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b13d93c2 PW |
1 | /* |
2 | * Copyright (C) 2013 Paul Woegerer <paul_woegerer@mentor.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
6 | * License as published by the Free Software Foundation; either | |
7 | * version 2.1 of the License, or (at your option) any later version. | |
8 | * | |
9 | * This library is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
15 | * License along with this library; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
5aed31fc | 19 | #define _LGPL_SOURCE |
b13d93c2 | 20 | #define _GNU_SOURCE |
b13d93c2 PW |
21 | #include <link.h> |
22 | ||
23 | #include <sys/types.h> | |
24 | #include <sys/stat.h> | |
b13d93c2 PW |
25 | #include <unistd.h> |
26 | #include <limits.h> | |
27 | #include <stdlib.h> | |
28 | #include <errno.h> | |
29 | #include <stdint.h> | |
30 | #include <stddef.h> | |
31 | #include <stdio.h> | |
b13d93c2 | 32 | |
9e166115 MD |
33 | #include <usterr-signal-safe.h> |
34 | #include "lttng-tracer-core.h" | |
13436238 PW |
35 | #include "lttng-ust-baddr.h" |
36 | ||
b13d93c2 | 37 | #define TRACEPOINT_DEFINE |
f0cc794d MD |
38 | #define TRACEPOINT_CREATE_PROBES |
39 | #define TP_SESSION_CHECK | |
95c25348 | 40 | #include "ust_baddr_statedump.h" |
b13d93c2 | 41 | |
5aed31fc MD |
42 | struct extract_data { |
43 | void *owner; | |
44 | void *exec_baddr; /* executable base address */ | |
45 | }; | |
46 | ||
47 | /* | |
48 | * Trace baddr into all sessions for which statedump is pending owned by | |
49 | * the caller thread. | |
50 | */ | |
37dddb65 | 51 | static |
5aed31fc MD |
52 | int trace_baddr(void *base_addr_ptr, |
53 | const char *resolved_path, | |
54 | int vdso, | |
55 | void *owner) | |
95c25348 | 56 | { |
37dddb65 | 57 | struct cds_list_head *sessionsp; |
5aed31fc MD |
58 | struct lttng_session *session; |
59 | struct stat sostat; | |
60 | ||
61 | if (vdso || stat(resolved_path, &sostat)) { | |
62 | sostat.st_size = 0; | |
63 | sostat.st_mtime = -1; | |
64 | } | |
65 | /* | |
66 | * UST lock nests within dynamic loader lock. | |
67 | */ | |
68 | if (ust_lock()) { | |
69 | /* | |
70 | * Stop iteration on headers if need to exit. | |
71 | */ | |
72 | ust_unlock(); | |
73 | return 1; | |
74 | } | |
75 | ||
76 | sessionsp = _lttng_get_sessions(); | |
77 | cds_list_for_each_entry(session, sessionsp, node) { | |
78 | if (session->owner != owner) | |
79 | continue; | |
80 | if (!session->statedump_pending) | |
81 | continue; | |
82 | tracepoint(ust_baddr_statedump, soinfo, | |
83 | session, base_addr_ptr, | |
84 | resolved_path, sostat.st_size, | |
85 | sostat.st_mtime); | |
86 | } | |
87 | ust_unlock(); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | static | |
92 | int extract_soinfo_events(struct dl_phdr_info *info, size_t size, void *_data) | |
93 | { | |
94 | int j; | |
95 | struct extract_data *data = _data; | |
96 | void *owner = data->owner; | |
37dddb65 | 97 | |
95c25348 PW |
98 | for (j = 0; j < info->dlpi_phnum; j++) { |
99 | char resolved_path[PATH_MAX]; | |
95c25348 | 100 | void *base_addr_ptr; |
5aed31fc | 101 | int vdso = 0; |
95c25348 PW |
102 | |
103 | if (info->dlpi_phdr[j].p_type != PT_LOAD) | |
104 | continue; | |
105 | ||
106 | /* Calculate virtual memory address of the loadable segment */ | |
107 | base_addr_ptr = (void *) info->dlpi_addr | |
108 | + info->dlpi_phdr[j].p_vaddr; | |
109 | ||
95c25348 | 110 | if ((info->dlpi_name == NULL || info->dlpi_name[0] == 0) |
5aed31fc MD |
111 | && !data->exec_baddr) { |
112 | /* | |
113 | * Only the first phdr encountered is considered | |
114 | * as the program executable. The following | |
