Hi, Quoting Francesco Poli (2024-01-29 00:07:08) > What's *your* umask? Is it Debian default (022), by chance?
yes. > This seems to work with Debian default umask (022): > > $ printf '%o\n' "$(( 0666 - 00022 ))" > 644 > > but fails whenever a umask includes an octal digit equal to 7, due to > the carryover: > > $ printf '%o\n' "$(( 0666 - 00007 ))" > 657 > > Shouldn't this use the bitwise AND combined with the bitwise NOT? > > $ umask > 0007 > $ printf '%o\n' "$(( 0666 & ~0$(umask) ))" > 660 > $ umask 022 > $ umask > 0022 > $ printf '%o\n' "$(( 0666 & ~0$(umask) ))" > 644 > > I would think that mmdebstrap-autopkgtest-build-qemu should run: > > chmod "$(printf %o "$(( 0666 & ~0$(umask) ))")" "$IMAGE" > > Does it make sense to you? I now have this locally. Is this attribution (name/email) correct? >From 8410dc6636817c4e02cf9eba090a70051c494c48 Mon Sep 17 00:00:00 2001 From: Francesco Poli <[email protected]> Date: Mon, 29 Jan 2024 08:28:53 +0100 Subject: [PATCH] mmdebstrap-autopkgtest-build-qemu: fix octal mode computation --- mmdebstrap-autopkgtest-build-qemu | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mmdebstrap-autopkgtest-build-qemu b/mmdebstrap-autopkgtest-build-qemu index 5684cbe..1ed14db 100755 --- a/mmdebstrap-autopkgtest-build-qemu +++ b/mmdebstrap-autopkgtest-build-qemu @@ -357,7 +357,7 @@ echo "mmdebstrap $*" mmdebstrap "$@" || die "mmdebstrap failed" unshare -U -r --map-groups=auto chown 0:0 "$IMAGE" -chmod "$(printf %o "$(( 0666 - 0$(umask) ))")" "$IMAGE" +chmod "$(printf %o "$(( 0666 & ~0$(umask) ))")" "$IMAGE" echo "root=LABEL=autopkgtestvm rw console=ttyS0" > "$WORKDIR/cmdline" -- 2.39.2 > > Can you list some reasons why qcow2 should be preferred over > > raw images? > > I was under the impression that the qcow2 format was the recommended > one for QEMU/KVM virtual machine images. At least, qemu-img(1) > describes it as "the most versatile format"... > > Anyway, if you think that the raw format is a better choice for > autopkgtest and sbuild VM images, I take your word for it. I'm asking because I'm not the expert. :) I asked in #debian-devel and f_g (Fabian Grünbichler) commented that the main reasoning for choosing qcow over raw images is snapshot, link clone and backing image support. I don't think these features are useful for users of autopkgtest or sbuild with these images. Or do you see a use for them in this area? Thanks! cheers, josch
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