restore.cpp

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/vfs.h>

#include <cutils/properties.h>

#include <lib/libtar.h>
#include <zlib.h>

#include <fs_mgr.h>
#include "roots.h"

#include "bu.h"

using namespace android;

static int verify_sod()
{
    const char* key;
    char value[PROPERTY_VALUE_MAX];
    char sodbuf[PROP_LINE_LEN*10];
    size_t len;

    len = sizeof(sodbuf);
    if (tar_extract_file_contents(tar, sodbuf, &len) != 0) {
        logmsg("tar_verify_sod: failed to extract file\n");
        return -1;
    }

    int partidx = 0;

    char val_hashname[PROPERTY_VALUE_MAX];
    memset(val_hashname, 0, sizeof(val_hashname));
    char val_product[PROPERTY_VALUE_MAX];
    memset(val_product, 0, sizeof(val_product));
    char* p = sodbuf;
    char* q;
    while ((q = strchr(p, '\n')) != NULL) {
        char* key = p;
        *q = '\0';
        logmsg("verify_sod: line=%s\n", p);
        p = q+1;
        char* val = strchr(key, '=');
        if (val) {
            *val = '\0';
            ++val;
            if (strcmp(key, "hash.name") == 0) {
                strncpy(val_hashname, val, sizeof(val_hashname));
            }
            if (strcmp(key, "ro.product.device") == 0) {
                strncpy(val_product, val, sizeof(val_product));
            }
            if (strncmp(key, "fs.", 3) == 0) {
                char* name = key+3;
                char* attr = strchr(name, '.');
                if (attr) {
                    *attr = '\0';
                    ++attr;
                    part_add(name);
                    struct partspec* part = part_find(name);
                    if (!strcmp(attr, "size")) {
                        part->size = strtoul(val, NULL, 0);
                    }
                    if (!strcmp(attr, "used")) {
                        part->used = strtoul(val, NULL, 0);
                    }
                }
            }
        }
    }

    if (!val_hashname[0]) {
        logmsg("verify_sod: did not find hash.name\n");
        return -1;
    }
    hash_name = strdup(val_hashname);

    if (!val_product[0]) {
        logmsg("verify_sod: did not find ro.product.device\n");
        return -1;
    }
    key = "ro.product.device";
    property_get(key, value, "");
    if (strcmp(val_product, value) != 0) {
        logmsg("verify_sod: product does not match\n");
        return -1;
    }

    return 0;
}

static int verify_eod(size_t actual_hash_datalen,
        SHA_CTX* actual_sha_ctx, MD5_CTX* actual_md5_ctx)
{
    int rc = -1;
    char eodbuf[PROP_LINE_LEN*10];
    size_t len;

    len = sizeof(eodbuf);
    if (tar_extract_file_contents(tar, eodbuf, &len) != 0) {
        logmsg("verify_eod: failed to extract file\n");
        return -1;
    }

    size_t reported_datalen = 0;
    char reported_hash[HASH_MAX_STRING_LENGTH];
    memset(reported_hash, 0, sizeof(reported_hash));
    char* p = eodbuf;
    char* q;
    while ((q = strchr(p, '\n')) != NULL) {
        char* key = p;
        *q = '\0';
        logmsg("verify_eod: line=%s\n", p);
        p = q+1;
        char* val = strchr(key, '=');
        if (val) {
            *val = '\0';
            ++val;
            if (strcmp(key, "hash.datalen") == 0) {
                reported_datalen = strtoul(val, NULL, 0);
            }
            if (strcmp(key, "hash.value") == 0) {
                memset(reported_hash, 0, sizeof(reported_hash));
                strncpy(reported_hash, val, sizeof(reported_hash));
            }
        }
    }

    unsigned char digest[HASH_MAX_LENGTH];
    char hexdigest[HASH_MAX_STRING_LENGTH];

    int n;
    if (hash_name != NULL && !strcasecmp(hash_name, "sha1")) {
        SHA1_Final(digest, actual_sha_ctx);
         for (n = 0; n < SHA_DIGEST_LENGTH; ++n) {
             sprintf(hexdigest+2*n, "%02x", digest[n]);
         }
    }
    else { // default to md5
        MD5_Final(digest, actual_md5_ctx);
        for (n = 0; n < MD5_DIGEST_LENGTH; ++n) {
            sprintf(hexdigest+2*n, "%02x", digest[n]);
        }
    }

    logmsg("verify_eod: expected=%d,%s\n", actual_hash_datalen, hexdigest);

    logmsg("verify_eod: reported=%d,%s\n", reported_datalen, reported_hash);

