source: MondoRescue/trunk/mondo/mondo/common/libmondo-stream.c@ 1

/* libmondo-stream.c
   $Id: libmondo-stream.c,v 1.4 2004/06/21 20:20:36 hugo Exp $

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


07/10
- added ACL and XATTR support

04/17
- added bkpinfo->internal_tape_block_size
- fixed bug in set_tape_block_size_with_mt()

03/25
- call 'mt' when opening tape in/out, to set block size to 32K

02/06/2004
- only eject_device() at end of closein_tape() --- not closeout_tape()

10/26/2003
- call eject_device() at end of closein_tape() and closeout_tape()
 
09/25
- added docu-header to each subroutine

09/20
- working on multi-tape code
- friendlier message in insist_on_this_tape_number()
- delay is now 5s

09/10
- adding multi-tape support
- adding 'back catalog' of previous archives, so that we may resume
  from point of end-of-tape (approx.)

09/08
- cleaned up insist_on_this_tape_number() --- 10s delay for same tape now

08/27
- improved find_tape_device_and_size() --- tries /dev/osst*

05/05
- added Joshua Oreman's FreeBSD patches

04/24
- added lots of assert()'s and log_OS_error()'s

04/06/2003
- use find_home_of_exe() instead of which

12/13/2002
- cdrecord -scanbus call was missing 2> /dev/null

11/24
- disabled fatal_error("Bad marker")

10/29
- replaced convoluted grep wih wc (KP)

09/07
- removed g_end_of_tape_reached
- lots of multitape-related fixes

08/01 - 08/31
- write 16MB of zeroes to end of tape when closing(out)
- compensate for 'buffer' and its distortion of speed of writing/reading
  when writing/reading data disks at start of tape
- rewrote lots of multitape stuff
- wrote workaround to allow >2GB of archives w/buffering
- do not close/reopen tape when starting to read/write from
  new tape: no need! 'buffer' handles all that; we're writing
  to/reading from a FIFO, so no need to close/reopen when new tape
- write 8MB of zeroes at end of tape, just in case
- re-enable various calls to *_evalcall_form
- added g_end_of_tape_reached
- fixed bugs in start_to_[read|write]_[to|from]_next_tape
- added internal buffering, replacing the external 'buffer' exe
- wait 10 seconds (after user inserts new tape), to
  let tape stabilize in drive
- added insist_on_this_tape_number()
- worked on find_tape_device_and_size()
- cleaned up some log_it() calls
- added find_tape_device_and_size()
- replaced using_cdstream with backup_media_type
- replace *_from_tape with *_from_stream
- replace *_to_stream with *_to_stream

07/01 - 07/31
- leave 32MB at end of tape, to avoid overrunning
- started [07/24/2002]
*/


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

#include "my-stuff.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

/*@unused@*/
//static char cvsid[] = "$Id: libmondo-stream.c,v 1.4 2004/06/21 20:20:36 hugo Exp $";
extern bool g_sigpipe;
extern int g_tape_buffer_size_MB;

/**
 * @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 (struct s_bkpinfo *bkpinfo);





/**
 * @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 (struct s_bkpinfo *bkpinfo)
{
  return (closein_tape (bkpinfo));
}


/**
 * 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 (struct s_bkpinfo *bkpinfo)
{
    /*@ 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;

  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++)
    {
        (void) fread (blk, 1, 256*1024, g_tape_stream);
    }
  sleep(1);
  paranoid_system("sync");
  sleep(1);
  paranoid_pclose (g_tape_stream);
  log_it("closein_tape() -- leaving");
/*
  for(i=0; i < g_tapecatalog->entries; i++)
    {
      log_it("i=%d type=%s num=%d aux=%ld", i, (g_tapecatalog->el[i].type==fileset)?"fileset":"bigslice", g_tapecatalog->el[i].number, g_tapecatalog->el[i].aux);
    }
*/
  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 (struct s_bkpinfo *bkpinfo)
{
    /*@ 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);
  paranoid_system("sync");
  sleep(1);
  log_it("closeout_tape() -- entering");
    retval+=write_header_block_to_stream (0, "end-of-backup", BLK_END_OF_BACKUP);
    retval+=write_header_block_to_stream (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++)
      {
        (void) fwrite (blk, 1, 256*1024, g_tape_stream);
        if (should_we_write_to_next_tape (bkpinfo->media_size[g_current_media_number], 256*1024))
          {
            start_to_write_to_next_tape (bkpinfo);
          }
      }
/* 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[g_current_media_number], 256*1024))
          {
            start_to_write_to_next_tape (bkpinfo);
          }
      }
*/
  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);
    }
  //  if (!bkpinfo->please_dont_eject)
  //    { eject_device(bkpinfo->media_device); }
  paranoid_free(blk);
  paranoid_free(g_tapecatalog);
  return (retval);
}



