1 /* Report modules by examining dynamic linker data structures.
2 Copyright (C) 2008-2013 Red Hat, Inc.
3 This file is part of elfutils.
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
18 or both in parallel, as here.
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
31 #include "../libdw/memory-access.h"
38 /* This element is always provided and always has a constant value.
39 This makes it an easy thing to scan for to discern the format. */
40 #define PROBE_TYPE AT_PHENT
41 #define PROBE_VAL32 sizeof (Elf32_Phdr)
42 #define PROBE_VAL64 sizeof (Elf64_Phdr)
45 /* Examine an auxv data block and determine its format.
46 Return true iff we figured it out. */
48 auxv_format_probe (const void *auxv, size_t size,
49 uint_fast8_t *elfclass, uint_fast8_t *elfdata)
54 Elf32_auxv_t a32[size / sizeof (Elf32_auxv_t)];
55 Elf64_auxv_t a64[size / sizeof (Elf64_auxv_t)];
58 inline bool check64 (size_t i)
60 /* The AUXV pointer might not even be naturally aligned for 64-bit
61 data, because note payloads in a core file are not aligned.
62 But we assume the data is 32-bit aligned. */
64 uint64_t type = read_8ubyte_unaligned_noncvt (&u->a64[i].a_type);
65 uint64_t val = read_8ubyte_unaligned_noncvt (&u->a64[i].a_un.a_val);
67 if (type == BE64 (PROBE_TYPE)
68 && val == BE64 (PROBE_VAL64))
70 *elfdata = ELFDATA2MSB;
74 if (type == LE64 (PROBE_TYPE)
75 && val == LE64 (PROBE_VAL64))
77 *elfdata = ELFDATA2LSB;
84 inline bool check32 (size_t i)
86 if (u->a32[i].a_type == BE32 (PROBE_TYPE)
87 && u->a32[i].a_un.a_val == BE32 (PROBE_VAL32))
89 *elfdata = ELFDATA2MSB;
93 if (u->a32[i].a_type == LE32 (PROBE_TYPE)
94 && u->a32[i].a_un.a_val == LE32 (PROBE_VAL32))
96 *elfdata = ELFDATA2LSB;
103 for (size_t i = 0; i < size / sizeof (Elf64_auxv_t); ++i)
107 *elfclass = ELFCLASS64;
111 if (check32 (i * 2) || check32 (i * 2 + 1))
113 *elfclass = ELFCLASS32;
121 /* This is a Dwfl_Memory_Callback that wraps another memory callback.
122 If the underlying callback cannot fill the data, then this will
123 fall back to fetching data from module files. */
125 struct integrated_memory_callback
127 Dwfl_Memory_Callback *memory_callback;
128 void *memory_callback_arg;
133 integrated_memory_callback (Dwfl *dwfl, int ndx,
134 void **buffer, size_t *buffer_available,
139 struct integrated_memory_callback *info = arg;
143 /* Called for cleanup. */
144 if (info->buffer != NULL)
146 /* The last probe buffer came from the underlying callback.
147 Let it do its cleanup. */
148 assert (*buffer == info->buffer); /* XXX */
149 *buffer = info->buffer;
151 return (*info->memory_callback) (dwfl, ndx, buffer, buffer_available,
153 info->memory_callback_arg);
156 *buffer_available = 0;
161 /* For a final-read request, we only use the underlying callback. */
162 return (*info->memory_callback) (dwfl, ndx, buffer, buffer_available,
163 vaddr, minread, info->memory_callback_arg);
165 /* Let the underlying callback try to fill this request. */
166 if ((*info->memory_callback) (dwfl, ndx, &info->buffer, buffer_available,
167 vaddr, minread, info->memory_callback_arg))
169 *buffer = info->buffer;
173 /* Now look for module text covering this address. */
176 (void) INTUSE(dwfl_addrsegment) (dwfl, vaddr, &mod);
181 Elf_Scn *scn = INTUSE(dwfl_module_address_section) (mod, &vaddr, &bias);
182 if (unlikely (scn == NULL))
184 #if 0 // XXX would have to handle ndx=-1 cleanup calls passed down.
