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13da1c97 | 1 | /* Linux-specific PROCFS manipulation routines. |
61baf725 | 2 | Copyright (C) 2009-2017 Free Software Foundation, Inc. |
13da1c97 LM |
3 | |
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
18 | ||
727605ca | 19 | #include "common-defs.h" |
13da1c97 | 20 | #include "linux-procfs.h" |
614c279d | 21 | #include "filestuff.h" |
8784d563 | 22 | #include <dirent.h> |
2db9a427 | 23 | #include <sys/stat.h> |
13da1c97 LM |
24 | |
25 | /* Return the TGID of LWPID from /proc/pid/status. Returns -1 if not | |
26 | found. */ | |
27 | ||
87b0bb13 | 28 | static int |
8784d563 | 29 | linux_proc_get_int (pid_t lwpid, const char *field, int warn) |
13da1c97 | 30 | { |
87b0bb13 | 31 | size_t field_len = strlen (field); |
13da1c97 LM |
32 | FILE *status_file; |
33 | char buf[100]; | |
87b0bb13 | 34 | int retval = -1; |
13da1c97 LM |
35 | |
36 | snprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid); | |
614c279d | 37 | status_file = gdb_fopen_cloexec (buf, "r"); |
87b0bb13 | 38 | if (status_file == NULL) |
13da1c97 | 39 | { |
8784d563 PA |
40 | if (warn) |
41 | warning (_("unable to open /proc file '%s'"), buf); | |
87b0bb13 | 42 | return -1; |
13da1c97 LM |
43 | } |
44 | ||
87b0bb13 JK |
45 | while (fgets (buf, sizeof (buf), status_file)) |
46 | if (strncmp (buf, field, field_len) == 0 && buf[field_len] == ':') | |
47 | { | |
48 | retval = strtol (&buf[field_len + 1], NULL, 10); | |
49 | break; | |
50 | } | |
51 | ||
52 | fclose (status_file); | |
53 | return retval; | |
13da1c97 | 54 | } |
644cebc9 | 55 | |
87b0bb13 JK |
56 | /* Return the TGID of LWPID from /proc/pid/status. Returns -1 if not |
57 | found. */ | |
644cebc9 PA |
58 | |
59 | int | |
87b0bb13 | 60 | linux_proc_get_tgid (pid_t lwpid) |
644cebc9 | 61 | { |
8784d563 | 62 | return linux_proc_get_int (lwpid, "Tgid", 1); |
87b0bb13 | 63 | } |
644cebc9 | 64 | |
87b0bb13 JK |
65 | /* See linux-procfs.h. */ |
66 | ||
67 | pid_t | |
8784d563 | 68 | linux_proc_get_tracerpid_nowarn (pid_t lwpid) |
87b0bb13 | 69 | { |
8784d563 | 70 | return linux_proc_get_int (lwpid, "TracerPid", 0); |
644cebc9 | 71 | } |
5f572dec | 72 | |
d617208b PA |
73 | /* Process states as discovered in the 'State' line of |
74 | /proc/PID/status. Not all possible states are represented here, | |
75 | only those that we care about. */ | |
76 | ||
77 | enum proc_state | |
78 | { | |
79 | /* Some state we don't handle. */ | |
80 | PROC_STATE_UNKNOWN, | |
81 | ||
82 | /* Stopped on a signal. */ | |
83 | PROC_STATE_STOPPED, | |
84 | ||
85 | /* Tracing stop. */ | |
86 | PROC_STATE_TRACING_STOP, | |
87 | ||
88 | /* Dead. */ | |
89 | PROC_STATE_DEAD, | |
90 | ||
91 | /* Zombie. */ | |
92 | PROC_STATE_ZOMBIE, | |
93 | }; | |
94 | ||
95 | /* Parse a PROC_STATE out of STATE, a buffer with the state found in | |
96 | the 'State:' line of /proc/PID/status. */ | |
97 | ||
98 | static enum proc_state | |
99 | parse_proc_status_state (const char *state) | |
100 | { | |
101 | state = skip_spaces_const (state); | |
102 | ||
103 | switch (state[0]) | |
104 | { | |
0e1a6a51 PA |
105 | case 't': |
106 | return PROC_STATE_TRACING_STOP; | |
d617208b | 107 | case 'T': |
0e1a6a51 | 108 | /* Before Linux 2.6.33, tracing stop used uppercase T. */ |
d617208b PA |
109 | if (strcmp (state, "T (tracing stop)") == 0) |
110 | return PROC_STATE_TRACING_STOP; | |
111 | else | |
112 | return PROC_STATE_STOPPED; | |
113 | case 'X': | |
114 | return PROC_STATE_DEAD; | |
115 | case 'Z': | |
116 | return PROC_STATE_ZOMBIE; | |
117 | } | |
118 | ||
119 | return PROC_STATE_UNKNOWN; | |
120 | } | |
121 | ||
122 | ||
123 | /* Fill in STATE, a buffer with BUFFER_SIZE bytes with the 'State' | |
8784d563 PA |
124 | line of /proc/PID/status. Returns -1 on failure to open the /proc |
125 | file, 1 if the line is found, and 0 if not found. If WARN, warn on | |
