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Implement sparse format versioning. Implement new

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version (1.0) of PAX sparse format.
(pax_sparse_member_p): Fix condition
(pax_dump_header): A dispatcher function
(pax_dump_header_0,pax_dump_header_1): New functions.
(pax_optab): Update
(oldgnu_dump_header): Minor fix: make sure
sparse_header.isextended is set before calling
set_next_block_after
This commit is contained in:
Sergey Poznyakoff
2006-06-23 15:21:48 +00:00
parent 2e1f904f2c
commit 090d1d36ae
1 changed files with 254 additions and 29 deletions
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283
src/sparse.c
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@@ -1,6 +1,6 @@
/* Functions for dealing with sparse files
Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
Copyright (C) 2003, 2004, 2005, 2006 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
@@ -740,11 +740,9 @@ oldgnu_dump_header (struct tar_sparse_file *file)
oldgnu_store_sparse_info (file, &i,
blk->sparse_header.sp,
SPARSES_IN_SPARSE_HEADER);
set_next_block_after (blk);
if (i < file->stat_info->sparse_map_avail)
blk->sparse_header.isextended = 1;
else
break;
set_next_block_after (blk);
}
return true;
}
@@ -843,16 +841,16 @@ static struct tar_sparse_optab const star_optab = {
};
/* GNU PAX sparse file format. The sparse file map is stored in
x header:
/* GNU PAX sparse file format. There are several versions:
* 0.0
The initial version of sparse format used by tar 1.14-1.15.1.
The sparse file map is stored in x header:
GNU.sparse.size Real size of the stored file
GNU.sparse.numblocks Number of blocks in the sparse map
GNU.sparse.map Map of non-null data chunks. A string consisting
of comma-separated values "offset,size[,offset,size]..."
Tar versions 1.14-1.15.1 instead of the latter used:
repeat numblocks time
GNU.sparse.offset Offset of the next data block
GNU.sparse.numbytes Size of the next data block
@@ -860,26 +858,73 @@ static struct tar_sparse_optab const star_optab = {
This has been reported as conflicting with the POSIX specs. The reason is
that offsets and sizes of non-zero data blocks were stored in multiple
instances of GNU.sparse.offset/GNU.sparse.numbytes variables. However,
instances of GNU.sparse.offset/GNU.sparse.numbytes variables, whereas
POSIX requires the latest occurrence of the variable to override all
previous occurrences.
To avoid this incompatibility new keyword GNU.sparse.map was introduced
in tar 1.15.2. Some people might still need the 1.14 way of handling
sparse files for the compatibility reasons: it can be achieved by
specifying `--pax-option delete=GNU.sparse.map' in the command line.
To avoid this incompatibility two following versions were introduced.
See FIXME-1.14-1.15.1-1.20, below.
* 0.1
Used by tar 1.15.2 -- 1.15.91 (alpha releases).
The sparse file map is stored in
x header:
GNU.sparse.size Real size of the stored file
GNU.sparse.numblocks Number of blocks in the sparse map
GNU.sparse.map Map of non-null data chunks. A string consisting
of comma-separated values "offset,size[,offset,size]..."
The resulting GNU.sparse.map string can be *very* long. While POSIX does not
impose any limit on the length of a x header variable, this can confuse some
tars.
* 1.0
Starting from this version, the exact sparse format version is specified explicitely
in the header using the following variables:
GNU.sparse.major Major version
GNU.sparse.minor Minor version
X header keeps the following variables:
GNU.sparse.name Real file name of the sparse file
GNU.sparse.realsize Real size of the stored file (corresponds to the old
GNU.sparse.size variable)
The name field of the ustar header is constructed using the pattern
"%d/GNUSparseFile.%p/%f".
The sparse map itself is stored in the file data block, preceding the actual
file data. It consists of a series of octal numbers of arbitrary length, delimited
by newlines. The map is padded with nulls to the nearest block boundary.
