bootloader.c

/*
 * 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 "bootloader.h"
#include "common.h"
#include "mtdutils/mtdutils.h"
#include "roots.h"

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

static int get_bootloader_message_mtd(struct bootloader_message *out, const Volume* v);
static int set_bootloader_message_mtd(const struct bootloader_message *in, const Volume* v);
static int get_bootloader_message_block(struct bootloader_message *out, const Volume* v);
static int set_bootloader_message_block(const struct bootloader_message *in, const Volume* v);

int get_bootloader_message(struct bootloader_message *out) {
    Volume* v = volume_for_path("/misc");
    if(v)
    {
        if (strcmp(v->fs_type, "mtd") == 0) {
                return get_bootloader_message_mtd(out, v);
        } else if (strcmp(v->fs_type, "emmc") == 0) {
                return get_bootloader_message_block(out, v);
        }
        LOGE("unknown misc partition fs_type \"%s\"\n", v->fs_type);
        return -1;
    }
    return -1;
}

int set_bootloader_message(const struct bootloader_message *in) {
    Volume* v = volume_for_path("/misc");
    if(v)
    {
        if (strcmp(v->fs_type, "mtd") == 0) {
            return set_bootloader_message_mtd(in, v);
        } else if (strcmp(v->fs_type, "emmc") == 0) {
            return set_bootloader_message_block(in, v);
        }
        LOGE("unknown misc partition fs_type \"%s\"\n", v->fs_type);
        return -1;
    }
    return -1;
}

// ------------------------------
// for misc partitions on MTD
// ------------------------------

static const int MISC_PAGES = 3;         // number of pages to save
static const int MISC_COMMAND_PAGE = 1;  // bootloader command is this page

static int get_bootloader_message_mtd(struct bootloader_message *out,
                                      const Volume* v) {
    size_t write_size;
    mtd_scan_partitions();
    const MtdPartition *part = mtd_find_partition_by_name(v->device);
    if (part == NULL || mtd_partition_info(part, NULL, NULL, &write_size)) {
        LOGE("Can't find %s\n", v->device);
        return -1;
    }

    MtdReadContext *read = mtd_read_partition(part);
    if (read == NULL) {
        LOGE("Can't open %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }

    const ssize_t size = write_size * MISC_PAGES;
    char data[size];
    ssize_t r = mtd_read_data(read, data, size);
    if (r != size) LOGE("Can't read %s\n(%s)\n", v->device, strerror(errno));
    mtd_read_close(read);
    if (r != size) return -1;

    memcpy(out, &data[write_size * MISC_COMMAND_PAGE], sizeof(*out));
    return 0;
}
static int set_bootloader_message_mtd(const struct bootloader_message *in,
                                      const Volume* v) {
    size_t write_size;
    mtd_scan_partitions();
    const MtdPartition *part = mtd_find_partition_by_name(v->device);
    if (part == NULL || mtd_partition_info(part, NULL, NULL, &write_size)) {
        LOGE("Can't find %s\n", v->device);
        return -1;
    }

    MtdReadContext *read = mtd_read_partition(part);
    if (read == NULL) {
        LOGE("Can't open %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }

    ssize_t size = write_size * MISC_PAGES;
    char data[size];
    ssize_t r = mtd_read_data(read, data, size);
    if (r != size) LOGE("Can't read %s\n(%s)\n", v->device, strerror(errno));
    mtd_read_close(read);
    if (r != size) return -1;

    memcpy(&data[write_size * MISC_COMMAND_PAGE], in, sizeof(*in));

    MtdWriteContext *write = mtd_write_partition(part);
    if (write == NULL) {
        LOGE("Can't open %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    if (mtd_write_data(write, data, size) != size) {
        LOGE("Can't write %s\n(%s)\n", v->device, strerror(errno));
        mtd_write_close(write);
        return -1;
    }
    if (mtd_write_close(write)) {
        LOGE("Can't finish %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }

    LOGI("Set boot command \"%s\"\n", in->command[0] != 255 ? in->command : "");
    return 0;
}


// ------------------------------------
// for misc partitions on block devices
// ------------------------------------

static void wait_for_device(const char* fn) {
    int tries = 0;
    int ret;
    struct stat buf;
    do {
        ++tries;
        ret = stat(fn, &buf);
        if (ret) {
            printf("stat %s try %d: %s\n", fn, tries, strerror(errno));
            sleep(1);
        }
    } while (ret && tries < 10);
    if (ret) {
        printf("failed to stat %s\n", fn);
    }
}

static int get_bootloader_message_block(struct bootloader_message *out,
                                        const Volume* v) {
    wait_for_device(v->device);
    FILE* f = fopen(v->device, "rb");
    if (f == NULL) {
        LOGE("Can't open %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    struct bootloader_message temp;
    int count = fread(&temp, sizeof(temp), 1, f);
    if (count != 1) {
        LOGE("Failed reading %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    if (fclose(f) != 0) {
        LOGE("Failed closing %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    memcpy(out, &temp, sizeof(temp));
    return 0;
}

static int set_bootloader_message_block(const struct bootloader_message *in,
                                        const Volume* v) {
    wait_for_device(v->device);
    FILE* f = fopen(v->device, "wb");
    if (f == NULL) {
        LOGE("Can't open %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    int count = fwrite(in, sizeof(*in), 1, f);
    if (count != 1) {
        LOGE("Failed writing %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    if (fclose(f) != 0) {
        LOGE("Failed closing %s\n(%s)\n", v->device, strerror(errno));
        return -1;
    }
    return 0;
}

