pg_basebackup.c

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/*-------------------------------------------------------------------------
 *
 * pg_basebackup.c - receive a base backup using streaming replication protocol
 *
 * Author: Magnus Hagander <[email protected]>
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *        src/bin/pg_basebackup/pg_basebackup.c
 *-------------------------------------------------------------------------
 */

#include "postgres_fe.h"
#include "libpq-fe.h"
#include "pqexpbuffer.h"
#include "pgtar.h"

#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>

#ifdef HAVE_LIBZ
#include <zlib.h>
#endif

#include "getopt_long.h"

#include "receivelog.h"
#include "streamutil.h"


/* Global options */
char       *basedir = NULL;
char        format = 'p';       /* p(lain)/t(ar) */
char       *label = "pg_basebackup base backup";
bool        showprogress = false;
int         verbose = 0;
int         compresslevel = 0;
bool        includewal = false;
bool        streamwal = false;
bool        fastcheckpoint = false;
bool        writerecoveryconf = false;
int         standby_message_timeout = 10 * 1000;        /* 10 sec = default */

/* Progress counters */
static uint64 totalsize;
static uint64 totaldone;
static int  tablespacecount;

/* Pipe to communicate with background wal receiver process */
#ifndef WIN32
static int  bgpipe[2] = {-1, -1};
#endif

/* Handle to child process */
static pid_t bgchild = -1;

/* End position for xlog streaming, empty string if unknown yet */
static XLogRecPtr xlogendptr;

#ifndef WIN32
static int  has_xlogendptr = 0;
#else
static volatile LONG has_xlogendptr = 0;
#endif

/* Contents of recovery.conf to be generated */
static PQExpBuffer recoveryconfcontents = NULL;

/* Function headers */
static void usage(void);
static void verify_dir_is_empty_or_create(char *dirname);
static void progress_report(int tablespacenum, const char *filename);

static void ReceiveTarFile(PGconn *conn, PGresult *res, int rownum);
static void ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum);
static void GenerateRecoveryConf(PGconn *conn);
static void WriteRecoveryConf(void);
static void BaseBackup(void);

static bool reached_end_position(XLogRecPtr segendpos, uint32 timeline,
                     bool segment_finished);

#ifdef HAVE_LIBZ
static const char *
get_gz_error(gzFile gzf)
{
    int         errnum;
    const char *errmsg;

    errmsg = gzerror(gzf, &errnum);
    if (errnum == Z_ERRNO)
        return strerror(errno);
    else
        return errmsg;
}
#endif

static void
usage(void)
{
    printf(_("%s takes a base backup of a running PostgreSQL server.\n\n"),
           progname);
    printf(_("Usage:\n"));
    printf(_("  %s [OPTION]...\n"), progname);
    printf(_("\nOptions controlling the output:\n"));
    printf(_("  -D, --pgdata=DIRECTORY receive base backup into directory\n"));
    printf(_("  -F, --format=p|t       output format (plain (default), tar)\n"));
    printf(_("  -R, --write-recovery-conf\n"
             "                         write recovery.conf after backup\n"));
    printf(_("  -x, --xlog             include required WAL files in backup (fetch mode)\n"));
    printf(_("  -X, --xlog-method=fetch|stream\n"
             "                         include required WAL files with specified method\n"));
    printf(_("  -z, --gzip             compress tar output\n"));
    printf(_("  -Z, --compress=0-9     compress tar output with given compression level\n"));
    printf(_("\nGeneral options:\n"));
    printf(_("  -c, --checkpoint=fast|spread\n"
             "                         set fast or spread checkpointing\n"));
    printf(_("  -l, --label=LABEL      set backup label\n"));
    printf(_("  -P, --progress         show progress information\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(_("\nReport bugs to <[email protected]>.\n"));
}


/*
 * Called in the background process every time data is received.
 * On Unix, we check to see if there is any data on our pipe
 * (which would mean we have a stop position), and if it is, check if
 * it is time to stop.
 * On Windows, we are in a single process, so we can just check if it's
 * time to stop.
 */
static bool
reached_end_position(XLogRecPtr segendpos, uint32 timeline,
                     bool segment_finished)
{
    if (!has_xlogendptr)
    {
#ifndef WIN32
        fd_set      fds;
        struct timeval tv;
        int         r;

        /*
         * Don't have the end pointer yet - check our pipe to see if it has
         * been sent yet.
         */
        FD_ZERO(&fds);
        FD_SET(bgpipe[0], &fds);

        MemSet(&tv, 0, sizeof(tv));

        r = select(bgpipe[0] + 1, &fds, NULL, NULL, &tv);
        if (r == 1)
        {
            char        xlogend[64];
            uint32      hi,
                        lo;

            MemSet(xlogend, 0, sizeof(xlogend));
            r = read(bgpipe[0], xlogend, sizeof(xlogend));
            if (r < 0)
            {
                fprintf(stderr, _("%s: could not read from ready pipe: %s\n"),
                        progname, strerror(errno));
                exit(1);
            }

            if (sscanf(xlogend, "%X/%X", &hi, &lo) != 2)
            {
                fprintf(stderr,
                  _("%s: could not parse transaction log location \"%s\"\n"),
                        progname, xlogend);
                exit(1);
            }
            xlogendptr = ((uint64) hi) << 32 | lo;
            has_xlogendptr = 1;

            /*
             * Fall through to check if we've reached the point further
             * already.
             */
        }
        else
        {
            /*
             * No data received on the pipe means we don't know the end
             * position yet - so just say it's not time to stop yet.
             */
            return false;
        }
#else

        /*
         * On win32, has_xlogendptr is set by the main thread, so if it's not
         * set here, we just go back and wait until it shows up.
         */
        return false;
#endif
    }

    /*
     * At this point we have an end pointer, so compare it to the current
     * position to figure out if it's time to stop.
     */
    if (segendpos >= xlogendptr)
        return true;

