1 /* Try to get an ELF or debug file through the debuginfod.
2 Copyright (C) 2019 Red Hat, Inc.
3 Copyright (C) 2022 Mark J. Wielaard <mark@klomp.org>
4 This file is part of elfutils.
5
6 This file is free software; you can redistribute it and/or modify
7 it under the terms of either
8
9 * the GNU Lesser General Public License as published by the Free
10 Software Foundation; either version 3 of the License, or (at
11 your option) any later version
12
13 or
14
15 * the GNU General Public License as published by the Free
16 Software Foundation; either version 2 of the License, or (at
17 your option) any later version
18
19 or both in parallel, as here.
20
21 elfutils is distributed in the hope that it will be useful, but
22 WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 General Public License for more details.
25
26 You should have received copies of the GNU General Public License and
27 the GNU Lesser General Public License along with this program. If
28 not, see <http://www.gnu.org/licenses/>. */
29
30 #ifdef HAVE_CONFIG_H
31 # include <config.h>
32 #endif
33
34 #include "libdwflP.h"
35
36 #ifdef ENABLE_LIBDEBUGINFOD
37
38 #include <pthread.h>
39 #include <dlfcn.h>
40
41 static __typeof__ (debuginfod_begin) *fp_debuginfod_begin;
42 static __typeof__ (debuginfod_find_executable) *fp_debuginfod_find_executable;
43 static __typeof__ (debuginfod_find_debuginfo) *fp_debuginfod_find_debuginfo;
44 static __typeof__ (debuginfod_end) *fp_debuginfod_end;
45
46 static void __libdwfl_debuginfod_init (void);
47
48 static pthread_once_t init_control = PTHREAD_ONCE_INIT;
49
50 /* NB: this is slightly thread-unsafe */
51
52 debuginfod_client *
dwfl_get_debuginfod_client(Dwfl * dwfl)53 dwfl_get_debuginfod_client (Dwfl *dwfl)
54 {
55 if (dwfl->debuginfod != NULL)
56 return dwfl->debuginfod;
57
58 pthread_once (&init_control, __libdwfl_debuginfod_init);
59
60 if (fp_debuginfod_begin != NULL)
61 {
62 dwfl->debuginfod = (*fp_debuginfod_begin) ();
63 return dwfl->debuginfod;
64 }
65
66 return NULL;
67 }
INTDEF(dwfl_get_debuginfod_client)68 INTDEF(dwfl_get_debuginfod_client)
69
70 int
71 __libdwfl_debuginfod_find_executable (Dwfl *dwfl,
72 const unsigned char *build_id_bits,
73 size_t build_id_len)
74 {
75 int fd = -1;
76 if (build_id_len > 0)
77 {
78 debuginfod_client *c = INTUSE (dwfl_get_debuginfod_client) (dwfl);
79 if (c != NULL)
80 fd = (*fp_debuginfod_find_executable) (c, build_id_bits,
81 build_id_len, NULL);
82 }
83
84 return fd;
85 }
86
87 int
__libdwfl_debuginfod_find_debuginfo(Dwfl * dwfl,const unsigned char * build_id_bits,size_t build_id_len)88 __libdwfl_debuginfod_find_debuginfo (Dwfl *dwfl,
89 const unsigned char *build_id_bits,
90 size_t build_id_len)
91 {
92 int fd = -1;
93 if (build_id_len > 0)
94 {
95 debuginfod_client *c = INTUSE (dwfl_get_debuginfod_client) (dwfl);
96 if (c != NULL)
97 fd = (*fp_debuginfod_find_debuginfo) (c, build_id_bits,
98 build_id_len, NULL);
99 }
100
101 return fd;
102 }
103
104 void
__libdwfl_debuginfod_end(debuginfod_client * c)105 __libdwfl_debuginfod_end (debuginfod_client *c)
106 {
107 if (c != NULL)
108 (*fp_debuginfod_end) (c);
109 }
110
111 /* Try to get the libdebuginfod library functions.
112 Only needs to be called once from dwfl_get_debuginfod_client. */
113 static void
__libdwfl_debuginfod_init(void)114 __libdwfl_debuginfod_init (void)
115 {
116 void *debuginfod_so = dlopen(DEBUGINFOD_SONAME, RTLD_LAZY);
117
118 if (debuginfod_so != NULL)
119 {
120 fp_debuginfod_begin = dlsym (debuginfod_so, "debuginfod_begin");
121 fp_debuginfod_find_executable = dlsym (debuginfod_so,
122 "debuginfod_find_executable");
123 fp_debuginfod_find_debuginfo = dlsym (debuginfod_so,
124 "debuginfod_find_debuginfo");
125 fp_debuginfod_end = dlsym (debuginfod_so, "debuginfod_end");
126
127 /* We either get them all, or we get none. */
128 if (fp_debuginfod_begin == NULL
129 || fp_debuginfod_find_executable == NULL
130 || fp_debuginfod_find_debuginfo == NULL
131 || fp_debuginfod_end == NULL)
132 {
133 fp_debuginfod_begin = NULL;
134 fp_debuginfod_find_executable = NULL;
135 fp_debuginfod_find_debuginfo = NULL;
136 fp_debuginfod_end = NULL;
137 dlclose (debuginfod_so);
138 }
139 }
140 }
141
142 #else // ENABLE_LIBDEBUGINFOD
143
144 debuginfod_client *
dwfl_get_debuginfod_client(Dwfl * dummy)145 dwfl_get_debuginfod_client (Dwfl *dummy __attribute__ ((unused)))
146 {
147 return NULL;
148 }
149
150 #endif // ENABLE_LIBDEBUGINFOD
151