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

   1 /*
   2  * tmpname.c
   3  * Original Author:     G. Haley
   4  */
   5
   6 /*
   7 FUNCTION
   8 <<tmpnam>>, <<tempnam>>---name for a temporary file
   9
  10 INDEX
  11         tmpnam
  12 INDEX
  13         tempnam
  14 INDEX
  15         _tmpnam_r
  16 INDEX
  17         _tempnam_r
  18
  19 ANSI_SYNOPSIS
  20         #include <stdio.h>
  21         char *tmpnam(char *<[s]>);
  22         char *tempnam(char *<[dir]>, char *<[pfx]>);
  23         char *_tmpnam_r(void *<[reent]>, char *<[s]>);
  24         char *_tempnam_r(void *<[reent]>, char *<[dir]>, char *<[pfx]>);
  25
  26 TRAD_SYNOPSIS
  27         #include <stdio.h>
  28         char *tmpnam(<[s]>)
  29         char *<[s]>;
  30
  31         char *tempnam(<[dir]>, <[pfx]>)
  32         char *<[dir]>;
  33         char *<[pfx]>;
  34
  35         char *_tmpnam_r(<[reent]>, <[s]>)
  36         char *<[reent]>;
  37         char *<[s]>;
  38
  39         char *_tempnam_r(<[reent]>, <[dir]>, <[pfx]>)
  40         char *<[reent]>;
  41         char *<[dir]>;
  42         char *<[pfx]>;
  43
  44 DESCRIPTION
  45 Use either of these functions to generate a name for a temporary file.
  46 The generated name is guaranteed to avoid collision with other files
  47 (for up to <<TMP_MAX>> calls of either function).
  48
  49 <<tmpnam>> generates file names with the value of <<P_tmpdir>>
  50 (defined in `<<stdio.h>>') as the leading directory component of the path.
  51
  52 You can use the <<tmpnam>> argument <[s]> to specify a suitable area
  53 of memory for the generated filename; otherwise, you can call
  54 <<tmpnam(NULL)>> to use an internal static buffer.
  55
  56 <<tempnam>> allows you more control over the generated filename: you
  57 can use the argument <[dir]> to specify the path to a directory for
  58 temporary files, and you can use the argument <[pfx]> to specify a
  59 prefix for the base filename.
  60
  61 If <[dir]> is <<NULL>>, <<tempnam>> will attempt to use the value of
  62 environment variable <<TMPDIR>> instead; if there is no such value,
  63 <<tempnam>> uses the value of <<P_tmpdir>> (defined in `<<stdio.h>>').
  64
  65 If you don't need any particular prefix to the basename of temporary
  66 files, you can pass <<NULL>> as the <[pfx]> argument to <<tempnam>>.
  67
  68 <<_tmpnam_r>> and <<_tempnam_r>> are reentrant versions of <<tmpnam>>
  69 and <<tempnam>> respectively.  The extra argument <[reent]> is a
  70 pointer to a reentrancy structure.
  71
  72 WARNINGS
  73 The generated filenames are suitable for temporary files, but do not
  74 in themselves make files temporary.  Files with these names must still
  75 be explicitly removed when you no longer want them.
  76
  77 If you supply your own data area <[s]> for <<tmpnam>>, you must ensure
  78 that it has room for at least <<L_tmpnam>> elements of type <<char>>.
  79
  80 RETURNS
  81 Both <<tmpnam>> and <<tempnam>> return a pointer to the newly
  82 generated filename.
  83
  84 PORTABILITY
  85 ANSI C requires <<tmpnam>>, but does not specify the use of
  86 <<P_tmpdir>>.  The System V Interface Definition (Issue 2) requires
  87 both <<tmpnam>> and <<tempnam>>.
  88
  89 Supporting OS subroutines required: <<close>>,  <<fstat>>, <<getpid>>,
  90 <<isatty>>, <<lseek>>, <<open>>, <<read>>, <<sbrk>>, <<write>>.
  91
  92 The global pointer <<environ>> is also required.
  93 */
  94
  95 #include <_ansi.h>
  96 #include <stdio.h>
  97 #include <stdlib.h>
  98 #include <string.h>
  99 #include <fcntl.h>
 100 #include <reent.h>
 101 #include <errno.h>
 102
 103 /* Try to open the file specified, if it can't be opened then try
 104    another one.  Return nonzero if successful, otherwise zero.  */
 105
 106 static int
 107 worker (ptr, result, part1, part2, part3, part4)
 108      struct _reent *ptr;
 109      char *result;
 110      _CONST char *part1;
 111      _CONST char *part2;
 112      int part3;
 113      int *part4;
 114 {
 115   /*  Generate the filename and make sure that there isn't one called
 116       it already.  */
 117
 118   while (1)
 119     {
 120       int t;
 121       _sprintf_r (ptr, result, "%s/%s%x.%x", part1, part2, part3, *part4);
 122       (*part4)++;
 123       t = _open_r (ptr, result, O_RDONLY, 0);
 124       if (t == -1)
 125         {
 126           if (ptr->_errno == ENOSYS)
 127             {
 128               result[0] = '\0';
 129               return 0;
 130             }
 131           break;
 132         }
 133       _close_r (ptr, t);
 134     }
 135   return 1;
 136 }
 137
 138 char *
 139 _DEFUN (_tmpnam_r, (p, s),
 140         struct _reent *p _AND
 141         char *s)
 142 {
 143   char *result;
 144   int pid;
 145
 146   if (s == NULL)
 147     {
 148       /* ANSI states we must use an internal static buffer if s is NULL */
 149       _REENT_CHECK_EMERGENCY(p);
 150       result = _REENT_EMERGENCY(p);
 151     }
 152   else
 153     {
 154       result = s;
 155     }
 156   pid = _getpid_r (p);
 157
 158   if (worker (p, result, P_tmpdir, "t", pid, &p->_inc))
 159     {
 160       p->_inc++;
 161       return result;
 162     }
 163
 164   return NULL;
 165 }
 166
 167 char *
 168 _DEFUN (_tempnam_r, (p, dir, pfx),
 169         struct _reent *p _AND
 170         _CONST char *dir _AND
 171         _CONST char *pfx)
 172 {
 173   char *filename;
 174   int length;
 175   _CONST char *prefix = (pfx) ? pfx : "";
 176   if (dir == NULL && (dir = getenv ("TMPDIR")) == NULL)
 177     dir = P_tmpdir;
 178
 179   /* two 8 digit numbers + . / */
 180   length = strlen (dir) + strlen (prefix) + (4 * sizeof (int)) + 2 + 1;
 181
 182   filename = _malloc_r (p, length);
 183   if (filename)
 184     {
 185       if (! worker (p, filename, dir, prefix,
 186                     _getpid_r (p) ^ (int) (_POINTER_INT) p, &p->_inc))
 187         return NULL;
 188     }
 189   return filename;
 190 }
 191
 192 #ifndef _REENT_ONLY
 193
 194 char *
 195 _DEFUN (tempnam, (dir, pfx),
 196         _CONST char *dir _AND
 197         _CONST char *pfx)
 198 {
 199   return _tempnam_r (_REENT, dir, pfx);
 200 }
 201
 202 char *
 203 _DEFUN (tmpnam, (s),
 204         char *s)
 205 {
 206   return _tmpnam_r (_REENT, s);
 207 }
 208
 209 #endif