glibc/stdio-common/tmpnam.c
Adhemerval Zanella 686d542025 posix: Sync tempname with gnulib
The gnulib version contains an important change (9ce573cde), which
fixes some problems with multithreading, entropy loss, and ASLR leak
nfo.  It also fixes an issue where getrandom is not being used
on some new files generation (only for __GT_NOCREATE on first try).

The 044bf893ac removed __path_search, which is now moved to another
gnulib shared files (stdio-common/tmpdir.{c,h}).  Tthis patch
also fixes direxists to use __stat64_time64 instead of __xstat64,
and move the include of pathmax.h for !_LIBC (since it is not used
by glibc).  The license is also changed from GPL 3.0 to 2.1, with
permission from the authors (Bruno Haible and Paul Eggert).

The sync also removed the clock fallback, since clock_gettime
with CLOCK_REALTIME is expected to always succeed.

It syncs with gnulib commit 323834962817af7b115187e8c9a833437f8d20ec.

Checked on x86_64-linux-gnu.

Co-authored-by: Bruno Haible <bruno@clisp.org>
Co-authored-by: Paul Eggert <eggert@cs.ucla.edu>
Reviewed-by: Bruno Haible <bruno@clisp.org>
2024-04-10 14:53:39 -03:00

53 lines
1.7 KiB
C

/* Copyright (C) 1991-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <string.h>
#include "tmpdir.h"
static char tmpnam_buffer[L_tmpnam];
/* Generate a unique filename in P_tmpdir.
This function is *not* thread safe! */
char *
tmpnam (char s[L_tmpnam])
{
/* By using two buffers we manage to be thread safe in the case
where S != NULL. */
char tmpbufmem[L_tmpnam];
char *tmpbuf = s ?: tmpbufmem;
/* In the following call we use the buffer pointed to by S if
non-NULL although we don't know the size. But we limit the size
to L_tmpnam characters in any case. */
if (__builtin_expect (__path_search (tmpbuf, L_tmpnam, NULL, NULL, 0),
0))
return NULL;
if (__glibc_unlikely (__gen_tempname (tmpbuf, 0, 0, __GT_NOCREATE)))
return NULL;
if (s == NULL)
return (char *) memcpy (tmpnam_buffer, tmpbuf, L_tmpnam);
return s;
}
link_warning (tmpnam,
"the use of `tmpnam' is dangerous, better use `mkstemp'")