building a rootfs without a kernel #493
Comments
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Huh, it works here. (You shouldn't need BUILTIN=1, that tells the kernel build to statically link the initramfs into the image rather than loading an external cpio.gz, shouldn't apply if you're not saying LINUX=/somewhere .) The first error is indeed "busybox find -type f,l" not working, it doesn't know how to do fallbacks. Toybox added that in 2020 (commit 70a55cf). This is a build under Alpine? |
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I'm flying between cities today and unlikely to have a chance to set up an alpine VM, but I note that I recently added scripts/prereq/build.sh to create a minimal toybox capable of running the rest of the build. The initial commit was d1acc6e and I got it working on the mac (without homebrew) in commit 3bbc31c . I need to do a proper fix so this "just works" again on alpine, but in the meantime you might be able to use the mac instructions to work around it? |
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I don't remember why I added This is a build on Alpine, but I'm happy to make it not be! I'll swap it to Debian and/or try out your Also, definitely not urgent -- I hope your travels are safe! 🙇 |
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Just pre-running I think I will switch to a Debian-based builder image though, especially since even with that it gives me weird output from BusyBox and I don't really want to be chasing that all the time. 😄 Thanks so much for your help and for such a fun project. 👍 ( |
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Ahhh, I remember why I was using Alpine now -- because otherwise glibc gets grouchy about the static build and warns about functions like I guess I'll go back to installing GNU tools in Alpine for now so the builds stay safe from glibc-isms and avoid the issues with BusyBox. 👍 |
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I tried to set up an alpine test environment (my last one was a chroot years ago), but it doesn't seem like they ship a livecd? Or at least the "extended" x86-64 image on their "downloads" page isn't one. I downloaded their CD, kvm -m 2048 -cdrom blah.iso and got a login prompt instead of a desktop, the only account I could guess was "root", then I couldn't "git clone https://toybox" because it didn't have "git" installed. I googled and did an "apk add git" but it said it didn't know the package, "apk update" and "apk upgrade" didn't help... This is not really a livecd. |
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Used the setup program to install it to a virtual disk, booted that, logged in, installed git, logged in as the non-root user I'd created, cloned the repo, there was no make... and no sudo. And "apk add sudo" didn't work. Right... Ok, installed make, there was no gcc, installed that, and now it says ctype.h not found. I have to install an additional package to get standard posix headers supplied by musl, installing the compiler does not get me headers. This is not the friendliest distro I've encountered. Also, what's the difference between the "extended" image and the "minimal" image? Installed musl-dev. Installed bash. And now the build is complaining linux/rfkill.h isn't installed... |
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I set up a busybox airlock directory (mv busybox dir; cd dir; for i in $(./busybox --list); do ln -s busybox $i; done) and stuck it at the start of the $PATH, and commit 7c6aecd build mkroot CROSS=i686 with that. (No LINUX= so it didn't build a kernel.) Hopefully that means it works on alpine again. I replaced the -type x,y with ( -type x -o -type y ) because that's what busybox understands, and the airlock setup succeeding should handle the rest... |
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Oof, sorry you went through so much trouble on my behalf! Hopefully it felt productive for you? 🙈 If you need Alpine again (or want to set up some kind of CI / automated builds / testing) and are OK with a chroot, I'd suggest instead using the minirootfs tarballs from https://dl-cdn.alpinelinux.org/alpine/latest-stable/releases/x86_64/ (or the suitable alternatives from another directory if you're on a different architecture ❤️). 😄 I tested using https://github.com/landley/toybox/archive/aedbaa5c4d451859b0e8b470e9520f722915bda0.tar.gz in place of the release tarballs (aedbaa5 being current HEAD), got rid of GNU's Step 5/9 : RUN make root
---> Running in 15b164a9d71b
mkroot/mkroot.sh
...................
find: /usr/local/sbin: No such file or directory
Building for host
mkroot/mkroot.sh: line 157: toybox: command not found
mkroot/mkroot.sh: line 20: /dev/tty: No such device or address
=== toybox
cleaned
cc -o kconfig/conf kconfig/conf.c kconfig/zconf.tab.c -DKBUILD_NO_NLS=1 \
-DPROJECT_NAME=\"ToyBox\"
scripts/genconfig.sh
kconfig/conf -D /dev/fd/63 Config.in > /dev/null
scripts/make.sh
warning: using unfinished code from toys/pending
generated/{Config.in,newtoys.h,flags.h,tags.h,help.h}
Compile toybox
...............................................................................................................................................................................................................
scripts/install.sh --long --symlink --force
Compile instlist...
