--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "build-path.h"
+#include "escape.h"
+#include "event-util.h"
+#include "exit-status.h"
+#include "fd-util.h"
+#include "fork-journal.h"
+#include "log.h"
+#include "notify-recv.h"
+#include "parse-util.h"
+#include "process-util.h"
+#include "signal-util.h"
+#include "socket-util.h"
+#include "strv.h"
+
+static int on_child_exit(sd_event_source *s, const siginfo_t *si, void *userdata) {
+ PidRef *child = ASSERT_PTR(userdata);
+
+ assert(si);
+ assert(si->si_pid == child->pid);
+
+ /* Let's first do some debug logging about the exit status of the child */
+
+ if (si->si_code == CLD_EXITED) {
+ if (si->si_status == EXIT_SUCCESS)
+ log_debug("journalctl " PID_FMT " exited successfully.", si->si_pid);
+ else
+ log_debug("journalctl " PID_FMT " died with a failure exit status %i, ignoring.", si->si_pid, si->si_status);
+ } else if (si->si_code == CLD_KILLED)
+ log_debug("journalctl " PID_FMT " was killed by signal %s, ignoring.", si->si_pid, signal_to_string(si->si_status));
+ else if (si->si_code == CLD_DUMPED)
+ log_debug("journalctl " PID_FMT " dumped core by signal %s, ignoring.", si->si_pid, signal_to_string(si->si_status));
+ else
+ log_debug("Got unexpected exit code %i via SIGCHLD, ignoring.", si->si_code);
+
+ /* And let's then fail the whole thing, because regardless what the exit status of the child is
+ * (i.e. even if successful), if it exits before sending READY=1 something is wrong. */
+
+ return log_debug_errno(SYNTHETIC_ERRNO(EPROTO), "Child " PID_FMT " died before sending notification message.", child->pid);
+}
+
+static int on_child_notify(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ PidRef *child = ASSERT_PTR(userdata);
+ int r;
+
+ assert(s);
+ assert(fd >= 0);
+
+ _cleanup_strv_free_ char **msg = NULL;
+ _cleanup_(pidref_done) PidRef sender = PIDREF_NULL;
+ r = notify_recv_strv(fd, &msg, /* ret_ucred= */ NULL, &sender);
+ if (r == -EAGAIN)
+ return 0;
+ if (r < 0)
+ return r;
+
+ if (!pidref_equal(child, &sender)) {
+ log_warning("Received notification message from unexpected process " PID_FMT " (expected " PID_FMT "), ignoring.",
+ sender.pid, child->pid);
+ return 0;
+ }
+
+ if (strv_contains(msg, "READY=1"))
+ return sd_event_exit(sd_event_source_get_event(s), EXIT_SUCCESS);
+
+ const char *e = strv_find_startswith(msg, "ERRNO=");
+ if (e) {
+ int error;
+
+ r = safe_atoi(e, &error);
+ if (r < 0) {
+ log_debug_errno(r, "Received invalid ERRNO= notification message, ignoring: %s", e);
+ return 0;
+ }
+ if (error <= 0) {
+ log_debug("Received non-positive ERRNO= notification message, ignoring: %m");
+ return 0;
+ }
+
+ return -error;
+ }
+
+ return 0;
+}
+
+int journal_fork(RuntimeScope scope, const char * const *units, PidRef *ret_pidref) {
+ int r;
+
+ assert(scope >= 0);
+ assert(scope < _RUNTIME_SCOPE_MAX);
+ assert(ret_pidref);
+
+ if (!is_main_thread())
+ return -EPERM;
+
+ if (strv_isempty((char**) units))
+ return 0;
+
+ _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+ r = sd_event_new(&event);
+ if (r < 0)
+ return r;
+
+ _cleanup_(sd_event_source_disable_unrefp) sd_event_source *notify_event_source = NULL;
+ _cleanup_(pidref_done_sigkill_wait) PidRef child = PIDREF_NULL;
+ _cleanup_free_ char *addr_string = NULL;
+ r = notify_socket_prepare(
+ event,
+ SD_EVENT_PRIORITY_NORMAL-10, /* We want the notification message from the child before the SIGCHLD */
+ on_child_notify,
+ &child,
+ &addr_string,
+ ¬ify_event_source);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_exit_on_failure(notify_event_source, true);
+ if (r < 0)
+ return r;
+
+ _cleanup_strv_free_ char **argv = strv_new(
+ "journalctl",
+ "-q",
+ "--follow",
+ "--no-pager",
+ "--lines=1");
+ if (!argv)
+ return log_oom_debug();
+
+ STRV_FOREACH(u, units)
+ if (strv_extendf(&argv,
+ scope == RUNTIME_SCOPE_SYSTEM ? "--unit=%s" : "--user-unit=%s",
+ *u) < 0)
+ return log_oom_debug();
+
+ if (DEBUG_LOGGING) {
+ _cleanup_free_ char *l = quote_command_line(argv, SHELL_ESCAPE_EMPTY);
+ log_debug("Invoking '%s' as child.", strnull(l));
+ }
+
+ BLOCK_SIGNALS(SIGCHLD);
+
+ r = pidref_safe_fork_full(
+ "(journalctl)",
+ (const int[3]) { -EBADF, STDOUT_FILENO, STDERR_FILENO },
+ /* except_fds= */ NULL,
+ /* n_except_fds= */ 0,
+ FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGTERM|FORK_CLOSE_ALL_FDS|FORK_REARRANGE_STDIO,
+ &child);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ /* In the child: */
+
+ if (setenv("NOTIFY_SOCKET", addr_string, /* overwrite= */ true) < 0) {
+ log_debug_errno(errno, "Failed to set $NOTIFY_SOCKET: %m");
+ _exit(EXIT_MEMORY);
+ }
+
+ r = invoke_callout_binary(argv[0], (char**) argv);
+ log_debug_errno(r, "Failed to invoke journalctl: %m");
+ _exit(EXIT_EXEC);
+ }
+
+ _cleanup_(sd_event_source_disable_unrefp) sd_event_source *child_event_source = NULL;
+ r = event_add_child_pidref(event, &child_event_source, &child, WEXITED, on_child_exit, &child);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_exit_on_failure(child_event_source, true);
+ if (r < 0)
+ return r;
+
+ (void) sd_event_source_set_description(child_event_source, "fork-journal-child");
+
+ r = sd_event_loop(event);
+ if (r < 0)
+ return r;
+ assert(r == 0);
+
+ *ret_pidref = TAKE_PIDREF(child);
+
+ return 0;
+}
+
+void journal_terminate(PidRef *pidref) {
+ int r;
+
+ if (!pidref_is_set(pidref))
+ return;
+
+ r = pidref_kill(pidref, SIGTERM);
+ if (r < 0)
+ log_debug_errno(r, "Failed to send SIGTERM to journalctl child " PID_FMT ", ignoring: %m", pidref->pid);
+
+ (void) pidref_wait_for_terminate_and_check("journalctl", pidref, /* flags= */ 0);
+ pidref_done(pidref);
+}
projects / thirdparty / systemd.git / commitdiff
