repmgrd: basic code

errcode.h

@@ -11,6 +11,7 @@
 #define SUCCESS 0
 #define ERR_BAD_CONFIG 1
 #define ERR_BAD_RSYNC 2
+#define ERR_BAD_PIDFILE 3
 #define ERR_NO_RESTART 4
 #define ERR_DB_CONN 6
 #define ERR_DB_QUERY 7

repmgrd.c

@@ -9,12 +9,56 @@
 
 #include <stdio.h>
 
-static void do_help(void);
+#include <sys/stat.h>
+
+
+#define OPT_HELP						   1
+
+static char	   *config_file = NULL;
+static bool		verbose = false;
+static char	   *pid_file = NULL;
+static bool		daemonize = false;
+
+t_configuration_options config_file_options = T_CONFIGURATION_OPTIONS_INITIALIZER;
+
+static t_node_info local_node_info;
+
+static void show_help(void);
+static void show_usage(void);
+static void daemonize_process(void);
+static void check_and_create_pid_file(const char *pid_file);
 
 int
 main(int argc, char **argv)
 {
-	/* Disallow running as root to prevent directory ownership problems */
+	int			optindex;
+	int			c;
+	bool		monitoring_history = false;
+
+	static struct option long_options[] =
+	{
+/* general options */
+		{"help", no_argument, NULL, OPT_HELP},
+		{"version", no_argument, NULL, 'V'},
+
+/* configuration options */
+		{"config-file", required_argument, NULL, 'f'},
+
+/* daemon options */
+		{"daemonize", no_argument, NULL, 'd'},
+		{"pid-file", required_argument, NULL, 'p'},
+
+/* logging options */
+		{"verbose", no_argument, NULL, 'v'},
+
+/* legacy options */
+		{"monitoring-history", no_argument, NULL, 'm'},
+		{NULL, 0, NULL, 0}
+	};
+
+	set_progname(argv[0]);
+
+	/* Disallow running as root */
 	if (geteuid() == 0)
 	{
 		fprintf(stderr,
@@ -27,12 +71,250 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	do_help();
+	while ((c = getopt_long(argc, argv, "?Vf:vdp:m", long_options, &optindex)) != -1)
-	return 0;
+	{
+		switch (c)
+		{
+
+			/* general options */
+
+			case '?':
+				/* Actual help option given */
+				if (strcmp(argv[optind - 1], "-?") == 0)
+				{
+					show_help();
+					exit(SUCCESS);
+				}
+				/* unknown option reported by getopt */
+				goto unknown_option;
+				break;
+
+			case OPT_HELP:
+				show_help();
+				exit(SUCCESS);
+
+			case 'V':
+				/*
+				 * in contrast to repmgr3 and earlier, we only display the repmgr version
+				 * as it's not specific to a particular PostgreSQL version
+				 */
+				printf("%s %s\n", progname(), REPMGR_VERSION);
+				exit(SUCCESS);
+
+			/* configuration options */
+
+			case 'f':
+				config_file = optarg;
+				break;
+
+			/* daemon options */
+
+			case 'd':
+				daemonize = true;
+				break;
+
+			case 'p':
+				pid_file = optarg;
+				break;
+
+			/* logging options */
+
+			case 'v':
+				verbose = true;
+				break;
+
+			/* legacy options */
+
+			case 'm':
+				monitoring_history = true;
+				break;
+
+			default:
+     unknown_option:
+				show_usage();
+				exit(ERR_BAD_CONFIG);
+		}
+	}
+
+	/*
+	 * Tell the logger we're a daemon - this will ensure any output logged
+	 * before the logger is initialized will be formatted correctly
+	 */
+	logger_output_mode = OM_DAEMON;
+
+
+	/*
+	 * Parse the configuration file, if provided. If no configuration file
+	 * was provided, or one was but was incomplete, parse_config() will
+	 * abort anyway, with an appropriate message.
+	 */
+	load_config(config_file, verbose, false, &config_file_options, argv[0]);
