How to verify the android 9 system verity and mount the rootfs(actually the system.img)?

[andrew wu]

Dears,

I'm studying the android 9.0 ramdisk mechanism

system-as-root is mandatory on android 9.0.

Assume:

1.use android9.0 + Kernel-4.4

2.system-as-root is enabled

3.here is a non-A/B scenario

Checking the soruce code:

static int __init populate_rootfs(void)

{

char *err;

if (do_skip_initramfs) {

if (initrd_start)

free_initrd();

return default_rootfs();

}

err = unpack_to_rootfs(__initramfs_start, __initramfs_size);

......

}

because the do_skip_initramfs  is true and initrd_start is 0, just default_rootfs is called.

Where is the system.img is verified and mounted? Do somewhere has the detail flow process?

waiting for your good voice.

BestRegards

Andrew

2019.1.24