text: /*-------------------------------------------------------------------------
   *
   * pg_receivexlog.c - receive streaming transaction log data and write it
   *					  to a local file.
   *
   * Author: Magnus Hagander <magnus@hagander.net>
   *
   * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
   *
   * IDENTIFICATION
   *		  src/bin/pg_basebackup/pg_receivexlog.c
   *-------------------------------------------------------------------------
   */
  
  #include "postgres_fe.h"
  
  #include <dirent.h>
  #include <signal.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <unistd.h>
  
  #include "libpq-fe.h"
  #include "access/xlog_internal.h"
  #include "getopt_long.h"
  
  #include "receivelog.h"
  #include "streamutil.h"
  
  
  /* Time to sleep between reconnection attempts */
  #define RECONNECT_SLEEP_TIME 5
  
  /* Global options */
  static char *basedir = NULL;
  static int	verbose = 0;
  static int	noloop = 0;
  static int	standby_message_timeout = 10 * 1000;		/* 10 sec = default */
  static volatile bool time_to_abort = false;
  
  
  static void usage(void);
  static XLogRecPtr FindStreamingStart(uint32 *tli);
  static void StreamLog();
  static bool stop_streaming(XLogRecPtr segendpos, uint32 timeline,
  			   bool segment_finished);
  
  #define disconnect_and_exit(code)				\
  	{											\
  	if (conn != NULL) PQfinish(conn);			\
  	exit(code);									\
  	}
  
  
  static void
  usage(void)
  {
  	printf(_("%s receives PostgreSQL streaming transaction logs.\n\n"),
  		   progname);
  	printf(_("Usage:\n"));
  	printf(_("  %s [OPTION]...\n"), progname);
  	printf(_("\nOptions:\n"));
  	printf(_("  -D, --directory=DIR    receive transaction log files into this directory\n"));
  	printf(_("  -n, --no-loop          do not loop on connection lost\n"));
  	printf(_("  -v, --verbose          output verbose messages\n"));
  	printf(_("  -V, --version          output version information, then exit\n"));
  	printf(_("  -?, --help             show this help, then exit\n"));
  	printf(_("\nConnection options:\n"));
  	printf(_("  -d, --dbname=CONNSTR   connection string\n"));
  	printf(_("  -h, --host=HOSTNAME    database server host or socket directory\n"));
  	printf(_("  -p, --port=PORT        database server port number\n"));
  	printf(_("  -s, --status-interval=INTERVAL\n"
  			 "                         time between status packets sent to server (in seconds)\n"));
  	printf(_("  -U, --username=NAME    connect as specified database user\n"));
  	printf(_("  -w, --no-password      never prompt for password\n"));
  	printf(_("  -W, --password         force password prompt (should happen automatically)\n"));
  	printf(_("      --slot             replication slot to use\n"));
  	printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));
  }
  
  static bool
  stop_streaming(XLogRecPtr xlogpos, uint32 timeline, bool segment_finished)
  {
  	static uint32 prevtimeline = 0;
  	static XLogRecPtr prevpos = InvalidXLogRecPtr;
  
  	/* we assume that we get called once at the end of each segment */
  	if (verbose && segment_finished)
  		fprintf(stderr, _("%s: finished segment at %X/%X (timeline %u)\n"),
  				progname, (uint32) (xlogpos >> 32), (uint32) xlogpos,
  				timeline);
  
  	/*
  	 * Note that we report the previous, not current, position here. After a
  	 * timeline switch, xlogpos points to the beginning of the segment because
  	 * that's where we always begin streaming. Reporting the end of previous
  	 * timeline isn't totally accurate, because the next timeline can begin
  	 * slightly before the end of the WAL that we received on the previous
  	 * timeline, but it's close enough for reporting purposes.
  	 */
  	if (prevtimeline != 0 && prevtimeline != timeline)
  		fprintf(stderr, _("%s: switched to timeline %u at %X/%X\n"),
  				progname, timeline,
  				(uint32) (prevpos >> 32), (uint32) prevpos);
  
  	prevtimeline = timeline;
  	prevpos = xlogpos;
  
  	if (time_to_abort)
  	{
  		fprintf(stderr, _("%s: received interrupt signal, exiting\n"),
  				progname);
  		return true;
  	}
  	return false;
  }
  
  /*
   * Determine starting location for streaming, based on any existing xlog
   * segments in the directory. We start at the end of the last one that is
   * complete (size matches XLogSegSize), on the timeline with highest ID.
   *
   * If there are no WAL files in the directory, returns InvalidXLogRecPtr.
   */
  static XLogRecPtr
  FindStreamingStart(uint32 *tli)
  {
  	DIR		   *dir;
  	struct dirent *dirent;
  	XLogSegNo	high_segno = 0;
  	uint32		high_tli = 0;
  	bool		high_ispartial = false;
  
  	dir = opendir(basedir);
  	if (dir == NULL)
  	{
  		fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
  				progname, basedir, strerror(errno));
  		disconnect_and_exit(1);
  	}
  
  	while ((dirent = readdir(dir)) != NULL)
  	{
  		uint32		tli;
  		XLogSegNo	segno;
  		bool		ispartial;
  
