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-rw-r--r--lib/unlinkdir.c70
-rw-r--r--lib/unlinkdir.h27
2 files changed, 97 insertions, 0 deletions
diff --git a/lib/unlinkdir.c b/lib/unlinkdir.c
new file mode 100644
index 000000000..c30aa1020
--- /dev/null
+++ b/lib/unlinkdir.c
@@ -0,0 +1,70 @@
+/* unlinkdir.c - determine (and maybe change) whether we can unlink directories
+
+ Copyright (C) 2005 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 2, 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, write to the Free Software Foundation,
+ Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Written by Paul Eggert and Jim Meyering. */
+
+#include <config.h>
+
+#include "unlinkdir.h"
+
+#if HAVE_PRIV_H
+# include <priv.h>
+#endif
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if ! UNLINK_CANNOT_UNLINK_DIR
+
+/* Return true if we cannot unlink directories, false if we might be
+ able to unlink directories. If possible, tell the kernel we don't
+ want to be able to unlink directories, so that we can return true. */
+
+bool
+cannot_unlink_dir (void)
+{
+ static bool initialized;
+ static bool cannot;
+
+ if (! initialized)
+ {
+# if defined PRIV_EFFECTIVE && defined PRIV_SYS_LINKDIR
+ /* We might be able to unlink directories if we cannot
+ determine our privileges, or if we have the
+ PRIV_SYS_LINKDIR privilege and cannot delete it. */
+ priv_set_t *pset = priv_allocset ();
+ if (pset)
+ {
+ cannot =
+ (getppriv (PRIV_EFFECTIVE, pset) == 0
+ && (! priv_ismember (pset, PRIV_SYS_LINKDIR)
+ || (priv_delset (pset, PRIV_SYS_LINKDIR) == 0
+ && setppriv (PRIV_SET, PRIV_EFFECTIVE, pset) == 0)));
+ priv_freeset (pset);
+ }
+# else
+ /* In traditional Unix, only root can unlink directories. */
+ cannot = (getuid () != 0);
+# endif
+ }
+
+ initialized = true;
+ return cannot;
+}
+
+#endif
diff --git a/lib/unlinkdir.h b/lib/unlinkdir.h
new file mode 100644
index 000000000..f705f1233
--- /dev/null
+++ b/lib/unlinkdir.h
@@ -0,0 +1,27 @@
+/* unlinkdir.h - determine (and maybe change) whether we can unlink directories
+
+ Copyright (C) 2005 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 2, 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, write to the Free Software Foundation,
+ Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Written by Paul Eggert and Jim Meyering. */
+
+#include <stdbool.h>
+
+#if UNLINK_CANNOT_UNLINK_DIR
+static bool cannot_unlink_dir (void) { return true; }
+#else
+bool cannot_unlink_dir (void);
+#endif