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"
34 #include "gdbthread.h"
36 #include "gdb_assert.h"
40 #include "solib-svr4.h"
42 #include "bfd-target.h"
46 #include "exceptions.h"
48 static struct link_map_offsets
*svr4_fetch_link_map_offsets (void);
49 static int svr4_have_link_map_offsets (void);
51 /* Link map info to include in an allocated so_list entry */
55 /* Pointer to copy of link map from inferior. The type is char *
56 rather than void *, so that we may use byte offsets to find the
57 various fields without the need for a cast. */
60 /* Amount by which addresses in the binary should be relocated to
61 match the inferior. This could most often be taken directly
62 from lm, but when prelinking is involved and the prelink base
63 address changes, we may need a different offset, we want to
64 warn about the difference and compute it only once. */
67 /* The target location of lm. */
71 /* On SVR4 systems, a list of symbols in the dynamic linker where
72 GDB can try to place a breakpoint to monitor shared library
75 If none of these symbols are found, or other errors occur, then
76 SVR4 systems will fall back to using a symbol as the "startup
77 mapping complete" breakpoint address. */
79 static char *solib_break_names
[] =
90 static char *bkpt_names
[] =
98 static char *main_name_list
[] =
104 /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent
105 the same shared library. */
108 svr4_same_1 (const char *gdb_so_name
, const char *inferior_so_name
)
110 if (strcmp (gdb_so_name
, inferior_so_name
) == 0)
113 /* On Solaris, when starting inferior we think that dynamic linker is
114 /usr/lib/ld.so.1, but later on, the table of loaded shared libraries
115 contains /lib/ld.so.1. Sometimes one file is a link to another, but
116 sometimes they have identical content, but are not linked to each
117 other. We don't restrict this check for Solaris, but the chances
118 of running into this situation elsewhere are very low. */
119 if (strcmp (gdb_so_name
, "/usr/lib/ld.so.1") == 0
120 && strcmp (inferior_so_name
, "/lib/ld.so.1") == 0)
123 /* Similarly, we observed the same issue with sparc64, but with
124 different locations. */
125 if (strcmp (gdb_so_name
, "/usr/lib/sparcv9/ld.so.1") == 0
126 && strcmp (inferior_so_name
, "/lib/sparcv9/ld.so.1") == 0)
133 svr4_same (struct so_list
*gdb
, struct so_list
*inferior
)
135 return (svr4_same_1 (gdb
->so_original_name
, inferior
->so_original_name
));
138 /* link map access functions */
141 LM_ADDR_FROM_LINK_MAP (struct so_list
*so
)
143 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
145 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_addr_offset
,
146 builtin_type_void_data_ptr
);
150 HAS_LM_DYNAMIC_FROM_LINK_MAP ()
152 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
154 return lmo
->l_ld_offset
>= 0;
158 LM_DYNAMIC_FROM_LINK_MAP (struct so_list
*so
)
160 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
162 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_ld_offset
,
163 builtin_type_void_data_ptr
);
167 LM_ADDR_CHECK (struct so_list
*so
, bfd
*abfd
)
169 if (so
->lm_info
->l_addr
== (CORE_ADDR
)-1)
171 struct bfd_section
*dyninfo_sect
;
172 CORE_ADDR l_addr
, l_dynaddr
, dynaddr
, align
= 0x1000;
174 l_addr
= LM_ADDR_FROM_LINK_MAP (so
);
176 if (! abfd
|| ! HAS_LM_DYNAMIC_FROM_LINK_MAP ())
179 l_dynaddr
= LM_DYNAMIC_FROM_LINK_MAP (so
);
181 dyninfo_sect
= bfd_get_section_by_name (abfd
, ".dynamic");
182 if (dyninfo_sect
== NULL
)
185 dynaddr
= bfd_section_vma (abfd
, dyninfo_sect
);
187 if (dynaddr
+ l_addr
!= l_dynaddr
)
189 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
191 Elf_Internal_Ehdr
*ehdr
= elf_tdata (abfd
)->elf_header
;
192 Elf_Internal_Phdr
*phdr
= elf_tdata (abfd
)->phdr
;
197 for (i
= 0; i
< ehdr
->e_phnum
; i
++)
198 if (phdr
[i
].p_type
== PT_LOAD
&& phdr
[i
].p_align
> align
)
199 align
= phdr
[i
].p_align
;
202 /* Turn it into a mask. */
205 /* If the changes match the alignment requirements, we
206 assume we're using a core file that was generated by the
207 same binary, just prelinked with a different base offset.
208 If it doesn't match, we may have a different binary, the
209 same binary with the dynamic table loaded at an unrelated
210 location, or anything, really. To avoid regressions,
211 don't adjust the base offset in the latter case, although
212 odds are that, if things really changed, debugging won't
214 if ((l_addr
& align
) == ((l_dynaddr
- dynaddr
) & align
))
216 l_addr
= l_dynaddr
- dynaddr
;
218 warning (_(".dynamic section for \"%s\" "
219 "is not at the expected address"), so
->so_name
);
220 warning (_("difference appears to be caused by prelink, "
221 "adjusting expectations"));
224 warning (_(".dynamic section for \"%s\" "
225 "is not at the expected address "
226 "(wrong library or version mismatch?)"), so
->so_name
);
230 so
->lm_info
->l_addr
= l_addr
;
233 return so
->lm_info
->l_addr
;
237 LM_NEXT (struct so_list
*so
)
239 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
241 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_next_offset
,
242 builtin_type_void_data_ptr
);
246 LM_NAME (struct so_list
*so
)
248 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
250 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_name_offset
,
251 builtin_type_void_data_ptr
);
255 IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list
*so
)
257 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
259 /* Assume that everything is a library if the dynamic loader was loaded
260 late by a static executable. */
261 if (bfd_get_section_by_name (exec_bfd
, ".dynamic") == NULL
)
264 return extract_typed_address (so
->lm_info
->lm
+ lmo
->l_prev_offset
,
265 builtin_type_void_data_ptr
) == 0;
268 static CORE_ADDR debug_base
; /* Base of dynamic linker structures */
270 /* Validity flag for debug_loader_offset. */
271 static int debug_loader_offset_p
;
273 /* Load address for the dynamic linker, inferred. */
274 static CORE_ADDR debug_loader_offset
;
276 /* Name of the dynamic linker, valid if debug_loader_offset_p. */
277 static char *debug_loader_name
;
279 /* Load map address for the main executable. */
280 static CORE_ADDR main_lm_addr
;
282 /* Local function prototypes */
284 static int match_main (char *);
286 static CORE_ADDR
bfd_lookup_symbol (bfd
*, char *);
292 bfd_lookup_symbol -- lookup the value for a specific symbol
296 CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
300 An expensive way to lookup the value of a single symbol for
301 bfd's that are only temporary anyway. This is used by the
302 shared library support to find the address of the debugger
303 notification routine in the shared library.
