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Commit | Line | Data |
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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
bd3fa1d2 | 2 | /*** |
96b2fb93 | 3 | Copyright © 2010 ProFUSION embedded systems |
bd3fa1d2 LP |
4 | ***/ |
5 | ||
bd3fa1d2 | 6 | #include <errno.h> |
07630cea LP |
7 | #include <signal.h> |
8 | #include <sys/wait.h> | |
aaf7eb81 | 9 | #include <unistd.h> |
bd3fa1d2 | 10 | |
b5efdb8a | 11 | #include "alloc-util.h" |
d4506129 | 12 | #include "def.h" |
8fb3f009 | 13 | #include "dirent-util.h" |
3ffd4af2 | 14 | #include "fd-util.h" |
f97b34a6 | 15 | #include "format-util.h" |
3ffd4af2 | 16 | #include "killall.h" |
6bedfcbb | 17 | #include "parse-util.h" |
0b452006 | 18 | #include "process-util.h" |
07630cea LP |
19 | #include "set.h" |
20 | #include "string-util.h" | |
288a74cc | 21 | #include "terminal-util.h" |
07630cea | 22 | #include "util.h" |
bd3fa1d2 | 23 | |
1359fffa | 24 | static bool ignore_proc(pid_t pid, bool warn_rootfs) { |
31885cd5 | 25 | _cleanup_fclose_ FILE *f = NULL; |
b68fa010 | 26 | const char *p; |
e45154c7 | 27 | char c = 0; |
bd3fa1d2 LP |
28 | uid_t uid; |
29 | int r; | |
30 | ||
31 | /* We are PID 1, let's not commit suicide */ | |
20ca2d10 | 32 | if (pid <= 1) |
bd3fa1d2 LP |
33 | return true; |
34 | ||
e45154c7 LP |
35 | /* Ignore kernel threads */ |
36 | r = is_kernel_thread(pid); | |
37 | if (r != 0) | |
38 | return true; /* also ignore processes where we can't determine this */ | |
39 | ||
bd3fa1d2 LP |
40 | r = get_process_uid(pid, &uid); |
41 | if (r < 0) | |
42 | return true; /* not really, but better safe than sorry */ | |
43 | ||
44 | /* Non-root processes otherwise are always subject to be killed */ | |
45 | if (uid != 0) | |
46 | return false; | |
47 | ||
5841bd80 ZJS |
48 | p = procfs_file_alloca(pid, "cmdline"); |
49 | f = fopen(p, "re"); | |
bd3fa1d2 LP |
50 | if (!f) |
51 | return true; /* not really, but has the desired effect */ | |
52 | ||
e45154c7 LP |
53 | /* Try to read the first character of the command line. If the cmdline is empty (which might be the case for |
54 | * kernel threads but potentially also other stuff), this line won't do anything, but we don't care much, as | |
55 | * actual kernel threads are already filtered out above. */ | |
56 | (void) fread(&c, 1, 1, f); | |
bd3fa1d2 | 57 | |
9e615117 | 58 | /* Processes with argv[0][0] = '@' we ignore from the killing spree. |
bd3fa1d2 | 59 | * |
0bdd282a | 60 | * https://systemd.io/ROOT_STORAGE_DAEMONS */ |
9e615117 ZJS |
61 | if (c != '@') |
62 | return false; | |
63 | ||
64 | if (warn_rootfs && | |
65 | pid_from_same_root_fs(pid) == 0) { | |
1359fffa | 66 | |
9e615117 | 67 | _cleanup_free_ char *comm = NULL; |
1359fffa | 68 | |
d3a94b3e | 69 | (void) get_process_comm(pid, &comm); |
1359fffa | 70 | |
9e615117 ZJS |
71 | log_notice("Process " PID_FMT " (%s) has been marked to be excluded from killing. It is " |
72 | "running from the root file system, and thus likely to block re-mounting of the " | |
73 | "root file system to read-only. Please consider moving it into an initrd file " | |
74 | "system instead.", pid, strna(comm)); | |
75 | } | |
bd3fa1d2 | 76 | |
9e615117 | 77 | return true; |
bd3fa1d2 LP |
78 | } |
79 | ||
2c32f4f4 | 80 | static void log_children_no_yet_killed(Set *pids) { |
2c32f4f4 | 81 | _cleanup_free_ char *lst_child = NULL; |
60cd3676 | 82 | void *p; |
2c32f4f4 | 83 | |
90e74a66 | 84 | SET_FOREACH(p, pids) { |
2c32f4f4 BR |
85 | _cleanup_free_ char *s = NULL; |
86 | ||
60cd3676 LP |
87 | if (get_process_comm(PTR_TO_PID(p), &s) < 0) |
88 | (void) asprintf(&s, PID_FMT, PTR_TO_PID(p)); | |
89 | ||
90 | if (!strextend(&lst_child, ", ", s, NULL)) { | |
91 | log_oom(); | |
