/* Diff files from a tar archive.
   Copyright (C) 1988, 1992, 1993 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.  */

/*
 * Diff files from a tar archive.
 *
 * Written 30 April 1987 by John Gilmore, ihnp4!hoptoad!gnu.
 */

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

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

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

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

#ifndef S_ISLNK
#define lstat stat
#endif

extern void *valloc ();

extern union record *head;	/* Points to current tape header */
extern struct stat hstat;	/* Stat struct corresponding */
extern int head_standard;	/* Tape header is in ANSI format */

void decode_header ();
void diff_sparse_files ();
void fill_in_sparse_array ();
void fl_read ();
long from_oct ();
int do_stat ();
extern void print_header ();
int read_header ();
void saverec ();
void sigh ();
extern void skip_file ();
extern void skip_extended_headers ();
int wantbytes ();

extern FILE *msg_file;

int now_verifying = 0;		/* Are we verifying at the moment? */

int diff_fd;			/* Descriptor of file we're diffing */

char *diff_buf = 0;		/* Pointer to area for reading
					   file contents into */

char *diff_dir;			/* Directory contents for LF_DUMPDIR */

int different = 0;

/*struct sp_array *sparsearray;
int 		sp_ar_size = 10;*/
/*
 * Initialize for a diff operation
 */
void
diff_init ()
{
  /*NOSTRICT*/
  diff_buf = (char *) valloc ((unsigned) blocksize);
  if (!diff_buf)
    {
      msg ("could not allocate memory for diff buffer of %d bytes",
	   blocksize);
      exit (EX_ARGSBAD);
    }
}

/*
 * Diff a file against the archive.
 */
void
diff_archive ()
{
  register char *data;
  int check, namelen;
  int err;
  long offset;
  struct stat filestat;
  int compare_chunk ();
  int compare_dir ();
  int no_op ();
#ifndef __MSDOS__
  dev_t dev;
  ino_t ino;
#endif
  char *get_dir_contents ();
  long from_oct ();

  errno = EPIPE;		/* FIXME, remove perrors */

  saverec (&head);		/* Make sure it sticks around */
  userec (head);		/* And go past it in the archive */
  decode_header (head, &hstat, &head_standard, 1);	/* Snarf fields */

  /* Print the record from 'head' and 'hstat' */
  if (f_verbose)
    {
      if (now_verifying)
	fprintf (msg_file, "Verify ");
      print_header ();
    }

  switch (head->header.linkflag)
    {

    default:
      msg ("Unknown file type '%c' for %s, diffed as normal file",
	   head->header.linkflag, current_file_name);
      /* FALL THRU */

    case LF_OLDNORMAL:
    case LF_NORMAL:
    case LF_SPARSE:
    case LF_CONTIG:
      /*
		 * Appears to be a file.
		 * See if it's really a directory.
		 */
      namelen = strlen (current_file_name) - 1;
      if (current_file_name[namelen] == '/')
	goto really_dir;


      if (do_stat (&filestat))
	{
	  if (head->header.isextended)
	    skip_extended_headers ();
	  skip_file ((long) hstat.st_size);
	  different++;
	  goto quit;
	}

      if (!S_ISREG (filestat.st_mode))
	{
	  fprintf (msg_file, "%s: not a regular file\n",
		   current_file_name);
	  skip_file ((long) hstat.st_size);
	  different++;
	  goto quit;
	}

      filestat.st_mode &= 07777;
      if (filestat.st_mode != hstat.st_mode)
	sigh ("mode");
      if (filestat.st_uid != hstat.st_uid)
	sigh ("uid");
      if (filestat.st_gid != hstat.st_gid)
	sigh ("gid");
      if (filestat.st_mtime != hstat.st_mtime)
	sigh ("mod time");
      if (head->header.linkflag != LF_SPARSE &&
	  filestat.st_size != hstat.st_size)
	{
	  sigh ("size");
	  skip_file ((long) hstat.st_size);
	  goto quit;
	}

      diff_fd = open (current_file_name, O_NDELAY | O_RDONLY | O_BINARY);

      if (diff_fd < 0 && !f_absolute_paths)
	{
	  char tmpbuf[NAMSIZ + 2];

	  tmpbuf[0] = '/';
	  strcpy (&tmpbuf[1], current_file_name);
	  diff_fd = open (tmpbuf, O_NDELAY | O_RDONLY);
	}
      if (diff_fd < 0)
	{
	  msg_perror ("cannot open %s", current_file_name);
	  if (head->header.isextended)
	    skip_extended_headers ();
	  skip_file ((long) hstat.st_size);
	  different++;
	  goto quit;
	}
      /*
		 * Need to treat sparse files completely differently here.
		 */
      if (head->header.linkflag == LF_SPARSE)
	diff_sparse_files (hstat.st_size);
      else
	wantbytes ((long) (hstat.st_size), compare_chunk);

      check = close (diff_fd);
      if (check < 0)
	msg_perror ("Error while closing %s", current_file_name);

    quit:
      break;

