--- /dev/null
+/* xsparse - expands compressed sparse file images extracted from GNU tar
+ archives.
+
+ Copyright (C) 2006 Free Software Foundation, Inc.
+
+ Written by Sergey Poznyakoff
+
+ 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
+ Free Software Foundation; either version 2, or (at your option) any later
+ version.
+
+ This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <limits.h>
+#include <errno.h>
+
+/* Bound on length of the string representing an off_t.
+ See INT_STRLEN_BOUND in intprops.h for explanation */
+#define OFF_T_STRLEN_BOUND ((sizeof (off_t) * CHAR_BIT) * 146 / 485 + 1)
+#define OFF_T_STRSIZE_BOUND (OFF_T_STRLEN_BOUND+1)
+
+#define BLOCKSIZE 512
+
+struct sp_array
+{
+ off_t offset;
+ size_t numbytes;
+};
+
+char *progname;
+int verbose;
+
+void
+die (int code, char *fmt, ...)
+{
+ va_list ap;
+
+ fprintf (stderr, "%s: ", progname);
+ va_start (ap, fmt);
+ vfprintf (stderr, fmt, ap);
+ va_end (ap);
+ fprintf (stderr, "\n");
+ exit (code);
+}
+
+void *
+emalloc (size_t size)
+{
+ char *p = malloc (size);
+ if (!p)
+ die (1, "not enough memory");
+ return p;
+}
+
+off_t
+string_to_off (char *p, char **endp)
+{
+ off_t v = 0;
+
+ for (; *p; p++)
+ {
+ int digit = *p - '0';
+ off_t x = v * 10;
+ if (9 < (unsigned) digit)
+ {
+ if (endp)
+ {
+ *endp = p;
+ break;
+ }
+ die (1, "number parse error near %s", p);
+ }
+ else if (x / 10 != v)
+ die (1, "number out of allowed range, near %s", p);
+ v = x + digit;
+ if (v < 0)
+ die (1, "negative number");
+ }
+ if (endp)
+ *endp = p;
+ return v;
+}
+
+size_t
+string_to_size (char *p, char **endp)
+{
+ off_t v = string_to_off (p, endp);
+ size_t ret = v;
+ if (ret != v)
+ die (1, "number too big");
+ return ret;
+}
+
+size_t sparse_map_size;
+struct sp_array *sparse_map;
+
+void
+get_line (char *s, int size, FILE *stream)
+{
+ char *p = fgets (s, size, stream);
+ size_t len;
+
+ if (!p)
+ die (1, "unexpected end of file");
+ len = strlen (p);
+ if (s[len - 1] != '\n')
+ die (1, "buffer overflow");
+ s[len - 1] = 0;
+}
+
+int
+get_var (FILE *fp, char **name, char **value)
+{
+ static char *buffer;
+ static size_t bufsize = OFF_T_STRSIZE_BOUND;
+ char *p, *q;
+
+ buffer = emalloc (bufsize);
+ do
+ {
+ size_t len, s;
+
+ if (!fgets (buffer, bufsize, fp))
+ return 0;
+ len = strlen (buffer);
+ if (len == 0)
+ return 0;
+
+ s = string_to_size (buffer, &p);
+ if (*p != ' ')
+ die (1, "malformed header: expected space but found %s", p);
+ if (buffer[len-1] != '\n')
+ {
+ if (bufsize < s + 1)
+ {
+ bufsize = s + 1;
+ buffer = realloc (buffer, bufsize);
+ if (!buffer)
+ die (1, "not enough memory");
+ }
+ if (!fgets (buffer + len, s - len + 1, fp))
+ die (1, "unexpected end of file or read error");
+ }
+ p++;
+ }
+ while (memcmp (p, "GNU.sparse.", 11));
+
+ p += 11;
+ q = strchr (p, '=');
+ if (!q)
+ die (1, "malformed header: expected `=' not found");
+ *q++ = 0;
+ q[strlen (q) - 1] = 0;
+ *name = p;
+ *value = q;
+ return 1;
+}
+
+char *outname;
+off_t outsize;
+unsigned version_major;
