diff options
| -rw-r--r-- | README.md | 1 | ||||
| -rw-r--r-- | main.c | 21 |
2 files changed, 18 insertions, 4 deletions
diff --git a/README.md b/README.md index 79ef13a..5c0f6cf 100644 --- a/README.md +++ b/README.md @@ -66,6 +66,7 @@ Reference](#collector-reference) section. | Flag | Description | | ---- | ----------- | | `--foreground` | Don't daemonize, but remain on the foreground instead. | +| `--pidfile=F` | After daemonizing, write the PID of the process to file at *F*. No effect if combined with `--foreground`. | | `--port=X` | Listen on port *X* instead of the default port (9100). | ## Collector Reference diff --git a/main.c b/main.c index 43acbcb..9bfc8ea 100644 --- a/main.c +++ b/main.c @@ -35,11 +35,13 @@ enum tristate { flag_off = -1, flag_undef = 0, flag_on = 1 }; struct config { const char *port; bool daemonize; + const char *pidfile; }; const struct config default_config = { .port = "9100", .daemonize = true, + .pidfile = 0, }; struct handler_ctx { @@ -53,7 +55,7 @@ struct handler_ctx { static bool parse_args(int argc, char *argv[], struct config *cfg, struct handler_ctx *ctx); static bool initialize(struct handler_ctx *ctx, int max_args); -static bool daemonize(void); +static bool daemonize(struct config *cfg); static void handler(scrape_req *req, void *ctx_ptr); int main(int argc, char *argv[]) { @@ -70,7 +72,7 @@ int main(int argc, char *argv[]) { return 1; if (cfg.daemonize) - if (!daemonize()) + if (!daemonize(&cfg)) return 1; scrape_serve(server, handler, &ctx); @@ -121,6 +123,9 @@ static bool parse_args(int argc, char *argv[], struct config *cfg, struct handle } else if (strcmp(argv[arg], "--foreground") == 0) { cfg->daemonize = false; goto next_arg; + } else if (strncmp(argv[arg], "--pidfile=", 10) == 0) { + cfg->pidfile = &argv[arg][10]; + goto next_arg; } fprintf(stderr, "unknown argument: %s\n", argv[arg]); @@ -158,7 +163,7 @@ static bool initialize(struct handler_ctx *ctx, int max_args) { return true; } -static bool daemonize(void) { +static bool daemonize(struct config *cfg) { pid_t pid; pid = fork(); @@ -198,7 +203,15 @@ static bool daemonize(void) { else if (pid > 0) exit(0); // lets the parent know all is well - // in the grandchild, continue execution + // attempt to record the grandchild PID, if asked to + + if (cfg->pidfile) { + FILE *f = fopen(cfg->pidfile, "w"); + if (f) { + fprintf(f, "%ld\n", (long) getpid()); + fclose(f); + } + } return true; } |