126 | failure to open the /proc file. */ | |
5f572dec | 127 | |
87b0bb13 | 128 | static int |
d617208b | 129 | linux_proc_pid_get_state (pid_t pid, int warn, enum proc_state *state) |
5f572dec | 130 | { |
5f572dec | 131 | FILE *procfile; |
5f572dec | 132 | int have_state; |
d617208b | 133 | char buffer[100]; |
5f572dec | 134 | |
d617208b | 135 | xsnprintf (buffer, sizeof (buffer), "/proc/%d/status", (int) pid); |
614c279d | 136 | procfile = gdb_fopen_cloexec (buffer, "r"); |
5f572dec JK |
137 | if (procfile == NULL) |
138 | { | |
8784d563 PA |
139 | if (warn) |
140 | warning (_("unable to open /proc file '%s'"), buffer); | |
141 | return -1; | |
5f572dec JK |
142 | } |
143 | ||
144 | have_state = 0; | |
d617208b | 145 | while (fgets (buffer, sizeof (buffer), procfile) != NULL) |
61012eef | 146 | if (startswith (buffer, "State:")) |
5f572dec JK |
147 | { |
148 | have_state = 1; | |
d617208b | 149 | *state = parse_proc_status_state (buffer + sizeof ("State:") - 1); |
5f572dec JK |
150 | break; |
151 | } | |
5f572dec | 152 | fclose (procfile); |
8784d563 PA |
153 | return have_state; |
154 | } | |
155 | ||
156 | /* See linux-procfs.h declaration. */ | |
157 | ||
158 | int | |
159 | linux_proc_pid_is_gone (pid_t pid) | |
160 | { | |
8784d563 | 161 | int have_state; |
d617208b | 162 | enum proc_state state; |
8784d563 | 163 | |
d617208b | 164 | have_state = linux_proc_pid_get_state (pid, 0, &state); |
8784d563 PA |
165 | if (have_state < 0) |
166 | { | |
167 | /* If we can't open the status file, assume the thread has | |
168 | disappeared. */ | |
169 | return 1; | |
170 | } | |
171 | else if (have_state == 0) | |
172 | { | |
173 | /* No "State:" line, assume thread is alive. */ | |
174 | return 0; | |
175 | } | |
176 | else | |
d617208b | 177 | return (state == PROC_STATE_ZOMBIE || state == PROC_STATE_DEAD); |
8784d563 PA |
178 | } |
179 | ||
180 | /* Return non-zero if 'State' of /proc/PID/status contains STATE. If | |
181 | WARN, warn on failure to open the /proc file. */ | |
182 | ||
183 | static int | |
d617208b | 184 | linux_proc_pid_has_state (pid_t pid, enum proc_state state, int warn) |
8784d563 | 185 | { |
8784d563 | 186 | int have_state; |
d617208b | 187 | enum proc_state cur_state; |
8784d563 | 188 | |
d617208b PA |
189 | have_state = linux_proc_pid_get_state (pid, warn, &cur_state); |
190 | return (have_state > 0 && cur_state == state); | |
5f572dec | 191 | } |
87b0bb13 JK |
192 | |
193 | /* Detect `T (stopped)' in `/proc/PID/status'. | |
194 | Other states including `T (tracing stop)' are reported as false. */ | |
195 | ||
196 | int | |
197 | linux_proc_pid_is_stopped (pid_t pid) | |
198 | { | |
d617208b | 199 | return linux_proc_pid_has_state (pid, PROC_STATE_STOPPED, 1); |
8784d563 PA |
200 | } |
201 | ||
d617208b | 202 | /* Detect `t (tracing stop)' in `/proc/PID/status'. |
23f238d3 PA |
203 | Other states including `T (stopped)' are reported as false. */ |
204 | ||
205 | int | |
206 | linux_proc_pid_is_trace_stopped_nowarn (pid_t pid) | |
207 | { | |
d617208b | 208 | return linux_proc_pid_has_state (pid, PROC_STATE_TRACING_STOP, 1); |
23f238d3 PA |
209 | } |
210 | ||
8784d563 PA |
211 | /* Return non-zero if PID is a zombie. If WARN, warn on failure to |
212 | open the /proc file. */ | |
213 | ||
214 | static int | |
215 | linux_proc_pid_is_zombie_maybe_warn (pid_t pid, int warn) | |
216 | { | |
d617208b | 217 | return linux_proc_pid_has_state (pid, PROC_STATE_ZOMBIE, warn); |
8784d563 PA |
218 | } |
219 | ||
220 | /* See linux-procfs.h declaration. */ | |
221 | ||
222 | int | |
223 | linux_proc_pid_is_zombie_nowarn (pid_t pid) | |
224 | { | |
225 | return linux_proc_pid_is_zombie_maybe_warn (pid, 0); | |
87b0bb13 JK |
226 | } |
227 | ||
228 | /* See linux-procfs.h declaration. */ | |
229 | ||
230 | int | |
231 | linux_proc_pid_is_zombie (pid_t pid) | |
