mirror of
git://git.gnupg.org/gnupg.git
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219 lines
5.5 KiB
C
219 lines
5.5 KiB
C
/* Copyright (C) 1999, 2001-2003, 2006 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, see <http://www.gnu.org/licenses/>. */
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/* Extracted from misc/mkdtemp.c and sysdeps/posix/tempname.c. */
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#include <config.h>
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/* Specification. */
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#include "mkdtemp.h"
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#include <errno.h>
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#ifndef __set_errno
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# ifdef HAVE_W32CE_SYSTEM
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# include <gpg-error.h>
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# define __set_errno(Val) gpg_err_set_errno ((Val))
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# else
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# define __set_errno(Val) errno = (Val)
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# endif
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#endif
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#ifndef TMP_MAX
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# define TMP_MAX 238328
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#endif
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#include <unistd.h>
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#if HAVE_GETTIMEOFDAY || _LIBC
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# if HAVE_SYS_TIME_H || _LIBC
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# include <sys/time.h>
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# endif
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#else
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# if HAVE_TIME_H || _LIBC
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# include <time.h>
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# endif
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#endif
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#include <sys/stat.h>
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#if !defined S_ISDIR && defined S_IFDIR
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# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
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#endif
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#if !S_IRUSR && S_IREAD
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# define S_IRUSR S_IREAD
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#endif
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#if !S_IRUSR
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# define S_IRUSR 00400
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#endif
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#if !S_IWUSR && S_IWRITE
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# define S_IWUSR S_IWRITE
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#endif
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#if !S_IWUSR
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# define S_IWUSR 00200
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#endif
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#if !S_IXUSR && S_IEXEC
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# define S_IXUSR S_IEXEC
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#endif
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#if !S_IXUSR
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# define S_IXUSR 00100
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#endif
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#ifdef __MINGW32__
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# include <io.h>
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#endif
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#ifdef HAVE_W32CE_SYSTEM
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#include <windows.h>
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#define getpid() GetCurrentProcessId ()
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#endif
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#if !_LIBC
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# define __getpid getpid
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# define __gettimeofday gettimeofday
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# define __mkdir mkdir
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#endif
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/* Use the widest available unsigned type if uint64_t is not
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available. The algorithm below extracts a number less than 62**6
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(approximately 2**35.725) from uint64_t, so ancient hosts where
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uintmax_t is only 32 bits lose about 3.725 bits of randomness,
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which is better than not having mkstemp at all. */
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#if !defined UINT64_MAX && !defined uint64_t
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# define uint64_t uintmax_t
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#endif
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/* These are the characters used in temporary filenames. */
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static const char letters[] =
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"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
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/* Generate a temporary file name based on TMPL. TMPL must match the
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rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed
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does not exist at the time of the call to __gen_tempname. TMPL is
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overwritten with the result.
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KIND is:
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__GT_DIR: create a directory, which will be mode 0700.
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We use a clever algorithm to get hard-to-predict names. */
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static int
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gen_tempname (char *tmpl)
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{
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int len;
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char *XXXXXX;
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static uint64_t value;
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uint64_t random_time_bits;
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unsigned int count;
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int fd = -1;
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int save_errno = errno;
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/* A lower bound on the number of temporary files to attempt to
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generate. The maximum total number of temporary file names that
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can exist for a given template is 62**6. It should never be
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necessary to try all these combinations. Instead if a reasonable
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number of names is tried (we define reasonable as 62**3) fail to
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give the system administrator the chance to remove the problems. */
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#define ATTEMPTS_MIN (62 * 62 * 62)
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/* The number of times to attempt to generate a temporary file. To
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conform to POSIX, this must be no smaller than TMP_MAX. */
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#if ATTEMPTS_MIN < TMP_MAX
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unsigned int attempts = TMP_MAX;
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#else
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unsigned int attempts = ATTEMPTS_MIN;
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#endif
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len = strlen (tmpl);
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if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
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{
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__set_errno (EINVAL);
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return -1;
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}
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/* This is where the Xs start. */
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XXXXXX = &tmpl[len - 6];
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/* Get some more or less random data. */
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#ifdef RANDOM_BITS
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RANDOM_BITS (random_time_bits);
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#else
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# if HAVE_GETTIMEOFDAY || _LIBC
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{
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struct timeval tv;
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__gettimeofday (&tv, NULL);
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random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
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}
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# else
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random_time_bits = time (NULL);
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# endif
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#endif
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value += random_time_bits ^ __getpid ();
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for (count = 0; count < attempts; value += 7777, ++count)
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{
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uint64_t v = value;
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/* Fill in the random bits. */
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XXXXXX[0] = letters[v % 62];
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v /= 62;
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XXXXXX[1] = letters[v % 62];
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v /= 62;
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XXXXXX[2] = letters[v % 62];
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v /= 62;
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XXXXXX[3] = letters[v % 62];
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v /= 62;
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XXXXXX[4] = letters[v % 62];
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v /= 62;
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XXXXXX[5] = letters[v % 62];
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#ifdef MKDIR_TAKES_ONE_ARG
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fd = mkdir (tmpl);
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#else
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fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
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#endif
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if (fd >= 0)
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{
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__set_errno (save_errno);
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return fd;
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}
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else if (errno != EEXIST)
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return -1;
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}
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/* We got out of the loop because we ran out of combinations to try. */
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__set_errno (EEXIST);
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return -1;
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}
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/* Generate a unique temporary directory from TEMPLATE.
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The last six characters of TEMPLATE must be "XXXXXX";
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they are replaced with a string that makes the filename unique.
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The directory is created, mode 700, and its name is returned.
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(This function comes from OpenBSD.) */
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char *
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mkdtemp (char *template)
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{
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if (gen_tempname (template))
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return NULL;
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else
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return template;
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}
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