tar/src/update.c

/* Update a tar archive.
   Copyright (C) 1988, 1992 Free Software Foundation

This file is part of GNU Tar.

GNU Tar is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Tar is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Tar; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* JF implement the 'r' 'u' and 'A' options for tar. */
/* The 'A' option is my own invention:  It means that the file-names are
   tar files, and they should simply be appended to the end of the archive.
   No attempt is made to block the reads from the args; if they're on raw
   tape or something like that, it'll probably lose. . . */

#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#ifndef STDC_HEADERS
extern int errno;
#endif

#ifdef HAVE_SYS_MTIO_H
#include <sys/ioctl.h>
#include <sys/mtio.h>
#endif

#ifdef BSD42
#include <sys/file.h>
#else
#ifndef V7
#include <fcntl.h>
#endif
#endif

#ifndef	__MSDOS__
#include <pwd.h>
#include <grp.h>
#endif

#define STDIN 0
#define STDOUT 1

#include "tar.h"
#include "port.h"
#include "rmt.h"

int time_to_start_writing = 0;	/* We've hit the end of the old stuff,
				   and its time to start writing new stuff
				   to the tape.  This involves seeking
				   back one block and re-writing the current
				   block (which has been changed). */

char *output_start;		/* Pointer to where we started to write in
				   the first block we write out.  This is used
				   if we can't backspace the output and have
				   to null out the first part of the block */

extern void skip_file ();
extern void skip_extended_headers ();

extern union record *head;
extern struct stat hstat;

void append_file ();
void close_archive ();
int confirm ();
void decode_header ();
void fl_read ();
void fl_write ();
void flush_archive ();
int move_arch ();
struct name *name_scan ();
char *name_from_list ();
void name_expand ();
void name_gather ();
void names_notfound ();
void open_archive ();
int read_header ();
void reset_eof ();
void write_block ();
void write_eot ();

/* Implement the 'r' (add files to end of archive), and 'u' (add files to
   end of archive if they arent there, or are more up to date than the
   version in the archive.) commands.*/
void
update_archive ()
{
  int found_end = 0;
  int status = 3;
  int prev_status;
  char *p;
  struct name *name;
  extern void dump_file ();

  name_gather ();
  if (cmd_mode == CMD_UPDATE)
    name_expand ();
  open_archive (2);		/* Open for updating */

  do
    {
      prev_status = status;
      status = read_header ();
      switch (status)
	{
	case EOF:
	  found_end = 1;
	  break;

	case 0:		/* A bad record */
	  userec (head);
	  switch (prev_status)
	    {
	    case 3:
	      msg ("This doesn't look like a tar archive.");
	      /* FALL THROUGH */
	    case 2:
	    case 1:
	      msg ("Skipping to next header");
	    case 0:
	      break;
	    }
	  break;

	  /* A good record */
	case 1:
	  /* printf("File %s\n",head->header.name); */
	  /* head->header.name[NAMSIZ-1]='\0'; */
	  if (cmd_mode == CMD_UPDATE && (name = name_scan (current_file_name)))
	    {

	      /* struct stat hstat; */
	      struct stat nstat;
	      int head_standard;

	      decode_header (head, &hstat, &head_standard, 0);
	      if (stat (current_file_name, &nstat) < 0)
		{
		  msg_perror ("can't stat %s:", current_file_name);
		}
	      else
		{
		  if (hstat.st_mtime >= nstat.st_mtime)
		    name->found++;
		}
	    }
	  userec (head);
	  if (head->header.isextended)
	    skip_extended_headers ();
	  skip_file ((long) hstat.st_size);
	  break;

	case 2:
	  ar_record = head;
	  found_end = 1;
	  break;
	}
    }
  while (!found_end);

  reset_eof ();
  time_to_start_writing = 1;
  output_start = ar_record->charptr;

  while (p = name_from_list ())
    {
      if (f_confirm && !confirm ("add", p))
	continue;
      if (cmd_mode == CMD_CAT)
	append_file (p);
      else
	dump_file (p, -1, 1);
    }

  write_eot ();
  close_archive ();
  names_notfound ();
}

/* Catenate file p to the archive without creating a header for it.  It had
   better be a tar file or the archive is screwed */

void
append_file (p)
     char *p;
{
  int fd;
  struct stat statbuf;
  long bytes_left;
  union record *start;
  long bufsiz, count;

  if (0 != stat (p, &statbuf) || (fd = open (p, O_RDONLY | O_BINARY)) < 0)
    {
      msg_perror ("can't open file %s", p);
      errors++;
      return;
    }

  bytes_left = statbuf.st_size;

  while (bytes_left > 0)
    {
      start = findrec ();
      bufsiz = endofrecs ()->charptr - start->charptr;
      if (bytes_left < bufsiz)
	{
	  bufsiz = bytes_left;
	  count = bufsiz % RECORDSIZE;
	  if (count)
	    bzero (start->charptr + bytes_left, (int) (RECORDSIZE - count));
	}
      count = read (fd, start->charptr, bufsiz);
      if (count < 0)
	{
	  msg_perror ("read error at byte %ld reading %d bytes in file %s", statbuf.st_size - bytes_left, bufsiz, p);
	  exit (EX_ARGSBAD);	/* FOO */
	}
      bytes_left -= count;
      userec (start + (count - 1) / RECORDSIZE);
      if (count != bufsiz)
	{
	  msg ("%s: file shrunk by %d bytes, yark!", p, bytes_left);
	  abort ();
	}
    }
  (void) close (fd);
}

