remount_service.cpp revision ffdec180176094dac0fb902263370dea1deb138f
1dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project/* 2dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * Copyright (C) 2008 The Android Open Source Project 3dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * 4dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 5dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * you may not use this file except in compliance with the License. 6dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * You may obtain a copy of the License at 7dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * 8dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 9dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * 10dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 11dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 12dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * See the License for the specific language governing permissions and 14dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project * limitations under the License. 15dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project */ 16dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 17aed3c61c4437ebb05eadfb3bf85d6962c30b9935Yabin Cui#define TRACE_TAG ADB 183313426fad9eaaf53017cdbde889ebcec91358ecDan Albert 193313426fad9eaaf53017cdbde889ebcec91358ecDan Albert#include "sysdeps.h" 203313426fad9eaaf53017cdbde889ebcec91358ecDan Albert 2160299dfd6a5dca059a079bc8e11d45a1fecf02d0Mark Salyzyn#include <errno.h> 2260299dfd6a5dca059a079bc8e11d45a1fecf02d0Mark Salyzyn#include <fcntl.h> 23d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui#include <mntent.h> 24dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project#include <stdio.h> 2560299dfd6a5dca059a079bc8e11d45a1fecf02d0Mark Salyzyn#include <stdlib.h> 26dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project#include <string.h> 27dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project#include <sys/mount.h> 2860299dfd6a5dca059a079bc8e11d45a1fecf02d0Mark Salyzyn#include <unistd.h> 29dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 30ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes#include <string> 31ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes 32ffdec180176094dac0fb902263370dea1deb138fElliott Hughes#include <android-base/properties.h> 33ffdec180176094dac0fb902263370dea1deb138fElliott Hughes 34dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project#include "adb.h" 35cc731cc76786b6bdc58764aad9924c0d0c8d645fDan Albert#include "adb_io.h" 365830577bd82fdb7c39555da20a4cf585b8bb376aElliott Hughes#include "adb_utils.h" 37d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg#include "fs_mgr.h" 38d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg 395677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes// Returns the device used to mount a directory in /proc/mounts. 40d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenbergstatic std::string find_proc_mount(const char* dir) { 415677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes std::unique_ptr<FILE, int(*)(FILE*)> fp(setmntent("/proc/mounts", "r"), endmntent); 425677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes if (!fp) { 435677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes return ""; 44dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project } 455677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes 465677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes mntent* e; 475677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes while ((e = getmntent(fp.get())) != nullptr) { 485677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes if (strcmp(dir, e->mnt_dir) == 0) { 495677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes return e->mnt_fsname; 50d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui } 51d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui } 525677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes return ""; 53dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project} 54dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 55d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg// Returns the device used to mount a directory in the fstab. 56d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenbergstatic std::string find_fstab_mount(const char* dir) { 57ffdec180176094dac0fb902263370dea1deb138fElliott Hughes std::string fstab_filename = "/fstab." + android::base::GetProperty("ro.hardware", ""); 58d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg struct fstab* fstab = fs_mgr_read_fstab(fstab_filename.c_str()); 59d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg struct fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab, dir); 60d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg std::string dev = rec ? std::string(rec->blk_device) : ""; 61d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg fs_mgr_free_fstab(fstab); 62d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg return dev; 63d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg} 64d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg 65d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg// The proc entry for / is full of lies, so check fstab instead. 