#ifndef __MSDOS__
    case LF_LINK:
      if (do_stat (&filestat))
	break;
      dev = filestat.st_dev;
      ino = filestat.st_ino;
      err = stat (current_link_name, &filestat);
      if (err < 0)
	{
	  if (errno == ENOENT)
	    {
	      fprintf (msg_file, "%s: does not exist\n", current_file_name);
	    }
	  else
	    {
	      msg_perror ("cannot stat file %s", current_file_name);
	    }
	  different++;
	  break;
	}
      if (filestat.st_dev != dev || filestat.st_ino != ino)
	{
	  fprintf (msg_file, "%s not linked to %s\n", current_file_name, current_link_name);
	  break;
	}
      break;
#endif

#ifdef S_ISLNK
    case LF_SYMLINK:
      {
	char linkbuf[NAMSIZ + 3];
	check = readlink (current_file_name, linkbuf,
			  (sizeof linkbuf) - 1);

	if (check < 0)
	  {
	    if (errno == ENOENT)
	      {
		fprintf (msg_file,
			 "%s: no such file or directory\n",
			 current_file_name);
	      }
	    else
	      {
		msg_perror ("cannot read link %s", current_file_name);
	      }
	    different++;
	    break;
	  }

	linkbuf[check] = '\0';	/* Null-terminate it */
	if (strncmp (current_link_name, linkbuf, check) != 0)
	  {
	    fprintf (msg_file, "%s: symlink differs\n",
		     current_link_name);
	    different++;
	  }
      }
      break;
#endif

#ifdef S_IFCHR
    case LF_CHR:
      hstat.st_mode |= S_IFCHR;
      goto check_node;
#endif

#ifdef S_IFBLK
      /* If local system doesn't support block devices, use default case */
    case LF_BLK:
      hstat.st_mode |= S_IFBLK;
      goto check_node;
#endif

#ifdef S_ISFIFO
      /* If local system doesn't support FIFOs, use default case */
    case LF_FIFO:
#ifdef S_IFIFO
      hstat.st_mode |= S_IFIFO;
#endif
      hstat.st_rdev = 0;	/* FIXME, do we need this? */
      goto check_node;
#endif

    check_node:
      /* FIXME, deal with umask */
      if (do_stat (&filestat))
	break;
      if (hstat.st_rdev != filestat.st_rdev)
	{
	  fprintf (msg_file, "%s: device numbers changed\n", current_file_name);
	  different++;
	  break;
	}
#ifdef S_IFMT
      if (hstat.st_mode != filestat.st_mode)
#else /* POSIX lossage */
      if ((hstat.st_mode & 07777) != (filestat.st_mode & 07777))
#endif
	{
	  fprintf (msg_file, "%s: mode or device-type changed\n", current_file_name);
	  different++;
	  break;
	}
      break;

    case LF_DUMPDIR:
      data = diff_dir = get_dir_contents (current_file_name, 0);
      if (data)
	{
	  wantbytes ((long) (hstat.st_size), compare_dir);
	  free (data);
	}
      else
	wantbytes ((long) (hstat.st_size), no_op);
      /* FALL THROUGH */

    case LF_DIR:
      /* Check for trailing / */
      namelen = strlen (current_file_name) - 1;
    really_dir:
      while (namelen && current_file_name[namelen] == '/')
	current_file_name[namelen--] = '\0';	/* Zap / */

      if (do_stat (&filestat))
	break;
      if (!S_ISDIR (filestat.st_mode))
	{
	  fprintf (msg_file, "%s is no longer a directory\n", current_file_name);
	  different++;
	  break;
	}
      if ((filestat.st_mode & 07777) != (hstat.st_mode & 07777))
	sigh ("mode");
      break;

    case LF_VOLHDR:
      break;

    case LF_MULTIVOL:
      namelen = strlen (current_file_name) - 1;
      if (current_file_name[namelen] == '/')
	goto really_dir;

      if (do_stat (&filestat))
	break;

      if (!S_ISREG (filestat.st_mode))
	{
	  fprintf (msg_file, "%s: not a regular file\n",
		   current_file_name);
	  skip_file ((long) hstat.st_size);
	  different++;
	  break;
	}

      filestat.st_mode &= 07777;
      offset = from_oct (1 + 12, head->header.offset);
      if (filestat.st_size != hstat.st_size + offset)
	{
	  sigh ("size");
	  skip_file ((long) hstat.st_size);
	  different++;
	  break;
	}

