src/stdio/tempnam.c

   1 #include <stdio.h>
   2 #include <fcntl.h>
   3 #include <errno.h>
   4 #include <sys/stat.h>
   5 #include <limits.h>
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include "syscall.h"
   9 #include "kstat.h"
  10
  11 #define MAXTRIES 100
  12
  13 char *tempnam(const char *dir, const char *pfx)
  14 {
  15         char s[PATH_MAX];
  16         size_t l, dl, pl;
  17         int try;
  18         int r;
  19
  20         if (!dir) dir = P_tmpdir;
  21         if (!pfx) pfx = "temp";
  22
  23         dl = strlen(dir);
  24         pl = strlen(pfx);
  25         l = dl + 1 + pl + 1 + 6;
  26
  27         if (l >= PATH_MAX) {
  28                 errno = ENAMETOOLONG;
  29                 return 0;
  30         }
  31
  32         memcpy(s, dir, dl);
  33         s[dl] = '/';
  34         memcpy(s+dl+1, pfx, pl);
  35         s[dl+1+pl] = '_';
  36         s[l] = 0;
  37
  38         for (try=0; try<MAXTRIES; try++) {
  39                 __randname(s+l-6);
  40 #ifdef SYS_lstat
  41                 r = __syscall(SYS_lstat, s, &(struct kstat){0});
  42 #else
  43                 r = __syscall(SYS_fstatat, AT_FDCWD, s,
  44                         &(struct kstat){0}, AT_SYMLINK_NOFOLLOW);
  45 #endif
  46                 if (r == -ENOENT) return strdup(s);
  47         }
  48         return 0;
  49 }