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

  malloc_string(command);
  sprintf(command, "mt -f %s status", dev);
  res = run_program_and_log_output(command, 1);
  paranoid_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.
 * @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_and_size (char*dev, char*siz)
{
  char tmp[MAX_STR_LEN];
  char command[MAX_STR_LEN*2];
  char cdr_exe[MAX_STR_LEN];
//  char tape_description_[MAX_STR_LEN];
//  char tape_manufacturer_cdr[MAX_STR_LEN];
//  FILE*fin;
  int res;

  log_to_screen("I am looking for your tape streamer. Please wait.");
  dev[0] = siz[0] = '\0';
  if (find_home_of_exe("cdrecord"))
    { strcpy(cdr_exe, "cdrecord"); }
  else
    { strcpy(cdr_exe, "dvdrecord"); }
  sprintf(command, "%s -scanbus 2> /dev/null | grep -i tape | wc -l", cdr_exe);
  strcpy (tmp, call_program_and_get_last_line_of_output(command));
  if (atoi(tmp)!=1)
    {
      log_it("Either too few or too many tape streamers for me to detect...");
      strcpy(dev, VANILLA_SCSI_TAPE);
      return 1;
    }
  sprintf(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);
  strcpy (tmp, call_program_and_get_last_line_of_output(command));
  if (strlen (tmp) < 2)
    {
      log_it ("Could not find tape device");
      return 1;
    }
  sprintf(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);
  strcpy (tmp, call_program_and_get_last_line_of_output(command));
  strcpy (dev, VANILLA_SCSI_TAPE);
  dev[strlen(dev)-1] = '\0';
  strcat(dev, tmp);     // e.g. '/dev/st0' becomes '/dev/stN'
  res = 0;
  if (!mt_says_tape_exists(dev))
    {
      strcpy(dev, ALT_TAPE);
      if (!mt_says_tape_exists(dev))
    {
      log_it ("Cannot openin %s", dev);
      strcpy(dev, "/dev/st0");
      if (!mt_says_tape_exists(dev))
        {
          log_it ("Cannot openin %s", dev);
          strcpy(dev, "/dev/osst0");
          if (!mt_says_tape_exists(dev))
        { res++; }
          else
        { res=0; }
        }
    }
    }
  
  log_it("At this point, dev = %s and res = %d" , dev, res);

  strcpy(tmp, call_program_and_get_last_line_of_output("\
cdrecord -scanbus 2> /dev/null | tr -s '\t' ' ' | \
grep \"[0-9]*,[0-9]*,[0-9]*\" | grep -v \"[0-9]*) \\*\" | grep -i TAPE | \
awk '{for(i=1; i<NF; i++) { if (index($i, \"GB\")>0) { print $i;};};};'"));

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

  siz[0] = '\0';
  log_it("res=%d; dev=%s", res, dev);

  if (res) { return(res); }

  if (strlen(tmp)<2) { siz[0]='\0'; log_it("Warning - size of tape unknown"); return(0); }
  else { strcpy(siz, tmp); return(0); }
}






int read_EXAT_files_from_tape(struct s_bkpinfo *bkpinfo, long long *ptmp_size, char *tmp_fname, int *pctrl_chr, char*xattr_fname, char*acl_fname)
{
  int res=0;
  int retval=0;
  
