Adding upstream version 252.22.upstream/252.22

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 283 insertions, 0 deletions

diff --git a/src/shared/killall.c b/src/shared/killall.c
new file mode 100644
index 0000000..1c98972
--- /dev/null
+++ b/src/shared/killall.c
@@ -0,0 +1,283 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2010 ProFUSION embedded systems
+***/
+
+#include <errno.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "def.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "killall.h"
+#include "parse-util.h"
+#include "process-util.h"
+#include "set.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "terminal-util.h"
+#include "util.h"
+
+static bool ignore_proc(pid_t pid, bool warn_rootfs) {
+        _cleanup_fclose_ FILE *f = NULL;
+        const char *p;
+        char c = 0;
+        uid_t uid;
+        int r;
+
+        /* We are PID 1, let's not commit suicide */
+        if (pid <= 1)
+                return true;
+
+        /* Ignore kernel threads */
+        r = is_kernel_thread(pid);
+        if (r != 0)
+                return true; /* also ignore processes where we can't determine this */
+
+        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 */
+
+        /* Try to read the first character of the command line. If the cmdline is empty (which might be the case for
+         * kernel threads but potentially also other stuff), this line won't do anything, but we don't care much, as
+         * actual kernel threads are already filtered out above. */
+        (void) fread(&c, 1, 1, f);
+
+        /* Processes with argv[0][0] = '@' we ignore from the killing spree.
+         *
+         * https://systemd.io/ROOT_STORAGE_DAEMONS */
+        if (c != '@')
+                return false;
+
+        if (warn_rootfs &&
+            pid_from_same_root_fs(pid) > 0) {
+
+                _cleanup_free_ char *comm = NULL;
+
+                (void) get_process_comm(pid, &comm);
+
+                log_notice("Process " PID_FMT " (%s) has 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;
+}
+
+static void log_children_no_yet_killed(Set *pids) {
+        _cleanup_free_ char *lst_child = NULL;
+        void *p;
+        int r;
+
+        SET_FOREACH(p, pids) {
+                _cleanup_free_ char *s = NULL;
+
+                if (get_process_comm(PTR_TO_PID(p), &s) >= 0)
+                        r = strextendf(&lst_child, ", " PID_FMT " (%s)", PTR_TO_PID(p), s);
+                else
+                        r = strextendf(&lst_child, ", " PID_FMT, PTR_TO_PID(p));
+                if (r < 0)
+                        return (void) log_oom();
+        }
+
+        if (isempty(lst_child))
+                return;
+
+        log_warning("Waiting for process: %s", lst_child + 2);
+}
+
+static int wait_for_children(Set *pids, sigset_t *mask, usec_t timeout) {
+        usec_t until, date_log_child, n;
+
+        assert(mask);
+
+        /* Return the number of children remaining in the pids set: That correspond to the number
+         * of processes still "alive" after the timeout */
+
+        if (set_isempty(pids))
+                return 0;
+
+        n = now(CLOCK_MONOTONIC);
+        until = usec_add(n, timeout);
+        date_log_child = usec_add(n, 10u * USEC_PER_SEC);
+        if (date_log_child > until)
+                date_log_child = usec_add(n, timeout / 2u);
+
+        for (;;) {
+                struct timespec ts;
+                int k;
+                void *p;
+
+                /* 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;
+
+                                return log_error_errno(errno, "waitpid() failed: %m");
+                        }
+
+                        (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) {
+
+                        /* kill(pid, 0) sends no signal, but it tells
+                         * us whether the process still exists. */
+                        if (kill(PTR_TO_PID(p), 0) == 0)
+                                continue;
+
+                        if (errno != ESRCH)
+                                continue;
+
+                        set_remove(pids, p);
+                }
+
+                if (set_isempty(pids))
+                        return 0;
+
+                n = now(CLOCK_MONOTONIC);
+                if (date_log_child > 0 && n >= date_log_child) {
+                        log_children_no_yet_killed(pids);
+                        /* Log the children not yet killed only once */
+                        date_log_child = 0;
+                }
+
+                if (n >= until)
+                        return set_size(pids);
+
+                if (date_log_child > 0)
+                        timespec_store(&ts, MIN(until - n, date_log_child - n));
+                else
+                        timespec_store(&ts, until - n);
+
+                k = sigtimedwait(mask, NULL, &ts);
+                if (k != SIGCHLD) {
+
+                        if (k < 0 && errno != EAGAIN)
+                                return log_error_errno(errno, "sigtimedwait() failed: %m");
+
+                        if (k >= 0)
+                                log_warning("sigtimedwait() returned unexpected signal.");
+                }
+        }
+}
+
+static int killall(int sig, Set *pids, bool send_sighup) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        int n_killed = 0;
+
+        /* Send the specified signal to all remaining processes, if not excluded by ignore_proc().
+         * Returns the number of processes to which the specified signal was sent */
+
+        dir = opendir("/proc");
+        if (!dir)
+                return log_warning_errno(errno, "opendir(/proc) failed: %m");
+
+        FOREACH_DIRENT_ALL(de, dir, break) {
+                pid_t pid;
+                int r;
+
+                if (!IN_SET(de->d_type, DT_DIR, DT_UNKNOWN))
+                        continue;
+
+                if (parse_pid(de->d_name, &pid) < 0)
+                        continue;
+
+                if (ignore_proc(pid, sig == SIGKILL && !in_initrd()))
+                        continue;
+
+                if (sig == SIGKILL) {
+                        _cleanup_free_ char *s = NULL;
+
+                        (void) get_process_comm(pid, &s);
+                        log_notice("Sending SIGKILL to PID "PID_FMT" (%s).", pid, strna(s));
+                }
+
+                if (kill(pid, sig) >= 0) {
+                        n_killed++;
+                        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)
+                                /* it's OK if the process is gone, just ignore the result */
+                                (void) kill(pid, SIGHUP);
+                }
+        }
+
+        return n_killed;
+}
+
+int broadcast_signal(int sig, bool wait_for_exit, bool send_sighup, usec_t timeout) {
+        int n_children_left;
+        sigset_t mask, oldmask;
+        _cleanup_set_free_ Set *pids = NULL;
+
+        /* Send the specified signal to all remaining processes, if not excluded by ignore_proc().
+         * Return:
+         *  - The number of processes still "alive" after the timeout (that should have been killed)
+         *    if the function needs to wait for the end of the processes (wait_for_exit).
+         *  - Otherwise, the number of processes to which the specified signal was sent */
+
+        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");
+
+        n_children_left = 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 && n_children_left > 0)
+                n_children_left = wait_for_children(pids, &mask, timeout);
+
+        assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
+
+        return n_children_left;
+}