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gnupg/tools/gpgtar-extract.c
2011-01-11 19:35:05 +01:00

350 lines
8.6 KiB
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/* gpgtar-extract.c - Extract from a TAR archive
* Copyright (C) 2010 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <assert.h>
#ifdef HAVE_W32_SYSTEM
# include <fcntl.h> /* for setmode() */
#endif /*HAVE_W32_SYSTEM*/
#include "i18n.h"
#include "../common/sysutils.h"
#include "gpgtar.h"
#ifndef GPG_ERR_LIMIT_REACHED
#define GPG_ERR_LIMIT_REACHED 183
#endif
static gpg_error_t
extract_regular (estream_t stream, const char *dirname,
tar_header_t hdr)
{
gpg_error_t err;
char record[RECORDSIZE];
size_t n, nbytes, nwritten;
char *fname;
estream_t outfp = NULL;
fname = strconcat (dirname, "/", hdr->name, NULL);
if (!fname)
{
err = gpg_error_from_syserror ();
log_error ("error creating filename: %s\n", gpg_strerror (err));
goto leave;
}
else
err = 0;
outfp = es_fopen (fname, "wb");
if (!outfp)
{
err = gpg_error_from_syserror ();
log_error ("error creating `%s': %s\n", fname, gpg_strerror (err));
goto leave;
}
for (n=0; n < hdr->nrecords;)
{
err = read_record (stream, record);
if (err)
goto leave;
n++;
nbytes = (n < hdr->nrecords)? RECORDSIZE : (hdr->size % RECORDSIZE);
nwritten = es_fwrite (record, 1, nbytes, outfp);
if (nwritten != nbytes)
{
err = gpg_error_from_syserror ();
log_error ("error writing `%s': %s\n", fname, gpg_strerror (err));
goto leave;
}
}
/* Fixme: Set permissions etc. */
leave:
if (!err && opt.verbose)
log_info ("extracted `%s'\n", fname);
es_fclose (outfp);
if (err && fname && outfp)
{
if (remove (fname))
log_error ("error removing incomplete file `%s': %s\n",
fname, gpg_strerror (gpg_error_from_syserror ()));
}
xfree (fname);
return err;
}
static gpg_error_t
extract_directory (const char *dirname, tar_header_t hdr)
{
gpg_error_t err;
char *fname;
size_t prefixlen;
prefixlen = strlen (dirname) + 1;
fname = strconcat (dirname, "/", hdr->name, NULL);
if (!fname)
{
err = gpg_error_from_syserror ();
log_error ("error creating filename: %s\n", gpg_strerror (err));
goto leave;
}
else
err = 0;
if (fname[strlen (fname)-1] == '/')
fname[strlen (fname)-1] = 0;
/* Note that we don't need to care about EEXIST because we always
extract into a new hierarchy. */
if (gnupg_mkdir (fname, "-rwx------"))
{
err = gpg_error_from_syserror ();
if (gpg_err_code (err) == GPG_ERR_ENOENT)
{
/* Try to create the directory with parents but keep the
original error code in case of a failure. */
char *p;
int rc = 0;
for (p = fname+prefixlen; (p = strchr (p, '/')); p++)
{
*p = 0;
rc = gnupg_mkdir (fname, "-rwx------");
*p = '/';
if (rc)
break;
}
if (!rc && !gnupg_mkdir (fname, "-rwx------"))
err = 0;
}
if (err)
log_error ("error creating directory `%s': %s\n",
fname, gpg_strerror (err));
}
leave:
if (!err && opt.verbose)
log_info ("created `%s/'\n", fname);
xfree (fname);
return err;
}
static gpg_error_t
extract (estream_t stream, const char *dirname, tar_header_t hdr)
{
gpg_error_t err;
size_t n;
n = strlen (hdr->name);
#ifdef HAVE_DOSISH_SYSTEM
if (strchr (hdr->name, '\\'))
{
log_error ("filename `%s' contains a backslash - "
"can't extract on this system\n", hdr->name);
return gpg_error (GPG_ERR_INV_NAME);
}
#endif /*HAVE_DOSISH_SYSTEM*/
if (!n
|| strstr (hdr->name, "//")
|| strstr (hdr->name, "/../")
|| !strncmp (hdr->name, "../", 3)
|| (n >= 3 && !strcmp (hdr->name+n-3, "/.." )))
{
log_error ("filename `%s' as suspicious parts - not extracting\n",
hdr->name);
return gpg_error (GPG_ERR_INV_NAME);
}
if (hdr->typeflag == TF_REGULAR || hdr->typeflag == TF_UNKNOWN)
err = extract_regular (stream, dirname, hdr);
else if (hdr->typeflag == TF_DIRECTORY)
err = extract_directory (dirname, hdr);
else
{
char record[RECORDSIZE];
log_info ("unsupported file type %d for `%s' - skipped\n",
(int)hdr->typeflag, hdr->name);
for (err = 0, n=0; !err && n < hdr->nrecords; n++)
err = read_record (stream, record);
}
return err;
}
/* Create a new directory to be used for extracting the tarball.