// xattr
          res = read_header_block_from_stream(ptmp_size, tmp_fname, pctrl_chr);
          if(*pctrl_chr!=BLK_START_EXAT_FILE){wrong_marker(BLK_START_EXAT_FILE,*pctrl_chr);}
      if (!strstr(tmp_fname, "xattr")) { fatal_error("Wrong order, sunshine."); }
      read_file_from_stream_to_file(bkpinfo, xattr_fname, *ptmp_size);
      res = read_header_block_from_stream(ptmp_size, tmp_fname, pctrl_chr);
          if(*pctrl_chr!= BLK_STOP_EXAT_FILE) {wrong_marker(BLK_STOP_EXAT_FILE,*pctrl_chr);}
// acl
      res = read_header_block_from_stream(ptmp_size, tmp_fname, pctrl_chr);
      if (!strstr(tmp_fname, "acl")) { fatal_error("Wrong order, sunshine."); }
          if(*pctrl_chr!=BLK_START_EXAT_FILE){wrong_marker(BLK_START_EXAT_FILE,*pctrl_chr);}
      read_file_from_stream_to_file(bkpinfo, acl_fname, *ptmp_size);
          res = read_header_block_from_stream(ptmp_size, tmp_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, tmp_fname, pctrl_chr);
          if(*pctrl_chr!= BLK_STOP_EXTENDED_ATTRIBUTES)
        { wrong_marker(BLK_STOP_EXTENDED_ATTRIBUTES,*pctrl_chr); }
// tarball itself
          res=read_header_block_from_stream(ptmp_size, tmp_fname, pctrl_chr);
      log_msg(1, "Got xattr and acl; now looking for afioball");
      return(retval);
}


int write_EXAT_files_to_tape(struct s_bkpinfo *bkpinfo, char*xattr_fname, char*acl_fname)
{
  int res=0;
// EXATs
              write_header_block_to_stream(length_of_file(xattr_fname), xattr_fname, BLK_START_EXTENDED_ATTRIBUTES);
// xattr
              write_header_block_to_stream(length_of_file(xattr_fname), xattr_fname, BLK_START_EXAT_FILE);
          write_file_to_stream_from_file(bkpinfo, xattr_fname);  
          write_header_block_to_stream(-1, xattr_fname, BLK_STOP_EXAT_FILE);
// acl
              write_header_block_to_stream(length_of_file(acl_fname), acl_fname, BLK_START_EXAT_FILE);
          write_file_to_stream_from_file(bkpinfo, acl_fname);  
          write_header_block_to_stream(-1, acl_fname, BLK_STOP_EXAT_FILE);
              write_header_block_to_stream(length_of_file(xattr_fname), xattr_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[MAX_STR_LEN];

  log_it("Insisting on tape #%d", tapeno);
  if (g_current_media_number != tapeno)
    {
      //      log_it("g_current_media_number = %d", g_current_media_number);
      sprintf(tmp, "When the tape drive goes quiet, please insert volume %d in this series.", tapeno);
      popup_and_OK (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, final_actually_certain_writeK=0, cposK, bufsize_K;
  int last, curr, i;
  t_archtype type=other;
  char command[MAX_STR_LEN];
  char tmpdir[MAX_STR_LEN];
  char old_fname[MAX_STR_LEN];
  char *p;
  char suffix[16];

  bufsize_K = (long long)(1024LL * (1+g_tape_buffer_size_MB) );
  sprintf(tmpdir, "%s/tmpfs/backcatalog", td);
  if ((p=strrchr(latest_fname, '.'))) { strcpy(suffix, ++p); } else { suffix[0] = '\0'; }
  if (strstr(latest_fname, ".afio.") || strstr(latest_fname, ".star.")) { type = fileset; }
  else if (strstr(latest_fname, "slice")) { type = biggieslice; }
  else
    {
      log_it("fname = %s", latest_fname);
      fatal_error("Unknown type. Internal error in maintain_collection_of_recent_archives()");
    }
  mkdir(tmpdir, 0x700);
  sprintf(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); }
  last = g_tapecatalog->entries-1;
  if ( last<=0 )
    {
      iamhere("Too early to start deleting from collection.");
      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)
        {
      final_actually_certain_writeK = cposK;
      break;
    }
    }
  if ( curr<0 )
    {
      iamhere( "Not far enough into tape to start deleting old archives from collection." );
      return( 0 );
    }
//  log_it( "There are %lld KB (more than %d KB) in my backcatalog", final_alleged_writeK - final_actually_certain_writeK, bufsize_K);