+unsigned version_minor;
+
+void
+read_xheader (char *name)
+{
+ char *kw, *val;
+ FILE *fp = fopen (name, "r");
+ char *expect = NULL;
+ size_t i = 0;
+
+ if (verbose)
+ printf ("Reading extended header file\n");
+
+ while (get_var (fp, &kw, &val))
+ {
+ if (verbose)
+ printf ("Found variable GNU.sparse.%s = %s\n", kw, val);
+
+ if (expect && strcmp (kw, expect))
+ die (1, "bad keyword sequence: expected `%s' but found `%s'",
+ expect, kw);
+ expect = NULL;
+ if (strcmp (kw, "name") == 0)
+ {
+ outname = emalloc (strlen (val) + 1);
+ strcpy (outname, val);
+ }
+ else if (strcmp (kw, "major") == 0)
+ {
+ version_major = string_to_size (val, NULL);
+ }
+ else if (strcmp (kw, "minor") == 0)
+ {
+ version_minor = string_to_size (val, NULL);
+ }
+ else if (strcmp (kw, "realsize") == 0
+ || strcmp (kw, "size") == 0)
+ {
+ outsize = string_to_off (val, NULL);
+ }
+ else if (strcmp (kw, "numblocks") == 0)
+ {
+ sparse_map_size = string_to_size (val, NULL);
+ sparse_map = emalloc (sparse_map_size * sizeof *sparse_map);
+ }
+ else if (strcmp (kw, "offset") == 0)
+ {
+ sparse_map[i].offset = string_to_off (val, NULL);
+ expect = "numbytes";
+ }
+ else if (strcmp (kw, "numbytes") == 0)
+ {
+ sparse_map[i++].numbytes = string_to_size (val, NULL);
+ }
+ else if (strcmp (kw, "map") == 0)
+ {
+ for (i = 0; i < sparse_map_size; i++)
+ {
+ sparse_map[i].offset = string_to_off (val, &val);
+ if (*val != ',')
+ die (1, "bad GNU.sparse.map: expected `,' but found `%c'",
+ *val);
+ sparse_map[i].numbytes = string_to_size (val+1, &val);
+ if (*val != ',')
+ {
+ if (!(*val == 0 && i == sparse_map_size-1))
+ die (1, "bad GNU.sparse.map: expected `,' but found `%c'",
+ *val);
+ }
+ else
+ val++;
+ }
+ if (*val)
+ die (1, "bad GNU.sparse.map: garbage at the end");
+ }
+ }
+ if (expect)
+ die (1, "bad keyword sequence: expected `%s' not found", expect);
+ if (version_major == 0 && sparse_map_size == 0)
+ die (1, "size of the sparse map unknown");
+ if (i != sparse_map_size)
+ die (1, "not all sparse entries supplied");
+ fclose (fp);
+}
+
+void
+read_map (FILE *ifp)
+{
+ size_t i;
+ char nbuf[OFF_T_STRSIZE_BOUND];
+
+ if (verbose)
+ printf ("Reading v.1.0 sparse map\n");
+
+ get_line (nbuf, sizeof nbuf, ifp);
+ sparse_map_size = string_to_size (nbuf, NULL);
+ sparse_map = emalloc (sparse_map_size * sizeof *sparse_map);
+
+ for (i = 0; i < sparse_map_size; i++)
+ {
+ get_line (nbuf, sizeof nbuf, ifp);
+ sparse_map[i].offset = string_to_off (nbuf, NULL);
+ get_line (nbuf, sizeof nbuf, ifp);
+ sparse_map[i].numbytes = string_to_size (nbuf, NULL);
+ }
+
+ fseek (ifp, ((ftell (ifp) + BLOCKSIZE - 1) / BLOCKSIZE) * BLOCKSIZE,
+ SEEK_SET);
+}
+
+void
+expand_sparse (FILE *sfp, int ofd)
+{
+ size_t i;
+ size_t maxbytes = 0;
+ char *buffer;
+
+ for (i = 0; i < sparse_map_size; i++)
+ if (maxbytes < sparse_map[i].numbytes)
+ maxbytes = sparse_map[i].numbytes;
+
+ for (buffer = malloc (maxbytes); !buffer; maxbytes /= 2)
+ if (maxbytes == 0)
+ die (1, "not enough memory");
+
