Adding upstream version 256.upstream/256

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

1 files changed, 277 insertions, 0 deletions

diff --git a/src/mountfsd/mountfsd-manager.c b/src/mountfsd/mountfsd-manager.c
new file mode 100644
index 0000000..b05c6e8
--- /dev/null
+++ b/src/mountfsd/mountfsd-manager.c
@@ -0,0 +1,277 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#include <sys/wait.h>
+
+#include "sd-daemon.h"
+
+#include "build-path.h"
+#include "common-signal.h"
+#include "env-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "mkdir.h"
+#include "mountfsd-manager.h"
+#include "process-util.h"
+#include "set.h"
+#include "signal-util.h"
+#include "socket-util.h"
+#include "stdio-util.h"
+#include "umask-util.h"
+
+#define LISTEN_TIMEOUT_USEC (25 * USEC_PER_SEC)
+
+static int start_workers(Manager *m, bool explicit_request);
+
+static size_t manager_current_workers(Manager *m) {
+        assert(m);
+
+        return set_size(m->workers_fixed) + set_size(m->workers_dynamic);
+}
+
+static int on_worker_exit(sd_event_source *s, const siginfo_t *si, void *userdata) {
+        Manager *m = ASSERT_PTR(userdata);
+
+        assert(s);
+
+        assert_se(!set_remove(m->workers_dynamic, s) != !set_remove(m->workers_fixed, s));
+        sd_event_source_disable_unref(s);
+
+        if (si->si_code == CLD_EXITED) {
+                if (si->si_status == EXIT_SUCCESS)
+                        log_debug("Worker " PID_FMT " exited successfully.", si->si_pid);
+                else
+                        log_warning("Worker " PID_FMT " died with a failure exit status %i, ignoring.", si->si_pid, si->si_status);
+        } else if (si->si_code == CLD_KILLED)
+                log_warning("Worker " 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_warning("Worker " PID_FMT " dumped core by signal %s, ignoring.", si->si_pid, signal_to_string(si->si_status));
+        else
+                log_warning("Got unexpected exit code via SIGCHLD, ignoring.");
+
+        (void) start_workers(m, /* explicit_request= */ 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 = ASSERT_PTR(userdata);
+
+        (void) start_workers(m, /* explicit_request= */ 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;
+}
+
+DEFINE_PRIVATE_HASH_OPS_WITH_KEY_DESTRUCTOR(
+                event_source_hash_ops,
+                sd_event_source,
+                (void (*)(const sd_event_source*, struct siphash*)) trivial_hash_func,
+                (int (*)(const sd_event_source*, const sd_event_source*)) trivial_compare_func,
+                sd_event_source_disable_unref);
+
+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 = -EBADF,
+                .worker_ratelimit = {
+                        .interval = 5 * USEC_PER_SEC,
+                        .burst = 50,
+                },
+        };
+
+        r = sd_event_new(&m->event);
+        if (r < 0)
+                return r;
+
+        r = sd_event_set_signal_exit(m->event, true);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_signal(m->event, NULL, (SIGRTMIN+18)|SD_EVENT_SIGNAL_PROCMASK, sigrtmin18_handler, NULL);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_memory_pressure(m->event, NULL, NULL, NULL);
+        if (r < 0)
+                log_debug_errno(r, "Failed allocate memory pressure event source, ignoring: %m");
+
+        r = sd_event_set_watchdog(m->event, true);
+        if (r < 0)
+                log_debug_errno(r, "Failed to enable watchdog handling, ignoring: %m");
+
+        r = sd_event_add_signal(m->event, NULL, SIGUSR2|SD_EVENT_SIGNAL_PROCMASK, on_sigusr2, 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);
+
+        /* Note: we rely on PR_DEATHSIG to kill the workers for us */
+
+        sd_event_unref(m->event);
+
+        return mfree(m);
+}
+
+static int start_one_worker(Manager *m) {
+        _cleanup_(sd_event_source_disable_unrefp) sd_event_source *source = NULL;
+        bool fixed;
+        pid_t pid;
+        int r;
+
+        assert(m);
+
+        fixed = set_size(m->workers_fixed) < MOUNTFS_WORKERS_MIN;
+
+        r = safe_fork_full(
+                        "(sd-worker)",
+                        /* stdio_fds= */ NULL,
+                        &m->listen_fd, 1,
+                        FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGTERM|FORK_REOPEN_LOG|FORK_LOG|FORK_CLOSE_ALL_FDS,
+                        &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 */
+
+                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("MOUNTFS_FIXED_WORKER", one_zero(fixed), 1) < 0) {
+                        log_error_errno(errno, "Failed to set $MOUNTFS_FIXED_WORKER: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                r = setenv_systemd_log_level();
+                if (r < 0) {
+                        log_error_errno(r, "Failed to set $SYSTEMD_LOG_LEVEL: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                r = invoke_callout_binary(SYSTEMD_MOUNTWORK_PATH, STRV_MAKE("systemd-mountwork", "xxxxxxxxxxxxxxxx")); /* With some extra space rename_process() can make use of */
+                log_error_errno(r, "Failed start worker process: %m");
+                _exit(EXIT_FAILURE);
+        }
+
+        r = sd_event_add_child(m->event, &source, pid, WEXITED, on_worker_exit, m);
+        if (r < 0)
+                return log_error_errno(r, "Failed to watch child " PID_FMT ": %m", pid);
+
+        r = set_ensure_put(
+                        fixed ? &m->workers_fixed : &m->workers_dynamic,
+                        &event_source_hash_ops,
+                        source);
+        if (r < 0)
+                return log_error_errno(r, "Failed to add child process to set: %m");
+
+        TAKE_PTR(source);
+
+        return 0;
+}
+
+static int start_workers(Manager *m, bool explicit_request) {
+        int r;
+
+        assert(m);
+
+        for (;;)  {
+                size_t n;
+
+                n = manager_current_workers(m);
+
+                log_debug("%zu workers running.", n);
+
+                if (n >= MOUNTFS_WORKERS_MIN && (!explicit_request || n >= MOUNTFS_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) {
+        int n;
+
+        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 {
+                static const union sockaddr_union sockaddr = {
+                        .un.sun_family = AF_UNIX,
+                        .un.sun_path = "/run/systemd/io.systemd.MountFileSystem",
+                };
+
+                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);
+
+                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");
+
+                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(LISTEN_TIMEOUT_USEC), sizeof(struct timeval)) < 0)
+                return log_error_errno(errno, "Failed to se SO_RCVTIMEO: %m");
+
+        return start_workers(m, /* explicit_request= */ false);
+}