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-rw-r--r--contrib/stdlib/gf_mkostemp.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/contrib/stdlib/gf_mkostemp.c b/contrib/stdlib/gf_mkostemp.c
new file mode 100644
index 0000000..988300a
--- /dev/null
+++ b/contrib/stdlib/gf_mkostemp.c
@@ -0,0 +1,110 @@
+/* Borrowed from glibc-2.16/sysdeps/posix/tempname.c */
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <time.h>
+#include <inttypes.h>
+
+/* Copyright (C) 1991-2001, 2006, 2007, 2009 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
+ <http://www.gnu.org/licenses/>. */
+
+static const char letters[] =
+"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+
+/* Generate a temporary file name based on TMPL. TMPL must match the
+ rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
+*/
+
+int
+gf_mkostemp (char *tmpl, int suffixlen, int flags)
+{
+ int len;
+ char *XXXXXX;
+ static uint64_t value;
+ uint64_t random_time_bits;
+ unsigned int count;
+ int fd = -1;
+
+ /* A lower bound on the number of temporary files to attempt to
+ generate. The maximum total number of temporary file names that
+ can exist for a given template is 62**6. It should never be
+ necessary to try all these combinations. Instead if a reasonable
+ number of names is tried (we define reasonable as 62**3) fail to
+ give the system administrator the chance to remove the problems. */
+#define ATTEMPTS_MIN (62 * 62 * 62)
+
+ /* The number of times to attempt to generate a temporary file. To
+ conform to POSIX, this must be no smaller than TMP_MAX. */
+#if ATTEMPTS_MIN < TMP_MAX
+ unsigned int attempts = TMP_MAX;
+#else
+ unsigned int attempts = ATTEMPTS_MIN;
+#endif
+
+ len = strlen (tmpl);
+ if (len < 6 + suffixlen || memcmp (&tmpl[len - 6 - suffixlen],
+ "XXXXXX", 6))
+ return -1;
+
+ /* This is where the Xs start. */
+ XXXXXX = &tmpl[len - 6 - suffixlen];
+
+ /* Get some more or less random data. */
+# if HAVE_GETTIMEOFDAY
+ struct timeval tv;
+ gettimeofday (&tv, NULL);
+ random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
+# else
+ random_time_bits = time (NULL);
+# endif
+
+ value += random_time_bits ^ getpid ();
+
+ for (count = 0; count < attempts; value += 7777, ++count) {
+ uint64_t v = value;
+
+ /* 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 (tmpl, (flags & ~O_ACCMODE)
+ | O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+
+ if (fd >= 0)
+ return fd;
+ else if (errno != EEXIST)
+ return -1;
+ }
+
+ /* We got out of the loop because we ran out of combinations to try. */
+ return -1;
+}