305 The returned symbol may be in a code or data section; functions
306 will normally be in a code section, but may be in a data section
307 if this architecture uses function descriptors.
309 Note that 0 is specifically allowed as an error return (no
314 bfd_lookup_symbol (bfd
*abfd
, char *symname
)
318 asymbol
**symbol_table
;
319 unsigned int number_of_symbols
;
321 struct cleanup
*back_to
;
322 CORE_ADDR symaddr
= 0;
324 storage_needed
= bfd_get_symtab_upper_bound (abfd
);
326 if (storage_needed
> 0)
328 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
329 back_to
= make_cleanup (xfree
, symbol_table
);
330 number_of_symbols
= bfd_canonicalize_symtab (abfd
, symbol_table
);
332 for (i
= 0; i
< number_of_symbols
; i
++)
334 sym
= *symbol_table
++;
335 if (strcmp (sym
->name
, symname
) == 0
336 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0)
338 /* BFD symbols are section relative. */
339 symaddr
= sym
->value
+ sym
->section
->vma
;
343 do_cleanups (back_to
);
349 /* On FreeBSD, the dynamic linker is stripped by default. So we'll
350 have to check the dynamic string table too. */
352 storage_needed
= bfd_get_dynamic_symtab_upper_bound (abfd
);
354 if (storage_needed
> 0)
356 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
357 back_to
= make_cleanup (xfree
, symbol_table
);
358 number_of_symbols
= bfd_canonicalize_dynamic_symtab (abfd
, symbol_table
);
360 for (i
= 0; i
< number_of_symbols
; i
++)
362 sym
= *symbol_table
++;
364 if (strcmp (sym
->name
, symname
) == 0
365 && (sym
->section
->flags
& (SEC_CODE
| SEC_DATA
)) != 0)
367 /* BFD symbols are section relative. */
368 symaddr
= sym
->value
+ sym
->section
->vma
;
372 do_cleanups (back_to
);
379 /* Read program header TYPE from inferior memory. The header is found
380 by scanning the OS auxillary vector.
382 Return a pointer to allocated memory holding the program header contents,
383 or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the
384 size of those contents is returned to P_SECT_SIZE. Likewise, the target
385 architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE. */
388 read_program_header (int type
, int *p_sect_size
, int *p_arch_size
)
390 CORE_ADDR at_phdr
, at_phent
, at_phnum
;
391 int arch_size
, sect_size
;
395 /* Get required auxv elements from target. */
396 if (target_auxv_search (¤t_target
, AT_PHDR
, &at_phdr
) <= 0)
398 if (target_auxv_search (¤t_target
, AT_PHENT
, &at_phent
) <= 0)
400 if (target_auxv_search (¤t_target
, AT_PHNUM
, &at_phnum
) <= 0)
402 if (!at_phdr
|| !at_phnum
)
405 /* Determine ELF architecture type. */
406 if (at_phent
== sizeof (Elf32_External_Phdr
))
408 else if (at_phent
== sizeof (Elf64_External_Phdr
))
413 /* Find .dynamic section via the PT_DYNAMIC PHDR. */
416 Elf32_External_Phdr phdr
;
419 /* Search for requested PHDR. */
420 for (i
= 0; i
< at_phnum
; i
++)
422 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
423 (gdb_byte
*)&phdr
, sizeof (phdr
)))
426 if (extract_unsigned_integer ((gdb_byte
*)phdr
.p_type
, 4) == type
)
433 /* Retrieve address and size. */
434 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
, 4);
435 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
, 4);
439 Elf64_External_Phdr phdr
;
442 /* Search for requested PHDR. */
443 for (i
= 0; i
< at_phnum
; i
++)
445 if (target_read_memory (at_phdr
+ i
* sizeof (phdr
),
446 (gdb_byte
*)&phdr
, sizeof (phdr
)))
449 if (extract_unsigned_integer ((gdb_byte
*)phdr
.p_type
, 4) == type
)
456 /* Retrieve address and size. */
457 sect_addr
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_vaddr
, 8);
458 sect_size
= extract_unsigned_integer ((gdb_byte
*)phdr
.p_memsz
, 8);
461 /* Read in requested program header. */
462 buf
= xmalloc (sect_size
);
463 if (target_read_memory (sect_addr
, buf
, sect_size
))
470 *p_arch_size
= arch_size
;
472 *p_sect_size
= sect_size
;
478 /* Return program interpreter string. */
480 find_program_interpreter (void)
482 gdb_byte
*buf
= NULL
;
484 /* If we have an exec_bfd, use its section table. */
486 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
488 struct bfd_section
*interp_sect
;
490 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
491 if (interp_sect
!= NULL
)
493 CORE_ADDR sect_addr
= bfd_section_vma (exec_bfd
, interp_sect
);
494 int sect_size
= bfd_section_size (exec_bfd
, interp_sect
);
496 buf
= xmalloc (sect_size
);
497 bfd_get_section_contents (exec_bfd
, interp_sect
, buf
, 0, sect_size
);
501 /* If we didn't find it, use the target auxillary vector. */
503 buf
= read_program_header (PT_INTERP
, NULL
, NULL
);
509 /* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is
510 returned and the corresponding PTR is set. */
513 scan_dyntag (int dyntag
, bfd
*abfd
, CORE_ADDR
*ptr
)
515 int arch_size
, step
, sect_size
;
517 CORE_ADDR dyn_ptr
, dyn_addr
;
518 gdb_byte
*bufend
, *bufstart
, *buf
;
519 Elf32_External_Dyn
*x_dynp_32
;
520 Elf64_External_Dyn
*x_dynp_64
;
521 struct bfd_section
*sect
;
525 arch_size
= bfd_get_arch_size (abfd
);
529 /* Find the start address of the .dynamic section. */
530 sect
= bfd_get_section_by_name (abfd
, ".dynamic");
533 dyn_addr
= bfd_section_vma (abfd
, sect
);
535 /* Read in .dynamic from the BFD. We will get the actual value
536 from memory later. */
537 sect_size
= bfd_section_size (abfd
, sect
);
538 buf
= bufstart
= alloca (sect_size
);
539 if (!bfd_get_section_contents (abfd
, sect
,
543 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
544 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
545 : sizeof (Elf64_External_Dyn
);
546 for (bufend
= buf
