toolchain/gcc/newlib/libc/stdio/mktemp.c

   1 /* This is file MKTEMP.C */
   2 /* This file may have been modified by DJ Delorie (Jan 1991).  If so,
   3 ** these modifications are Copyright (C) 1991 DJ Delorie.
   4 */
   5
   6 /*
   7  * Copyright (c) 1987 Regents of the University of California.
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms are permitted
  11  * provided that: (1) source distributions retain this entire copyright
  12  * notice and comment, and (2) distributions including binaries display
  13  * the following acknowledgement:  ``This product includes software
  14  * developed by the University of California, Berkeley and its contributors''
  15  * in the documentation or other materials provided with the distribution
  16  * and in all advertising materials mentioning features or use of this
  17  * software. Neither the name of the University nor the names of its
  18  * contributors may be used to endorse or promote products derived
  19  * from this software without specific prior written permission.
  20  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  21  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  22  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  23  */
  24
  25 /*
  26 FUNCTION
  27 <<mktemp>>, <<mkstemp>>---generate unused file name
  28
  29 INDEX
  30         mktemp
  31 INDEX
  32         mkstemp
  33 INDEX
  34         _mktemp_r
  35 INDEX
  36         _mkstemp_r
  37
  38 ANSI_SYNOPSIS
  39         #include <stdio.h>
  40         char *mktemp(char *<[path]>);
  41         int mkstemp(char *<[path]>);
  42
  43         char *_mktemp_r(void *<[reent]>, char *<[path]>);
  44         int *_mkstemp_r(void *<[reent]>, char *<[path]>);
  45
  46 TRAD_SYNOPSIS
  47         #include <stdio.h>
  48         char *mktemp(<[path]>)
  49         char *<[path]>;
  50
  51         int mkstemp(<[path]>)
  52         char *<[path]>;
  53
  54         char *_mktemp_r(<[reent]>, <[path]>)
  55         char *<[reent]>;
  56         char *<[path]>;
  57
  58         int _mkstemp_r(<[reent]>, <[path]>)
  59         char *<[reent]>;
  60         char *<[path]>;
  61
  62 DESCRIPTION
  63 <<mktemp>> and <<mkstemp>> attempt to generate a file name that is not
  64 yet in use for any existing file.  <<mkstemp>> creates the file and
  65 opens it for reading and writing; <<mktemp>> simply generates the file name.
  66
  67 You supply a simple pattern for the generated file name, as the string
  68 at <[path]>.  The pattern should be a valid filename (including path
  69 information if you wish) ending with some number of `<<X>>'
  70 characters.  The generated filename will match the leading part of the
  71 name you supply, with the trailing `<<X>>' characters replaced by some
  72 combination of digits and letters.
  73
  74 The alternate functions <<_mktemp_r>> and <<_mkstemp_r>> are reentrant
  75 versions.  The extra argument <[reent]> is a pointer to a reentrancy
  76 structure.
  77
  78 RETURNS
  79 <<mktemp>> returns the pointer <[path]> to the modified string
  80 representing an unused filename, unless it could not generate one, or
  81 the pattern you provided is not suitable for a filename; in that case,
  82 it returns <<NULL>>.
  83
  84 <<mkstemp>> returns a file descriptor to the newly created file,
  85 unless it could not generate an unused filename, or the pattern you
  86 provided is not suitable for a filename; in that case, it returns
  87 <<-1>>.
  88
  89 PORTABILITY
  90 ANSI C does not require either <<mktemp>> or <<mkstemp>>; the System
  91 V Interface Definition requires <<mktemp>> as of Issue 2.
  92
  93 Supporting OS subroutines required: <<getpid>>, <<open>>, <<stat>>.
  94 */
  95
  96 #include <sys/types.h>
  97 #include <fcntl.h>
  98 #include <sys/stat.h>
  99 #include <errno.h>
 100 #include <stdio.h>
 101 #include <ctype.h>
 102 #include <reent.h>
 103
 104 static int
 105 _DEFUN (_gettemp, (ptr, path, doopen),
 106         struct _reent *ptr _AND
 107         char *path _AND
 108         register int *doopen)
 109 {
 110   register char *start, *trv;
 111   struct stat sbuf;
 112   unsigned int pid;
 113
 114   pid = _getpid_r (ptr);
 115   for (trv = path; *trv; ++trv)         /* extra X's get set to 0's */
 116     continue;
 117   while (*--trv == 'X')
 118     {
 119       *trv = (pid % 10) + '0';
 120       pid /= 10;
 121     }
 122
 123   /*
 124    * Check the target directory; if you have six X's and it
 125    * doesn't exist this runs for a *very* long time.
 126    */
 127
 128   for (start = trv + 1;; --trv)
 129     {
 130       if (trv <= path)
 131         break;
 132       if (*trv == '/')
 133         {
 134           *trv = '\0';
 135 #ifdef __USE_INTERNAL_STAT64
 136           if (_stat64_r (ptr, path, &sbuf))
 137 #else
 138           if (_stat_r (ptr, path, &sbuf))
 139 #endif
 140             return (0);
 141           if (!(sbuf.st_mode & S_IFDIR))
 142             {
 143               ptr->_errno = ENOTDIR;
 144               return (0);
 145             }
 146           *trv = '/';
 147           break;
 148         }
 149     }
 150
 151   for (;;)
 152     {
 153       if (doopen)
 154         {
 155           if ((*doopen = _open_r (ptr, path, O_CREAT | O_EXCL | O_RDWR, 0600))
 156               >= 0)
 157             return 1;
 158 #if defined(__CYGWIN__)
 159           if (ptr->_errno != EEXIST && ptr->_errno != EACCES)
 160 #else
 161           if (ptr->_errno != EEXIST)
 162 #endif
 163             return 0;
 164         }
 165 #ifdef __USE_INTERNAL_STAT64
 166       else if (_stat64_r (ptr, path, &sbuf))
 167 #else
 168       else if (_stat_r (ptr, path, &sbuf))
 169 #endif
 170         return (ptr->_errno == ENOENT ? 1 : 0);
 171
 172       /* tricky little algorithm for backward compatibility */
 173       for (trv = start;;)
 174         {
 175           if (!*trv)
 176             return 0;
 177           if (*trv == 'z')
 178             *trv++ = 'a';
 179           else
 180             {
 181               if (isdigit (*trv))
 182                 *trv = 'a';
 183               else
 184                 ++ * trv;
 185               break;
 186             }
 187         }
 188     }
 189   /*NOTREACHED*/
 190 }
 191
 192 int
 193 _DEFUN (_mkstemp_r, (ptr, path),
 194         struct _reent *ptr _AND
 195         char *path)
 196 {
 197   int fd;
 198
 199   return (_gettemp (ptr, path, &fd) ? fd : -1);
 200 }
 201
 202 char *
 203 _DEFUN (_mktemp_r, (ptr, path),
 204         struct _reent *ptr _AND
 205         char *path)
 206 {
 207   return (_gettemp (ptr, path, (int *) NULL) ? path : (char *) NULL);
 208 }
 209
 210 #ifndef _REENT_ONLY
 211
 212 int
 213 _DEFUN (mkstemp, (path),
 214         char *path)
 215 {
 216   int fd;
 217
 218   return (_gettemp (_REENT, path, &fd) ? fd : -1);
 219 }
 220
 221 char *
 222 _DEFUN (mktemp, (path),
 223         char *path)
 224 {
 225   return (_gettemp (_REENT, path, (int *) NULL) ? path : (char *) NULL);
 226 }
 227
 228 #endif /* ! defined (_REENT_ONLY) */