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-rw-r--r--src/userdb/userdbd-manager.c301
1 files changed, 301 insertions, 0 deletions
diff --git a/src/userdb/userdbd-manager.c b/src/userdb/userdbd-manager.c
new file mode 100644
index 0000000..f8d315c
--- /dev/null
+++ b/src/userdb/userdbd-manager.c
@@ -0,0 +1,301 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/wait.h>
+
+#include "sd-daemon.h"
+
+#include "fd-util.h"
+#include "fs-util.h"
+#include "mkdir.h"
+#include "process-util.h"
+#include "set.h"
+#include "signal-util.h"
+#include "socket-util.h"
+#include "stdio-util.h"
+#include "umask-util.h"
+#include "userdbd-manager.h"
+
+#define LISTEN_TIMEOUT_USEC (25 * USEC_PER_SEC)
+
+static int start_workers(Manager *m, bool explicit_request);
+
+static int on_sigchld(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+ Manager *m = userdata;
+
+ assert(s);
+ assert(m);
+
+ for (;;) {
+ siginfo_t siginfo = {};
+ bool removed = false;
+
+ if (waitid(P_ALL, 0, &siginfo, WNOHANG|WEXITED) < 0) {
+ if (errno == ECHILD)
+ break;
+
+ log_warning_errno(errno, "Failed to invoke waitid(): %m");
+ break;
+ }
+ if (siginfo.si_pid == 0)
+ break;
+
+ if (set_remove(m->workers_dynamic, PID_TO_PTR(siginfo.si_pid)))
+ removed = true;
+ if (set_remove(m->workers_fixed, PID_TO_PTR(siginfo.si_pid)))
+ removed = true;
+
+ if (!removed) {
+ log_warning("Weird, got SIGCHLD for unknown child " PID_FMT ", ignoring.", siginfo.si_pid);
+ continue;
+ }
+
+ if (siginfo.si_code == CLD_EXITED) {
+ if (siginfo.si_status == EXIT_SUCCESS)
+ log_debug("Worker " PID_FMT " exited successfully.", siginfo.si_pid);
+ else
+ log_warning("Worker " PID_FMT " died with a failure exit status %i, ignoring.", siginfo.si_pid, siginfo.si_status);
+ } else if (siginfo.si_code == CLD_KILLED)
+ log_warning("Worker " PID_FMT " was killed by signal %s, ignoring.", siginfo.si_pid, signal_to_string(siginfo.si_status));
+ else if (siginfo.si_code == CLD_DUMPED)
+ log_warning("Worker " PID_FMT " dumped core by signal %s, ignoring.", siginfo.si_pid, signal_to_string(siginfo.si_status));
+ else
+ log_warning("Can't handle SIGCHLD of this type");
+ }
+
+ (void) start_workers(m, false); /* Fill up workers again if we fell below the low watermark */
+ return 0;
+}
+
+static int on_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+ Manager *m = userdata;
+
+ assert(s);
+ assert(m);
+
+ (void) start_workers(m, true); /* Workers told us there's more work, let's add one more worker as long as we are below the high watermark */
+ return 0;
+}
+
+int manager_new(Manager **ret) {
+ _cleanup_(manager_freep) Manager *m = NULL;
+ int r;
+
+ m = new(Manager, 1);
+ if (!m)
+ return -ENOMEM;
+
+ *m = (Manager) {
+ .listen_fd = -1,
+ .worker_ratelimit = {
+ .interval = 5 * USEC_PER_SEC,
+ .burst = 50,
+ },
+ };
+
+ r = sd_event_new(&m->event);
+ if (r < 0)
+ return r;
+
+ r = sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
+ if (r < 0)
+ return r;
+
+ r = sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
+ if (r < 0)
+ return r;
+
+ (void) sd_event_set_watchdog(m->event, true);
+
+ m->workers_fixed = set_new(NULL);
+ m->workers_dynamic = set_new(NULL);
+
+ if (!m->workers_fixed || !m->workers_dynamic)
+ return -ENOMEM;
+
+ r = sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, on_sigusr2, m);
+ if (r < 0)
+ return r;
+
+ r = sd_event_add_signal(m->event, &m->sigchld_event_source, SIGCHLD, on_sigchld, m);
+ if (r < 0)
+ return r;
+
+ *ret = TAKE_PTR(m);
+ return 0;
+}
+
+Manager* manager_free(Manager *m) {
+ if (!m)
+ return NULL;
+
+ set_free(m->workers_fixed);
+ set_free(m->workers_dynamic);
+
+ sd_event_source_disable_unref(m->sigusr2_event_source);
+ sd_event_source_disable_unref(m->sigchld_event_source);
+
+ sd_event_unref(m->event);
+
+ return mfree(m);
+}
+
+static size_t manager_current_workers(Manager *m) {
+ assert(m);
+
+ return set_size(m->workers_fixed) + set_size(m->workers_dynamic);
+}
+
+static int start_one_worker(Manager *m) {
+ bool fixed;
+ pid_t pid;
+ int r;
+
+ assert(m);
+
+ fixed = set_size(m->workers_fixed) < USERDB_WORKERS_MIN;
+
+ r = safe_fork("(sd-worker)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
+ if (r < 0)
+ return log_error_errno(r, "Failed to fork new worker child: %m");
+ if (r == 0) {
+ char pids[DECIMAL_STR_MAX(pid_t)];