185 /* If we have no sections we can try to fill it from the module file
186 based on its phdr mappings. */
187 if (likely (mod->e_type != ET_REL) && mod->main.elf != NULL)
188 return INTUSE(dwfl_elf_phdr_memory_callback)
189 (dwfl, 0, buffer, buffer_available,
190 vaddr - mod->main.bias, minread, mod->main.elf);
195 Elf_Data *data = elf_rawdata (scn, NULL);
196 if (unlikely (data == NULL))
200 if (unlikely (data->d_size < vaddr))
203 /* Provide as much data as we have. */
204 void *contents = data->d_buf + vaddr;
205 size_t avail = data->d_size - vaddr;
206 if (unlikely (avail < minread))
209 /* If probing for a string, make sure it's terminated. */
210 if (minread == 0 && unlikely (memchr (contents, '\0', avail) == NULL))
215 *buffer_available = avail;
220 addrsize (uint_fast8_t elfclass)
225 /* Report a module for each struct link_map in the linked list at r_map
226 in the struct r_debug at R_DEBUG_VADDR. For r_debug_info description
227 see dwfl_link_map_report in libdwflP.h. If R_DEBUG_INFO is not NULL then no
228 modules get added to DWFL, caller has to add them from filled in
231 For each link_map entry, if an existing module resides at its address,
232 this just modifies that module's name and suggested file name. If
233 no such module exists, this calls dwfl_report_elf on the l_name string.
235 Returns the number of modules found, or -1 for errors. */
238 report_r_debug (uint_fast8_t elfclass, uint_fast8_t elfdata,
239 Dwfl *dwfl, GElf_Addr r_debug_vaddr,
240 Dwfl_Memory_Callback *memory_callback,
241 void *memory_callback_arg,
242 struct r_debug_info *r_debug_info)
244 /* Skip r_version, to aligned r_map field. */
245 GElf_Addr read_vaddr = r_debug_vaddr + addrsize (elfclass);
248 size_t buffer_available = 0;
249 inline int release_buffer (int result)
252 (void) (*memory_callback) (dwfl, -1, &buffer, &buffer_available, 0, 0,
253 memory_callback_arg);
258 inline bool read_addrs (GElf_Addr vaddr, size_t n)
260 size_t nb = n * addrsize (elfclass); /* Address words -> bytes to read. */
262 /* Read a new buffer if the old one doesn't cover these words. */
264 || vaddr < read_vaddr
265 || vaddr - read_vaddr + nb > buffer_available)
270 int segndx = INTUSE(dwfl_addrsegment) (dwfl, vaddr, NULL);
271 if (unlikely (segndx < 0)
272 || unlikely (! (*memory_callback) (dwfl, segndx,
273 &buffer, &buffer_available,
274 vaddr, nb, memory_callback_arg)))
282 } *in = vaddr - read_vaddr + buffer;
284 if (elfclass == ELFCLASS32)
286 if (elfdata == ELFDATA2MSB)
287 for (size_t i = 0; i < n; ++i)
288 addrs[i] = BE32 (in->a32[i]);
290 for (size_t i = 0; i < n; ++i)
291 addrs[i] = LE32 (in->a32[i]);
295 if (elfdata == ELFDATA2MSB)
296 for (size_t i = 0; i < n; ++i)
297 addrs[i] = BE64 (in->a64[i]);
299 for (size_t i = 0; i < n; ++i)
300 addrs[i] = LE64 (in->a64[i]);
306 if (unlikely (read_addrs (read_vaddr, 1)))
307 return release_buffer (-1);
309 GElf_Addr next = addrs[0];
311 Dwfl_Module **lastmodp = &dwfl->modulelist;
314 /* There can't be more elements in the link_map list than there are
315 segments. DWFL->lookup_elts is probably twice that number, so it
316 is certainly above the upper bound. If we iterate too many times,
317 there must be a loop in the pointers due to link_map clobberation. */
318 size_t iterations = 0;