    if ((reported_datalen == actual_hash_datalen) &&
            (memcmp(hexdigest, reported_hash, strlen(hexdigest)) == 0)) {
        rc = 0;
    }

    return rc;
}

static int do_restore_tree()
{
    int rc = 0;
    ssize_t len;
    const char* compress = "none";
    char buf[512];
    char rootpath[] = "/";

    logmsg("do_restore_tree: enter\n");

    len = recv(adb_ifd, buf, sizeof(buf), MSG_PEEK);
    if (len < 0) {
        logmsg("do_restore_tree: peek failed (%d:%s)\n", rc, strerror(errno));
        return -1;
    }
    if (len < 2) {
        logmsg("do_restore_tree: peek returned %d\n", len);
        return -1;
    }
    if (buf[0] == 0x1f && buf[1] == 0x8b) {
        logmsg("do_restore_tree: is gzip\n");
        compress = "gzip";
    }

    create_tar(adb_ifd, compress, "r");

    size_t save_hash_datalen;
    SHA_CTX save_sha_ctx;
    MD5_CTX save_md5_ctx;

    char cur_mount[PATH_MAX];
    cur_mount[0] = '\0';
    while (1) {
        save_hash_datalen = hash_datalen;
        memcpy(&save_sha_ctx, &sha_ctx, sizeof(SHA_CTX));
        memcpy(&save_md5_ctx, &md5_ctx, sizeof(MD5_CTX));
        rc = th_read(tar);
        if (rc != 0) {
            if (rc == 1) { // EOF
                rc = 0;
            }
            break;
        }
        char* pathname = th_get_pathname(tar);
        logmsg("do_restore_tree: extract %s\n", pathname);
        if (pathname[0] == '/') {
            const char* mntend = strchr(&pathname[1], '/');
            if (!mntend) {
                mntend = pathname + strlen(pathname);
            }
            if (memcmp(cur_mount, pathname, mntend-pathname) != 0) {
                // New mount
                if (cur_mount[0]) {
                    logmsg("do_restore_tree: unmounting %s\n", cur_mount);
                    ensure_path_unmounted(cur_mount);
                }
                memcpy(cur_mount, pathname, mntend-pathname);
                cur_mount[mntend-pathname] = '\0';

                // XXX: Assume paths are not interspersed
                logmsg("do_restore_tree: switching to %s\n", cur_mount);
                rc = ensure_path_unmounted(cur_mount);
                if (rc != 0) {
                    logmsg("do_restore_tree: cannot unmount %s\n", cur_mount);
                    break;
                }
                logmsg("do_restore_tree: formatting %s\n", cur_mount);
                rc = format_volume(cur_mount);
                if (rc != 0) {
                    logmsg("do_restore_tree: cannot format %s\n", cur_mount);
                    break;
                }
                rc = ensure_path_mounted(cur_mount, true);
                if (rc != 0) {
                    logmsg("do_restore_tree: cannot mount %s\n", cur_mount);
                    break;
                }
                partspec* curpart = part_find(&cur_mount[1]);
                part_set(curpart);
            }
            rc = tar_extract_file(tar, pathname);
            if (rc != 0) {
                logmsg("do_restore_tree: failed to restore %s", pathname);
            }
        }
        else if (!strcmp(pathname, "SOD")) {
            rc = verify_sod();
            logmsg("do_restore_tree: tar_verify_sod returned %d\n", rc);
        }
        else if (!strcmp(pathname, "EOD")) {
            rc = verify_eod(save_hash_datalen, &save_sha_ctx, &save_md5_ctx);
            logmsg("do_restore_tree: tar_verify_eod returned %d\n", rc);
        }
        else {
            char mnt[PATH_MAX];
            snprintf(mnt, sizeof(mnt), "/%s", pathname);
            Volume* vol = volume_for_path(mnt);
            if (vol != NULL && vol->fs_type != NULL) {
                partspec* curpart = part_find(pathname);
                part_set(curpart);
                rc = tar_extract_file(tar, vol->blk_device);
            }
            else {
                logmsg("do_restore_tree: cannot find volume for %s\n", mnt);
            }
        }
        free(pathname);
        if (rc != 0) {
            logmsg("extract failed, rc=%d\n", rc);
            break;
        }
    }

    if (cur_mount[0]) {
        logmsg("do_restore_tree: unmounting %s\n", cur_mount);
        ensure_path_unmounted(cur_mount);
    }

    tar_close(tar);

    return rc;
}

int do_restore(int argc, char **argv)
{
    int rc = 1;
    int n;

    char buf[256];
    int len;
    int written;

    rc = do_restore_tree();
    logmsg("do_restore: rc=%d\n", rc);

    free(hash_name);
    hash_name = NULL;

    return rc;
}