115 | * could be e.g. vdso. Don't mistakenly dump | |
116 | * them as being the program executable. | |
117 | */ | |
118 | data->exec_baddr = base_addr_ptr; | |
95c25348 | 119 | /* |
5aed31fc MD |
120 | * Deal with program executable outside of phdr |
121 | * iteration. | |
95c25348 | 122 | */ |
5aed31fc MD |
123 | break; |
124 | } | |
125 | if (info->dlpi_name == NULL || info->dlpi_name[0] == 0) { | |
126 | /* Found vDSO. */ | |
127 | snprintf(resolved_path, PATH_MAX - 1, "[vdso]"); | |
128 | vdso = 1; | |
95c25348 PW |
129 | } else { |
130 | /* | |
131 | * For regular dl_phdr_info entries we have to check if | |
5aed31fc | 132 | * the path to the shared object really exists. |
95c25348 PW |
133 | */ |
134 | if (!realpath(info->dlpi_name, resolved_path)) { | |
5aed31fc | 135 | /* Path unknown, put the 'path' into brackets */ |
95c25348 | 136 | snprintf(resolved_path, PATH_MAX - 1, "[%s]", |
5aed31fc MD |
137 | info->dlpi_name); |
138 | vdso = 1; | |
95c25348 PW |
139 | } |
140 | } | |
5aed31fc | 141 | if (trace_baddr(base_addr_ptr, resolved_path, vdso, owner)) { |
3327ac33 MD |
142 | return 1; |
143 | } | |
95c25348 PW |
144 | /* |
145 | * We are only interested in the base address (lowest virtual | |
146 | * address associated with the memory image), skip the rest | |
147 | */ | |
148 | break; | |
149 | } | |
150 | return 0; | |
151 | } | |
152 | ||
5aed31fc MD |
153 | static |
154 | void dump_exec_baddr(struct extract_data *data) | |
155 | { | |
156 | void *owner = data->owner; | |
5aed31fc | 157 | void *base_addr_ptr; |
6d0c2f84 PW |
158 | char exe_path[PATH_MAX]; |
159 | ssize_t exe_len; | |
5aed31fc MD |
160 | |
161 | base_addr_ptr = data->exec_baddr; | |
162 | if (!base_addr_ptr) | |
163 | return; | |
164 | /* | |
6d0c2f84 PW |
165 | * We have to use /proc/self/exe to determine the executable full |
166 | * path. | |
5aed31fc | 167 | */ |
6d0c2f84 PW |
168 | exe_len = readlink("/proc/self/exe", exe_path, sizeof(exe_path) - 1); |
169 | if (exe_len <= 0) | |
5aed31fc | 170 | return; |
6d0c2f84 PW |
171 | exe_path[exe_len] = '\0'; |
172 | trace_baddr(base_addr_ptr, exe_path, 0, owner); | |
5aed31fc MD |
173 | } |
174 | ||
37dddb65 | 175 | int lttng_ust_baddr_statedump(void *owner) |
95c25348 | 176 | { |
5aed31fc MD |
177 | struct extract_data data; |
178 | ||
ca7643d6 PW |
179 | if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP")) |
180 | return 0; | |
5aed31fc MD |
181 | |
182 | data.owner = owner; | |
183 | data.exec_baddr = NULL; | |
95c25348 PW |
184 | /* |
185 | * Iterate through the list of currently loaded shared objects and | |
37dddb65 MD |
186 | * generate events for loadable segments using |
187 | * extract_soinfo_events. | |
95c25348 | 188 | */ |
5aed31fc MD |
189 | dl_iterate_phdr(extract_soinfo_events, &data); |
190 | /* | |
191 | * We cannot call dladdr() from within phdr iteration, without | |
192 | * causing constructor vs dynamic loader vs multithread internal | |
193 | * deadlocks, so dump the executable outside of the phdr | |
194 | * iteration. | |
195 | */ | |
196 | dump_exec_baddr(&data); | |
95c25348 PW |
197 | return 0; |
198 | } | |
bd703713 PW |
199 | |
200 | void lttng_ust_baddr_statedump_init(void) | |
201 | { | |
202 | __tracepoints__init(); | |
203 | __tracepoints__ptrs_init(); | |
f0cc794d | 204 | __lttng_events_init__ust_baddr_statedump(); |
bd703713 PW |
205 | } |
206 | ||
207 | void lttng_ust_baddr_statedump_destroy(void) | |
208 | { | |
f0cc794d | 209 | __lttng_events_exit__ust_baddr_statedump(); |
bd703713 PW |
210 | __tracepoints__ptrs_destroy(); |
211 | __tracepoints__destroy(); | |
212 | } |