/* readable.c: check if a filename is a readable non-directory file.
Copyright 1993, 1995, 1996, 2008 Karl Berry.
Copyright 1998, 1999, 2000, 2001, 2005 Olaf Weber.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, see <
http://www.gnu.org/licenses/>. */
#include <kpathsea/config.h>
#include <kpathsea/c-stat.h>
#include <kpathsea/pathsearch.h>
#include <kpathsea/readable.h>
#include <kpathsea/tex-hush.h>
#include <kpathsea/truncate.h>
/* If access can read FN, run stat (assigning to stat buffer ST) and
check that fn is not a directory. Don't check for just being a
regular file, as it is potentially useful to read fifo's or some
kinds of devices. */
#ifdef __DJGPP__
/* `stat' is way too expensive for such a simple job. */
#define READABLE(fn, st) \
(access (fn, R_OK) == 0 && access (fn, D_OK) == -1)
#elif WIN32
/* Warning: st must be an unsigned int under Win32 */
static boolean
READABLE(const_string fn, unsigned int st)
{
if ((st = GetFileAttributes(fn)) != 0xFFFFFFFF) {
/* succeeded */
errno = 0;
} else {
switch(GetLastError()) {
case ERROR_BUFFER_OVERFLOW:
errno = ENAMETOOLONG;
break;
case ERROR_ACCESS_DENIED:
errno = EACCES;
break;
default :
errno = EIO; /* meaningless, will make ret=NULL later */
break;
}
}
return ((st != 0xFFFFFFFF) &&
!(st & FILE_ATTRIBUTE_DIRECTORY));
}
#else
#define READABLE(fn, st) \
(access (fn, R_OK) == 0 && stat (fn, &(st)) == 0 && !S_ISDIR (st.st_mode))
#endif
/* POSIX invented the brain-damage of not necessarily truncating
filename components; the system's behavior is defined by the value of
the symbol _POSIX_NO_TRUNC, but you can't change it dynamically!
Generic const return warning. See extend-fname.c. */
string
kpathsea_readable_file (kpathsea kpse, const_string name)
{
string ret;
#ifdef WIN32
unsigned int st = 0;
#else /* ! WIN32 */
struct stat st;
#endif
kpathsea_normalize_path(kpse, (string)name);
if (READABLE (name, st)) {
ret = (string) name;
#ifdef ENAMETOOLONG
} else if (errno == ENAMETOOLONG) {
ret = kpathsea_truncate_filename (kpse, name);
/* Perhaps some other error will occur with the truncated name, so
let's call access again. */
if (!READABLE (ret, st)) { /* Failed. */
if (ret != name) free (ret);
ret = NULL;
}
#endif /* ENAMETOOLONG */
} else { /* Some other error. */
if (errno == EACCES) { /* Maybe warn them if permissions are bad. */
if (!kpathsea_tex_hush (kpse, "readable")) {
perror (name);
}
}
ret = NULL;
}
return ret;
}
#if defined (KPSE_COMPAT_API)
string
kpse_readable_file (const_string name)
{
return kpathsea_readable_file (kpse_def, name);
}
#endif
