source: MondoRescue/branches/3.3/mondo/src/common/libmondo-stream.c@ 3860

/* libmondo-stream.c
   $Id: libmondo-stream.c 3860 2024-03-07 10:00:54Z bruno $

...tools for talking to tapes, Monitas streams, etc.

*/


/**
 * @file
 * Functions for writing data to/reading data from streams (tape, CD stream, etc.)
 */

#include "my-stuff.h"
#include "mr_mem.h"
#include "mr_file.h"
#include "mondostructures.h"
#include "libmondo-devices.h"
#include "lib-common-externs.h"
#include "libmondo-stream.h"
#include "libmondo-string-EXT.h"
#include "libmondo-files-EXT.h"
#include "libmondo-gui-EXT.h"
#include "libmondo-fork-EXT.h"
#include "libmondo-tools-EXT.h"
#include "libmondo-fifo-EXT.h"

#define EXTRA_TAPE_CHECKSUMS
#define STR_HEADER  "Mondolicious, baby"

/*@unused@*/
//static char cvsid[] = "$Id: libmondo-stream.c 3860 2024-03-07 10:00:54Z bruno $";
extern bool g_sigpipe;
extern int g_tape_buffer_size_MB;

extern char *g_getfacl;
extern char *g_getfattr;
extern char *MONDO_LOGFILE;

/* Reference to global bkpinfo */
extern struct s_bkpinfo *bkpinfo;

/**
 * @addtogroup globalGroup
 * @{
 */
/**
 * The file pointer for the opened tape/CD stream.
 * Opened and closed by openin_tape(), openin_cdstream(),
 * openout_tape(), openout_cdstream(), closein_tape(), closein_cdstream(),
 * closeout_tape(), and closeout_cdstream().
 */
FILE *g_tape_stream = NULL;


/**
 * The position (in kilobytes) where we are on the tape.
 */
long long g_tape_posK = 0;

/**
 * The current media number we're using. This value is 1-based.
 */
int g_current_media_number = -1;

/**
 * The tape catalog that keeps track of files written to tape.
 */
struct s_tapecatalog *g_tapecatalog;

/* @} - end of globalGroup */

int write_backcatalog_to_tape();





/**
 * @addtogroup streamGroup
 * @{
 */
/**
 * Close the global output file descriptor which Mondo has used to read
 * from the CD stream.
 * @param bkpinfo The backup information structure. Passed directly to closein_tape().
 * @return 0 for success, nonzero for failure.
 * @note This should be called by restore processes only.
 */
int closein_cdstream()
{
    return (closein_tape());
}

/**
 * Write a header block to the opened stream (CD or tape).
 * @param length_of_incoming_file The length to store in the header block.
 * Usually matters only if this is a file-related header, in which case it should
 * be the length of the file that will follow.
 * @param filename The filename to store in the header block. Usually matters
 * only if this is a file-related header, in which case this should be the name
 * if the file that will follow.
 * @param control_char The type of header block this is (start-file, end-file, start-tape, ...)
 * @return 0 for success, nonzero for failure.
 */
int write_header_block_to_stream(off_t length_of_incoming_file, const char *filename, int control_char)
{
    /*@ buffers **************************************************** */
    char tempblock[TAPE_BLOCK_SIZE];
    char *p;
    char *tmp = NULL;

    /*@ int ******************************************************** */
    int i;

    off_t olen;

    /*@ end vars *************************************************** */

    olen = length_of_incoming_file;
    p = strrchr(filename, '/'); /* Make 'em go, "Unnnh!" Oh wait, that was _Master_ P... */
    if (!p) {
        p = filename;
    } else {
        p++;
    }
    if (!g_tape_stream) {
        log_to_screen("You're not backing up to tape. Why write a tape header?");
        return (1);
    }
    for (i = 0; i < (int) TAPE_BLOCK_SIZE; i++) {
        tempblock[i] = 0;
    }
    sprintf(tempblock + 6000 + control_char, STR_HEADER);
    tempblock[7000] = control_char;
    if (length_of_incoming_file > 0) {
        memcpy(tempblock + 7001, (char *) &olen, sizeof(off_t));
    }
    strcpy(tempblock + 1000, filename);
    g_tape_posK += fwrite(tempblock, 1, (size_t) TAPE_BLOCK_SIZE, g_tape_stream) / 1024;
    tmp = marker_to_string(control_char);
    log_msg(6, "%s (fname=%s, size=%ld K)", tmp, p, (long) length_of_incoming_file >> 10);
    mr_free(tmp);
    return (0);
}


/**
 * Close the global output file descriptor which Mondo has used to read
 * from buffer or dd, which read from the tape.
 * @param bkpinfo The backup information structure. Unused.
 * @return 0 for success, nonzero for failure.
 * @note This should be called by restore processes only.
 * @note This function also works for cdstreams for now, but don't count on this behavior.
 * @bug @p bkpinfo parameter is unused.
 */
int closein_tape()
{
    /*@ int's ******************************************************* */
    int retval = 0;
    int res = 0;
    int ctrl_chr = '\0';

    /*@ buffers ***************************************************** */
    char fname[MAX_STR_LEN];

    /*@ long long's ************************************************* */
    long long size;
    char *blk;
    int i;
    int j;

    blk = (char *) malloc(256 * 1024);

    log_it("closein_tape() -- entering");
    res = read_header_block_from_stream(&size, fname, &ctrl_chr);
    retval += res;
    if (ctrl_chr != BLK_END_OF_BACKUP) {
        wrong_marker(BLK_END_OF_BACKUP, ctrl_chr);
    }
    res = read_header_block_from_stream(&size, fname, &ctrl_chr);
    retval += res;
    if (ctrl_chr != BLK_END_OF_TAPE) {
        wrong_marker(BLK_END_OF_TAPE, ctrl_chr);
    }
    for (i = 0; i < 8 && !feof(g_tape_stream); i++) {
        j = fread(blk, 1, 256 * 1024, g_tape_stream);
        if (j) {
            // FIXME
        }
    }
    sleep(1);
    sync();
    sleep(1);
    paranoid_pclose(g_tape_stream);
    log_it("closein_tape() -- leaving");
    if (!bkpinfo->please_dont_eject) {
        eject_device(bkpinfo->media_device);
    }
    paranoid_free(blk);
    paranoid_free(g_tapecatalog);
    return (retval);
}



/**
 * Close the global output file descriptor which Mondo has been using to write
 * to the tape device (via buffer or dd).
 * @param bkpinfo The backup information structure. @c bkpinfo->media_size is the only field used.
 * @return 0 for success, nonzero for failure.
 * @note This should be called by backup processes only.
 */
int closeout_tape()
{
    /*@ int's ******************************************************* */
    int retval = 0;
//  int res = 0;
//  int ctrl_chr = '\0';

    /*@ buffers ***************************************************** */
//  char fname[MAX_STR_LEN];