  for(i=curr-1; i>=0 && curr-i<10; i--)
    {
      sprintf(old_fname, "%s/%s", tmpdir, g_tapecatalog->el[i].fname);
      unlink(old_fname);
    }
  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 (struct s_bkpinfo *bkpinfo)
{
  return (openin_tape (bkpinfo));
}

/**
 * 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(char*tapedev, long internal_tape_block_size)
{
  char *tmp;
  int res;

  if (strncmp(tapedev, "/dev/", 5))
    {
      log_msg(1, "Not using 'mt setblk'. This isn't an actual /dev entry.");
      return(0);
    }
  malloc_string( tmp );
  sprintf(tmp, "mt -f %s setblk %ld", tapedev, internal_tape_block_size);
  res = run_program_and_log_output(tmp, 3);
  paranoid_free( tmp );
  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 (struct s_bkpinfo *bkpinfo)
{
    /*@ buffer ******************************************************/
  char fname[MAX_STR_LEN];
  char *datablock;
  char tmp[MAX_STR_LEN];
  char old_cwd[MAX_STR_LEN];
  char outfname[MAX_STR_LEN];
    /*@ int ********************************************************/
  int i;
  int j;
  int res;
  long length, templong;
  size_t k;
  int retval = 0;
  int ctrl_chr;

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

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

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

  assert_string_is_neither_NULL_nor_zerolength(bkpinfo->media_device);
  if (!(g_tapecatalog = malloc(sizeof(struct s_tapecatalog)))) { fatal_error("Cannot alloc mem for tape catalog"); }
  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); }
  insist_on_this_tape_number(1);
  sprintf (outfname, "%s/tmp/all.tar.gz", bkpinfo->tmpdir);
  make_hole_for_file (outfname);

  set_tape_block_size_with_mt(bkpinfo->media_device, bkpinfo->internal_tape_block_size);

//  start_buffer_process( bkpinfo->media_device, g_tape_fifo, FALSE);
  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"); 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");
      return(-1);
    }
  if (!(datablock = (char*)malloc(256*1024))) { log_to_screen("Unable to malloc 256*1024"); exit(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);
            }
          (void) fwrite (datablock, 1, (size_t) length, fout);
      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);
  (void) getcwd (old_cwd, MAX_STR_LEN);
  chdir (bkpinfo->tmpdir);
  sprintf (tmp, "tar -zxf %s tmp/mondo-restore.cfg 2> /dev/null", outfname);
  paranoid_system(tmp);
  paranoid_system ("cp -f tmp/mondo-restore.cfg . 2> /dev/null");
  chdir (old_cwd);
  unlink (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[MAX_STR_LEN*2];

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

/*  add 'dummy' if testing */
  sprintf (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");
  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.
 * @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 (char *tapedev, long internal_tape_block_size)
{
//  char sz_call_to_buffer[MAX_STR_LEN];
  
  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 (!(g_tapecatalog = malloc(sizeof(struct s_tapecatalog)))) { fatal_error("Cannot alloc mem for tape catalog"); }
  g_tapecatalog->entries = 0;
  g_tape_posK = 0;

  set_tape_block_size_with_mt(tapedev, internal_tape_block_size);
  log_it ("Opening OUT tape");
  if (!(g_tape_stream = open_device_via_buffer(tapedev, 'w', 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 bkpinfo The backup information structure. @c bkpinfo->media_device is the only field used.
 * @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 (struct s_bkpinfo *bkpinfo, char *outfile,
                 long long size)
{

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

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

  res = read_file_from_stream_FULL (bkpinfo, 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 (struct s_bkpinfo *bkpinfo, FILE * fout,
                   long long size)
{