    /*
     * Have end pointer, but haven't reached it yet - so tell the caller to
     * keep streaming.
     */
    return false;
}

typedef struct
{
    PGconn     *bgconn;
    XLogRecPtr  startptr;
    char        xlogdir[MAXPGPATH];
    char       *sysidentifier;
    int         timeline;
} logstreamer_param;

static int
LogStreamerMain(logstreamer_param *param)
{
    if (!ReceiveXlogStream(param->bgconn, param->startptr, param->timeline,
                           param->sysidentifier, param->xlogdir,
                           reached_end_position, standby_message_timeout,
                           NULL))

        /*
         * Any errors will already have been reported in the function process,
         * but we need to tell the parent that we didn't shutdown in a nice
         * way.
         */
        return 1;

    PQfinish(param->bgconn);
    return 0;
}

/*
 * Initiate background process for receiving xlog during the backup.
 * The background stream will use its own database connection so we can
 * stream the logfile in parallel with the backups.
 */
static void
StartLogStreamer(char *startpos, uint32 timeline, char *sysidentifier)
{
    logstreamer_param *param;
    uint32      hi,
                lo;

    param = pg_malloc0(sizeof(logstreamer_param));
    param->timeline = timeline;
    param->sysidentifier = sysidentifier;

    /* Convert the starting position */
    if (sscanf(startpos, "%X/%X", &hi, &lo) != 2)
    {
        fprintf(stderr,
                _("%s: could not parse transaction log location \"%s\"\n"),
                progname, startpos);
        disconnect_and_exit(1);
    }
    param->startptr = ((uint64) hi) << 32 | lo;
    /* Round off to even segment position */
    param->startptr -= param->startptr % XLOG_SEG_SIZE;

#ifndef WIN32
    /* Create our background pipe */
    if (pipe(bgpipe) < 0)
    {
        fprintf(stderr,
                _("%s: could not create pipe for background process: %s\n"),
                progname, strerror(errno));
        disconnect_and_exit(1);
    }
#endif

    /* Get a second connection */
    param->bgconn = GetConnection();
    if (!param->bgconn)
        /* Error message already written in GetConnection() */
        exit(1);

    /*
     * Always in plain format, so we can write to basedir/pg_xlog. But the
     * directory entry in the tar file may arrive later, so make sure it's
     * created before we start.
     */
    snprintf(param->xlogdir, sizeof(param->xlogdir), "%s/pg_xlog", basedir);
    verify_dir_is_empty_or_create(param->xlogdir);

    /*
     * Start a child process and tell it to start streaming. On Unix, this is
     * a fork(). On Windows, we create a thread.
     */
#ifndef WIN32
    bgchild = fork();
    if (bgchild == 0)
    {
        /* in child process */
        exit(LogStreamerMain(param));
    }
    else if (bgchild < 0)
    {
        fprintf(stderr, _("%s: could not create background process: %s\n"),
                progname, strerror(errno));
        disconnect_and_exit(1);
    }

    /*
     * Else we are in the parent process and all is well.
     */
#else                           /* WIN32 */
    bgchild = _beginthreadex(NULL, 0, (void *) LogStreamerMain, param, 0, NULL);
    if (bgchild == 0)
    {
        fprintf(stderr, _("%s: could not create background thread: %s\n"),
                progname, strerror(errno));
        disconnect_and_exit(1);
    }
#endif
}

/*
 * Verify that the given directory exists and is empty. If it does not
 * exist, it is created. If it exists but is not empty, an error will
 * be give and the process ended.
 */
static void
verify_dir_is_empty_or_create(char *dirname)
{
    switch (pg_check_dir(dirname))
    {
        case 0:

            /*
             * Does not exist, so create
             */
            if (pg_mkdir_p(dirname, S_IRWXU) == -1)
            {
                fprintf(stderr,
                        _("%s: could not create directory \"%s\": %s\n"),
                        progname, dirname, strerror(errno));
                disconnect_and_exit(1);
            }
            return;
        case 1:

            /*
             * Exists, empty
             */
            return;
        case 2:
        case 3:
        case 4:

            /*
             * Exists, not empty
             */
            fprintf(stderr,
                    _("%s: directory \"%s\" exists but is not empty\n"),
                    progname, dirname);
            disconnect_and_exit(1);
        case -1:

            /*
             * Access problem
             */
            fprintf(stderr, _("%s: could not access directory \"%s\": %s\n"),
                    progname, dirname, strerror(errno));
            disconnect_and_exit(1);
    }
}


/*
 * Print a progress report based on the global variables. If verbose output
 * is enabled, also print the current file name.
 */
static void
progress_report(int tablespacenum, const char *filename)
{
    int         percent = (int) ((totaldone / 1024) * 100 / totalsize);
    char        totaldone_str[32];
    char        totalsize_str[32];

    /*
     * Avoid overflowing past 100% or the full size. This may make the total
     * size number change as we approach the end of the backup (the estimate
     * will always be wrong if WAL is included), but that's better than having
     * the done column be bigger than the total.
     */
    if (percent > 100)
        percent = 100;
    if (totaldone / 1024 > totalsize)
        totalsize = totaldone / 1024;

    /*
     * Separate step to keep platform-dependent format code out of
     * translatable strings.  And we only test for INT64_FORMAT availability
     * in snprintf, not fprintf.
     */
    snprintf(totaldone_str, sizeof(totaldone_str), INT64_FORMAT,
             totaldone / 1024);
    snprintf(totalsize_str, sizeof(totalsize_str), INT64_FORMAT, totalsize);

#define VERBOSE_FILENAME_LENGTH 35
    if (verbose)
    {
        if (!filename)