    /*@ long long's ************************************************* */
//  long long size;
    int i;
    char *blk;

    blk = (char *) malloc(256 * 1024);

    sleep(1);
    sync();
    sleep(1);
    log_it("closeout_tape() -- entering");
    retval +=
        write_header_block_to_stream((off_t)0, "end-of-backup",
                                     BLK_END_OF_BACKUP);
    retval += write_header_block_to_stream((off_t)0, "end-of-tape", BLK_END_OF_TAPE);   /* just in case */
/* write 1MB of crap */
    for (i = 0; i < 256 * 1024; i++) {
        blk[i] = (int) (random() & 0xFF);
    }
    for (i = 0; i < 4 * 8; i++) {
        if (fwrite(blk, 1, 256 * 1024, g_tape_stream)) {
            //FIXME
        }
        if (should_we_write_to_next_tape
            (bkpinfo->media_size, (off_t)256 * 1024)) {
            start_to_write_to_next_tape();
        }
    }
/* write 1MB of zeroes */
/*
    for (i = 0; i < 256*1024; i++)
      {
        blk[i] = 0;
      }
    for (i = 0; i < 4; i++)
      {
        fwrite (blk, 1, 256*1024, g_tape_stream);
        if (should_we_write_to_next_tape (bkpinfo->media_size, 256*1024))
          {
            start_to_write_to_next_tape ();
          }
      }
*/
    sleep(2);
    paranoid_pclose(g_tape_stream);
    log_it("closeout_tape() -- leaving");
    for (i = 0; i < g_tapecatalog->entries; i++) {
        log_it("i=%d type=%s num=%d aux=%ld posK=%lld", i,
               (g_tapecatalog->el[i].type ==
                fileset) ? "fileset" : "bigslice",
               g_tapecatalog->el[i].number, g_tapecatalog->el[i].aux,
               g_tapecatalog->el[i].tape_posK);
    }
    paranoid_free(blk);
    paranoid_free(g_tapecatalog);
    return (retval);
}



bool mt_says_tape_exists(char *dev)
{
    char *command = NULL;
    int res;

    mr_asprintf(command, "mt -f %s status", dev);
    res = run_program_and_log_output(command, 1);
    mr_free(command);

    if (res) {
        return (FALSE);
    } else {
        return (TRUE);
    }
}



/**
 * Determine the name and size of the tape device. Tries the SCSI tape for
 * this platform, then the IDE tape, then "/dev/st0", then "/dev/osst0".
 * @param dev Where to put the found tape device. Allocated dynamically by caller or reallocated here
 * @param siz Where to put the tape size (a string like "4GB")
 * @return 0 if success, nonzero if failure (in which @p dev and @p siz are undefined).
 */
int find_tape_device(char *dev) {
    char *tmp = NULL;
    char *command = NULL;
    char *cdr_exe = NULL;
    int res;

    log_to_screen("I am looking for your tape streamer. Please wait.");
    mr_free(dev);
    if (find_home_of_exe("cdrecord")) {
        mr_asprintf(cdr_exe, "cdrecord");
    } else {
        mr_asprintf(cdr_exe, "dvdrecord");
    }
    mr_asprintf(command, "%s -scanbus 2> /dev/null | grep -i tape | wc -l", cdr_exe);
    tmp = call_program_and_get_last_line_of_output(command);
    mr_free(command);

    if (atoi(tmp) != 1) {
        log_it("Either too few or too many tape streamers for me to detect...");
        mr_asprintf(dev, "%s", VANILLA_SCSI_TAPE);
        mr_free(tmp);
        mr_free(cdr_exe);
        return 1;
    }
    mr_free(tmp);

    mr_asprintf(command, "%s -scanbus 2> /dev/null | tr -s '\t' ' ' | grep \"[0-9]*,[0-9]*,[0-9]*\" | grep -v \"[0-9]*) \\*\" | grep -i TAPE | cut -d' ' -f2 | head -n1", cdr_exe);
    tmp = call_program_and_get_last_line_of_output(command);
    mr_free(command);

    if (strlen(tmp) < 2) {
        log_it("Could not find tape device");
        mr_free(cdr_exe);
        mr_free(tmp);
        return 1;
    }
    mr_asprintf(command, "%s -scanbus 2> /dev/null | tr -s '\t' ' ' | grep \"[0-9]*,[0-9]*,[0-9]*\" | grep -v \"[0-9]*) \\*\" | grep -i TAPE | cut -d' ' -f3 | cut -d')' -f1 | head -n1", cdr_exe);
    mr_free(cdr_exe);

    tmp = call_program_and_get_last_line_of_output(command);
    mr_free(command);

    mr_asprintf(dev, "%s", VANILLA_SCSI_TAPE);
    dev[strlen(dev) - 1] = '\0';
    mr_strcat(dev, tmp);            // e.g. '/dev/st0' becomes '/dev/stN'
    mr_free(tmp);

    res = 0;
    if (!mt_says_tape_exists(dev)) {
        mr_asprintf(dev, "%s", ALT_TAPE);
        if (!mt_says_tape_exists(dev)) {
            log_it("Cannot openin %s", dev);
            mr_asprintf(dev, "%s", "/dev/st0");
            if (!mt_says_tape_exists(dev)) {
                log_it("Cannot openin %s", dev);
                mr_asprintf(dev, "%s", "/dev/osst0");
                if (!mt_says_tape_exists(dev)) {
                    res++;
                } else {
                    res = 0;
                }
            }
        }
    }

    if (dev) {
        log_it("At this point, dev = %s and res = %d", dev, res);
    } else {
        log_it("At this point, dev is NULL and res = %d", res);
    }

    if (mt_says_tape_exists(dev)) {
        res = 0;
    } else {
        log_it("Turning %s", dev);
        mr_free(tmp);
        mr_asprintf(tmp, "%s", (strrchr(dev, '/') != NULL) ? strrchr(dev, '/') : dev);
        mr_asprintf(dev, "/dev/os%s", tmp);
        log_it("...into %s", dev);
        if (mt_says_tape_exists(dev)) {
            res = 0;
        } else {
            res++;
        }
    }
    log_it("res=%d; dev=%s", res, dev);
    return (res);
}


int read_EXAT_files_from_tape(long long *ptmp_size, char *tmp_fname,
                              int *pctrl_chr, char *xattr_fname,
                              char *acl_fname)
{
    int res = 0;
    char fname_buf[PATH_MAX];
    char *fname = (char *)fname_buf;        /* Should NOT be NULL */
    char *tmp = NULL;

    // xattr
    if (g_getfattr) {
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr != BLK_START_EXAT_FILE) {
            wrong_marker(BLK_START_EXAT_FILE, *pctrl_chr);
        }
        if (strstr(fname, "xattr") == NULL) {
            mr_asprintf(tmp,"Wrong order expected xattr, got %s, sunshine.", fname);
            fatal_error(tmp);
        }
        read_file_from_stream_to_file(xattr_fname, *ptmp_size);
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr != BLK_STOP_EXAT_FILE) {
            wrong_marker(BLK_STOP_EXAT_FILE, *pctrl_chr);
        }
        log_msg(1, "Got xattr");
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr != BLK_STOP_EXTENDED_ATTRIBUTES) {
            wrong_marker(BLK_STOP_EXTENDED_ATTRIBUTES, *pctrl_chr);
        }
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr == BLK_START_AN_AFIO_OR_SLICE) {
            log_msg(1, "No acl attributes found, skipping to afio files");
            return(0);
        } else {
            if (*pctrl_chr != BLK_START_EXTENDED_ATTRIBUTES) {
                wrong_marker(BLK_START_EXTENDED_ATTRIBUTES, *pctrl_chr);
            }
        }
    }
    // acl
    if (g_getfacl) {
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr != BLK_START_EXAT_FILE) {
            wrong_marker(BLK_START_EXAT_FILE, *pctrl_chr);
        }
        if (strstr(fname, "acl") == NULL) {
            mr_asprintf(tmp,"Wrong order expected acl, got %s, sunshine.", fname);
            fatal_error(tmp);
        }
        read_file_from_stream_to_file(acl_fname, *ptmp_size);
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr != BLK_STOP_EXAT_FILE) {
            wrong_marker(BLK_STOP_EXAT_FILE, *pctrl_chr);
        }
        res = read_header_block_from_stream(ptmp_size, fname, pctrl_chr);
        if (*pctrl_chr != BLK_STOP_EXTENDED_ATTRIBUTES) {
            wrong_marker(BLK_STOP_EXTENDED_ATTRIBUTES, *pctrl_chr);
        }
        log_msg(1, "Got acl");
    }
    // tarball itself
    res = read_header_block_from_stream(ptmp_size, tmp_fname, pctrl_chr);
    log_msg(1, "End of extended attributes, now looking for afioball");
    return (res);
}


