Commit e443729d authored by Eli Zaretskii's avatar Eli Zaretskii

MS-Windows followup to last commit.

 lib-src/ntlib.h: Include fcntl.h.
 (mkostemp): Declare prototype.
 (mktemp): Don't redefine.
 lib-src/ntlib.c (mkostemp): New function.

Fixes: debbugs:15015
parent e0fdb694
2013-08-04 Eli Zaretskii <eliz@gnu.org>
* ntlib.h: Include fcntl.h.
(mkostemp): Declare prototype.
(mktemp): Don't redefine.
* ntlib.c (mkostemp): New function. (Bug#15015)
2013-08-04 Paul Eggert <eggert@cs.ucla.edu>
Fix some minor races in hosts lacking mkostemp (Bug#15015).
......
......@@ -422,3 +422,58 @@ lstat (const char * path, struct stat * buf)
{
return stat (path, buf);
}
/* Implementation of mkostemp for MS-Windows, to avoid race conditions
when using mktemp.
Standard algorithm for generating a temporary file name seems to be
use pid or tid with a letter on the front (in place of the 6 X's)
and cycle through the letters to find a unique name. We extend
that to allow any reasonable character as the first of the 6 X's,
so that the number of simultaneously used temporary files will be
greater. */
int
mkostemp (char * template, int flags)
{
char * p;
int i, fd = -1;
unsigned uid = GetCurrentThreadId ();
int save_errno = errno;
static char first_char[] = "abcdefghijklmnopqrstuvwyz0123456789!%-_@#";
errno = EINVAL;
if (template == NULL)
return -1;
p = template + strlen (template);
i = 5;
/* replace up to the last 5 X's with uid in decimal */
while (--p >= template && p[0] == 'X' && --i >= 0)
{
p[0] = '0' + uid % 10;
uid /= 10;
}
if (i < 0 && p[0] == 'X')
{
i = 0;
do
{
p[0] = first_char[i];
if ((fd = open (template,
flags | _O_CREAT | _O_EXCL | _O_RDWR,
S_IRUSR | S_IWUSR)) >= 0
|| errno != EEXIST)
{
if (fd >= 0)
errno = save_errno;
return fd;
}
}
while (++i < sizeof (first_char));
}
/* Template is badly formed or else we can't generate a unique name. */
return -1;
}
......@@ -22,6 +22,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
/* Include these headers now so we don't have to worry about include
order dependencies in common source files. */
#include <direct.h>
#include <fcntl.h>
#include <io.h>
#include <stdio.h>
......@@ -41,6 +42,7 @@ int setuid (unsigned uid);
int setregid (unsigned rgid, unsigned gid);
char * getpass (const char * prompt);
int fchown (int fd, unsigned uid, unsigned gid);
int mkostemp (char * template, int flags);
/* redirect or undo interceptions created by config.h */
#undef access
......@@ -61,8 +63,6 @@ int fchown (int fd, unsigned uid, unsigned gid);
#undef fopen
#undef mkdir
#define mkdir _mkdir
#undef mktemp
#define mktemp _mktemp
#undef open
#define open _open
#undef pipe
......
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