+ sect_size
;
552 x_dynp_32
= (Elf32_External_Dyn
*) buf
;
553 dyn_tag
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_tag
);
554 dyn_ptr
= bfd_h_get_32 (abfd
, (bfd_byte
*) x_dynp_32
->d_un
.d_ptr
);
558 x_dynp_64
= (Elf64_External_Dyn
*) buf
;
559 dyn_tag
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_tag
);
560 dyn_ptr
= bfd_h_get_64 (abfd
, (bfd_byte
*) x_dynp_64
->d_un
.d_ptr
);
562 if (dyn_tag
== DT_NULL
)
564 if (dyn_tag
== dyntag
)
566 /* If requested, try to read the runtime value of this .dynamic
573 ptr_addr
= dyn_addr
+ (buf
- bufstart
) + arch_size
/ 8;
574 if (target_read_memory (ptr_addr
, ptr_buf
, arch_size
/ 8) == 0)
575 dyn_ptr
= extract_typed_address (ptr_buf
,
576 builtin_type_void_data_ptr
);
586 /* Scan for DYNTAG in .dynamic section of the target's main executable,
587 found by consulting the OS auxillary vector. If DYNTAG is found 1 is
588 returned and the corresponding PTR is set. */
591 scan_dyntag_auxv (int dyntag
, CORE_ADDR
*ptr
)
593 int sect_size
, arch_size
, step
;
596 gdb_byte
*bufend
, *bufstart
, *buf
;
598 /* Read in .dynamic section. */
599 buf
= bufstart
= read_program_header (PT_DYNAMIC
, §_size
, &arch_size
);
603 /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
604 step
= (arch_size
== 32) ? sizeof (Elf32_External_Dyn
)
605 : sizeof (Elf64_External_Dyn
);
606 for (bufend
= buf
+ sect_size
;
612 Elf32_External_Dyn
*dynp
= (Elf32_External_Dyn
*) buf
;
613 dyn_tag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
, 4);
614 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
, 4);
618 Elf64_External_Dyn
*dynp
= (Elf64_External_Dyn
*) buf
;
619 dyn_tag
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_tag
, 8);
620 dyn_ptr
= extract_unsigned_integer ((gdb_byte
*) dynp
->d_un
.d_ptr
, 8);
622 if (dyn_tag
== DT_NULL
)
625 if (dyn_tag
== dyntag
)
644 elf_locate_base -- locate the base address of dynamic linker structs
645 for SVR4 elf targets.
649 CORE_ADDR elf_locate_base (void)
653 For SVR4 elf targets the address of the dynamic linker's runtime
654 structure is contained within the dynamic info section in the
655 executable file. The dynamic section is also mapped into the
656 inferior address space. Because the runtime loader fills in the
657 real address before starting the inferior, we have to read in the
658 dynamic info section from the inferior address space.
659 If there are any errors while trying to find the address, we
660 silently return 0, otherwise the found address is returned.
665 elf_locate_base (void)
667 struct minimal_symbol
*msymbol
;
670 /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
671 instead of DT_DEBUG, although they sometimes contain an unused
673 if (scan_dyntag (DT_MIPS_RLD_MAP
, exec_bfd
, &dyn_ptr
)
674 || scan_dyntag_auxv (DT_MIPS_RLD_MAP
, &dyn_ptr
))
677 int pbuf_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
678 pbuf
= alloca (pbuf_size
);
679 /* DT_MIPS_RLD_MAP contains a pointer to the address
680 of the dynamic link structure. */
681 if (target_read_memory (dyn_ptr
, pbuf
, pbuf_size
))
683 return extract_typed_address (pbuf
, builtin_type_void_data_ptr
);
687 if (scan_dyntag (DT_DEBUG
, exec_bfd
, &dyn_ptr
)
688 || scan_dyntag_auxv (DT_DEBUG
, &dyn_ptr
))
691 /* This may be a static executable. Look for the symbol
692 conventionally named _r_debug, as a last resort. */
693 msymbol
= lookup_minimal_symbol ("_r_debug", NULL
, symfile_objfile
);
695 return SYMBOL_VALUE_ADDRESS (msymbol
);
697 /* DT_DEBUG entry not found. */
705 locate_base -- locate the base address of dynamic linker structs
709 CORE_ADDR locate_base (void)
713 For both the SunOS and SVR4 shared library implementations, if the
714 inferior executable has been linked dynamically, there is a single
715 address somewhere in the inferior's data space which is the key to
716 locating all of the dynamic linker's runtime structures. This
717 address is the value of the debug base symbol. The job of this
718 function is to find and return that address, or to return 0 if there
719 is no such address (the executable is statically linked for example).
721 For SunOS, the job is almost trivial, since the dynamic linker and
722 all of it's structures are statically linked to the executable at
723 link time. Thus the symbol for the address we are looking for has
724 already been added to the minimal symbol table for the executable's
725 objfile at the time the symbol file's symbols were read, and all we
726 have to do is look it up there. Note that we explicitly do NOT want
727 to find the copies in the shared library.
729 The SVR4 version is a bit more complicated because the address
730 is contained somewhere in the dynamic info section. We have to go
731 to a lot more work to discover the address of the debug base symbol.
732 Because of this complexity, we cache the value we find and return that
733 value on subsequent invocations. Note there is no copy in the
734 executable symbol tables.
741 /* Check to see if we have a currently valid address, and if so, avoid
742 doing all this work again and just return the cached address. If
743 we have no cached address, try to locate it in the dynamic info
744 section for ELF executables. There's no point in doing any of this
745 though if we don't have some link map offsets to work with. */
747 if (debug_base
== 0 && svr4_have_link_map_offsets ())
750 && bfd_get_flavour (exec_bfd
) == bfd_target_elf_flavour
)
751 debug_base
= elf_locate_base ();
756 /* Find the first element in the inferior's dynamic link map, and
757 return its address in the inferior.