+ for (i = 0; i < sparse_map_size; i++)
+ {
+ size_t size = sparse_map[i].numbytes;
+
+ lseek (ofd, sparse_map[i].offset, SEEK_SET);
+ while (size)
+ {
+ size_t rdsize = (size < maxbytes) ? size : maxbytes;
+ if (rdsize != fread (buffer, 1, rdsize, sfp))
+ die (1, "read error (%d)", errno);
+ if (rdsize != write (ofd, buffer, rdsize))
+ die (1, "write error (%d)", errno);
+ size -= rdsize;
+ }
+ }
+ free (buffer);
+}
+
+void
+usage (int code)
+{
+ printf ("Usage: %s [OPTIONS] infile [outfile]\n", progname);
+ printf ("%s: expand sparse files extracted from GNU archives\n",
+ progname);
+ printf ("\nOPTIONS are:\n\n");
+ printf (" -h Display this help list\n");
+ printf (" -n Dry run: do nothing, print what would have been done\n");
+ printf (" -v Increase verbosity level\n");
+ printf (" -x FILE Parse extended header FILE\n\n");
+
+ exit (code);
+}
+
+void
+guess_outname (char *name)
+{
+ char *p;
+ char *s;
+
+ if (name[0] == '.' && name[1] == '/')
+ name += 2;
+
+ p = name + strlen (name) - 1;
+ s = NULL;
+
+ for (; p > name && *p != '/'; p--)
+ ;
+ if (*p == '/')
+ s = p + 1;
+ if (p != name)
+ {
+ for (p--; p > name && *p != '/'; p--)
+ ;
+ }
+
+ if (*p != '/')
+ {
+ if (s)
+ outname = s;
+ else
+ {
+ outname = emalloc (4 + strlen (name));
+ strcpy (outname, "../");
+ strcpy (outname + 3, name);
+ }
+ }
+ else
+ {
+ size_t len = p - name + 1;
+ outname = emalloc (len + strlen (s) + 1);
+ memcpy (outname, name, len);
+ strcpy (outname + len, s);
+ }
+}
+
+int
+main (int argc, char **argv)
+{
+ int c;
+ int dry_run = 0;
+ char *xheader_file = NULL;
+ char *inname;
+ FILE *ifp;
+ struct stat st;
+ int ofd;
+
+ progname = argv[0];
+ while ((c = getopt (argc, argv, "hnvx:")) != EOF)
+ {
+ switch (c)
+ {
+ case 'h':
+ usage (0);
+ break;
+
+ case 'x':
+ xheader_file = optarg;
+ break;
+
+ case 'n':
+ dry_run = 1;
+ case 'v':
+ verbose++;
+ break;
+
+ default:
+ exit (1);
+ }
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if (argc == 0 || argc > 2)
+ usage (1);
+
+ if (xheader_file)
+ read_xheader (xheader_file);
+
+ inname = argv[0];
+ if (argv[1])
+ outname = argv[1];
+
+ if (stat (inname, &st))
+ die (1, "cannot stat %s (%d)", inname, errno);
+
+ ifp = fopen (inname, "r");
+ if (ifp == NULL)
+ die (1, "cannot open file %s (%d)", inname, errno);
+
+ if (!xheader_file || version_major == 1)
+ read_map (ifp);
+
+ if (!outname)
+ guess_outname (inname);
+
+ ofd = open (outname, O_RDWR|O_CREAT|O_TRUNC, st.st_mode);
+ if (ofd == -1)
+ die (1, "cannot open file %s (%d)", outname, errno);
+
+ if (verbose)
+ printf ("Expanding file `%s' to `%s'\n", inname, outname);
+
+ if (dry_run)
+ {
+ printf ("Finished dry run\n");
+ return 0;
+ }
+
+ expand_sparse (ifp, ofd);
+
+ fclose (ifp);
+ close (ofd);
+
+ if (verbose)
+ printf ("Done\n");
+
+ if (outsize)
+ {
+ if (stat (outname, &st))
+ die (1, "cannot stat output file %s (%d)", outname, errno);
+ if (st.st_size != outsize)
+ die (1, "expanded file has wrong size");
+ }
+
+ return 0;
+}
+
projects / chaz / tar / commitdiff
