1 files changed, 74 insertions, 0 deletions
diff --git a/toolbox/umount.c b/toolbox/umount.c
new file mode 100644
index 0000000..92c6076
--- /dev/null
+++ b/toolbox/umount.c
@@ -0,0 +1,74 @@
+
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/loop.h>
+
+// FIXME - only one loop mount is supported at a time
+#define LOOP_DEVICE "/dev/block/loop0"
+
+static int is_loop_mount(const char* path)
+{
+    FILE* f;
+    int count;
+    char device[256];
+    char mount_path[256];
+    char rest[256];
+    int result = 0;
+    int path_length = strlen(path);
+    
+    f = fopen("/proc/mounts", "r");
+    if (!f) {
+        fprintf(stdout, "could not open /proc/mounts\n");
+        return -1;
+    }
+
+    do {
+        count = fscanf(f, "%255s %255s %255s\n", device, mount_path, rest);
+        if (count == 3) {
+            if (strcmp(LOOP_DEVICE, device) == 0 && strcmp(path, mount_path) == 0) {
+                result = 1;
+                break;
+            }
+        }
+    } while (count == 3);
+
+    fclose(f);
+    return result;
+}
+
+int umount_main(int argc, char *argv[])
+{
+    int loop, loop_fd;
+    
+    if(argc != 2) {
+        fprintf(stderr,"umount <path>\n");
+        return 1;
+    }
+
+    loop = is_loop_mount(argv[1]);
+    if(umount(argv[1])){
+        fprintf(stderr,"failed.\n");
+        return 1;
+    }
+
+    if (loop) {
+        // free the loop device
+        loop_fd = open(LOOP_DEVICE, O_RDONLY);
+        if (loop_fd < -1) {
+            perror("open loop device failed");
+            return 1;
+        }
+        if (ioctl(loop_fd, LOOP_CLR_FD, 0) < 0) {
+            perror("ioctl LOOP_CLR_FD failed");
+            return 1;
+        }
+
+        close(loop_fd);
+    }
+
+    return 0;
+}