118 lines
3.0 KiB
C
118 lines
3.0 KiB
C
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/* Provide a stub lchown function for systems that lack it.
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Copyright (C) 1998-1999, 2002, 2004, 2006-2007, 2009-2020 Free Software
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Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* written by Jim Meyering */
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#include <config.h>
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#include <unistd.h>
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#include <errno.h>
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#include <stdbool.h>
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#include <string.h>
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#include <sys/stat.h>
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#if !HAVE_LCHOWN
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/* If the system chown does not follow symlinks, we don't want it
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replaced by gnulib's chown, which does follow symlinks. */
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# if CHOWN_MODIFIES_SYMLINK
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# undef chown
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# endif
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/* Work just like chown, except when FILE is a symbolic link.
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In that case, set errno to EOPNOTSUPP and return -1.
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But if autoconf tests determined that chown modifies
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symlinks, then just call chown. */
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int
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lchown (const char *file, uid_t uid, gid_t gid)
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{
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# if HAVE_CHOWN
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# if ! CHOWN_MODIFIES_SYMLINK
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struct stat stats;
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if (lstat (file, &stats) == 0 && S_ISLNK (stats.st_mode))
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{
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errno = EOPNOTSUPP;
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return -1;
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}
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# endif
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return chown (file, uid, gid);
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# else /* !HAVE_CHOWN */
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errno = ENOSYS;
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return -1;
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# endif
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}
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#else /* HAVE_LCHOWN */
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# undef lchown
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/* Work around trailing slash bugs in lchown. */
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int
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rpl_lchown (const char *file, uid_t uid, gid_t gid)
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{
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bool stat_valid = false;
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int result;
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# if CHOWN_CHANGE_TIME_BUG
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struct stat st;
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if (gid != (gid_t) -1 || uid != (uid_t) -1)
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{
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if (lstat (file, &st))
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return -1;
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stat_valid = true;
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if (!S_ISLNK (st.st_mode))
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return chown (file, uid, gid);
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}
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# endif
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# if CHOWN_TRAILING_SLASH_BUG
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if (!stat_valid)
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{
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size_t len = strlen (file);
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if (len && file[len - 1] == '/')
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return chown (file, uid, gid);
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}
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# endif
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result = lchown (file, uid, gid);
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# if CHOWN_CHANGE_TIME_BUG && HAVE_LCHMOD
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if (result == 0 && stat_valid
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&& (uid == st.st_uid || uid == (uid_t) -1)
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&& (gid == st.st_gid || gid == (gid_t) -1))
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{
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/* No change in ownership, but at least one argument was not -1,
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so we are required to update ctime. Since lchown succeeded,
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we assume that lchmod will do likewise. But if the system
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lacks lchmod and lutimes, we are out of luck. Oh well. */
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result = lchmod (file, st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO
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| S_ISUID | S_ISGID | S_ISVTX));
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}
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# endif
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return result;
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}
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#endif /* HAVE_LCHOWN */
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