1 /* Recover relocatibility for addresses computed from debug information.
2 Copyright (C) 2005-2009, 2012 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/>. */
33 /* Since dwfl_report_elf lays out the sections already, this will only be
34 called when the section headers of the debuginfo file are being
35 consulted instead, or for the section placed at 0. With binutils
36 strip-to-debug, the symbol table is in the debuginfo file and relocation
39 dwfl_offline_section_address (Dwfl_Module *mod,
40 void **userdata __attribute__ ((unused)),
41 const char *modname __attribute__ ((unused)),
42 Dwarf_Addr base __attribute__ ((unused)),
43 const char *secname __attribute__ ((unused)),
45 const GElf_Shdr *shdr __attribute__ ((unused)),
48 assert (mod->e_type == ET_REL);
49 assert (shdr->sh_addr == 0);
50 assert (shdr->sh_flags & SHF_ALLOC);
53 if (mod->debug.elf == NULL)
54 /* We are only here because sh_addr is zero even though layout is complete.
55 The first section in the first file under -e is placed at 0. */
58 /* The section numbers might not match between the two files.
59 The best we can rely on is the order of SHF_ALLOC sections. */
61 Elf_Scn *ourscn = elf_getscn (mod->debug.elf, shndx);
63 uint_fast32_t skip_alloc = 0;
64 while ((scn = elf_nextscn (mod->debug.elf, scn)) != ourscn)
68 GElf_Shdr *sh = gelf_getshdr (scn, &shdr_mem);
69 if (unlikely (sh == NULL))
71 if (sh->sh_flags & SHF_ALLOC)
76 while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
79 GElf_Shdr *main_shdr = gelf_getshdr (scn, &shdr_mem);
80 if (unlikely (main_shdr == NULL))
82 if ((main_shdr->sh_flags & SHF_ALLOC) && skip_alloc-- == 0)
84 assert (main_shdr->sh_flags == shdr->sh_flags);
85 *addr = main_shdr->sh_addr;
90 /* This should never happen. */
93 INTDEF (dwfl_offline_section_address)
95 /* Forward declarations. */
96 static Dwfl_Module *process_elf (Dwfl *dwfl, const char *name,
97 const char *file_name, int fd, Elf *elf);
98 static Dwfl_Module *process_archive (Dwfl *dwfl, const char *name,
99 const char *file_name, int fd, Elf *elf,
100 int (*predicate) (const char *module,
103 /* Report one module for an ELF file, or many for an archive.
104 Always consumes ELF and FD. */
106 process_file (Dwfl *dwfl, const char *name, const char *file_name, int fd,
107 Elf *elf, int (*predicate) (const char *module,
110 switch (elf_kind (elf))
114 __libdwfl_seterrno (elf == NULL ? DWFL_E_LIBELF : DWFL_E_BADELF);
118 return process_elf (dwfl, name, file_name, fd, elf);
121 return process_archive (dwfl, name, file_name, fd, elf, predicate);
125 /* Report the open ELF file as a module. Always consumes ELF and FD. */
127 process_elf (Dwfl *dwfl, const char *name, const char *file_name, int fd,
130 Dwfl_Module *mod = __libdwfl_report_elf (dwfl, name, file_name, fd, elf,
131 dwfl->offline_next_address, true,
135 /* If this is an ET_EXEC file with fixed addresses, the address range
136 it consumed may or may not intersect with the arbitrary range we
137 will use for relocatable modules. Make sure we always use a free
138 range for the offline allocations. If this module did use
139 offline_next_address, it may have rounded it up for the module's
140 alignment requirements. */
141 if ((dwfl->offline_next_address >= mod->low_addr
142 || mod->low_addr - dwfl->offline_next_address < OFFLINE_REDZONE)
143 && dwfl->offline_next_address < mod->high_addr + OFFLINE_REDZONE)
144 dwfl->offline_next_address = mod->high_addr + OFFLINE_REDZONE;
146 /* Don't keep the file descriptor around. */
147 if (mod->main.fd != -1 && elf_cntl (mod->main.elf, ELF_C_FDREAD) == 0)
149 close (mod->main.fd);
157 /* Always consumes MEMBER. Returns elf_next result on success.