Install commands...
No $LINUX directory, kernel build skipped.
mkroot/mkroot.sh: line 20: /dev/tty: No such device or address
=== initramfs
find: unrecognized: -printf
cpio: unknown user/group +0:+0
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: find [-HL] [PATH]... [OPTIONS] [ACTIONS]
Search for files and perform actions on them.
First failed action stops processing of current file.
Defaults: PATH is current directory, action is '-print'
-L,-follow Follow symlinks
-H ...on command line only
-xdev Don't descend directories on other filesystems
-maxdepth N Descend at most N levels. -maxdepth 0 applies
actions to command line arguments only
-mindepth N Don't act on first N levels
-depth Act on directory *after* traversing it
Actions:
( ACTIONS ) Group actions for -o / -a
! ACT Invert ACT's success/failure
ACT1 [-a] ACT2 If ACT1 fails, stop, else do ACT2
ACT1 -o ACT2 If ACT1 succeeds, stop, else do ACT2
Note: -a has higher priority than -o
-name PATTERN Match file name (w/o directory name) to PATTERN
-iname PATTERN Case insensitive -name
-path PATTERN Match path to PATTERN
-ipath PATTERN Case insensitive -path
-regex PATTERN Match path to regex PATTERN
-type X File type is X (one of: f,d,l,b,c,s,p)
-executable File is executable
-perm MASK At least one mask bit (+MASK), all bits (-MASK),
or exactly MASK bits are set in file's mode
-mtime DAYS mtime is greater than (+N), less than (-N),
or exactly N days in the past
-atime DAYS atime +N/-N/N days in the past
-ctime DAYS ctime +N/-N/N days in the past
-mmin MINS mtime is greater than (+N), less than (-N),
or exactly N minutes in the past
-newer FILE mtime is more recent than FILE's
-inum N File has inode number N
-user NAME/ID File is owned by given user
-group NAME/ID File is owned by given group
-size N[bck] File size is N (c:bytes,k:kbytes,b:512 bytes(def.))
+/-N: file size is bigger/smaller than N
-links N Number of links is greater than (+N), less than (-N),
or exactly N
-empty Match empty file/directory
-prune If current file is directory, don't descend into it
If none of the following actions is specified, -print is assumed
-print Print file name
-print0 Print file name, NUL terminated
-exec CMD ARG ; Run CMD with all instances of {} replaced by
file name. Fails if CMD exits with nonzero
-exec CMD ARG + Run CMD with {} replaced by list of file names
-delete Delete current file/directory. Turns on -depth option
-quit Exit
Output is in /toybox/root/host
Removing intermediate container 15b164a9d71b(happy to share more details if you want them, or test more things, but this seems good 👍) Again, I really appreciate it, and enjoy playing with and using Toybox. 😁 |
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Ah, the downloadable chroot is probably what I used last time. I want it to work, you brought me an example of it not working, I'm gnawing at it. Huh, it looks like it's not installing the airlock (which is why attempting to set VERSION via toybox --version is not finding it). I wonder why? The /dev/tty thing is harmless (announce is trying to change your title bar), I suppose I could add a 2>/dev/null to suppress it, I've just never encountered it before... The busybox find -printf thing at the end is again, because busybox doesn't support an option both toybox and gnu do, and it didn't build the airlock for some reason. |
I've been using
make root BUILTIN=1to build just a rootfs (for use in containers, which I maintain builds of at https://hub.docker.com/r/tianon/toybox; easier to browse at https://oci.dag.dev/?repo=tianon/toybox). Because containers run directly on the host kernel, there's no need for this to contain a kernel (very similar to a chroot use case, really). 😄As of the new 0.8.11 that is no longer working, with cryptic
cpioerrors. I think the refactoring in 97b776b is what made that stop working, but I'm not 100% sure. 🤔Perhaps what I'm trying to do is actually an unsupported use case? I'm very open to suggestions here. 😄 🙇 ❤️
Output from the `Dockerfile` as-is (with the 0.8.11 bump):
The same, but this time with GNU `find` and `cpio` (via Alpine's `findutils` and `cpio` packages) instead of the BusyBox implementations Alpine gives us by default to resolve some of the errors seen in the above output (but still ultimately failing):
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