The first number gives the number of entries in the map. Following are map entries,
each one consisting of two numbers giving the offset and size of the
data block it describes.
The format is designed in such a way that non-posix aware tars and tars not
supporting GNU.sparse.* keywords will extract each sparse file in its condensed
form with the file map attached and will place it into a separate directory.
Then, using a simple program it would be possible to expand the file to its
original form even without GNU tar.
Bu default, v.1.0 archives are created. To use other formats, --sparse-version
option is provided. Additionally, v.0.0 can be obtained by deleting GNU.sparse.map
from 0.1 format: --sparse-version 0.1 --pax-option delete=GNU.sparse.map
*/
static bool
pax_sparse_member_p (struct tar_sparse_file *file)
{
return file->stat_info->sparse_map_avail > 0;
return file->stat_info->sparse_map_avail > 0
|| file->stat_info->sparse_major > 0;
}
static bool
pax_dump_header (struct tar_sparse_file *file)
pax_dump_header_0 (struct tar_sparse_file *file)
{
off_t block_ordinal = current_block_ordinal ();
union block *blk;
@@ -892,13 +937,8 @@ pax_dump_header (struct tar_sparse_file *file)
xheader_store ("GNU.sparse.size", file->stat_info, NULL);
xheader_store ("GNU.sparse.numblocks", file->stat_info, NULL);
/* FIXME-1.14-1.15.1-1.20: See the comment above.
Starting with 1.17 this should display a warning about POSIX-incompatible
keywords being generated. In 1.20, the true branch of the if block below
will be removed and GNU.sparse.map will be marked in xhdr_tab as
protected. */
if (xheader_keyword_deleted_p ("GNU.sparse.map"))
if (xheader_keyword_deleted_p ("GNU.sparse.map")
|| tar_sparse_minor == 0)
{
for (i = 0; i < file->stat_info->sparse_map_avail; i++)
{
@@ -936,13 +976,198 @@ pax_dump_header (struct tar_sparse_file *file)
return true;
}
static bool
pax_dump_header_1 (struct tar_sparse_file *file)
{
off_t block_ordinal = current_block_ordinal ();
union block *blk;
char *p, *q;
size_t i;
char nbuf[UINTMAX_STRSIZE_BOUND];
off_t size = 0;
struct sp_array *map = file->stat_info->sparse_map;
char *save_file_name = file->stat_info->file_name;
#define COPY_STRING(b,dst,src) do \
{ \
char *endp = b->buffer + BLOCKSIZE; \
char *srcp = src; \
while (*srcp) \
{ \
if (dst == endp) \
{ \
set_next_block_after (b); \
b = find_next_block (); \
dst = b->buffer; \
endp = b->buffer + BLOCKSIZE; \
} \
*dst++ = *srcp++; \
} \
} while (0)
/* Compute stored file size */
p = umaxtostr (file->stat_info->sparse_map_avail, nbuf);
size += strlen (p) + 1;
for (i = 0; i < file->stat_info->sparse_map_avail; i++)
{
p = umaxtostr (map[i].offset, nbuf);
size += strlen (p) + 1;
p = umaxtostr (map[i].numbytes, nbuf);
size += strlen (p) + 1;
}
size = (size + BLOCKSIZE - 1) / BLOCKSIZE;
file->stat_info->archive_file_size += size * BLOCKSIZE;
/* Store sparse file identification */
xheader_store ("GNU.sparse.major", file->stat_info, NULL);
xheader_store ("GNU.sparse.minor", file->stat_info, NULL);
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);
blk = start_header (file->stat_info);
/* Store the effective (shrunken) file size */
OFF_TO_CHARS (file->stat_info->archive_file_size, blk->header.size);
