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663996b3 MS |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 ProFUSION embedded systems | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
663996b3 | 22 | #include <errno.h> |
db2df898 MP |
23 | #include <signal.h> |
24 | #include <sys/wait.h> | |
663996b3 MS |
25 | #include <unistd.h> |
26 | ||
db2df898 MP |
27 | #include "alloc-util.h" |
28 | #include "fd-util.h" | |
e3bff60a | 29 | #include "formats-util.h" |
db2df898 MP |
30 | #include "killall.h" |
31 | #include "parse-util.h" | |
e3bff60a | 32 | #include "process-util.h" |
db2df898 MP |
33 | #include "set.h" |
34 | #include "string-util.h" | |
e3bff60a | 35 | #include "terminal-util.h" |
db2df898 | 36 | #include "util.h" |
663996b3 MS |
37 | |
38 | #define TIMEOUT_USEC (10 * USEC_PER_SEC) | |
39 | ||
40 | static bool ignore_proc(pid_t pid) { | |
41 | _cleanup_fclose_ FILE *f = NULL; | |
60f067b4 JS |
42 | char c; |
43 | const char *p; | |
663996b3 MS |
44 | size_t count; |
45 | uid_t uid; | |
46 | int r; | |
47 | ||
48 | /* We are PID 1, let's not commit suicide */ | |
49 | if (pid == 1) | |
50 | return true; | |
51 | ||
52 | r = get_process_uid(pid, &uid); | |
53 | if (r < 0) | |
54 | return true; /* not really, but better safe than sorry */ | |
55 | ||
56 | /* Non-root processes otherwise are always subject to be killed */ | |
57 | if (uid != 0) | |
58 | return false; | |
59 | ||
14228c0d MB |
60 | p = procfs_file_alloca(pid, "cmdline"); |
61 | f = fopen(p, "re"); | |
663996b3 MS |
62 | if (!f) |
63 | return true; /* not really, but has the desired effect */ | |
64 | ||
65 | count = fread(&c, 1, 1, f); | |
66 | ||
67 | /* Kernel threads have an empty cmdline */ | |
68 | if (count <= 0) | |
69 | return true; | |
70 | ||
71 | /* Processes with argv[0][0] = '@' we ignore from the killing | |
72 | * spree. | |
73 | * | |
74 | * http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */ | |
75 | if (count == 1 && c == '@') | |
76 | return true; | |
77 | ||
78 | return false; | |
79 | } | |
80 | ||
81 | static void wait_for_children(Set *pids, sigset_t *mask) { | |
82 | usec_t until; | |
83 | ||
84 | assert(mask); | |
85 | ||
86 | if (set_isempty(pids)) | |
87 | return; | |
88 | ||
89 | until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC; | |
90 | for (;;) { | |
91 | struct timespec ts; | |
92 | int k; | |
93 | usec_t n; | |
94 | void *p; | |
95 | Iterator i; | |
96 | ||
97 | /* First, let the kernel inform us about killed | |
98 | * children. Most processes will probably be our | |
99 | * children, but some are not (might be our | |
100 | * grandchildren instead...). */ | |
101 | for (;;) { | |
102 | pid_t pid; | |
103 | ||
104 | pid = waitpid(-1, NULL, WNOHANG); | |
105 | if (pid == 0) | |
106 | break; | |
107 | if (pid < 0) { | |
108 | if (errno == ECHILD) | |
109 | break; | |
110 | ||
f47781d8 | 111 | log_error_errno(errno, "waitpid() failed: %m"); |
663996b3 MS |
112 | return; |
113 | } | |
114 | ||
d9dfd233 | 115 | (void) set_remove(pids, PID_TO_PTR(pid)); |
663996b3 MS |
116 | } |
117 | ||
118 | /* Now explicitly check who might be remaining, who | |
119 | * might not be our child. */ | |
120 | SET_FOREACH(p, pids, i) { | |
121 | ||
122 | /* We misuse getpgid as a check whether a | |
123 | * process still exists. */ | |
d9dfd233 | 124 | if (getpgid(PTR_TO_PID(p)) >= 0) |
663996b3 MS |
125 | continue; |
126 | ||
127 | if (errno != ESRCH) | |
128 | continue; | |
129 | ||
130 | set_remove(pids, p); | |
131 | } | |
132 | ||
