2.11BSD#431 - /usr/src/lib/libc/gen/mktemp.c

   1: /*
   2:  * Copyright (c) 1987 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #if defined(LIBC_SCCS) && !defined(lint)
   8: static char sccsid[] = "@(#)mktemp.c	5.4 (Berkeley) 9/14/87";
   9: #endif LIBC_SCCS and not lint
  10: 
  11: #include <sys/types.h>
  12: #include <sys/file.h>
  13: #include <sys/stat.h>
  14: #include <errno.h>
  15: #include <stdio.h>
  16: #include <ctype.h>
  17: 
  18: #define YES 1
  19: #define NO  0
  20: 
  21: mkstemp(as)
  22:     char    *as;
  23: {
  24:     int fd;
  25: 
  26:     return (_gettemp(as, &fd) ? fd : -1);
  27: }
  28: 
  29: char *
  30: mktemp(as)
  31:     char    *as;
  32: {
  33:     return(_gettemp(as, (int *)NULL) ? as : (char *)NULL);
  34: }
  35: 
  36: static
  37: _gettemp(as, doopen)
  38:     char    *as;
  39:     register int    *doopen;
  40: {
  41:     extern int  errno;
  42:     register char   *start, *trv;
  43:     struct stat sbuf;
  44:     u_int   pid;
  45: 
  46:     pid = getpid();
  47: 
  48:     /* extra X's get set to 0's */
  49:     for (trv = as; *trv; ++trv);
  50:     while (*--trv == 'X') {
  51:         *trv = (pid % 10) + '0';
  52:         pid /= 10;
  53:     }
  54: 
  55:     /*
  56: 	 * check for write permission on target directory; if you have
  57: 	 * six X's and you can't write the directory, this will run for
  58: 	 * a *very* long time.
  59: 	 */
  60:     for (start = ++trv; trv > as && *trv != '/'; --trv);
  61:     if (*trv == '/') {
  62:         *trv = '\0';
  63:         if (stat(as, &sbuf) || !(sbuf.st_mode & S_IFDIR))
  64:             return(NO);
  65:         *trv = '/';
  66:     }
  67:     else if (stat(".", &sbuf) == -1)
  68:         return(NO);
  69: 
  70:     for (;;) {
  71:         if (doopen) {
  72:             if ((*doopen = open(as, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
  73:             return(YES);
  74:             if (errno != EEXIST)
  75:             return(NO);
  76:         }
  77:         else if (stat(as, &sbuf))
  78:             return(errno == ENOENT ? YES : NO);
  79: 
  80:         /* tricky little algorithm for backward compatibility */
  81:         for (trv = start;;) {
  82:             if (!*trv)
  83:                 return(NO);
  84:             if (*trv == 'z')
  85:                 *trv++ = 'a';
  86:             else {
  87:                 if (isdigit(*trv))
  88:                     *trv = 'a';
  89:                 else
  90:                     ++*trv;
  91:                 break;
  92:             }
  93:         }
  94:     }
  95:     /*NOTREACHED*/
  96: }

Defined functions

Defined variables

Defined macros