1 files changed, 89 insertions, 0 deletions

diff --git a/mounts.cpp b/mounts.cpp
new file mode 100644
index 000000000..f23376b06
--- /dev/null
+++ b/mounts.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mounts.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <mntent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mount.h>
+
+#include <string>
+#include <vector>
+
+struct MountedVolume {
+    std::string device;
+    std::string mount_point;
+    std::string filesystem;
+    std::string flags;
+};
+
+std::vector<MountedVolume*> g_mounts_state;
+
+bool scan_mounted_volumes() {
+    for (size_t i = 0; i < g_mounts_state.size(); ++i) {
+        delete g_mounts_state[i];
+    }
+    g_mounts_state.clear();
+
+    // Open and read mount table entries.
+    FILE* fp = setmntent("/proc/mounts", "re");
+    if (fp == NULL) {
+        return false;
+    }
+    mntent* e;
+    while ((e = getmntent(fp)) != NULL) {
+        MountedVolume* v = new MountedVolume;
+        v->device = e->mnt_fsname;
+        v->mount_point = e->mnt_dir;
+        v->filesystem = e->mnt_type;
+        v->flags = e->mnt_opts;
+        g_mounts_state.push_back(v);
+    }
+    endmntent(fp);
+    return true;
+}
+
+MountedVolume* find_mounted_volume_by_device(const char* device) {
+    for (size_t i = 0; i < g_mounts_state.size(); ++i) {
+        if (g_mounts_state[i]->device == device) return g_mounts_state[i];
+    }
+    return nullptr;
+}
+
+MountedVolume* find_mounted_volume_by_mount_point(const char* mount_point) {
+    for (size_t i = 0; i < g_mounts_state.size(); ++i) {
+        if (g_mounts_state[i]->mount_point == mount_point) return g_mounts_state[i];
+    }
+    return nullptr;
+}
+
+int unmount_mounted_volume(MountedVolume* volume) {
+    // Intentionally pass the empty string to umount if the caller tries
+    // to unmount a volume they already unmounted using this
+    // function.
+    std::string mount_point = volume->mount_point;
+    volume->mount_point.clear();
+    return umount(mount_point.c_str());
+}
+
+int remount_read_only(MountedVolume* volume) {
+    return mount(volume->device.c_str(), volume->mount_point.c_str(), volume->filesystem.c_str(),
+                 MS_NOATIME | MS_NODEV | MS_NODIRATIME | MS_RDONLY | MS_REMOUNT, 0);
+}