319 while (next != 0 && ++iterations < dwfl->lookup_elts)
321 if (read_addrs (next, 4))
322 return release_buffer (-1);
324 /* Unused: l_addr is the difference between the address in memory
325 and the ELF file when the core was created. We need to
326 recalculate the difference below because the ELF file we use
327 might be differently pre-linked. */
328 // GElf_Addr l_addr = addrs[0];
329 GElf_Addr l_name = addrs[1];
330 GElf_Addr l_ld = addrs[2];
333 /* If a clobbered or truncated memory image has no useful pointer,
334 just skip this element. */
338 /* Fetch the string at the l_name address. */
339 const char *name = NULL;
341 && read_vaddr <= l_name
342 && l_name + 1 - read_vaddr < buffer_available
343 && memchr (l_name - read_vaddr + buffer, '\0',
344 buffer_available - (l_name - read_vaddr)) != NULL)
345 name = l_name - read_vaddr + buffer;
350 int segndx = INTUSE(dwfl_addrsegment) (dwfl, l_name, NULL);
351 if (likely (segndx >= 0)
352 && (*memory_callback) (dwfl, segndx,
353 &buffer, &buffer_available,
354 l_name, 0, memory_callback_arg))
358 if (name != NULL && name[0] == '\0')
361 if (iterations == 1 && dwfl->executable_for_core != NULL)
362 name = dwfl->executable_for_core;
364 struct r_debug_info_module *r_debug_info_module = NULL;
365 if (r_debug_info != NULL)
367 /* Save link map information about valid shared library (or
368 executable) which has not been found on disk. */
369 const char *name1 = name == NULL ? "" : name;
370 r_debug_info_module = malloc (sizeof (*r_debug_info_module)
371 + strlen (name1) + 1);
372 if (r_debug_info_module == NULL)
373 return release_buffer (result);
374 r_debug_info_module->fd = -1;
375 r_debug_info_module->elf = NULL;
376 r_debug_info_module->l_ld = l_ld;
377 r_debug_info_module->start = 0;
378 r_debug_info_module->end = 0;
379 r_debug_info_module->disk_file_has_build_id = false;
380 strcpy (r_debug_info_module->name, name1);
381 r_debug_info_module->next = r_debug_info->module;
382 r_debug_info->module = r_debug_info_module;
385 Dwfl_Module *mod = NULL;
388 /* This code is mostly inlined dwfl_report_elf. */
389 // XXX hook for sysroot
390 int fd = open64 (name, O_RDONLY);
394 Dwfl_Error error = __libdw_open_file (&fd, &elf, true, false);
395 GElf_Addr elf_dynamic_vaddr;
396 if (error == DWFL_E_NOERROR
397 && __libdwfl_dynamic_vaddr_get (elf, &elf_dynamic_vaddr))
399 const void *build_id_bits;
400 GElf_Addr build_id_elfaddr;
404 if (__libdwfl_find_elf_build_id (NULL, elf, &build_id_bits,
407 && build_id_elfaddr != 0)
409 if (r_debug_info_module != NULL)
410 r_debug_info_module->disk_file_has_build_id = true;
411 GElf_Addr build_id_vaddr = (build_id_elfaddr
412 - elf_dynamic_vaddr + l_ld);
415 int segndx = INTUSE(dwfl_addrsegment) (dwfl,
418 if (! (*memory_callback) (dwfl, segndx,
419 &buffer, &buffer_available,
420 build_id_vaddr, build_id_len,
421 memory_callback_arg))
423 /* File has valid build-id which cannot be read from
424 memory. This happens for core files without bit 4
425 (0x10) set in Linux /proc/PID/coredump_filter. */
429 if (memcmp (build_id_bits, buffer, build_id_len) != 0)
430 /* File has valid build-id which does not match
431 the one in memory. */
439 // It is like l_addr but it handles differently prelinked
440 // files at core dumping vs. core loading time.
