On May 26, 2023 2:00:00 PM GMT+02:00, "Flávio Cruz" <flaviocruz@gmail.com> wrote:
>Hi Sergey
>
>On Fri, May 19, 2023 at 4:02 AM Sergey Bugaev <bugaevc@gmail.com> wrote:
>
>> Hi,
>>
>> On Fri, May 19, 2023 at 9:43 AM Flávio Cruz <flaviocruz@gmail.com> wrote:
>> > I have made changes so that it does daily builds and I'm able to boot
>> small programs. However, I haven't had the time to boot programs built
>> against Glibc. How do you package and boot the static binaries using a
>> ramdisk? I've been reading the other threads about the Guix/rumpkernel so I
>> might be able to piece something together and try it this weekend.
>>
>> You just put the entirety of the root filesystem (containing /usr,
>> /bin, /lib, /hurd, and so on) as an ext2 image into a *file* that you
>> place onto the actual drive (a CD disk in my case), and then you ask
>> GRUB to load the file from the drive into memory, tell gnumach to make
>> a ramdisk device out of it (you'll need to apply [0]), and tell ext2fs
>> to use that device. Here's the relevant piece of my grub config
>> script:
>>
>> [0]:
>> https://salsa.debian.org/hurd-team/gnumach/-/blob/master/debian/patches/50_initrd.patch
>>
>> multiboot /boot/gnumach console=com0
>> module /boot/initrd.ext2 initrd.ext2 '$(ramdisk-create)'
>> module /sbin/ext2fs.static ext2fs
>> --multiboot-command-line='${kernel-command-line}' --readonly
>> --host-priv-port='${host-port}' --device-master-port='${device-port}'
>> --exec-server-task='${exec-task}' --kernel-task='${kernel-task}' -T
>> device rd0 '$(fs-task=task-create)' '$(prompt-task-resume)'
>> module /lib/ld.so.1 ld.so.1 /hurd/exec
>> --device-master-port='${device-port}' '$(exec-task=task-create)'
>> boot
>>
>> (I should probably change it to not hardcode 'rd0', but whatever).
>> Note that /boot/gnumach, /boot/initrd.ext2, /sbin/ext2fs.static, and
>> /lib/ld.so.1 are all paths inside the CD image (those are going to be
>> loaded by GRUB), and /boot/initrd.ext2 is the ext2 filesystem image
>> containing the actual Hurd root. /hurd/exec however is already a path
>> inside the fs image -- this is where ld.so (not grub) is going to load
>> the exec server from. The only static binary here is ext2fs.static,
>> the rest are all dynamically linked.
>>
>> Then in /libexec/console-run (inside the filesystem image), I have
>> written the following:
>>
>> #! /bin/sh
>>
>> settrans -ac /dev/mach-console /hurd/streamio console
>> exec <>/dev/mach-console >&0 2>&0
>> echo Hello from /bin/sh!
>> exec /bin/sh -i
>>
>> (If you're going to do the same, don't forget to create the
>> /dev/mach-console node beforehand, since the fs is read-only.) I also
>> had to patch streamio a little to do the \r -> \n conversion like
>> glibc already does in devstream:
>>
>> diff --git a/trans/streamio.c b/trans/streamio.c
>> index 272a002c..0af1aea3 100644
>> --- a/trans/streamio.c
>> +++ b/trans/streamio.c
>> @@ -500,6 +500,9 @@ trivfs_S_io_read (struct trivfs_protid *cred,
>> cred->po->openmodes & O_NONBLOCK);
>> pthread_mutex_unlock (&global_lock);
>> *data_len = data_size;
>> + for (size_t i = 0; i < data_size; i++)
>> + if ((*data)[i] == '\r')
>> + (*data)[i] = '\n';
>> return err;
>> }
>>
>> (maybe I should also add echoing of input characters in the same way,
>> which is also what glibc's devstream does -- otherwise currently I
>> don't see what I'm typing on the console).
>>
>> Make sure to use the very latest glibc (Samuel has already pushed all
>> of my patches upstream!) + the BRK_START hack.
>>
>
>Thanks for the instructions. I was able to make it work and pushed my
>changes to Github.
>
>For people that might want to try out the new port using
>https://github.com/flavioc/cross-hurd,
>the following will download the packages and build a disk image with the
>ram disk:
>
>$ export CPU=x86_64
>$ bash download.sh && bash bootstrap.sh && bash compile.sh && bash
>create-initrd.sh
>
>Then, to run qemu:
>
>$ bash start-qemu-debug.sh
>
Thanks. I wonder how i can run create.sh in docker. I use debian in docker on fedora 38.
I think one blocker is to be able to use loopback devices inside the container
which is not supported unless the container is run with the SYS_ADMIN capability.
That's usually not recommended since it gives "root" access to the host. I think there
might be a way to build the ramdisk without using any of the loopback/mount
machinery (maybe with genext2fs?) but never tried to use that before.
>
>> Sergey
>>