1/*
2
3@deftypefn Supplemental char* tmpnam (char *@var{s})
4
5This function attempts to create a name for a temporary file, which
6will be a valid file name yet not exist when @code{tmpnam} checks for
7it.  @var{s} must point to a buffer of at least @code{L_tmpnam} bytes,
8or be @code{NULL}.  Use of this function creates a security risk, and it must
9not be used in new projects.  Use @code{mkstemp} instead.
10
11@end deftypefn
12
13*/
14
15#include <stdio.h>
16
17#ifndef L_tmpnam
18#define L_tmpnam 100
19#endif
20#ifndef P_tmpdir
21#define P_tmpdir "/usr/tmp"
22#endif
23
24static char tmpnam_buffer[L_tmpnam];
25static int tmpnam_counter;
26
27extern int getpid (void);
28
29char *
30tmpnam (char *s)
31{
32  int pid = getpid ();
33
34  if (s == NULL)
35    s = tmpnam_buffer;
36
37  /*  Generate the filename and make sure that there isn't one called
38      it already.  */
39
40  while (1)
41    {
42      FILE *f;
43      sprintf (s, "%s/%s%x.%x", P_tmpdir, "t", pid, tmpnam_counter);
44      f = fopen (s, "r");
45      if (f == NULL)
46	break;
47      tmpnam_counter++;
48      fclose (f);
49    }
50
51  return s;
52}
53