then resuming.
955 For SVR4, the debugger interface structure contains a member (r_brk)
956 which is statically initialized at the time the shared library is
957 built, to the offset of a function (_r_debug_state) which is guaran-
958 teed to be called once before mapping in a library, and again when
959 the mapping is complete. At the time we are examining this member,
960 it contains only the unrelocated offset of the function, so we have
961 to do our own relocation. Later, when the dynamic linker actually
962 runs, it relocates r_brk to be the actual address of _r_debug_state().
964 The debugger interface structure also contains an enumeration which
965 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
966 depending upon whether or not the library is being mapped or unmapped,
967 and then set to RT_CONSISTENT after the library is mapped/unmapped.
973 #ifdef BKPT_AT_SYMBOL
975 struct minimal_symbol
*msymbol
;
977 asection
*interp_sect
;
980 /* First, remove all the solib event breakpoints. Their addresses
981 may have changed since the last time we ran the program. */
982 remove_solib_event_breakpoints ();
984 interp_text_sect_low
= interp_text_sect_high
= 0;
985 interp_plt_sect_low
= interp_plt_sect_high
= 0;
987 /* If we already have a shared library list in the target, and
988 r_debug contains r_brk, set the breakpoint there - this should
989 mean r_brk has already been relocated. Assume the dynamic linker
990 is the object containing r_brk. */
992 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
994 if (debug_base
&& solib_svr4_r_map () != 0)
995 sym_addr
= solib_svr4_r_brk ();
999 struct obj_section
*os
;
1001 sym_addr
= gdbarch_addr_bits_remove
1002 (current_gdbarch
, gdbarch_convert_from_func_ptr_addr (current_gdbarch
,
1006 os
= find_pc_section (sym_addr
);
1009 /* Record the relocated start and end address of the dynamic linker
1010 text and plt section for svr4_in_dynsym_resolve_code. */
1012 CORE_ADDR load_addr
;
1014 tmp_bfd
= os
->objfile
->obfd
;
1015 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
1016 os
->objfile
->sect_index_text
);
1018 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1021 interp_text_sect_low
=
1022 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1023 interp_text_sect_high
=
1024 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1026 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1029 interp_plt_sect_low
=
1030 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1031 interp_plt_sect_high
=
1032 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1035 create_solib_event_breakpoint (sym_addr
);
1040 /* Find the .interp section; if not found, warn the user and drop
1041 into the old breakpoint at symbol code. */
1042 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
1045 unsigned int interp_sect_size
;
1047 CORE_ADDR load_addr
= 0;
1048 int load_addr_found
= 0;
1049 int loader_found_in_list
= 0;
1051 bfd
*tmp_bfd
= NULL
;
1052 struct target_ops
*tmp_bfd_target
;
1054 char *tmp_pathname
= NULL
;
1056 /* Read the contents of the .interp section into a local buffer;
1057 the contents specify the dynamic linker this program uses. */
1059 interp_sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
1060 buf
= alloca (interp_sect_size
);
1061 bfd_get_section_contents (exec_bfd
, interp_sect
,
1062 buf
, 0, interp_sect_size
);
1064 /* Now we need to figure out where the dynamic linker was
1065 loaded so that we can load its symbols and place a breakpoint
1066 in the dynamic linker itself.
1068 This address is stored on the stack. However, I've been unable
1069 to find any magic formula to find it for Solaris (appears to
1070 be trivial on GNU/Linux). Therefore, we have to try an alternate
1071 mechanism to find the dynamic linker's base address. */
1073 tmp_fd
= solib_open (buf
, &tmp_pathname
);
1075 tmp_bfd
= bfd_fopen (tmp_pathname
, gnutarget
, FOPEN_RB
, tmp_fd
);
1077 if (tmp_bfd
== NULL
)
1078 goto bkpt_at_symbol
;
1080 /* Make sure the dynamic linker's really a useful object. */
1081 if (!bfd_check_format (tmp_bfd
, bfd_object
))
1083 warning (_("Unable to grok dynamic linker %s as an object file"), buf
);
1084 bfd_close (tmp_bfd
);
1085 goto bkpt_at_symbol
;
1088 /* Now convert the TMP_BFD into a target. That way target, as
1089 well as BFD operations can be used. Note that closing the
1090 target will also close the underlying bfd. */
1091 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
);
1093 /* On a running target, we can get the dynamic linker's base
1094 address from the shared library table. */
1095 so
= master_so_list ();
1098 if (strcmp (buf
, so
->so_original_name
) == 0)
1100 load_addr_found
= 1;
1101 loader_found_in_list
= 1;
1102 load_addr
= LM_ADDR_CHECK (so
, tmp_bfd
);
1108 /* If we were not able to find the base address of the loader
1109 from our so_list, then try using the AT_BASE auxilliary entry. */
1110 if (!load_addr_found
)
1111 if (target_auxv_search (¤t_target
, AT_BASE
, &load_addr
) > 0)
1112 load_addr_found
= 1;
1114 /* Otherwise we find the dynamic linker's base address by examining
1115 the current pc (which should point at the entry point for the
1116 dynamic linker) and subtracting the offset of the entry point.