#ifdef DONTDEF
bprint (fp, buf, num)
     FILE *fp;
     char *buf;
{
  int c;

  if (num == 0 || num == -1)
    return;
  fputs (" '", fp);
  while (num--)
    {
      c = *buf++;
      if (c == '\\')
	fputs ("\\\\", fp);
      else if (c >= ' ' && c <= '~')
	putc (c, fp);
      else
	switch (c)
	  {
	  case '\n':
	    fputs ("\\n", fp);
	    break;
	  case '\r':
	    fputs ("\\r", fp);
	    break;
	  case '\b':
	    fputs ("\\b", fp);
	    break;
	  case '\0':
	    /* fputs("\\-",fp); */
	    break;
	  default:
	    fprintf (fp, "\\%03o", c);
	    break;
	  }
    }
  fputs ("'\n", fp);
}

#endif

int number_of_blocks_read = 0;

int number_of_new_records = 0;
int number_of_records_needed = 0;

union record *new_block = 0;
union record *save_block = 0;

void
junk_archive ()
{
  int found_stuff = 0;
  int status = 3;
  int prev_status;
  struct name *name;

  /* int dummy_head; */
  int number_of_records_to_skip = 0;
  int number_of_records_to_keep = 0;
  int number_of_kept_records_in_block;
  int sub_status;
  extern int write_archive_to_stdout;

  /* fprintf(stderr,"Junk files\n"); */
  name_gather ();
  open_archive (2);

  while (!found_stuff)
    {
      prev_status = status;
      status = read_header ();
      switch (status)
	{
	case EOF:
	  found_stuff = 1;
	  break;

	case 0:
	  userec (head);
	  switch (prev_status)
	    {
	    case 3:
	      msg ("This doesn't look like a tar archive.");
	      /* FALL THROUGH */
	    case 2:
	    case 1:
	      msg ("Skipping to next header");
	      /* FALL THROUGH */
	    case 0:
	      break;
	    }
	  break;

	case 1:
	  /* head->header.name[NAMSIZ-1] = '\0'; */
	  /* fprintf(stderr,"file %s\n",head->header.name); */
	  if ((name = name_scan (current_file_name)) == (struct name *) 0)
	    {
	      userec (head);
	      /* fprintf(stderr,"Skip %ld\n",(long)(hstat.st_size)); */
	      if (head->header.isextended)
		skip_extended_headers ();
	      skip_file ((long) (hstat.st_size));
	      break;
	    }
	  name->found = 1;
	  found_stuff = 2;
	  break;

	case 2:
	  found_stuff = 1;
	  break;
	}
    }
  /* fprintf(stderr,"Out of first loop\n"); */

  if (found_stuff != 2)
    {
      write_eot ();
      close_archive ();
      names_notfound ();
      return;
    }

  if (write_archive_to_stdout)
    write_archive_to_stdout = 0;
  new_block = (union record *) malloc (blocksize);
  if (new_block == 0)
    {
      msg ("Can't allocate secondary block of %d bytes", blocksize);
      exit (EX_SYSTEM);
    }

  /* Save away records before this one in this block */
  number_of_new_records = ar_record - ar_block;
  number_of_records_needed = blocking - number_of_new_records;
  if (number_of_new_records)
    bcopy ((void *) ar_block, (void *) new_block, (number_of_new_records) * RECORDSIZE);

  /* fprintf(stderr,"Saved %d recs, need %d more\n",number_of_new_records,number_of_records_needed); */
  userec (head);
  if (head->header.isextended)
    skip_extended_headers ();
  skip_file ((long) (hstat.st_size));
  found_stuff = 0;
  /* goto flush_file; */

  for (;;)
    {
      /* Fill in a block */
      /* another_file: */
      if (ar_record == ar_last)
	{
	  /* fprintf(stderr,"New block\n"); */
	  flush_archive ();
	  number_of_blocks_read++;
	}
      sub_status = read_header ();
      /* fprintf(stderr,"Header type %d\n",sub_status); */

      if (sub_status == 2 && f_ignorez)
	{
	  userec (head);
	  continue;
	}
      if (sub_status == EOF || sub_status == 2)
	{
	  found_stuff = 1;
	  bzero (new_block[number_of_new_records].charptr, RECORDSIZE * number_of_records_needed);
	  number_of_new_records += number_of_records_needed;
	  number_of_records_needed = 0;
	  write_block (0);
	  break;
	}

      if (sub_status == 0)
	{
	  msg ("Deleting non-header from archive.");
	  userec (head);
	  continue;
	}

