gcc/libgfortran/intrinsics/getcwd.c
Janne Blomqvist 16e60fff0b Fix stack overflow crash in getcwd intrinsic.
2014-05-12  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/61035
	* intrinsics/getcwd.c (getcwd_i4_sub): Avoid potentially large
	stack allocation, avoid extra copying in the common case.

From-SVN: r210335
2014-05-12 22:23:11 +03:00

99 lines
2.6 KiB
C

/* Implementation of the GETCWD intrinsic.
Copyright (C) 2004-2014 Free Software Foundation, Inc.
Contributed by Steven G. Kargl <kargls@comcast.net>.
This file is part of the GNU Fortran runtime library (libgfortran).
Libgfortran is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
Libgfortran 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 General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "libgfortran.h"
#include <string.h>
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_GETCWD
extern void getcwd_i4_sub (char *, GFC_INTEGER_4 *, gfc_charlen_type);
iexport_proto(getcwd_i4_sub);
void
getcwd_i4_sub (char *cwd, GFC_INTEGER_4 *status, gfc_charlen_type cwd_len)
{
int err;
if (getcwd (cwd, cwd_len))
{
size_t len = strlen (cwd);
memset (cwd + len, ' ', cwd_len - len);
err = 0;
}
else if (errno == ERANGE)
{
/* There is a possibility that the previous attempt failed due
to not enough space for the terminating null byte. Try again
with a buffer one char longer. */
char *buf = xmalloc (cwd_len + 1);
if (getcwd (buf, cwd_len + 1))
{
memcpy (cwd, buf, cwd_len);
err = 0;
}
else
err = errno;
free (buf);
}
else
err = errno;
if (err)
memset (cwd, ' ', cwd_len);
if (status != NULL)
*status = err;
}
iexport(getcwd_i4_sub);
extern void getcwd_i8_sub (char *, GFC_INTEGER_8 *, gfc_charlen_type);
export_proto(getcwd_i8_sub);
void
getcwd_i8_sub (char *cwd, GFC_INTEGER_8 *status, gfc_charlen_type cwd_len)
{
GFC_INTEGER_4 status4;
getcwd_i4_sub (cwd, &status4, cwd_len);
if (status)
*status = status4;
}
extern GFC_INTEGER_4 PREFIX(getcwd) (char *, gfc_charlen_type);
export_proto_np(PREFIX(getcwd));
GFC_INTEGER_4
PREFIX(getcwd) (char *cwd, gfc_charlen_type cwd_len)
{
GFC_INTEGER_4 status;
getcwd_i4_sub (cwd, &status, cwd_len);
return status;
}
#endif