int write_EXAT_files_to_tape(char *xattr_fname,
                             char *acl_fname)
{
    int res = 0;
    if (g_getfattr) {
    // xattr
        write_header_block_to_stream(length_of_file(xattr_fname), xattr_fname, BLK_START_EXTENDED_ATTRIBUTES);
        write_header_block_to_stream(length_of_file(xattr_fname), xattr_fname, BLK_START_EXAT_FILE);
        write_file_to_stream_from_file(xattr_fname);
        write_header_block_to_stream((off_t)-1, xattr_fname, BLK_STOP_EXAT_FILE);
        write_header_block_to_stream(length_of_file(xattr_fname), xattr_fname, BLK_STOP_EXTENDED_ATTRIBUTES);
    }
    if (g_getfacl) {
    // acl
        write_header_block_to_stream(length_of_file(acl_fname), acl_fname, BLK_START_EXTENDED_ATTRIBUTES);
        write_header_block_to_stream(length_of_file(acl_fname), acl_fname, BLK_START_EXAT_FILE);
        write_file_to_stream_from_file(acl_fname);
        write_header_block_to_stream((off_t)-1, acl_fname, BLK_STOP_EXAT_FILE);
        write_header_block_to_stream(length_of_file(acl_fname), acl_fname, BLK_STOP_EXTENDED_ATTRIBUTES);
    }
    return (res);
}




/**
 * Tell the user to insert tape @p tapeno and wait for it to settle (5 seconds).
 * @param tapeno The tape number to insist on.
 * @bug There is currently no way to actually verify that the user has actually
 * inserted the right tape.
 */
void insist_on_this_tape_number(int tapeno)
{
    int i;
    char *tmp = NULL;

    log_it("Insisting on tape #%d", tapeno);
    if (g_current_media_number != tapeno) {
        mr_asprintf(tmp, "When the tape drive goes quiet, please insert volume %d in this series.", tapeno);
        popup_and_OK(tmp);
        mr_free(tmp);
        open_evalcall_form("Waiting while the tape drive settles");
    } else {
        open_evalcall_form("Waiting while the tape drive rewinds");
    }

    for (i = 0; i <= 100; i += 2) {
        usleep(100000);
        update_evalcall_form(i);
    }
    close_evalcall_form();
    log_it("I assume user has inserted it. They _say_ they have...");
    g_current_media_number = tapeno;

    //  log_it("g_current_media_number = %d", g_current_media_number);
    log_it("OK, I've finished insisting. On with the revelry.");
}




/**
 * Debugging aid - log the offset we're at on the tape (reading or writing).
 */
void log_tape_pos(void)
{
    /*@ buffers ***************************************************** */


    /*@ end vars *************************************************** */

    log_it("Tape position -- %ld KB (%ld MB)", (long) g_tape_posK,
           (long) g_tape_posK >> 10);
}




/**
 * Add a file to a collection of recently archived filesets/slices.
 * The type is determined by the filename: if it contains ".afio." it is
 * assumed to be a fileset, otherwise if it contains "slice" it's a slice,
 * otherwise we generate a fatal_error().
 * @param td The current @c bkpinfo->tempdir (file will be placed in <tt>td</tt>/tmpfs/backcatalog/).
 * @param latest_fname The file to place in the collection.
 * @return 0, always.
 * @bug Return value is redundant.
 * @bug The detection won't work for uncompressed afioballs (they end in ".afio", no dot afterwards). // Not true. They end in '.' -Hugo
 */
int maintain_collection_of_recent_archives(char *td, char *latest_fname)
{
    long long final_alleged_writeK, final_projected_certain_writeK,
        cposK, bufsize_K;
    int last, curr, i;
    char *command = NULL;
    char *tmpdir = NULL;
    char *old_fname = NULL;
    char *p;
    char suffix[16];

    bufsize_K = (long long) (1024LL * (1 + g_tape_buffer_size_MB));
    if ((p = strrchr(latest_fname, '.'))) {
        strcpy(suffix, ++p);
    } else {
        suffix[0] = '\0';
    }
    mr_asprintf(tmpdir, "%s/tmpfs/backcatalog", td);
    mkdir(tmpdir, 0x700);
    mr_asprintf(command, "cp -f %s %s", latest_fname, tmpdir);
    if (run_program_and_log_output(command, 6)) {
        log_it("Warning - failed to copy %s to backcatalog at %s",
               latest_fname, tmpdir);
    }
    mr_free(command);

    last = g_tapecatalog->entries - 1;
    if (last <= 0) {
        log_it("Too early to start deleting from collection.");
        mr_free(tmpdir);
        return (0);
    }
    final_alleged_writeK = g_tapecatalog->el[last].tape_posK;
    final_projected_certain_writeK = final_alleged_writeK - bufsize_K;
    for (curr = last; curr >= 0; curr--) {
        cposK = g_tapecatalog->el[curr].tape_posK;
        if (cposK < final_projected_certain_writeK) {
            break;
        }
    }
    if (curr < 0) {
        log_it("Not far enough into tape to start deleting old archives from collection.");
        mr_free(tmpdir);
        return (0);
    }

    for (i = curr - 1; i >= 0 && curr - i < 10; i--) {
        mr_asprintf(old_fname, "%s/%s", tmpdir, g_tapecatalog->el[i].fname);
        unlink(old_fname);
        mr_free(old_fname);
    }
    mr_free(tmpdir);
    return (0);
}




/**
 * Open the CD stream for input.
 * @param bkpinfo The backup information structure. Passed to openin_tape().
 * @return 0 for success, nonzero for failure.
 * @note Equivalent to openin_tape() for now, but don't count on this behavior.
 */
int openin_cdstream()
{
    return (openin_tape());
}

/**
 * FIFO used to read/write to the tape device.
 * @bug This seems obsolete now that we call an external @c buffer program. Please look onto this.
 */
char g_tape_fifo[MAX_STR_LEN];



int set_tape_block_size_with_mt(long internal_tape_block_size)
{
    char *tmp = NULL;
    int res;

    if (bkpinfo->media_device == NULL) {
        return(1);
    }

    if (strncmp(bkpinfo->media_device, "/dev/", 5)) {
        log_msg(1, "Not using 'mt setblk'. This isn't an actual /dev entry.");
        return (0);
    }
    mr_asprintf(tmp, "mt -f %s setblk %ld", bkpinfo->media_device, internal_tape_block_size);
    res = run_program_and_log_output(tmp, 3);
    mr_free(tmp);
    return (res);
}

/**
 * Return the non-rewinding device when passed the normal one
 * @param tapedev The tape device to open for writing.
 * @note the caller needs to free the string returned
 */
char *get_non_rewind_dev(char *tapedev)
{

    char *ntapedev = NULL;
    char *p = NULL;
    char *q = NULL;
    char *r = NULL;

    ntapedev = (char *)mr_malloc(strlen(tapedev)+2*sizeof(char));
    p = strrchr(tapedev,'/');
    if (p == NULL) {
        log_it("Didn't find a '/' in %s",tapedev);
        return(NULL);
    }

