merge from open-source master

static int system_ro = 1;

/* Returns the mount number of the requested partition from /proc/mtd */

static int find_mount(const char *findme)

/* Returns the device used to mount a directory in /proc/mounts */

static char *find_mount(const char *dir)

{

    int fd;

    int res;

    int size;

    char *token = NULL;

    const char delims[] = "\n";

    char buf[1024];

    char buf[4096];

    fd = unix_open("/proc/mtd", O_RDONLY);

    fd = unix_open("/proc/mounts", O_RDONLY);

    if (fd < 0)

        return -errno;

        return NULL;

    buf[sizeof(buf) - 1] = '\0';

    size = adb_read(fd, buf, sizeof(buf) - 1);

    token = strtok(buf, delims);

    while (token) {

        char mtdname[16];

        int mtdnum, mtdsize, mtderasesize;

        res = sscanf(token, "mtd%d: %x %x %15s",

                     &mtdnum, &mtdsize, &mtderasesize, mtdname);

        if (res == 4 && !strcmp(mtdname, findme))

            return mtdnum;

        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 -1;

    return NULL;

}

/* Init mounts /system as read only, remount to enable writes. */

static int remount_system()

{

    int num;

    char source[64];

    char *dev;

    if (system_ro == 0) {

        return 0;

    }

    if ((num = find_mount("\"system\"")) < 0)

    dev = find_mount("/system");

    if (!dev)

        return -1;

    snprintf(source, sizeof source, "/dev/block/mtdblock%d", num);

    system_ro = mount(source, "/system", "yaffs2", MS_REMOUNT, NULL);

    system_ro = mount(dev, "/system", "none", MS_REMOUNT, NULL);

    free(dev);

    return system_ro;

}