glusterfs: add gf_mkostemp api and use it instead of mkostemp of libc

Change-Id: Icc12b99e2233d22037e2c4bb2b6966e45668b7dd
BUG: 764890
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>
Reviewed-on: http://review.gluster.org/4091
Reviewed-by: Anand Avati <avati@redhat.com>
Tested-by: Anand Avati <avati@redhat.com>

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 00000000000..988300adb1c
--- /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;
+}