    /* Copy tapedev content up to the last / */
    q = tapedev;
    r = ntapedev;
    while (q != p) {
        *r = *q;
        r++;
        q++;
    }
    /* Copy the '/' */
    *r = *q;
    r++;
    q++;
    /* Adds a 'n' - non-rewinding */
    *r = 'n';
    r++;
    /* Copy the rest of tapedev */
    while (*q != '\0') {
        *r = *q;
        r++;
        q++;
    }
    *r = '\0';
    if (mt_says_tape_exists(ntapedev)) {
        log_it("Non-rewinding tape device is %s",ntapedev);
    } else {
        log_it("Unable to find non-rewinding tape device.");
        ntapedev = NULL;
    }
    return(ntapedev);
}



/**
 * Handle OBDR if we were asked to do so
 * @param tapedev The tape device to open for reading.
 */
int skip_obdr(void)
{
    char *command = NULL;
    int res = 0;

    if (bkpinfo->media_device == NULL) {
        return(1);
    }

    log_it("Skipping OBDR headers");
    mr_asprintf(command, "mt -f %s rewind",bkpinfo->media_device);
    res = run_program_and_log_output(command, 1);
    paranoid_free(command);

    mr_asprintf(command, "mt -f %s fsf 2",bkpinfo->media_device);
    res = run_program_and_log_output(command, 1);
    paranoid_free(command);

    set_tape_block_size_with_mt(bkpinfo->internal_tape_block_size);
    return(res);
}

/**
 * Handle OBDR if we were asked to do so
 * @param tapedev The tape device to open for writing.
 * @return 0 for success, nonzero for failure.
 * @note This should be called ONLY from backup processes. It will OVERWRITE ANY
 * EXISTING DATA on the tape!
 */
int create_obdr(void)
{

    char *command = NULL;
    int res = 0;

    if (bkpinfo->media_device == NULL) {
        return(1);
    }

    log_it("Creating OBDR headers");
    /* OBDR: First block 10 kB of zero bs = 512 */
    mr_asprintf(command, "mt -f %s compression off",bkpinfo->media_device);
    res = run_program_and_log_output(command, 1);
    paranoid_free(command);

    mr_asprintf(command, "mt -f %s rewind",bkpinfo->media_device);
    res += run_program_and_log_output(command, 1);
    paranoid_free(command);

    set_tape_block_size_with_mt(512);

    mr_asprintf(command, "dd if=/dev/zero of=%s bs=512 count=20",bkpinfo->media_device);
    res += run_program_and_log_output(command, 1);
    paranoid_free(command);

    /* OBDR: then ISO boot image bs = 2048 */
    set_tape_block_size_with_mt(2048);

    mr_asprintf(command, "dd if=%s of=%s bs=2048",MINDI_CACHE"/mindi.iso",bkpinfo->media_device);
    res += run_program_and_log_output(command, 1);
    paranoid_free(command);

    set_tape_block_size_with_mt(bkpinfo->internal_tape_block_size);

    /* restore compression mode on */
    mr_asprintf(command, "mt -f %s compression on",bkpinfo->media_device);
    res = run_program_and_log_output(command, 1);
    paranoid_free(command);

    return(res);
}


/**
 * Open the tape device for input.
 * @param bkpinfo The backup information structure. Fields used:
 * - @c bkpinfo->media_device
 * - @c bkpinfo->tmpdir
 * @return 0 for success, nonzero for failure.
 * @note This will also work with a cdstream for now, but don't count on this behavior.
 */
int openin_tape()
{
    /*@ buffer ***************************************************** */
    char fname[MAX_STR_LEN];
    char *datablock;
    char *tmp = NULL;
    char *old_pwd = NULL;
    char *outfname = NULL;
    /*@ int ******************************************************* */
    int i;
    int j;
    int res = 0;
    long length, templong;
    size_t k;
    int retval = 0;
    int ctrl_chr;

    /*@ long long ************************************************* */
    long long size;

    /*@ pointers ************************************************** */
    FILE *fout;

    /*@ end vars *************************************************** */

    g_tapecatalog = mr_malloc(sizeof(struct s_tapecatalog));
    g_tapecatalog->entries = 0;
    g_tape_posK = 0;
    if (g_tape_stream) {
        log_it("FYI - I won't 'openin' the tape. It's already open.");
        return (0);
    }

    // mondoarchive should have configured everything to give the right non-rew device
    if ((bkpinfo->use_obdr) && (bkpinfo->media_device != NULL)) {
        res = skip_obdr();
        if (res != 0) {
            log_it("Not able to skip OBDR - Restore will have to be done manually");
        }
    } else {
        if (bkpinfo->media_device == NULL) {
            log_it("Not able to skip OBDR - Restore will have to be done manually");
            return (1);
        }
        set_tape_block_size_with_mt(bkpinfo->internal_tape_block_size);
    }

    insist_on_this_tape_number(1);
    mr_asprintf(outfname, "%s/tmp/all.tar.gz", bkpinfo->tmpdir);
    make_hole_for_file(outfname);

    log_it("Opening IN tape");
    if (!(g_tape_stream = open_device_via_buffer(bkpinfo->media_device, 'r', bkpinfo->internal_tape_block_size))) {
        log_OS_error(g_tape_fifo);
        log_to_screen("Cannot openin stream device");
        mr_free(outfname);
        return (1);
    }
    log_to_screen("Reading stream");
    log_it("stream device = '%s'", bkpinfo->media_device);
    /* skip data disks */
    open_evalcall_form("Skipping data disks on stream");
    log_to_screen("Skipping data disks on stream");
    if (!(fout = fopen(outfname, "w"))) {
        log_OS_error(outfname);
        log_to_screen("Cannot openout datadisk all.tar.gz file");
        mr_free(outfname);
        return (-1);
    }
    if (!(datablock = (char *) malloc(256 * 1024))) {
        log_to_screen("Unable to malloc 256*1024");
        mr_free(outfname);
        finish(1);
    }
    for (i = 0; i < 32; i++) {
        for (j = 0; j < 4; j++) {
            for (length = 0, k = 0; length < 256 * 1024; length += k) {
                k = fread(datablock + length, 1, 256 * 1024 - length,
                          g_tape_stream);
            }
            if (fwrite(datablock, 1, (size_t) length, fout)) {
                // FIXME
            }
            g_tape_posK += length / 1024;
        }
        if (i > 8)              // otherwise, 'buffer' distorts calculations
        {
            templong = ((i - 8) * 4 + j) * 100 / (128 - 8 * 4);
            update_evalcall_form((int) (templong));
        }
    }
    paranoid_fclose(fout);
    paranoid_free(datablock);

/* find initial blocks */
    res = read_header_block_from_stream(&size, fname, &ctrl_chr);
    retval += res;
    if (ctrl_chr != BLK_START_OF_TAPE) {
        wrong_marker(BLK_START_OF_TAPE, ctrl_chr);
    }
    res = read_header_block_from_stream(&size, fname, &ctrl_chr);
    retval += res;
    if (ctrl_chr != BLK_START_OF_BACKUP) {
        wrong_marker(BLK_START_OF_BACKUP, ctrl_chr);
    }
    close_evalcall_form();
    log_it("Saved all.tar.gz to '%s'", outfname);
    old_pwd = mr_getcwd();
    if (chdir(bkpinfo->tmpdir)) {
        // FIXME
    }
    mr_asprintf(tmp, "tar -zxf %s ./tmp/mondorestore.cfg 2> /dev/null", outfname);
    paranoid_system(tmp);
    mr_free(tmp);

    paranoid_system("cp -f tmp/mondorestore.cfg . 2> /dev/null");
    if (chdir(old_pwd)) {
        // FIXME
    }
    mr_free(old_pwd);
    unlink(outfname);
    mr_free(outfname);
    return (retval);
}