      diff_fd = open (current_file_name, O_NDELAY | O_RDONLY | O_BINARY);

      if (diff_fd < 0)
	{
	  msg_perror ("cannot open file %s", current_file_name);
	  skip_file ((long) hstat.st_size);
	  different++;
	  break;
	}
      err = lseek (diff_fd, offset, 0);
      if (err != offset)
	{
	  msg_perror ("cannot seek to %ld in file %s", offset, current_file_name);
	  different++;
	  break;
	}

      wantbytes ((long) (hstat.st_size), compare_chunk);

      check = close (diff_fd);
      if (check < 0)
	{
	  msg_perror ("Error while closing %s", current_file_name);
	}
      break;

    }

  /* We don't need to save it any longer. */
  saverec ((union record **) 0);/* Unsave it */
}

int
compare_chunk (bytes, buffer)
     long bytes;
     char *buffer;
{
  int err;

  err = read (diff_fd, diff_buf, bytes);
  if (err != bytes)
    {
      if (err < 0)
	{
	  msg_perror ("can't read %s", current_file_name);
	}
      else
	{
	  fprintf (msg_file, "%s: could only read %d of %d bytes\n", current_file_name, err, bytes);
	}
      different++;
      return -1;
    }
  if (bcmp (buffer, diff_buf, bytes))
    {
      fprintf (msg_file, "%s: data differs\n", current_file_name);
      different++;
      return -1;
    }
  return 0;
}

int
compare_dir (bytes, buffer)
     long bytes;
     char *buffer;
{
  if (bcmp (buffer, diff_dir, bytes))
    {
      fprintf (msg_file, "%s: data differs\n", current_file_name);
      different++;
      return -1;
    }
  diff_dir += bytes;
  return 0;
}

/*
 * Sigh about something that differs.
 */
void
sigh (what)
     char *what;
{

  fprintf (msg_file, "%s: %s differs\n",
	   current_file_name, what);
}

void
verify_volume ()
{
  int status;
#ifdef MTIOCTOP
  struct mtop t;
  int er;
#endif

  if (!diff_buf)
    diff_init ();
#ifdef MTIOCTOP
  t.mt_op = MTBSF;
  t.mt_count = 1;
  if ((er = rmtioctl (archive, MTIOCTOP, &t)) < 0)
    {
      if (errno != EIO || (er = rmtioctl (archive, MTIOCTOP, &t)) < 0)
	{
#endif
	  if (rmtlseek (archive, 0L, 0) != 0)
	    {
	      /* Lseek failed.  Try a different method */
	      msg_perror ("Couldn't rewind archive file for verify");
	      return;
	    }
#ifdef MTIOCTOP
	}
    }
#endif
  ar_reading = 1;
  now_verifying = 1;
  fl_read ();
  for (;;)
    {
      status = read_header ();
      if (status == 0)
	{
	  unsigned n;

	  n = 0;
	  do
	    {
	      n++;
	      status = read_header ();
	    }
	  while (status == 0);
	  msg ("VERIFY FAILURE: %d invalid header%s detected!", n, n == 1 ? "" : "s");
	}
      if (status == 2 || status == EOF)
	break;
      diff_archive ();
    }
  ar_reading = 0;
  now_verifying = 0;

}

int
do_stat (statp)
     struct stat *statp;
{
  int err;

  err = f_follow_links ? stat (current_file_name, statp) : lstat (current_file_name, statp);
  if (err < 0)
    {
      if (errno == ENOENT)
	{
	  fprintf (msg_file, "%s: does not exist\n", current_file_name);
	}
      else
	msg_perror ("can't stat file %s", current_file_name);
      /*		skip_file((long)hstat.st_size);
		different++;*/
      return 1;
    }
  else
    return 0;
}

/*
 * JK
 * Diff'ing a sparse file with its counterpart on the tar file is a
 * bit of a different story than a normal file.  First, we must know
 * what areas of the file to skip through, i.e., we need to contruct
 * a sparsearray, which will hold all the information we need.  We must
 * compare small amounts of data at a time as we find it.
 */

void
diff_sparse_files (filesize)
     int filesize;

{
  int sparse_ind = 0;
  char *buf;
  int buf_size = RECORDSIZE;
  union record *datarec;
  int err;
  long numbytes;
  /*	int		amt_read = 0;*/
  int size = filesize;

  buf = (char *) ck_malloc (buf_size * sizeof (char));

  fill_in_sparse_array ();


  while (size > 0)
    {
      datarec = findrec ();
      if (!sparsearray[sparse_ind].numbytes)
	break;

