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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 <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <unistd.h>
#include "sysdeps.h"
#define TRACE_TAG TRACE_ADB
#include "adb.h"
static int system_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;
}
/* Init mounts /system as read only, remount to enable writes. */
static int remount_system()
{
char *dev;
int fd;
int OFF = 0;
if (system_ro == 0) {
return 0;
}
dev = find_mount("/system");
if (!dev)
return -1;
fd = unix_open(dev, O_RDONLY | O_CLOEXEC);
if (fd < 0)
return -1;
ioctl(fd, BLKROSET, &OFF);
adb_close(fd);
system_ro = mount(dev, "/system", "none", MS_REMOUNT, NULL);
free(dev);
return system_ro;
}
static void write_string(int fd, const char* str)
{
writex(fd, str, strlen(str));
}
void remount_service(int fd, void *cookie)
{
int ret = remount_system();
if (!ret)
write_string(fd, "remount succeeded\n");
else {
char buffer[200];
snprintf(buffer, sizeof(buffer), "remount failed: %s\n", strerror(errno));
write_string(fd, buffer);
}
adb_close(fd);
}
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