/* Functions for dealing with sparse files
- Copyright (C) 2003, 2004, 2005, 2006, 2007, 2010 Free Software
- Foundation, Inc.
+ Copyright 2003-2007, 2010, 2013-2016 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
Public License for more details.
You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <system.h>
#include <inttostr.h>
st->sparse_map_avail = avail + 1;
}
-/* Scan the sparse file and create its map */
+/* Scan the sparse file byte-by-byte and create its map. */
static bool
-sparse_scan_file (struct tar_sparse_file *file)
+sparse_scan_file_raw (struct tar_sparse_file *file)
{
struct tar_stat_info *st = file->stat_info;
int fd = file->fd;
st->archive_file_size = 0;
- if (ST_NBLOCKS (st->stat) == 0)
- offset = st->stat.st_size;
- else
- {
- if (!tar_sparse_scan (file, scan_begin, NULL))
- return false;
-
- while ((count = safe_read (fd, buffer, sizeof buffer)) != 0
- && count != SAFE_READ_ERROR)
- {
- /* Analyze the block. */
- if (zero_block_p (buffer, count))
- {
- if (sp.numbytes)
- {
- sparse_add_map (st, &sp);
- sp.numbytes = 0;
- if (!tar_sparse_scan (file, scan_block, NULL))
- return false;
- }
- }
- else
- {
- if (sp.numbytes == 0)
- sp.offset = offset;
- sp.numbytes += count;
- st->archive_file_size += count;
- if (!tar_sparse_scan (file, scan_block, buffer))
- return false;
- }
+ if (!tar_sparse_scan (file, scan_begin, NULL))
+ return false;
- offset += count;
- }
+ while ((count = blocking_read (fd, buffer, sizeof buffer)) != 0
+ && count != SAFE_READ_ERROR)
+ {
+ /* Analyze the block. */
+ if (zero_block_p (buffer, count))
+ {
+ if (sp.numbytes)
+ {
+ sparse_add_map (st, &sp);
+ sp.numbytes = 0;
+ if (!tar_sparse_scan (file, scan_block, NULL))
+ return false;
+ }
+ }
+ else
+ {
+ if (sp.numbytes == 0)
+ sp.offset = offset;
+ sp.numbytes += count;
+ st->archive_file_size += count;
+ if (!tar_sparse_scan (file, scan_block, buffer))
+ return false;
+ }
+
+ offset += count;
}
+ /* save one more sparse segment of length 0 to indicate that
+ the file ends with a hole */
if (sp.numbytes == 0)
sp.offset = offset;
return tar_sparse_scan (file, scan_end, NULL);
}
+static bool
+sparse_scan_file_wholesparse (struct tar_sparse_file *file)
+{
+ struct tar_stat_info *st = file->stat_info;
+ struct sp_array sp = {0, 0};
+
+ /* Note that this function is called only for truly sparse files of size >= 1
+ block size (checked via ST_IS_SPARSE before). See the thread
+ http://www.mail-archive.com/bug-tar@gnu.org/msg04209.html for more info */
+ if (ST_NBLOCKS (st->stat) == 0)
+ {
+ st->archive_file_size = 0;
+ sp.offset = st->stat.st_size;
+ sparse_add_map (st, &sp);
+ return true;
+ }
+
+ return false;
+}
+
+#ifdef SEEK_HOLE
+/* Try to engage SEEK_HOLE/SEEK_DATA feature. */
+static bool
+sparse_scan_file_seek (struct tar_sparse_file *file)
+{
+ struct tar_stat_info *st = file->stat_info;
+ int fd = file->fd;
+ struct sp_array sp = {0, 0};
+ off_t offset = 0;
+ off_t data_offset;
+ off_t hole_offset;
+
+ st->archive_file_size = 0;
+
+ for (;;)
+ {
+ /* locate first chunk of data */
+ data_offset = lseek (fd, offset, SEEK_DATA);
+
+ if (data_offset == (off_t)-1)
+ /* ENXIO == EOF; error otherwise */
+ {
+ if (errno == ENXIO)
+ {
+ /* file ends with hole, add one more empty chunk of data */
+ sp.numbytes = 0;
+ sp.offset = st->stat.st_size;
+ sparse_add_map (st, &sp);
+ return true;
+ }
+ return false;
+ }
+
+ hole_offset = lseek (fd, data_offset, SEEK_HOLE);
+
+ /* according to specs, if FS does not fully support
+ SEEK_DATA/SEEK_HOLE it may just implement kind of "wrapper" around
+ classic lseek() call. We must detect it here and try to use other
+ hole-detection methods. */
+ if (offset == 0 /* first loop */
+ && data_offset == 0
+ && hole_offset == st->stat.st_size)
+ {
+ lseek (fd, 0, SEEK_SET);
+ return false;
+ }
+
+ sp.offset = data_offset;
+ sp.numbytes = hole_offset - data_offset;
+ sparse_add_map (st, &sp);
+
+ st->archive_file_size += sp.numbytes;
+ offset = hole_offset;
+ }
+
+ return true;
+}
+#endif
+
+static bool
+sparse_scan_file (struct tar_sparse_file *file)
+{
+ /* always check for completely sparse files */
+ if (sparse_scan_file_wholesparse (file))
+ return true;
+
+ switch (hole_detection)
+ {
+ case HOLE_DETECTION_DEFAULT:
+ case HOLE_DETECTION_SEEK:
+#ifdef SEEK_HOLE
+ if (sparse_scan_file_seek (file))
+ return true;
+#else
+ if (hole_detection == HOLE_DETECTION_SEEK)
+ WARN((0, 0,
+ _("\"seek\" hole detection is not supported, using \"raw\".")));
+ /* fall back to "raw" for this and all other files */
+ hole_detection = HOLE_DETECTION_RAW;
+#endif
+ case HOLE_DETECTION_RAW:
+ if (sparse_scan_file_raw (file))
+ return true;
+ }
+
+ return false;
+}
+
static struct tar_sparse_optab const oldgnu_optab;
static struct tar_sparse_optab const star_optab;
static struct tar_sparse_optab const pax_optab;
return false;
}
set_next_block_after (blk);
- count = full_write (file->fd, blk->buffer, wrbytes);
+ count = blocking_write (file->fd, blk->buffer, wrbytes);
write_size -= count;
file->dumped_size += count;
mv_size_left (file->stat_info->archive_file_size - file->dumped_size);
/* Old GNU Format. The sparse file information is stored in the
oldgnu_header in the following manner:
- The header is marked with type 'S'. Its `size' field contains
+ The header is marked with type 'S'. Its 'size' field contains
the cumulative size of all non-empty blocks of the file. The
- actual file size is stored in `realsize' member of oldgnu_header.
