1 files changed, 117 insertions, 0 deletions
diff --git a/lib/lchown.c b/lib/lchown.c
new file mode 100644
index 0000000..105c2d9
--- /dev/null
+++ b/lib/lchown.c
@@ -0,0 +1,117 @@
+/* Provide a stub lchown function for systems that lack it.
+
+   Copyright (C) 1998-1999, 2002, 2004, 2006-2007, 2009-2022 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 */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include <errno.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#if !HAVE_LCHOWN
+
+/* If the system chown does not follow symlinks, we don't want it
+   replaced by gnulib's chown, which does follow symlinks.  */
+# if CHOWN_MODIFIES_SYMLINK
+#  undef chown
+# endif
+
+/* Work just like chown, except when FILE is a symbolic link.
+   In that case, set errno to EOPNOTSUPP and return -1.
+   But if autoconf tests determined that chown modifies
+   symlinks, then just call chown.  */
+
+int
+lchown (const char *file, uid_t uid, gid_t gid)
+{
+# if HAVE_CHOWN
+#  if ! CHOWN_MODIFIES_SYMLINK
+  struct stat stats;
+
+  if (lstat (file, &stats) == 0 && S_ISLNK (stats.st_mode))
+    {
+      errno = EOPNOTSUPP;
+      return -1;
+    }
+#  endif
+
+  return chown (file, uid, gid);
+
+# else /* !HAVE_CHOWN */
+  errno = ENOSYS;
+  return -1;
+# endif
+}
+
+#else /* HAVE_LCHOWN */
+
+# undef lchown
+
+/* Work around trailing slash bugs in lchown.  */
+int
+rpl_lchown (const char *file, uid_t uid, gid_t gid)
+{
+  bool stat_valid = false;
+  int result;
+
+# if CHOWN_CHANGE_TIME_BUG
+  struct stat st;
+
+  if (gid != (gid_t) -1 || uid != (uid_t) -1)
+    {
+      if (lstat (file, &st))
+        return -1;
+      stat_valid = true;
+      if (!S_ISLNK (st.st_mode))
+        return chown (file, uid, gid);
+    }
+# endif
+
+# if CHOWN_TRAILING_SLASH_BUG
+  if (!stat_valid)
+    {
+      size_t len = strlen (file);
+      if (len && file[len - 1] == '/')
+        return chown (file, uid, gid);
+    }
+# endif
+
+  result = lchown (file, uid, gid);
+
+# if CHOWN_CHANGE_TIME_BUG && HAVE_LCHMOD
+  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 lchown succeeded,
+         we assume that lchmod will do likewise.  But if the system
+         lacks lchmod and lutimes, we are out of luck.  Oh well.  */
+      result = lchmod (file, st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO
+                                           | S_ISUID | S_ISGID | S_ISVTX));
+    }
+# endif
+
+  return result;
+}
+
+#endif /* HAVE_LCHOWN */