  		/*
  		 * Check if the filename looks like an xlog file, or a .partial file.
  		 * Xlog files are always 24 characters, and .partial files are 32
  		 * characters.
  		 */
  		if (strlen(dirent->d_name) == 24)
  		{
  			if (strspn(dirent->d_name, "0123456789ABCDEF") != 24)
  				continue;
  			ispartial = false;
  		}
  		else if (strlen(dirent->d_name) == 32)
  		{
  			if (strspn(dirent->d_name, "0123456789ABCDEF") != 24)
  				continue;
  			if (strcmp(&dirent->d_name[24], ".partial") != 0)
  				continue;
  			ispartial = true;
  		}
  		else
  			continue;
  
  		/*
  		 * Looks like an xlog file. Parse its position.
  		 */
  		XLogFromFileName(dirent->d_name, &tli, &segno);
  
  		/*
  		 * Check that the segment has the right size, if it's supposed to be
  		 * completed.
  		 */
  		if (!ispartial)
  		{
  			struct stat statbuf;
  			char		fullpath[MAXPGPATH];
  
  			snprintf(fullpath, sizeof(fullpath), "%s/%s", basedir, dirent->d_name);
  			if (stat(fullpath, &statbuf) != 0)
  			{
  				fprintf(stderr, _("%s: could not stat file \"%s\": %s\n"),
  						progname, fullpath, strerror(errno));
  				disconnect_and_exit(1);
  			}
  
  			if (statbuf.st_size != XLOG_SEG_SIZE)
  			{
  				fprintf(stderr,
  						_("%s: segment file \"%s\" has incorrect size %d, skipping\n"),
  						progname, dirent->d_name, (int) statbuf.st_size);
  				continue;
  			}
  		}
  
  		/* Looks like a valid segment. Remember that we saw it. */
  		if ((segno > high_segno) ||
  			(segno == high_segno && tli > high_tli) ||
  			(segno == high_segno && tli == high_tli && high_ispartial && !ispartial))
  		{
  			high_segno = segno;
  			high_tli = tli;
  			high_ispartial = ispartial;
  		}
  	}
  
  	closedir(dir);
  
  	if (high_segno > 0)
  	{
  		XLogRecPtr	high_ptr;
  
  		/*
  		 * Move the starting pointer to the start of the next segment, if
  		 * the highest one we saw was completed. Otherwise start streaming
  		 * from the beginning of the .partial segment.
  		 */
  		if (!high_ispartial)
  			high_segno++;
  
  		XLogSegNoOffsetToRecPtr(high_segno, 0, high_ptr);
  
  		*tli = high_tli;
  		return high_ptr;
  	}
  	else
  		return InvalidXLogRecPtr;
  }
  
  /*
   * Start the log streaming
   */
  static void
  StreamLog(void)
  {
  	PGresult   *res;
  	XLogRecPtr	startpos;
  	uint32		starttli;
  	XLogRecPtr	serverpos;
  	uint32		servertli;
  	uint32		hi,
  				lo;
  
  	/*
  	 * Connect in replication mode to the server
  	 */
  	conn = GetConnection();
  	if (!conn)
  		/* Error message already written in GetConnection() */
  		return;
  
  	if (!CheckServerVersionForStreaming(conn))
  	{
  		/*
  		 * Error message already written in CheckServerVersionForStreaming().
  		 * There's no hope of recovering from a version mismatch, so don't
  		 * retry.
  		 */
  		disconnect_and_exit(1);
  	}
  
  	/*
  	 * Run IDENTIFY_SYSTEM so we can get the timeline and current xlog
  	 * position.
  	 */
  	res = PQexec(conn, "IDENTIFY_SYSTEM");
  	if (PQresultStatus(res) != PGRES_TUPLES_OK)
  	{
  		fprintf(stderr, _("%s: could not send replication command \"%s\": %s"),
  				progname, "IDENTIFY_SYSTEM", PQerrorMessage(conn));
  		disconnect_and_exit(1);
  	}
  	if (PQntuples(res) != 1 || PQnfields(res) != 3)
  	{
  		fprintf(stderr,
  				_("%s: could not identify system: got %d rows and %d fields, expected %d rows and %d fields\n"),
  				progname, PQntuples(res), PQnfields(res), 1, 3);
  		disconnect_and_exit(1);
  	}
  	servertli = atoi(PQgetvalue(res, 0, 1));
  	if (sscanf(PQgetvalue(res, 0, 2), "%X/%X", &hi, &lo) != 2)
  	{
  		fprintf(stderr,
  				_("%s: could not parse transaction log location \"%s\"\n"),
  				progname, PQgetvalue(res, 0, 2));
  		disconnect_and_exit(1);
  	}
  	serverpos = ((uint64) hi) << 32 | lo;
  	PQclear(res);
  
  	/*
  	 * Figure out where to start streaming.
  	 */
  	startpos = FindStreamingStart(&starttli);
  	if (startpos == InvalidXLogRecPtr)
  	{
  		startpos = serverpos;
  		starttli = servertli;
  	}
  
