1 /* 2 3 @deftypefn Supplemental char* tmpnam (char *@var{s}) 4 5 This function attempts to create a name for a temporary file, which 6 will be a valid file name yet not exist when @code{tmpnam} checks for 7 it. @var{s} must point to a buffer of at least @code{L_tmpnam} bytes, 8 or be @code{NULL}. Use of this function creates a security risk, and it must 9 not 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 24 static char tmpnam_buffer[L_tmpnam]; 25 static int tmpnam_counter; 26 27 extern int getpid (void); 28 29 char * tmpnam(char * s)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