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gnupg/g10/mkdtemp.c
Werner Koch c0c2c58054 Finished the bulk of changes for gnupg 1.9. This included switching
to libgcrypt functions, using shared error codes from libgpg-error,
replacing the old functions we used to have in ../util by those in
../jnlib and ../common, renaming the malloc functions and a couple of
types.  Note, that not all changes are listed below becuause they are
too similar and done at far too many places.  As of today the code
builds using the current libgcrypt from CVS but it is very unlikely
that it actually works.
2003-06-18 19:56:13 +00:00

99 lines
2.4 KiB
C

/* mkdtemp.c - libc replacement function
* Copyright (C) 2001 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
/* This is a replacement function for mkdtemp in case the platform
we're building on (like mine!) doesn't have it. */
#include <config.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include "types.h"
#include "cipher.h"
#ifdef MKDIR_TAKES_ONE_ARG
# undef mkdir
# define mkdir(a,b) mkdir(a)
#endif
char *mkdtemp(char *template)
{
unsigned int attempts,idx,count=0;
byte *ch;
idx=strlen(template);
/* Walk backwards to count all the Xes */
while(idx>0 && template[idx-1]=='X')
{
count++;
idx--;
}
if(count==0)
{
errno=EINVAL;
return NULL;
}
ch=&template[idx];
/* Try 4 times to make the temp directory */
for(attempts=0;attempts<4;attempts++)
{
unsigned int remaining=count;
char *marker=ch;
byte *randombits;
idx=0;
/* Using really random bits is probably overkill here. The
worst thing that can happen with a directory name collision
is that the function will return an error. */
randombits=get_random_bits(4*remaining,0,0);
while(remaining>1)
{
sprintf(marker,"%02X",randombits[idx++]);
marker+=2;
remaining-=2;
}
/* Any leftover Xes? get_random_bits rounds up to full bytes,
so this is safe. */
if(remaining>0)
sprintf(marker,"%X",randombits[idx]&0xF);
xfree (randombits);
if(mkdir(template,0700)==0)
break;
}
if(attempts==4)
return NULL; /* keeps the errno from mkdir, whatever it is */
return template;
}