1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
/* tmpfile( void )
This file is part of the Public Domain C Library (PDCLib).
Permission is granted to use, modify, and / or redistribute at will.
*/
#include <stdio.h>
#ifndef REGTEST
#include "pdclib/_PDCLIB_glue.h"
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
extern struct _PDCLIB_file_t * _PDCLIB_filelist;
/* This is an example implementation of tmpfile() fit for use with POSIX
kernels.
*/
struct _PDCLIB_file_t * tmpfile( void )
{
FILE * rc;
/* This is the chosen way to get high-quality randomness. Replace as
appropriate.
*/
FILE * randomsource = fopen( "/proc/sys/kernel/random/uuid", "rb" );
char filename[ L_tmpnam ];
_PDCLIB_fd_t fd;
if ( randomsource == NULL )
{
return NULL;
}
for ( ;; )
{
/* Get a filename candidate. What constitutes a valid filename and
where temporary files are usually located is platform-dependent,
which is one reason why this function is located in the platform
overlay. The other reason is that a *good* implementation should
use high-quality randomness instead of a pseudo-random sequence to
generate the filename candidate, which is *also* platform-dependent.
*/
unsigned int random;
fscanf( randomsource, "%u", &random );
sprintf( filename, "/tmp/%u.tmp", random );
/* Check if file of this name exists. Note that fopen() is a very weak
check, which does not take e.g. access permissions into account
(file might exist but not readable). Replace with something more
appropriate.
*/
fd = open( filename, O_CREAT | O_EXCL | O_RDWR, S_IRUSR | S_IWUSR );
if ( fd != -1 )
{
break;
}
close( fd );
}
fclose( randomsource );
/* See fopen(). */
if ( ( rc = calloc( 1, sizeof( struct _PDCLIB_file_t ) + _PDCLIB_UNGETCBUFSIZE + L_tmpnam + BUFSIZ ) ) == NULL )
{
/* No memory to set up FILE structure */
close( fd );
return NULL;
}
rc->status = _PDCLIB_filemode( "wb+" ) | _IOLBF | _PDCLIB_DELONCLOSE;
rc->handle = fd;
rc->ungetbuf = (unsigned char *)rc + sizeof( struct _PDCLIB_file_t );
rc->filename = (char *)rc->ungetbuf + _PDCLIB_UNGETCBUFSIZE;
rc->buffer = rc->filename + L_tmpnam;
strcpy( rc->filename, filename );
rc->bufsize = BUFSIZ;
rc->bufidx = 0;
rc->ungetidx = 0;
rc->next = _PDCLIB_filelist;
_PDCLIB_filelist = rc;
return rc;
}
#endif
#ifdef TEST
#include "_PDCLIB_test.h"
#include <string.h>
int main( void )
{
FILE * fh;
#ifndef REGTEST
char filename[ L_tmpnam ];
FILE * fhtest;
#endif
TESTCASE( ( fh = tmpfile() ) != NULL );
TESTCASE( fputc( 'x', fh ) == 'x' );
/* Checking that file is actually there */
TESTCASE_NOREG( strcpy( filename, fh->filename ) == filename );
TESTCASE_NOREG( ( fhtest = fopen( filename, "r" ) ) != NULL );
TESTCASE_NOREG( fclose( fhtest ) == 0 );
/* Closing tmpfile */
TESTCASE( fclose( fh ) == 0 );
/* Checking that file was deleted */
TESTCASE_NOREG( fopen( filename, "r" ) == NULL );
return TEST_RESULTS;
}
#endif
|
