diff options
| -rw-r--r-- | demo-json-rpc-server.c | 73 |
1 files changed, 56 insertions, 17 deletions
diff --git a/demo-json-rpc-server.c b/demo-json-rpc-server.c index 2e0b104..483f701 100644 --- a/demo-json-rpc-server.c +++ b/demo-json-rpc-server.c @@ -44,9 +44,7 @@ #include "http-parser/http_parser.h" -// --- Extensions to liberty --------------------------------------------------- - -// Currently in sync, nothing to be moved. +enum { PIPE_READ, PIPE_WRITE }; // --- libev helpers ----------------------------------------------------------- @@ -2430,21 +2428,21 @@ setup_listen_fds (struct server_context *ctx, struct error **e) return true; } -static bool -lock_pid_file (struct server_context *ctx, struct error **e) +static int +lock_pid_file (const char *path, struct error **e) { - const char *path = str_map_find (&ctx->config, "pid_file"); - if (!path) - return true; - + // When using XDG_RUNTIME_DIR, the file needs to either have its + // access time bumped every 6 hours, or have the sticky bit set int fd = open (path, O_RDWR | O_CREAT, - S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH /* 644 */); + S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH /* 644 */ | S_ISVTX /* sticky */); if (fd < 0) { error_set (e, "can't open `%s': %s", path, strerror (errno)); - return false; + return -1; } + set_cloexec (fd); + struct flock lock = { .l_type = F_WRLCK, @@ -2455,7 +2453,8 @@ lock_pid_file (struct server_context *ctx, struct error **e) if (fcntl (fd, F_SETLK, &lock)) { error_set (e, "can't lock `%s': %s", path, strerror (errno)); - return false; + xclose (fd); + return -1; } struct str pid; @@ -2466,13 +2465,27 @@ lock_pid_file (struct server_context *ctx, struct error **e) || write (fd, pid.str, pid.len) != (ssize_t) pid.len) { error_set (e, "can't write to `%s': %s", path, strerror (errno)); - return false; + xclose (fd); + return -1; } str_free (&pid); // Intentionally not closing the file descriptor; it must stay alive // for the entire life of the application - return true; + return fd; +} + +static bool +app_lock_pid_file (struct server_context *ctx, struct error **e) +{ + const char *path = str_map_find (&ctx->config, "pid_file"); + if (!path) + return true; + + char *resolved = resolve_filename (path, resolve_relative_runtime_filename); + bool result = lock_pid_file (resolved, e) != -1; + free (resolved); + return result; } // --- Tests ------------------------------------------------------------------- @@ -2517,18 +2530,34 @@ on_termination_signal (EV_P_ ev_signal *handle, int revents) } static void -daemonize (void) +daemonize (struct server_context *ctx) { print_status ("daemonizing..."); if (chdir ("/")) exit_fatal ("%s: %s", "chdir", strerror (errno)); + // Because of systemd, we need to exit the parent process _after_ writing + // a PID file, otherwise our grandchild would receive a SIGTERM + int sync_pipe[2]; + if (pipe (sync_pipe)) + exit_fatal ("%s: %s", "pipe", strerror (errno)); + pid_t pid; if ((pid = fork ()) < 0) exit_fatal ("%s: %s", "fork", strerror (errno)); else if (pid) + { + // Wait until all write ends of the pipe are closed, which can mean + // either success or failure, we don't need to care + xclose (sync_pipe[PIPE_WRITE]); + + char dummy; + if (read (sync_pipe[PIPE_READ], &dummy, 1) < 0) + exit_fatal ("%s: %s", "read", strerror (errno)); + exit (EXIT_SUCCESS); + } setsid (); signal (SIGHUP, SIG_IGN); @@ -2541,6 +2570,15 @@ daemonize (void) openlog (PROGRAM_NAME, LOG_NDELAY | LOG_NOWAIT | LOG_PID, 0); g_log_message_real = log_message_syslog; + // Write the PID file (if so configured) and get rid of the pipe, so that + // the read() in our grandparent finally returns zero (no write ends) + struct error *e = NULL; + if (!app_lock_pid_file (ctx, &e)) + exit_fatal ("%s", e->message); + + xclose (sync_pipe[PIPE_READ]); + xclose (sync_pipe[PIPE_WRITE]); + // XXX: we may close our own descriptors this way, crippling ourselves; // there is no real guarantee that we will start with all three // descriptors open. In theory we could try to enumerate the descriptors @@ -2643,7 +2681,6 @@ main (int argc, char *argv[]) LIST_PREPEND (ctx.handlers, &g_request_handler_json_rpc); if (!parse_config (&ctx, &e) - || !lock_pid_file (&ctx, &e) || !setup_listen_fds (&ctx, &e)) { print_error ("%s", e->message); @@ -2652,7 +2689,9 @@ main (int argc, char *argv[]) } if (!g_debug_mode) - daemonize (); + daemonize (&ctx); + else if (!app_lock_pid_file (&ctx, &e)) + exit_fatal ("%s", e->message); ev_run (loop, 0); ev_loop_destroy (loop); |