/usr/bin/toolbox linked against glibc-2.32 doesn't run on older glibc #529
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This looks like the container failed to start. Once you have attempted to |
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I did and this is the error message: Here is with the |
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Yep, this is not good. Basically some library pulled in by the Toolbox code uses C code requiring the use of cgo. When |
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Yes, as @HarryMichal mentioned, this is the problematic part: It means that a We end up in this situation because we bind mount |
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I grabbed the Fedora 33 binary, unpacked it and poked at it a bit. Looks like there's a new implementation of |
debarshiray
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debarshiray
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Aug 21, 2020
The /usr/bin/toolbox binary is not only used to interact with toolbox
containers and images from the host. It's also used as the entry point
of the containers by bind mounting the binary from the host into the
container. This means that the /usr/bin/toolbox binary on the host must
also work inside the container, even if they have different operating
systems.
In the past, this worked perfectly well with the POSIX shell
implementation because it got intepreted by whichever /bin/sh was
available.
The Go implementation also mostly worked so far because it's largely
statically linked, with the notable exception of the standard C
library. However, recently glibc-2.32, which is used by Fedora 33
onwards, added a new version of the pthread_sigmask symbol [1] as part
of the libpthread removal project.
This means that /usr/bin/toolbox binaries built against glibc-2.32 on
newer Fedoras pick up the latest version of the symbol and fail to run
against older glibcs in older Fedoras.
One way to fix this is to disable the use of any C code from Go by
using the CGO_ENABLED environment variable [2]. However, this can
negatively impact packages like "os/user" [3] and "net" [4], where the
more featureful glibc APIs will be replaced by more limited
equivalents written only in Go.
Instead, since glibc uses symbol versioning, it's better to tell the
Go toolchain to avoid linking against any symbols from glibc-2.32.
This was accomplished by a few linker tricks:
* The GNU ld linker's --wrap flag was used when building the Go code
to divert pthread_sigmask invocations from Go to another function
called __wrap_pthread_sigmask.
* A static library was added to provide this __wrap_pthread_sigmask
function, which forwards calls to the actual pthread_sigmask API in
glibc. This library itself was not linked with --wrap, and
specifies the latest permissible version of the pthread_sigmask
symbol from glibc for each architecture. Currently, the list of
architectures covers the ones that Fedora builds for.
* The Go cmd/link linker was switched to external mode [5]. This
ensures that the final object file containing all the Go code gets
linked to the standard C library and the wrapper static library by
the GNU ld linker for the --wrap flag to kick in.
Based on ideas from Ondřej Míchal.
[1] glibc commit c6663fee4340291c
https://sourceware.org/git/?p=glibc.git;a=commit;h=c6663fee4340291c
[2] https://golang.org/cmd/cgo/
[3] https://golang.org/pkg/os/user/
[4] https://golang.org/pkg/net/
[5] https://golang.org/src/cmd/cgo/doc.go
containers#529
debarshiray
added a commit
to debarshiray/toolbox
that referenced
this issue
Aug 21, 2020
The /usr/bin/toolbox binary is not only used to interact with toolbox
containers and images from the host. It's also used as the entry point
of the containers by bind mounting the binary from the host into the
container. This means that the /usr/bin/toolbox binary on the host must
also work inside the container, even if they have different operating
systems.
In the past, this worked perfectly well with the POSIX shell
implementation because it got intepreted by whichever /bin/sh was
available.
The Go implementation also mostly worked so far because it's largely
statically linked, with the notable exception of the standard C
library. However, recently glibc-2.32, which is used by Fedora 33
onwards, added a new version of the pthread_sigmask symbol [1] as part
of the libpthread removal project:
$ objdump -T ./usr/bin/toolbox | grep GLIBC_2.32
0000000000000000 DO *UND* 0000000000000000 GLIBC_2.32
pthread_sigmask
This means that /usr/bin/toolbox binaries built against glibc-2.32 on
newer Fedoras pick up the latest version of the symbol and fail to run
against older glibcs in older Fedoras.
