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52ad194e | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
663996b3 | 2 | /*** |
b012e921 | 3 | Copyright © 2010 ProFUSION embedded systems |
663996b3 MS |
4 | ***/ |
5 | ||
663996b3 | 6 | #include <errno.h> |
db2df898 MP |
7 | #include <signal.h> |
8 | #include <sys/wait.h> | |
663996b3 MS |
9 | #include <unistd.h> |
10 | ||
db2df898 | 11 | #include "alloc-util.h" |
5a920b42 | 12 | #include "def.h" |
2897b343 | 13 | #include "dirent-util.h" |
db2df898 | 14 | #include "fd-util.h" |
2897b343 | 15 | #include "format-util.h" |
db2df898 MP |
16 | #include "killall.h" |
17 | #include "parse-util.h" | |
e3bff60a | 18 | #include "process-util.h" |
db2df898 MP |
19 | #include "set.h" |
20 | #include "string-util.h" | |
e3bff60a | 21 | #include "terminal-util.h" |
db2df898 | 22 | #include "util.h" |
663996b3 | 23 | |
4c89c718 | 24 | static bool ignore_proc(pid_t pid, bool warn_rootfs) { |
663996b3 | 25 | _cleanup_fclose_ FILE *f = NULL; |
60f067b4 | 26 | const char *p; |
6e866b33 | 27 | char c = 0; |
663996b3 MS |
28 | uid_t uid; |
29 | int r; | |
30 | ||
31 | /* We are PID 1, let's not commit suicide */ | |
6e866b33 | 32 | if (pid <= 1) |
663996b3 MS |
33 | return true; |
34 | ||
6e866b33 MB |
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 | ||
663996b3 MS |
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 | ||
14228c0d MB |
48 | p = procfs_file_alloca(pid, "cmdline"); |
49 | f = fopen(p, "re"); | |
663996b3 MS |
50 | if (!f) |
51 | return true; /* not really, but has the desired effect */ | |
52 | ||
6e866b33 MB |
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); | |
663996b3 | 57 | |
2897b343 | 58 | /* Processes with argv[0][0] = '@' we ignore from the killing spree. |
663996b3 MS |
59 | * |
60 | * http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */ | |
2897b343 MP |
61 | if (c != '@') |
62 | return false; | |
4c89c718 | 63 | |
2897b343 MP |
64 | if (warn_rootfs && |
65 | pid_from_same_root_fs(pid) == 0) { | |
66 | ||
67 | _cleanup_free_ char *comm = NULL; | |
4c89c718 | 68 | |
6e866b33 | 69 | (void) get_process_comm(pid, &comm); |
4c89c718 | 70 | |
2897b343 MP |
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 | } | |
663996b3 | 76 | |
2897b343 | 77 | return true; |
663996b3 MS |
78 | } |
79 | ||
f2dec872 BR |
80 | static void log_children_no_yet_killed(Set *pids) { |
81 | _cleanup_free_ char *lst_child = NULL; | |
82 | Iterator i; | |
83 | void *p; | |
84 | ||
85 | SET_FOREACH(p, pids, i) { | |
86 | _cleanup_free_ char *s = NULL; | |
87 | ||
88 | if (get_process_comm(PTR_TO_PID(p), &s) < 0) | |
89 | (void) asprintf(&s, PID_FMT, PTR_TO_PID(p)); | |
90 | ||
91 | if (!strextend(&lst_child, ", ", s, NULL)) { | |
92 | log_oom(); | |
93 | return; | |
94 | } | |
95 | } | |
96 | ||
97 | if (isempty(lst_child)) | |
98 | return; | |
99 | ||
100 | log_warning("Waiting for process: %s", lst_child + 2); | |
101 | } | |
102 | ||
103 | static int wait_for_children(Set *pids, sigset_t *mask, usec_t timeout) { | |
104 | usec_t until, date_log_child, n; | |
663996b3 MS |
105 | |
106 | assert(mask); | |
107 | ||
f2dec872 BR |
108 | /* Return the number of children remaining in the pids set: That correspond to the number |
109 | * of processes still "alive" after the timeout */ | |
110 | ||