+ actual file size is stored in 'realsize' member of oldgnu_header.
- The map of the file is stored in a list of `struct sparse'.
+ The map of the file is stored in a list of 'struct sparse'.
Each struct contains offset to the block of data and its
size (both as octal numbers). The first file header contains
at most 4 such structs (SPARSES_IN_OLDGNU_HEADER). If the map
- contains more structs, then the field `isextended' of the main
- header is set to 1 (binary) and the `struct sparse_header'
+ contains more structs, then the field 'isextended' of the main
+ header is set to 1 (binary) and the 'struct sparse_header'
header follows, containing at most 21 following structs
- (SPARSES_IN_SPARSE_HEADER). If more structs follow, `isextended'
+ (SPARSES_IN_SPARSE_HEADER). If more structs follow, 'isextended'
field of the extended header is set and next next extension header
follows, etc... */
return add_finish;
sp.offset = OFF_FROM_HEADER (s->offset);
sp.numbytes = OFF_FROM_HEADER (s->numbytes);
- if (sp.offset < 0
- || sp.offset + sp.numbytes < 0
+ if (sp.offset < 0 || sp.numbytes < 0
+ || INT_ADD_OVERFLOW (sp.offset, sp.numbytes)
|| file->stat_info->stat.st_size < sp.offset + sp.numbytes
|| file->stat_info->archive_file_size < 0)
return add_fail;
{
/* NOTE! st_size was initialized from the header
which actually contains archived size. The following fixes it */
+ off_t realsize = OFF_FROM_HEADER (current_header->oldgnu_header.realsize);
file->stat_info->archive_file_size = file->stat_info->stat.st_size;
- file->stat_info->stat.st_size =
- OFF_FROM_HEADER (current_header->oldgnu_header.realsize);
- return true;
+ file->stat_info->stat.st_size = max (0, realsize);
+ return 0 <= realsize;
}
/* Convert old GNU format sparse data to internal representation */
{
/* NOTE! st_size was initialized from the header
which actually contains archived size. The following fixes it */
+ off_t realsize = OFF_FROM_HEADER (current_header->star_in_header.realsize);
file->stat_info->archive_file_size = file->stat_info->stat.st_size;
- file->stat_info->stat.st_size =
- OFF_FROM_HEADER (current_header->star_in_header.realsize);
- return true;
+ file->stat_info->stat.st_size = max (0, realsize);
+ return 0 <= realsize;
}
/* Convert STAR format sparse data to internal representation */
set_next_block_after (h);
for (i = 0; i < SPARSES_IN_STAR_EXT_HEADER && rc == add_ok; i++)
rc = oldgnu_add_sparse (file, &h->star_ext_header.sp[i]);
+ file->dumped_size += BLOCKSIZE;
}
if (rc == add_fail)
|| file->stat_info->sparse_major > 0;
}
+/* Start a header that uses the effective (shrunken) file size. */
+static union block *
+pax_start_header (struct tar_stat_info *st)
+{
+ off_t realsize = st->stat.st_size;
+ union block *blk;
+ st->stat.st_size = st->archive_file_size;
+ blk = start_header (st);
+ st->stat.st_size = realsize;
+ return blk;
+}
+
static bool
pax_dump_header_0 (struct tar_sparse_file *file)
{
return false;
}
}
- blk = start_header (file->stat_info);
- /* Store the effective (shrunken) file size */
- OFF_TO_CHARS (file->stat_info->archive_file_size, blk->header.size);
+ blk = pax_start_header (file->stat_info);
finish_header (file->stat_info, blk, block_ordinal);
if (save_file_name)
{
xheader_store ("GNU.sparse.name", file->stat_info, NULL);
xheader_store ("GNU.sparse.realsize", file->stat_info, NULL);
- file->stat_info->file_name = xheader_format_name (file->stat_info,
- "%d/GNUSparseFile.%p/%f", 0);
+ file->stat_info->file_name =
+ xheader_format_name (file->stat_info, "%d/GNUSparseFile.%p/%f", 0);
+ /* Make sure the created header name is shorter than NAME_FIELD_SIZE: */
+ if (strlen (file->stat_info->file_name) > NAME_FIELD_SIZE)
+ file->stat_info->file_name[NAME_FIELD_SIZE] = 0;
- blk = start_header (file->stat_info);
- /* Store the effective (shrunken) file size */
- OFF_TO_CHARS (file->stat_info->archive_file_size, blk->header.size);
+ blk = pax_start_header (file->stat_info);
finish_header (file->stat_info, blk, block_ordinal);
free (file->stat_info->file_name);
file->stat_info->file_name = save_file_name;
if (!ISDIGIT (*arg))
return false;
+ errno = 0;
u = strtoumax (arg, &arg_lim, 10);
if (! (u <= maxval && errno != ERANGE) || *arg_lim)
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