X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=blobdiff_plain;f=support%2Fmisc%2Fmountpoint.c;fp=support%2Fmisc%2Fmountpoint.c;h=6d0f34eab4954826fd636dcf3a5dd4f1eef6b35f;hp=0000000000000000000000000000000000000000;hb=d38ea02d0e4bcdc4e0114567028596f7bcba45b9;hpb=936ecbb5750e0e29b9e2464998a8e03eca617b72

diff --git a/support/misc/mountpoint.c b/support/misc/mountpoint.c
new file mode 100644
index 0000000..6d0f34e
--- /dev/null
+++ b/support/misc/mountpoint.c
@@ -0,0 +1,34 @@
+
+/*
+ * check if a given path is a mountpoint 
+ */
+
+#include <string.h>
+#include <malloc.h>
+#include <sys/stat.h>
+
+int
+is_mountpoint(char *path)
+{
+	/* 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;
+
+	dotdot = malloc(strlen(path)+4);
+	strcat(strcpy(dotdot, path), "/..");
+	if (lstat(path, &stb) != 0 ||
+	    lstat(dotdot, &pstb) != 0)
+		return 0;
+
+	if (stb.st_dev != pstb.st_dev
+	    || stb.st_ino == pstb.st_ino)
+		return 1;
+	return 0;
+}