92 | return; | |
2c32f4f4 BR |
93 | } |
94 | } | |
95 | ||
60cd3676 LP |
96 | if (isempty(lst_child)) |
97 | return; | |
98 | ||
99 | log_warning("Waiting for process: %s", lst_child + 2); | |
2c32f4f4 BR |
100 | } |
101 | ||
a012f9f7 | 102 | static int wait_for_children(Set *pids, sigset_t *mask, usec_t timeout) { |
60cd3676 | 103 | usec_t until, date_log_child, n; |
bd3fa1d2 LP |
104 | |
105 | assert(mask); | |
106 | ||
a012f9f7 BR |
107 | /* Return the number of children remaining in the pids set: That correspond to the number |
108 | * of processes still "alive" after the timeout */ | |
109 | ||
aaf7eb81 | 110 | if (set_isempty(pids)) |
a012f9f7 | 111 | return 0; |
aaf7eb81 | 112 | |
2c32f4f4 BR |
113 | n = now(CLOCK_MONOTONIC); |
114 | until = usec_add(n, timeout); | |
115 | date_log_child = usec_add(n, 10u * USEC_PER_SEC); | |
116 | if (date_log_child > until) | |
117 | date_log_child = usec_add(n, timeout / 2u); | |
118 | ||
bd3fa1d2 LP |
119 | for (;;) { |
120 | struct timespec ts; | |
121 | int k; | |
aaf7eb81 | 122 | void *p; |
bd3fa1d2 | 123 | |
aaf7eb81 LP |
124 | /* First, let the kernel inform us about killed |
125 | * children. Most processes will probably be our | |
126 | * children, but some are not (might be our | |
127 | * grandchildren instead...). */ | |
bd3fa1d2 | 128 | for (;;) { |
aaf7eb81 | 129 | pid_t pid; |
bd3fa1d2 | 130 | |
aaf7eb81 | 131 | pid = waitpid(-1, NULL, WNOHANG); |
bd3fa1d2 LP |
132 | if (pid == 0) |
133 | break; | |
aaf7eb81 LP |
134 | if (pid < 0) { |
135 | if (errno == ECHILD) | |
136 | break; | |
bd3fa1d2 | 137 | |
a012f9f7 | 138 | return log_error_errno(errno, "waitpid() failed: %m"); |
aaf7eb81 LP |
139 | } |
140 | ||
fea72cc0 | 141 | (void) set_remove(pids, PID_TO_PTR(pid)); |
aaf7eb81 | 142 | } |
bd3fa1d2 | 143 | |
aaf7eb81 LP |
144 | /* Now explicitly check who might be remaining, who |
145 | * might not be our child. */ | |
90e74a66 | 146 | SET_FOREACH(p, pids) { |
aaf7eb81 | 147 | |
3448a969 AJ |
148 | /* kill(pid, 0) sends no signal, but it tells |
149 | * us whether the process still exists. */ | |
150 | if (kill(PTR_TO_PID(p), 0) == 0) | |
aaf7eb81 LP |
151 | continue; |
152 | ||
153 | if (errno != ESRCH) | |
154 | continue; | |
155 | ||
156 | set_remove(pids, p); | |
bd3fa1d2 LP |
157 | } |
158 | ||
aaf7eb81 | 159 | if (set_isempty(pids)) |
a012f9f7 | 160 | return 0; |
aaf7eb81 | 161 | |
bd3fa1d2 | 162 | n = now(CLOCK_MONOTONIC); |
2c32f4f4 BR |
163 | if (date_log_child > 0 && n >= date_log_child) { |
164 | log_children_no_yet_killed(pids); | |
165 | /* Log the children not yet killed only once */ | |
166 | date_log_child = 0; | |
167 | } | |
168 | ||
bd3fa1d2 | 169 | if (n >= until) |
a012f9f7 | 170 | return set_size(pids); |
bd3fa1d2 | 171 | |
2c32f4f4 BR |
172 | if (date_log_child > 0) |
173 | timespec_store(&ts, MIN(until - n, date_log_child - n)); | |
174 | else | |
175 | timespec_store(&ts, until - n); | |
176 | ||
aaf7eb81 LP |
177 | k = sigtimedwait(mask, NULL, &ts); |
178 | if (k != SIGCHLD) { | |
bd3fa1d2 | 179 | |
a012f9f7 BR |
180 | if (k < 0 && errno != EAGAIN) |
181 | return log_error_errno(errno, "sigtimedwait() failed: %m"); | |
bd3fa1d2 LP |
182 | |
183 | if (k >= 0) | |
184 | log_warning("sigtimedwait() returned unexpected signal."); | |
185 | } | |
186 | } | |
187 | } | |
188 | ||
0bee65f0 | 189 | static int killall(int sig, Set *pids, bool send_sighup) { |
aaf7eb81 | 190 | _cleanup_closedir_ DIR *dir = NULL; |
bd3fa1d2 | 191 | struct dirent *d; |
a012f9f7 BR |
192 | int n_killed = 0; |
193 | ||
194 | /* Send the specified signal to all remaining processes, if not excluded by ignore_proc(). | |
195 | * Returns the number of processes to which the specified signal was sent */ | |