            /*
             * No filename given, so clear the status line (used for last
             * call)
             */
            fprintf(stderr,
                    ngettext("%*s/%s kB (100%%), %d/%d tablespace %*s",
                             "%*s/%s kB (100%%), %d/%d tablespaces %*s",
                             tablespacecount),
                    (int) strlen(totalsize_str),
                    totaldone_str, totalsize_str,
                    tablespacenum, tablespacecount,
                    VERBOSE_FILENAME_LENGTH + 5, "");
        else
        {
            bool truncate = (strlen(filename) > VERBOSE_FILENAME_LENGTH);

            fprintf(stderr,
                    ngettext("%*s/%s kB (%d%%), %d/%d tablespace (%s%-*.*s)",
                             "%*s/%s kB (%d%%), %d/%d tablespaces (%s%-*.*s)",
                             tablespacecount),
                    (int) strlen(totalsize_str),
                    totaldone_str, totalsize_str, percent,
                    tablespacenum, tablespacecount,
                    /* Prefix with "..." if we do leading truncation */
                    truncate ? "..." : "",
                    truncate ? VERBOSE_FILENAME_LENGTH - 3 : VERBOSE_FILENAME_LENGTH,
                    truncate ? VERBOSE_FILENAME_LENGTH - 3 : VERBOSE_FILENAME_LENGTH,
                    /* Truncate filename at beginning if it's too long */
                    truncate ? filename + strlen(filename) - VERBOSE_FILENAME_LENGTH + 3 : filename);
        }
    }
    else
        fprintf(stderr,
                ngettext("%*s/%s kB (%d%%), %d/%d tablespace",
                         "%*s/%s kB (%d%%), %d/%d tablespaces",
                         tablespacecount),
                (int) strlen(totalsize_str),
                totaldone_str, totalsize_str, percent,
                tablespacenum, tablespacecount);

    fprintf(stderr, "\r");
}


/*
 * Write a piece of tar data
 */
static void
writeTarData(
#ifdef HAVE_LIBZ
             gzFile ztarfile,
#endif
             FILE *tarfile, char *buf, int r, char *current_file)
{
#ifdef HAVE_LIBZ
    if (ztarfile != NULL)
    {
        if (gzwrite(ztarfile, buf, r) != r)
        {
            fprintf(stderr,
                    _("%s: could not write to compressed file \"%s\": %s\n"),
                    progname, current_file, get_gz_error(ztarfile));
            disconnect_and_exit(1);
        }
    }
    else
#endif
    {
        if (fwrite(buf, r, 1, tarfile) != 1)
        {
            fprintf(stderr, _("%s: could not write to file \"%s\": %s\n"),
                    progname, current_file, strerror(errno));
            disconnect_and_exit(1);
        }
    }
}

#ifdef HAVE_LIBZ
#define WRITE_TAR_DATA(buf, sz) writeTarData(ztarfile, tarfile, buf, sz, filename)
#else
#define WRITE_TAR_DATA(buf, sz) writeTarData(tarfile, buf, sz, filename)
#endif

/*
 * Receive a tar format file from the connection to the server, and write
 * the data from this file directly into a tar file. If compression is
 * enabled, the data will be compressed while written to the file.
 *
 * The file will be named base.tar[.gz] if it's for the main data directory
 * or <tablespaceoid>.tar[.gz] if it's for another tablespace.
 *
 * No attempt to inspect or validate the contents of the file is done.
 */
static void
ReceiveTarFile(PGconn *conn, PGresult *res, int rownum)
{
    char        filename[MAXPGPATH];
    char       *copybuf = NULL;
    FILE       *tarfile = NULL;
    char        tarhdr[512];
    bool        basetablespace = PQgetisnull(res, rownum, 0);
    bool        in_tarhdr = true;
    bool        skip_file = false;
    size_t      tarhdrsz = 0;
    size_t      filesz = 0;

#ifdef HAVE_LIBZ
    gzFile      ztarfile = NULL;
#endif

    if (basetablespace)
    {
        /*
         * Base tablespaces
         */
        if (strcmp(basedir, "-") == 0)
        {
#ifdef HAVE_LIBZ
            if (compresslevel != 0)
            {
                ztarfile = gzdopen(dup(fileno(stdout)), "wb");
                if (gzsetparams(ztarfile, compresslevel,
                                Z_DEFAULT_STRATEGY) != Z_OK)
                {
                    fprintf(stderr,
                            _("%s: could not set compression level %d: %s\n"),
                            progname, compresslevel, get_gz_error(ztarfile));
                    disconnect_and_exit(1);
                }
            }
            else
#endif
                tarfile = stdout;
        }
        else
        {
#ifdef HAVE_LIBZ
            if (compresslevel != 0)
            {
                snprintf(filename, sizeof(filename), "%s/base.tar.gz", basedir);
                ztarfile = gzopen(filename, "wb");
                if (gzsetparams(ztarfile, compresslevel,
                                Z_DEFAULT_STRATEGY) != Z_OK)
                {
                    fprintf(stderr,
                            _("%s: could not set compression level %d: %s\n"),
                            progname, compresslevel, get_gz_error(ztarfile));
                    disconnect_and_exit(1);
                }
            }
            else
#endif
            {
                snprintf(filename, sizeof(filename), "%s/base.tar", basedir);
                tarfile = fopen(filename, "wb");
            }
        }
    }
    else
    {
        /*
         * Specific tablespace
         */
#ifdef HAVE_LIBZ
        if (compresslevel != 0)
        {
            snprintf(filename, sizeof(filename), "%s/%s.tar.gz", basedir,
                     PQgetvalue(res, rownum, 0));
            ztarfile = gzopen(filename, "wb");
            if (gzsetparams(ztarfile, compresslevel,
                            Z_DEFAULT_STRATEGY) != Z_OK)
            {
                fprintf(stderr,
                        _("%s: could not set compression level %d: %s\n"),
                        progname, compresslevel, get_gz_error(ztarfile));
                disconnect_and_exit(1);
            }
        }
        else
#endif
        {
            snprintf(filename, sizeof(filename), "%s/%s.tar", basedir,
                     PQgetvalue(res, rownum, 0));
            tarfile = fopen(filename, "wb");
        }
    }

#ifdef HAVE_LIBZ
    if (compresslevel != 0)
    {
        if (!ztarfile)
        {
            /* Compression is in use */
            fprintf(stderr,
                    _("%s: could not create compressed file \"%s\": %s\n"),
                    progname, filename, get_gz_error(ztarfile));
            disconnect_and_exit(1);
        }
    }
    else
#endif
    {
        /* Either no zlib support, or zlib support but compresslevel = 0 */
        if (!tarfile)
        {
            fprintf(stderr, _("%s: could not create file \"%s\": %s\n"),
                    progname, filename, strerror(errno));
            disconnect_and_exit(1);
        }
    }

