1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "mounts.h" 18 19 #include <errno.h> 20 #include <fcntl.h> 21 #include <mntent.h> 22 #include <stdio.h> 23 #include <stdlib.h> 24 #include <string.h> 25 #include <sys/mount.h> 26 27 #include <string> 28 #include <vector> 29 30 struct MountedVolume { 31 std::string device; 32 std::string mount_point; 33 std::string filesystem; 34 std::string flags; 35 }; 36 37 std::vector<MountedVolume*> g_mounts_state; 38 39 bool scan_mounted_volumes() { 40 for (size_t i = 0; i < g_mounts_state.size(); ++i) { 41 delete g_mounts_state[i]; 42 } 43 g_mounts_state.clear(); 44 45 // Open and read mount table entries. 46 FILE* fp = setmntent("/proc/mounts", "re"); 47 if (fp == NULL) { 48 return false; 49 } 50 mntent* e; 51 while ((e = getmntent(fp)) != NULL) { 52 MountedVolume* v = new MountedVolume; 53 v->device = e->mnt_fsname; 54 v->mount_point = e->mnt_dir; 55 v->filesystem = e->mnt_type; 56 v->flags = e->mnt_opts; 57 g_mounts_state.push_back(v); 58 } 59 endmntent(fp); 60 return true; 61 } 62 63 MountedVolume* find_mounted_volume_by_device(const char* device) { 64 for (size_t i = 0; i < g_mounts_state.size(); ++i) { 65 if (g_mounts_state[i]->device == device) return g_mounts_state[i]; 66 } 67 return nullptr; 68 } 69 70 MountedVolume* find_mounted_volume_by_mount_point(const char* mount_point) { 71 for (size_t i = 0; i < g_mounts_state.size(); ++i) { 72 if (g_mounts_state[i]->mount_point == mount_point) return g_mounts_state[i]; 73 } 74 return nullptr; 75 } 76 77 int unmount_mounted_volume(MountedVolume* volume) { 78 // Intentionally pass the empty string to umount if the caller tries 79 // to unmount a volume they already unmounted using this 80 // function. 81 std::string mount_point = volume->mount_point; 82 volume->mount_point.clear(); 83 return umount(mount_point.c_str()); 84 } 85 86 int remount_read_only(MountedVolume* volume) { 87 return mount(volume->device.c_str(), volume->mount_point.c_str(), volume->filesystem.c_str(), 88 MS_NOATIME | MS_NODEV | MS_NODIRATIME | MS_RDONLY | MS_REMOUNT, 0); 89 } 90