      /* Found another header.  Yipee! */
      /* head->header.name[NAMSIZ-1] = '\0'; */
      /* fprintf(stderr,"File %s ",head->header.name); */
      if (name = name_scan (current_file_name))
	{
	  name->found = 1;
	  /* fprintf(stderr,"Flush it\n"); */
	  /* flush_file: */
	  /* decode_header(head,&hstat,&dummy_head,0); */
	  userec (head);
	  number_of_records_to_skip = (hstat.st_size + RECORDSIZE - 1) / RECORDSIZE;
	  /* fprintf(stderr,"Flushing %d recs from %s\n",number_of_records_to_skip,head->header.name); */

	  while (ar_last - ar_record <= number_of_records_to_skip)
	    {

	      /* fprintf(stderr,"Block: %d <= %d  ",ar_last-ar_record,number_of_records_to_skip); */
	      number_of_records_to_skip -= (ar_last - ar_record);
	      flush_archive ();
	      number_of_blocks_read++;
	      /* fprintf(stderr,"Block %d left\n",number_of_records_to_skip); */
	    }
	  ar_record += number_of_records_to_skip;
	  /* fprintf(stderr,"Final %d\n",number_of_records_to_skip); */
	  number_of_records_to_skip = 0;
	  continue;
	}

      /* copy_header: */
      new_block[number_of_new_records] = *head;
      number_of_new_records++;
      number_of_records_needed--;
      number_of_records_to_keep = (hstat.st_size + RECORDSIZE - 1) / RECORDSIZE;
      userec (head);
      if (number_of_records_needed == 0)
	write_block (1);
      /* copy_data: */
      number_of_kept_records_in_block = ar_last - ar_record;
      if (number_of_kept_records_in_block > number_of_records_to_keep)
	number_of_kept_records_in_block = number_of_records_to_keep;

      /* fprintf(stderr,"Need %d kept_in %d keep %d\n",blocking,number_of_kept_records_in_block,number_of_records_to_keep); */

      while (number_of_records_to_keep)
	{
	  int n;

	  if (ar_record == ar_last)
	    {
	      /* fprintf(stderr,"Flush. . .\n"); */
	      fl_read ();
	      number_of_blocks_read++;
	      ar_record = ar_block;
	      number_of_kept_records_in_block = blocking;
	      if (number_of_kept_records_in_block > number_of_records_to_keep)
		number_of_kept_records_in_block = number_of_records_to_keep;
	    }
	  n = number_of_kept_records_in_block;
	  if (n > number_of_records_needed)
	    n = number_of_records_needed;

	  /* fprintf(stderr,"Copying %d\n",n); */
	  bcopy ((void *) ar_record, (void *) (new_block + number_of_new_records), n * RECORDSIZE);
	  number_of_new_records += n;
	  number_of_records_needed -= n;
	  ar_record += n;
	  number_of_records_to_keep -= n;
	  number_of_kept_records_in_block -= n;
	  /* fprintf(stderr,"Now new %d  need %d  keep %d  keep_in %d rec %d/%d\n",
 number_of_new_records,number_of_records_needed,number_of_records_to_keep,
 number_of_kept_records_in_block,ar_record-ar_block,ar_last-ar_block); */

	  if (number_of_records_needed == 0)
	    {
	      write_block (1);
	    }
	}
    }

  write_eot ();
  close_archive ();
  names_notfound ();
}

void
write_block (f)
     int f;
{
  /* fprintf(stderr,"Write block\n"); */
  /* We've filled out a block.  Write it out. */

  /* Backspace back to where we started. . . */
  if (archive != STDIN)
    (void) move_arch (-(number_of_blocks_read + 1));

  save_block = ar_block;
  ar_block = new_block;

  if (archive == STDIN)
    archive = STDOUT;
  fl_write ();

  if (archive == STDOUT)
    archive = STDIN;
  ar_block = save_block;

  if (f)
    {
      /* Move the tape head back to where we were */
      if (archive != STDIN)
	(void) move_arch (number_of_blocks_read);
      number_of_blocks_read--;
    }

  number_of_records_needed = blocking;
  number_of_new_records = 0;
}

/* Move archive descriptor by n blocks worth.  If n is positive we move
   forward, else we move negative.   If its a tape, MTIOCTOP had better
   work.  If its something else, we try to seek on it.  If we can't
   seek, we lose! */
int
move_arch (n)
     int n;
{
  long cur;

#ifdef MTIOCTOP
  struct mtop t;
  int er;

  if (n > 0)
    {
      t.mt_op = MTFSR;
      t.mt_count = n;
    }
  else
    {
      t.mt_op = MTBSR;
      t.mt_count = -n;
    }
  if ((er = rmtioctl (archive, MTIOCTOP, &t)) >= 0)
    return 1;
  if (errno == EIO && (er = rmtioctl (archive, MTIOCTOP, &t)) >= 0)
    return 1;
#endif

  cur = rmtlseek (archive, 0L, 1);
  cur += blocksize * n;

  /* fprintf(stderr,"Fore to %x\n",cur); */
  if (rmtlseek (archive, cur, 0) != cur)
    {
      /* Lseek failed.  Try a different method */
      msg ("Couldn't re-position archive file.");
      exit (EX_BADARCH);
    }
  return 3;
}