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Diffstat (limited to 'src/libcore/killall.c')
| -rw-r--r-- | src/libcore/killall.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/src/libcore/killall.c b/src/libcore/killall.c new file mode 100644 index 0000000000..09378f7085 --- /dev/null +++ b/src/libcore/killall.c @@ -0,0 +1,249 @@ +/*** + 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 <errno.h> +#include <signal.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "formats-util.h" +#include "killall.h" +#include "parse-util.h" +#include "process-util.h" +#include "set.h" +#include "string-util.h" +#include "terminal-util.h" +#include "util.h" + +#define TIMEOUT_USEC (10 * USEC_PER_SEC) + +static bool ignore_proc(pid_t pid, bool warn_rootfs) { + _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 (c == '@' && warn_rootfs) { + _cleanup_free_ char *comm = NULL; + + r = pid_from_same_root_fs(pid); + if (r < 0) + return true; + + get_process_comm(pid, &comm); + + if (r) + log_notice("Process " PID_FMT " (%s) has been been marked to be excluded from killing. It is " + "running from the root file system, and thus likely to block re-mounting of the " + "root file system to read-only. Please consider moving it into an initrd file " + "system instead.", pid, strna(comm)); + return true; + } else if (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_errno(errno, "waitpid() failed: %m"); + return; + } + + (void) set_remove(pids, PID_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(PTR_TO_PID(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_errno(errno, "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; + int r; + + 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, sig == SIGKILL && !in_initrd())) + 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) { + r = set_put(pids, PID_TO_PTR(pid)); + if (r < 0) + log_oom(); + } + } else if (errno != ENOENT) + log_warning_errno(errno, "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_errno(errno, "kill(-1, SIGSTOP) failed: %m"); + + killall(sig, pids, send_sighup); + + if (kill(-1, SIGCONT) < 0 && errno != ESRCH) + log_warning_errno(errno, "kill(-1, SIGCONT) failed: %m"); + + if (wait_for_exit) + wait_for_children(pids, &mask); + + assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0); +} |