      /*
		 * 'numbytes' is nicer to write than
		 * 'sparsearray[sparse_ind].numbytes' all the time ...
		 */
      numbytes = sparsearray[sparse_ind].numbytes;

      lseek (diff_fd, sparsearray[sparse_ind].offset, 0);
      /*
		 * take care to not run out of room in our buffer
		 */
      while (buf_size < numbytes)
	{
	  buf = (char *) ck_realloc (buf, buf_size * 2 * sizeof (char));
	  buf_size *= 2;
	}
      while (numbytes > RECORDSIZE)
	{
	  if ((err = read (diff_fd, buf, RECORDSIZE)) != RECORDSIZE)
	    {
	      if (err < 0)
		msg_perror ("can't read %s", current_file_name);
	      else
		fprintf (msg_file, "%s: could only read %d of %d bytes\n",
			 current_file_name, err, numbytes);
	      break;
	    }
	  if (bcmp (buf, datarec->charptr, RECORDSIZE))
	    {
	      different++;
	      break;
	    }
	  numbytes -= err;
	  size -= err;
	  userec (datarec);
	  datarec = findrec ();
	}
      if ((err = read (diff_fd, buf, numbytes)) != numbytes)
	{
	  if (err < 0)
	    msg_perror ("can't read %s", current_file_name);
	  else
	    fprintf (msg_file, "%s: could only read %d of %d bytes\n",
		     current_file_name, err, numbytes);
	  break;
	}

      if (bcmp (buf, datarec->charptr, numbytes))
	{
	  different++;
	  break;
	}
      /*		amt_read += numbytes;
		if (amt_read >= RECORDSIZE) {
			amt_read = 0;
			userec(datarec);
			datarec = findrec();
		}*/
      userec (datarec);
      sparse_ind++;
      size -= numbytes;
    }
  /*
	 * if the number of bytes read isn't the
	 * number of bytes supposedly in the file,
	 * they're different
	 */
  /*	if (amt_read != filesize)
		different++;*/
  userec (datarec);
  free (sparsearray);
  if (different)
    fprintf (msg_file, "%s: data differs\n", current_file_name);

}

/*
 * JK
 * This routine should be used more often than it is ... look into
 * that.  Anyhow, what it does is translate the sparse information
 * on the header, and in any subsequent extended headers, into an
 * array of structures with true numbers, as opposed to character
 * strings.  It simply makes our life much easier, doing so many
 * comparisong and such.
 */
void
fill_in_sparse_array ()
{
  int ind;

  /*
	 * allocate space for our scratch space; it's initially
	 * 10 elements long, but can change in this routine if
	 * necessary
	 */
  sp_array_size = 10;
  sparsearray = (struct sp_array *) ck_malloc (sp_array_size * sizeof (struct sp_array));

  /*
	 * there are at most five of these structures in the header
	 * itself; read these in first
	 */
  for (ind = 0; ind < SPARSE_IN_HDR; ind++)
    {
      if (!head->header.sp[ind].numbytes)
	break;
      sparsearray[ind].offset =
	from_oct (1 + 12, head->header.sp[ind].offset);
      sparsearray[ind].numbytes =
	from_oct (1 + 12, head->header.sp[ind].numbytes);
    }
  /*
	 * if the header's extended, we gotta read in exhdr's till
	 * we're done
	 */
  if (head->header.isextended)
    {
      /* how far into the sparsearray we are 'so far' */
      static int so_far_ind = SPARSE_IN_HDR;
      union record *exhdr;

      for (;;)
	{
	  exhdr = findrec ();
	  for (ind = 0; ind < SPARSE_EXT_HDR; ind++)
	    {
	      if (ind + so_far_ind > sp_array_size - 1)
		{
		  /*
 				 * we just ran out of room in our
				 *  scratch area - realloc it
 				 */
		  sparsearray = (struct sp_array *)
		    ck_realloc (sparsearray,
			     sp_array_size * 2 * sizeof (struct sp_array));
		  sp_array_size *= 2;
		}
	      /*
			 * convert the character strings into longs
			 */
	      sparsearray[ind + so_far_ind].offset =
		from_oct (1 + 12, exhdr->ext_hdr.sp[ind].offset);
	      sparsearray[ind + so_far_ind].numbytes =
		from_oct (1 + 12, exhdr->ext_hdr.sp[ind].numbytes);
	    }
	  /*
		 * if this is the last extended header for this
		 * file, we can stop
		 */
	  if (!exhdr->ext_hdr.isextended)
	    break;
	  else
	    {
	      so_far_ind += SPARSE_EXT_HDR;
	      userec (exhdr);
	    }
	}
      /* be sure to skip past the last one  */
      userec (exhdr);
    }
}