170 lines
4.1 KiB
C
170 lines
4.1 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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#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 "cutils/properties.h"
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#define TRACE_TAG TRACE_ADB
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#include "adb.h"
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static int system_ro = 1;
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static int vendor_ro = 1;
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/* Returns the device used to mount a directory in /proc/mounts */
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static char *find_mount(const char *dir)
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{
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FILE* fp;
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struct mntent* mentry;
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char* device = NULL;
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if ((fp = setmntent("/proc/mounts", "r")) == NULL) {
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return NULL;
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}
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while ((mentry = getmntent(fp)) != NULL) {
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if (strcmp(dir, mentry->mnt_dir) == 0) {
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device = strdup(mentry->mnt_fsname);
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break;
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}
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}
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endmntent(fp);
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return device;
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}
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static int hasVendorPartition()
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{
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struct stat info;
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if (!lstat("/vendor", &info))
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if ((info.st_mode & S_IFMT) == S_IFDIR)
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return true;
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return false;
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}
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int make_block_device_writable(const char* dev)
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{
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int fd = -1;
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int OFF = 0;
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int rc = -1;
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if (!dev)
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goto errout;
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fd = unix_open(dev, O_RDONLY | O_CLOEXEC);
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if (fd < 0)
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goto errout;
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if (ioctl(fd, BLKROSET, &OFF)) {
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goto errout;
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}
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rc = 0;
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errout:
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if (fd >= 0) {
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adb_close(fd);
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}
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return rc;
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}
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/* Init mounts /system as read only, remount to enable writes. */
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static int remount(const char* dir, int* dir_ro)
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{
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char *dev = 0;
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int rc = -1;
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dev = find_mount(dir);
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if (!dev || make_block_device_writable(dev)) {
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goto errout;
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}
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rc = mount(dev, dir, "none", MS_REMOUNT, NULL);
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*dir_ro = rc;
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errout:
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free(dev);
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return rc;
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}
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static void write_string(int fd, const char* str)
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{
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writex(fd, str, strlen(str));
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}
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void remount_service(int fd, void *cookie)
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{
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char buffer[200];
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char prop_buf[PROPERTY_VALUE_MAX];
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bool system_verified = false, vendor_verified = false;
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property_get("partition.system.verified", prop_buf, "0");
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if (!strcmp(prop_buf, "1")) {
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system_verified = true;
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}
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property_get("partition.vendor.verified", prop_buf, "0");
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if (!strcmp(prop_buf, "1")) {
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vendor_verified = true;
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}
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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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snprintf(buffer, sizeof(buffer),
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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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write_string(fd, buffer);
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snprintf(buffer, sizeof(buffer),
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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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write_string(fd, buffer);
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}
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if (remount("/system", &system_ro)) {
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snprintf(buffer, sizeof(buffer), "remount of system failed: %s\n",strerror(errno));
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write_string(fd, buffer);
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}
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if (hasVendorPartition()) {
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if (remount("/vendor", &vendor_ro)) {
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snprintf(buffer, sizeof(buffer), "remount of vendor failed: %s\n",strerror(errno));
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write_string(fd, buffer);
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}
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}
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if (!system_ro && (!vendor_ro || !hasVendorPartition()))
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write_string(fd, "remount succeeded\n");
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else {
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write_string(fd, "remount failed\n");
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}
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adb_close(fd);
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}
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