663996b3 | 111 | if (set_isempty(pids)) |
f2dec872 BR |
112 | return 0; |
113 | ||
114 | n = now(CLOCK_MONOTONIC); | |
115 | until = usec_add(n, timeout); | |
116 | date_log_child = usec_add(n, 10u * USEC_PER_SEC); | |
117 | if (date_log_child > until) | |
118 | date_log_child = usec_add(n, timeout / 2u); | |
663996b3 | 119 | |
663996b3 MS |
120 | for (;;) { |
121 | struct timespec ts; | |
122 | int k; | |
663996b3 MS |
123 | void *p; |
124 | Iterator i; | |
125 | ||
126 | /* First, let the kernel inform us about killed | |
127 | * children. Most processes will probably be our | |
128 | * children, but some are not (might be our | |
129 | * grandchildren instead...). */ | |
130 | for (;;) { | |
131 | pid_t pid; | |
132 | ||
133 | pid = waitpid(-1, NULL, WNOHANG); | |
134 | if (pid == 0) | |
135 | break; | |
136 | if (pid < 0) { | |
137 | if (errno == ECHILD) | |
138 | break; | |
139 | ||
f2dec872 | 140 | return log_error_errno(errno, "waitpid() failed: %m"); |
663996b3 MS |
141 | } |
142 | ||
d9dfd233 | 143 | (void) set_remove(pids, PID_TO_PTR(pid)); |
663996b3 MS |
144 | } |
145 | ||
146 | /* Now explicitly check who might be remaining, who | |
147 | * might not be our child. */ | |
148 | SET_FOREACH(p, pids, i) { | |
149 | ||
52ad194e MB |
150 | /* kill(pid, 0) sends no signal, but it tells |
151 | * us whether the process still exists. */ | |
152 | if (kill(PTR_TO_PID(p), 0) == 0) | |
663996b3 MS |
153 | continue; |
154 | ||
155 | if (errno != ESRCH) | |
156 | continue; | |
157 | ||
158 | set_remove(pids, p); | |
159 | } | |
160 | ||
161 | if (set_isempty(pids)) | |
f2dec872 | 162 | return 0; |
663996b3 MS |
163 | |
164 | n = now(CLOCK_MONOTONIC); | |
f2dec872 BR |
165 | if (date_log_child > 0 && n >= date_log_child) { |
166 | log_children_no_yet_killed(pids); | |
167 | /* Log the children not yet killed only once */ | |
168 | date_log_child = 0; | |
169 | } | |
170 | ||
663996b3 | 171 | if (n >= until) |
f2dec872 BR |
172 | return set_size(pids); |
173 | ||
174 | if (date_log_child > 0) | |
175 | timespec_store(&ts, MIN(until - n, date_log_child - n)); | |
176 | else | |
177 | timespec_store(&ts, until - n); | |
663996b3 | 178 | |
663996b3 MS |
179 | k = sigtimedwait(mask, NULL, &ts); |
180 | if (k != SIGCHLD) { | |
181 | ||
f2dec872 BR |
182 | if (k < 0 && errno != EAGAIN) |
183 | return log_error_errno(errno, "sigtimedwait() failed: %m"); | |
663996b3 MS |
184 | |
185 | if (k >= 0) | |
186 | log_warning("sigtimedwait() returned unexpected signal."); | |
187 | } | |
188 | } | |
189 | } | |
190 | ||
60f067b4 | 191 | static int killall(int sig, Set *pids, bool send_sighup) { |
663996b3 MS |
192 | _cleanup_closedir_ DIR *dir = NULL; |
193 | struct dirent *d; | |
f2dec872 BR |
194 | int n_killed = 0; |
195 | ||
196 | /* Send the specified signal to all remaining processes, if not excluded by ignore_proc(). | |
197 | * Returns the number of processes to which the specified signal was sent */ | |
663996b3 MS |
198 | |
199 | dir = opendir("/proc"); | |
200 | if (!dir) | |
f2dec872 | 201 | return log_warning_errno(errno, "opendir(/proc) failed: %m"); |
663996b3 | 202 | |
2897b343 | 203 | FOREACH_DIRENT_ALL(d, dir, break) { |
663996b3 | 204 | pid_t pid; |
86f210e9 | 205 | int r; |
663996b3 | 206 | |
f5e65279 | 207 | if (!IN_SET(d->d_type, DT_DIR, DT_UNKNOWN)) |
663996b3 MS |
