Add mktemp() and mkstemp()

4 files changed, 385 insertions, 1 deletions

diff --git a/nuttx/include/stdlib.h b/nuttx/include/stdlib.h
index 127b35163..c149e0ac1 100644
--- a/nuttx/include/stdlib.h
+++ b/nuttx/include/stdlib.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/stdlib.h
  *
- *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -182,6 +182,8 @@ long int labs(long int j);
 #ifdef CONFIG_HAVE_LONG_LONG
 long long int llabs(long long int j);
 #endif
+int      mktemp(FAR char *template);
+int      mkstemp(FAR char *template);
 
 /* Sorting */
 
diff --git a/nuttx/libc/stdlib/Make.defs b/nuttx/libc/stdlib/Make.defs
index 5501ef0c1..6a0d8ad7d 100644
--- a/nuttx/libc/stdlib/Make.defs
+++ b/nuttx/libc/stdlib/Make.defs
@@ -40,6 +40,10 @@ CSRCS += lib_llabs.c lib_rand.c lib_qsort.c
 CSRCS += lib_strtol.c lib_strtoll.c lib_strtoul.c lib_strtoull.c
 CSRCS += lib_strtod.c lib_checkbase.c
 
+ifeq ($(CONFIG_FS_WRITABLE),y)
+CSRCS += lib_mktemp.c lib_mkstemp.c
+endif
+
 # Add the stdlib directory to the build
 
