1 files changed, 46 insertions, 0 deletions
diff --git a/support/misc/mountpoint.c b/support/misc/mountpoint.c
new file mode 100644
index 0000000..14d6731
--- /dev/null
+++ b/support/misc/mountpoint.c
@@ -0,0 +1,46 @@
+
+/*
+ * check if a given path is a mountpoint 
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include "xcommon.h"
+#include <sys/stat.h>
+#include "misc.h"
+
+int
+check_is_mountpoint(const char *path, int (mystat)(const char *, struct stat *))
+{
+	if (!mystat)
+		mystat = lstat;
+	/* Check if 'path' is a current mountpoint.
+	 * Possibly we should also check it is the mountpoint of the 
+	 * filesystem holding the target directory, but there doesn't
+	 * seem a lot of point.
+	 *
+	 * We deem it to be a mountpoint if appending a ".." gives a different
+	 * device or the same inode number.
+	 */
+	char *dotdot;
+	struct stat stb, pstb;
+	int rv;
+
+	dotdot = xmalloc(strlen(path)+4);
+
+	strcat(strcpy(dotdot, path), "/..");
+	if (mystat(path, &stb) != 0 ||
+	    mystat(dotdot, &pstb) != 0)
+		rv = 0;
+	else
+		if (stb.st_dev != pstb.st_dev ||
+		    stb.st_ino == pstb.st_ino)
+			rv = 1;
+		else
+			rv = 0;
+	free(dotdot);
+	return rv;
+}