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/*
* 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 <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)
{
int fd;
int res;
char *token = NULL;
const char delims[] = "\n";
char buf[4096];
fd = unix_open("/proc/mounts", O_RDONLY | O_CLOEXEC);
if (fd < 0)
return NULL;
buf[sizeof(buf) - 1] = '\0';
adb_read(fd, buf, sizeof(buf) - 1);
adb_close(fd);
token = strtok(buf, delims);
while (token) {
char mount_dev[256];
char mount_dir[256];
int mount_freq;
int mount_passno;
res = sscanf(token, "%255s %255s %*s %*s %d %d\n",
mount_dev, mount_dir, &mount_freq, &mount_passno);
mount_dev[255] = 0;
mount_dir[255] = 0;
if (res == 4 && (strcmp(dir, mount_dir) == 0))
return strdup(mount_dev);
token = strtok(NULL, delims);
}
return NULL;
}
static int hasVendorPartition()
{
struct stat info;
if (!lstat("/vendor", &info))
if ((info.st_mode & S_IFMT) == S_IFDIR)
return true;
return false;
}
/* Init mounts /system as read only, remount to enable writes. */
static int remount(const char* dir, int* dir_ro)
{
char *dev;
int fd;
int OFF = 0;
if (dir_ro == 0) {
return 0;
}
dev = find_mount(dir);
if (!dev)
return -1;
fd = unix_open(dev, O_RDONLY | O_CLOEXEC);
if (fd < 0)
return -1;
ioctl(fd, BLKROSET, &OFF);
adb_close(fd);
*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));
}
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);
}
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