759 FIXME: Perhaps we should validate the info somehow, perhaps by
760 checking r_version for a known version number, or r_state for
764 solib_svr4_r_map (void)
766 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
768 return read_memory_typed_address (debug_base
+ lmo
->r_map_offset
,
769 builtin_type_void_data_ptr
);
772 /* Find r_brk from the inferior's debug base. */
775 solib_svr4_r_brk (void)
777 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
779 return read_memory_typed_address (debug_base
+ lmo
->r_brk_offset
,
780 builtin_type_void_data_ptr
);
783 /* Find the link map for the dynamic linker (if it is not in the
784 normal list of loaded shared objects). */
787 solib_svr4_r_ldsomap (void)
789 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
792 /* Check version, and return zero if `struct r_debug' doesn't have
793 the r_ldsomap member. */
794 version
= read_memory_unsigned_integer (debug_base
+ lmo
->r_version_offset
,
795 lmo
->r_version_size
);
796 if (version
< 2 || lmo
->r_ldsomap_offset
== -1)
799 return read_memory_typed_address (debug_base
+ lmo
->r_ldsomap_offset
,
800 builtin_type_void_data_ptr
);
807 open_symbol_file_object
811 void open_symbol_file_object (void *from_tty)
815 If no open symbol file, attempt to locate and open the main symbol
816 file. On SVR4 systems, this is the first link map entry. If its
817 name is here, we can open it. Useful when attaching to a process
818 without first loading its symbol file.
820 If FROM_TTYP dereferences to a non-zero integer, allow messages to
821 be printed. This parameter is a pointer rather than an int because
822 open_symbol_file_object() is called via catch_errors() and
823 catch_errors() requires a pointer argument. */
826 open_symbol_file_object (void *from_ttyp
)
828 CORE_ADDR lm
, l_name
;
831 int from_tty
= *(int *)from_ttyp
;
832 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
833 int l_name_size
= TYPE_LENGTH (builtin_type_void_data_ptr
);
834 gdb_byte
*l_name_buf
= xmalloc (l_name_size
);
835 struct cleanup
*cleanups
= make_cleanup (xfree
, l_name_buf
);
838 if (!query ("Attempt to reload symbols from process? "))
841 /* Always locate the debug struct, in case it has moved. */
843 if (locate_base () == 0)
844 return 0; /* failed somehow... */
846 /* First link map member should be the executable. */
847 lm
= solib_svr4_r_map ();
849 return 0; /* failed somehow... */
851 /* Read address of name from target memory to GDB. */
852 read_memory (lm
+ lmo
->l_name_offset
, l_name_buf
, l_name_size
);
854 /* Convert the address to host format. */
855 l_name
= extract_typed_address (l_name_buf
, builtin_type_void_data_ptr
);
857 /* Free l_name_buf. */
858 do_cleanups (cleanups
);
861 return 0; /* No filename. */
863 /* Now fetch the filename from target memory. */
864 target_read_string (l_name
, &filename
, SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
865 make_cleanup (xfree
, filename
);
869 warning (_("failed to read exec filename from attached file: %s"),
870 safe_strerror (errcode
));
874 /* Have a pathname: read the symbol file. */
875 symbol_file_add_main (filename
, from_tty
);
880 /* If no shared library information is available from the dynamic
881 linker, build a fallback list from other sources. */
883 static struct so_list
*
884 svr4_default_sos (void)
886 struct so_list
*head
= NULL
;
887 struct so_list
**link_ptr
= &head
;
889 if (debug_loader_offset_p
)
891 struct so_list
*new = XZALLOC (struct so_list
);
893 new->lm_info
= xmalloc (sizeof (struct lm_info
));
895 /* Nothing will ever check the cached copy of the link
896 map if we set l_addr. */
897 new->lm_info
->l_addr
= debug_loader_offset
;
898 new->lm_info
->lm_addr
= 0;
899 new->lm_info
->lm
= NULL
;
901 strncpy (new->so_name
, debug_loader_name
, SO_NAME_MAX_PATH_SIZE
- 1);
902 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
903 strcpy (new->so_original_name
, new->so_name
);
906 link_ptr
= &new->next
;
914 current_sos -- build a list of currently loaded shared objects
918 struct so_list *current_sos ()
922 Build a list of `struct so_list' objects describing the shared
923 objects currently loaded in the inferior. This list does not
924 include an entry for the main executable file.
926 Note that we only gather information directly available from the
927 inferior --- we don't examine any of the shared library files
928 themselves. The declaration of `struct so_list' says which fields
929 we provide values for. */
931 static struct so_list
*
932 svr4_current_sos (void)
935 struct so_list
*head
= 0;
936 struct so_list
**link_ptr
= &head
;
937 CORE_ADDR ldsomap
= 0;
939 /* Always locate the debug struct, in case it has moved. */
943 /* If we can't find the dynamic linker's base structure, this
944 must not be a dynamically linked executable. Hmm. */
946 return svr4_default_sos ();
948 /* Walk the inferior's link map list, and build our list of
949 `struct so_list' nodes. */
950 lm
= solib_svr4_r_map ();
954 struct link_map_offsets
*lmo
= svr4_fetch_link_map_offsets ();
955 struct so_list
*new = XZALLOC (struct so_list
);
956 struct cleanup
*old_chain
= make_cleanup (xfree
, new);
958 new->lm_info
= xmalloc (sizeof (struct lm_info
));
959 make_cleanup (xfree
, new->lm_info
);
961 new->lm_info
->l_addr
= (CORE_ADDR
)-1;
962 new->lm_info
->lm_addr
= lm
;
963 new->lm_info
->lm
= xzalloc (lmo
->link_map_size
);
964 make_cleanup (xfree
, new->lm_info
->lm
);
966 read_memory (lm
, new->lm_info
->lm
, lmo
->link_map_size
);
970 /* For SVR4 versions, the first entry in the link map is for the
971 inferior executable, so we must ignore it. For some versions of
972 SVR4, it has no name. For others (Solaris 2.3 for example), it
973 does have a name, so we can no longer use a missing name to
974 decide when to ignore it. */
975 if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap
== 0)
977 main_lm_addr
= new->lm_info
->lm_addr
;
985 /* Extract this shared object's name. */
986 target_read_string (LM_NAME (new), &buffer
,
987 SO_NAME_MAX_PATH_SIZE
- 1, &errcode
);
989 warning (_("Can't read pathname for load map: %s."),
990 safe_strerror (errcode
));
993 strncpy (new->so_name
, buffer
, SO_NAME_MAX_PATH_SIZE
- 1);
994 new->so_name
[SO_NAME_MAX_PATH_SIZE
- 1] = '\0';
995 strcpy (new->so_original_name
, new->so_name
);
999 /* If this entry has no name, or its name matches the name
1000 for the main executable, don't include it in the list. */
1001 if (! new->so_name
[0]
1002 || match_main (new->so_name
))
1008 link_ptr
= &new->next
;
1012 /* On Solaris, the dynamic linker is not in the normal list of
1013 shared objects, so make sure we pick it up too. Having
