2005-03-04  Sergey Poznyakoff  <gray@Mirddin.farlep.net>

	* src/sparse.c (sparse_scan_file): Bugfix. offset had

	incorrect type.

2005-02-02  Sergey Poznyakoff  <gray@Mirddin.farlep.net>

	* src/sparse.c: Extract sparse files even if the output

	fd is not seekable.

--- src/sparse.c	6 Sep 2004 14:28:56 -0000	1.10

+++ src/sparse.c	3 Mar 2005 23:13:30 -0000	1.12

@@ -1,6 +1,6 @@

 /* Functions for dealing with sparse files

-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.

+   Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.

    This program is free software; you can redistribute it and/or modify it

    under the terms of the GNU General Public License as published by the

@@ -46,6 +46,9 @@ struct tar_sparse_optab

 struct tar_sparse_file

 {

   int fd;                           /* File descriptor */

+  bool seekable;                    /* Is fd seekable? */

+  size_t offset;                    /* Current offset in fd if seekable==false.

+				       Otherwise unused */

   size_t dumped_size;               /* Number of bytes actually written

 				       to the archive */

   struct tar_stat_info *stat_info;  /* Information about the file */

@@ -54,6 +57,39 @@ struct tar_sparse_file

 				       reqiure */

 };

+/* Dump zeros to file->fd until offset is reached. It is used instead of

+   lseek if the output file is not seekable */

+static long

+dump_zeros (struct tar_sparse_file *file, off_t offset)

+{

+  char buf[BLOCKSIZE];

+  

+  if (offset - file->offset < 0)

+    {

+      errno = EINVAL;

+      return -1;

+    }

+

+  memset (buf, 0, sizeof buf);

+  while (file->offset < offset)

+    {

+      size_t size = offset - file->offset;

+      size_t wrbytes;

+      

+      if (size > sizeof buf)

+	size = sizeof buf;

+      wrbytes = write (file->fd, buf, size);

+      if (wrbytes <= 0)

+	{

+	  if (wrbytes == 0)

+	    errno = EINVAL;

+	  return -1;

+	}

+      file->offset += wrbytes;

+    }

+  return file->offset;

+}

+

 static bool

 tar_sparse_member_p (struct tar_sparse_file *file)

 {

@@ -130,9 +166,16 @@ tar_sparse_fixup_header (struct tar_spar

 static bool

-lseek_or_error (struct tar_sparse_file *file, off_t offset, int whence)

+lseek_or_error (struct tar_sparse_file *file, off_t offset)

 {

-  if (lseek (file->fd, offset, whence) < 0)

+  off_t off;

+

+  if (file->seekable)

+    off = lseek (file->fd, offset, SEEK_SET);

+  else

+    off = dump_zeros (file, offset);

+  

+  if (off < 0)

     {

       seek_diag_details (file->stat_info->orig_file_name, offset);

       return false;

@@ -182,10 +225,10 @@ sparse_scan_file (struct tar_sparse_file

 {

   static char buffer[BLOCKSIZE];

   size_t count;

-  size_t offset = 0;

+  off_t offset = 0;

   struct sp_array sp = {0, 0};

-  if (!lseek_or_error (file, 0, SEEK_SET))

+  if (!lseek_or_error (file, 0))

     return false;

   clear_block (buffer);

@@ -269,8 +312,7 @@ sparse_dump_region (struct tar_sparse_fi

   union block *blk;

   off_t bytes_left = file->stat_info->sparse_map[i].numbytes;

-  if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset,

-		       SEEK_SET))

+  if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset))

     return false;

   while (bytes_left > 0)

@@ -304,8 +346,7 @@ sparse_extract_region (struct tar_sparse

 {

   size_t write_size;

-  if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset,

-		       SEEK_SET))

+  if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset))

     return false;

   write_size = file->stat_info->sparse_map[i].numbytes;

@@ -313,7 +354,7 @@ sparse_extract_region (struct tar_sparse

   if (write_size == 0)

     {

       /* Last block of the file is a hole */

-      if (sys_truncate (file->fd))

+      if (file->seekable && sys_truncate (file->fd))

 	truncate_warn (file->stat_info->orig_file_name);

     }

   else while (write_size > 0)

@@ -330,6 +371,7 @@ sparse_extract_region (struct tar_sparse

       count = full_write (file->fd, blk->buffer, wrbytes);

       write_size -= count;

       file->dumped_size += count;

+      file->offset += count;

       if (count != wrbytes)

 	{

 	  write_error_details (file->stat_info->orig_file_name,

@@ -351,7 +393,9 @@ sparse_dump_file (int fd, struct tar_sta

   file.stat_info = st;

   file.fd = fd;

-

+  file.seekable = true; /* File *must* be seekable for dump to work */

+  file.offset = 0;

+  

   if (!sparse_select_optab (&file)

       || !tar_sparse_init (&file))

     return dump_status_not_implemented;

@@ -414,7 +458,9 @@ sparse_extract_file (int fd, struct tar_

   file.stat_info = st;

   file.fd = fd;

-

+  file.seekable = lseek (fd, 0, SEEK_SET) == 0;

+  file.offset = 0;

+  

   if (!sparse_select_optab (&file)

       || !tar_sparse_init (&file))

     return dump_status_not_implemented;

@@ -450,7 +496,7 @@ static char diff_buffer[BLOCKSIZE];

 static bool

 check_sparse_region (struct tar_sparse_file *file, off_t beg, off_t end)

 {

-  if (!lseek_or_error (file, beg, SEEK_SET))

+  if (!lseek_or_error (file, beg))

     return false;

   while (beg < end)

@@ -486,8 +532,7 @@ check_data_region (struct tar_sparse_fil

 {

   size_t size_left;

-  if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset,

-		       SEEK_SET))

+  if (!lseek_or_error (file, file->stat_info->sparse_map[i].offset))

     return false;

   size_left = file->stat_info->sparse_map[i].numbytes;

   while (size_left > 0)