Returns the name of the directory which must be freed by the
caller. In case of an error a diagnostic is printed and NULL
returned. */
static char *
create_directory (const char *dirprefix)
{
gpg_error_t err = 0;
char *prefix_buffer = NULL;
char *dirname = NULL;
size_t n;
int idx;
/* Remove common suffixes. */
n = strlen (dirprefix);
if (n > 4 && (!compare_filenames (dirprefix + n - 4, EXTSEP_S "gpg")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "pgp")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "asc")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "pem")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "p7m")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "p7e")))
{
prefix_buffer = xtrystrdup (dirprefix);
if (!prefix_buffer)
{
err = gpg_error_from_syserror ();
goto leave;
}
prefix_buffer[n-4] = 0;
dirprefix = prefix_buffer;
}
for (idx=1; idx < 5000; idx++)
{
xfree (dirname);
dirname = xtryasprintf ("%s_%d_", dirprefix, idx);
if (!dirname)
{
err = gpg_error_from_syserror ();
goto leave;
}
if (!gnupg_mkdir (dirname, "-rwx------"))
goto leave; /* Ready. */
if (errno != EEXIST && errno != ENOTDIR)
{
err = gpg_error_from_syserror ();
goto leave;
}
}
err = gpg_error (GPG_ERR_LIMIT_REACHED);
leave:
if (err)
{
log_error ("error creating an extract directory: %s\n",
gpg_strerror (err));
xfree (dirname);
dirname = NULL;
}
xfree (prefix_buffer);
return dirname;
}
void
gpgtar_extract (const char *filename)
{
gpg_error_t err;
estream_t stream;
tar_header_t header = NULL;
const char *dirprefix = NULL;
char *dirname = NULL;
if (filename)
{
if (!strcmp (filename, "-"))
stream = es_stdin;
else
stream = es_fopen (filename, "rb");
if (!stream)
{
err = gpg_error_from_syserror ();
log_error ("error opening `%s': %s\n", filename, gpg_strerror (err));
return;
}
}
else
stream = es_stdin;
#ifdef HAVE_DOSISH_SYSTEM
if (stream == es_stdin)
setmode (es_fileno (es_stdin), O_BINARY);
#endif
if (filename && stream != es_stdin)
{
dirprefix = strrchr (filename, '/');
if (dirprefix)
dirprefix++;
else
dirprefix = filename;
}
else if (opt.filename)
{
dirprefix = strrchr (opt.filename, '/');
if (dirprefix)
dirprefix++;
else
dirprefix = opt.filename;
}
if (!dirprefix || !*dirprefix)
dirprefix = "GPGARCH";
dirname = create_directory (dirprefix);
if (!dirname)
{
err = gpg_error (GPG_ERR_GENERAL);
goto leave;
}
if (opt.verbose)
log_info ("extracting to `%s/'\n", dirname);
for (;;)
{
header = gpgtar_read_header (stream);
if (!header)
goto leave;
if (extract (stream, dirname, header))
goto leave;
xfree (header);
header = NULL;
}
leave:
xfree (header);
xfree (dirname);
if (stream != es_stdin)
es_fclose (stream);
return;
}