remount_service.cpp revision e67f1f87d9b1188ec8617035db7006c37ee7b21e
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 173313426fad9eaaf53017cdbde889ebcec91358ecDan Albert#define TRACE_TAG TRACE_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 32dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project#include "adb.h" 33cc731cc76786b6bdc58764aad9924c0d0c8d645fDan Albert#include "adb_io.h" 345830577bd82fdb7c39555da20a4cf585b8bb376aElliott Hughes#include "adb_utils.h" 357664901a355b959f312e9acff5a0fd31b7139623Dan Albert#include "cutils/properties.h" 36dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 37dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Projectstatic int system_ro = 1; 38686bce6390db802bfd2cb4e78f9270596b6decb2Daniel Rosenbergstatic int vendor_ro = 1; 39ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesstatic int oem_ro = 1; 40dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 41c880ee0265a4057fd5086f4b9e8e5fae6e053087Colin Cross/* Returns the device used to mount a directory in /proc/mounts */ 42ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesstatic std::string find_mount(const char *dir) { 43d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui FILE* fp; 44d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui struct mntent* mentry; 45d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui char* device = NULL; 46dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 47d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui if ((fp = setmntent("/proc/mounts", "r")) == NULL) { 48c880ee0265a4057fd5086f4b9e8e5fae6e053087Colin Cross return NULL; 49dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project } 50d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui while ((mentry = getmntent(fp)) != NULL) { 51d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui if (strcmp(dir, mentry->mnt_dir) == 0) { 52ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes device = mentry->mnt_fsname; 53d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui break; 54d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui } 55d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui } 56d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui endmntent(fp); 57d6bd9bf45968cb97ed88a4e06c40a127625897b1Yabin Cui return device; 58dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project} 59dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 60ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesint make_block_device_writable(const std::string& dev) { 61ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes int fd = unix_open(dev.c_str(), O_RDONLY | O_CLOEXEC); 62ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes if (fd == -1) { 63ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return -1; 64982089d83879c768eac3fd36f19665463a550b53Paul Lawrence } 65982089d83879c768eac3fd36f19665463a550b53Paul Lawrence 66ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes int result = -1; 67ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes int OFF = 0; 68ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes if (!ioctl(fd, BLKROSET, &OFF)) { 69ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes result = 0; 706084a0124f868c7ec43f6c415a27a168f27ff694Dan Albert } 71ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes adb_close(fd); 726084a0124f868c7ec43f6c415a27a168f27ff694Dan Albert 73ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return result; 74ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes} 756084a0124f868c7ec43f6c415a27a168f27ff694Dan Albert 76ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes// Init mounts /system as read only, remount to enable writes. 77ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesstatic int remount(const char* dir, int* dir_ro) { 78ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes std::string dev(find_mount(dir)); 79ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes if (dev.empty() || make_block_device_writable(dev)) { 80ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return -1; 8113449cd71464c3a644109c469a77bd7fd56c8af8Sami Tolvanen } 82dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 83ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes int rc = mount(dev.c_str(), dir, "none", MS_REMOUNT, NULL); 8413449cd71464c3a644109c469a77bd7fd56c8af8Sami Tolvanen *dir_ro = rc; 856084a0124f868c7ec43f6c415a27a168f27ff694Dan Albert return rc; 8681416fdb186070fe4db3ca5fed2e713a4eecaac1Mårten Kongstad} 8781416fdb186070fe4db3ca5fed2e713a4eecaac1Mårten Kongstad 88ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesstatic bool remount_partition(int fd, const char* partition, int* ro) { 895830577bd82fdb7c39555da20a4cf585b8bb376aElliott Hughes if (!directory_exists(partition)) { 90ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return true; 91ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes } 92ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes if (remount(partition, ro)) { 93ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes char buf[200]; 94ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes snprintf(buf, sizeof(buf), "remount of %s failed: %s\n", partition, strerror(errno)); 95e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, buf); 96ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return false; 97ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes } 98ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes return true; 99ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes} 100ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes 101ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughesvoid remount_service(int fd, void* cookie) { 10234637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence char prop_buf[PROPERTY_VALUE_MAX]; 10334637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence 104268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich if (getuid() != 0) { 105e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, "Not running as root. Try \"adb root\" first.\n"); 106268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich adb_close(fd); 107268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich return; 108268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich } 109268eb4f3846d551c73eb4fc5a505f9a70d47b638Nick Kralevich 11034637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence bool system_verified = false, vendor_verified = false; 111454742392f72079dbdb0d23ea24e01b5703c1aa5Sami Tolvanen property_get("partition.system.verified", prop_buf, ""); 112454742392f72079dbdb0d23ea24e01b5703c1aa5Sami Tolvanen if (strlen(prop_buf) > 0) { 11334637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence system_verified = true; 11434637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence } 11534637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence 116454742392f72079dbdb0d23ea24e01b5703c1aa5Sami Tolvanen property_get("partition.vendor.verified", prop_buf, ""); 117454742392f72079dbdb0d23ea24e01b5703c1aa5Sami Tolvanen if (strlen(prop_buf) > 0) { 11834637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence vendor_verified = true; 11934637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence } 12034637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence 12134637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence if (system_verified || vendor_verified) { 12234637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence // Allow remount but warn of likely bad effects 12334637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence bool both = system_verified && vendor_verified; 124ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes char buffer[200]; 12534637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence snprintf(buffer, sizeof(buffer), 12634637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence "dm_verity is enabled on the %s%s%s partition%s.\n", 12734637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence system_verified ? "system" : "", 12834637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence both ? " and " : "", 12934637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence vendor_verified ? "vendor" : "", 13034637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence both ? "s" : ""); 131e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, buffer); 132e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, 133e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes "Use \"adb disable-verity\" to disable verity.\n" 134e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes "If you do not, remount may succeed, however, you will still " 135e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes "not be able to write to these volumes.\n"); 13634637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence } 13734637555c25a6663658b1ff45e98272b10b449f4Paul Lawrence 138ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes bool success = true; 139ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes success &= remount_partition(fd, "/system", &system_ro); 140ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes success &= remount_partition(fd, "/vendor", &vendor_ro); 141ec7a66713144a16361724fe88332b28bbf3f4b3cElliott Hughes success &= remount_partition(fd, "/oem", &oem_ro); 142dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 143e67f1f87d9b1188ec8617035db7006c37ee7b21eElliott Hughes WriteFdExactly(fd, success ? "remount succeeded\n" : "remount failed\n"); 144dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project 145dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project adb_close(fd); 146dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0The Android Open Source Project} 147