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1 | /* |
2 | * Copyright (C) 2013 Paul Woegerer <paul_woegerer@mentor.com> | |
3 | * Copyright (C) 2015 Antoine Busque <abusque@efficios.com> | |
4 | * | |
5 | * This library is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU Lesser General Public | |
7 | * License as published by the Free Software Foundation; either | |
8 | * version 2.1 of the License, or (at your option) any later version. | |
9 | * | |
10 | * This library is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * Lesser General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU Lesser General Public | |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | ||
20 | #define _LGPL_SOURCE | |
21 | #define _GNU_SOURCE | |
22 | #include <link.h> | |
23 | ||
24 | #include <sys/types.h> | |
25 | #include <sys/stat.h> | |
26 | #include <unistd.h> | |
27 | #include <limits.h> | |
28 | #include <stdlib.h> | |
29 | #include <errno.h> | |
30 | #include <stdint.h> | |
31 | #include <stddef.h> | |
32 | #include <stdio.h> | |
33 | ||
34 | #include <usterr-signal-safe.h> | |
35 | #include "lttng-tracer-core.h" | |
36 | #include "lttng-ust-statedump.h" | |
37 | ||
38 | #define TRACEPOINT_DEFINE | |
39 | #define TRACEPOINT_CREATE_PROBES | |
40 | #define TP_SESSION_CHECK | |
41 | #include "lttng-ust-statedump-provider.h" | |
42 | ||
43 | struct dl_iterate_data { | |
44 | void *owner; | |
45 | int exec_found; | |
46 | }; | |
47 | ||
48 | struct soinfo_data { | |
49 | void *owner; | |
50 | void *base_addr_ptr; | |
51 | const char *resolved_path; | |
52 | int vdso; | |
53 | off_t size; | |
54 | time_t mtime; | |
55 | }; | |
56 | ||
57 | typedef void (*tracepoint_cb)(struct lttng_session *session, void *priv); | |
58 | ||
59 | /* | |
60 | * Trace statedump event into all sessions owned by the caller thread | |
61 | * for which statedump is pending. | |
62 | */ | |
63 | static | |
64 | int trace_statedump_event(tracepoint_cb tp_cb, void *owner, void *priv) | |
65 | { | |
66 | struct cds_list_head *sessionsp; | |
67 | struct lttng_session *session; | |
68 | ||
69 | /* | |
70 | * UST lock nests within dynamic loader lock. | |
71 | */ | |
72 | if (ust_lock()) { | |
73 | ust_unlock(); | |
74 | return 1; | |
75 | } | |
76 | ||
77 | sessionsp = _lttng_get_sessions(); | |
78 | cds_list_for_each_entry(session, sessionsp, node) { | |
79 | if (session->owner != owner) | |
80 | continue; | |
81 | if (!session->statedump_pending) | |
82 | continue; | |
83 | tp_cb(session, priv); | |
84 | } | |
85 | ust_unlock(); | |
86 | return 0; | |
87 | } | |
88 | ||
89 | static | |
90 | void trace_soinfo_cb(struct lttng_session *session, void *priv) | |
91 | { | |
92 | struct soinfo_data *so_data = (struct soinfo_data *) priv; | |
93 | ||
94 | tracepoint(lttng_ust_statedump, soinfo, | |
95 | session, so_data->base_addr_ptr, | |
96 | so_data->resolved_path, so_data->size, | |
97 | so_data->mtime); | |
98 | } | |
99 | ||
100 | static | |
101 | void trace_start_cb(struct lttng_session *session, void *priv) | |
102 | { | |
103 | tracepoint(lttng_ust_statedump, start, session); | |
104 | } | |
105 | ||
106 | static | |
107 | void trace_end_cb(struct lttng_session *session, void *priv) | |
108 | { | |
109 | tracepoint(lttng_ust_statedump, end, session); | |
110 | } | |
111 | ||
112 | static | |
113 | int trace_baddr(struct soinfo_data *so_data) | |
114 | { | |
115 | struct stat sostat; | |
116 | ||
117 | if (so_data->vdso || stat(so_data->resolved_path, &sostat)) { | |
118 | sostat.st_size = 0; | |
119 | sostat.st_mtime = -1; | |
120 | } | |
121 | ||
122 | so_data->size = sostat.st_size; | |
123 | so_data->mtime = sostat.st_mtime; | |
124 | ||
125 | return trace_statedump_event(trace_soinfo_cb, so_data->owner, so_data); | |
126 | } | |
127 | ||
128 | static | |
129 | int trace_statedump_start(void *owner) | |
130 | { | |
131 | return trace_statedump_event(trace_start_cb, owner, NULL); | |
132 | } | |
133 | ||
134 | static | |
135 | int trace_statedump_end(void *owner) | |
136 | { | |
137 | return trace_statedump_event(trace_end_cb, owner, NULL); | |