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

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

  res = read_file_from_stream_FULL (bkpinfo, 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 (struct s_bkpinfo *bkpinfo, char *outfname,
              FILE * foutstream, long long orig_size)
{
    /*@ buffers ******************************************************/
  char *tmp;
  char *datablock;
  char *temp_fname;
  char *temp_cksum;
  char *actual_cksum;
//  char *pA, *pB;

    /*@ 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 = 0 /*,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;

  bool had_to_resync=FALSE;

    /*@ init  ********************************************************/
  malloc_string(tmp);
  malloc_string(temp_fname);
  malloc_string(temp_cksum);
  malloc_string(actual_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 (orig_size != temp_size && orig_size != -1)
    {
      sprintf (tmp,
           "output file's size should be %ld K but is apparently %ld K",
           (long) size >> 10, (long) temp_size >> 10);
      log_to_screen (tmp);
    }
  if (ctrl_chr != BLK_START_FILE)
    {
      wrong_marker (BLK_START_FILE, ctrl_chr);
      return(1);
    }
  sprintf (tmp, "Reading file from tape; writing to '%s'; %ld KB", outfname,
       (long) size >> 10);

  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(bkpinfo);
      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");
      had_to_resync = TRUE;
          bytes_read = fread(datablock, 1, bytes_to_read, g_tape_stream);
    }

      (void) 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

#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;
  sprintf (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);
//      fatal_error("Bad marker"); // return(1);
    }
  if (strcmp (temp_cksum, actual_cksum))
    {
      sprintf (tmp, "actual cksum=%s; recorded cksum=%s", actual_cksum,
           temp_cksum);
      log_to_screen (tmp);
      sprintf (tmp, "%s (%ld K) is corrupt on tape", temp_fname,
           (long) orig_size >> 10);
      log_to_screen (tmp);
      retval++;
    }
  else
    {
      sprintf (tmp, "%s is GOOD on tape", temp_fname);
      /*      log_it(tmp); */
    }
  paranoid_free(datablock);
  paranoid_free(tmp);
  paranoid_free(temp_fname);
  paranoid_free(temp_cksum);
  paranoid_free(actual_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;

    /*@ 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*)plength_of_incoming_file,(char*)tempblock+7001,sizeof(long long)); */
/*  for(*plen=0,i=7;i>=0;i--) {*plen<<=8; *plen |= tempblock[7001+i];} */
  memcpy ((char *) plen, tempblock + 7001, sizeof (long long));
  if (strcmp (tempblock + 6000 + *pcontrol_char, "Mondolicious, baby"))
    {
      log_it ("Bad header block at %ld K", (long) g_tape_posK);
    }
  strcpy (filename, tempblock + 1000);
/*  strcpy(cksum,tempblock+5555);*/
/*  log_it( "%s  (reading) fname=%s, filesize=%ld K",
       marker_to_string (*pcontrol_char), filename,
       (long) ((*plen) >> 10));
*/
  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';
  log_msg(6, "%s (fname=%s, size=%ld K)", marker_to_string (*pcontrol_char),
       tempblock+1000, (long) (*plen) >> 10);
  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];
  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?
 */
bool
should_we_write_to_next_tape (long mediasize,
                  long long 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 (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 (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;
          // FIXME - needs error-checking and -catching
      fread(datablock,1,(size_t) TAPE_BLOCK_SIZE, g_tape_stream);
    }
      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 (struct s_bkpinfo *bkpinfo)
{
    /*@ int **********************************************************/
  int res = 0;
  char *sz_msg;
  int ctrlchr;
  long long temp_size;
  malloc_string(sz_msg);
    /*@ end vars ****************************************************/

  paranoid_pclose(g_tape_stream);
  system("sync");system("sync");system("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 (struct s_bkpinfo *bkpinfo)
{
  int res=0;
  char command[MAX_STR_LEN*2];
  paranoid_pclose(g_tape_stream);
  system("sync");system("sync");system("sync");
  log_it ("New tape requested.");
  insist_on_this_tape_number(g_current_media_number+1); // will increment g_current_media, too
  if (g_current_media_number > MAX_NOOF_MEDIA) { res++; log_to_screen("Too many tapes. Man, you need to use nfs!"); }
  if (bkpinfo->backup_media_type == cdstream)
    {
      sprintf (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");
      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 (0, "start-of-tape", BLK_START_OF_TAPE);    /* just in case */
  res+=write_header_block_to_stream (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 (struct s_bkpinfo *bkpinfo)
{
  int i, last, res=0;
  char *fname;

