* platform/example is now a "stub" platform - it should compile anywhere, but

[pdclib] / platform / posix / functions / stdio / tmpfile.c

diff --git a/platform/posix/functions/stdio/tmpfile.c b/platform/posix/functions/stdio/tmpfile.c
new file mode 100644 (file)
index 0000000..29750d4
--- /dev/null
+++ b/platform/posix/functions/stdio/tmpfile.c
@@ -0,0 +1,115 @@
+/* $Id$ */
+
+/* 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 <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <_PDCLIB_glue.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
+