/* Utility to pick a temporary filename prefix.

/* Utility to pick a temporary filename prefix.
Copyright (C) 1996-2024 Free Software Foundation, Inc.

This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Libiberty is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA. */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h> /* May get P_tmpdir. */
#include <sys/types.h>
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h> /* May get R_OK, etc. on some systems. */
#endif
#if defined(_WIN32) && !defined(__CYGWIN__)
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#ifndef R_OK
#define R_OK 4
#define W_OK 2
#define X_OK 1
#endif

#include "libiberty.h"
extern int mkstemps (char *, int);

/* '/' works just fine on MS-DOS based systems. */
#ifndef DIR_SEPARATOR
#define DIR_SEPARATOR '/'
#endif

/* Name of temporary file.
mktemp requires 6 trailing X's. */
#define TEMP_FILE "XXXXXX"
#define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)

#if !defined(_WIN32) || defined(__CYGWIN__)

/* Subroutine of choose_tmpdir.
If BASE is non-NULL, return it.
Otherwise it checks if DIR is a usable directory.
If success, DIR is returned.
Otherwise NULL is returned. */

static inline const char *try_dir (const char *, const char *);

static inline const char *
try_dir (const char *dir, const char *base)
{
if (base != 0)
return base;
if (dir != 0
&& access (dir, R_OK | W_OK | X_OK) == 0)
{
/* Check to make sure dir is actually a directory. */
#ifdef S_ISDIR
struct stat s;
if (stat (dir, &s))
return NULL;
if (!S_ISDIR (s.st_mode))
return NULL;
#endif
return dir;
}
return 0;
}

static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
static const char usrtmp[] =
{ DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
static const char vartmp[] =
{ DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };

#endif

static char *memoized_tmpdir;

/*

@deftypefn Replacement const char* choose_tmpdir ()

Returns a pointer to a directory path suitable for creating temporary
files in.

@end deftypefn

*/

const char *
choose_tmpdir (void)
{
if (!memoized_tmpdir)
{
#if !defined(_WIN32) || defined(__CYGWIN__)
const char *base = 0;
char *tmpdir;
unsigned int len;

#ifdef VMS
/* Try VMS standard temp logical. */
base = try_dir ("/sys$scratch", base);
#else
base = try_dir (getenv ("TMPDIR"), base);
base = try_dir (getenv ("TMP"), base);
base = try_dir (getenv ("TEMP"), base);
#endif

#ifdef P_tmpdir
/* We really want a directory name here as if concatenated with say \dir
we do not end up with a double \\ which defines an UNC path. */
if (strcmp (P_tmpdir, "\\") == 0)
base = try_dir ("\\.", base);
else
base = try_dir (P_tmpdir, base);
#endif

/* Try /tmp, /var/tmp, then /usr/tmp. */
base = try_dir (tmp, base);
base = try_dir (vartmp, base);
base = try_dir (usrtmp, base);

/* If all else fails, use the current directory! */
if (base == 0)
base = ".";
/* Append DIR_SEPARATOR to the directory we've chosen
and return it. */
len = strlen (base);
tmpdir = XNEWVEC (char, len + 2);
strcpy (tmpdir, base);
tmpdir[len] = DIR_SEPARATOR;
tmpdir[len+1] = '\0';
memoized_tmpdir = tmpdir;
#else /* defined(_WIN32) && !defined(__CYGWIN__) */
DWORD len;

/* Figure out how much space we need. */
len = GetTempPath(0, NULL);
if (len)
{
memoized_tmpdir = XNEWVEC (char, len);
if (!GetTempPath(len, memoized_tmpdir))
{
XDELETEVEC (memoized_tmpdir);
memoized_tmpdir = NULL;
}
}
if (!memoized_tmpdir)
/* If all else fails, use the current directory. */
memoized_tmpdir = xstrdup (".\\");
#endif /* defined(_WIN32) && !defined(__CYGWIN__) */
}

return memoized_tmpdir;
}

/*

@deftypefn Replacement char* make_temp_file (const char *@var{suffix})

Return a temporary file name (as a string) or @code{NULL} if unable to
create one. @var{suffix} is a suffix to append to the file name. The
string is @code{malloc}ed, and the temporary file has been created.

@end deftypefn

*/

char *
make_temp_file_with_prefix (const char *prefix, const char *suffix)
{
const char *base = choose_tmpdir ();
char *temp_filename;
int base_len, suffix_len, prefix_len;
int fd;

if (prefix == 0)
prefix = "cc";

if (suffix == 0)
suffix = "";

base_len = strlen (base);
prefix_len = strlen (prefix);
suffix_len = strlen (suffix);

temp_filename = XNEWVEC (char, base_len
+ TEMP_FILE_LEN
+ suffix_len
+ prefix_len + 1);
strcpy (temp_filename, base);
strcpy (temp_filename + base_len, prefix);
strcpy (temp_filename + base_len + prefix_len, TEMP_FILE);
strcpy (temp_filename + base_len + prefix_len + TEMP_FILE_LEN, suffix);

fd = mkstemps (temp_filename, suffix_len);
/* Mkstemps failed. It may be EPERM, ENOSPC etc. */
if (fd == -1)
{
fprintf (stderr, "Cannot create temporary file in %s: %s\n",
base, strerror (errno));
abort ();
}
/* We abort on failed close out of sheer paranoia. */
if (close (fd))
abort ();
return temp_filename;
}

char *
make_temp_file (const char *suffix)
{
return make_temp_file_with_prefix (NULL, suffix);
}