+ /* Child */
+
+ log_close();
+
+ r = close_all_fds(&m->listen_fd, 1);
+ if (r < 0) {
+ log_error_errno(r, "Failed to close fds in child: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ log_open();
+
+ if (m->listen_fd == 3) {
+ r = fd_cloexec(3, false);
+ if (r < 0) {
+ log_error_errno(r, "Failed to turn off O_CLOEXEC for fd 3: %m");
+ _exit(EXIT_FAILURE);
+ }
+ } else {
+ if (dup2(m->listen_fd, 3) < 0) { /* dup2() creates with O_CLOEXEC off */
+ log_error_errno(errno, "Failed to move listen fd to 3: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ safe_close(m->listen_fd);
+ }
+
+ xsprintf(pids, PID_FMT, pid);
+ if (setenv("LISTEN_PID", pids, 1) < 0) {
+ log_error_errno(errno, "Failed to set $LISTEN_PID: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (setenv("LISTEN_FDS", "1", 1) < 0) {
+ log_error_errno(errno, "Failed to set $LISTEN_FDS: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+
+ if (setenv("USERDB_FIXED_WORKER", one_zero(fixed), 1) < 0) {
+ log_error_errno(errno, "Failed to set $USERDB_FIXED_WORKER: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ /* execl("/home/lennart/projects/systemd/build/systemd-userwork", "systemd-userwork", "xxxxxxxxxxxxxxxx", NULL); /\* With some extra space rename_process() can make use of *\/ */
+ /* execl("/usr/bin/valgrind", "valgrind", "/home/lennart/projects/systemd/build/systemd-userwork", "systemd-userwork", "xxxxxxxxxxxxxxxx", NULL); /\* With some extra space rename_process() can make use of *\/ */
+
+ execl(SYSTEMD_USERWORK_PATH, "systemd-userwork", "xxxxxxxxxxxxxxxx", NULL); /* With some extra space rename_process() can make use of */
+ log_error_errno(errno, "Failed start worker process: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (fixed)
+ r = set_put(m->workers_fixed, PID_TO_PTR(pid));
+ else
+ r = set_put(m->workers_dynamic, PID_TO_PTR(pid));
+ if (r < 0)
+ return log_error_errno(r, "Failed to add child process to set: %m");
+
+ return 0;
+}
+
+static int start_workers(Manager *m, bool explicit_request) {
+ int r;
+
+ assert(m);
+
+ for (;;) {
+ size_t n;
+
+ n = manager_current_workers(m);
+ if (n >= USERDB_WORKERS_MIN && (!explicit_request || n >= USERDB_WORKERS_MAX))
+ break;
+
+ if (!ratelimit_below(&m->worker_ratelimit)) {
+ /* If we keep starting workers too often, let's fail the whole daemon, something is wrong */
+ sd_event_exit(m->event, EXIT_FAILURE);
+
+ return log_error_errno(SYNTHETIC_ERRNO(EUCLEAN), "Worker threads requested too frequently, something is wrong.");
+ }
+
+ r = start_one_worker(m);
+ if (r < 0)
+ return r;
+
+ explicit_request = false;
+ }
+
+ return 0;
+}
+
+int manager_startup(Manager *m) {
+ struct timeval ts;
+ int n, r;
+
+ assert(m);
+ assert(m->listen_fd < 0);
+
+ n = sd_listen_fds(false);
+ if (n < 0)
+ return log_error_errno(n, "Failed to determine number of passed file descriptors: %m");
+ if (n > 1)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected one listening fd, got %i.", n);
+ if (n == 1)
+ m->listen_fd = SD_LISTEN_FDS_START;
+ else {
+ union sockaddr_union sockaddr = {
+ .un.sun_family = AF_UNIX,
+ .un.sun_path = "/run/systemd/userdb/io.systemd.NameServiceSwitch",
+ };
+
+ r = mkdir_p("/run/systemd/userdb", 0755);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create /run/systemd/userdb: %m");
+
+ m->listen_fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+ if (m->listen_fd < 0)
+ return log_error_errno(errno, "Failed to bind on socket: %m");
+
+ (void) sockaddr_un_unlink(&sockaddr.un);
+
+ RUN_WITH_UMASK(0000)
+ if (bind(m->listen_fd, &sockaddr.sa, SOCKADDR_UN_LEN(sockaddr.un)) < 0)
+ return log_error_errno(errno, "Failed to bind socket: %m");
+
+ r = symlink_idempotent("io.systemd.NameServiceSwitch", "/run/systemd/userdb/io.systemd.Multiplexer", false);
+ if (r < 0)
+ return log_error_errno(r, "Failed to bind io.systemd.Multiplexer: %m");
+
+ if (listen(m->listen_fd, SOMAXCONN) < 0)
+ return log_error_errno(errno, "Failed to listen on socket: %m");
+ }
+
+ /* Let's make sure every accept() call on this socket times out after 25s. This allows workers to be
+ * GC'ed on idle */
+ if (setsockopt(m->listen_fd, SOL_SOCKET, SO_RCVTIMEO, timeval_store(&ts, LISTEN_TIMEOUT_USEC), sizeof(ts)) < 0)
+ return log_error_errno(errno, "Failed to se SO_RCVTIMEO: %m");
+
+ return start_workers(m, false);
+}