/**
 * Start writing to a CD stream.
 * @param cddev The CD device to openout via cdrecord.
 * @param speed The speed to write at.
 * @return 0 for success, nonzero for failure.
 * @note This should be called only from backup processes.
 */
int openout_cdstream(char *cddev, int speed)
{
    /*@ buffers ***************************************************** */
    char *command = NULL;

    /*@ end vars *************************************************** */

    if (cddev == NULL) {
        log_to_screen("Failed to openout NULL cddev");
        return (1);
    }
    /*  add 'dummy' if testing */
    mr_asprintf(command, "cdrecord -eject dev=%s speed=%d fs=24m -waiti - >> %s 2>> %s", cddev, speed, MONDO_LOGFILE, MONDO_LOGFILE);
    /*  initialise the catalog */
    g_current_media_number = 1;
    if (!(g_tapecatalog = malloc(sizeof(struct s_tapecatalog)))) {
        fatal_error("Cannot alloc mem for tape catalog");
    }
    g_tapecatalog->entries = 0;
    /* log stuff */
    log_it("Opening OUT cdstream with the command");
    log_it(command);
    /*  log_it("Let's see what happens, shall we?"); */
    g_tape_stream = popen(command, "w");
    mr_free(command);

    if (g_tape_stream) {
        return (0);
    } else {
        log_to_screen("Failed to openout to cdstream (fifo)");
        return (1);
    }
}


/**
 * Start writing to a tape device for the backup.
 * Handle OBDR if we were asked to do so
 * @param tapedev The tape device to open for writing.
 * @return 0 for success, nonzero for failure.
 * @note This should be called ONLY from backup processes. It will OVERWRITE ANY
 * EXISTING DATA on the tape!
 */
int openout_tape() {

g_current_media_number = 1;
if (g_tape_stream) {
    log_it("FYI - I won't 'openout' the tape. It's already open.");
    return (0);
}
if (bkpinfo->media_device == NULL) {
    log_it("Unable to openout NULL device");
    return(1);
}
g_tapecatalog = mr_malloc(sizeof(struct s_tapecatalog));
g_tapecatalog->entries = 0;
g_tape_posK = 0;

if (bkpinfo->use_obdr) {
    create_obdr();
} else {
    set_tape_block_size_with_mt(bkpinfo->internal_tape_block_size);
}
log_it("Opening OUT tape");
if (!(g_tape_stream = open_device_via_buffer(bkpinfo->media_device, 'w', bkpinfo->internal_tape_block_size))) {
    log_OS_error(g_tape_fifo);
    log_to_screen("Cannot openin stream device");
    return (1);
}
return (0);
}




/**
 * Copy a file from the opened stream (CD or tape) to @p outfile.
 * @param outfile The file to write to.
 * @param size The size of the file in the input stream.
 * @return 0 for success, nonzero for failure.
 */
int
read_file_from_stream_to_file(char *outfile, long long size)
{

    /*@ int ******************************************************** */
    int res;

    /*@ end vars *************************************************** */

    res = read_file_from_stream_FULL(outfile, NULL, size);

    return (res);
}



/**
 * Copy a file from the currently opened stream (CD or tape) to the stream indicated
 * by @p fout.
 * @param bkpinfo The backup information structure. @c bkpinfo->media_size is the only field used.
 * @param fout The stream to write the file to.
 * @param size The size of the file in bytes.
 * @return 0 for success, nonzero for failure.
 */
int
read_file_from_stream_to_stream(FILE * fout, long long size)
{

    /*@ int ******************************************************** */
    int res;

    /*@ end vars *************************************************** */

    res = read_file_from_stream_FULL(NULL, fout, size);
/*  fflush(g_tape_stream);
  fflush(fout);*/
    return (res);
}



/**
 * Copy a file from the currently opened stream (CD or tape) to either a
 * @c FILE pointer indicating a currently-opened file, or a filename indicating
 * a new file to create. This is the backbone function that read_file_from_stream_to_file()
 * and read_file_from_stream_to_stream() are wrappers for.
 * @param bkpinfo The backup information structure. @c bkpinfo->media_size is the only field used.
 * @param outfname If non-NULL, write to this file.
 * @param foutstream If non-NULL, write to this stream.
 * @param orig_size The original length of the file in bytes.
 * @return 0 for success, nonzero for failure.
 * @note Only @b one of @p outfname or @p foutstream may be non-NULL.
 */
int
read_file_from_stream_FULL(char *outfname, FILE * foutstream, long long orig_size)
{
    /*@ buffers ***************************************************** */
    char *datablock;
    char *temp_fname;
    char *temp_cksum;
    char *actual_cksum = NULL;

    /*@ int ********************************************************* */
    int retval = 0;
#ifdef EXTRA_TAPE_CHECKSUMS
    int i, ch;
#endif
    int noof_blocks;
    int ctrl_chr;
    int res;
    /*@ pointers **************************************************** */
    FILE *fout;

    /*@ long    ***************************************************** */
    long bytes_to_write = 0L /*,i */ ;
//  long bytes_successfully_read_in_this_time = 0;

    /*@ long long *************************************************** */
    long long temp_size, size;
    long bytes_read, bytes_to_read;
    long long total_read_from_tape_for_this_file = 0;
    long long where_I_was_before_tape_change = 0;
    /*@ unsigned int ************************************************ */
    /*  unsigned int ch; */
    unsigned int crc16;
    unsigned int crctt;

    /*@ init  ******************************************************* */
    malloc_string(temp_fname);
    malloc_string(temp_cksum);
    datablock = malloc(TAPE_BLOCK_SIZE);
    crc16 = 0;
    crctt = 0;
    size = orig_size;

    /*@ end vars *************************************************** */

    res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
    if (res) {
        // FIXME
    }
    if (orig_size != temp_size && orig_size != -1) {
        log_to_screen("output file's size should be %ld K but is apparently %ld K", (long) size >> 10, (long) temp_size >> 10);
    }
    if (ctrl_chr != BLK_START_FILE) {
        wrong_marker(BLK_START_FILE, ctrl_chr);
        return (1);
    }

    if (foutstream) {
        fout = foutstream;
    } else {
        fout = fopen(outfname, "w");
    }
    if (!fout) {
        log_OS_error(outfname);
        log_to_screen("Cannot openout file");
        return (1);
    }
    total_read_from_tape_for_this_file = 0;
    for (noof_blocks = 0; size > 0;
         noof_blocks++, size -=
         bytes_to_write, total_read_from_tape_for_this_file +=
         bytes_read) {
        bytes_to_write =
            (size < TAPE_BLOCK_SIZE) ? (long) size : TAPE_BLOCK_SIZE;
        bytes_to_read = TAPE_BLOCK_SIZE;
        bytes_read = fread(datablock, 1, bytes_to_read, g_tape_stream);
        while (bytes_read < bytes_to_read) {    // next tape!
//    crctt=crc16=0;
            where_I_was_before_tape_change = size;
            log_msg(4, "where_I_was_... = %lld",
                    where_I_was_before_tape_change);
            start_to_read_from_next_tape();
            log_msg(4, "Started reading from next tape.");
            skip_incoming_files_until_we_find_this_one(temp_fname);
            log_msg(4, "Skipped irrelevant files OK.");
            for (size = orig_size; size > where_I_was_before_tape_change;
                 size -= bytes_to_write) {
                bytes_read = fread(datablock, 1, bytes_to_read, g_tape_stream);
            }
            log_msg(4, "'size' is now %lld (should be %lld)", size,
                    where_I_was_before_tape_change);
            log_to_screen("Successfully re-sync'd tape");
            bytes_read = fread(datablock, 1, bytes_to_read, g_tape_stream);
        }

        if (fwrite(datablock, 1, (size_t) bytes_to_write, fout)) {  // for blocking reasons, bytes_successfully_read_in isn't necessarily the same as bytes_to_write
            // FIXME
        }

