diff options
Diffstat (limited to 'src/core/killall.c')
| -rw-r--r-- | src/core/killall.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/src/core/killall.c b/src/core/killall.c new file mode 100644 index 0000000000..5f589eaf47 --- /dev/null +++ b/src/core/killall.c @@ -0,0 +1,176 @@ +/*-*- 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 "util.h" +#include "def.h" +#include "killall.h" + +#define TIMEOUT_USEC (5 * USEC_PER_SEC) + +static bool ignore_proc(pid_t pid) { + char buf[PATH_MAX]; + FILE *f; + char c; + 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; + + snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long) pid); + char_array_0(buf); + + f = fopen(buf, "re"); + if (!f) + return true; /* not really, but has the desired effect */ + + count = fread(&c, 1, 1, f); + fclose(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(int n_processes, sigset_t *mask) { + usec_t until; + + assert(mask); + + until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC; + for (;;) { + struct timespec ts; + int k; + usec_t n; + + for (;;) { + pid_t pid = waitpid(-1, NULL, WNOHANG); + + if (pid == 0) + break; + + if (pid < 0 && errno == ECHILD) + return; + + if (n_processes > 0) + if (--n_processes == 0) + return; + } + + n = now(CLOCK_MONOTONIC); + if (n >= until) + return; + + timespec_store(&ts, until - n); + + if ((k = sigtimedwait(mask, NULL, &ts)) != 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) { + DIR *dir; + struct dirent *d; + unsigned int n_processes = 0; + + 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 (kill(pid, sig) >= 0) + n_processes++; + else if (errno != ENOENT) + log_warning("Could not kill %d: %m", pid); + } + + closedir(dir); + + return n_processes; +} + +void broadcast_signal(int sig) { + sigset_t mask, oldmask; + int n_processes; + + 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"); + + n_processes = killall(sig); + + if (kill(-1, SIGCONT) < 0 && errno != ESRCH) + log_warning("kill(-1, SIGCONT) failed: %m"); + + if (n_processes <= 0) + goto finish; + + wait_for_children(n_processes, &mask); + +finish: + sigprocmask(SIG_SETMASK, &oldmask, NULL); +} |