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/tmp/gdb-7.10/gdb/build-id.c
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1 /* build-id-related functions.
2 
3  Copyright (C) 1991-2015 Free Software Foundation, Inc.
4 
5  This file is part of GDB.
6 
7  This program is free software; you can redistribute it and/or modify
8  it under the terms of the GNU General Public License as published by
9  the Free Software Foundation; either version 3 of the License, or
10  (at your option) any later version.
11 
12  This program is distributed in the hope that it will be useful,
13  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  GNU General Public License for more details.
16 
17  You should have received a copy of the GNU General Public License
18  along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 
20 #include "defs.h"
21 #include "bfd.h"
22 #include "gdb_bfd.h"
23 #include "build-id.h"
24 #include "gdb_vecs.h"
25 #include "symfile.h"
26 #include "objfiles.h"
27 #include "filenames.h"
28 #include "gdbcore.h"
29 
30 /* See build-id.h. */
31 
32 const struct bfd_build_id *
33 build_id_bfd_get (bfd *abfd)
34 {
35  if (!bfd_check_format (abfd, bfd_object))
36  return NULL;
37 
38  if (abfd->build_id != NULL)
39  return abfd->build_id;
40 
41  /* No build-id */
42  return NULL;
43 }
44 
45 /* See build-id.h. */
46 
47 int
48 build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check)
49 {
50  const struct bfd_build_id *found;
51  int retval = 0;
52 
53  found = build_id_bfd_get (abfd);
54 
55  if (found == NULL)
56  warning (_("File \"%s\" has no build-id, file skipped"),
57  bfd_get_filename (abfd));
58  else if (found->size != check_len
59  || memcmp (found->data, check, found->size) != 0)
60  warning (_("File \"%s\" has a different build-id, file skipped"),
61  bfd_get_filename (abfd));
62  else
63  retval = 1;
64 
65  return retval;
66 }
67 
68 /* See build-id.h. */
69 
70 bfd *
71 build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id)
72 {
73  char *link, *debugdir;
74  VEC (char_ptr) *debugdir_vec;
75  struct cleanup *back_to;
76  int ix;
77  bfd *abfd = NULL;
78 
79  /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
80  link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
81  + 2 * build_id_len + (sizeof ".debug" - 1) + 1);
82 
83  /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
84  cause "/.build-id/..." lookups. */
85 
86  debugdir_vec = dirnames_to_char_ptr_vec (debug_file_directory);
87  back_to = make_cleanup_free_char_ptr_vec (debugdir_vec);
88 
89  for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix)
90  {
91  size_t debugdir_len = strlen (debugdir);
92  const gdb_byte *data = build_id;
93  size_t size = build_id_len;
94  char *s;
95  char *filename = NULL;
96  struct cleanup *inner;
97 
98  memcpy (link, debugdir, debugdir_len);
99  s = &link[debugdir_len];
100  s += sprintf (s, "/.build-id/");
101  if (size > 0)
102  {
103  size--;
104  s += sprintf (s, "%02x", (unsigned) *data++);
105  }
106  if (size > 0)
107  *s++ = '/';
108  while (size-- > 0)
109  s += sprintf (s, "%02x", (unsigned) *data++);
110  strcpy (s, ".debug");
111 
112  /* lrealpath() is expensive even for the usually non-existent files. */
113  if (access (link, F_OK) == 0)
114  filename = lrealpath (link);
115 
116  if (filename == NULL)
117  continue;
118 
119  /* We expect to be silent on the non-existing files. */
120  inner = make_cleanup (xfree, filename);
121  abfd = gdb_bfd_open (filename, gnutarget, -1);
122  do_cleanups (inner);
123 
124  if (abfd == NULL)
125  continue;
126 
127  if (build_id_verify (abfd, build_id_len, build_id))
128  break;
129 
130  gdb_bfd_unref (abfd);
131  abfd = NULL;
132  }
133 
134  do_cleanups (back_to);
135  return abfd;
136 }
137 
138 /* See build-id.h. */
139 
140 char *
142 {
143  const struct bfd_build_id *build_id;
144 
145  build_id = build_id_bfd_get (objfile->obfd);
146  if (build_id != NULL)
147  {
148  bfd *abfd;
149 
150  abfd = build_id_to_debug_bfd (build_id->size, build_id->data);
151  /* Prevent looping on a stripped .debug file. */
152  if (abfd != NULL
153  && filename_cmp (bfd_get_filename (abfd),
154  objfile_name (objfile)) == 0)
155  {
156  warning (_("\"%s\": separate debug info file has no debug info"),
157  bfd_get_filename (abfd));
158  gdb_bfd_unref (abfd);
159  }
160  else if (abfd != NULL)
161  {
162  char *result = xstrdup (bfd_get_filename (abfd));
163 
164  gdb_bfd_unref (abfd);
165  return result;
166  }
167  }
168  return NULL;
169 }
bfd * obfd
Definition: objfiles.h:313
char * find_separate_debug_file_by_buildid(struct objfile *objfile)
Definition: build-id.c:141
void xfree(void *)
Definition: common-utils.c:97
void warning(const char *fmt,...)
Definition: errors.c:26
#define VEC(T)
Definition: vec.h:398
#define _(String)
Definition: gdb_locale.h:40
struct bfd * gdb_bfd_open(const char *name, const char *target, int fd)
Definition: gdb_bfd.c:320
char * char_ptr
Definition: gdb_vecs.h:25
char * debug_file_directory
Definition: symfile.c:1434
#define VEC_iterate(T, V, I, P)
Definition: vec.h:165
int build_id_verify(bfd *abfd, size_t check_len, const bfd_byte *check)
Definition: build-id.c:48
char * gnutarget
Definition: corefile.c:437
void gdb_bfd_unref(struct bfd *abfd)
Definition: gdb_bfd.c:475
struct cleanup * make_cleanup(make_cleanup_ftype *function, void *arg)
Definition: cleanups.c:117
struct cleanup * make_cleanup_free_char_ptr_vec(VEC(char_ptr)*char_ptr_vec)
Definition: utils.c:3215
const char * objfile_name(const struct objfile *objfile)
Definition: objfiles.c:1499
bfd_byte gdb_byte
Definition: common-types.h:38
const struct bfd_build_id * build_id_bfd_get(bfd *abfd)
Definition: build-id.c:33
static void check(BOOL ok, const char *file, int line)
Definition: windows-nat.c:284
bfd * build_id_to_debug_bfd(size_t build_id_len, const bfd_byte *build_id)
Definition: build-id.c:71
size_t size
Definition: go32-nat.c:242
void do_cleanups(struct cleanup *old_chain)
Definition: cleanups.c:175