1 files changed, 91 insertions, 0 deletions
diff --git a/package/toolbox/src/src/umount.c b/package/toolbox/src/src/umount.c
new file mode 100644
index 000000000..aee3bdd39
--- /dev/null
+++ b/package/toolbox/src/src/umount.c
@@ -0,0 +1,91 @@
+
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/loop.h>
+#include <errno.h>
+
+#define LOOPDEV_MAXLEN 64
+#define LOOP_MAJOR 7
+
+static int is_loop(char *dev)
+{
+    struct stat st;
+    int ret = 0;
+
+    if (stat(dev, &st) == 0) {
+        if (S_ISBLK(st.st_mode) && (major(st.st_rdev) == LOOP_MAJOR)) {
+            ret = 1;
+        }
+    }
+
+    return ret;
+}
+
+static int is_loop_mount(const char* path, char *loopdev)
+{
+    FILE* f;
+    int count;
+    char device[256];
+    char mount_path[256];
+    char rest[256];
+    int result = 0;
+    
+    f = fopen("/proc/mounts", "r");
+    if (!f) {
+        fprintf(stdout, "could not open /proc/mounts: %s\n", strerror(errno));
+        return -1;
+    }
+
+    do {
+        count = fscanf(f, "%255s %255s %255s\n", device, mount_path, rest);
+        if (count == 3) {
+            if (is_loop(device) && strcmp(path, mount_path) == 0) {
+                strlcpy(loopdev, device, LOOPDEV_MAXLEN);
+                result = 1;
+                break;
+            }
+        }
+    } while (count == 3);
+
+    fclose(f);
+    return result;
+}
+
+int main(int argc, char *argv[])
+{
+    int loop, loop_fd;
+    char loopdev[LOOPDEV_MAXLEN];
+
+    if(argc != 2) {
+        fprintf(stderr,"umount <path>\n");
+        return 1;
+    }
+
+    loop = is_loop_mount(argv[1], loopdev);
+    if (umount(argv[1])) {
+        fprintf(stderr, "failed: %s\n", strerror(errno));
+        return 1;
+    }
+
+    if (loop) {
+        // free the loop device
+        loop_fd = open(loopdev, O_RDONLY);
+        if (loop_fd < 0) {
+            fprintf(stderr, "open loop device failed: %s\n", strerror(errno));
+            return 1;
+        }
+        if (ioctl(loop_fd, LOOP_CLR_FD, 0) < 0) {
+            fprintf(stderr, "ioctl LOOP_CLR_FD failed: %s\n", strerror(errno));
+            return 1;
+        }
+
+        close(loop_fd);
+    }
+
+    return 0;
+}