1014 symbol information for the dynamic linker is quite crucial
1015 for skipping dynamic linker resolver code. */
1016 if (lm
== 0 && ldsomap
== 0)
1017 lm
= ldsomap
= solib_svr4_r_ldsomap ();
1019 discard_cleanups (old_chain
);
1023 return svr4_default_sos ();
1028 /* Get the address of the link_map for a given OBJFILE. */
1031 svr4_fetch_objfile_link_map (struct objfile
*objfile
)
1035 /* Cause svr4_current_sos() to be run if it hasn't been already. */
1036 if (main_lm_addr
== 0)
1037 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1039 /* svr4_current_sos() will set main_lm_addr for the main executable. */
1040 if (objfile
== symfile_objfile
)
1041 return main_lm_addr
;
1043 /* The other link map addresses may be found by examining the list
1044 of shared libraries. */
1045 for (so
= master_so_list (); so
; so
= so
->next
)
1046 if (so
->objfile
== objfile
)
1047 return so
->lm_info
->lm_addr
;
1053 /* On some systems, the only way to recognize the link map entry for
1054 the main executable file is by looking at its name. Return
1055 non-zero iff SONAME matches one of the known main executable names. */
1058 match_main (char *soname
)
1062 for (mainp
= main_name_list
; *mainp
!= NULL
; mainp
++)
1064 if (strcmp (soname
, *mainp
) == 0)
1071 /* Return 1 if PC lies in the dynamic symbol resolution code of the
1072 SVR4 run time loader. */
1073 static CORE_ADDR interp_text_sect_low
;
1074 static CORE_ADDR interp_text_sect_high
;
1075 static CORE_ADDR interp_plt_sect_low
;
1076 static CORE_ADDR interp_plt_sect_high
;
1079 svr4_in_dynsym_resolve_code (CORE_ADDR pc
)
1081 return ((pc
>= interp_text_sect_low
&& pc
< interp_text_sect_high
)
1082 || (pc
>= interp_plt_sect_low
&& pc
< interp_plt_sect_high
)
1083 || in_plt_section (pc
, NULL
));
1086 /* Given an executable's ABFD and target, compute the entry-point
1090 exec_entry_point (struct bfd
*abfd
, struct target_ops
*targ
)
1092 /* KevinB wrote ... for most targets, the address returned by
1093 bfd_get_start_address() is the entry point for the start
1094 function. But, for some targets, bfd_get_start_address() returns
1095 the address of a function descriptor from which the entry point
1096 address may be extracted. This address is extracted by
1097 gdbarch_convert_from_func_ptr_addr(). The method
1098 gdbarch_convert_from_func_ptr_addr() is the merely the identify
1099 function for targets which don't use function descriptors. */
1100 return gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1101 bfd_get_start_address (abfd
),
1109 enable_break -- arrange for dynamic linker to hit breakpoint
1113 int enable_break (void)
1117 Both the SunOS and the SVR4 dynamic linkers have, as part of their
1118 debugger interface, support for arranging for the inferior to hit
1119 a breakpoint after mapping in the shared libraries. This function
1120 enables that breakpoint.
1122 For SunOS, there is a special flag location (in_debugger) which we
1123 set to 1. When the dynamic linker sees this flag set, it will set
1124 a breakpoint at a location known only to itself, after saving the
1125 original contents of that place and the breakpoint address itself,
1126 in it's own internal structures. When we resume the inferior, it
1127 will eventually take a SIGTRAP when it runs into the breakpoint.
1128 We handle this (in a different place) by restoring the contents of
1129 the breakpointed location (which is only known after it stops),
1130 chasing around to locate the shared libraries that have been
1131 loaded, then resuming.
1133 For SVR4, the debugger interface structure contains a member (r_brk)
1134 which is statically initialized at the time the shared library is
1135 built, to the offset of a function (_r_debug_state) which is guaran-
1136 teed to be called once before mapping in a library, and again when
1137 the mapping is complete. At the time we are examining this member,
1138 it contains only the unrelocated offset of the function, so we have
1139 to do our own relocation. Later, when the dynamic linker actually
1140 runs, it relocates r_brk to be the actual address of _r_debug_state().
1142 The debugger interface structure also contains an enumeration which
1143 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
1144 depending upon whether or not the library is being mapped or unmapped,
1145 and then set to RT_CONSISTENT after the library is mapped/unmapped.
1151 struct minimal_symbol
*msymbol
;
1153 asection
*interp_sect
;
1154 gdb_byte
*interp_name
;
1157 /* First, remove all the solib event breakpoints. Their addresses
1158 may have changed since the last time we ran the program. */
1159 remove_solib_event_breakpoints ();
1161 interp_text_sect_low
= interp_text_sect_high
= 0;
1162 interp_plt_sect_low
= interp_plt_sect_high
= 0;
1164 /* If we already have a shared library list in the target, and
1165 r_debug contains r_brk, set the breakpoint there - this should
1166 mean r_brk has already been relocated. Assume the dynamic linker
1167 is the object containing r_brk. */
1169 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1171 if (debug_base
&& solib_svr4_r_map () != 0)
1172 sym_addr
= solib_svr4_r_brk ();
1176 struct obj_section
*os
;
1178 sym_addr
= gdbarch_addr_bits_remove
1179 (target_gdbarch
, gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1183 os
= find_pc_section (sym_addr
);
1186 /* Record the relocated start and end address of the dynamic linker
1187 text and plt section for svr4_in_dynsym_resolve_code. */
1189 CORE_ADDR load_addr
;
1191 tmp_bfd
= os
->objfile
->obfd
;
1192 load_addr
= ANOFFSET (os
->objfile
->section_offsets
,
1193 os
->objfile
->sect_index_text
);
1195 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1198 interp_text_sect_low
=
1199 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1200 interp_text_sect_high
=
1201 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1203 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1206 interp_plt_sect_low
=
1207 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1208 interp_plt_sect_high
=
1209 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1212 create_solib_event_breakpoint (sym_addr
);
1217 /* Find the program interpreter; if not found, warn the user and drop
1218 into the old breakpoint at symbol code. */
1219 interp_name
= find_program_interpreter ();
1222 CORE_ADDR load_addr
= 0;
1223 int load_addr_found
= 0;
1224 int loader_found_in_list
= 0;
1226 bfd
*tmp_bfd
= NULL
;
1227 struct target_ops
*tmp_bfd_target
;
1228 volatile struct gdb_exception ex
;
1232 /* Now we need to figure out where the dynamic linker was
1233 loaded so that we can load its symbols and place a breakpoint
1234 in the dynamic linker itself.