/* Update Image
 *
 * - will be stored in the "cache" partition
 * - bad blocks will be ignored, like boot.img and recovery.img
 * - the first block will be the image header (described below)
 * - the size is in BYTES, inclusive of the header
 * - offsets are in BYTES from the start of the update header
 * - two raw bitmaps will be included, the "busy" and "fail" bitmaps
 * - for dream, the bitmaps will be 320x480x16bpp RGB565
 */
 
#define UPDATE_MAGIC       "MSM-RADIO-UPDATE"
#define UPDATE_MAGIC_SIZE  16
#define UPDATE_VERSION     0x00010000
 
struct update_header {
    unsigned char MAGIC[UPDATE_MAGIC_SIZE];
 
    unsigned version;
    unsigned size;
 
    unsigned image_offset;
    unsigned image_length;
 
    unsigned bitmap_width;
    unsigned bitmap_height;
    unsigned bitmap_bpp;
 
    unsigned busy_bitmap_offset;
    unsigned busy_bitmap_length;
 
    unsigned fail_bitmap_offset;
    unsigned fail_bitmap_length;
};

int write_update_for_bootloader(
        const char *update, int update_length,
        int bitmap_width, int bitmap_height, int bitmap_bpp,
        const char *busy_bitmap, const char *fail_bitmap) {
    if (ensure_path_unmounted("/cache")) {
        LOGE("Can't unmount /cache\n");
        return -1;
    }
 
    const MtdPartition *part = mtd_find_partition_by_name("cache");
    if (part == NULL) {
        LOGE("Can't find cache\n");
        return -1;
    }
 
    MtdWriteContext *write = mtd_write_partition(part);
    if (write == NULL) {
        LOGE("Can't open cache\n(%s)\n", strerror(errno));
        return -1;
    }
 
    /* Write an invalid (zero) header first, to disable any previous
     * update and any other structured contents (like a filesystem),
     * and as a placeholder for the amount of space required.
     */
 
    struct update_header header;
    memset(&header, 0, sizeof(header));
    const ssize_t header_size = sizeof(header);
    if (mtd_write_data(write, (char*) &header, header_size) != header_size) {
        LOGE("Can't write header to cache\n(%s)\n", strerror(errno));
        mtd_write_close(write);
        return -1;
    }
 
    /* Write each section individually block-aligned, so we can write
     * each block independently without complicated buffering.
     */
 
    memcpy(&header.MAGIC, UPDATE_MAGIC, UPDATE_MAGIC_SIZE);
    header.version = UPDATE_VERSION;
    header.size = header_size;
 
    off_t image_start_pos = mtd_erase_blocks(write, 0);
    header.image_length = update_length;
    if ((int) header.image_offset == -1 ||
        mtd_write_data(write, update, update_length) != update_length) {
        LOGE("Can't write update to cache\n(%s)\n", strerror(errno));
        mtd_write_close(write);
        return -1;
    }
    off_t busy_start_pos = mtd_erase_blocks(write, 0);
    header.image_offset = mtd_find_write_start(write, image_start_pos);
 
    header.bitmap_width = bitmap_width;
    header.bitmap_height = bitmap_height;
    header.bitmap_bpp = bitmap_bpp;
 
    int bitmap_length = (bitmap_bpp + 7) / 8 * bitmap_width * bitmap_height;
 
    header.busy_bitmap_length = busy_bitmap != NULL ? bitmap_length : 0;
    if ((int) header.busy_bitmap_offset == -1 ||
        mtd_write_data(write, busy_bitmap, bitmap_length) != bitmap_length) {
        LOGE("Can't write bitmap to cache\n(%s)\n", strerror(errno));
        mtd_write_close(write);
        return -1;
    }
    off_t fail_start_pos = mtd_erase_blocks(write, 0);
    header.busy_bitmap_offset = mtd_find_write_start(write, busy_start_pos);
 
    header.fail_bitmap_length = fail_bitmap != NULL ? bitmap_length : 0;
    if ((int) header.fail_bitmap_offset == -1 ||
        mtd_write_data(write, fail_bitmap, bitmap_length) != bitmap_length) {
        LOGE("Can't write bitmap to cache\n(%s)\n", strerror(errno));
        mtd_write_close(write);
        return -1;
    }
    mtd_erase_blocks(write, 0);
    header.fail_bitmap_offset = mtd_find_write_start(write, fail_start_pos);
 
    /* Write the header last, after all the blocks it refers to, so that
     * when the magic number is installed everything is valid.
     */
 
    if (mtd_write_close(write)) {
        LOGE("Can't finish writing cache\n(%s)\n", strerror(errno));
        return -1;
    }
 
    write = mtd_write_partition(part);
    if (write == NULL) {
        LOGE("Can't reopen cache\n(%s)\n", strerror(errno));
        return -1;
    }
 
    if (mtd_write_data(write, (char*) &header, header_size) != header_size) {
        LOGE("Can't rewrite header to cache\n(%s)\n", strerror(errno));
        mtd_write_close(write);
        return -1;
    }
 
    if (mtd_erase_blocks(write, 0) != image_start_pos) {
        LOGE("Misalignment rewriting cache\n(%s)\n", strerror(errno));
        mtd_write_close(write);
        return -1;
    }
 
    if (mtd_write_close(write)) {
        LOGE("Can't finish header of cache\n(%s)\n", strerror(errno));
        return -1;
    }
 
    return 0;
}