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/* 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
#ifndef __STDC_NO_THREADS__
#include <threads.h>
extern mtx_t _PDCLIB_filelist_mtx;
#endif
#include "pdclib/_PDCLIB_glue.h"
#include "pdclib/_PDCLIB_defguard.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.
*/
int randomsource = open( "/dev/urandom", O_RDONLY );
/* Working under the assumption that the tempfile location is canonical
(absolute), and does not require going through _PDCLIB_realpath().
*/
char * filename = ( char * )malloc( L_tmpnam );
_PDCLIB_fd_t fd;
if ( randomsource == -1 )
{
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;
read( randomsource, (void *)&random, sizeof( unsigned int ) );
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 )
{
/* Found a file that does not exist yet */
break;
}
close( fd );
}
close( randomsource );
/* See fopen(), which does much of the same. */
if ( ( rc = _PDCLIB_init_file_t( NULL ) ) == NULL )
{
/* initializing FILE structure failed */
close( fd );
return NULL;
}
rc->status |= _PDCLIB_filemode( "wb+" ) | _IOLBF | _PDCLIB_DELONCLOSE;
rc->handle = fd;
/* Filename (for potential freopen()) */
rc->filename = filename;
/* Adding to list of open files */
_PDCLIB_LOCK( _PDCLIB_filelist_mtx );
rc->next = _PDCLIB_filelist;
_PDCLIB_filelist = rc;
_PDCLIB_UNLOCK( _PDCLIB_filelist_mtx );
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
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