441 GElf_Addr base = l_ld - elf_dynamic_vaddr;
442 if (r_debug_info_module == NULL)
444 // XXX hook for sysroot
445 mod = __libdwfl_report_elf (dwfl, basename (name),
454 else if (__libdwfl_elf_address_range (elf, base, true,
456 &r_debug_info_module->start,
457 &r_debug_info_module->end,
460 r_debug_info_module->elf = elf;
461 r_debug_info_module->fd = fd;
478 /* Move this module to the end of the list, so that we end
479 up with a list in the same order as the link_map chain. */
480 if (mod->next != NULL)
482 if (*lastmodp != mod)
484 lastmodp = &dwfl->modulelist;
485 while (*lastmodp != mod)
486 lastmodp = &(*lastmodp)->next;
488 *lastmodp = mod->next;
490 while (*lastmodp != NULL)
491 lastmodp = &(*lastmodp)->next;
495 lastmodp = &mod->next;
499 return release_buffer (result);
503 consider_executable (Dwfl_Module *mod, GElf_Addr at_phdr, GElf_Addr at_entry,
504 uint_fast8_t *elfclass, uint_fast8_t *elfdata,
505 Dwfl_Memory_Callback *memory_callback,
506 void *memory_callback_arg)
509 if (unlikely (gelf_getehdr (mod->main.elf, &ehdr) == NULL))
514 /* If we have an AT_ENTRY value, reject this executable if
515 its entry point address could not have supplied that. */
517 if (ehdr.e_entry == 0)
520 if (mod->e_type == ET_EXEC)
522 if (ehdr.e_entry != at_entry)
527 /* It could be a PIE. */
531 // XXX this could be saved in the file cache: phdr vaddr, DT_DEBUG d_val vaddr
532 /* Find the vaddr of the DT_DEBUG's d_ptr. This is the memory
533 address where &r_debug was written at runtime. */
534 GElf_Xword align = mod->dwfl->segment_align;
535 GElf_Addr d_val_vaddr = 0;
536 for (uint_fast16_t i = 0; i < ehdr.e_phnum; ++i)
539 GElf_Phdr *phdr = gelf_getphdr (mod->main.elf, i, &phdr_mem);
543 if (phdr->p_align > 1 && (align == 0 || phdr->p_align < align))
544 align = phdr->p_align;
547 && phdr->p_type == PT_LOAD
548 && (phdr->p_offset & -align) == (ehdr.e_phoff & -align))
550 /* This is the segment that would map the phdrs.
551 If we have an AT_PHDR value, reject this executable
552 if its phdr mapping could not have supplied that. */
553 if (mod->e_type == ET_EXEC)
555 if (ehdr.e_phoff - phdr->p_offset + phdr->p_vaddr != at_phdr)
560 /* It could be a PIE. If the AT_PHDR value and our
561 phdr address don't match modulo ALIGN, then this
562 could not have been the right PIE. */
563 if (((ehdr.e_phoff - phdr->p_offset + phdr->p_vaddr) & -align)
564 != (at_phdr & -align))
567 /* Calculate the bias applied to the PIE's p_vaddr values. */
568 GElf_Addr bias = (at_phdr - (ehdr.e_phoff - phdr->p_offset
571 /* Final sanity check: if we have an AT_ENTRY value,
572 reject this PIE unless its biased e_entry matches. */
573 if (at_entry != 0 && at_entry != ehdr.e_entry + bias)
576 /* If we're changing the module's address range,
577 we've just invalidated the module lookup table. */
578 GElf_Addr mod_bias = dwfl_adjusted_address (mod, 0);
579 if (bias != mod_bias)
581 mod->low_addr -= mod_bias;
582 mod->high_addr -= mod_bias;
583 mod->low_addr += bias;
584 mod->high_addr += bias;
586 free (mod->dwfl->lookup_module);