    /*
     * Get the COPY data stream
     */
    res = PQgetResult(conn);
    if (PQresultStatus(res) != PGRES_COPY_OUT)
    {
        fprintf(stderr, _("%s: could not get COPY data stream: %s"),
                progname, PQerrorMessage(conn));
        disconnect_and_exit(1);
    }

    while (1)
    {
        int         r;

        if (copybuf != NULL)
        {
            PQfreemem(copybuf);
            copybuf = NULL;
        }

        r = PQgetCopyData(conn, &copybuf, 0);
        if (r == -1)
        {
            /*
             * End of chunk. If requested, and this is the base tablespace,
             * write recovery.conf into the tarfile. When done, close the file
             * (but not stdout).
             *
             * Also, write two completely empty blocks at the end of the tar
             * file, as required by some tar programs.
             */
            char        zerobuf[1024];

            MemSet(zerobuf, 0, sizeof(zerobuf));

            if (basetablespace && writerecoveryconf)
            {
                char        header[512];
                int         padding;

                tarCreateHeader(header, "recovery.conf", NULL,
                                recoveryconfcontents->len,
                                0600, 04000, 02000,
                                time(NULL));

                padding = ((recoveryconfcontents->len + 511) & ~511) - recoveryconfcontents->len;

                WRITE_TAR_DATA(header, sizeof(header));
                WRITE_TAR_DATA(recoveryconfcontents->data, recoveryconfcontents->len);
                if (padding)
                    WRITE_TAR_DATA(zerobuf, padding);
            }

            /* 2 * 512 bytes empty data at end of file */
            WRITE_TAR_DATA(zerobuf, sizeof(zerobuf));

#ifdef HAVE_LIBZ
            if (ztarfile != NULL)
            {
                if (gzclose(ztarfile) != 0)
                {
                    fprintf(stderr,
                       _("%s: could not close compressed file \"%s\": %s\n"),
                            progname, filename, get_gz_error(ztarfile));
                    disconnect_and_exit(1);
                }
            }
            else
#endif
            {
                if (strcmp(basedir, "-") != 0)
                {
                    if (fclose(tarfile) != 0)
                    {
                        fprintf(stderr,
                                _("%s: could not close file \"%s\": %s\n"),
                                progname, filename, strerror(errno));
                        disconnect_and_exit(1);
                    }
                }
            }

            break;
        }
        else if (r == -2)
        {
            fprintf(stderr, _("%s: could not read COPY data: %s"),
                    progname, PQerrorMessage(conn));
            disconnect_and_exit(1);
        }

        if (!writerecoveryconf || !basetablespace)
        {
            /*
             * When not writing recovery.conf, or when not working on the base
             * tablespace, we never have to look for an existing recovery.conf
             * file in the stream.
             */
            WRITE_TAR_DATA(copybuf, r);
        }
        else
        {
            /*
             * Look for a recovery.conf in the existing tar stream. If it's
             * there, we must skip it so we can later overwrite it with our
             * own version of the file.
             *
             * To do this, we have to process the individual files inside the
             * TAR stream. The stream consists of a header and zero or more
             * chunks, all 512 bytes long. The stream from the server is
             * broken up into smaller pieces, so we have to track the size of
             * the files to find the next header structure.
             */
            int         rr = r;
            int         pos = 0;

            while (rr > 0)
            {
                if (in_tarhdr)
                {
                    /*
                     * We're currently reading a header structure inside the
                     * TAR stream, i.e. the file metadata.
                     */
                    if (tarhdrsz < 512)
                    {
                        /*
                         * Copy the header structure into tarhdr in case the
                         * header is not aligned to 512 bytes or it's not
                         * returned in whole by the last PQgetCopyData call.
                         */
                        int         hdrleft;
                        int         bytes2copy;

                        hdrleft = 512 - tarhdrsz;
                        bytes2copy = (rr > hdrleft ? hdrleft : rr);

                        memcpy(&tarhdr[tarhdrsz], copybuf + pos, bytes2copy);

                        rr -= bytes2copy;
                        pos += bytes2copy;
                        tarhdrsz += bytes2copy;
                    }
                    else
                    {
                        /*
                         * We have the complete header structure in tarhdr,
                         * look at the file metadata: - the subsequent file
                         * contents have to be skipped if the filename is
                         * recovery.conf - find out the size of the file
                         * padded to the next multiple of 512
                         */
                        int         padding;

                        skip_file = (strcmp(&tarhdr[0], "recovery.conf") == 0);

                        sscanf(&tarhdr[124], "%11o", (unsigned int *) &filesz);

                        padding = ((filesz + 511) & ~511) - filesz;
                        filesz += padding;

                        /* Next part is the file, not the header */
                        in_tarhdr = false;

                        /*
                         * If we're not skipping the file, write the tar
                         * header unmodified.
                         */
                        if (!skip_file)
                            WRITE_TAR_DATA(tarhdr, 512);
                    }
                }
                else
                {
                    /*
                     * We're processing a file's contents.
                     */
                    if (filesz > 0)
                    {
                        /*
                         * We still have data to read (and possibly write).
                         */
                        int         bytes2write;

                        bytes2write = (filesz > rr ? rr : filesz);

                        if (!skip_file)
                            WRITE_TAR_DATA(copybuf + pos, bytes2write);

                        rr -= bytes2write;
                        pos += bytes2write;
                        filesz -= bytes2write;
                    }
                    else
                    {
                        /*
                         * No more data in the current file, the next piece of
                         * data (if any) will be a new file header structure.
                         */
                        in_tarhdr = true;
                        skip_file = false;
                        tarhdrsz = 0;
                        filesz = 0;
                    }
                }
            }
        }
        totaldone += r;
        if (showprogress)
            progress_report(rownum, filename);
    }                           /* while (1) */

    if (copybuf != NULL)
        PQfreemem(copybuf);
}

/*
 * Receive a tar format stream from the connection to the server, and unpack
 * the contents of it into a directory. Only files, directories and
 * symlinks are supported, no other kinds of special files.
 *
 * If the data is for the main data directory, it will be restored in the
 * specified directory. If it's for another tablespace, it will be restored
 * in the original directory, since relocation of tablespaces is not
 * supported.
 */
static void
ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum)
{
    char        current_path[MAXPGPATH];
    char        filename[MAXPGPATH];
    int         current_len_left;
    int         current_padding = 0;
    bool        basetablespace = PQgetisnull(res, rownum, 0);
    char       *copybuf = NULL;
    FILE       *file = NULL;

    if (basetablespace)
        strcpy(current_path, basedir);
    else
        strcpy(current_path, PQgetvalue(res, rownum, 1));