One way to fix this is to disable the use of any C code from Go by
using the CGO_ENABLED environment variable [2]. However, this can
negatively impact packages like "os/user" [3] and "net" [4], where the
more featureful glibc APIs will be replaced by more limited
equivalents written only in Go.
Instead, since glibc uses symbol versioning, it's better to tell the
Go toolchain to avoid linking against any symbols from glibc-2.32.
This was accomplished by a few linker tricks:
* The GNU ld linker's --wrap flag was used when building the Go code
to divert pthread_sigmask invocations from Go to another function
called __wrap_pthread_sigmask.
* A static library was added to provide this __wrap_pthread_sigmask
function, which forwards calls to the actual pthread_sigmask API in
glibc. This library itself was not linked with --wrap, and
specifies the latest permissible version of the pthread_sigmask
symbol from glibc for each architecture. Currently, the list of
architectures covers the ones that Fedora builds for.
* The Go cmd/link linker was switched to external mode [5]. This
ensures that the final object file containing all the Go code gets
linked to the standard C library and the wrapper static library by
the GNU ld linker for the --wrap flag to kick in.
Based on ideas from Ondřej Míchal.
[1] glibc commit c6663fee4340291c
https://sourceware.org/git/?p=glibc.git;a=commit;h=c6663fee4340291c
[2] https://golang.org/cmd/cgo/
[3] https://golang.org/pkg/os/user/
[4] https://golang.org/pkg/net/
[5] https://golang.org/src/cmd/cgo/doc.go
containers#529
debarshiray
added a commit
to debarshiray/toolbox
that referenced
this issue
Aug 21, 2020
The /usr/bin/toolbox binary is not only used to interact with toolbox
containers and images from the host. It's also used as the entry point
of the containers by bind mounting the binary from the host into the
container. This means that the /usr/bin/toolbox binary on the host must
also work inside the container, even if they have different operating
systems.
In the past, this worked perfectly well with the POSIX shell
implementation because it got intepreted by whichever /bin/sh was
available.
The Go implementation also mostly worked so far because it's largely
statically linked, with the notable exception of the standard C
library. However, recently glibc-2.32, which is used by Fedora 33
onwards, added a new version of the pthread_sigmask symbol [1] as part
of the libpthread removal project:
$ objdump -T /usr/bin/toolbox | grep GLIBC_2.32
0000000000000000 DO *UND* 0000000000000000 GLIBC_2.32
pthread_sigmask
This means that /usr/bin/toolbox binaries built against glibc-2.32 on
newer Fedoras pick up the latest version of the symbol and fail to run
against older glibcs in older Fedoras.
One way to fix this is to disable the use of any C code from Go by
using the CGO_ENABLED environment variable [2]. However, this can
negatively impact packages like "os/user" [3] and "net" [4], where the
more featureful glibc APIs will be replaced by more limited
equivalents written only in Go.
Instead, since glibc uses symbol versioning, it's better to tell the
Go toolchain to avoid linking against any symbols from glibc-2.32.
This was accomplished by a few linker tricks:
* The GNU ld linker's --wrap flag was used when building the Go code
to divert pthread_sigmask invocations from Go to another function
called __wrap_pthread_sigmask.
* A static library was added to provide this __wrap_pthread_sigmask
function, which forwards calls to the actual pthread_sigmask API in
glibc. This library itself was not linked with --wrap, and
specifies the latest permissible version of the pthread_sigmask
symbol from glibc for each architecture. Currently, the list of
architectures covers the ones that Fedora builds for.
* The Go cmd/link linker was switched to external mode [5]. This
ensures that the final object file containing all the Go code gets
linked to the standard C library and the wrapper static library by
the GNU ld linker for the --wrap flag to kick in.
Based on ideas from Ondřej Míchal.
[1] glibc commit c6663fee4340291c
https://sourceware.org/git/?p=glibc.git;a=commit;h=c6663fee4340291c
[2] https://golang.org/cmd/cgo/
[3] https://golang.org/pkg/os/user/
[4] https://golang.org/pkg/net/
[5] https://golang.org/src/cmd/cgo/doc.go
containers#529
|
I found a way to tell the Go toolchain to avoid the new version of the Testing welcome. |
debarshiray
added a commit
to debarshiray/toolbox
that referenced
this issue
Aug 21, 2020
The /usr/bin/toolbox binary is not only used to interact with toolbox
containers and images from the host. It's also used as the entry point
of the containers by bind mounting the binary from the host into the
container. This means that the /usr/bin/toolbox binary on the host must
also work inside the container, even if they have different operating
systems.
