Re: [Qemu-discuss] qemu-system-arm error when emulatting firmware

[Peter Maydell]

On 1 November 2017 at 18:31, poxyran <address@hidden> wrote:
>
>
> On 11/1/2017 1:07 PM, Peter Maydell wrote:
>> On 1 November 2017 at 13:34, poxyran <address@hidden> wrote:
>>> Hi all!,
>>>
>>> I'm trying to emulate a firmware from a DLink IP camera using
>>> qemu-system-arm but I'm facing some troubles.
>>>
>>> I'm using the following command line:
>>>
>>> address@hidden:~/QEMU/armel$ sudo qemu-system-arm -M versatilepb -kernel
>>> vmlinuz-2.6.32-5-versatile -initrd
>>> /home/fastix/dcs-942l/binary_blob.bin.swap_unpacked/initramfs.cpio -hda
>>> debian_squeeze_armel_standard.qcow2 -serial stdio -append
>>> "root=/dev/sda1 console=ttyAMA0 console=ttyS0 init=/bin/ash" -net nic
>>> -net tap

>> Otherwise if you need to run some script inside the guest
>> that assumes ttyS0 you may be able to work around it by
>> hacking around with the /dev/ files (assuming they're not
>> autocreated by udev or similar).

> I was looking around the firmware files and saw that /etc/inittab has
> the following information:
>
> ::sysinit:/etc/rc.d/rcS start
> ::respawn:/bin/sh < /dev/ttyS0 2>&1 > /dev/ttyS0
> ::restart:/sbin/init
>
> is there any way to workaround this?

(1) since you're using "init=/bin/ash" then nothing will
read /etc/inittab, so it shouldn't make a difference

(2) if you do want to run the guest init, then try
the trick I suggest above of messing with what the filesystem
has in /dev/ and/or editing inittab.

(You need to have (a) a /dev/ttysomething with the right
major/minor for the versatilepb ttyAMA0 and (b) inittab be
using that, so either (1) leave inittab as is and make /dev/ttyS0
be (a symlink to?) the right dev node, or (2) leave /dev/ttyS0
where it is, create a correct /dev/ttyAMA0 and make
inittab use that.)

thanks
-- PMM