    /*
     * Get the COPY data
     */
    res = PQgetResult(conn);
    if (PQresultStatus(res) != PGRES_COPY_OUT)
    {
        fprintf(stderr, _("%s: could not get COPY data stream: %s"),
                progname, PQerrorMessage(conn));
        disconnect_and_exit(1);
    }

    while (1)
    {
        int         r;

        if (copybuf != NULL)
        {
            PQfreemem(copybuf);
            copybuf = NULL;
        }

        r = PQgetCopyData(conn, &copybuf, 0);

        if (r == -1)
        {
            /*
             * End of chunk
             */
            if (file)
                fclose(file);

            break;
        }
        else if (r == -2)
        {
            fprintf(stderr, _("%s: could not read COPY data: %s"),
                    progname, PQerrorMessage(conn));
            disconnect_and_exit(1);
        }

        if (file == NULL)
        {
            int         filemode;

            /*
             * No current file, so this must be the header for a new file
             */
            if (r != 512)
            {
                fprintf(stderr, _("%s: invalid tar block header size: %d\n"),
                        progname, r);
                disconnect_and_exit(1);
            }
            totaldone += 512;

            if (sscanf(copybuf + 124, "%11o", &current_len_left) != 1)
            {
                fprintf(stderr, _("%s: could not parse file size\n"),
                        progname);
                disconnect_and_exit(1);
            }

            /* Set permissions on the file */
            if (sscanf(&copybuf[100], "%07o ", &filemode) != 1)
            {
                fprintf(stderr, _("%s: could not parse file mode\n"),
                        progname);
                disconnect_and_exit(1);
            }

            /*
             * All files are padded up to 512 bytes
             */
            current_padding =
                ((current_len_left + 511) & ~511) - current_len_left;

            /*
             * First part of header is zero terminated filename
             */
            snprintf(filename, sizeof(filename), "%s/%s", current_path,
                     copybuf);
            if (filename[strlen(filename) - 1] == '/')
            {
                /*
                 * Ends in a slash means directory or symlink to directory
                 */
                if (copybuf[156] == '5')
                {
                    /*
                     * Directory
                     */
                    filename[strlen(filename) - 1] = '\0';      /* Remove trailing slash */
                    if (mkdir(filename, S_IRWXU) != 0)
                    {
                        /*
                         * When streaming WAL, pg_xlog will have been created
                         * by the wal receiver process, so just ignore failure
                         * on that.
                         */
                        if (!streamwal || strcmp(filename + strlen(filename) - 8, "/pg_xlog") != 0)
                        {
                            fprintf(stderr,
                            _("%s: could not create directory \"%s\": %s\n"),
                                    progname, filename, strerror(errno));
                            disconnect_and_exit(1);
                        }
                    }
#ifndef WIN32
                    if (chmod(filename, (mode_t) filemode))
                        fprintf(stderr,
                                _("%s: could not set permissions on directory \"%s\": %s\n"),
                                progname, filename, strerror(errno));
#endif
                }
                else if (copybuf[156] == '2')
                {
                    /*
                     * Symbolic link
                     */
                    filename[strlen(filename) - 1] = '\0';      /* Remove trailing slash */
                    if (symlink(&copybuf[157], filename) != 0)
                    {
                        fprintf(stderr,
                                _("%s: could not create symbolic link from \"%s\" to \"%s\": %s\n"),
                         progname, filename, &copybuf[157], strerror(errno));
                        disconnect_and_exit(1);
                    }
                }
                else
                {
                    fprintf(stderr,
                            _("%s: unrecognized link indicator \"%c\"\n"),
                            progname, copybuf[156]);
                    disconnect_and_exit(1);
                }
                continue;       /* directory or link handled */
            }

            /*
             * regular file
             */
            file = fopen(filename, "wb");
            if (!file)
            {
                fprintf(stderr, _("%s: could not create file \"%s\": %s\n"),
                        progname, filename, strerror(errno));
                disconnect_and_exit(1);
            }

#ifndef WIN32
            if (chmod(filename, (mode_t) filemode))
                fprintf(stderr, _("%s: could not set permissions on file \"%s\": %s\n"),
                        progname, filename, strerror(errno));
#endif

            if (current_len_left == 0)
            {
                /*
                 * Done with this file, next one will be a new tar header
                 */
                fclose(file);
                file = NULL;
                continue;
            }
        }                       /* new file */
        else
        {
            /*
             * Continuing blocks in existing file
             */
            if (current_len_left == 0 && r == current_padding)
            {
                /*
                 * Received the padding block for this file, ignore it and
                 * close the file, then move on to the next tar header.
                 */
                fclose(file);
                file = NULL;
                totaldone += r;
                continue;
            }

            if (fwrite(copybuf, r, 1, file) != 1)
            {
                fprintf(stderr, _("%s: could not write to file \"%s\": %s\n"),
                        progname, filename, strerror(errno));
                disconnect_and_exit(1);
            }
            totaldone += r;
            if (showprogress)
                progress_report(rownum, filename);

            current_len_left -= r;
            if (current_len_left == 0 && current_padding == 0)
            {
                /*
                 * Received the last block, and there is no padding to be
                 * expected. Close the file and move on to the next tar
                 * header.
                 */
                fclose(file);
                file = NULL;
                continue;
            }
        }                       /* continuing data in existing file */
    }                           /* loop over all data blocks */

    if (file != NULL)
    {
        fprintf(stderr,
                _("%s: COPY stream ended before last file was finished\n"),
                progname);
        disconnect_and_exit(1);
    }

    if (copybuf != NULL)
        PQfreemem(copybuf);

    if (basetablespace && writerecoveryconf)
        WriteRecoveryConf();
}

/*
 * Escape single quotes used in connection parameters
 */
static char *
escape_quotes(const char *src)
{
    char       *result = escape_single_quotes_ascii(src);

    if (!result)
    {
        fprintf(stderr, _("%s: out of memory\n"), progname);
        exit(1);
    }
    return result;
}