finish_header (file->stat_info, blk, block_ordinal);
free (file->stat_info->file_name);
file->stat_info->file_name = save_file_name;
blk = find_next_block ();
q = blk->buffer;
p = umaxtostr (file->stat_info->sparse_map_avail, nbuf);
COPY_STRING (blk, q, p);
COPY_STRING (blk, q, "\n");
for (i = 0; i < file->stat_info->sparse_map_avail; i++)
{
p = umaxtostr (map[i].offset, nbuf);
COPY_STRING (blk, q, p);
COPY_STRING (blk, q, "\n");
p = umaxtostr (map[i].numbytes, nbuf);
COPY_STRING (blk, q, p);
COPY_STRING (blk, q, "\n");
}
memset (q, 0, BLOCKSIZE - (q - blk->buffer));
set_next_block_after (blk);
return true;
}
static bool
pax_dump_header (struct tar_sparse_file *file)
{
file->stat_info->sparse_major = tar_sparse_major;
file->stat_info->sparse_minor = tar_sparse_minor;
if (file->stat_info->sparse_major == 0)
pax_dump_header_0 (file);
else
pax_dump_header_1 (file);
}
static bool
decode_num (uintmax_t *num, char const *arg, uintmax_t maxval)
{
uintmax_t u;
char *arg_lim;
if (!ISDIGIT (*arg))
return false;
u = strtoumax (arg, &arg_lim, 10);
if (! (u <= maxval && errno != ERANGE) || *arg_lim)
return false;
*num = u;
return true;
}
static bool
pax_decode_header (struct tar_sparse_file *file)
{
if (file->stat_info->sparse_major > 0)
{
uintmax_t u;
char nbuf[UINTMAX_STRSIZE_BOUND];
union block *blk;
char *p;
size_t i;
#define COPY_BUF(b,buf,src) do \
{ \
char *endp = b->buffer + BLOCKSIZE; \
char *dst = buf; \
do \
{ \
if (dst == buf + UINTMAX_STRSIZE_BOUND -1) \
{ \
ERROR ((0, 0, _("%s: numeric overflow in sparse archive member"), \
file->stat_info->orig_file_name)); \
return false; \
} \
if (src == endp) \
{ \
set_next_block_after (b); \
b = find_next_block (); \
src = b->buffer; \
endp = b->buffer + BLOCKSIZE; \
} \
*dst = *src++; \
} \
while (*dst++ != '\n'); \
dst[-1] = 0; \
} while (0)
set_next_block_after (current_header);
blk = find_next_block ();
p = blk->buffer;
COPY_BUF (blk,nbuf,p);
if (!decode_num (&u, nbuf, TYPE_MAXIMUM (size_t)))
{
ERROR ((0, 0, _("%s: malformed sparse archive member"),
file->stat_info->orig_file_name));
return false;
}
file->stat_info->sparse_map_size = u;
file->stat_info->sparse_map = xcalloc (file->stat_info->sparse_map_size,
sizeof (*file->stat_info->sparse_map));
file->stat_info->sparse_map_avail = 0;
for (i = 0; i < file->stat_info->sparse_map_size; i++)
{
struct sp_array sp;
COPY_BUF (blk,nbuf,p);
if (!decode_num (&u, nbuf, TYPE_MAXIMUM (off_t)))
{
ERROR ((0, 0, _("%s: malformed sparse archive member"),
file->stat_info->orig_file_name));
return false;
}
sp.offset = u;
COPY_BUF (blk,nbuf,p);
if (!decode_num (&u, nbuf, TYPE_MAXIMUM (size_t)))
{
ERROR ((0, 0, _("%s: malformed sparse archive member"),
file->stat_info->orig_file_name));
return false;
}
sp.numbytes = u;
sparse_add_map (file->stat_info, &sp);
}
set_next_block_after (blk);
}
return true;
}
static struct tar_sparse_optab const pax_optab = {
NULL, /* No init function */
NULL, /* No done function */
pax_sparse_member_p,
pax_dump_header,
NULL, /* No decode_header function */
NULL, /* No fixup_header function */
NULL,
pax_decode_header,
NULL, /* No scan_block function */
sparse_dump_region,
sparse_extract_region,