mkstemps.c File Reference

#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>

Include dependency graph for mkstemps.c:

Go to the source code of this file.

Macros
#define	TMP_MAX   16384
#define	O_BINARY   0

Typedefs
typedef unsigned long	gcc_uint64_t

Functions
int	mkstemps (char *template, int suffix_len)

Macro Definition Documentation

O_BINARY

#define O_BINARY   0

Definition at line 48 of file mkstemps.c.

TMP_MAX

#define TMP_MAX   16384

Definition at line 43 of file mkstemps.c.

Typedef Documentation

gcc_uint64_t

typedef unsigned long gcc_uint64_t

Definition at line 39 of file mkstemps.c.

Function Documentation

mkstemps()

int mkstemps	(	char *	template,
		int	suffix_len
	)

Definition at line 73 of file mkstemps.c.

{
  static const char letters[]
    = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  static gcc_uint64_t value;
#ifdef HAVE_GETTIMEOFDAY
  struct timeval tv;
#endif
  char *XXXXXX;
  size_t len;
  int count;
 
  len = strlen (template);
 
  if ((int) len < 6 + suffix_len
      || strncmp (&template[len - 6 - suffix_len], "XXXXXX", 6))
    {
      printf("wrong parameter\n");
      return -1;
    }
 
  XXXXXX = &template[len - 6 - suffix_len];
 
#ifdef HAVE_GETTIMEOFDAY
  /* Get some more or less random data.  */
  gettimeofday (&tv, NULL);
  value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
#else
  value += getpid ();
#endif
 
  for (count = 0; count < TMP_MAX; ++count)
    {
      gcc_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];
 
#ifdef VMS
      fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600, "fop=tmd");
#else
      fd = open (template, O_RDWR|O_CREAT|O_EXCL|O_BINARY, 0600);
#endif
      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;
}

Referenced by chmc_section_create(), and main().