1236 This address is stored on the stack. However, I've been unable
1237 to find any magic formula to find it for Solaris (appears to
1238 be trivial on GNU/Linux). Therefore, we have to try an alternate
1239 mechanism to find the dynamic linker's base address. */
1241 TRY_CATCH (ex
, RETURN_MASK_ALL
)
1243 tmp_bfd
= solib_bfd_open (interp_name
);
1245 if (tmp_bfd
== NULL
)
1246 goto bkpt_at_symbol
;
1248 /* Now convert the TMP_BFD into a target. That way target, as
1249 well as BFD operations can be used. Note that closing the
1250 target will also close the underlying bfd. */
1251 tmp_bfd_target
= target_bfd_reopen (tmp_bfd
);
1253 /* On a running target, we can get the dynamic linker's base
1254 address from the shared library table. */
1255 so
= master_so_list ();
1258 if (svr4_same_1 (interp_name
, so
->so_original_name
))
1260 load_addr_found
= 1;
1261 loader_found_in_list
= 1;
1262 load_addr
= LM_ADDR_CHECK (so
, tmp_bfd
);
1268 /* If we were not able to find the base address of the loader
1269 from our so_list, then try using the AT_BASE auxilliary entry. */
1270 if (!load_addr_found
)
1271 if (target_auxv_search (¤t_target
, AT_BASE
, &load_addr
) > 0)
1272 load_addr_found
= 1;
1274 /* Otherwise we find the dynamic linker's base address by examining
1275 the current pc (which should point at the entry point for the
1276 dynamic linker) and subtracting the offset of the entry point.
1278 This is more fragile than the previous approaches, but is a good
1279 fallback method because it has actually been working well in
1281 if (!load_addr_found
)
1282 load_addr
= (read_pc ()
1283 - exec_entry_point (tmp_bfd
, tmp_bfd_target
));
1285 if (!loader_found_in_list
)
1287 debug_loader_name
= xstrdup (interp_name
);
1288 debug_loader_offset_p
= 1;
1289 debug_loader_offset
= load_addr
;
1290 solib_add (NULL
, 0, ¤t_target
, auto_solib_add
);
1293 /* Record the relocated start and end address of the dynamic linker
1294 text and plt section for svr4_in_dynsym_resolve_code. */
1295 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".text");
1298 interp_text_sect_low
=
1299 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1300 interp_text_sect_high
=
1301 interp_text_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1303 interp_sect
= bfd_get_section_by_name (tmp_bfd
, ".plt");
1306 interp_plt_sect_low
=
1307 bfd_section_vma (tmp_bfd
, interp_sect
) + load_addr
;
1308 interp_plt_sect_high
=
1309 interp_plt_sect_low
+ bfd_section_size (tmp_bfd
, interp_sect
);
1312 /* Now try to set a breakpoint in the dynamic linker. */
1313 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1315 sym_addr
= bfd_lookup_symbol (tmp_bfd
, *bkpt_namep
);
1321 /* Convert 'sym_addr' from a function pointer to an address.
1322 Because we pass tmp_bfd_target instead of the current
1323 target, this will always produce an unrelocated value. */
1324 sym_addr
= gdbarch_convert_from_func_ptr_addr (target_gdbarch
,
1328 /* We're done with both the temporary bfd and target. Remember,
1329 closing the target closes the underlying bfd. */
1330 target_close (tmp_bfd_target
, 0);
1334 create_solib_event_breakpoint (load_addr
+ sym_addr
);
1335 xfree (interp_name
);
1339 /* For whatever reason we couldn't set a breakpoint in the dynamic
1340 linker. Warn and drop into the old code. */
1342 xfree (interp_name
);
1343 warning (_("Unable to find dynamic linker breakpoint function.\n"
1344 "GDB will be unable to debug shared library initializers\n"
1345 "and track explicitly loaded dynamic code."));
1348 /* Scan through the lists of symbols, trying to look up the symbol and
1349 set a breakpoint there. Terminate loop when we/if we succeed. */
1351 for (bkpt_namep
= solib_break_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1353 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1354 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1356 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1361 for (bkpt_namep
= bkpt_names
; *bkpt_namep
!= NULL
; bkpt_namep
++)
1363 msymbol
= lookup_minimal_symbol (*bkpt_namep
, NULL
, symfile_objfile
);
1364 if ((msymbol
!= NULL
) && (SYMBOL_VALUE_ADDRESS (msymbol
) != 0))
1366 create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol
));
1377 special_symbol_handling -- additional shared library symbol handling
1381 void special_symbol_handling ()
1385 Once the symbols from a shared object have been loaded in the usual
1386 way, we are called to do any system specific symbol handling that
1389 For SunOS4, this consisted of grunging around in the dynamic
1390 linkers structures to find symbol definitions for "common" symbols
1391 and adding them to the minimal symbol table for the runtime common
1394 However, for SVR4, there's nothing to do.
1399 svr4_special_symbol_handling (void)
1403 /* Relocate the main executable. This function should be called upon
1404 stopping the inferior process at the entry point to the program.
1405 The entry point from BFD is compared to the PC and if they are
1406 different, the main executable is relocated by the proper amount.
1408 As written it will only attempt to relocate executables which
1409 lack interpreter sections. It seems likely that only dynamic
1410 linker executables will get relocated, though it should work
1411 properly for a position-independent static executable as well. */
1414 svr4_relocate_main_executable (void)
1416 asection
*interp_sect
;
1417 CORE_ADDR pc
= read_pc ();
1419 /* Decide if the objfile needs to be relocated. As indicated above,
1420 we will only be here when execution is stopped at the beginning
1421 of the program. Relocation is necessary if the address at which
1422 we are presently stopped differs from the start address stored in
1423 the executable AND there's no interpreter section. The condition
1424 regarding the interpreter section is very important because if
1425 there *is* an interpreter section, execution will begin there
1426 instead. When there is an interpreter section, the start address
1427 is (presumably) used by the interpreter at some point to start
1428 execution of the program.
1430 If there is an interpreter, it is normal for it to be set to an
1431 arbitrary address at the outset. The job of finding it is
1432 handled in enable_break().