1118 This is more fragile than the previous approaches, but is a good
1119 fallback method because it has actually been working well in
1121 if (!load_addr_found
)
1122 load_addr
= (read_pc ()
1123 - exec_entry_point (tmp_bfd
, tmp_bfd_target
));
1125 if (!loader_found_in_list
)
1127 debug_loader_name
= xstrdup (buf
);
1128 debug_loader_offset_p
= 1;
1129 debug_loader_offset
= load_addr
;
1130 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1133 /* Record the relocated start and end address of the dynamic linker
1134 text and plt section for svr4_in_dynsym_resolve_code. */
1135 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1138 interp_text_sect_low
=
1139 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1140 interp_text_sect_high
=
1141 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1143 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1146 interp_plt_sect_low
=
1147 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1148 interp_plt_sect_high
=
1149 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1152 /* Now try to set a breakpoint in the dynamic linker. */
1153 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1155 sym_addr
= bfd_lookup_symbol (tmp_bfd
, *bkpt_namep
);
1161 /* Convert 'sym_addr' from a function pointer to an address.
1162 Because we pass tmp_bfd_target instead of the current
1163 target, this will always produce an unrelocated value. */
1164 sym_addr
= gdbarch_convert_from_func_ptr_addr (current_gdbarch
,
1168 /* We're done with both the temporary bfd and target. Remember,
1169 closing the target closes the underlying bfd. */
1170 target_close (tmp_bfd_target
, 0);
1174 create_solib_event_breakpoint (load_addr
+ sym_addr
);
1178 /* For whatever reason we couldn't set a breakpoint in the dynamic
1179 linker. Warn and drop into the old code. */
1181 xfree (tmp_pathname
);
1182 warning (_("Unable to find dynamic linker breakpoint function.\n"
1183 "GDB will be unable to debug shared library initializers\n"
1184 "and track explicitly loaded dynamic code."));
1187 /* Scan through the lists of symbols, trying to look up the symbol and
1188 set a breakpoint there. Terminate loop when we/if we succeed. */
1190 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1192 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1193 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1195 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1200 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1202 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1203 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1205 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1209 #endif /* BKPT_AT_SYMBOL */
1218 special_symbol_handling -- additional shared library symbol handling
1222 void special_symbol_handling ()
1226 Once the symbols from a shared object have been loaded in the usual
1227 way, we are called to do any system specific symbol handling that
1230 For SunOS4, this consisted of grunging around in the dynamic
1231 linkers structures to find symbol definitions for "common" symbols
1232 and adding them to the minimal symbol table for the runtime common
1235 However, for SVR4, there's nothing to do.
1240 svr4_special_symbol_handling (void)
1244 /* Relocate the main executable. This function should be called upon
1245 stopping the inferior process at the entry point to the program.
1246 The entry point from BFD is compared to the PC and if they are
1247 different, the main executable is relocated by the proper amount.
1249 As written it will only attempt to relocate executables which
1250 lack interpreter sections. It seems likely that only dynamic
1251 linker executables will get relocated, though it should work
1252 properly for a position-independent static executable as well. */
1255 svr4_relocate_main_executable (void)
1257 asection
*interp_sect
;
1258 CORE_ADDR pc
= read_pc ();
1260 /* Decide if the objfile needs to be relocated. As indicated above,
1261 we will only be here when execution is stopped at the beginning
1262 of the program. Relocation is necessary if the address at which
1263 we are presently stopped differs from the start address stored in
1264 the executable AND there's no interpreter section. The condition
1265 regarding the interpreter section is very important because if
1266 there *is* an interpreter section, execution will begin there
1267 instead. When there is an interpreter section, the start address
1268 is (presumably) used by the interpreter at some point to start
1269 execution of the program.
1271 If there is an interpreter, it is normal for it to be set to an
1272 arbitrary address at the outset. The job of finding it is
1273 handled in enable_break().
1275 So, to summarize, relocations are necessary when there is no
1276 interpreter section and the start address obtained from the
1277 executable is different from the address at which GDB is
1280 [ The astute reader will note that we also test to make sure that
1281 the executable in question has the DYNAMIC flag set. It is my
1282 opinion that this test is unnecessary (undesirable even). It
1283 was added to avoid inadvertent relocation of an executable
1284 whose e_type member in the ELF header is not ET_DYN. There may
1285 be a time in the future when it is desirable to do relocations
1286 on other types of files as well in which case this condition
1287 should either be removed or modified to accomodate the new file
1288 type. (E.g, an ET_EXEC executable which has been built to be
1289 position-independent could safely be relocated by the OS if
1290 desired. It is true that this violates the ABI, but the ABI
1291 has been known to be bent from time to time.) - Kevin, Nov 2000. ]
1294 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
1295 if (interp_sect
== NULL
1296 && (bfd_get_file_flags (exec_bfd
) & DYNAMIC
) != 0
1297 && (exec_entry_point (exec_bfd
, &exec_ops
) != pc
))
1299 struct cleanup
*old_chain
;
1300 struct section_offsets
*new_offsets
;
1302 CORE_ADDR displacement
;
1304 /* It is necessary to relocate the objfile. The amount to
1305 relocate by is simply the address at which we are stopped
1306 minus the starting address from the executable.
1308 We relocate all of the sections by the same amount. This
1309 behavior is mandated by recent editions of the System V ABI.
1310 According to the System V Application Binary Interface,
1311 Edition 4.1, page 5-5:
1313 ... Though the system chooses virtual addresses for
1314 individual processes, it maintains the segments' relative
1315 positions. Because position-independent code uses relative
1316 addressesing between segments, the difference between
1317 virtual addresses in memory must match the difference
1318 between virtual addresses in the file. The difference
1319 between the virtual address of any segment in memory and
1320 the corresponding virtual address in the file is thus a
1321 single constant value for any one executable or shared
1322 object in a given process. This difference is the base
1323 address. One use of the base address is to relocate the
1324 memory image of the program during dynamic linking.
1326 The same language also appears in Edition 4.0 of the System V
1327 ABI and is left unspecified in some of the earlier editions. */
1329 displacement
= pc
- exec_entry_point (exec_bfd
, &exec_ops
);
1332 new_offsets
= xcalloc (symfile_objfile
->num_sections
,
1333 sizeof (struct section_offsets
));
1334 old_chain
= make_cleanup (xfree
, new_offsets
);
1336 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
1338 if (displacement
!= ANOFFSET (symfile_objfile
->section_offsets
, i
))
1340 new_offsets
->offsets
[i
] = displacement
;
1344 objfile_relocate (symfile_objfile
, new_offsets
);
1346 do_cleanups (old_chain
);
1354 svr4_solib_create_inferior_hook -- shared library startup support
1358 void svr4_solib_create_inferior_hook ()
1362 When gdb starts up the inferior, it nurses it along (through the
1363 shell) until it is ready to execute it's first instruction. At this
1364 point, this function gets called via expansion of the macro
1365 SOLIB_CREATE_INFERIOR_HOOK.
1367 For SunOS executables, this first instruction is typically the
1368 one at "_start", or a similar text label, regardless of whether
1369 the executable is statically or dynamically linked. The runtime
1370 startup code takes care of dynamically linking in any shared
1371 libraries, once gdb allows the inferior to continue.
1373 For SVR4 executables, this first instruction is either the first
1374 instruction in the dynamic linker (for dynamically linked
1375 executables) or the instruction at "start" for statically linked
1376 executables. For dynamically linked executables, the system
1377 first exec's /lib/libc.so.N, which contains the dynamic linker,
1378 and starts it running. The dynamic linker maps in any needed
1379 shared libraries, maps in the actual user executable, and then
1380 jumps to "start" in the user executable.
1382 For both SunOS shared libraries, and SVR4 shared libraries, we
1383 can arrange to cooperate with the dynamic linker to discover the
1384 names of shared libraries that are dynamically linked, and the
1385 base addresses to which they are linked.
1387 This function is responsible for discovering those names and
1388 addresses, and saving sufficient information about them to allow
1389 their symbols to be read at a later time.
1393 Between enable_break() and disable_break(), this code does not
1394 properly handle hitting breakpoints which the user might have
1395 set in the startup code or in the dynamic linker itself. Proper
1396 handling will probably have to wait until the implementation is
1397 changed to use the "breakpoint handler function" method.
1399 Also, what if child has exit()ed? Must exit loop somehow.
1403 svr4_solib_create_inferior_hook (void)
1405 /* Relocate the main executable if necessary. */
1406 svr4_relocate_main_executable ();
1408 if (!svr4_have_link_map_offsets ())
1411 if (!enable_break ())
1414 #if defined(_SCO_DS)
1415 /* SCO needs the loop below, other systems should be using the
1416 special shared library breakpoints and the shared library breakpoint
1419 Now run the target. It will eventually hit the breakpoint, at
1420 which point all of the libraries will have been mapped in and we
1421 can go groveling around in the dynamic linker structures to find
1422 out what we need to know about them. */
1424 clear_proceed_status ();
1425 stop_soon
= STOP_QUIETLY
;
1426 stop_signal
= TARGET_SIGNAL_0
;
1429 target_resume (pid_to_ptid (-1), 0, stop_signal
);
1430 wait_for_inferior (0);
1432 while (stop_signal
!= TARGET_SIGNAL_TRAP
);
1433 stop_soon
= NO_STOP_QUIETLY
;
1434 #endif /* defined(_SCO_DS) */
1438 svr4_clear_solib (void)
1441 debug_loader_offset_p
= 0;
1442 debug_loader_offset
= 0;
1443 xfree (debug_loader_name
);
1444 debug_loader_name
= NULL
;
1448 svr4_free_so (struct so_list
*so
)
1450 xfree (so
->lm_info
->lm
);
1451 xfree (so
->lm_info
);
1455 /* Clear any bits of ADDR that wouldn't fit in a target-format
1456 data pointer. "Data pointer" here refers to whatever sort of
1457 address the dynamic linker uses to manage its sections. At the
1458 moment, we don't support shared libraries on any processors where
1459 code and data pointers are different sizes.
1461 This isn't really the right solution. What we really need here is
1462 a way to do arithmetic on CORE_ADDR values that respects the
1463 natural pointer/address correspondence. (For example, on the MIPS,
1464 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
1465 sign-extend the value. There, simply truncating the bits above
1466 gdbarch_ptr_bit, as we do below, is no good.) This should probably
1467 be a new gdbarch method or something. */
1469 svr4_truncate_ptr (CORE_ADDR addr
)
1471 if (gdbarch_ptr_bit (current_gdbarch
) == sizeof (CORE_ADDR
) * 8)
1472 /* We don't need to truncate anything, and the bit twiddling below
1473 will fail due to overflow problems. */
1476 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (current_gdbarch
)) - 1);
1481 svr4_relocate_section_addresses (struct so_list
*so
,
1482 struct section_table
*sec
)
1484 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ LM_ADDR_CHECK (so
,
1486 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ LM_ADDR_CHECK (so
,
1491 /* Architecture-specific operations. */
1493 /* Per-architecture data key. */
1494 static struct gdbarch_data
*solib_svr4_data
;
1496 struct solib_svr4_ops
1498 /* Return a description of the layout of `struct link_map'. */
1499 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
1502 /* Return a default for the architecture-specific operations. */
1505 solib_svr4_init (struct obstack
*obstack
)
1507 struct solib_svr4_ops
*ops
;
1509 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
1510 ops
->fetch_link_map_offsets
= NULL
;
1514 /* Set the architecture-specific `struct link_map_offsets' fetcher for
1515 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
1518 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
1519 struct link_map_offsets
*(*flmo
) (void))
1521 struct solib_svr4_ops
*ops
= gdbarch_data (gdbarch
, solib_svr4_data
);
1523 ops
->fetch_link_map_offsets
= flmo
;
1525 set_solib_ops (gdbarch
, &svr4_so_ops
);
1528 /* Fetch a link_map_offsets structure using the architecture-specific
1529 `struct link_map_offsets' fetcher. */
1531 static struct link_map_offsets
*
1532 svr4_fetch_link_map_offsets (void)
1534 struct solib_svr4_ops
*ops
= gdbarch_data (current_gdbarch
, solib_svr4_data
);
1536 gdb_assert (ops
->fetch_link_map_offsets
);
1537 return ops
->fetch_link_map_offsets ();
1540 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
1543 svr4_have_link_map_offsets (void)
1545 struct solib_svr4_ops
*ops
= gdbarch_data (current_gdbarch
, solib_svr4_data
);
1546 return (ops
->fetch_link_map_offsets
!= NULL
);
1550 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
1551 `struct r_debug' and a `struct link_map' that are binary compatible
1552 with the origional SVR4 implementation. */
1554 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1555 for an ILP32 SVR4 system. */
1557 struct link_map_offsets
*
1558 svr4_ilp32_fetch_link_map_offsets (void)
1560 static struct link_map_offsets lmo
;
1561 static struct link_map_offsets
*lmp
= NULL
;
1567 lmo
.r_version_offset
= 0;
1568 lmo
.r_version_size
= 4;
1569 lmo
.r_map_offset
= 4;
1570 lmo
.r_brk_offset
= 8;
1571 lmo
.r_ldsomap_offset
= 20;
1573 /* Everything we need is in the first 20 bytes. */
1574 lmo
.link_map_size
= 20;
1575 lmo
.l_addr_offset
= 0;
1576 lmo
.l_name_offset
= 4;
1577 lmo
.l_ld_offset
= 8;
1578 lmo
.l_next_offset
= 12;
1579 lmo
.l_prev_offset
= 16;
1585 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1586 for an LP64 SVR4 system. */
1588 struct link_map_offsets
*
1589 svr4_lp64_fetch_link_map_offsets (void)
1591 static struct link_map_offsets lmo
;
1592 static struct link_map_offsets
*lmp
= NULL
;
1598 lmo
.r_version_offset
= 0;
1599 lmo
.r_version_size
= 4;
1600 lmo
.r_map_offset
= 8;
1601 lmo
.r_brk_offset
= 16;
1602 lmo
.r_ldsomap_offset
= 40;
1604 /* Everything we need is in the first 40 bytes. */
1605 lmo
.link_map_size
= 40;
1606 lmo
.l_addr_offset
= 0;
1607 lmo
.l_name_offset
= 8;
1608 lmo
.l_ld_offset
= 16;
1609 lmo
.l_next_offset
= 24;
1610 lmo
.l_prev_offset
= 32;
1617 struct target_so_ops svr4_so_ops
;
1619 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
1620 different rule for symbol lookup. The lookup begins here in the DSO, not in
1621 the main executable. */
1623 static struct symbol
*
1624 elf_lookup_lib_symbol (const struct objfile
*objfile
,
1626 const char *linkage_name
,
1627 const domain_enum domain
, struct symtab
**symtab
)
1629 if (objfile
->obfd
== NULL
1630 || scan_dyntag (DT_SYMBOLIC
, objfile
->obfd
, NULL
) != 1)
1633 return lookup_global_symbol_from_objfile
1634 (objfile
, name
, linkage_name
, domain
, symtab
);
1638 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
1640 if (! strcmp (gdb
->so_original_name
, inferior
->so_original_name
))
1643 /* On Solaris, when starting inferior we think that dynamic linker is
1644 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
1645 contains /lib/ld.so.1. Sometimes one file is a link to another, but
1646 sometimes they have identical content, but are not linked to each
1647 other. We don't restrict this check for Solaris, but the chances
1648 of running into this situation elsewhere are very low. */
1649 if (strcmp (gdb
->so_original_name
, "/usr/lib/ld.so.1") == 0
1650 && strcmp (inferior
->so_original_name
, "/lib/ld.so.1") == 0)
1656 extern initialize_file_ftype _initialize_svr4_solib
; /* -Wmissing-prototypes */
1659 _initialize_svr4_solib (void)
1661 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
1663 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
1664 svr4_so_ops
.free_so
= svr4_free_so
;
1665 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
1666 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
1667 svr4_so_ops
.special_symbol_handling
= svr4_special_symbol_handling
;
1668 svr4_so_ops
.current_sos
= svr4_current_sos
;
1669 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
1670 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
1671 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
1672 svr4_so_ops
.same
= svr4_same
;