#ifdef EXTRA_TAPE_CHECKSUMS
        for (i = 0; i < (int) bytes_to_write; i++) {
            ch = datablock[i];
            crc16 = updcrcr(crc16, (unsigned) ch);
            crctt = updcrc(crctt, (unsigned) ch);
        }
#endif
    }
    log_msg(6, "Total read from tape for this file = %lld",
            total_read_from_tape_for_this_file);
    log_msg(6, ".......................... Should be %lld", orig_size);
    g_tape_posK += total_read_from_tape_for_this_file / 1024;
    mr_asprintf(actual_cksum, "%04x%04x", crc16, crctt);
    if (foutstream) {           /*log_it("Finished writing to foutstream"); */
    } else {
        paranoid_fclose(fout);
    }
    res = read_header_block_from_stream(&temp_size, temp_cksum, &ctrl_chr);
    if (ctrl_chr != BLK_STOP_FILE) {
        wrong_marker(BLK_STOP_FILE, ctrl_chr);
    }
    if (strcmp(temp_cksum, actual_cksum)) {
        log_to_screen("actual cksum=%s; recorded cksum=%s", actual_cksum, temp_cksum);
        log_to_screen("%s (%ld K) is corrupt on tape", temp_fname, (long) orig_size >> 10);
        retval++;
    }
    mr_free(actual_cksum);

    paranoid_free(datablock);
    paranoid_free(temp_fname);
    paranoid_free(temp_cksum);
    return (retval);
}



/**
 * Read a header block from the currently opened stream (CD or tape).
 * This block indicates the length of the following file (if it's file-related)
 * the filename (if it's file-related), and the block type.
 * @param plen Where to put the length of the file. Valid only for file-related header blocks.
 * @param filename Where to put the name of the file. Valid only for file-related header blocks.
 * @param pcontrol_char Where to put the type of block (e.g. start-file, end-file, start-tape, ...)
 * @return 0 for success, nonzero for failure.
 * @note If you read a marker (@p pcontrol_char) you're not expecting, you can call wrong_marker().
 */
int
read_header_block_from_stream(long long *plen, char *filename,
                              int *pcontrol_char)
{

    /*@ buffers ***************************************************** */
    char *tempblock;
    char *tmp = NULL;

    /*@ int ********************************************************* */
    int i, retval;

    /*@ end vars *************************************************** */

    tempblock = (char *) malloc((size_t) TAPE_BLOCK_SIZE);

    for (i = 0; i < (int) TAPE_BLOCK_SIZE; i++) {
        tempblock[i] = 0;
    }
    while (!(*pcontrol_char = tempblock[7000])) {
        g_tape_posK += fread(tempblock, 1, (size_t) TAPE_BLOCK_SIZE, g_tape_stream) / 1024;
    }
    memcpy((char *) plen, tempblock + 7001, sizeof(long long));
    if (strcmp(tempblock + 6000 + *pcontrol_char, STR_HEADER)) {
        log_it("Bad header block at %ld K", (long) g_tape_posK);
    }
    strcpy(filename, tempblock + 1000);
    if (*pcontrol_char == BLK_ABORTED_BACKUP) {
        log_to_screen("I can't verify an aborted backup.");
        retval = 1;
    } else {
        retval = 0;
    }
    for (i = 1000; i < 1020; i++) {
        if (tempblock[i] < 32 || tempblock[i] > 126) {
            tempblock[i] = ' ';
        }
    }
    tempblock[i] = '\0';
    tmp = marker_to_string(*pcontrol_char);
    log_msg(6, "%s (fname=%s, size=%ld K)", tmp, tempblock + 1000, (long) (*plen) >> 10);
    mr_free(tmp);
    paranoid_free(tempblock);
    return (retval);
}



/**
 * Add specified file/slice to the internal catalog of all archives written.
 * This lets us restart on a new CD/tape/whatever if it runs out of room. We just
 * write the last [buffer size] MB from the catalog to the new tape, so we know
 * we have @e all archives on some CD/tape/whatever.
 * @param type The type of file we're cataloging (afioball, slice, something else)
 * @param number The fileset number or biggiefile number.
 * @param aux The slice number if it's a biggiefile, or any other additional info.
 * @param fn The original full pathname of the file we're recording.
 * @return The index of the record we just added.
 */
int register_in_tape_catalog(t_archtype type, int number, long aux,
                             char *fn)
{
    int last;
    char fname[MAX_TAPECAT_FNAME_LEN+1];
    char *p;

    p = strrchr(fn, '/');
    if (p) {
        p++;
    } else {
        p = fn;
    }
    strncpy(fname, p, MAX_TAPECAT_FNAME_LEN);
    fname[MAX_TAPECAT_FNAME_LEN] = '\0';
    last = g_tapecatalog->entries;
    if (last >= MAX_TAPECATALOG_ENTRIES) {
        log_it
            ("Warning - can't log #%d in tape catalog - too many entries already",
             number);
        return (-1);
    }
    g_tapecatalog->el[last].type = type;
    g_tapecatalog->el[last].number = number;
    g_tapecatalog->el[last].aux = aux;
    g_tapecatalog->el[last].tape_posK = g_tape_posK;
    strcpy(g_tapecatalog->el[last].fname, fname);
    g_tapecatalog->entries++;
    return (last);              // returns the index of the record we've jsut added
}




/**
 * Decide whether we should start a new tape. This is TRUE if we've run out of tape
 * (got SIGPIPE) or look like we will.
 * @param mediasize The size of the tape in megabytes.
 * @param length_of_incoming_file The length of the file we're about to write, in bytes.
 * @bug This seems like it'll only work for media_size != autodetect, but Mondo only allows
 * autodetecting the size. Huh?
 */

/* TODO: Should be reviewed for mediasize being a off_t ??? */
bool
should_we_write_to_next_tape(long mediasize,
                             off_t length_of_incoming_file)
{
    /*@ bool's ***************************************************** */
    bool we_need_a_new_tape = FALSE;

    /*@ end vars *************************************************** */

    if (mediasize == 0) {
        return (FALSE);
    }
    if (mediasize > 0 && (g_tape_posK >> 10 >= mediasize)) {
        log_it("mediasize = %ld", mediasize);
        we_need_a_new_tape = TRUE;
        log_to_screen("Should have started a new tape/CD already");
    }
    if ((g_tape_posK + length_of_incoming_file / 1024) >> 10 >=
        mediasize - (SLICE_SIZE * 4 / 1024)) {
        log_it("g_tape_posK = %ld\nmediasize = %ld\n", g_tape_posK,
               mediasize);
        we_need_a_new_tape = TRUE;
    }
    return (we_need_a_new_tape);
}


