Fixes https://github.com/coder/internal/issues/1035
Or, at least, closes a remaining race that seems pretty likely.
The tests in question write a file, close the file, then execute the file. Sometimes Linux errors saying "text file busy" which means the file is still open for writing.
What I think is going on is:
1. Test_sshConfigProxyCommandEscape goroutine opens the file and begins writing.
2. Some other, unrelated test execs a command, which causes a `fork()` syscall. The child process now has a copy of the file descriptor to our open file.
3. Test_sshConfigProxyCommandEscape goroutine executes the file and gets "text file busy".
4. The child process calls the `exec` syscall, which closes the file (due to `CLOEXEC` being set).
The race is very tight because 3 has to happen before 4 (and, 3 involves it's own fork/exec), but it's not impossible on a busy system.
c.f. #14233 which was an earlier attempt to fix this. It only prevented the subtests from running in parallel. When the subtests were all running in parallel, the flake was fairly likely because you've got all this fork() activity happening at the same time. But, since the main test was in parallel there is still a chance a totally different test is `fork`'ing at in inopportune time.
fixes#18199
Corrects handling of paths with spaces in the `Match !exec` clause we
use to determine whether Coder Connect is running. This is handled
differently than the ProxyCommand, so we have a different escape
routine, which also varies by OS.
On Windows, we resort to a pretty gnarly hack, but it does work and I
feel the only other option would be to reduce functionality such that we
could not detect the Coder Connect state.
* fix: Use smarter quoting for ProxyCommand in config-ssh
This change takes better into account how OpenSSH executes
`ProxyCommand`s and applies quoting accordingly.
This supercedes #3664, which was reverted.
Fixes#2853
* fix: Ensure `~/.ssh` directory exists
Spike Curtis