summaryrefslogtreecommitdiff
path: root/gcc/mkstemp.c
diff options
context:
space:
mode:
Diffstat (limited to 'gcc/mkstemp.c')
-rw-r--r--gcc/mkstemp.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/gcc/mkstemp.c b/gcc/mkstemp.c
new file mode 100644
index 00000000000..1ef90a5c708
--- /dev/null
+++ b/gcc/mkstemp.c
@@ -0,0 +1,111 @@
+/* Copyright (C) 1991, 1992, 1996, 1998 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#ifndef IN_GCC
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+#else
+#include "config.h"
+#include "system.h"
+
+/* We need to provide a type for uint64_t. */
+#ifdef __GNUC__
+typedef unsigned long long uint64_t;
+#else
+typedef unsigned long uint64_t;
+#endif
+
+#ifndef TMP_MAX
+#define TMP_MAX 16384
+#endif
+#endif
+
+/* Generate a unique temporary file name from TEMPLATE.
+ The last six characters of TEMPLATE must be "XXXXXX";
+ they are replaced with a string that makes the filename unique.
+ Returns a file descriptor open on the file for reading and writing. */
+int
+mkstemp (template)
+ char *template;
+{
+ static const char letters[62]
+ = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+ static uint64_t value;
+#ifdef HAVE_GETTIMEOFDAY
+ struct timeval tv;
+#endif
+ char *XXXXXX;
+ size_t len;
+ int count;
+
+ len = strlen (template);
+ if (len < 6 || strcmp (&template[len - 6], "XXXXXX"))
+ {
+ return -1;
+ }
+
+ /* This is where the Xs start. */
+ XXXXXX = &template[len - 6];
+
+#ifdef HAVE_GETTIMEOFDAY
+ /* Get some more or less random data. */
+ __gettimeofday (&tv, NULL);
+ value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
+#else
+ value += getpid ();
+#endif
+
+ for (count = 0; count < TMP_MAX; ++count)
+ {
+ uint64_t v = value;
+ int fd;
+
+ /* Fill in the random bits. */
+ XXXXXX[0] = letters[v % 62];
+ v /= 62;
+ XXXXXX[1] = letters[v % 62];
+ v /= 62;
+ XXXXXX[2] = letters[v % 62];
+ v /= 62;
+ XXXXXX[3] = letters[v % 62];
+ v /= 62;
+ XXXXXX[4] = letters[v % 62];
+ v /= 62;
+ XXXXXX[5] = letters[v % 62];
+
+ fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600);
+ if (fd >= 0)
+ /* The file does not exist. */
+ return fd;
+
+ /* This is a random value. It is only necessary that the next
+ TMP_MAX values generated by adding 7777 to VALUE are different
+ with (module 2^32). */
+ value += 7777;
+ }
+
+ /* We return the null string if we can't find a unique file name. */
+ template[0] = '\0';
+ return -1;
+}