587 mod->dwfl->lookup_module = NULL;
592 if (phdr->p_type == PT_DYNAMIC)
594 Elf_Data *data = elf_getdata_rawchunk (mod->main.elf, phdr->p_offset,
595 phdr->p_filesz, ELF_T_DYN);
598 const size_t entsize = gelf_fsize (mod->main.elf,
599 ELF_T_DYN, 1, EV_CURRENT);
600 const size_t n = data->d_size / entsize;
601 for (size_t j = 0; j < n; ++j)
604 GElf_Dyn *dyn = gelf_getdyn (data, j, &dyn_mem);
605 if (dyn != NULL && dyn->d_tag == DT_DEBUG)
607 d_val_vaddr = phdr->p_vaddr + entsize * j + entsize / 2;
614 if (d_val_vaddr != 0)
616 /* Now we have the final address from which to read &r_debug. */
617 d_val_vaddr = dwfl_adjusted_address (mod, d_val_vaddr);
620 size_t buffer_available = addrsize (ehdr.e_ident[EI_CLASS]);
622 int segndx = INTUSE(dwfl_addrsegment) (mod->dwfl, d_val_vaddr, NULL);
624 if ((*memory_callback) (mod->dwfl, segndx,
625 &buffer, &buffer_available,
626 d_val_vaddr, buffer_available,
627 memory_callback_arg))
636 if (ehdr.e_ident[EI_CLASS] == ELFCLASS32)
637 vaddr = (ehdr.e_ident[EI_DATA] == ELFDATA2MSB
638 ? BE32 (u->a32) : LE32 (u->a32));
640 vaddr = (ehdr.e_ident[EI_DATA] == ELFDATA2MSB
641 ? BE64 (u->a64) : LE64 (u->a64));
643 (*memory_callback) (mod->dwfl, -1, &buffer, &buffer_available, 0, 0,
644 memory_callback_arg);
646 if (*elfclass == ELFCLASSNONE)
647 *elfclass = ehdr.e_ident[EI_CLASS];
648 else if (*elfclass != ehdr.e_ident[EI_CLASS])
651 if (*elfdata == ELFDATANONE)
652 *elfdata = ehdr.e_ident[EI_DATA];
653 else if (*elfdata != ehdr.e_ident[EI_DATA])
663 /* Try to find an existing executable module with a DT_DEBUG. */
665 find_executable (Dwfl *dwfl, GElf_Addr at_phdr, GElf_Addr at_entry,
666 uint_fast8_t *elfclass, uint_fast8_t *elfdata,
667 Dwfl_Memory_Callback *memory_callback,
668 void *memory_callback_arg)
670 for (Dwfl_Module *mod = dwfl->modulelist; mod != NULL; mod = mod->next)
671 if (mod->main.elf != NULL)
673 GElf_Addr r_debug_vaddr = consider_executable (mod, at_phdr, at_entry,
676 memory_callback_arg);
677 if (r_debug_vaddr != 0)
678 return r_debug_vaddr;
686 dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size,
687 Dwfl_Memory_Callback *memory_callback,
688 void *memory_callback_arg,
689 struct r_debug_info *r_debug_info)
691 GElf_Addr r_debug_vaddr = 0;
693 uint_fast8_t elfclass = ELFCLASSNONE;
694 uint_fast8_t elfdata = ELFDATANONE;
695 if (likely (auxv != NULL)
696 && likely (auxv_format_probe (auxv, auxv_size, &elfclass, &elfdata)))
700 GElf_Xword phent = 0;
701 GElf_Xword phnum = 0;
703 #define READ_AUXV32(ptr) read_4ubyte_unaligned_noncvt (ptr)
704 #define READ_AUXV64(ptr) read_8ubyte_unaligned_noncvt (ptr)
705 #define AUXV_SCAN(NN, BL) do \
707 const Elf##NN##_auxv_t *av = auxv; \
708 for (size_t i = 0; i < auxv_size / sizeof av[0]; ++i) \
710 uint##NN##_t type = READ_AUXV##NN (&av[i].a_type); \
711 uint##NN##_t val = BL##NN (READ_AUXV##NN (&av[i].a_un.a_val)); \
712 if (type == BL##NN (AT_ENTRY)) \
714 else if (type == BL##NN (AT_PHDR)) \
716 else if (type == BL##NN (AT_PHNUM)) \
718 else if (type == BL##NN (AT_PHENT)) \