1434 So, to summarize, relocations are necessary when there is no
1435 interpreter section and the start address obtained from the
1436 executable is different from the address at which GDB is
1439 [ The astute reader will note that we also test to make sure that
1440 the executable in question has the DYNAMIC flag set. It is my
1441 opinion that this test is unnecessary (undesirable even). It
1442 was added to avoid inadvertent relocation of an executable
1443 whose e_type member in the ELF header is not ET_DYN. There may
1444 be a time in the future when it is desirable to do relocations
1445 on other types of files as well in which case this condition
1446 should either be removed or modified to accomodate the new file
1447 type. (E.g, an ET_EXEC executable which has been built to be
1448 position-independent could safely be relocated by the OS if
1449 desired. It is true that this violates the ABI, but the ABI
1450 has been known to be bent from time to time.) - Kevin, Nov 2000. ]
1453 interp_sect
= bfd_get_section_by_name (exec_bfd
, ".interp");
1454 if (interp_sect
== NULL
1455 && (bfd_get_file_flags (exec_bfd
) & DYNAMIC
) != 0
1456 && (exec_entry_point (exec_bfd
, &exec_ops
) != pc
))
1458 struct cleanup
*old_chain
;
1459 struct section_offsets
*new_offsets
;
1461 CORE_ADDR displacement
;
1463 /* It is necessary to relocate the objfile. The amount to
1464 relocate by is simply the address at which we are stopped
1465 minus the starting address from the executable.
1467 We relocate all of the sections by the same amount. This
1468 behavior is mandated by recent editions of the System V ABI.
1469 According to the System V Application Binary Interface,
1470 Edition 4.1, page 5-5:
1472 ... Though the system chooses virtual addresses for
1473 individual processes, it maintains the segments' relative
1474 positions. Because position-independent code uses relative
1475 addressesing between segments, the difference between
1476 virtual addresses in memory must match the difference
1477 between virtual addresses in the file. The difference
1478 between the virtual address of any segment in memory and
1479 the corresponding virtual address in the file is thus a
1480 single constant value for any one executable or shared
1481 object in a given process. This difference is the base
1482 address. One use of the base address is to relocate the
1483 memory image of the program during dynamic linking.
1485 The same language also appears in Edition 4.0 of the System V
1486 ABI and is left unspecified in some of the earlier editions. */
1488 displacement
= pc
- exec_entry_point (exec_bfd
, &exec_ops
);
1491 new_offsets
= xcalloc (symfile_objfile
->num_sections
,
1492 sizeof (struct section_offsets
));
1493 old_chain
= make_cleanup (xfree
, new_offsets
);
1495 for (i
= 0; i
< symfile_objfile
->num_sections
; i
++)
1497 if (displacement
!= ANOFFSET (symfile_objfile
->section_offsets
, i
))
1499 new_offsets
->offsets
[i
] = displacement
;
1503 objfile_relocate (symfile_objfile
, new_offsets
);
1505 do_cleanups (old_chain
);
1513 svr4_solib_create_inferior_hook -- shared library startup support
1517 void svr4_solib_create_inferior_hook ()
1521 When gdb starts up the inferior, it nurses it along (through the
1522 shell) until it is ready to execute it's first instruction. At this
1523 point, this function gets called via expansion of the macro
1524 SOLIB_CREATE_INFERIOR_HOOK.
1526 For SunOS executables, this first instruction is typically the
1527 one at "_start", or a similar text label, regardless of whether
1528 the executable is statically or dynamically linked. The runtime
1529 startup code takes care of dynamically linking in any shared
1530 libraries, once gdb allows the inferior to continue.
1532 For SVR4 executables, this first instruction is either the first
1533 instruction in the dynamic linker (for dynamically linked
1534 executables) or the instruction at "start" for statically linked
1535 executables. For dynamically linked executables, the system
1536 first exec's /lib/libc.so.N, which contains the dynamic linker,
1537 and starts it running. The dynamic linker maps in any needed
1538 shared libraries, maps in the actual user executable, and then
1539 jumps to "start" in the user executable.
1541 For both SunOS shared libraries, and SVR4 shared libraries, we
1542 can arrange to cooperate with the dynamic linker to discover the
1543 names of shared libraries that are dynamically linked, and the
1544 base addresses to which they are linked.
1546 This function is responsible for discovering those names and
1547 addresses, and saving sufficient information about them to allow
1548 their symbols to be read at a later time.
1552 Between enable_break() and disable_break(), this code does not
1553 properly handle hitting breakpoints which the user might have
1554 set in the startup code or in the dynamic linker itself. Proper
1555 handling will probably have to wait until the implementation is
1556 changed to use the "breakpoint handler function" method.
1558 Also, what if child has exit()ed? Must exit loop somehow.
1562 svr4_solib_create_inferior_hook (void)
1564 struct thread_info
*tp
;
1566 /* Relocate the main executable if necessary. */
1567 svr4_relocate_main_executable ();
1569 if (!svr4_have_link_map_offsets ())
1572 if (!enable_break ())
1575 #if defined(_SCO_DS)
1576 /* SCO needs the loop below, other systems should be using the
1577 special shared library breakpoints and the shared library breakpoint
1580 Now run the target. It will eventually hit the breakpoint, at
1581 which point all of the libraries will have been mapped in and we
1582 can go groveling around in the dynamic linker structures to find
1583 out what we need to know about them. */
1585 tp
= inferior_thread ();
1587 clear_proceed_status ();
1588 stop_soon
= STOP_QUIETLY
;
1589 tp
->stop_signal
= TARGET_SIGNAL_0
;
1592 target_resume (pid_to_ptid (-1), 0, tp
->stop_signal
);
1593 wait_for_inferior (0);
1595 while (tp
->stop_signal
!= TARGET_SIGNAL_TRAP
);
1596 stop_soon
= NO_STOP_QUIETLY
;
1597 #endif /* defined(_SCO_DS) */
1601 svr4_clear_solib (void)
1604 debug_loader_offset_p
= 0;
1605 debug_loader_offset
= 0;
1606 xfree (debug_loader_name
);
1607 debug_loader_name
= NULL
;
1612 svr4_free_so (struct so_list
*so
)
1614 xfree (so
->lm_info
->lm
);
1615 xfree (so
->lm_info
);
1619 /* Clear any bits of ADDR that wouldn't fit in a target-format
1620 data pointer. "Data pointer" here refers to whatever sort of
1621 address the dynamic linker uses to manage its sections. At the
1622 moment, we don't support shared libraries on any processors where
1623 code and data pointers are different sizes.