208 | continue; |
209 | ||
210 | if (parse_pid(d->d_name, &pid) < 0) | |
211 | continue; | |
212 | ||
4c89c718 | 213 | if (ignore_proc(pid, sig == SIGKILL && !in_initrd())) |
663996b3 MS |
214 | continue; |
215 | ||
216 | if (sig == SIGKILL) { | |
e842803a | 217 | _cleanup_free_ char *s = NULL; |
663996b3 MS |
218 | |
219 | get_process_comm(pid, &s); | |
60f067b4 | 220 | log_notice("Sending SIGKILL to PID "PID_FMT" (%s).", pid, strna(s)); |
663996b3 MS |
221 | } |
222 | ||
223 | if (kill(pid, sig) >= 0) { | |
f2dec872 | 224 | n_killed++; |
86f210e9 | 225 | if (pids) { |
d9dfd233 | 226 | r = set_put(pids, PID_TO_PTR(pid)); |
86f210e9 MP |
227 | if (r < 0) |
228 | log_oom(); | |
229 | } | |
663996b3 | 230 | } else if (errno != ENOENT) |
f47781d8 | 231 | log_warning_errno(errno, "Could not kill %d: %m", pid); |
60f067b4 JS |
232 | |
233 | if (send_sighup) { | |
234 | /* Optionally, also send a SIGHUP signal, but | |
235 | only if the process has a controlling | |
236 | tty. This is useful to allow handling of | |
237 | shells which ignore SIGTERM but react to | |
238 | SIGHUP. We do not send this to processes that | |
239 | have no controlling TTY since we don't want to | |
240 | trigger reloads of daemon processes. Also we | |
241 | make sure to only send this after SIGTERM so | |
242 | that SIGTERM is always first in the queue. */ | |
243 | ||
60f067b4 | 244 | if (get_ctty_devnr(pid, NULL) >= 0) |
2897b343 MP |
245 | /* it's OK if the process is gone, just ignore the result */ |
246 | (void) kill(pid, SIGHUP); | |
60f067b4 | 247 | } |
663996b3 MS |
248 | } |
249 | ||
f2dec872 | 250 | return n_killed; |
663996b3 MS |
251 | } |
252 | ||
f2dec872 BR |
253 | int broadcast_signal(int sig, bool wait_for_exit, bool send_sighup, usec_t timeout) { |
254 | int n_children_left; | |
663996b3 | 255 | sigset_t mask, oldmask; |
e842803a | 256 | _cleanup_set_free_ Set *pids = NULL; |
663996b3 | 257 | |
f2dec872 BR |
258 | /* Send the specified signal to all remaining processes, if not excluded by ignore_proc(). |
259 | * Return: | |
260 | * - The number of processes still "alive" after the timeout (that should have been killed) | |
261 | * if the function needs to wait for the end of the processes (wait_for_exit). | |
262 | * - Otherwise, the number of processes to which the specified signal was sent */ | |
263 | ||
663996b3 | 264 | if (wait_for_exit) |
5eef597e | 265 | pids = set_new(NULL); |
663996b3 MS |
266 | |
267 | assert_se(sigemptyset(&mask) == 0); | |
268 | assert_se(sigaddset(&mask, SIGCHLD) == 0); | |
269 | assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0); | |
270 | ||
271 | if (kill(-1, SIGSTOP) < 0 && errno != ESRCH) | |
f47781d8 | 272 | log_warning_errno(errno, "kill(-1, SIGSTOP) failed: %m"); |
663996b3 | 273 | |
f2dec872 | 274 | n_children_left = killall(sig, pids, send_sighup); |
663996b3 MS |
275 | |
276 | if (kill(-1, SIGCONT) < 0 && errno != ESRCH) | |
f47781d8 | 277 | log_warning_errno(errno, "kill(-1, SIGCONT) failed: %m"); |
663996b3 | 278 | |
f2dec872 BR |
279 | if (wait_for_exit && n_children_left > 0) |
280 | n_children_left = wait_for_children(pids, &mask, timeout); | |
663996b3 MS |
281 | |
282 | assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0); | |
f2dec872 BR |
283 | |
284 | return n_children_left; | |
663996b3 | 285 | } |