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/* readable.c: check if a filename is a readable non-directory file.
Copyright 1993, 1995, 1996, 2008, 2011, 2012, 2016, 2018 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-namemx.h>
#include <kpathsea/c-pathch.h>
#include <kpathsea/c-pathmx.h>
#include <kpathsea/c-stat.h>
#include <kpathsea/pathsearch.h>
#include <kpathsea/readable.h>
#include <kpathsea/tex-hush.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(kpse, fn, st) \
(access ((fn), R_OK) == 0 && access ((fn), D_OK) == -1)
#elif defined (WIN32)
/* st must be an unsigned int under Windows */
static boolean
READABLE(kpathsea kpse, const_string fn, unsigned int st)
{
wchar_t *fnw;
fnw = get_wstring_from_mbstring(kpse->File_system_codepage, fn, fnw=NULL);
if ((st = GetFileAttributesW(fnw)) != 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;
}
}
if (fnw)
free (fnw);
return ((st != 0xFFFFFFFF) && !(st & FILE_ATTRIBUTE_DIRECTORY));
}
#else /* not __DJGPP__ and not WIN32 */
#define READABLE(kpse, 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 it can't be changed. */
string
kpathsea_readable_file (kpathsea kpse, string name)
{
#ifdef WIN32
unsigned int st = 0;
#else /* ! WIN32 */
struct stat st;
#endif
kpathsea_normalize_path (kpse, name);
if (READABLE (kpse, name, st)) {
return name;
#ifdef ENAMETOOLONG
} else if (errno == ENAMETOOLONG) {
/* Truncate any too-long components in NAME. */
unsigned c_len = 0; /* Length of current component. */
char *s = name; /* Position in current component. */
char *t = name; /* End of allowed length. */
for (; *s; s++) {
if (c_len <= NAME_MAX) {
t = s;
}
#if defined(WIN32)
if (kpathsea_IS_KANJI (kpse, s)) {
s++;
c_len += 2;
continue;
}
#endif /* WIN32 */
if (IS_DIR_SEP (*s) || IS_DEVICE_SEP (*s)) {
if (c_len > NAME_MAX) {
/* Truncate if past the max for a component. */
memmove (t, s, strlen (s) + 1);
s = t;
}
/* At a directory delimiter, reset component length. */
c_len = 0;
} else {
c_len++;
}
}
if (c_len > NAME_MAX) {
/* Truncate if past the max for last component. */
*t = 0;
}
/* Perhaps some other error will occur with the truncated name, so
let's call access again. */
if (READABLE (kpse, name, st)) /* Success. */
return name;
#endif /* ENAMETOOLONG */
} else { /* Some other error. */
if (errno == EACCES) { /* Maybe warn them if permissions are bad. */
if (!kpathsea_tex_hush (kpse, "readable")) {
perror (name);
}
}
}
return NULL;
}
#if defined (KPSE_COMPAT_API)
string
kpse_readable_file (string name)
{
return kpathsea_readable_file (kpse_def, name);
}
#endif
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