232 | { | |
8784d563 | 233 | return linux_proc_pid_is_zombie_maybe_warn (pid, 1); |
87b0bb13 | 234 | } |
015de688 | 235 | |
8784d563 PA |
236 | /* See linux-procfs.h. */ |
237 | ||
79efa585 SM |
238 | const char * |
239 | linux_proc_tid_get_name (ptid_t ptid) | |
240 | { | |
241 | #define TASK_COMM_LEN 16 /* As defined in the kernel's sched.h. */ | |
242 | ||
243 | static char comm_buf[TASK_COMM_LEN]; | |
244 | char comm_path[100]; | |
245 | FILE *comm_file; | |
246 | const char *comm_val; | |
247 | pid_t pid = ptid_get_pid (ptid); | |
248 | pid_t tid = ptid_lwp_p (ptid) ? ptid_get_lwp (ptid) : ptid_get_pid (ptid); | |
249 | ||
250 | xsnprintf (comm_path, sizeof (comm_path), | |
251 | "/proc/%ld/task/%ld/comm", (long) pid, (long) tid); | |
252 | ||
253 | comm_file = gdb_fopen_cloexec (comm_path, "r"); | |
254 | if (comm_file == NULL) | |
255 | return NULL; | |
256 | ||
257 | comm_val = fgets (comm_buf, sizeof (comm_buf), comm_file); | |
258 | fclose (comm_file); | |
259 | ||
260 | if (comm_val != NULL) | |
261 | { | |
262 | int i; | |
263 | ||
264 | /* Make sure there is no newline at the end. */ | |
265 | for (i = 0; i < sizeof (comm_buf); i++) | |
266 | { | |
267 | if (comm_buf[i] == '\n') | |
268 | { | |
269 | comm_buf[i] = '\0'; | |
270 | break; | |
271 | } | |
272 | } | |
273 | } | |
274 | ||
275 | return comm_val; | |
276 | } | |
277 | ||
278 | /* See linux-procfs.h. */ | |
279 | ||
8784d563 PA |
280 | void |
281 | linux_proc_attach_tgid_threads (pid_t pid, | |
282 | linux_proc_attach_lwp_func attach_lwp) | |
283 | { | |
284 | DIR *dir; | |
285 | char pathname[128]; | |
286 | int new_threads_found; | |
287 | int iterations; | |
288 | ||
289 | if (linux_proc_get_tgid (pid) != pid) | |
290 | return; | |
291 | ||
292 | xsnprintf (pathname, sizeof (pathname), "/proc/%ld/task", (long) pid); | |
293 | dir = opendir (pathname); | |
294 | if (dir == NULL) | |
295 | { | |
92fc2e69 | 296 | warning (_("Could not open /proc/%ld/task."), (long) pid); |
8784d563 PA |
297 | return; |
298 | } | |
299 | ||
300 | /* Scan the task list for existing threads. While we go through the | |
301 | threads, new threads may be spawned. Cycle through the list of | |
302 | threads until we have done two iterations without finding new | |
303 | threads. */ | |
304 | for (iterations = 0; iterations < 2; iterations++) | |
305 | { | |
306 | struct dirent *dp; | |
307 | ||
308 | new_threads_found = 0; | |
309 | while ((dp = readdir (dir)) != NULL) | |
310 | { | |
311 | unsigned long lwp; | |
312 | ||
313 | /* Fetch one lwp. */ | |
314 | lwp = strtoul (dp->d_name, NULL, 10); | |
315 | if (lwp != 0) | |
316 | { | |
317 | ptid_t ptid = ptid_build (pid, lwp, 0); | |
318 | ||
319 | if (attach_lwp (ptid)) | |
320 | new_threads_found = 1; | |
321 | } | |
322 | } | |
323 | ||
324 | if (new_threads_found) | |
325 | { | |
326 | /* Start over. */ | |
327 | iterations = -1; | |
328 | } | |
329 | ||
330 | rewinddir (dir); | |
331 | } | |
332 | ||
333 | closedir (dir); | |
334 | } | |
2db9a427 PA |
335 | |
336 | /* See linux-procfs.h. */ | |
337 | ||
338 | int | |
339 | linux_proc_task_list_dir_exists (pid_t pid) | |
340 | { | |
341 | char pathname[128]; | |
342 | struct stat buf; | |
343 | ||
344 | xsnprintf (pathname, sizeof (pathname), "/proc/%ld/task", (long) pid); | |
345 | return (stat (pathname, &buf) == 0); | |
346 | } | |
e0d86d2c GB |
347 | |
348 | /* See linux-procfs.h. */ | |
349 | ||
350 | char * | |
351 | linux_proc_pid_to_exec_file (int pid) | |
352 | { | |
353 | static char buf[PATH_MAX]; | |
354 | char name[PATH_MAX]; | |
355 | ssize_t len; | |
356 | ||
357 | xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); | |
358 | len = readlink (name, buf, PATH_MAX - 1); | |
359 | if (len <= 0) | |
360 | strcpy (buf, name); | |
361 | else | |
362 | buf[len] = '\0'; | |
363 | ||
364 | return buf; | |
365 | } |