+
+	/*
+	 * -m/--monitoring-history, if provided, will override repmgr.conf's
+	 * monitoring_history; this is for backwards compatibility as it's
+	 * possible this may be baked into various startup scripts.
+	 */
+
+	if (monitoring_history == true)
+	{
+		config_file_options.monitoring_history = true;
+	}
+
+	if (daemonize == true)
+	{
+		daemonize_process();
+	}
+
+	if (pid_file != NULL)
+	{
+		check_and_create_pid_file(pid_file);
+	}
+
+	while(1) {
+		sleep(1);
+	}
+	/* shut down logging system */
+	logger_shutdown();
+
+	return SUCCESS;
+}
+
+
+static void
+daemonize_process(void)
+{
+	char	   *ptr,
+				path[MAXLEN];
+	pid_t		pid = fork();
+	int			ret;
+
+	switch (pid)
+	{
+		case -1:
+			log_error(_("error in fork():\n  %s"), strerror(errno));
+			exit(ERR_SYS_FAILURE);
+			break;
+
+		case 0:			/* child process */
+			pid = setsid();
+			if (pid == (pid_t) -1)
+			{
+				log_error(_("error in setsid():\n  %s"), strerror(errno));
+				exit(ERR_SYS_FAILURE);
+			}
+
+			/* ensure that we are no longer able to open a terminal */
+			pid = fork();
+
+			if (pid == -1)		/* error case */
+			{
+				log_error(_("error in fork():\n  %s"), strerror(errno));
+				exit(ERR_SYS_FAILURE);
+			}
+
+			if (pid != 0)		/* parent process */
+			{
+				exit(0);
+			}
+
+			/* a child just flows along */
+
+			memset(path, 0, MAXLEN);
+
+			for (ptr = config_file + strlen(config_file); ptr > config_file; --ptr)
+			{
+				if (*ptr == '/')
+				{
+					strncpy(path, config_file, ptr - config_file);
+				}
+			}
+
+			if (*path == '\0')
+			{
+				*path = '/';
+			}
+
+			ret = chdir(path);
+			if (ret != 0)
+			{
+				log_error(_("error changing directory to '%s':\n  %s"), path,
+						  strerror(errno));
+			}
+
+			break;
+
+		default:				/* parent process */
+			exit(0);
+	}
+}
+
+static void
+check_and_create_pid_file(const char *pid_file)
+{
+	struct stat st;
+	FILE	   *fd;
+	char		buff[MAXLEN];
+	pid_t		pid;
+	size_t		nread;
+
+	if (stat(pid_file, &st) != -1)
+	{
+		memset(buff, 0, MAXLEN);
+
+		fd = fopen(pid_file, "r");
+
+		if (fd == NULL)
+		{
+			log_error(_("PID file %s exists but could not opened for reading"), pid_file);
+			log_hint(_("if repmgrd is no longer alive, remove the file and restart repmgrd"));
+			exit(ERR_BAD_PIDFILE);
+		}
+
+		nread = fread(buff, MAXLEN - 1, 1, fd);
+
+		if (nread == 0 && ferror(fd))
+		{
+			log_error(_("error reading PID file '%s', aborting"), pid_file);
+			exit(ERR_BAD_PIDFILE);
+		}
+
+		fclose(fd);
+
+		pid = atoi(buff);
+
+		if (pid != 0)
+		{
+			if (kill(pid, 0) != -1)
+			{
+				log_error(_("PID file %s exists and seems to contain a valid PID"), pid_file);
+				log_hint(_("if repmgrd is no longer alive, remove the file and restart repmgrd"));
+				exit(ERR_BAD_PIDFILE);
+			}
+		}
+	}
+
+	fd = fopen(pid_file, "w");
+	if (fd == NULL)
+	{
+		log_error(_("could not open PID file %s"), pid_file);
+		exit(ERR_BAD_CONFIG);
+	}
+
+	fprintf(fd, "%d", getpid());
+	fclose(fd);
+}
+
+
+void
+show_usage(void)
+{
+	fprintf(stderr, _("%s: replication management daemon for PostgreSQL\n"), progname());
+	fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname());
 }
 
 void
-do_help(void)
+show_help(void)
 {
 	printf(_("%s: replication management daemon for PostgreSQL\n"), progname());
 	puts("");