133 | if (set_isempty(pids)) | |
134 | return; | |
135 | ||
136 | n = now(CLOCK_MONOTONIC); | |
137 | if (n >= until) | |
138 | return; | |
139 | ||
140 | timespec_store(&ts, until - n); | |
141 | k = sigtimedwait(mask, NULL, &ts); | |
142 | if (k != SIGCHLD) { | |
143 | ||
144 | if (k < 0 && errno != EAGAIN) { | |
f47781d8 | 145 | log_error_errno(errno, "sigtimedwait() failed: %m"); |
663996b3 MS |
146 | return; |
147 | } | |
148 | ||
149 | if (k >= 0) | |
150 | log_warning("sigtimedwait() returned unexpected signal."); | |
151 | } | |
152 | } | |
153 | } | |
154 | ||
60f067b4 | 155 | static int killall(int sig, Set *pids, bool send_sighup) { |
663996b3 MS |
156 | _cleanup_closedir_ DIR *dir = NULL; |
157 | struct dirent *d; | |
158 | ||
159 | dir = opendir("/proc"); | |
160 | if (!dir) | |
161 | return -errno; | |
162 | ||
163 | while ((d = readdir(dir))) { | |
164 | pid_t pid; | |
86f210e9 | 165 | int r; |
663996b3 MS |
166 | |
167 | if (d->d_type != DT_DIR && | |
168 | d->d_type != DT_UNKNOWN) | |
169 | continue; | |
170 | ||
171 | if (parse_pid(d->d_name, &pid) < 0) | |
172 | continue; | |
173 | ||
174 | if (ignore_proc(pid)) | |
175 | continue; | |
176 | ||
177 | if (sig == SIGKILL) { | |
e842803a | 178 | _cleanup_free_ char *s = NULL; |
663996b3 MS |
179 | |
180 | get_process_comm(pid, &s); | |
60f067b4 | 181 | log_notice("Sending SIGKILL to PID "PID_FMT" (%s).", pid, strna(s)); |
663996b3 MS |
182 | } |
183 | ||
184 | if (kill(pid, sig) >= 0) { | |
86f210e9 | 185 | if (pids) { |
d9dfd233 | 186 | r = set_put(pids, PID_TO_PTR(pid)); |
86f210e9 MP |
187 | if (r < 0) |
188 | log_oom(); | |
189 | } | |
663996b3 | 190 | } else if (errno != ENOENT) |
f47781d8 | 191 | log_warning_errno(errno, "Could not kill %d: %m", pid); |
60f067b4 JS |
192 | |
193 | if (send_sighup) { | |
194 | /* Optionally, also send a SIGHUP signal, but | |
195 | only if the process has a controlling | |
196 | tty. This is useful to allow handling of | |
197 | shells which ignore SIGTERM but react to | |
198 | SIGHUP. We do not send this to processes that | |
199 | have no controlling TTY since we don't want to | |
200 | trigger reloads of daemon processes. Also we | |
201 | make sure to only send this after SIGTERM so | |
202 | that SIGTERM is always first in the queue. */ | |
203 | ||
204 | ||
205 | if (get_ctty_devnr(pid, NULL) >= 0) | |
206 | kill(pid, SIGHUP); | |
207 | } | |
663996b3 MS |
208 | } |
209 | ||
210 | return set_size(pids); | |
211 | } | |
212 | ||
60f067b4 | 213 | void broadcast_signal(int sig, bool wait_for_exit, bool send_sighup) { |
663996b3 | 214 | sigset_t mask, oldmask; |
e842803a | 215 | _cleanup_set_free_ Set *pids = NULL; |
663996b3 MS |
216 | |
217 | if (wait_for_exit) | |
5eef597e | 218 | pids = set_new(NULL); |
663996b3 MS |
219 | |
220 | assert_se(sigemptyset(&mask) == 0); | |
221 | assert_se(sigaddset(&mask, SIGCHLD) == 0); | |
222 | assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0); | |
223 | ||
224 | if (kill(-1, SIGSTOP) < 0 && errno != ESRCH) | |
f47781d8 | 225 | log_warning_errno(errno, "kill(-1, SIGSTOP) failed: %m"); |
663996b3 | 226 | |
60f067b4 | 227 | killall(sig, pids, send_sighup); |
663996b3 MS |
228 | |
229 | if (kill(-1, SIGCONT) < 0 && errno != ESRCH) | |
f47781d8 | 230 | log_warning_errno(errno, "kill(-1, SIGCONT) failed: %m"); |
663996b3 MS |
231 | |
232 | if (wait_for_exit) | |
233 | wait_for_children(pids, &mask); | |
234 | ||
235 | assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0); | |
663996b3 | 236 | } |