/*
 * Create a recovery.conf file in memory using a PQExpBuffer
 */
static void
GenerateRecoveryConf(PGconn *conn)
{
    PQconninfoOption *connOptions;
    PQconninfoOption *option;

    recoveryconfcontents = createPQExpBuffer();
    if (!recoveryconfcontents)
    {
        fprintf(stderr, _("%s: out of memory\n"), progname);
        disconnect_and_exit(1);
    }

    connOptions = PQconninfo(conn);
    if (connOptions == NULL)
    {
        fprintf(stderr, _("%s: out of memory\n"), progname);
        disconnect_and_exit(1);
    }

    appendPQExpBufferStr(recoveryconfcontents, "standby_mode = 'on'\n");
    appendPQExpBufferStr(recoveryconfcontents, "primary_conninfo = '");

    for (option = connOptions; option && option->keyword; option++)
    {
        char       *escaped;

        /*
         * Do not emit this setting if: - the setting is "replication",
         * "dbname" or "fallback_application_name", since these would be
         * overridden by the libpqwalreceiver module anyway. - not set or
         * empty.
         */
        if (strcmp(option->keyword, "replication") == 0 ||
            strcmp(option->keyword, "dbname") == 0 ||
            strcmp(option->keyword, "fallback_application_name") == 0 ||
            (option->val == NULL) ||
            (option->val != NULL && option->val[0] == '\0'))
            continue;

        /*
         * Write "keyword='value'" pieces, the value string is escaped if
         * necessary and doubled single quotes around the value string.
         */
        escaped = escape_quotes(option->val);

        appendPQExpBuffer(recoveryconfcontents, "%s=''%s'' ", option->keyword, escaped);

        free(escaped);
    }

    appendPQExpBufferStr(recoveryconfcontents, "'\n");
    if (PQExpBufferBroken(recoveryconfcontents))
    {
        fprintf(stderr, _("%s: out of memory\n"), progname);
        disconnect_and_exit(1);
    }

    PQconninfoFree(connOptions);
}


/*
 * Write a recovery.conf file into the directory specified in basedir,
 * with the contents already collected in memory.
 */
static void
WriteRecoveryConf(void)
{
    char        filename[MAXPGPATH];
    FILE       *cf;

    sprintf(filename, "%s/recovery.conf", basedir);

    cf = fopen(filename, "w");
    if (cf == NULL)
    {
        fprintf(stderr, _("%s: could not create file \"%s\": %s\n"), progname, filename, strerror(errno));
        disconnect_and_exit(1);
    }

    if (fwrite(recoveryconfcontents->data, recoveryconfcontents->len, 1, cf) != 1)
    {
        fprintf(stderr,
                _("%s: could not write to file \"%s\": %s\n"),
                progname, filename, strerror(errno));
        disconnect_and_exit(1);
    }

    fclose(cf);
}


static void
BaseBackup(void)
{
    PGresult   *res;
    char       *sysidentifier;
    uint32      latesttli;
    uint32      starttli;
    char        current_path[MAXPGPATH];
    char        escaped_label[MAXPGPATH];
    int         i;
    char        xlogstart[64];
    char        xlogend[64];
    int         minServerMajor,
                maxServerMajor;
    int         serverMajor;

    /*
     * Connect in replication mode to the server
     */
    conn = GetConnection();
    if (!conn)
        /* Error message already written in GetConnection() */
        exit(1);

    /*
     * Check server version. BASE_BACKUP command was introduced in 9.1, so
     * we can't work with servers older than 9.1.
     */
    minServerMajor = 901;
    maxServerMajor = PG_VERSION_NUM / 100;
    serverMajor = PQserverVersion(conn) / 100;
    if (serverMajor < minServerMajor || serverMajor > maxServerMajor)
    {
        const char *serverver = PQparameterStatus(conn, "server_version");
        fprintf(stderr, _("%s: incompatible server version %s\n"),
                progname, serverver ? serverver : "'unknown'");
        disconnect_and_exit(1);
    }

    /*
     * If WAL streaming was requested, also check that the server is new
     * enough for that.
     */
    if (streamwal && !CheckServerVersionForStreaming(conn))
    {
        /* Error message already written in CheckServerVersionForStreaming() */
        disconnect_and_exit(1);
    }

    /*
     * Build contents of recovery.conf if requested
     */
    if (writerecoveryconf)
        GenerateRecoveryConf(conn);

    /*
     * Run IDENTIFY_SYSTEM so we can get the timeline
     */
    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);
    }
    sysidentifier = pg_strdup(PQgetvalue(res, 0, 0));
    latesttli = atoi(PQgetvalue(res, 0, 1));
    PQclear(res);

    /*
     * Start the actual backup
     */
    PQescapeStringConn(conn, escaped_label, label, sizeof(escaped_label), &i);
    snprintf(current_path, sizeof(current_path),
             "BASE_BACKUP LABEL '%s' %s %s %s %s",
             escaped_label,
             showprogress ? "PROGRESS" : "",
             includewal && !streamwal ? "WAL" : "",
             fastcheckpoint ? "FAST" : "",
             includewal ? "NOWAIT" : "");

    if (PQsendQuery(conn, current_path) == 0)
    {
        fprintf(stderr, _("%s: could not send replication command \"%s\": %s"),
                progname, "BASE_BACKUP", PQerrorMessage(conn));
        disconnect_and_exit(1);
    }