  	/*
  	 * Always start streaming at the beginning of a segment
  	 */
  	startpos -= startpos % XLOG_SEG_SIZE;
  
  	/*
  	 * Start the replication
  	 */
  	if (verbose)
  		fprintf(stderr,
  				_("%s: starting log streaming at %X/%X (timeline %u)\n"),
  				progname, (uint32) (startpos >> 32), (uint32) startpos,
  				starttli);
  
  	ReceiveXlogStream(conn, startpos, starttli, NULL, basedir,
  					  stop_streaming, standby_message_timeout, ".partial");
  
  	PQfinish(conn);
  }
  
  /*
   * When sigint is called, just tell the system to exit at the next possible
   * moment.
   */
  #ifndef WIN32
  
  static void
  sigint_handler(int signum)
  {
  	time_to_abort = true;
  }
  #endif
  
  int
  main(int argc, char **argv)
  {
  	static struct option long_options[] = {
  		{"help", no_argument, NULL, '?'},
  		{"version", no_argument, NULL, 'V'},
  		{"directory", required_argument, NULL, 'D'},
  		{"dbname", required_argument, NULL, 'd'},
  		{"host", required_argument, NULL, 'h'},
  		{"port", required_argument, NULL, 'p'},
  		{"username", required_argument, NULL, 'U'},
  		{"no-loop", no_argument, NULL, 'n'},
  		{"no-password", no_argument, NULL, 'w'},
  		{"password", no_argument, NULL, 'W'},
  		{"status-interval", required_argument, NULL, 's'},
  		{"slot", required_argument, NULL, 'S'},
  		{"verbose", no_argument, NULL, 'v'},
  		{NULL, 0, NULL, 0}
  	};
  
  	int			c;
  	int			option_index;
  
  	progname = get_progname(argv[0]);
  	set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_receivexlog"));
  
  	if (argc > 1)
  	{
  		if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
  		{
  			usage();
  			exit(0);
  		}
  		else if (strcmp(argv[1], "-V") == 0 ||
  				 strcmp(argv[1], "--version") == 0)
  		{
  			puts("pg_receivexlog (PostgreSQL) " PG_VERSION);
  			exit(0);
  		}
  	}
  
  	while ((c = getopt_long(argc, argv, "D:d:h:p:U:s:nwWv",
  							long_options, &option_index)) != -1)
  	{
  		switch (c)
  		{
  			case 'D':
  				basedir = pg_strdup(optarg);
  				break;
  			case 'd':
  				connection_string = pg_strdup(optarg);
  				break;
  			case 'h':
  				dbhost = pg_strdup(optarg);
  				break;
  			case 'p':
  				if (atoi(optarg) <= 0)
  				{
  					fprintf(stderr, _("%s: invalid port number \"%s\"\n"),
  							progname, optarg);
  					exit(1);
  				}
  				dbport = pg_strdup(optarg);
  				break;
  			case 'U':
  				dbuser = pg_strdup(optarg);
  				break;
  			case 'w':
  				dbgetpassword = -1;
  				break;
  			case 'W':
  				dbgetpassword = 1;
  				break;
  			case 's':
  				standby_message_timeout = atoi(optarg) * 1000;
  				if (standby_message_timeout < 0)
  				{
  					fprintf(stderr, _("%s: invalid status interval \"%s\"\n"),
  							progname, optarg);
  					exit(1);
  				}
  				break;
  			case 'S':
  				replication_slot = pg_strdup(optarg);
  				break;
  			case 'n':
  				noloop = 1;
  				break;
  			case 'v':
  				verbose++;
  				break;
  			default:
  
  				/*
  				 * getopt_long already emitted a complaint
  				 */
  				fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
  						progname);
  				exit(1);
  		}
  	}
  
  	/*
  	 * Any non-option arguments?
  	 */
  	if (optind < argc)
  	{
  		fprintf(stderr,
  				_("%s: too many command-line arguments (first is \"%s\")\n"),
  				progname, argv[optind]);
  		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
  				progname);
  		exit(1);
  	}
  
  	/*
  	 * Required arguments
  	 */
  	if (basedir == NULL)
  	{
  		fprintf(stderr, _("%s: no target directory specified\n"), progname);
  		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
  				progname);
  		exit(1);
  	}
  
  #ifndef WIN32
  	pqsignal(SIGINT, sigint_handler);
  #endif
  
  	while (true)
  	{
  		StreamLog();
  		if (time_to_abort)
  		{
  			/*
  			 * We've been Ctrl-C'ed. That's not an error, so exit without an
  			 * errorcode.
  			 */
  			exit(0);
  		}
  		else if (noloop)
  		{
  			fprintf(stderr, _("%s: disconnected\n"), progname);
  			exit(1);
  		}
  		else
  		{
  			fprintf(stderr,
  			/* translator: check source for value for %d */
  					_("%s: disconnected; waiting %d seconds to try again\n"),
  					progname, RECONNECT_SLEEP_TIME);
  			pg_usleep(RECONNECT_SLEEP_TIME * 1000000);
  		}
  	}
  }
  