| /* |
| * Copyright (C) 2008 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 "sysdeps.h" |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <mntent.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mount.h> |
| #include <unistd.h> |
| |
| #include "cutils/properties.h" |
| |
| #define TRACE_TAG TRACE_ADB |
| #include "adb.h" |
| |
| |
| static int system_ro = 1; |
| static int vendor_ro = 1; |
| |
| /* Returns the device used to mount a directory in /proc/mounts */ |
| static char *find_mount(const char *dir) |
| { |
| FILE* fp; |
| struct mntent* mentry; |
| char* device = NULL; |
| |
| if ((fp = setmntent("/proc/mounts", "r")) == NULL) { |
| return NULL; |
| } |
| while ((mentry = getmntent(fp)) != NULL) { |
| if (strcmp(dir, mentry->mnt_dir) == 0) { |
| device = strdup(mentry->mnt_fsname); |
| break; |
| } |
| } |
| endmntent(fp); |
| return device; |
| } |
| |
| static int hasVendorPartition() |
| { |
| struct stat info; |
| if (!lstat("/vendor", &info)) |
| if ((info.st_mode & S_IFMT) == S_IFDIR) |
| return true; |
| return false; |
| } |
| |
| static int make_block_device_writable(const char* dir) |
| { |
| char *dev = 0; |
| int fd = -1; |
| int OFF = 0; |
| int rc = -1; |
| |
| dev = find_mount(dir); |
| if (!dev) |
| goto errout; |
| |
| fd = unix_open(dev, O_RDONLY | O_CLOEXEC); |
| if (fd < 0) |
| goto errout; |
| |
| if (ioctl(fd, BLKROSET, &OFF)) { |
| goto errout; |
| } |
| |
| rc = 0; |
| |
| errout: |
| if (fd >= 0) { |
| adb_close(fd); |
| } |
| |
| if (dev) { |
| free(dev); |
| } |
| return rc; |
| } |
| |
| /* Init mounts /system as read only, remount to enable writes. */ |
| static int remount(const char* dir, int* dir_ro) |
| { |
| char *dev; |
| |
| if (dir_ro == 0) { |
| return 0; |
| } |
| |
| if (make_block_device_writable(dir)) { |
| return -1; |
| } |
| |
| dev = find_mount(dir); |
| |
| if (!dev) |
| return -1; |
| |
| *dir_ro = mount(dev, dir, "none", MS_REMOUNT, NULL); |
| |
| free(dev); |
| |
| return *dir_ro; |
| } |
| |
| static void write_string(int fd, const char* str) |
| { |
| writex(fd, str, strlen(str)); |
| } |
| |
| int make_system_and_vendor_block_devices_writable(int fd) |
| { |
| char buffer[200]; |
| if (make_block_device_writable("/system")) { |
| snprintf(buffer, sizeof(buffer), |
| "Failed to make system block device writable %s\n", |
| strerror(errno)); |
| write_string(fd, buffer); |
| return -1; |
| } |
| |
| if (hasVendorPartition() && make_block_device_writable("/vendor")) { |
| snprintf(buffer, sizeof(buffer), |
| "Failed to make vendor block device writable: %s\n", |
| strerror(errno)); |
| write_string(fd, buffer); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| void remount_service(int fd, void *cookie) |
| { |
| char buffer[200]; |
| char prop_buf[PROPERTY_VALUE_MAX]; |
| |
| bool system_verified = false, vendor_verified = false; |
| property_get("partition.system.verified", prop_buf, "0"); |
| if (!strcmp(prop_buf, "1")) { |
| system_verified = true; |
| } |
| |
| property_get("partition.vendor.verified", prop_buf, "0"); |
| if (!strcmp(prop_buf, "1")) { |
| vendor_verified = true; |
| } |
| |
| if (system_verified || vendor_verified) { |
| // Allow remount but warn of likely bad effects |
| bool both = system_verified && vendor_verified; |
| snprintf(buffer, sizeof(buffer), |
| "dm_verity is enabled on the %s%s%s partition%s.\n", |
| system_verified ? "system" : "", |
| both ? " and " : "", |
| vendor_verified ? "vendor" : "", |
| both ? "s" : ""); |
| write_string(fd, buffer); |
| snprintf(buffer, sizeof(buffer), |
| "Use \"adb disable-verity\" to disable verity.\n" |
| "If you do not, remount may succeed, however, you will still " |
| "not be able to write to these volumes.\n"); |
| write_string(fd, buffer); |
| } |
| |
| if (remount("/system", &system_ro)) { |
| snprintf(buffer, sizeof(buffer), "remount of system failed: %s\n",strerror(errno)); |
| write_string(fd, buffer); |
| } |
| |
| if (hasVendorPartition()) { |
| if (remount("/vendor", &vendor_ro)) { |
| snprintf(buffer, sizeof(buffer), "remount of vendor failed: %s\n",strerror(errno)); |
| write_string(fd, buffer); |
| } |
| } |
| |
| if (!system_ro && (!vendor_ro || !hasVendorPartition())) |
| write_string(fd, "remount succeeded\n"); |
| else { |
| write_string(fd, "remount failed\n"); |
| } |
| |
| adb_close(fd); |
| } |