/**
 * Seek through the stream until we find a header block where the NAME field matches
 * @p the_file_I_was_reading. This is useful if you've just started reading from
 * a new tape and want to find the file you were reading when the tape ended.
 * @param the_file_I_was_reading File name to look for.
 * @return 0 for success, nonzero for failure.
 */
int skip_incoming_files_until_we_find_this_one(char
                                               *the_file_I_was_reading)
{
    char *pA;
    char *pB;
    int res;
    int ctrl_chr;
    char *temp_fname;
    char *datablock;
    long long temp_size, size;
    long bytes_to_write;

    datablock = malloc(TAPE_BLOCK_SIZE);
    malloc_string(temp_fname);
    pB = strrchr(the_file_I_was_reading, '/');
    if (pB) {
        pB++;
    } else {
        pB = the_file_I_was_reading;
    }
    log_msg(1, "skip_incoming_..(%s)", pB);
    log_msg(2, "Looking for initial START_AN_AFIO_OR_SLICE");
    ctrl_chr = -1;
    while (ctrl_chr != BLK_START_AN_AFIO_OR_SLICE) {
        res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
        if (res) {
            // FIXME
        }
        if (ctrl_chr == BLK_START_AN_AFIO_OR_SLICE) {
            break;
        }
        log_msg(1, "%lld %s %c", temp_size, temp_fname, ctrl_chr);
        wrong_marker(BLK_START_AN_AFIO_OR_SLICE, ctrl_chr);
        log_msg(3, "Still trying to re-sync w/ tape");
    }
    while (ctrl_chr != BLK_START_FILE) {
        res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
        if (res) {
            //FIXME
        }
        if (ctrl_chr == BLK_START_FILE) {
            break;
        }
        log_msg(1, "%lld %s %c", temp_size, temp_fname, ctrl_chr);
        wrong_marker(BLK_START_FILE, ctrl_chr);
        log_msg(3, "Still trying to re-sync w/ tape");
    }
    pA = strrchr(temp_fname, '/');
    if (pA) {
        pA++;
    } else {
        pA = temp_fname;
    }
    pB = strrchr(the_file_I_was_reading, '/');
    if (pB) {
        pB++;
    } else {
        pB = the_file_I_was_reading;
    }
    while (strcmp(pA, pB)) {
        log_msg(6, "Skipping %s (it's not %s)", temp_fname, the_file_I_was_reading);
        for (size = temp_size; size > 0; size -= bytes_to_write) {
            bytes_to_write =
                (size < TAPE_BLOCK_SIZE) ? (long) size : TAPE_BLOCK_SIZE;
            if (fread(datablock, 1, (size_t) TAPE_BLOCK_SIZE, g_tape_stream)) {
                // FIXME - needs error-checking and -catching
            }
        }
        res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
        if (ctrl_chr != BLK_STOP_FILE) {
            wrong_marker(BLK_STOP_FILE, ctrl_chr);
        }
        res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
        if (ctrl_chr != BLK_STOP_AN_AFIO_OR_SLICE) {
            wrong_marker(BLK_STOP_AN_AFIO_OR_SLICE, ctrl_chr);
        }
        res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
        if (ctrl_chr != BLK_START_AN_AFIO_OR_SLICE) {
            wrong_marker(BLK_START_AN_AFIO_OR_SLICE, ctrl_chr);
        }
        res = read_header_block_from_stream(&temp_size, temp_fname, &ctrl_chr);
        if (ctrl_chr != BLK_START_FILE) {
            wrong_marker(BLK_START_FILE, ctrl_chr);
        }
        pA = strrchr(temp_fname, '/');
        if (pA) {
            pA++;
        } else {
            pA = temp_fname;
        }
        pB = strrchr(the_file_I_was_reading, '/');
        if (pB) {
            pB++;
        } else {
            pB = the_file_I_was_reading;
        }
    }
    log_msg(2, "Reading %s (it matches %s)", temp_fname, the_file_I_was_reading);
    paranoid_free(temp_fname);
    paranoid_free(datablock);
    return (0);
}


/**
 * Start to read from the next tape. Assumes the user has already inserted it.
 * @param bkpinfo The backup information structure. @c bkpinfo->media_device is the only field used.
 * @return 0 for success, nonzero for failure.
 */
int start_to_read_from_next_tape()
{
    /*@ int ********************************************************* */
    int res = 0;
    char *sz_msg;
    int ctrlchr;
    long long temp_size;
    malloc_string(sz_msg);
    /*@ end vars *************************************************** */

    if (bkpinfo->media_device == NULL) {
        log_it("Unable to open in from NULL device");
        return (1);
    }

    paranoid_pclose(g_tape_stream);
    sync();
    sync();
    sync();
    log_it("Next tape requested.");
    insist_on_this_tape_number(g_current_media_number + 1); // will increment it, too
    log_it("Opening IN the next tape");
    if (!(g_tape_stream = open_device_via_buffer(bkpinfo->media_device, 'r', bkpinfo->internal_tape_block_size))) {
        log_OS_error(g_tape_fifo);
        log_to_screen("Cannot openin stream device");
        return (1);
    }
    g_tape_posK = 0;
    g_sigpipe = FALSE;
    res += read_header_block_from_stream(&temp_size, sz_msg, &ctrlchr); /* just in case */
    if (ctrlchr != BLK_START_OF_TAPE) {
        wrong_marker(BLK_START_OF_TAPE, ctrlchr);
    }
    res += read_header_block_from_stream(&temp_size, sz_msg, &ctrlchr); /* just in case */
    if (ctrlchr != BLK_START_OF_BACKUP) {
        wrong_marker(BLK_START_OF_BACKUP, ctrlchr);
    } else {
        log_msg(3, "Next tape opened OK. Whoopee!");
    }
    paranoid_free(sz_msg);
    return (res);
}



/**
 * Start to write to the next tape. Assume the user has already inserted it.
 * @param bkpinfo The backup information structure. @c bkpinfo->media_device is the only field used.
 * @return 0 for success, nonzero for failure.
 */
int start_to_write_to_next_tape()
{
    int res = 0;
    char *command = NULL;

    if (bkpinfo->media_device == NULL) {
        log_it("Unable to open out from NULL device");
        return (1);
    }

    paranoid_pclose(g_tape_stream);
    sync();
    sync();
    sync();
    log_it("New tape requested.");
    insist_on_this_tape_number(g_current_media_number + 1); // will increment g_current_media, too
    if (bkpinfo->backup_media_type == cdstream) {
        mr_asprintf(command, "cdrecord -eject dev=%s speed=%d fs=24m -waiti - >> %s 2>> %s", bkpinfo->media_device, bkpinfo->cdrw_speed, MONDO_LOGFILE, MONDO_LOGFILE);
        log_it("Opening OUT to next CD with the command");
        log_it(command);
        log_it("Let's see what happens, shall we?");
        g_tape_stream = popen(command, "w");
        mr_free(command);

        if (!g_tape_stream) {
            log_to_screen("Failed to openout to cdstream (fifo)");
            return (1);
        }
    } else {
        log_it("Opening OUT to next tape");
        if (!(g_tape_stream = open_device_via_buffer(bkpinfo->media_device, 'w', bkpinfo->internal_tape_block_size))) {
            log_OS_error(g_tape_fifo);
            log_to_screen("Cannot openin stream device");
            return (1);
        }
    }
    g_tape_posK = 0;
    g_sigpipe = FALSE;
    res += write_header_block_to_stream((off_t)0, "start-of-tape", BLK_START_OF_TAPE);  /* just in case */
    res += write_header_block_to_stream((off_t)0, "start-of-backup", BLK_START_OF_BACKUP);  /* just in case */
    return (res);
}




