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author | Paul Eggert <eggert@cs.ucla.edu> | 2011-02-22 11:30:07 -0800 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2011-02-22 11:30:07 -0800 |
commit | ae0d725005539d9259efac6a81ff8fdd45eb69a6 (patch) | |
tree | c721b530409b355281537abc7b058bdb2697ee01 /lib/lstat.c | |
parent | 8d40723d1e9661840a67ca7be9c5b073526ab421 (diff) | |
download | emacs-ae0d725005539d9259efac6a81ff8fdd45eb69a6.tar.gz |
[ChangeLog]
Work around some portability problems with symlinks.
* Makefile.in (GNULIB_MODULES): Add lstat, readlink, symlink.
* configure.in (lstat, HAVE_LSTAT): Remove special hack.
* lib/lstat.c, lib/readlink.c, lib/stat.c, lib/symlink.c:
* m4/dos.m4, m4/lstat.m4, m4/readlink.m4, m4/stat.m4, m4/symlink.m4:
New files, automatically generated from gnulib.
* aclocal.m4, configure, lib/Makefile.in, lib/gnulib.mk:
* lib/stdlib.in.h, m4/gl-comp.m4, m4/stdlib_h.m4: Regenerate.
2011-02-22 Paul Eggert <eggert@cs.ucla.edu>
[src/ChangeLog]
Work around some portability problems with symlinks.
* fileio.c (Frename_file, Fmake_symbolic_link, Ffile_symlink_p):
Simplify the code by assuming that the readlink and symlink calls
exist, even if they always fail on this host.
(Ffile_readable_p): Likewise, for fifos.
* config.in: Regenerate.
Diffstat (limited to 'lib/lstat.c')
-rw-r--r-- | lib/lstat.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/lib/lstat.c b/lib/lstat.c new file mode 100644 index 00000000000..b26065ede28 --- /dev/null +++ b/lib/lstat.c @@ -0,0 +1,91 @@ +/* Work around a bug of lstat on some systems + + Copyright (C) 1997-2006, 2008-2011 Free Software Foundation, Inc. + + This program 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. + + This program 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. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* written by Jim Meyering */ + +#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. */ +# define __need_system_sys_stat_h +# include <sys/types.h> +# include <sys/stat.h> +# undef __need_system_sys_stat_h + +static inline int +orig_lstat (const char *filename, struct stat *buf) +{ + return lstat (filename, buf); +} + +/* Specification. */ +# include <sys/stat.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) +{ + size_t len; + int lstat_result = orig_lstat (file, sbuf); + + if (lstat_result != 0) + return lstat_result; + + /* 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. */ + len = strlen (file); + if (file[len - 1] != '/' || S_ISDIR (sbuf->st_mode)) + return 0; + + /* At this point, a trailing slash is only permitted 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; + } + return stat (file, sbuf); +} + +#endif /* HAVE_LSTAT */ |