bd3fa1d2 LP |
196 | |
197 | dir = opendir("/proc"); | |
198 | if (!dir) | |
a012f9f7 | 199 | return log_warning_errno(errno, "opendir(/proc) failed: %m"); |
bd3fa1d2 | 200 | |
8fb3f009 | 201 | FOREACH_DIRENT_ALL(d, dir, break) { |
bd3fa1d2 | 202 | pid_t pid; |
60053efb | 203 | int r; |
bd3fa1d2 | 204 | |
ec2ce0c5 | 205 | if (!IN_SET(d->d_type, DT_DIR, DT_UNKNOWN)) |
bd3fa1d2 LP |
206 | continue; |
207 | ||
208 | if (parse_pid(d->d_name, &pid) < 0) | |
209 | continue; | |
210 | ||
1359fffa | 211 | if (ignore_proc(pid, sig == SIGKILL && !in_initrd())) |
bd3fa1d2 LP |
212 | continue; |
213 | ||
df758e98 | 214 | if (sig == SIGKILL) { |
3e09eb5c | 215 | _cleanup_free_ char *s = NULL; |
df758e98 | 216 | |
74d6421d | 217 | (void) get_process_comm(pid, &s); |
ccd06097 | 218 | log_notice("Sending SIGKILL to PID "PID_FMT" (%s).", pid, strna(s)); |
df758e98 KS |
219 | } |
220 | ||
aaf7eb81 | 221 | if (kill(pid, sig) >= 0) { |
a012f9f7 | 222 | n_killed++; |
60053efb | 223 | if (pids) { |
fea72cc0 | 224 | r = set_put(pids, PID_TO_PTR(pid)); |
60053efb TA |
225 | if (r < 0) |
226 | log_oom(); | |
227 | } | |
aaf7eb81 | 228 | } else if (errno != ENOENT) |
56f64d95 | 229 | log_warning_errno(errno, "Could not kill %d: %m", pid); |
0bee65f0 LP |
230 | |
231 | if (send_sighup) { | |
232 | /* Optionally, also send a SIGHUP signal, but | |
233 | only if the process has a controlling | |
234 | tty. This is useful to allow handling of | |
235 | shells which ignore SIGTERM but react to | |
236 | SIGHUP. We do not send this to processes that | |
237 | have no controlling TTY since we don't want to | |
238 | trigger reloads of daemon processes. Also we | |
239 | make sure to only send this after SIGTERM so | |
240 | that SIGTERM is always first in the queue. */ | |
241 | ||
0bee65f0 | 242 | if (get_ctty_devnr(pid, NULL) >= 0) |
5c5d9f26 ZJS |
243 | /* it's OK if the process is gone, just ignore the result */ |
244 | (void) kill(pid, SIGHUP); | |
0bee65f0 | 245 | } |
bd3fa1d2 LP |
246 | } |
247 | ||
a012f9f7 | 248 | return n_killed; |
bd3fa1d2 LP |
249 | } |
250 | ||
a012f9f7 BR |
251 | int broadcast_signal(int sig, bool wait_for_exit, bool send_sighup, usec_t timeout) { |
252 | int n_children_left; | |
bd3fa1d2 | 253 | sigset_t mask, oldmask; |
e1d75803 | 254 | _cleanup_set_free_ Set *pids = NULL; |
aaf7eb81 | 255 | |
763e7b5d BR |
256 | /* Send the specified signal to all remaining processes, if not excluded by ignore_proc(). |
257 | * Return: | |
258 | * - The number of processes still "alive" after the timeout (that should have been killed) | |
259 | * if the function needs to wait for the end of the processes (wait_for_exit). | |
260 | * - Otherwise, the number of processes to which the specified signal was sent */ | |
261 | ||
aaf7eb81 | 262 | if (wait_for_exit) |
d5099efc | 263 | pids = set_new(NULL); |
bd3fa1d2 LP |
264 | |
265 | assert_se(sigemptyset(&mask) == 0); | |
266 | assert_se(sigaddset(&mask, SIGCHLD) == 0); | |
267 | assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0); | |
268 | ||
269 | if (kill(-1, SIGSTOP) < 0 && errno != ESRCH) | |
56f64d95 | 270 | log_warning_errno(errno, "kill(-1, SIGSTOP) failed: %m"); |
bd3fa1d2 | 271 | |
a012f9f7 | 272 | n_children_left = killall(sig, pids, send_sighup); |
bd3fa1d2 LP |
273 | |
274 | if (kill(-1, SIGCONT) < 0 && errno != ESRCH) | |
56f64d95 | 275 | log_warning_errno(errno, "kill(-1, SIGCONT) failed: %m"); |
bd3fa1d2 | 276 | |
a012f9f7 BR |
277 | if (wait_for_exit && n_children_left > 0) |
278 | n_children_left = wait_for_children(pids, &mask, timeout); | |
aaf7eb81 LP |
279 | |
280 | assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0); | |
a012f9f7 BR |
281 | |
282 | return n_children_left; | |
bd3fa1d2 | 283 | } |