diff options
Diffstat (limited to 'src/userdb/userdbd-manager.c')
| -rw-r--r-- | src/userdb/userdbd-manager.c | 301 |
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); +} |