  log_msg(2, "I am now writing back catalog to tape");
  malloc_string(fname);
  last = g_tapecatalog->entries-1;
  for(i=0; i<=last; i++)
    {
      sprintf(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(bkpinfo, fname))
        { res++; log_msg(2, "%s failed", fname); }
      if (i!=last)
        { write_header_block_to_stream (0, "stop-backcatalog-afio-or-slice", BLK_STOP_AN_AFIO_OR_SLICE); }
        }
    }
  paranoid_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;
  char tmp[MAX_STR_LEN];

    /*@ 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))
    {
      sprintf (tmp, "Cannot find %s", fname);
      log_to_screen (tmp);
      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 (struct s_bkpinfo *bkpinfo, char *infile)
{
    /*@ buffers *****************************************************/
  char tmp[MAX_STR_LEN];
  char datablock[TAPE_BLOCK_SIZE];
  char checksum[MAX_STR_LEN];
  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;

    /*@ long long ***************************************************/
  long long 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[g_current_media_number], filesize))
    {
      start_to_write_to_next_tape (bkpinfo);
      write_backcatalog_to_tape (bkpinfo);
    }
  p = strrchr (infile, '/');
  if (!p)
    {
      p = infile;
    }
  else
    {
      p++;
    }
  sprintf (tmp, "Writing file '%s' to tape (%ld KB)", p,
       (long) filesize >> 10);
  log_it (tmp);
  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;
    }
      (void) fread (datablock, 1, (size_t) bytes_to_read, fin);
      g_tape_posK += fwrite (datablock, 1, /*bytes_to_read */ (size_t) TAPE_BLOCK_SIZE,
                 g_tape_stream) / 1024;
      if (g_sigpipe)
        {
      iamhere("Sigpipe occurred recently. I'll start a new tape.");
      fclose(fin);
      g_sigpipe = FALSE;
          start_to_write_to_next_tape (bkpinfo);
          write_backcatalog_to_tape (bkpinfo); // 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);
  sprintf (checksum, "%04x%04x", crc16, crctt);
  write_header_block_to_stream (g_current_media_number, checksum,
                  BLK_STOP_FILE);
//  log_it("File '%s' written to tape.", infile);
  return (retval);
}





/**
 * 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 (long long length_of_incoming_file, char *filename,
                int control_char)
{
    /*@ buffers *****************************************************/
  char tempblock[TAPE_BLOCK_SIZE];
  char tmp[MAX_STR_LEN];
  char *p;

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

    /*@ long long ***************************************************/
  long long 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, "Mondolicious, baby");
  tempblock[7000] = control_char;
/*  for(i=0;i<8;i++) {tempblock[7001+i]=olen&0xff; olen>>=8;} */
  memcpy (tempblock + 7001, (char *) &olen, sizeof (long long));
/*  if (length_of_incoming_file) {memcpy(tempblock+7001,(char*)&length_of_incoming_file,sizeof(long long));} */
  strcpy (tempblock + 1000, filename);
/*  strcpy(tempblock+5555,cksum); */
  g_tape_posK += fwrite (tempblock, 1, (size_t) TAPE_BLOCK_SIZE, g_tape_stream) / 1024;
  sprintf (tmp, "%s (fname=%s, size=%ld K)", marker_to_string (control_char),
       p, (long) length_of_incoming_file >> 10);
  log_msg(6, tmp);
/*  log_tape_pos(); */
  return (0);
}










/**
 * 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)
{
    /*@ buffer ******************************************************/
  char tmp[MAX_STR_LEN];


    /*@ end vars ****************************************************/
  sprintf (tmp, "Wrong marker! (Should be %s, ",
       marker_to_string (should_be));
  sprintf (tmp + strlen (tmp), "is actually %s)", marker_to_string (it_is));
  log_to_screen (tmp);
}

/* @} - end of streamGroup */