core: go on a killing spree when transitioning from initrd to main system
This commit is contained in:
Lennart Poettering
parent
32c4bef882
commit
bd3fa1d243
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@ -877,7 +877,9 @@ libsystemd_core_la_SOURCES = \
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src/core/build.h \
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src/core/sysfs-show.h \
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src/core/switch-root.h \
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src/core/switch-root.c
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src/core/switch-root.c \
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src/core/killall.h \
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src/core/killall.c
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nodist_libsystemd_core_la_SOURCES = \
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src/core/load-fragment-gperf.c \
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@ -1134,7 +1136,9 @@ systemd_shutdown_SOURCES = \
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src/core/umount.h \
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src/core/shutdown.c \
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src/core/mount-setup.c \
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src/core/mount-setup.h
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src/core/mount-setup.h \
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src/core/killall.h \
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src/core/killall.c
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systemd_shutdown_LDADD = \
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libsystemd-label.la \
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176
src/core/killall.c
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176
src/core/killall.c
Normal file
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@ -0,0 +1,176 @@
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 ProFUSION embedded systems
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/wait.h>
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#include <signal.h>
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#include <errno.h>
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#include "util.h"
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#include "def.h"
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#include "killall.h"
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#define TIMEOUT_USEC (5 * USEC_PER_SEC)
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static bool ignore_proc(pid_t pid) {
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char buf[PATH_MAX];
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FILE *f;
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char c;
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size_t count;
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uid_t uid;
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int r;
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/* We are PID 1, let's not commit suicide */
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if (pid == 1)
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return true;
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r = get_process_uid(pid, &uid);
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if (r < 0)
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return true; /* not really, but better safe than sorry */
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/* Non-root processes otherwise are always subject to be killed */
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if (uid != 0)
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return false;
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snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long) pid);
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char_array_0(buf);
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f = fopen(buf, "re");
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if (!f)
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return true; /* not really, but has the desired effect */
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count = fread(&c, 1, 1, f);
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fclose(f);
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/* Kernel threads have an empty cmdline */
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if (count <= 0)
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return true;
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/* Processes with argv[0][0] = '@' we ignore from the killing
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* spree.
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*
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* http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */
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if (count == 1 && c == '@')
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return true;
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return false;
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}
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static void wait_for_children(int n_processes, sigset_t *mask) {
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usec_t until;
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assert(mask);
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until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
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for (;;) {
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struct timespec ts;
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int k;
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usec_t n;
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for (;;) {
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pid_t pid = waitpid(-1, NULL, WNOHANG);
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if (pid == 0)
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break;
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if (pid < 0 && errno == ECHILD)
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return;
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if (n_processes > 0)
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if (--n_processes == 0)
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return;
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}
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n = now(CLOCK_MONOTONIC);
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if (n >= until)
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return;
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timespec_store(&ts, until - n);
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if ((k = sigtimedwait(mask, NULL, &ts)) != SIGCHLD) {
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if (k < 0 && errno != EAGAIN) {
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log_error("sigtimedwait() failed: %m");
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return;
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}
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if (k >= 0)
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log_warning("sigtimedwait() returned unexpected signal.");
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}
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}
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}
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static int killall(int sig) {
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DIR *dir;
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struct dirent *d;
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unsigned int n_processes = 0;
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dir = opendir("/proc");
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if (!dir)
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return -errno;
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while ((d = readdir(dir))) {
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pid_t pid;
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if (d->d_type != DT_DIR &&
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d->d_type != DT_UNKNOWN)
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continue;
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if (parse_pid(d->d_name, &pid) < 0)
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continue;
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if (ignore_proc(pid))
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continue;
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if (kill(pid, sig) >= 0)
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n_processes++;
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else if (errno != ENOENT)
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log_warning("Could not kill %d: %m", pid);
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}
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closedir(dir);
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return n_processes;
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}
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void broadcast_signal(int sig) {
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sigset_t mask, oldmask;
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int n_processes;
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assert_se(sigemptyset(&mask) == 0);
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assert_se(sigaddset(&mask, SIGCHLD) == 0);
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assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
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if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGSTOP) failed: %m");
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n_processes = killall(sig);
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if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGCONT) failed: %m");
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if (n_processes <= 0)
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goto finish;
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wait_for_children(n_processes, &mask);
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finish:
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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}
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27
src/core/killall.h
Normal file
27
src/core/killall.h
Normal file
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@ -0,0 +1,27 @@
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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#ifndef fookillallhfoo
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#define fookillallhfoo
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/***
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This file is part of systemd.
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Copyright 2012 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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void broadcast_signal(int sig);
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#endif
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@ -51,6 +51,7 @@
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#include "path-util.h"
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#include "switch-root.h"
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#include "capability.h"
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#include "killall.h"
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#include "mount-setup.h"
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#include "loopback-setup.h"
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@ -1676,6 +1677,11 @@ finish:
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make_console_stdio();
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if (switch_root_dir) {
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/* Kill all remaining processes from the initrd */
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broadcast_signal(SIGTERM);
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broadcast_signal(SIGKILL);
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/* And switch root */
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r = switch_root(switch_root_dir);
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if (r < 0)
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log_error("Failed to switch root, ignoring: %s", strerror(-r));
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@ -45,178 +45,8 @@
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#include "virt.h"
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#include "watchdog.h"
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#define TIMEOUT_USEC (5 * USEC_PER_SEC)
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#define FINALIZE_ATTEMPTS 50
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static bool ignore_proc(pid_t pid) {
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char buf[PATH_MAX];
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FILE *f;
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char c;
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size_t count;
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uid_t uid;
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int r;
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/* We are PID 1, let's not commit suicide */
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if (pid == 1)
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return true;
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r = get_process_uid(pid, &uid);
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if (r < 0)
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return true; /* not really, but better safe than sorry */
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/* Non-root processes otherwise are always subject to be killed */
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if (uid != 0)
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return false;
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snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long) pid);
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char_array_0(buf);
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f = fopen(buf, "re");
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if (!f)
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return true; /* not really, but has the desired effect */
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count = fread(&c, 1, 1, f);
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fclose(f);
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/* Kernel threads have an empty cmdline */
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if (count <= 0)
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return true;
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/* Processes with argv[0][0] = '@' we ignore from the killing
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* spree.