    /*
     * Get the starting xlog position
     */
    res = PQgetResult(conn);
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr, _("%s: could not initiate base backup: %s"),
                progname, PQerrorMessage(conn));
        disconnect_and_exit(1);
    }
    if (PQntuples(res) != 1)
    {
        fprintf(stderr,
                _("%s: server returned unexpected response to BASE_BACKUP command; got %d rows and %d fields, expected %d rows and %d fields\n"),
                progname, PQntuples(res), PQnfields(res), 1, 2);
        disconnect_and_exit(1);
    }

    strcpy(xlogstart, PQgetvalue(res, 0, 0));
    /*
     * 9.3 and later sends the TLI of the starting point. With older servers,
     * assume it's the same as the latest timeline reported by IDENTIFY_SYSTEM.
     */
    if (PQnfields(res) >= 2)
        starttli = atoi(PQgetvalue(res, 0, 1));
    else
        starttli = latesttli;
    PQclear(res);
    MemSet(xlogend, 0, sizeof(xlogend));

    if (verbose && includewal)
        fprintf(stderr, _("transaction log start point: %s on timeline %u\n"),
                xlogstart, starttli);

    /*
     * Get the header
     */
    res = PQgetResult(conn);
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr, _("%s: could not get backup header: %s"),
                progname, PQerrorMessage(conn));
        disconnect_and_exit(1);
    }
    if (PQntuples(res) < 1)
    {
        fprintf(stderr, _("%s: no data returned from server\n"), progname);
        disconnect_and_exit(1);
    }

    /*
     * Sum up the total size, for progress reporting
     */
    totalsize = totaldone = 0;
    tablespacecount = PQntuples(res);
    for (i = 0; i < PQntuples(res); i++)
    {
        if (showprogress)
            totalsize += atol(PQgetvalue(res, i, 2));

        /*
         * Verify tablespace directories are empty. Don't bother with the
         * first once since it can be relocated, and it will be checked before
         * we do anything anyway.
         */
        if (format == 'p' && !PQgetisnull(res, i, 1))
            verify_dir_is_empty_or_create(PQgetvalue(res, i, 1));
    }

    /*
     * When writing to stdout, require a single tablespace
     */
    if (format == 't' && strcmp(basedir, "-") == 0 && PQntuples(res) > 1)
    {
        fprintf(stderr,
                _("%s: can only write single tablespace to stdout, database has %d\n"),
                progname, PQntuples(res));
        disconnect_and_exit(1);
    }

    /*
     * If we're streaming WAL, start the streaming session before we start
     * receiving the actual data chunks.
     */
    if (streamwal)
    {
        if (verbose)
            fprintf(stderr, _("%s: starting background WAL receiver\n"),
                    progname);
        StartLogStreamer(xlogstart, starttli, sysidentifier);
    }

    /*
     * Start receiving chunks
     */
    for (i = 0; i < PQntuples(res); i++)
    {
        if (format == 't')
            ReceiveTarFile(conn, res, i);
        else
            ReceiveAndUnpackTarFile(conn, res, i);
    }                           /* Loop over all tablespaces */

    if (showprogress)
    {
        progress_report(PQntuples(res), NULL);
        fprintf(stderr, "\n");  /* Need to move to next line */
    }
    PQclear(res);

    /*
     * Get the stop position
     */
    res = PQgetResult(conn);
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr,
         _("%s: could not get transaction log end position from server: %s"),
                progname, PQerrorMessage(conn));
        disconnect_and_exit(1);
    }
    if (PQntuples(res) != 1)
    {
        fprintf(stderr,
             _("%s: no transaction log end position returned from server\n"),
                progname);
        disconnect_and_exit(1);
    }
    strcpy(xlogend, PQgetvalue(res, 0, 0));
    if (verbose && includewal)
        fprintf(stderr, "transaction log end point: %s\n", xlogend);
    PQclear(res);

    res = PQgetResult(conn);
    if (PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, _("%s: final receive failed: %s"),
                progname, PQerrorMessage(conn));
        disconnect_and_exit(1);
    }

    if (bgchild > 0)
    {
#ifndef WIN32
        int         status;
        int         r;
#else
        DWORD       status;
        uint32      hi,
                    lo;
#endif

        if (verbose)
            fprintf(stderr,
                    _("%s: waiting for background process to finish streaming ...\n"), progname);

#ifndef WIN32
        if (write(bgpipe[1], xlogend, strlen(xlogend)) != strlen(xlogend))
        {
            fprintf(stderr,
                    _("%s: could not send command to background pipe: %s\n"),
                    progname, strerror(errno));
            disconnect_and_exit(1);
        }

        /* Just wait for the background process to exit */
        r = waitpid(bgchild, &status, 0);
        if (r == -1)
        {
            fprintf(stderr, _("%s: could not wait for child process: %s\n"),
                    progname, strerror(errno));
            disconnect_and_exit(1);
        }
        if (r != bgchild)
        {
            fprintf(stderr, _("%s: child %d died, expected %d\n"),
                    progname, r, (int) bgchild);
            disconnect_and_exit(1);
        }
        if (!WIFEXITED(status))
        {
            fprintf(stderr, _("%s: child process did not exit normally\n"),
                    progname);
            disconnect_and_exit(1);
        }
        if (WEXITSTATUS(status) != 0)
        {
            fprintf(stderr, _("%s: child process exited with error %d\n"),
                    progname, WEXITSTATUS(status));
            disconnect_and_exit(1);
        }
        /* Exited normally, we're happy! */
#else                           /* WIN32 */

        /*
         * On Windows, since we are in the same process, we can just store the
         * value directly in the variable, and then set the flag that says
         * it's there.
         */
        if (sscanf(xlogend, "%X/%X", &hi, &lo) != 2)
        {
            fprintf(stderr,
                  _("%s: could not parse transaction log location \"%s\"\n"),
                    progname, xlogend);
            disconnect_and_exit(1);
        }
        xlogendptr = ((uint64) hi) << 32 | lo;
        InterlockedIncrement(&has_xlogendptr);

