1 /* Find the debuginfo file for a module from its build ID.
2 Copyright (C) 2007, 2009, 2014 Red Hat, Inc.
3 This file is part of elfutils.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
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
11
12 or
13
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
17
18 or both in parallel, as here.
19
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.
24
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/>. */
28
29 #include "libdwflP.h"
30 #include <unistd.h>
31
32
33 int
dwfl_build_id_find_debuginfo(Dwfl_Module * mod,void ** userdata,const char * modname,Dwarf_Addr base,const char * file,const char * debuglink,GElf_Word crc,char ** debuginfo_file_name)34 dwfl_build_id_find_debuginfo (Dwfl_Module *mod,
35 void **userdata __attribute__ ((unused)),
36 const char *modname __attribute__ ((unused)),
37 Dwarf_Addr base __attribute__ ((unused)),
38 const char *file __attribute__ ((unused)),
39 const char *debuglink __attribute__ ((unused)),
40 GElf_Word crc __attribute__ ((unused)),
41 char **debuginfo_file_name)
42 {
43 int fd = -1;
44
45 /* Are we looking for a separate debug file for the main file or for
46 an alternate (dwz multi) debug file? Alternatively we could check
47 whether the dwbias == -1. */
48 if (mod->dw != NULL)
49 {
50 const void *build_id;
51 const char *altname;
52 ssize_t build_id_len = INTUSE(dwelf_dwarf_gnu_debugaltlink) (mod->dw,
53 &altname,
54 &build_id);
55 if (build_id_len > 0)
56 fd = __libdwfl_open_by_build_id (mod, true, debuginfo_file_name,
57 build_id_len, build_id);
58
59 if (fd >= 0)
60 {
61 /* We need to open an Elf handle on the file so we can check its
62 build ID note for validation. Backdoor the handle into the
63 module data structure since we had to open it early anyway. */
64 Dwfl_Error error = __libdw_open_file (&fd, &mod->alt_elf,
65 true, false);
66 if (error != DWFL_E_NOERROR)
67 __libdwfl_seterrno (error);
68 else
69 {
70 const void *alt_build_id;
71 ssize_t alt_len = INTUSE(dwelf_elf_gnu_build_id) (mod->alt_elf,
72 &alt_build_id);
73 if (alt_len > 0 && alt_len == build_id_len
74 && memcmp (build_id, alt_build_id, alt_len) == 0)
75 return fd;
76 else
77 {
78 /* A mismatch! */
79 elf_end (mod->alt_elf);
80 mod->alt_elf = NULL;
81 close (fd);
82 fd = -1;
83 }
84 free (*debuginfo_file_name);
85 *debuginfo_file_name = NULL;
86 errno = 0;
87 }
88 }
89 return fd;
90 }
91
92 /* We don't even have the Dwarf yet and it isn't in the main file.
93 Try to find separate debug file now using the module build id. */
94 const unsigned char *bits;
95 GElf_Addr vaddr;
96
97 if (INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr) > 0)
98 fd = __libdwfl_open_mod_by_build_id (mod, true, debuginfo_file_name);
99 if (fd >= 0)
100 {
101 /* We need to open an Elf handle on the file so we can check its
102 build ID note for validation. Backdoor the handle into the
103 module data structure since we had to open it early anyway. */
104 Dwfl_Error error = __libdw_open_file (&fd, &mod->debug.elf, true, false);
105 if (error != DWFL_E_NOERROR)
106 __libdwfl_seterrno (error);
107 else if (likely (__libdwfl_find_build_id (mod, false,
108 mod->debug.elf) == 2))
109 {
110 /* Also backdoor the gratuitous flag. */
111 mod->debug.valid = true;
112 return fd;
113 }
114 else
115 {
116 /* A mismatch! */
117 elf_end (mod->debug.elf);
118 mod->debug.elf = NULL;
119 close (fd);
120 fd = -1;
121 }
122 free (*debuginfo_file_name);
123 *debuginfo_file_name = NULL;
124 errno = 0;
125 }
126 return fd;
127 }
128 INTDEF (dwfl_build_id_find_debuginfo)
129