720 else if (type == BL##NN (AT_PAGESZ)) \
723 && (dwfl->segment_align == 0 \
724 || val < dwfl->segment_align)) \
725 dwfl->segment_align = val; \
731 if (elfclass == ELFCLASS32)
733 if (elfdata == ELFDATA2MSB)
740 if (elfdata == ELFDATA2MSB)
746 /* If we found the phdr dimensions, search phdrs for PT_DYNAMIC. */
747 GElf_Addr dyn_vaddr = 0;
748 GElf_Xword dyn_filesz = 0;
749 GElf_Addr dyn_bias = (GElf_Addr) -1;
751 inline bool consider_phdr (GElf_Word type,
752 GElf_Addr vaddr, GElf_Xword filesz)
757 if (dyn_bias == (GElf_Addr) -1
758 /* Do a sanity check on the putative address. */
759 && ((vaddr & (dwfl->segment_align - 1))
760 == (phdr & (dwfl->segment_align - 1))))
762 dyn_bias = phdr - vaddr;
763 return dyn_vaddr != 0;
770 return dyn_bias != (GElf_Addr) -1;
776 if (phdr != 0 && phnum != 0)
778 Dwfl_Module *phdr_mod;
779 int phdr_segndx = INTUSE(dwfl_addrsegment) (dwfl, phdr, &phdr_mod);
782 .d_type = ELF_T_PHDR,
783 .d_version = EV_CURRENT,
784 .d_size = phnum * phent,
787 bool in_ok = (*memory_callback) (dwfl, phdr_segndx, &in.d_buf,
788 &in.d_size, phdr, phnum * phent,
789 memory_callback_arg);
790 if (! in_ok && dwfl->executable_for_core != NULL)
792 /* AUXV -> PHDR -> DYNAMIC
793 Both AUXV and DYNAMIC should be always present in a core file.
794 PHDR may be missing in core file, try to read it from
795 EXECUTABLE_FOR_CORE to find where DYNAMIC is located in the
798 int fd = open (dwfl->executable_for_core, O_RDONLY);
800 Dwfl_Error error = DWFL_E_ERRNO;
802 error = __libdw_open_file (&fd, &elf, true, false);
803 if (error != DWFL_E_NOERROR)
805 __libdwfl_seterrno (error);
808 GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem);
813 __libdwfl_seterrno (DWFL_E_LIBELF);
816 if (ehdr->e_phnum != phnum || ehdr->e_phentsize != phent)
820 __libdwfl_seterrno (DWFL_E_BADELF);
823 off_t off = ehdr->e_phoff;
824 assert (in.d_buf == NULL);
825 assert (in.d_size == phnum * phent);
826 in.d_buf = malloc (in.d_size);
827 if (unlikely (in.d_buf == NULL))
831 __libdwfl_seterrno (DWFL_E_NOMEM);
834 ssize_t nread = pread_retry (fd, in.d_buf, in.d_size, off);
837 if (nread != (ssize_t) in.d_size)
840 __libdwfl_seterrno (DWFL_E_ERRNO);
851 char data[phnum * phent];
855 .d_type = ELF_T_PHDR,
856 .d_version = EV_CURRENT,
857 .d_size = phnum * phent,
860 in.d_size = out.d_size;
861 if (likely ((elfclass == ELFCLASS32
862 ? elf32_xlatetom : elf64_xlatetom)
863 (&out, &in, elfdata) != NULL))
865 /* We are looking for PT_DYNAMIC. */
868 Elf32_Phdr p32[phnum];
869 Elf64_Phdr p64[phnum];
870 } *u = (void *) &buf;
871 if (elfclass == ELFCLASS32)
873 for (size_t i = 0; i < phnum; ++i)
874 if (consider_phdr (u->p32[i].p_type,
881 for (size_t i = 0; i < phnum; ++i)
882 if (consider_phdr (u->p64[i].p_type,
889 (*memory_callback) (dwfl, -1, &in.d_buf, &in.d_size, 0, 0,
890 memory_callback_arg);
893 /* We could not read the executable's phdrs from the
894 memory image. If we have a presupplied executable,
895 we can still use the AT_PHDR and AT_ENTRY values to
896 verify it, and to adjust its bias if it's a PIE.
