diff options
author | Paul Eggert <eggert@cs.ucla.edu> | 2011-02-22 11:30:07 -0800 |
---|---|---|
committer | Paul Eggert <eggert@cs.ucla.edu> | 2011-02-22 11:30:07 -0800 |
commit | ae0d725005539d9259efac6a81ff8fdd45eb69a6 (patch) | |
tree | c721b530409b355281537abc7b058bdb2697ee01 /lib/readlink.c | |
parent | 8d40723d1e9661840a67ca7be9c5b073526ab421 (diff) |
[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/readlink.c')
-rw-r--r-- | lib/readlink.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/readlink.c b/lib/readlink.c new file mode 100644 index 0000000000..35d045b9a1 --- /dev/null +++ b/lib/readlink.c @@ -0,0 +1,74 @@ +/* Stub for readlink(). + Copyright (C) 2003-2007, 2009-2011 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/>. */ + +#include <config.h> + +/* Specification. */ +#include <unistd.h> + +#include <errno.h> +#include <string.h> +#include <sys/stat.h> + +#if !HAVE_READLINK + +/* readlink() substitute for systems that don't have a readlink() function, + such as DJGPP 2.03 and mingw32. */ + +ssize_t +readlink (const char *name, char *buf _GL_UNUSED, + size_t bufsize _GL_UNUSED) +{ + struct stat statbuf; + + /* In general we should use lstat() here, not stat(). But on platforms + without symbolic links, lstat() - if it exists - would be equivalent to + stat(), therefore we can use stat(). This saves us a configure check. */ + if (stat (name, &statbuf) >= 0) + errno = EINVAL; + return -1; +} + +#else /* HAVE_READLINK */ + +# undef readlink + +/* readlink() wrapper that uses correct types, for systems like cygwin + 1.5.x where readlink returns int, and which rejects trailing slash, + for Solaris 9. */ + +ssize_t +rpl_readlink (const char *name, char *buf, size_t bufsize) +{ +# if READLINK_TRAILING_SLASH_BUG + size_t len = strlen (name); + if (len && name[len - 1] == '/') + { + /* Even if name without the slash is a symlink to a directory, + both lstat() and stat() must resolve the trailing slash to + the directory rather than the symlink. We can therefore + safely use stat() to distinguish between EINVAL and + ENOTDIR/ENOENT, avoiding extra overhead of rpl_lstat(). */ + struct stat st; + if (stat (name, &st) == 0) + errno = EINVAL; + return -1; + } +# endif /* READLINK_TRAILING_SLASH_BUG */ + return readlink (name, buf, bufsize); +} + +#endif /* HAVE_READLINK */ |