In the SSH code, the logger was conditionally paused, but unconditionally
resumed. This was fine as long as resuming the logger was idempotent. Starting
with 0dd1d8ca1c, it isn't any more, and the
behaviour of the code in question was missed. Consequently, an assertion
failure is triggered for example when performing builds against an "SSH" store
on localhost. Fix the issue by only resuming the logger when it has actually
been paused.
Fixes: lix-project/lix#458
Change-Id: Ib1e4d047744a129f15730b7216f9c9368c2f4211
copy-constructing or assigning from pid_t can easily lead to duplicate
Pid instances for the same process if a pid_t was used carelessly, and
Pid itself was copy-constructible. both could cause surprising results
such as killing processes twice (which could become very problemantic,
but luckily modern systems don't reuse PIDs all that quickly), or more
than one piece of the code believing it owns a process when neither do
Change-Id: Ifea7445f84200b34c1a1d0acc2cdffe0f01e20c6
add a reset() method to close the wrapped fd instead of assigning magic
constants. also make the from-fd constructor explicit so you can't
accidentally assign the *wrong* magic constant, or even an unrelated
integer that also just happens to be an fd by pure chance.
Change-Id: I51311b0f6e040240886b5103d39d1794a6acc325
These now have equivalents in the standard lib in C++20. This change was
performed with a custom clang-tidy check which I will submit later.
Executed like so:
ninja -C build && run-clang-tidy -checks='-*,nix-*' -load=build/libnix-clang-tidy.so -p .. -fix ../tests | tee -a clang-tidy-result
Change-Id: I62679e315ff9e7ce72a40b91b79c3e9fc01b27e9
Pause logger before starting SSH connections, and resume it after the
connection is established, so that SSH password prompts are not erased
by the logger's updates.
Currently, Nix passes `-a` when it runs commands on a remote machine via
SSH, which disables agent forwarding. This causes issues when the
`ForwardAgent` option is set in SSH config files, as the command line
operation always overrides those.
In particular, this causes issues if the command being run is `sudo`
and the remote machine is configured with the equivalent of NixOS's
`security.pam.enableSSHAgentAuth` option. Not allowing SSH agent
forwarding can cause authentication to fail unexpectedly.
This can currently be worked around by setting `NIX_SSHOPTS="-A"`, but
we should defer to the options in the SSH config files to be least
surprising for users.
This is already used by Hydra, and is very useful when materializing
a remote builder list from service discovery. This allows the service
discovery tool to only sync one file instead of two.
The ssh client is lazily started by the first worker thread, that
requires a ssh connection. To avoid the ssh client to be killed, when
the worker process is stopped, do not set PR_SET_PDEATHSIG.
If the `throw` is reached, this means that execvp into `ssh` wasn’t
successful. We can hint at a usual problem, which is a missing `ssh`
executable.
Test with:
```
env PATH= ./result/bin/nix-copy-closure --builders '' unusedhost
```
and the bash version with
```
env PATH= ./result/bin/nix-copy-closure --builders '' localhost
```
This reverts commit a0ef21262f. This
doesn't work in 'nix run' and nix-shell because setns() fails in
multithreaded programs, and Boehm GC mark threads are uncancellable.
Fixes#2646.
* Unify SSH code in SSHStore and LegacySSHStore.
* Fix a race starting the SSH master. We now wait synchronously for
the SSH master to finish starting. This prevents the SSH clients
from starting their own connections.
* Don't use a master if max-connections == 1.
* Add a "max-connections" store parameter.
* Add a "compress" store parameter.