158 For errors returns ELF_C_NULL with *MOD set to null. */
160 process_archive_member (Dwfl *dwfl, const char *name, const char *file_name,
161 int (*predicate) (const char *module, const char *file),
162 int fd, Elf *member, Dwfl_Module **mod)
164 const Elf_Arhdr *h = elf_getarhdr (member);
165 if (unlikely (h == NULL))
167 __libdwfl_seterrno (DWFL_E_LIBELF);
174 if (!strcmp (h->ar_name, "/") || !strcmp (h->ar_name, "//")
175 || !strcmp (h->ar_name, "/SYM64/"))
178 /* Skip this and go to the next. */
179 Elf_Cmd result = elf_next (member);
185 if (unlikely (asprintf (&member_name, "%s(%s)", file_name, h->ar_name) < 0))
188 __libdwfl_seterrno (DWFL_E_NOMEM);
194 char *module_name = NULL;
195 if (name == NULL || name[0] == '\0')
197 else if (unlikely (asprintf (&module_name, "%s:%s", name, h->ar_name) < 0))
205 if (predicate != NULL)
207 /* Let the predicate decide whether to use this one. */
208 int want = (*predicate) (name, member_name);
213 if (unlikely (want < 0))
215 __libdwfl_seterrno (DWFL_E_CB);
222 /* We let __libdwfl_report_elf cache the fd in mod->main.fd,
223 though it's the same fd for all the members.
224 On module teardown we will close it only on the last Elf reference. */
225 *mod = process_file (dwfl, name, member_name, fd, member, predicate);
229 if (*mod == NULL) /* process_file called elf_end. */
232 /* Advance the archive-reading offset for the next iteration. */
233 return elf_next (member);
236 /* Report each member of the archive as its own module. */
238 process_archive (Dwfl *dwfl, const char *name, const char *file_name, int fd,
240 int (*predicate) (const char *module, const char *file))
243 Dwfl_Module *mod = NULL;
244 Elf *member = elf_begin (fd, ELF_C_READ_MMAP_PRIVATE, archive);
245 if (unlikely (member == NULL)) /* Empty archive. */
247 __libdwfl_seterrno (DWFL_E_BADELF);
251 while (process_archive_member (dwfl, name, file_name, predicate,
252 fd, member, &mod) != ELF_C_NULL)
253 member = elf_begin (fd, ELF_C_READ_MMAP_PRIVATE, archive);
255 /* We can drop the archive Elf handle even if we're still using members
256 in live modules. When the last module's elf_end on a member returns
257 zero, that module will close FD. If no modules survived the predicate,
258 we are all done with the file right here. */
259 if (mod != NULL /* If no modules, caller will clean up. */
260 && elf_end (archive) == 0)
268 __libdwfl_report_offline (Dwfl *dwfl, const char *name,
269 const char *file_name, int fd, bool closefd,
270 int (*predicate) (const char *module,
274 Dwfl_Error error = __libdw_open_file (&fd, &elf, closefd, true);
275 if (error != DWFL_E_NOERROR)
277 __libdwfl_seterrno (error);
280 Dwfl_Module *mod = process_file (dwfl, name, file_name, fd, elf, predicate);
291 dwfl_report_offline (Dwfl *dwfl, const char *name,
292 const char *file_name, int fd)
297 bool closefd = false;
301 fd = open (file_name, O_RDONLY);
304 __libdwfl_seterrno (DWFL_E_ERRNO);
309 return __libdwfl_report_offline (dwfl, name, file_name, fd, closefd, NULL);
311 INTDEF (dwfl_report_offline)