Mercurial > gnulib
view lib/chown.c @ 40206:770a5696761e
relocatable-prog: Use wrapper-free installation on Mac OS X, take 2.
This approach supports relocatable installation of shared libraries
which depend on other shared libraries from the same package.
* m4/relocatable.m4 (gl_RELOCATABLE_BODY): Determine use_macos_tools.
If use_macos_tools is true, use reloc-ldflags and set LIBTOOL to be a
wrapper around the original LIBTOOL.
* build-aux/reloc-ldflags: Add support for Mac OS X, which uses the
token '@loader_path' instead of '$ORIGIN'.
* build-aux/libtool-reloc: New file.
* modules/relocatable-prog (Files): Add it.
* doc/relocatable-maint.texi (Supporting Relocation): Update to match
the recent changes. Document the need to set the *_LDFLAGS of libraries.
RELOCATABLE_LIBRARY_PATH and RELOCATABLE_CONFIG_H_DIR should be set in
Makefile.am, not in configure.ac.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Mon, 04 Mar 2019 17:25:09 +0100 |
parents | b06060465f09 |
children |
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/* provide consistent interface to chown for systems that don't interpret an ID of -1 as meaning "don't change the corresponding ID". Copyright (C) 1997, 2004-2007, 2009-2019 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 <https://www.gnu.org/licenses/>. */ /* written by Jim Meyering */ #include <config.h> /* Specification. */ #include <unistd.h> #include <errno.h> #include <fcntl.h> #include <stdbool.h> #include <string.h> #include <sys/stat.h> #if !HAVE_CHOWN /* Simple stub that always fails with ENOSYS, for mingw. */ int chown (const char *file _GL_UNUSED, uid_t uid _GL_UNUSED, gid_t gid _GL_UNUSED) { errno = ENOSYS; return -1; } #else /* HAVE_CHOWN */ /* Below we refer to the system's chown(). */ # undef chown /* Provide a more-closely POSIX-conforming version of chown on systems with one or both of the following problems: - chown doesn't treat an ID of -1 as meaning "don't change the corresponding ID". - chown doesn't dereference symlinks. */ int rpl_chown (const char *file, uid_t uid, gid_t gid) { struct stat st; bool stat_valid = false; int result; # if CHOWN_CHANGE_TIME_BUG if (gid != (gid_t) -1 || uid != (uid_t) -1) { if (stat (file, &st)) return -1; stat_valid = true; } # endif # if CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE if (gid == (gid_t) -1 || uid == (uid_t) -1) { /* Stat file to get id(s) that should remain unchanged. */ if (!stat_valid && stat (file, &st)) return -1; if (gid == (gid_t) -1) gid = st.st_gid; if (uid == (uid_t) -1) uid = st.st_uid; } # endif # if CHOWN_MODIFIES_SYMLINK { /* Handle the case in which the system-supplied chown function does *not* follow symlinks. Instead, it changes permissions on the symlink itself. To work around that, we open the file (but this can fail due to lack of read or write permission) and use fchown on the resulting descriptor. */ int open_flags = O_NONBLOCK | O_NOCTTY; int fd = open (file, O_RDONLY | open_flags); if (0 <= fd || (errno == EACCES && 0 <= (fd = open (file, O_WRONLY | open_flags)))) { int saved_errno; bool fchown_socket_failure; result = fchown (fd, uid, gid); saved_errno = errno; /* POSIX says fchown can fail with errno == EINVAL on sockets and pipes, so fall back on chown in that case. */ fchown_socket_failure = (result != 0 && saved_errno == EINVAL && fstat (fd, &st) == 0 && (S_ISFIFO (st.st_mode) || S_ISSOCK (st.st_mode))); close (fd); if (! fchown_socket_failure) { errno = saved_errno; return result; } } else if (errno != EACCES) return -1; } # endif # if CHOWN_TRAILING_SLASH_BUG if (!stat_valid) { size_t len = strlen (file); if (len && file[len - 1] == '/' && stat (file, &st)) return -1; } # endif result = chown (file, uid, gid); # if CHOWN_CHANGE_TIME_BUG if (result == 0 && stat_valid && (uid == st.st_uid || uid == (uid_t) -1) && (gid == st.st_gid || gid == (gid_t) -1)) { /* No change in ownership, but at least one argument was not -1, so we are required to update ctime. Since chown succeeded, we assume that chmod will do likewise. Fortunately, on all known systems where a 'no-op' chown skips the ctime update, a 'no-op' chmod still does the trick. */ result = chmod (file, st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID | S_ISVTX)); } # endif return result; } #endif /* HAVE_CHOWN */