153 lines
4.6 KiB
C++
153 lines
4.6 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define TRACE_TAG ADB
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#include "sysdeps.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <mntent.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mount.h>
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#include <unistd.h>
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#include <string>
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#include "adb.h"
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#include "adb_io.h"
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#include "adb_utils.h"
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#include "cutils/properties.h"
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#include "fs_mgr.h"
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// Returns the device used to mount a directory in /proc/mounts.
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static std::string find_proc_mount(const char* dir) {
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std::unique_ptr<FILE, int(*)(FILE*)> fp(setmntent("/proc/mounts", "r"), endmntent);
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if (!fp) {
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return "";
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}
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mntent* e;
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while ((e = getmntent(fp.get())) != nullptr) {
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if (strcmp(dir, e->mnt_dir) == 0) {
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return e->mnt_fsname;
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}
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}
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return "";
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}
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// Returns the device used to mount a directory in the fstab.
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static std::string find_fstab_mount(const char* dir) {
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char propbuf[PROPERTY_VALUE_MAX];
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property_get("ro.hardware", propbuf, "");
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std::string fstab_filename = std::string("/fstab.") + propbuf;
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struct fstab* fstab = fs_mgr_read_fstab(fstab_filename.c_str());
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struct fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab, dir);
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std::string dev = rec ? std::string(rec->blk_device) : "";
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fs_mgr_free_fstab(fstab);
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return dev;
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}
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// The proc entry for / is full of lies, so check fstab instead.
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// /proc/mounts lists rootfs and /dev/root, neither of which is what we want.
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static std::string find_mount(const char* dir) {
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if (strcmp(dir, "/") == 0) {
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return find_fstab_mount(dir);
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} else {
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return find_proc_mount(dir);
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}
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}
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bool make_block_device_writable(const std::string& dev) {
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int fd = unix_open(dev.c_str(), O_RDONLY | O_CLOEXEC);
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if (fd == -1) {
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return false;
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}
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int OFF = 0;
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bool result = (ioctl(fd, BLKROSET, &OFF) != -1);
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unix_close(fd);
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return result;
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}
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static bool remount_partition(int fd, const char* dir) {
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if (!directory_exists(dir)) {
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return true;
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}
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std::string dev = find_mount(dir);
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if (dev.empty()) {
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return true;
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}
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if (!make_block_device_writable(dev)) {
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WriteFdFmt(fd, "remount of %s failed; couldn't make block device %s writable: %s\n",
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dir, dev.c_str(), strerror(errno));
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return false;
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}
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if (mount(dev.c_str(), dir, "none", MS_REMOUNT, nullptr) == -1) {
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WriteFdFmt(fd, "remount of %s failed: %s\n", dir, strerror(errno));
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return false;
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}
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return true;
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}
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void remount_service(int fd, void* cookie) {
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if (getuid() != 0) {
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WriteFdExactly(fd, "Not running as root. Try \"adb root\" first.\n");
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adb_close(fd);
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return;
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}
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char prop_buf[PROPERTY_VALUE_MAX];
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property_get("partition.system.verified", prop_buf, "");
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bool system_verified = (strlen(prop_buf) > 0);
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property_get("partition.vendor.verified", prop_buf, "");
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bool vendor_verified = (strlen(prop_buf) > 0);
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if (system_verified || vendor_verified) {
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// Allow remount but warn of likely bad effects
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bool both = system_verified && vendor_verified;
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WriteFdFmt(fd,
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"dm_verity is enabled on the %s%s%s partition%s.\n",
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system_verified ? "system" : "",
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both ? " and " : "",
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vendor_verified ? "vendor" : "",
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both ? "s" : "");
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WriteFdExactly(fd,
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"Use \"adb disable-verity\" to disable verity.\n"
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"If you do not, remount may succeed, however, you will still "
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"not be able to write to these volumes.\n");
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}
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bool success = true;
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property_get("ro.build.system_root_image", prop_buf, "");
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bool system_root = !strcmp(prop_buf, "true");
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if (system_root) {
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success &= remount_partition(fd, "/");
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} else {
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success &= remount_partition(fd, "/system");
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}
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success &= remount_partition(fd, "/vendor");
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success &= remount_partition(fd, "/oem");
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WriteFdExactly(fd, success ? "remount succeeded\n" : "remount failed\n");
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adb_close(fd);
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}
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