898 If there was an ET_EXEC module presupplied that contains
899 the AT_PHDR address, then we only consider that one.
900 We'll either accept it if its phdr location and e_entry
901 make sense or reject it if they don't. If there is no
902 presupplied ET_EXEC, then look for a presupplied module,
903 which might be a PIE (ET_DYN) that needs its bias adjusted. */
904 r_debug_vaddr = ((phdr_mod == NULL
905 || phdr_mod->main.elf == NULL
906 || phdr_mod->e_type != ET_EXEC)
907 ? find_executable (dwfl, phdr, entry,
911 : consider_executable (phdr_mod, phdr, entry,
914 memory_callback_arg));
917 /* If we found PT_DYNAMIC, search it for DT_DEBUG. */
920 if (dyn_bias != (GElf_Addr) -1)
921 dyn_vaddr += dyn_bias;
926 .d_version = EV_CURRENT,
927 .d_size = dyn_filesz,
930 int dyn_segndx = dwfl_addrsegment (dwfl, dyn_vaddr, NULL);
931 if ((*memory_callback) (dwfl, dyn_segndx, &in.d_buf, &in.d_size,
932 dyn_vaddr, dyn_filesz, memory_callback_arg))
938 char data[dyn_filesz];
943 .d_version = EV_CURRENT,
944 .d_size = dyn_filesz,
947 in.d_size = out.d_size;
948 if (likely ((elfclass == ELFCLASS32
949 ? elf32_xlatetom : elf64_xlatetom)
950 (&out, &in, elfdata) != NULL))
952 /* We are looking for DT_DEBUG. */
955 Elf32_Dyn d32[dyn_filesz / sizeof (Elf32_Dyn)];
956 Elf64_Dyn d64[dyn_filesz / sizeof (Elf64_Dyn)];
957 } *u = (void *) &buf;
958 if (elfclass == ELFCLASS32)
960 size_t n = dyn_filesz / sizeof (Elf32_Dyn);
961 for (size_t i = 0; i < n; ++i)
962 if (u->d32[i].d_tag == DT_DEBUG)
964 r_debug_vaddr = u->d32[i].d_un.d_val;
970 size_t n = dyn_filesz / sizeof (Elf64_Dyn);
971 for (size_t i = 0; i < n; ++i)
972 if (u->d64[i].d_tag == DT_DEBUG)
974 r_debug_vaddr = u->d64[i].d_un.d_val;
980 (*memory_callback) (dwfl, -1, &in.d_buf, &in.d_size, 0, 0,
981 memory_callback_arg);
986 /* We have to look for a presupplied executable file to determine
987 the vaddr of its dynamic section and DT_DEBUG therein. */
988 r_debug_vaddr = find_executable (dwfl, 0, 0, &elfclass, &elfdata,
989 memory_callback, memory_callback_arg);
991 if (r_debug_vaddr == 0)
994 /* For following pointers from struct link_map, we will use an
995 integrated memory access callback that can consult module text
996 elided from the core file. This is necessary when the l_name
997 pointer for the dynamic linker's own entry is a pointer into the
998 executable's .interp section. */
999 struct integrated_memory_callback mcb =
1001 .memory_callback = memory_callback,
1002 .memory_callback_arg = memory_callback_arg
1005 /* Now we can follow the dynamic linker's library list. */
1006 return report_r_debug (elfclass, elfdata, dwfl, r_debug_vaddr,
1007 &integrated_memory_callback, &mcb, r_debug_info);
1009 INTDEF (dwfl_link_map_report)