/* Copyright (C) 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id$ */
/* Miscellaneous support for platform facilities */

#include "unistd_.h"
#include "fcntl_.h"
#include "stdio_.h"
#include "stat_.h"
#include "gp.h"
#include "gpgetenv.h"
#include "gpmisc.h"

/*
 * Get the name of the directory for temporary files, if any.  Currently
 * this checks the TMPDIR and TEMP environment variables, in that order.
 * The return value and the setting of *ptr and *plen are as for gp_getenv.
 */
int
gp_gettmpdir(char *ptr, int *plen)
{
    int max_len = *plen;
    int code = gp_getenv("TMPDIR", ptr, plen);

    if (code != 1)
	return code;
    *plen = max_len;
    return gp_getenv("TEMP", ptr, plen);
}

/*
 * Open a temporary file, using O_EXCL and S_I*USR to prevent race
 * conditions and symlink attacks.
 */
FILE *
gp_fopentemp(const char *fname, const char *mode)
{
    int flags = O_EXCL;
    /* Scan the mode to construct the flags. */
    const char *p = mode;
    int fildes;
    FILE *file;

    while (*p)
	switch (*p++) {
	case 'a':
	    flags |= O_CREAT | O_APPEND;
	    break;
	case 'r':
	    flags |= O_RDONLY;
	    break;
	case 'w':
	    flags |= O_CREAT | O_WRONLY | O_TRUNC;
	    break;
#ifdef O_BINARY
	    /* Watcom C insists on this non-ANSI flag being set. */
	case 'b':
	    flags |= O_BINARY;
	    break;
#endif
	case '+':
	    flags = (flags & ~(O_RDONLY | O_WRONLY)) | O_RDWR;
	    break;
	default:		/* e.g., 'b' */
	    break;
	}
    fildes = open(fname, flags, S_IRUSR | S_IWUSR);
    if (fildes < 0)
	return 0;
    /*
     * The DEC VMS C compiler incorrectly defines the second argument of
     * fdopen as (char *), rather than following the POSIX.1 standard,
     * which defines it as (const char *).  Patch this here.
     */
    file = fdopen(fildes, (char *)mode); /* still really const */
    if (file == 0)
	close(fildes);
    return file;
}