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authorLennart Poettering <lennart@poettering.net>2012-07-13 14:41:57 +0200
committerLennart Poettering <lennart@poettering.net>2012-07-13 14:41:57 +0200
commitbd3fa1d2434aa28564251ac4da34d01537de8c4b (patch)
treecf92230cd221fc4cfb5df8a1d04c0ec8cd092e10 /src/core/killall.c
parent32c4bef8826f1231984d735944cb02a01d21177a (diff)
core: go on a killing spree when transitioning from initrd to main system
Diffstat (limited to 'src/core/killall.c')
-rw-r--r--src/core/killall.c176
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);
+}