In the past, this worked perfectly well with the POSIX shell
implementation because it got intepreted by whichever /bin/sh was
available.
The Go implementation also mostly worked so far because it's largely
statically linked, with the notable exception of the standard C
library. However, recently glibc-2.32, which is used by Fedora 33
onwards, added a new version of the pthread_sigmask symbol [1] as part
of the libpthread removal project:
$ objdump -T /usr/bin/toolbox | grep GLIBC_2.32
0000000000000000 DO *UND* 0000000000000000 GLIBC_2.32
pthread_sigmask
This means that /usr/bin/toolbox binaries built against glibc-2.32 on
newer Fedoras pick up the latest version of the symbol and fail to run
against older glibcs in older Fedoras.
One way to fix this is to disable the use of any C code from Go by
using the CGO_ENABLED environment variable [2]. However, this can
negatively impact packages like "os/user" [3] and "net" [4], where the
more featureful glibc APIs will be replaced by more limited
equivalents written only in Go.
Instead, since glibc uses symbol versioning, it's better to tell the
Go toolchain to avoid linking against any symbols from glibc-2.32.
This was accomplished by a few linker tricks:
* The GNU ld linker's --wrap flag was used when building the Go code
to divert pthread_sigmask invocations from Go to another function
called __wrap_pthread_sigmask.
* A static library was added to provide this __wrap_pthread_sigmask
function, which forwards calls to the actual pthread_sigmask API in
glibc. This library itself was not linked with --wrap, and
specifies the latest permissible version of the pthread_sigmask
symbol from glibc for each architecture. Currently, the list of
architectures covers the ones that Fedora builds for.
* The Go cmd/link linker was switched to external mode [5]. This
ensures that the final object file containing all the Go code gets
linked to the standard C library and the wrapper static library by
the GNU ld linker for the --wrap flag to kick in.
Based on ideas from Ondřej Míchal.
[1] glibc commit c6663fee4340291c
https://sourceware.org/git/?p=glibc.git;a=commit;h=c6663fee4340291c
[2] https://golang.org/cmd/cgo/
[3] https://golang.org/pkg/os/user/
[4] https://golang.org/pkg/net/
[5] https://golang.org/src/cmd/cgo/doc.go
containers#529
|
Closing. Please feel free to leave a comment on the PRs or here if you think that it's still broken. Thanks for the testing, by the way. Much appreciated! |
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Describe the bug
Usually, you can run another Fedora release with toolbox by doing:
But at Fedora Rawhide you get the following error:
The full debug output:
Steps how to reproduce the behaviour
Expected behaviour
That toolbox would enter the container normally.
Actual behaviour
It fails to perform
enteron the container.Output of
toolbox --version(v0.0.90+)toolbox version 0.0.93Toolbox package info (
rpm -q toolbox)It was installed from the sources, no toolbox package installed.
Output of
podman versionPodman package info (
rpm -q podman)podman-2.1.0-0.169.dev.git162625f.fc33.x86_64`
Info about your OS
I tested in a virtual machine with Vagrant. The OS is Fedora 33.
It was a fresh installation from today (August 14th) and with all the packages updated.
Additional context
I tried with the releases 31 and 32. The release 33 (the same that the host) was working fine. Well, apart for the bug: #523
Also, I tied the same at another VM with Fedora 32 and it worked fine. I tried at that F32 VM with the releases 29, 31, 32 and 33, with no problems.
I notice though, that the entry point PID, the one from the error, was different. At the Rawhide system the PID was always
0, but at my system (Silverblue 32) and the VM (Fedora 32) were always a non-zero value. Something likePID=32612and such.For example (inside Fedora 32 VM):
The text was updated successfully, but these errors were encountered: