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
);
378 /* Read program header TYPE from inferior memory. The header is found
379 by scanning the OS auxillary vector.
381 Return a pointer to allocated memory holding the program header contents,
382 or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the
383 size of those contents is returned to P_SECT_SIZE. Likewise, the target
384 architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE. */
387 read_program_header (int type
, int *p_sect_size
, int *p_arch_size
)
389 CORE_ADDR at_phdr
, at_phent
, at_phnum
;
390 int arch_size
, sect_size
;
394 /* Get required auxv elements from target. */
395 if (target_auxv_search (¤t_target
, AT_PHDR
, &at_phdr
) <= 0)
397 if (target_auxv_search (¤t_target
, AT_PHENT
, &at_phent
) <= 0)
399 if (target_auxv_search (¤t_target
, AT_PHNUM
, &at_phnum
) <= 0)
401 if (!at_phdr
|| !at_phnum
)
404 /* Determine ELF architecture type. */
405 if (at_phent
== sizeof (Elf32_External_Phdr
))
407 else if (at_phent
== sizeof (Elf64_External_Phdr
))
412 /* Find .dynamic section via the PT_DYNAMIC PHDR. */
415 Elf32_External_Phdr phdr
;
418 /* Search for requested PHDR. */
419 for (i
= 0; i
< at_phnum
; i
++)
421 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
422 (gdb_byte
*)&phdr
, sizeof (phdr
)))
425 if (extract_unsigned_integer ((gdb_byte
*)phdr
.p_type
, 4) == type
)
432 /* Retrieve address and size. */
433 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
, 4);
434 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
, 4);
438 Elf64_External_Phdr phdr
;
441 /* Search for requested PHDR. */
442 for (i
= 0; i
< at_phnum
; i
++)
444 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
445 (gdb_byte
*)&phdr
, sizeof (phdr
)))
448 if (extract_unsigned_integer ((gdb_byte
*)phdr
.p_type
, 4) == type
)
455 /* Retrieve address and size. */
456 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
, 8);
457 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
, 8);
460 /* Read in requested program header. */
461 buf
= xmalloc (sect_size
);
462 if (target_read_memory (sect_addr
, buf
, sect_size
))
469 *p_arch_size
= arch_size
;
471 *p_sect_size
= sect_size
;
477 /* Return program interpreter string. */
479 find_program_interpreter (void)
481 gdb_byte
*buf
= NULL
;
483 /* If we have an exec_bfd, use its section table. */
485 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
487 struct bfd_section
*interp_sect
;
489 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
490 if (interp_sect
!= NULL
)
492 CORE_ADDR sect_addr
= bfd_section_vma (exec_bfd
, interp_sect
);
493 int sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
495 buf
= xmalloc (sect_size
);
496 bfd_get_section_contents (exec_bfd
, interp_sect
, buf
, 0, sect_size
);
500 /* If we didn't find it, use the target auxillary vector. */
502 buf
= read_program_header (PT_INTERP
, NULL
, NULL
);
508 /* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is
509 returned and the corresponding PTR is set. */
512 scan_dyntag (int dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
)
514 int arch_size
, step
, sect_size
;
516 CORE_ADDR dyn_ptr
, dyn_addr
;
517 gdb_byte
*bufend
, *bufstart
, *buf
;
518 Elf32_External_Dyn
*x_dynp_32
;
519 Elf64_External_Dyn
*x_dynp_64
;
520 struct bfd_section
*sect
;
524 arch_size
= bfd_get_arch_size (abfd
);
528 /* Find the start address of the .dynamic section. */
529 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
532 dyn_addr
= bfd_section_vma (abfd
, sect
);
534 /* Read in .dynamic from the BFD. We will get the actual value
535 from memory later. */
536 sect_size
= bfd_section_size (abfd
, sect
);
537 buf
= bufstart
= alloca (sect_size
);
538 if (!bfd_get_section_contents (abfd
, sect
,
542 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
543 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
544 : sizeof (Elf64_External_Dyn
);
545 for (bufend
= buf
+ sect_size
;
551 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
552 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
553 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
557 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
558 dyn_tag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
559 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
561 if (dyn_tag
== DT_NULL
)
563 if (dyn_tag
== dyntag
)
565 /* If requested, try to read the runtime value of this .dynamic
572 ptr_addr
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
573 if (target_read_memory (ptr_addr
, ptr_buf
, arch_size
/ 8) == 0)
574 dyn_ptr
= extract_typed_address (ptr_buf
,
575 builtin_type_void_data_ptr
);
585 /* Scan for DYNTAG in .dynamic section of the target's main executable,
586 found by consulting the OS auxillary vector. If DYNTAG is found 1 is
587 returned and the corresponding PTR is set. */
590 scan_dyntag_auxv (int dyntag
, CORE_ADDR
*ptr
)
592 int sect_size
, arch_size
, step
;
595 gdb_byte
*bufend
, *bufstart
, *buf
;
597 /* Read in .dynamic section. */
598 buf
= bufstart
= read_program_header (PT_DYNAMIC
, §_size
, &arch_size
);
602 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
603 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
604 : sizeof (Elf64_External_Dyn
);
605 for (bufend
= buf
+ sect_size
;
611 Elf32_External_Dyn
*dynp
= (Elf32_External_Dyn
*) buf
;
612 dyn_tag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
, 4);
613 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
, 4);
617 Elf64_External_Dyn
*dynp
= (Elf64_External_Dyn
*) buf
;
618 dyn_tag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
, 8);
619 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
, 8);
621 if (dyn_tag
== DT_NULL
)
624 if (dyn_tag
== dyntag
)
643 elf_locate_base -- locate the base address of dynamic linker structs
644 for SVR4 elf targets.
648 CORE_ADDR elf_locate_base (void)
652 For SVR4 elf targets the address of the dynamic linker's runtime
653 structure is contained within the dynamic info section in the
654 executable file. The dynamic section is also mapped into the
655 inferior address space. Because the runtime loader fills in the
656 real address before starting the inferior, we have to read in the
657 dynamic info section from the inferior address space.
658 If there are any errors while trying to find the address, we
659 silently return 0, otherwise the found address is returned.
664 elf_locate_base (void)
666 struct minimal_symbol
*msymbol
;
669 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
670 instead of DT_DEBUG, although they sometimes contain an unused
672 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
)
673 || scan_dyntag_auxv (DT_MIPS_RLD_MAP
, &dyn_ptr
))
676 int pbuf_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
677 pbuf
= alloca (pbuf_size
);
678 /* DT_MIPS_RLD_MAP contains a pointer to the address
679 of the dynamic link structure. */
680 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
682 return extract_typed_address (pbuf
, builtin_type_void_data_ptr
);
686 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
)
687 || scan_dyntag_auxv (DT_DEBUG
, &dyn_ptr
))
690 /* This may be a static executable. Look for the symbol
691 conventionally named _r_debug, as a last resort. */
692 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
694 return SYMBOL_VALUE_ADDRESS (msymbol
);
696 /* DT_DEBUG entry not found. */
704 locate_base -- locate the base address of dynamic linker structs
708 CORE_ADDR locate_base (void)
712 For both the SunOS and SVR4 shared library implementations, if the
713 inferior executable has been linked dynamically, there is a single
714 address somewhere in the inferior's data space which is the key to
715 locating all of the dynamic linker's runtime structures. This
716 address is the value of the debug base symbol. The job of this
717 function is to find and return that address, or to return 0 if there
718 is no such address (the executable is statically linked for example).
720 For SunOS, the job is almost trivial, since the dynamic linker and
721 all of it's structures are statically linked to the executable at
722 link time. Thus the symbol for the address we are looking for has
723 already been added to the minimal symbol table for the executable's
724 objfile at the time the symbol file's symbols were read, and all we
725 have to do is look it up there. Note that we explicitly do NOT want
726 to find the copies in the shared library.
728 The SVR4 version is a bit more complicated because the address
729 is contained somewhere in the dynamic info section. We have to go
730 to a lot more work to discover the address of the debug base symbol.
731 Because of this complexity, we cache the value we find and return that
732 value on subsequent invocations. Note there is no copy in the
733 executable symbol tables.
740 /* Check to see if we have a currently valid address, and if so, avoid
741 doing all this work again and just return the cached address. If
742 we have no cached address, try to locate it in the dynamic info
743 section for ELF executables. There's no point in doing any of this
744 though if we don't have some link map offsets to work with. */
746 if (debug_base
== 0 && svr4_have_link_map_offsets ())
749 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
750 debug_base
= elf_locate_base ();
755 /* Find the first element in the inferior's dynamic link map, and
756 return its address in the inferior.
758 FIXME: Perhaps we should validate the info somehow, perhaps by
759 checking r_version for a known version number, or r_state for
763 solib_svr4_r_map (void)
765 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
767 return read_memory_typed_address (debug_base
+ lmo
->r_map_offset
,
768 builtin_type_void_data_ptr
);
771 /* Find r_brk from the inferior's debug base. */
774 solib_svr4_r_brk (void)
776 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
778 return read_memory_typed_address (debug_base
+ lmo
->r_brk_offset
,
779 builtin_type_void_data_ptr
);
782 /* Find the link map for the dynamic linker (if it is not in the
783 normal list of loaded shared objects). */
786 solib_svr4_r_ldsomap (void)
788 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
791 /* Check version, and return zero if `struct r_debug' doesn't have
792 the r_ldsomap member. */
793 version
= read_memory_unsigned_integer (debug_base
+ lmo
->r_version_offset
,
794 lmo
->r_version_size
);
795 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
798 return read_memory_typed_address (debug_base
+ lmo
->r_ldsomap_offset
,
799 builtin_type_void_data_ptr
);
806 open_symbol_file_object
810 void open_symbol_file_object (void *from_tty)
814 If no open symbol file, attempt to locate and open the main symbol
815 file. On SVR4 systems, this is the first link map entry. If its
816 name is here, we can open it. Useful when attaching to a process
817 without first loading its symbol file.
819 If FROM_TTYP dereferences to a non-zero integer, allow messages to
820 be printed. This parameter is a pointer rather than an int because
821 open_symbol_file_object() is called via catch_errors() and
822 catch_errors() requires a pointer argument. */
825 open_symbol_file_object (void *from_ttyp
)
827 CORE_ADDR lm
, l_name
;
830 int from_tty
= *(int *)from_ttyp
;
831 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
832 int l_name_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
833 gdb_byte
*l_name_buf
= xmalloc (l_name_size
);
834 struct cleanup
*cleanups
= make_cleanup (xfree
, l_name_buf
);
837 if (!query ("Attempt to reload symbols from process? "))
840 /* Always locate the debug struct, in case it has moved. */
842 if (locate_base () == 0)
843 return 0; /* failed somehow... */
845 /* First link map member should be the executable. */
846 lm
= solib_svr4_r_map ();
848 return 0; /* failed somehow... */
850 /* Read address of name from target memory to GDB. */
851 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
853 /* Convert the address to host format. */
854 l_name
= extract_typed_address (l_name_buf
, builtin_type_void_data_ptr
);
856 /* Free l_name_buf. */
857 do_cleanups (cleanups
);
860 return 0; /* No filename. */
862 /* Now fetch the filename from target memory. */
863 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
864 make_cleanup (xfree
, filename
);
868 warning (_("failed to read exec filename from attached file: %s"),
869 safe_strerror (errcode
));
873 /* Have a pathname: read the symbol file. */
874 symbol_file_add_main (filename
, from_tty
);
879 /* If no shared library information is available from the dynamic
880 linker, build a fallback list from other sources. */
882 static struct so_list
*
883 svr4_default_sos (void)
885 struct so_list
*head
= NULL
;
886 struct so_list
**link_ptr
= &head
;
888 if (debug_loader_offset_p
)
890 struct so_list
*new = XZALLOC (struct so_list
);
892 new->lm_info
= xmalloc (sizeof (struct lm_info
));
894 /* Nothing will ever check the cached copy of the link
895 map if we set l_addr. */
896 new->lm_info
->l_addr
= debug_loader_offset
;
897 new->lm_info
->lm_addr
= 0;
898 new->lm_info
->lm
= NULL
;
900 strncpy (new->so_name
, debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
901 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
902 strcpy (new->so_original_name
, new->so_name
);
905 link_ptr
= &new->next
;
913 current_sos -- build a list of currently loaded shared objects
917 struct so_list *current_sos ()
921 Build a list of `struct so_list' objects describing the shared
922 objects currently loaded in the inferior. This list does not
923 include an entry for the main executable file.
925 Note that we only gather information directly available from the
926 inferior --- we don't examine any of the shared library files
927 themselves. The declaration of `struct so_list' says which fields
928 we provide values for. */
930 static struct so_list
*
931 svr4_current_sos (void)
934 struct so_list
*head
= 0;
935 struct so_list
**link_ptr
= &head
;
936 CORE_ADDR ldsomap
= 0;
938 /* Always locate the debug struct, in case it has moved. */
942 /* If we can't find the dynamic linker's base structure, this
943 must not be a dynamically linked executable. Hmm. */
945 return svr4_default_sos ();
947 /* Walk the inferior's link map list, and build our list of
948 `struct so_list' nodes. */
949 lm
= solib_svr4_r_map ();
953 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
954 struct so_list
*new = XZALLOC (struct so_list
);
955 struct cleanup
*old_chain
= make_cleanup (xfree
, new);
957 new->lm_info
= xmalloc (sizeof (struct lm_info
));
958 make_cleanup (xfree
, new->lm_info
);
960 new->lm_info
->l_addr
= (CORE_ADDR
)-1;
961 new->lm_info
->lm_addr
= lm
;
962 new->lm_info
->lm
= xzalloc (lmo
->link_map_size
);
963 make_cleanup (xfree
, new->lm_info
->lm
);
965 read_memory (lm
, new->lm_info
->lm
, lmo
->link_map_size
);
969 /* For SVR4 versions, the first entry in the link map is for the
970 inferior executable, so we must ignore it. For some versions of
971 SVR4, it has no name. For others (Solaris 2.3 for example), it
972 does have a name, so we can no longer use a missing name to
973 decide when to ignore it. */
974 if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap
== 0)
976 main_lm_addr
= new->lm_info
->lm_addr
;
984 /* Extract this shared object's name. */
985 target_read_string (LM_NAME (new), &buffer
,
986 SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
988 warning (_("Can't read pathname for load map: %s."),
989 safe_strerror (errcode
));
992 strncpy (new->so_name
, buffer
, SO_NAME_MAX_PATH_SIZE
- 1);
993 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
994 strcpy (new->so_original_name
, new->so_name
);
998 /* If this entry has no name, or its name matches the name
999 for the main executable, don't include it in the list. */
1000 if (! new->so_name
[0]
1001 || match_main (new->so_name
))
1007 link_ptr
= &new->next
;
1011 /* On Solaris, the dynamic linker is not in the normal list of
1012 shared objects, so make sure we pick it up too. Having
1013 symbol information for the dynamic linker is quite crucial
1014 for skipping dynamic linker resolver code. */
1015 if (lm
== 0 && ldsomap
== 0)
1016 lm
= ldsomap
= solib_svr4_r_ldsomap ();
1018 discard_cleanups (old_chain
);
1022 return svr4_default_sos ();
1027 /* Get the address of the link_map for a given OBJFILE. */
1030 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
1034 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1035 if (main_lm_addr
== 0)
1036 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1038 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1039 if (objfile
== symfile_objfile
)
1040 return main_lm_addr
;
1042 /* The other link map addresses may be found by examining the list
1043 of shared libraries. */
1044 for (so
= master_so_list (); so
; so
= so
->next
)
1045 if (so
->objfile
== objfile
)
1046 return so
->lm_info
->lm_addr
;
1052 /* On some systems, the only way to recognize the link map entry for
1053 the main executable file is by looking at its name. Return
1054 non-zero iff SONAME matches one of the known main executable names. */
1057 match_main (char *soname
)
1061 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
1063 if (strcmp (soname
, *mainp
) == 0)
1070 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1071 SVR4 run time loader. */
1072 static CORE_ADDR interp_text_sect_low
;
1073 static CORE_ADDR interp_text_sect_high
;
1074 static CORE_ADDR interp_plt_sect_low
;
1075 static CORE_ADDR interp_plt_sect_high
;
1078 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
1080 return ((pc
>= interp_text_sect_low
&& pc
< interp_text_sect_high
)
1081 || (pc
>= interp_plt_sect_low
&& pc
< interp_plt_sect_high
)
1082 || in_plt_section (pc
, NULL
));
1085 /* Given an executable's ABFD and target, compute the entry-point
1089 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
1091 /* KevinB wrote ... for most targets, the address returned by
1092 bfd_get_start_address() is the entry point for the start
1093 function. But, for some targets, bfd_get_start_address() returns
1094 the address of a function descriptor from which the entry point
1095 address may be extracted. This address is extracted by
1096 gdbarch_convert_from_func_ptr_addr(). The method
1097 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1098 function for targets which don't use function descriptors. */
1099 return gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1100 bfd_get_start_address (abfd
),
1108 enable_break -- arrange for dynamic linker to hit breakpoint
1112 int enable_break (void)
1116 Both the SunOS and the SVR4 dynamic linkers have, as part of their
1117 debugger interface, support for arranging for the inferior to hit
1118 a breakpoint after mapping in the shared libraries. This function
1119 enables that breakpoint.
1121 For SunOS, there is a special flag location (in_debugger) which we
1122 set to 1. When the dynamic linker sees this flag set, it will set
1123 a breakpoint at a location known only to itself, after saving the
1124 original contents of that place and the breakpoint address itself,
1125 in it's own internal structures. When we resume the inferior, it
1126 will eventually take a SIGTRAP when it runs into the breakpoint.
1127 We handle this (in a different place) by restoring the contents of
1128 the breakpointed location (which is only known after it stops),
1129 chasing around to locate the shared libraries that have been
1130 loaded, then resuming.
1132 For SVR4, the debugger interface structure contains a member (r_brk)
1133 which is statically initialized at the time the shared library is
1134 built, to the offset of a function (_r_debug_state) which is guaran-
1135 teed to be called once before mapping in a library, and again when
1136 the mapping is complete. At the time we are examining this member,
1137 it contains only the unrelocated offset of the function, so we have
1138 to do our own relocation. Later, when the dynamic linker actually
1139 runs, it relocates r_brk to be the actual address of _r_debug_state().
1141 The debugger interface structure also contains an enumeration which
1142 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
1143 depending upon whether or not the library is being mapped or unmapped,
1144 and then set to RT_CONSISTENT after the library is mapped/unmapped.
1150 struct minimal_symbol
*msymbol
;
1152 asection
*interp_sect
;
1153 gdb_byte
*interp_name
;
1156 /* First, remove all the solib event breakpoints. Their addresses
1157 may have changed since the last time we ran the program. */
1158 remove_solib_event_breakpoints ();
1160 interp_text_sect_low
= interp_text_sect_high
= 0;
1161 interp_plt_sect_low
= interp_plt_sect_high
= 0;
1163 /* If we already have a shared library list in the target, and
1164 r_debug contains r_brk, set the breakpoint there - this should
1165 mean r_brk has already been relocated. Assume the dynamic linker
1166 is the object containing r_brk. */
1168 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1170 if (debug_base
&& solib_svr4_r_map () != 0)
1171 sym_addr
= solib_svr4_r_brk ();
1175 struct obj_section
*os
;
1177 sym_addr
= gdbarch_addr_bits_remove
1178 (target_gdbarch
, gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1182 os
= find_pc_section (sym_addr
);
1185 /* Record the relocated start and end address of the dynamic linker
1186 text and plt section for svr4_in_dynsym_resolve_code. */
1188 CORE_ADDR load_addr
;
1190 tmp_bfd
= os
->objfile
->obfd
;
1191 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
1192 os
->objfile
->sect_index_text
);
1194 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1197 interp_text_sect_low
=
1198 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1199 interp_text_sect_high
=
1200 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1202 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1205 interp_plt_sect_low
=
1206 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1207 interp_plt_sect_high
=
1208 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1211 create_solib_event_breakpoint (sym_addr
);
1216 /* Find the program interpreter; if not found, warn the user and drop
1217 into the old breakpoint at symbol code. */
1218 interp_name
= find_program_interpreter ();
1221 CORE_ADDR load_addr
= 0;
1222 int load_addr_found
= 0;
1223 int loader_found_in_list
= 0;
1225 bfd
*tmp_bfd
= NULL
;
1226 struct target_ops
*tmp_bfd_target
;
1227 volatile struct gdb_exception ex
;
1231 /* Now we need to figure out where the dynamic linker was
1232 loaded so that we can load its symbols and place a breakpoint
1233 in the dynamic linker itself.
1235 This address is stored on the stack. However, I've been unable
1236 to find any magic formula to find it for Solaris (appears to
1237 be trivial on GNU/Linux). Therefore, we have to try an alternate
1238 mechanism to find the dynamic linker's base address. */
1240 TRY_CATCH (ex
, RETURN_MASK_ALL
)
1242 tmp_bfd
= solib_bfd_open (interp_name
);
1244 if (tmp_bfd
== NULL
)
1245 goto bkpt_at_symbol
;
1247 /* Now convert the TMP_BFD into a target. That way target, as
1248 well as BFD operations can be used. Note that closing the
1249 target will also close the underlying bfd. */
1250 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
);
1252 /* On a running target, we can get the dynamic linker's base
1253 address from the shared library table. */
1254 so
= master_so_list ();
1257 if (svr4_same_1 (interp_name
, so
->so_original_name
))
1259 load_addr_found
= 1;
1260 loader_found_in_list
= 1;
1261 load_addr
= LM_ADDR_CHECK (so
, tmp_bfd
);
1267 /* If we were not able to find the base address of the loader
1268 from our so_list, then try using the AT_BASE auxilliary entry. */
1269 if (!load_addr_found
)
1270 if (target_auxv_search (¤t_target
, AT_BASE
, &load_addr
) > 0)
1271 load_addr_found
= 1;
1273 /* Otherwise we find the dynamic linker's base address by examining
1274 the current pc (which should point at the entry point for the
1275 dynamic linker) and subtracting the offset of the entry point.
1277 This is more fragile than the previous approaches, but is a good
1278 fallback method because it has actually been working well in
1280 if (!load_addr_found
)
1281 load_addr
= (read_pc ()
1282 - exec_entry_point (tmp_bfd
, tmp_bfd_target
));
1284 if (!loader_found_in_list
)
1286 debug_loader_name
= xstrdup (interp_name
);
1287 debug_loader_offset_p
= 1;
1288 debug_loader_offset
= load_addr
;
1289 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1292 /* Record the relocated start and end address of the dynamic linker
1293 text and plt section for svr4_in_dynsym_resolve_code. */
1294 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1297 interp_text_sect_low
=
1298 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1299 interp_text_sect_high
=
1300 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1302 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1305 interp_plt_sect_low
=
1306 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1307 interp_plt_sect_high
=
1308 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1311 /* Now try to set a breakpoint in the dynamic linker. */
1312 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1314 sym_addr
= bfd_lookup_symbol (tmp_bfd
, *bkpt_namep
);
1320 /* Convert 'sym_addr' from a function pointer to an address.
1321 Because we pass tmp_bfd_target instead of the current
1322 target, this will always produce an unrelocated value. */
1323 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1327 /* We're done with both the temporary bfd and target. Remember,
1328 closing the target closes the underlying bfd. */
1329 target_close (tmp_bfd_target
, 0);
1333 create_solib_event_breakpoint (load_addr
+ sym_addr
);
1334 xfree (interp_name
);
1338 /* For whatever reason we couldn't set a breakpoint in the dynamic
1339 linker. Warn and drop into the old code. */
1341 xfree (interp_name
);
1342 warning (_("Unable to find dynamic linker breakpoint function.\n"
1343 "GDB will be unable to debug shared library initializers\n"
1344 "and track explicitly loaded dynamic code."));
1347 /* Scan through the lists of symbols, trying to look up the symbol and
1348 set a breakpoint there. Terminate loop when we/if we succeed. */
1350 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1352 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1353 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1355 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1360 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1362 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1363 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1365 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1376 special_symbol_handling -- additional shared library symbol handling
1380 void special_symbol_handling ()
1384 Once the symbols from a shared object have been loaded in the usual
1385 way, we are called to do any system specific symbol handling that
1388 For SunOS4, this consisted of grunging around in the dynamic
1389 linkers structures to find symbol definitions for "common" symbols
1390 and adding them to the minimal symbol table for the runtime common
1393 However, for SVR4, there's nothing to do.
1398 svr4_special_symbol_handling (void)
1402 /* Relocate the main executable. This function should be called upon
1403 stopping the inferior process at the entry point to the program.
1404 The entry point from BFD is compared to the PC and if they are
1405 different, the main executable is relocated by the proper amount.
1407 As written it will only attempt to relocate executables which
1408 lack interpreter sections. It seems likely that only dynamic
1409 linker executables will get relocated, though it should work
1410 properly for a position-independent static executable as well. */
1413 svr4_relocate_main_executable (void)
1415 asection
*interp_sect
;
1416 CORE_ADDR pc
= read_pc ();
1418 /* Decide if the objfile needs to be relocated. As indicated above,
1419 we will only be here when execution is stopped at the beginning
1420 of the program. Relocation is necessary if the address at which
1421 we are presently stopped differs from the start address stored in
1422 the executable AND there's no interpreter section. The condition
1423 regarding the interpreter section is very important because if
1424 there *is* an interpreter section, execution will begin there
1425 instead. When there is an interpreter section, the start address
1426 is (presumably) used by the interpreter at some point to start
1427 execution of the program.
1429 If there is an interpreter, it is normal for it to be set to an
1430 arbitrary address at the outset. The job of finding it is
1431 handled in enable_break().
1433 So, to summarize, relocations are necessary when there is no
1434 interpreter section and the start address obtained from the
1435 executable is different from the address at which GDB is
1438 [ The astute reader will note that we also test to make sure that
1439 the executable in question has the DYNAMIC flag set. It is my
1440 opinion that this test is unnecessary (undesirable even). It
1441 was added to avoid inadvertent relocation of an executable
1442 whose e_type member in the ELF header is not ET_DYN. There may
1443 be a time in the future when it is desirable to do relocations
1444 on other types of files as well in which case this condition
1445 should either be removed or modified to accomodate the new file
1446 type. (E.g, an ET_EXEC executable which has been built to be
1447 position-independent could safely be relocated by the OS if
1448 desired. It is true that this violates the ABI, but the ABI
1449 has been known to be bent from time to time.) - Kevin, Nov 2000. ]
1452 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
1453 if (interp_sect
== NULL
1454 && (bfd_get_file_flags (exec_bfd
) & DYNAMIC
) != 0
1455 && (exec_entry_point (exec_bfd
, &exec_ops
) != pc
))
1457 struct cleanup
*old_chain
;
1458 struct section_offsets
*new_offsets
;
1460 CORE_ADDR displacement
;
1462 /* It is necessary to relocate the objfile. The amount to
1463 relocate by is simply the address at which we are stopped
1464 minus the starting address from the executable.
1466 We relocate all of the sections by the same amount. This
1467 behavior is mandated by recent editions of the System V ABI.
1468 According to the System V Application Binary Interface,
1469 Edition 4.1, page 5-5:
1471 ... Though the system chooses virtual addresses for
1472 individual processes, it maintains the segments' relative
1473 positions. Because position-independent code uses relative
1474 addressesing between segments, the difference between
1475 virtual addresses in memory must match the difference
1476 between virtual addresses in the file. The difference
1477 between the virtual address of any segment in memory and
1478 the corresponding virtual address in the file is thus a
1479 single constant value for any one executable or shared
1480 object in a given process. This difference is the base
1481 address. One use of the base address is to relocate the
1482 memory image of the program during dynamic linking.
1484 The same language also appears in Edition 4.0 of the System V
1485 ABI and is left unspecified in some of the earlier editions. */
1487 displacement
= pc
- exec_entry_point (exec_bfd
, &exec_ops
);
1490 new_offsets
= xcalloc (symfile_objfile
->num_sections
,
1491 sizeof (struct section_offsets
));
1492 old_chain
= make_cleanup (xfree
, new_offsets
);
1494 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
1496 if (displacement
!= ANOFFSET (symfile_objfile
->section_offsets
, i
))
1498 new_offsets
->offsets
[i
] = displacement
;
1502 objfile_relocate (symfile_objfile
, new_offsets
);
1504 do_cleanups (old_chain
);
1512 svr4_solib_create_inferior_hook -- shared library startup support
1516 void svr4_solib_create_inferior_hook ()
1520 When gdb starts up the inferior, it nurses it along (through the
1521 shell) until it is ready to execute it's first instruction. At this
1522 point, this function gets called via expansion of the macro
1523 SOLIB_CREATE_INFERIOR_HOOK.
1525 For SunOS executables, this first instruction is typically the
1526 one at "_start", or a similar text label, regardless of whether
1527 the executable is statically or dynamically linked. The runtime
1528 startup code takes care of dynamically linking in any shared
1529 libraries, once gdb allows the inferior to continue.
1531 For SVR4 executables, this first instruction is either the first
1532 instruction in the dynamic linker (for dynamically linked
1533 executables) or the instruction at "start" for statically linked
1534 executables. For dynamically linked executables, the system
1535 first exec's /lib/libc.so.N, which contains the dynamic linker,
1536 and starts it running. The dynamic linker maps in any needed
1537 shared libraries, maps in the actual user executable, and then
1538 jumps to "start" in the user executable.
1540 For both SunOS shared libraries, and SVR4 shared libraries, we
1541 can arrange to cooperate with the dynamic linker to discover the
1542 names of shared libraries that are dynamically linked, and the
1543 base addresses to which they are linked.
1545 This function is responsible for discovering those names and
1546 addresses, and saving sufficient information about them to allow
1547 their symbols to be read at a later time.
1551 Between enable_break() and disable_break(), this code does not
1552 properly handle hitting breakpoints which the user might have
1553 set in the startup code or in the dynamic linker itself. Proper
1554 handling will probably have to wait until the implementation is
1555 changed to use the "breakpoint handler function" method.
1557 Also, what if child has exit()ed? Must exit loop somehow.
1561 svr4_solib_create_inferior_hook (void)
1563 /* Relocate the main executable if necessary. */
1564 svr4_relocate_main_executable ();
1566 if (!svr4_have_link_map_offsets ())
1569 if (!enable_break ())
1572 #if defined(_SCO_DS)
1573 /* SCO needs the loop below, other systems should be using the
1574 special shared library breakpoints and the shared library breakpoint
1577 Now run the target. It will eventually hit the breakpoint, at
1578 which point all of the libraries will have been mapped in and we
1579 can go groveling around in the dynamic linker structures to find
1580 out what we need to know about them. */
1582 clear_proceed_status ();
1583 stop_soon
= STOP_QUIETLY
;
1584 stop_signal
= TARGET_SIGNAL_0
;
1587 target_resume (pid_to_ptid (-1), 0, stop_signal
);
1588 wait_for_inferior (0);
1590 while (stop_signal
!= TARGET_SIGNAL_TRAP
);
1591 stop_soon
= NO_STOP_QUIETLY
;
1592 #endif /* defined(_SCO_DS) */
1596 svr4_clear_solib (void)
1599 debug_loader_offset_p
= 0;
1600 debug_loader_offset
= 0;
1601 xfree (debug_loader_name
);
1602 debug_loader_name
= NULL
;
1607 svr4_free_so (struct so_list
*so
)
1609 xfree (so
->lm_info
->lm
);
1610 xfree (so
->lm_info
);
1614 /* Clear any bits of ADDR that wouldn't fit in a target-format
1615 data pointer. "Data pointer" here refers to whatever sort of
1616 address the dynamic linker uses to manage its sections. At the
1617 moment, we don't support shared libraries on any processors where
1618 code and data pointers are different sizes.
1620 This isn't really the right solution. What we really need here is
1621 a way to do arithmetic on CORE_ADDR values that respects the
1622 natural pointer/address correspondence. (For example, on the MIPS,
1623 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
1624 sign-extend the value. There, simply truncating the bits above
1625 gdbarch_ptr_bit, as we do below, is no good.) This should probably
1626 be a new gdbarch method or something. */
1628 svr4_truncate_ptr (CORE_ADDR addr
)
1630 if (gdbarch_ptr_bit (target_gdbarch
) == sizeof (CORE_ADDR
) * 8)
1631 /* We don't need to truncate anything, and the bit twiddling below
1632 will fail due to overflow problems. */
1635 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch
)) - 1);
1640 svr4_relocate_section_addresses (struct so_list
*so
,
1641 struct section_table
*sec
)
1643 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ LM_ADDR_CHECK (so
,
1645 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ LM_ADDR_CHECK (so
,
1650 /* Architecture-specific operations. */
1652 /* Per-architecture data key. */
1653 static struct gdbarch_data
*solib_svr4_data
;
1655 struct solib_svr4_ops
1657 /* Return a description of the layout of `struct link_map'. */
1658 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
1661 /* Return a default for the architecture-specific operations. */
1664 solib_svr4_init (struct obstack
*obstack
)
1666 struct solib_svr4_ops
*ops
;
1668 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
1669 ops
->fetch_link_map_offsets
= NULL
;
1673 /* Set the architecture-specific `struct link_map_offsets' fetcher for
1674 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
1677 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
1678 struct link_map_offsets
*(*flmo
) (void))
1680 struct solib_svr4_ops
*ops
= gdbarch_data (gdbarch
, solib_svr4_data
);
1682 ops
->fetch_link_map_offsets
= flmo
;
1684 set_solib_ops (gdbarch
, &svr4_so_ops
);
1687 /* Fetch a link_map_offsets structure using the architecture-specific
1688 `struct link_map_offsets' fetcher. */
1690 static struct link_map_offsets
*
1691 svr4_fetch_link_map_offsets (void)
1693 struct solib_svr4_ops
*ops
= gdbarch_data (target_gdbarch
, solib_svr4_data
);
1695 gdb_assert (ops
->fetch_link_map_offsets
);
1696 return ops
->fetch_link_map_offsets ();
1699 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
1702 svr4_have_link_map_offsets (void)
1704 struct solib_svr4_ops
*ops
= gdbarch_data (target_gdbarch
, solib_svr4_data
);
1705 return (ops
->fetch_link_map_offsets
!= NULL
);
1709 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
1710 `struct r_debug' and a `struct link_map' that are binary compatible
1711 with the origional SVR4 implementation. */
1713 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1714 for an ILP32 SVR4 system. */
1716 struct link_map_offsets
*
1717 svr4_ilp32_fetch_link_map_offsets (void)
1719 static struct link_map_offsets lmo
;
1720 static struct link_map_offsets
*lmp
= NULL
;
1726 lmo
.r_version_offset
= 0;
1727 lmo
.r_version_size
= 4;
1728 lmo
.r_map_offset
= 4;
1729 lmo
.r_brk_offset
= 8;
1730 lmo
.r_ldsomap_offset
= 20;
1732 /* Everything we need is in the first 20 bytes. */
1733 lmo
.link_map_size
= 20;
1734 lmo
.l_addr_offset
= 0;
1735 lmo
.l_name_offset
= 4;
1736 lmo
.l_ld_offset
= 8;
1737 lmo
.l_next_offset
= 12;
1738 lmo
.l_prev_offset
= 16;
1744 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1745 for an LP64 SVR4 system. */
1747 struct link_map_offsets
*
1748 svr4_lp64_fetch_link_map_offsets (void)
1750 static struct link_map_offsets lmo
;
1751 static struct link_map_offsets
*lmp
= NULL
;
1757 lmo
.r_version_offset
= 0;
1758 lmo
.r_version_size
= 4;
1759 lmo
.r_map_offset
= 8;
1760 lmo
.r_brk_offset
= 16;
1761 lmo
.r_ldsomap_offset
= 40;
1763 /* Everything we need is in the first 40 bytes. */
1764 lmo
.link_map_size
= 40;
1765 lmo
.l_addr_offset
= 0;
1766 lmo
.l_name_offset
= 8;
1767 lmo
.l_ld_offset
= 16;
1768 lmo
.l_next_offset
= 24;
1769 lmo
.l_prev_offset
= 32;
1776 struct target_so_ops svr4_so_ops
;
1778 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
1779 different rule for symbol lookup. The lookup begins here in the DSO, not in
1780 the main executable. */
1782 static struct symbol
*
1783 elf_lookup_lib_symbol (const struct objfile
*objfile
,
1785 const char *linkage_name
,
1786 const domain_enum domain
)
1788 if (objfile
->obfd
== NULL
1789 || scan_dyntag (DT_SYMBOLIC
, objfile
->obfd
, NULL
) != 1)
1792 return lookup_global_symbol_from_objfile
1793 (objfile
, name
, linkage_name
, domain
);
1796 extern initialize_file_ftype _initialize_svr4_solib
; /* -Wmissing-prototypes */
1799 _initialize_svr4_solib (void)
1801 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
1803 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
1804 svr4_so_ops
.free_so
= svr4_free_so
;
1805 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
1806 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
1807 svr4_so_ops
.special_symbol_handling
= svr4_special_symbol_handling
;
1808 svr4_so_ops
.current_sos
= svr4_current_sos
;
1809 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
1810 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
1811 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
1812 svr4_so_ops
.same
= svr4_same
;