138 | } | |
139 | ||
140 | static | |
141 | int extract_soinfo_events(struct dl_phdr_info *info, size_t size, void *_data) | |
142 | { | |
143 | int j; | |
144 | struct dl_iterate_data *data = _data; | |
145 | ||
146 | for (j = 0; j < info->dlpi_phnum; j++) { | |
147 | struct soinfo_data so_data; | |
148 | char resolved_path[PATH_MAX]; | |
149 | void *base_addr_ptr; | |
150 | ||
151 | if (info->dlpi_phdr[j].p_type != PT_LOAD) | |
152 | continue; | |
153 | ||
154 | /* Calculate virtual memory address of the loadable segment */ | |
155 | base_addr_ptr = (void *) info->dlpi_addr + | |
156 | info->dlpi_phdr[j].p_vaddr; | |
157 | ||
158 | if ((info->dlpi_name == NULL || info->dlpi_name[0] == 0)) { | |
159 | /* | |
160 | * Only the first phdr without a dlpi_name | |
161 | * encountered is considered as the program | |
162 | * executable. The rest are vdsos. | |
163 | */ | |
164 | if (!data->exec_found) { | |
165 | ssize_t path_len; | |
166 | data->exec_found = 1; | |
167 | ||
168 | /* | |
169 | * Use /proc/self/exe to resolve the | |
170 | * executable's full path. | |
171 | */ | |
172 | path_len = readlink("/proc/self/exe", | |
173 | resolved_path, | |
174 | PATH_MAX - 1); | |
175 | if (path_len <= 0) | |
176 | break; | |
177 | ||
178 | resolved_path[path_len] = '\0'; | |
179 | so_data.vdso = 0; | |
180 | } else { | |
181 | snprintf(resolved_path, PATH_MAX - 1, "[vdso]"); | |
182 | so_data.vdso = 1; | |
183 | } | |
184 | } else { | |
185 | /* | |
186 | * For regular dl_phdr_info entries check if | |
187 | * the path to the SO really exists. If not, | |
188 | * treat as vdso and use dlpi_name as 'path'. | |
189 | */ | |
190 | if (!realpath(info->dlpi_name, resolved_path)) { | |
191 | snprintf(resolved_path, PATH_MAX - 1, "[%s]", | |
192 | info->dlpi_name); | |
193 | so_data.vdso = 1; | |
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194 | } else { |
195 | so_data.vdso = 0; | |
cf73e0fe AB |
196 | } |
197 | } | |
198 | ||
199 | so_data.owner = data->owner; | |
200 | so_data.base_addr_ptr = base_addr_ptr; | |
201 | so_data.resolved_path = resolved_path; | |
202 | return trace_baddr(&so_data); | |
203 | } | |
204 | ||
205 | return 0; | |
206 | } | |
207 | ||
208 | /* | |
209 | * Generate a statedump of base addresses of all shared objects loaded | |
210 | * by the traced application, as well as for the application's | |
211 | * executable itself. | |
212 | */ | |
213 | static | |
214 | int do_baddr_statedump(void *owner) | |
215 | { | |
216 | struct dl_iterate_data data; | |
217 | ||
218 | if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP")) | |
219 | return 0; | |
220 | ||
221 | data.owner = owner; | |
222 | data.exec_found = 0; | |
223 | /* | |
224 | * Iterate through the list of currently loaded shared objects and | |
225 | * generate events for loadable segments using | |
226 | * extract_soinfo_events. | |
227 | */ | |
228 | dl_iterate_phdr(extract_soinfo_events, &data); | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | /* | |
234 | * Generate a statedump of a given traced application. A statedump is | |
235 | * delimited by start and end events. For a given (process, session) | |
236 | * pair, begin/end events are serialized and will match. However, in a | |
237 | * session, statedumps from different processes may be | |
238 | * interleaved. The vpid context should be used to identify which | |
239 | * events belong to which process. | |
240 | */ | |
241 | int do_lttng_ust_statedump(void *owner) | |
242 | { | |
243 | trace_statedump_start(owner); | |
244 | do_baddr_statedump(owner); | |
245 | trace_statedump_end(owner); | |
246 | ||
247 | return 0; | |
248 | } | |
249 | ||
250 | void lttng_ust_statedump_init(void) | |
251 | { | |
252 | __tracepoints__init(); | |
253 | __tracepoints__ptrs_init(); | |
254 | __lttng_events_init__lttng_ust_statedump(); | |
255 | } | |
256 | ||
257 | void lttng_ust_statedump_destroy(void) | |
258 | { | |
259 | __lttng_events_exit__lttng_ust_statedump(); | |
260 | __tracepoints__ptrs_destroy(); | |
261 | __tracepoints__destroy(); | |
262 | } |