Re: [PATCH glibc] Stop checking if MiG supports retcode.

[Guy-Fleury Iteriteka]

On May 27, 2023 8:42:27 AM GMT+02:00, "Flávio Cruz" <flaviocruz@gmail.com> 
wrote:
>On Fri, May 26, 2023 at 9:42 AM Guy-Fleury Iteriteka <gfleury@disroot.org>
>wrote:
>
>> 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.
>
>
Thanks i was able to make it work. I will install qemu and play with it
>
>> >
>> >> Sergey
>> >>
>>
>>