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/*
* Copyright (C) 2015 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 <linux/fs.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cutils/properties.h>
#include <fs_mgr.h>
#include "bootinfo.h"
using android::fs_mgr::Fstab;
using android::fs_mgr::GetEntryForMountPoint;
using android::fs_mgr::ReadDefaultFstab;
using android::fs_mgr::ReadFstabFromFile;
// Open the appropriate fstab file and fallback to /fstab.device if
// that's what's being used.
static bool open_fstab(Fstab* fstab) {
return ReadDefaultFstab(fstab) || ReadFstabFromFile("/fstab.device", fstab);
}
int boot_info_open_partition(const char* name, uint64_t* out_size, int flags) {
char* path;
int fd;
// We can't use fs_mgr to look up |name| because fstab doesn't list
// every slot partition (it uses the slotselect option to mask the
// suffix) and |slot| is expected to be of that form, e.g. boot_a.
//
// We can however assume that there's an entry for the /misc mount
// point and use that to get the device file for the misc
// partition. From there we'll assume that a by-name scheme is used
// so we can just replace the trailing "misc" by the given |name|,
// e.g.
//
// /dev/block/platform/soc.0/7824900.sdhci/by-name/misc ->
// /dev/block/platform/soc.0/7824900.sdhci/by-name/boot_a
//
// If needed, it's possible to relax this assumption in the future
// by trawling /sys/block looking for the appropriate sibling of
// misc and then finding an entry in /dev matching the sysfs entry.
Fstab fstab;
if (!open_fstab(&fstab)) {
return -1;
}
auto record = GetEntryForMountPoint(&fstab, "/misc");
if (record == nullptr) {
return -1;
}
if (strcmp(name, "misc") == 0) {
path = strdup(record->blk_device.c_str());
} else {
size_t trimmed_len, name_len;
const char* end_slash = strrchr(record->blk_device.c_str(), '/');
if (end_slash == NULL) {
return -1;
}
trimmed_len = end_slash - record->blk_device.c_str() + 1;
name_len = strlen(name);
path = static_cast<char*>(calloc(trimmed_len + name_len + 1, 1));
strncpy(path, record->blk_device.c_str(), trimmed_len);
strncpy(path + trimmed_len, name, name_len);
}
fd = open(path, flags);
free(path);
// If we successfully opened the device, get size if requested.
if (fd != -1 && out_size != NULL) {
if (ioctl(fd, BLKGETSIZE64, out_size) != 0) {
close(fd);
return -1;
}
}
return fd;
}
// As per struct bootloader_message_ab which is defined in
// boot/1.1/default.
// struct bootloader_message_ab {
// struct bootloader_message message;
// char slot_suffix[32];
// char update_channel[128];
//
// // Round up the entire struct to 4096-byte.
// char reserved[1888];
// };
//
// We can use the 32 bytes in the bootctrl_suffix field provided that they
// start with the active slot suffix terminated by NUL. It just so happens
// that BrilloBootInfo is laid out this way.
#define BOOTINFO_OFFSET 2048
bool boot_info_load(BrilloBootInfo* out_info) {
int fd;
memset(out_info, '\0', sizeof(BrilloBootInfo));
fd = boot_info_open_partition("misc", NULL, O_RDONLY);
if (fd == -1) return false;
if (lseek(fd, BOOTINFO_OFFSET, SEEK_SET) != BOOTINFO_OFFSET) {
close(fd);
return false;
}
ssize_t num_read;
do {
num_read = read(fd, (void*)out_info, sizeof(BrilloBootInfo));
} while (num_read == -1 && errno == EINTR);
close(fd);
if (num_read != sizeof(BrilloBootInfo)) return false;
return true;
}
bool boot_info_save(BrilloBootInfo* info) {
int fd;
fd = boot_info_open_partition("misc", NULL, O_RDWR);
if (fd == -1) return false;
if (lseek(fd, BOOTINFO_OFFSET, SEEK_SET) != BOOTINFO_OFFSET) {
close(fd);
return false;
}
ssize_t num_written;
do {
num_written = write(fd, (void*)info, sizeof(BrilloBootInfo));
} while (num_written == -1 && errno == EINTR);
close(fd);
if (num_written != sizeof(BrilloBootInfo)) return false;
return true;
}
bool boot_info_validate(BrilloBootInfo* info) {
if (info->magic[0] != 'B' || info->magic[1] != 'C' || info->magic[2] != 'c') return false;
if (info->active_slot >= 2) return false;
return true;
}
void boot_info_reset(BrilloBootInfo* info) {
memset(info, '\0', sizeof(BrilloBootInfo));
info->magic[0] = 'B';
info->magic[1] = 'C';
info->magic[2] = 'c';
}
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