1625 This isn't really the right solution. What we really need here is
1626 a way to do arithmetic on CORE_ADDR values that respects the
1627 natural pointer/address correspondence. (For example, on the MIPS,
1628 converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
1629 sign-extend the value. There, simply truncating the bits above
1630 gdbarch_ptr_bit, as we do below, is no good.) This should probably
1631 be a new gdbarch method or something. */
1633 svr4_truncate_ptr (CORE_ADDR addr
)
1635 if (gdbarch_ptr_bit (target_gdbarch
) == sizeof (CORE_ADDR
) * 8)
1636 /* We don't need to truncate anything, and the bit twiddling below
1637 will fail due to overflow problems. */
1640 return addr
& (((CORE_ADDR
) 1 << gdbarch_ptr_bit (target_gdbarch
)) - 1);
1645 svr4_relocate_section_addresses (struct so_list
*so
,
1646 struct section_table
*sec
)
1648 sec
->addr
= svr4_truncate_ptr (sec
->addr
+ LM_ADDR_CHECK (so
,
1650 sec
->endaddr
= svr4_truncate_ptr (sec
->endaddr
+ LM_ADDR_CHECK (so
,
1655 /* Architecture-specific operations. */
1657 /* Per-architecture data key. */
1658 static struct gdbarch_data
*solib_svr4_data
;
1660 struct solib_svr4_ops
1662 /* Return a description of the layout of `struct link_map'. */
1663 struct link_map_offsets
*(*fetch_link_map_offsets
)(void);
1666 /* Return a default for the architecture-specific operations. */
1669 solib_svr4_init (struct obstack
*obstack
)
1671 struct solib_svr4_ops
*ops
;
1673 ops
= OBSTACK_ZALLOC (obstack
, struct solib_svr4_ops
);
1674 ops
->fetch_link_map_offsets
= NULL
;
1678 /* Set the architecture-specific `struct link_map_offsets' fetcher for
1679 GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
1682 set_solib_svr4_fetch_link_map_offsets (struct gdbarch
*gdbarch
,
1683 struct link_map_offsets
*(*flmo
) (void))
1685 struct solib_svr4_ops
*ops
= gdbarch_data (gdbarch
, solib_svr4_data
);
1687 ops
->fetch_link_map_offsets
= flmo
;
1689 set_solib_ops (gdbarch
, &svr4_so_ops
);
1692 /* Fetch a link_map_offsets structure using the architecture-specific
1693 `struct link_map_offsets' fetcher. */
1695 static struct link_map_offsets
*
1696 svr4_fetch_link_map_offsets (void)
1698 struct solib_svr4_ops
*ops
= gdbarch_data (target_gdbarch
, solib_svr4_data
);
1700 gdb_assert (ops
->fetch_link_map_offsets
);
1701 return ops
->fetch_link_map_offsets ();
1704 /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
1707 svr4_have_link_map_offsets (void)
1709 struct solib_svr4_ops
*ops
= gdbarch_data (target_gdbarch
, solib_svr4_data
);
1710 return (ops
->fetch_link_map_offsets
!= NULL
);
1714 /* Most OS'es that have SVR4-style ELF dynamic libraries define a
1715 `struct r_debug' and a `struct link_map' that are binary compatible
1716 with the origional SVR4 implementation. */
1718 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1719 for an ILP32 SVR4 system. */
1721 struct link_map_offsets
*
1722 svr4_ilp32_fetch_link_map_offsets (void)
1724 static struct link_map_offsets lmo
;
1725 static struct link_map_offsets
*lmp
= NULL
;
1731 lmo
.r_version_offset
= 0;
1732 lmo
.r_version_size
= 4;
1733 lmo
.r_map_offset
= 4;
1734 lmo
.r_brk_offset
= 8;
1735 lmo
.r_ldsomap_offset
= 20;
1737 /* Everything we need is in the first 20 bytes. */
1738 lmo
.link_map_size
= 20;
1739 lmo
.l_addr_offset
= 0;
1740 lmo
.l_name_offset
= 4;
1741 lmo
.l_ld_offset
= 8;
1742 lmo
.l_next_offset
= 12;
1743 lmo
.l_prev_offset
= 16;
1749 /* Fetch (and possibly build) an appropriate `struct link_map_offsets'
1750 for an LP64 SVR4 system. */
1752 struct link_map_offsets
*
1753 svr4_lp64_fetch_link_map_offsets (void)
1755 static struct link_map_offsets lmo
;
1756 static struct link_map_offsets
*lmp
= NULL
;
1762 lmo
.r_version_offset
= 0;
1763 lmo
.r_version_size
= 4;
1764 lmo
.r_map_offset
= 8;
1765 lmo
.r_brk_offset
= 16;
1766 lmo
.r_ldsomap_offset
= 40;
1768 /* Everything we need is in the first 40 bytes. */
1769 lmo
.link_map_size
= 40;
1770 lmo
.l_addr_offset
= 0;
1771 lmo
.l_name_offset
= 8;
1772 lmo
.l_ld_offset
= 16;
1773 lmo
.l_next_offset
= 24;
1774 lmo
.l_prev_offset
= 32;
1781 struct target_so_ops svr4_so_ops
;
1783 /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
1784 different rule for symbol lookup. The lookup begins here in the DSO, not in
1785 the main executable. */
1787 static struct symbol
*
1788 elf_lookup_lib_symbol (const struct objfile
*objfile
,
1790 const char *linkage_name
,
1791 const domain_enum domain
)
1793 if (objfile
->obfd
== NULL
1794 || scan_dyntag (DT_SYMBOLIC
, objfile
->obfd
, NULL
) != 1)
1797 return lookup_global_symbol_from_objfile
1798 (objfile
, name
, linkage_name
, domain
);
1801 extern initialize_file_ftype _initialize_svr4_solib
; /* -Wmissing-prototypes */
1804 _initialize_svr4_solib (void)
1806 solib_svr4_data
= gdbarch_data_register_pre_init (solib_svr4_init
);
1808 svr4_so_ops
.relocate_section_addresses
= svr4_relocate_section_addresses
;
1809 svr4_so_ops
.free_so
= svr4_free_so
;
1810 svr4_so_ops
.clear_solib
= svr4_clear_solib
;
1811 svr4_so_ops
.solib_create_inferior_hook
= svr4_solib_create_inferior_hook
;
1812 svr4_so_ops
.special_symbol_handling
= svr4_special_symbol_handling
;
1813 svr4_so_ops
.current_sos
= svr4_current_sos
;
1814 svr4_so_ops
.open_symbol_file_object
= open_symbol_file_object
;
1815 svr4_so_ops
.in_dynsym_resolve_code
= svr4_in_dynsym_resolve_code
;
1816 svr4_so_ops
.lookup_lib_global_symbol
= elf_lookup_lib_symbol
;
1817 svr4_so_ops
.same
= svr4_same
;