/**
 * Write a bufferfull of the most recent archives to the tape. The
 * rationale behind this is a bit complex. If the previous tape ended
 * suddenly (EOF or otherwise) some archives were probably left in the
 * buffer. That means that Mondo thinks they have been written, but
 * the external binary @c buffer has not actually written them. So to
 * be safe, we start the new tape by writing the last bufferfull from
 * the old one. This insures that all archives will be on at least
 * one tape. Sounds inelegant, but it works.
 * @param bkpinfo The backup information structure. @c bkpinfo->tmpdir is the only field used.
 * @return 0 for success, nonzero for failure.
 */
int write_backcatalog_to_tape()
{
    int i, last, res = 0;
    char *fname = NULL;

    log_msg(2, "I am now writing back catalog to tape");
    last = g_tapecatalog->entries - 1;
    for (i = 0; i <= last; i++) {
        mr_asprintf(fname, "%s/tmpfs/backcatalog/%s", bkpinfo->tmpdir, g_tapecatalog->el[i].fname);
        if (!does_file_exist(fname)) {
            log_msg(6, "Can't write %s - it doesn't exist.", fname);
        } else {
            write_header_block_to_stream(length_of_file(fname), "start-backcatalog-afio-or-slice", BLK_START_AN_AFIO_OR_SLICE);
            log_msg(2, "Writing %s", fname);
            if (write_file_to_stream_from_file(fname)) {
                res++;
                log_msg(2, "%s failed", fname);
            }
            if (i != last) {
                write_header_block_to_stream((off_t)0, "stop-backcatalog-afio-or-slice", BLK_STOP_AN_AFIO_OR_SLICE);
            }
        }
        mr_free(fname);
    }
    log_msg(2, "Finished writing back catalog to tape");
    return (res);
}



/**
 * Write all.tar.gz (produced by Mindi) to the first 32M of the first tape.
 * @param fname The path to all.tar.gz.
 * @return 0 for success, nonzero for failure.
 */
int write_data_disks_to_stream(char *fname)
{
    /*@ pointers *************************************************** */
    FILE *fin;

    /*@ long ******************************************************* */
    long m = -1;
    long templong;

    /*@ int ******************************************************** */
    int i, j;

    /*@ buffers **************************************************** */
    char tempblock[256 * 1024];

    /*@ end vars *************************************************** */

    open_evalcall_form("Writing data disks to tape");
    log_to_screen("Writing data disks to tape");
    log_it("Data disks = %s", fname);
    if (!does_file_exist(fname)) {
        log_to_screen("Cannot find %s", fname);
        return (1);
    }
    if (!(fin = fopen(fname, "r"))) {
        log_OS_error(fname);
        fatal_error("Cannot openin the data disk");
    }
    for (i = 0; i < 32; i++) {  /* 32MB */
        for (j = 0; j < 4; j++) {   /* 256K x 4 = 1MB (1024K) */
            if (!feof(fin)) {
                m = (long) fread(tempblock, 1, 256 * 1024, fin);
            } else {
                m = 0;
            }
            for (; m < 256 * 1024; m++) {
                tempblock[m] = '\0';
            }
            g_tape_posK +=
                fwrite(tempblock, 1, 256 * 1024, g_tape_stream) / 1024;
        }
        if (i > g_tape_buffer_size_MB)  // otherwise, 'buffer' distorts calculations
        {
            templong = ((i - 8) * 4 + j) * 100 / (128 - 8 * 4);
            update_evalcall_form((int) (templong));
        }
    }
    paranoid_fclose(fin);
    close_evalcall_form();
    return (0);
}




/**
 * Copy @p infile to the opened stream (CD or tape).
 * @param bkpinfo The backup information structure. @c bkpinfo->media_size is the only field used.
 * @param infile The file to write to the stream.
 * @return 0 for success, nonzero for failure.
 */
int write_file_to_stream_from_file(char *infile)
{
    /*@ buffers **************************************************** */
    char datablock[TAPE_BLOCK_SIZE];
    char *checksum = NULL;
    char *infile_basename;

    /*@ int ******************************************************** */
    int retval = 0;
    int noof_blocks;

    /*  unsigned int ch; */
    unsigned int crc16;
    unsigned int crctt;

    /*@ pointers *************************************************** */
    FILE *fin;
    char *p;

    /*@ long ******************************************************* */
    long bytes_to_read = 0;
    long i;

    off_t filesize;

#ifdef EXTRA_TAPE_CHECKSUMS
    int ch;
#endif

    /*@ initialize ************************************************ */
    crc16 = 0;
    crctt = 0;



    /*@ end vars *************************************************** */

    infile_basename = strrchr(infile, '/');
    if (infile_basename) {
        infile_basename++;
    } else {
        infile_basename = infile;
    }
    filesize = length_of_file(infile);
    if (should_we_write_to_next_tape(bkpinfo->media_size, filesize)) {
        start_to_write_to_next_tape();
        write_backcatalog_to_tape();
    }
    p = strrchr(infile, '/');
    if (!p) {
        p = infile;
    } else {
        p++;
    }
    log_it("Writing file '%s' to tape (%ld KB)", p, (long) filesize >> 10);
    write_header_block_to_stream(filesize, infile_basename, BLK_START_FILE);
//go_here_to_restart_saving_of_file:
    if (!(fin = fopen(infile, "r"))) {
        log_OS_error(infile);
        return (1);
    }
    for (noof_blocks = 0; filesize > 0;
         noof_blocks++, filesize -= bytes_to_read) {
        if (filesize < TAPE_BLOCK_SIZE) {
            bytes_to_read = (long) filesize;
            for (i = 0; i < TAPE_BLOCK_SIZE; i++) {
                datablock[i] = '\0';
            }
        } else {
            bytes_to_read = TAPE_BLOCK_SIZE;
        }
        if (fread(datablock, 1, (size_t) bytes_to_read, fin)) {
            // FIXME
        }
        g_tape_posK +=
            fwrite(datablock, 1, /*bytes_to_read */ 
                   (size_t) TAPE_BLOCK_SIZE,
                   g_tape_stream) / 1024;
        if (g_sigpipe) {
            log_it("Sigpipe occurred recently. I'll start a new tape.");
            fclose(fin);
            g_sigpipe = FALSE;
            start_to_write_to_next_tape();
            write_backcatalog_to_tape();    // kinda-sorta recursive :)
            return (0);
        }
#ifdef EXTRA_TAPE_CHECKSUMS
        for (i = 0; i < bytes_to_read; i++) {
            ch = datablock[i];
            crc16 = updcrcr(crc16, (unsigned) ch);
            crctt = updcrc(crctt, (unsigned) ch);
        }
#endif
    }
    paranoid_fclose(fin);
    mr_asprintf(checksum, "%04x%04x", crc16, crctt);
    /* TODO: what does it do ??? */
    write_header_block_to_stream((off_t)g_current_media_number, checksum, BLK_STOP_FILE);
    mr_free(checksum);

//  log_it("File '%s' written to tape.", infile);
    return (retval);
}












/**
 * Log (to screen) an erroneous marker, along with what it should have been.
 * @param should_be What we were expecting.
 * @param it_is What we got.
 */
void wrong_marker(int should_be, int it_is)
{
    char *tmp1 = NULL;
    char *tmp2 = NULL;
    tmp1 =  marker_to_string(should_be);
    tmp2 =  marker_to_string(it_is);
    log_to_screen("Wrong marker! (Should be %s, is actually %s)", tmp1, tmp2);
    mr_free(tmp1);
    mr_free(tmp2);
}

/* @} - end of streamGroup */