66d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg// /proc/mounts lists rootfs and /dev/root, neither of which is what we want. 67d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenbergstatic std::string find_mount(const char* dir) { 68d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg if (strcmp(dir, "/") == 0) { 69d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg return find_fstab_mount(dir); 70d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg } else { 71d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg return find_proc_mount(dir); 72d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg } 73d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg} 74d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg 759aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughesbool make_block_device_writable(const std::string& dev) { 76ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes int fd = unix_open(dev.c_str(), O_RDONLY | O_CLOEXEC); 77ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes if (fd == -1) { 789aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes return false; 79982089d83879c768eac3fd36f19665463a550b53Paul Lawrence } 80982089d83879c768eac3fd36f19665463a550b53Paul Lawrence 81ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes int OFF = 0; 829aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes bool result = (ioctl(fd, BLKROSET, &OFF) != -1); 836ac5d7dc56a016718d2a26803435505e983e5d80Spencer Low unix_close(fd); 84ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return result; 85ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes} 866084a0124f868c7ec43f6c415a27a168f27ff694Dan Albert 879aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughesstatic bool remount_partition(int fd, const char* dir) { 889aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes if (!directory_exists(dir)) { 899aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes return true; 9013449cd71464c3a644109c469a77bd7fd56c8af8Sami Tolvanen } 919aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes std::string dev = find_mount(dir); 929aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes if (dev.empty()) { 935677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes return true; 945677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes } 959aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes if (!make_block_device_writable(dev)) { 969aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes WriteFdFmt(fd, "remount of %s failed; couldn't make block device %s writable: %s\n", 979aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes dir, dev.c_str(), strerror(errno)); 989aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes return false; 999aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes } 1009aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes if (mount(dev.c_str(), dir, "none", MS_REMOUNT, nullptr) == -1) { 1019aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes WriteFdFmt(fd, "remount of %s failed: %s\n", dir, strerror(errno)); 1025677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes return false; 1035677c23e8d0c085be8d8429a5d125147d11e9bb2Elliott Hughes } 104ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return true; 105ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes} 106ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes 107ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesvoid remount_service(int fd, void* cookie) { 108268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich if (getuid() != 0) { 109e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, "Not running as root. Try \"adb root\" first.\n"); 110268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich adb_close(fd); 111268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich return; 112268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich } 113268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich 114ffdec180176094dac0fb902263370dea1deb138fElliott Hughes bool system_verified = !(android::base::GetProperty("partition.system.verified", "").empty()); 115ffdec180176094dac0fb902263370dea1deb138fElliott Hughes bool vendor_verified = !(android::base::GetProperty("partition.vendor.verified", "").empty()); 11634637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence 11734637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence if (system_verified || vendor_verified) { 11834637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence // Allow remount but warn of likely bad effects 11934637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence bool both = system_verified && vendor_verified; 120ab52c181fa4c1c9891644635dc5653cda5b90e2bElliott Hughes WriteFdFmt(fd, 121ab52c181fa4c1c9891644635dc5653cda5b90e2bElliott Hughes "dm_verity is enabled on the %s%s%s partition%s.\n", 122ab52c181fa4c1c9891644635dc5653cda5b90e2bElliott Hughes system_verified ? "system" : "", 123ab52c181fa4c1c9891644635dc5653cda5b90e2bElliott Hughes both ? " and " : "", 124ab52c181fa4c1c9891644635dc5653cda5b90e2bElliott Hughes vendor_verified ? "vendor" : "", 125ab52c181fa4c1c9891644635dc5653cda5b90e2bElliott Hughes both ? "s" : ""); 126e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, 127e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes "Use \"adb disable-verity\" to disable verity.\n" 128e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes "If you do not, remount may succeed, however, you will still " 129e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes "not be able to write to these volumes.\n"); 13034637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence } 13134637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence 132ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes bool success = true; 133ffdec180176094dac0fb902263370dea1deb138fElliott Hughes if (android::base::GetBoolProperty("ro.build.system_root_image", false)) { 134d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg success &= remount_partition(fd, "/"); 135d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg } else { 136d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg success &= remount_partition(fd, "/system"); 137d6eba89f83a4028a4b25e44dc0f8bc59dd6ad70aDaniel Rosenberg } 1389aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes success &= remount_partition(fd, "/vendor"); 1399aa4fda4e64c1882faf019cc2a483ee4917e0c85Elliott Hughes success &= remount_partition(fd, "/oem"); 140dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 141e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, success ? "remount succeeded\n" : "remount failed\n"); 142dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 143dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project adb_close(fd); 144dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project} 145