/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 ProFUSION embedded systems
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include "util.h"
#include "def.h"
#include "killall.h"
#include "set.h"
#define TIMEOUT_USEC (10 * USEC_PER_SEC)
static bool ignore_proc(pid_t pid) {
_cleanup_fclose_ FILE *f = NULL;
char c;
const char *p;
size_t count;
uid_t uid;
int r;
/* We are PID 1, let's not commit suicide */
if (pid == 1)
return true;
r = get_process_uid(pid, &uid);
if (r < 0)
return true; /* not really, but better safe than sorry */
/* Non-root processes otherwise are always subject to be killed */
if (uid != 0)
return false;
p = procfs_file_alloca(pid, "cmdline");
f = fopen(p, "re");
if (!f)
return true; /* not really, but has the desired effect */
count = fread(&c, 1, 1, f);
/* Kernel threads have an empty cmdline */
if (count <= 0)
return true;
/* Processes with argv[0][0] = '@' we ignore from the killing
* spree.
*
* http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */
if (count == 1 && c == '@')
return true;
return false;
}
static void wait_for_children(Set *pids, sigset_t *mask) {
usec_t until;
assert(mask);
if (set_isempty(pids))
return;
until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
for (;;) {
struct timespec ts;
int k;
usec_t n;
void *p;
Iterator i;
/* First, let the kernel inform us about killed
* children. Most processes will probably be our
* children, but some are not (might be our
* grandchildren instead...). */
for (;;) {
pid_t pid;
pid = waitpid(-1, NULL, WNOHANG);
if (pid == 0)
break;
if (pid < 0) {
if (errno == ECHILD)
break;
log_error("waitpid() failed: %m");
return;
}
set_remove(pids, ULONG_TO_PTR(pid));
}
/* Now explicitly check who might be remaining, who
* might not be our child. */
SET_FOREACH(p, pids, i) {
/* We misuse getpgid as a check whether a
* process still exists. */
if (getpgid((pid_t) PTR_TO_ULONG(p)) >= 0)
continue;
if (errno != ESRCH)
continue;
set_remove(pids, p);
}
if (set_isempty(pids))
return;
n = now(CLOCK_MONOTONIC);
if (n >= until)
return;
timespec_store(&ts, until - n);
k = sigtimedwait(mask, NULL, &ts);
if (k != SIGCHLD) {
if (k < 0 && errno != EAGAIN) {
log_error("sigtimedwait() failed: %m");
return;
}
if (k >= 0)
log_warning("sigtimedwait() returned unexpected signal.");
}
}
}
static int killall(int sig, Set *pids, bool send_sighup) {
_cleanup_closedir_ DIR *dir = NULL;
struct dirent *d;
dir = opendir("/proc");
if (!dir)
return -errno;
while ((d = readdir(dir))) {
pid_t pid;
if (d->d_type != DT_DIR &&
d->d_type != DT_UNKNOWN)
continue;
if (parse_pid(d->d_name, &pid) < 0)
continue;
if (ignore_proc(pid))
continue;
if (sig == SIGKILL) {
_cleanup_free_ char *s = NULL;
get_process_comm(pid, &s);
log_notice("Sending SIGKILL to PID "PID_FMT" (%s).", pid, strna(s));
}
if (kill(pid, sig) >= 0) {
if (pids)
set_put(pids, ULONG_TO_PTR(pid));
} else if (errno != ENOENT)
log_warning("Could not kill %d: %m", pid);
if (send_sighup) {
/* Optionally, also send a SIGHUP signal, but
only if the process has a controlling
tty. This is useful to allow handling of
shells which ignore SIGTERM but react to
SIGHUP. We do not send this to processes that
have no controlling TTY since we don't want to
trigger reloads of daemon processes. Also we
make sure to only send this after SIGTERM so
that SIGTERM is always first in the queue. */
if (get_ctty_devnr(pid, NULL) >= 0)
kill(pid, SIGHUP);
}
}
return set_size(pids);
}
void broadcast_signal(int sig, bool wait_for_exit, bool send_sighup) {
sigset_t mask, oldmask;
_cleanup_set_free_ Set *pids = NULL;
if (wait_for_exit)
pids = set_new(NULL);
assert_se(sigemptyset(&mask) == 0);
assert_se(sigaddset(&mask, SIGCHLD) == 0);
assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
log_warning("kill(-1, SIGSTOP) failed: %m");
killall(sig, pids, send_sighup);
if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
log_warning("kill(-1, SIGCONT) failed: %m");
if (wait_for_exit)
wait_for_children(pids, &mask);
assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
}