 DEPPATH += --dep-path stdlib
diff --git a/nuttx/libc/stdlib/lib_mkstemp.c b/nuttx/libc/stdlib/lib_mkstemp.c
new file mode 100644
index 000000000..3269463f5
--- /dev/null
+++ b/nuttx/libc/stdlib/lib_mkstemp.c
@@ -0,0 +1,297 @@
+/****************************************************************************
+ * libc/stdlib/lib_mkstemp.c
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <stdint.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <semaphore.h>
+#include <errno.h>
+
+#ifdef CONFIG_FS_WRITABLE
+
+/****************************************************************************
+ * Pre-processor definitions
+ ****************************************************************************/
+
+ #ifndef CONFIG_LIBC_TMPDIR
+#  define CONFIG_LIBC_TMPDIR "/tmp"
+#endif
+
+#define MAX_XS        6
+#define MIN_NUMERIC   0    /* 0-9:   Numeric */
+#define MAX_NUMERIC   9
+#define MIN_UPPERCASE 10   /* 10-35: Upper case */ 
+#define MAX_UPPERCASE 35
+#define MIN_LOWERCASE 36   /* 36-61: Lower case */
+#define MAX_LOWERCASE 61
+#define MAX_BASE62    MAX_LOWERCASE
+
+/* 62**1 = 62
+ * 62**2 = 3844
+ * 62**3 = 238328
+ * 62**4 = 14776336
+ * 62**5 = 916132832
+ * 62**6 = 56800235584 > UINT32_MAX
+ */
+
+#define BIG_XS 5
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static uint8_t g_base62[MAX_XS];
+static sem_t g_b62sem = SEM_INITIALIZER(1);
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: base62_to_char
+ *
+ * Description:
+ *   Convert a base62 value to a printable character.
+ *
+ ****************************************************************************/
+
+static char base62_to_char(uint8_t base62)
+{
+  if (base62 <= MAX_NUMERIC)
+    {
+      return '0' + base62;
+    }
+  else if (base62 <= MAX_UPPERCASE)
+    {
+      return 'A' + base62 - MIN_UPPERCASE;
+    }
+  else /* if (base62 <= MAX_LOWERCASE) */
+    {
+      DEBUGASSERT(base62 <= MAX_LOWERCASE);
+      return 'a' + base62 - MIN_LOWERCASE;
+    }
+}
+
+/****************************************************************************
+ * Name: incr_base62
+ *
+ * Description:
+ *   increment the base62 value array.
+ *
+ ****************************************************************************/
+
+static void incr_base62(void)
+{
+  int i;
+
+  for (i = 0; i < MAX_XS; i++)
+    {
+      if (g_base62[i] < MAX_LOWERCASE)
+        {
+          g_base62[i]++;
+          return;
+        }
+      else
+        {
+          g_base62[i] = 0;
+        }
+    }
+}
+
+/****************************************************************************
+ * Name: get_base62
+ *
+ * Description:
+ *   Atomically copy and increment the base62 array.
+ *
+ ****************************************************************************/
+
+static void get_base62(FAR uint8_t *ptr)
+{
+  int ret;
+
+  while ((ret = sem_wait(&g_b62sem)) < 0)
+    {
+      DEBUGASSERT(errno == EINTR);
+    }
+     
+  memcpy(ptr, g_base62, MAX_XS);
+  incr_base62();
+  sem_post(&g_b62sem);
+}
+
+/****************************************************************************
+ * Name: copy_base62
+ *
+ * Description:
+ *   Copy the base62 array into the template filename, converting each
+ *   base62 value to a printable character.
+ *
+ ****************************************************************************/
+
+static void copy_base62(FAR char *dest, int len)
+{
+  FAR const uint8_t *src;
+
+  src = g_base62;
+  if (len < MAX_XS)
+     {
+       src += MAX_XS - len;
+     }
+
+   for (; len > 0; len--)
+     {
+       *dest++ = base62_to_char(*src++);
+     }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: mkstemp
+ *
+ * Description:
+ *   The mkstemp() function replaces the contents of the string pointed to
+ *   by template by a unique filename, and returns a file descriptor for the
+ *   file open for reading and writing. The function thus prevents any
+ *   possible race condition between testing whether the file exists and
+ *   opening it for use. The string in template should look like a filename
+ *   with six trailing 'X' s; mkstemp() replaces each 'X' with a character
+ *   from the portable filename character set. The characters are chosen
+ *   such that the resulting name does not duplicate the name of an existing
+ *   file at the time of a call to mkstemp().
+ *
+ * Input Parameters:
+ *   template - The base file name that will be modified to produce the
+ *     unique file name.  This must be a full path beginning with /tmp.
+ *     This function will modify only the first XXXXXX characters within
+ *     that full path.
+ *
+ * Returned Value:
+ *
+ * Upon successful completion, mkstemp() returns an open file descriptor.
+ * Otherwise, -1 is returned if no suitable file could be created.
+ *
+ ****************************************************************************/
+
+int mkstemp(FAR char *template)
+{
+  uint8_t base62[MAX_XS];
+  uint32_t retries;
+  FAR char *xptr;
+  FAR char *ptr;
+  int xlen;
+  int fd;
+  int i;
+
+  /* Count the number of X's at the end of the template */
+
+  xptr = strchr(template, 'X');
+  if (!xptr)
+    {
+      /* No Xs?  There should always really be 6 */
+
+      return open(template, O_RDWR | O_CREAT | O_EXCL, 0666);
+    }
+
+  /* There is at least one.. count all of them */
+
+  for (xlen = 0, ptr = xptr; xlen < MAX_XS && *ptr == 'X'; xlen++, ptr++);
+
+  /* Ignore any X's after the sixth */
+
+  if (xlen > MAX_XS)
+    {
+      xlen = MAX_XS;
+    }
+
+  /* If xlen is small, then we need to determine the maximum number of
+   * retries before the values will repeat.
+   */
+
+  if (xlen >= BIG_XS)
+    {
+      retries = UINT32_MAX;
+    }
+  else
+    {
+      for (i = 1, retries = 62; i < xlen; i++, retries *= 62);
+    }
+
+  /* Then loop until we find a unique file name */
+
+  while (retries > 0)
+    {
+      /* Sample and increment the base62 counter */
+
+       get_base62(base62);
+
+      /* Form the candidate file name */
+
+      copy_base62(xptr, xlen);
+
+      /* Attempt to open the candidate file -- creating it exclusively
+       *
+       * REVISIT: This prohibits the use of this function to create unique
+       * directories
+       */
+
+      fd = open(template, O_RDWR | O_CREAT | O_EXCL, 0666);
+      if (fd >= 0)
+        {
+          /* We have it... return the file descriptor */
+
+          return fd;
+        }
+    }
+
+  /* We could not find an unique filename */
+
+  return ERROR;
+}
+
+#endif /* CONFIG_FS_WRITABLE */
+
diff --git a/nuttx/libc/stdlib/lib_mktemp.c b/nuttx/libc/stdlib/lib_mktemp.c
new file mode 100644
index 000000000..705c5cb9e
--- /dev/null
+++ b/nuttx/libc/stdlib/lib_mktemp.c
@@ -0,0 +1,81 @@
+/****************************************************************************
+ * libc/stdlib/lib_mktemp.c
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <unistd.h>
+#include <stdlib.h>
+
+#ifdef CONFIG_FS_WRITABLE
+
+/****************************************************************************
+ * Pre-processor definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: mktemp
+ *
+ * Description:
+ *   The use of mktemp is dangerous; use mkstemp instead.
+ *
+ ****************************************************************************/
+
+int mktemp(FAR char *template)
+{
+  int fd = mkstemp(template);
+  if (fd < 0)
+    {
+      return ERROR;
+    }
+
+  close(fd);
+  return OK;
+}
+
+#endif /* CONFIG_FS_WRITABLE */
+