        /* First wait for the thread to exit */
        if (WaitForSingleObjectEx((HANDLE) bgchild, INFINITE, FALSE) !=
            WAIT_OBJECT_0)
        {
            _dosmaperr(GetLastError());
            fprintf(stderr, _("%s: could not wait for child thread: %s\n"),
                    progname, strerror(errno));
            disconnect_and_exit(1);
        }
        if (GetExitCodeThread((HANDLE) bgchild, &status) == 0)
        {
            _dosmaperr(GetLastError());
            fprintf(stderr, _("%s: could not get child thread exit status: %s\n"),
                    progname, strerror(errno));
            disconnect_and_exit(1);
        }
        if (status != 0)
        {
            fprintf(stderr, _("%s: child thread exited with error %u\n"),
                    progname, (unsigned int) status);
            disconnect_and_exit(1);
        }
        /* Exited normally, we're happy */
#endif
    }

    /* Free the recovery.conf contents */
    destroyPQExpBuffer(recoveryconfcontents);

    /*
     * End of copy data. Final result is already checked inside the loop.
     */
    PQclear(res);
    PQfinish(conn);

    if (verbose)
        fprintf(stderr, "%s: base backup completed\n", progname);
}


int
main(int argc, char **argv)
{
    static struct option long_options[] = {
        {"help", no_argument, NULL, '?'},
        {"version", no_argument, NULL, 'V'},
        {"pgdata", required_argument, NULL, 'D'},
        {"format", required_argument, NULL, 'F'},
        {"checkpoint", required_argument, NULL, 'c'},
        {"write-recovery-conf", no_argument, NULL, 'R'},
        {"xlog", no_argument, NULL, 'x'},
        {"xlog-method", required_argument, NULL, 'X'},
        {"gzip", no_argument, NULL, 'z'},
        {"compress", required_argument, NULL, 'Z'},
        {"label", required_argument, NULL, 'l'},
        {"dbname", required_argument, NULL, 'd'},
        {"host", required_argument, NULL, 'h'},
        {"port", required_argument, NULL, 'p'},
        {"username", required_argument, NULL, 'U'},
        {"no-password", no_argument, NULL, 'w'},
        {"password", no_argument, NULL, 'W'},
        {"status-interval", required_argument, NULL, 's'},
        {"verbose", no_argument, NULL, 'v'},
        {"progress", no_argument, NULL, 'P'},
        {NULL, 0, NULL, 0}
    };
    int         c;

    int         option_index;

    progname = get_progname(argv[0]);
    set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_basebackup"));

    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_basebackup (PostgreSQL) " PG_VERSION);
            exit(0);
        }
    }

    while ((c = getopt_long(argc, argv, "D:F:RxX:l:zZ:d:c:h:p:U:s:wWvP",
                            long_options, &option_index)) != -1)
    {
        switch (c)
        {
            case 'D':
                basedir = pg_strdup(optarg);
                break;
            case 'F':
                if (strcmp(optarg, "p") == 0 || strcmp(optarg, "plain") == 0)
                    format = 'p';
                else if (strcmp(optarg, "t") == 0 || strcmp(optarg, "tar") == 0)
                    format = 't';
                else
                {
                    fprintf(stderr,
                            _("%s: invalid output format \"%s\", must be \"plain\" or \"tar\"\n"),
                            progname, optarg);
                    exit(1);
                }
                break;
            case 'R':
                writerecoveryconf = true;
                break;
            case 'x':
                if (includewal)
                {
                    fprintf(stderr,
                     _("%s: cannot specify both --xlog and --xlog-method\n"),
                            progname);
                    exit(1);
                }

                includewal = true;
                streamwal = false;
                break;
            case 'X':
                if (includewal)
                {
                    fprintf(stderr,
                     _("%s: cannot specify both --xlog and --xlog-method\n"),
                            progname);
                    exit(1);
                }

                includewal = true;
                if (strcmp(optarg, "f") == 0 ||
                    strcmp(optarg, "fetch") == 0)
                    streamwal = false;
                else if (strcmp(optarg, "s") == 0 ||
                         strcmp(optarg, "stream") == 0)
                    streamwal = true;
                else
                {
                    fprintf(stderr,
                            _("%s: invalid xlog-method option \"%s\", must be \"fetch\" or \"stream\"\n"),
                            progname, optarg);
                    exit(1);
                }
                break;
            case 'l':
                label = pg_strdup(optarg);
                break;
            case 'z':
#ifdef HAVE_LIBZ
                compresslevel = Z_DEFAULT_COMPRESSION;
#else
                compresslevel = 1;      /* will be rejected below */
#endif
                break;
            case 'Z':
                compresslevel = atoi(optarg);
                if (compresslevel <= 0 || compresslevel > 9)
                {
                    fprintf(stderr, _("%s: invalid compression level \"%s\"\n"),
                            progname, optarg);
                    exit(1);
                }
                break;
            case 'c':
                if (pg_strcasecmp(optarg, "fast") == 0)
                    fastcheckpoint = true;
                else if (pg_strcasecmp(optarg, "spread") == 0)
                    fastcheckpoint = false;
                else
                {
                    fprintf(stderr, _("%s: invalid checkpoint argument \"%s\", must be \"fast\" or \"spread\"\n"),
                            progname, optarg);
                    exit(1);
                }
                break;
            case 'd':
                connection_string = pg_strdup(optarg);
                break;
            case 'h':
                dbhost = pg_strdup(optarg);
                break;
            case 'p':
                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 'v':
                verbose++;
                break;
            case 'P':
                showprogress = true;
                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);
    }

    /*
     * Mutually exclusive arguments
     */
    if (format == 'p' && compresslevel != 0)
    {
        fprintf(stderr,
                _("%s: only tar mode backups can be compressed\n"),
                progname);
        fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
                progname);
        exit(1);
    }

    if (format != 'p' && streamwal)
    {
        fprintf(stderr,
                _("%s: WAL streaming can only be used in plain mode\n"),
                progname);
        fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
                progname);
        exit(1);
    }

#ifndef HAVE_LIBZ
    if (compresslevel != 0)
    {
        fprintf(stderr,
                _("%s: this build does not support compression\n"),
                progname);
        exit(1);
    }
#endif

    /*
     * Verify that the target directory exists, or create it. For plaintext
     * backups, always require the directory. For tar backups, require it
     * unless we are writing to stdout.
     */
    if (format == 'p' || strcmp(basedir, "-") != 0)
        verify_dir_is_empty_or_create(basedir);

    BaseBackup();

    return 0;
}