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*
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* http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */
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if (count == 1 && c == '@')
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return true;
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return false;
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}
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static int killall(int sign) {
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DIR *dir;
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struct dirent *d;
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unsigned int n_processes = 0;
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dir = opendir("/proc");
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if (!dir)
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return -errno;
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while ((d = readdir(dir))) {
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pid_t pid;
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if (parse_pid(d->d_name, &pid) < 0)
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continue;
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if (ignore_proc(pid))
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continue;
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if (kill(pid, sign) == 0)
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n_processes++;
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else
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log_warning("Could not kill %d: %m", pid);
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}
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closedir(dir);
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return n_processes;
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}
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static void wait_for_children(int n_processes, sigset_t *mask) {
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usec_t until;
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assert(mask);
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until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
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for (;;) {
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struct timespec ts;
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int k;
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usec_t n;
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for (;;) {
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pid_t pid = waitpid(-1, NULL, WNOHANG);
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if (pid == 0)
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break;
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if (pid < 0 && errno == ECHILD)
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return;
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if (n_processes > 0)
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if (--n_processes == 0)
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return;
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}
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n = now(CLOCK_MONOTONIC);
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if (n >= until)
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return;
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timespec_store(&ts, until - n);
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if ((k = sigtimedwait(mask, NULL, &ts)) != SIGCHLD) {
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if (k < 0 && errno != EAGAIN) {
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log_error("sigtimedwait() failed: %m");
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return;
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}
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if (k >= 0)
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log_warning("sigtimedwait() returned unexpected signal.");
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}
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}
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}
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static void send_signal(int sign) {
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sigset_t mask, oldmask;
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int n_processes;
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assert_se(sigemptyset(&mask) == 0);
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assert_se(sigaddset(&mask, SIGCHLD) == 0);
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assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
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if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGSTOP) failed: %m");
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n_processes = killall(sign);
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if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGCONT) failed: %m");
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if (n_processes <= 0)
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goto finish;
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wait_for_children(n_processes, &mask);
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finish:
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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}
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static void ultimate_send_signal(int sign) {
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sigset_t mask, oldmask;
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int r;
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assert_se(sigemptyset(&mask) == 0);
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assert_se(sigaddset(&mask, SIGCHLD) == 0);
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assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
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if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGSTOP) failed: %m");
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r = kill(-1, sign);
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if (r < 0 && errno != ESRCH)
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log_warning("kill(-1, %s) failed: %m", signal_to_string(sign));
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if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGCONT) failed: %m");
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if (r < 0)
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goto finish;
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wait_for_children(0, &mask);
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finish:
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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}
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static int prepare_new_root(void) {
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static const char dirs[] =
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"/run/initramfs/oldroot\0"
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@ -267,6 +97,7 @@ static int prepare_new_root(void) {
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}
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static int pivot_to_new_root(void) {
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if (chdir("/run/initramfs") < 0) {
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log_error("Failed to change directory to /run/initramfs: %m");
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return -errno;
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@ -302,7 +133,7 @@ int main(int argc, char *argv[]) {
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int cmd, r;
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unsigned retries;
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bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
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bool killed_everbody = false, in_container, use_watchdog = false;
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bool in_container, use_watchdog = false;
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char *arguments[3];
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log_parse_environment();
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@ -345,10 +176,10 @@ int main(int argc, char *argv[]) {
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mlockall(MCL_CURRENT|MCL_FUTURE);
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log_info("Sending SIGTERM to remaining processes...");
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send_signal(SIGTERM);
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broadcast_signal(SIGTERM);
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log_info("Sending SIGKILL to remaining processes...");
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send_signal(SIGKILL);
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broadcast_signal(SIGKILL);
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if (in_container) {
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need_swapoff = false;
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@ -414,21 +245,10 @@ int main(int argc, char *argv[]) {
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}
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/* If in this iteration we didn't manage to
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* unmount/deactivate anything, we either kill more
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* processes, or simply give up */
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* unmount/deactivate anything, we simply give up */
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if (!changed) {
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if (killed_everbody) {
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/* Hmm, we already killed everybody,
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* let's just give up */
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log_error("Cannot finalize remaining file systems and devices, giving up.");
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break;
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}
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log_warning("Cannot finalize remaining file systems and devices, trying to kill remaining processes.");
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ultimate_send_signal(SIGTERM);
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ultimate_send_signal(SIGKILL);
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killed_everbody = true;
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log_error("Cannot finalize remaining file systems and devices, giving up.");
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break;
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}
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log_debug("Couldn't finalize remaining file systems and devices after %u retries, trying again.", retries+1);
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