104 lines
2.5 KiB
C
104 lines
2.5 KiB
C
/* mkdtemp.c - libc replacement function
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* Copyright (C) 2001 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG 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 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG 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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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/* This is a replacement function for mkdtemp in case the platform
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we're building on (like mine!) doesn't have it. */
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <opensc/scrandom.h>
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#ifdef MKDIR_TAKES_ONE_ARG
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# undef mkdir
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# define mkdir(a,b) mkdir(a)
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#endif
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char *mkdtemp(char *tmpl)
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{
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int attempts, idx, count = 0;
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char *ch;
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idx = strlen(tmpl);
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/* Walk backwards to count all the Xes */
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while (idx > 0 && tmpl[idx - 1] == 'X') {
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count++;
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idx--;
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}
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if (count == 0) {
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errno = EINVAL;
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return NULL;
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}
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ch = &tmpl[idx];
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/* Try 4 times to make the temp directory */
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for (attempts = 0; attempts < 4; attempts++) {
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int remaining = count;
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char *marker = ch;
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unsigned char *randombits;
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idx = 0;
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/* Using really random bits is probably overkill here. The
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worst thing that can happen with a directory name collision
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is that the function will return an error. */
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randombits = (unsigned char *) malloc(4 * remaining);
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assert(randombits != NULL);
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assert(scrandom_get_data(randombits, 4 * remaining) ==
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4 * remaining);
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while (remaining > 1) {
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sprintf(marker, "%02X", randombits[idx++]);
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marker += 2;
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remaining -= 2;
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}
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/* Any leftover Xes? get_random_bits rounds up to full bytes,
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so this is safe. */
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if (remaining > 0)
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sprintf(marker, "%X", randombits[idx] & 0xF);
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free(randombits);
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if (mkdir(tmpl, 0700) == 0)
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break;
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}
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if (attempts == 4)
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return NULL; /* keeps the errno from mkdir, whatever it is */
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return tmpl;
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}
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