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nano-7.2/lib/lstat.c

105 lines
3.7 KiB
C

/* Work around a bug of lstat on some systems
Copyright (C) 1997-2006, 2008-2023 Free Software Foundation, Inc.
This file 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 file 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 program. If not, see <https://www.gnu.org/licenses/>. */
/* written by Jim Meyering */
/* If the user's config.h happens to include <sys/stat.h>, let it include only
the system's <sys/stat.h> here, so that orig_lstat doesn't recurse to
rpl_lstat. */
#define __need_system_sys_stat_h
#include <config.h>
#if !HAVE_LSTAT
/* On systems that lack symlinks, our replacement <sys/stat.h> already
defined lstat as stat, so there is nothing further to do other than
avoid an empty file. */
typedef int dummy;
#else /* HAVE_LSTAT */
/* Get the original definition of lstat. It might be defined as a macro. */
# include <sys/types.h>
# include <sys/stat.h>
# undef __need_system_sys_stat_h
static int
orig_lstat (const char *filename, struct stat *buf)
{
return lstat (filename, buf);
}
/* Specification. */
# ifdef __osf__
/* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
eliminates this include because of the preliminary #include <sys/stat.h>
above. */
# include "sys/stat.h"
# else
# include <sys/stat.h>
# endif
# include "stat-time.h"
# include <string.h>
# include <errno.h>
/* lstat works differently on Linux and Solaris systems. POSIX (see
"pathname resolution" in the glossary) requires that programs like
'ls' take into consideration the fact that FILE has a trailing slash
when FILE is a symbolic link. On Linux and Solaris 10 systems, the
lstat function already has the desired semantics (in treating
'lstat ("symlink/", sbuf)' just like 'lstat ("symlink/.", sbuf)',
but on Solaris 9 and earlier it does not.
If FILE has a trailing slash and specifies a symbolic link,
then use stat() to get more info on the referent of FILE.
If the referent is a non-directory, then set errno to ENOTDIR
and return -1. Otherwise, return stat's result. */
int
rpl_lstat (const char *file, struct stat *sbuf)
{
int result = orig_lstat (file, sbuf);
/* This replacement file can blindly check against '/' rather than
using the ISSLASH macro, because all platforms with '\\' either
lack symlinks (mingw) or have working lstat (cygwin) and thus do
not compile this file. 0 len should have already been filtered
out above, with a failure return of ENOENT. */
if (result == 0)
{
if (S_ISDIR (sbuf->st_mode) || file[strlen (file) - 1] != '/')
result = stat_time_normalize (result, sbuf);
else
{
/* At this point, a trailing slash is permitted only on
symlink-to-dir; but it should have found information on the
directory, not the symlink. Call 'stat' to get info about the
link's referent. Our replacement stat guarantees valid results,
even if the symlink is not pointing to a directory. */
if (!S_ISLNK (sbuf->st_mode))
{
errno = ENOTDIR;
return -1;
}
result = stat (file, sbuf);
}
}
return result;
}
#endif /* HAVE_LSTAT */