The tty_ownership test was sometimes failing. In this test,
`fish_test_helper` creates a child and transfers the tty to it,
"abandoning" the tty. In some cases, the child was running before the
parent; the child claims the tty. When the parent tries to transfer it to
the child, it get SIGTTIN and stops. Fix this by ignoring SIGTTIN and
SIGTTOU.
This only affects macOS and BSDs.
It turns out there *is* an obviously portable way... except it's
not-so-obviously not portable after all.
POSIX specifies that sigqueue(2) can be used to validate pid and signo
separately, returning EINVAL in the specific case of an invalid or unsupported
signal number. This would be perfect... if only it were actually implemented.
When fish runs with job control enabled, it transfers ownership of the
tty to a child process, and then reclaims the tty after the process
exits. If job control is disabled then fish does not transfer or reclaim
the tty.
It may happen that the child process creates a pgroup and then transfers
the tty to it. In that case fish will not attempt to reclaim the tty, as
fish did not transfer it. Then when fish reads from stdin it will
receive SIGTTIN instead of data.
Fix this by unconditionally claiming the tty in readline().
Fixes#9181
When fish starts, it notices which pgroup owns the tty, and then it
restores that pgroup's tty ownership when it exits. However if fish does
not own the tty, then (on Mac at least) the tcsetpgrp call triggers a
SIGSTOP and fish will hang while trying to exit.
The first change is to ignore SIGTTOU instead of defaulting it. This
prevents the hang; however it risks re-introducing #7060.
The second change somewhat mitigates the risk of the first: only do the
restore if the initial pgroup is different than fish's pgroup. This
prevents some useless calls which might potentially steal the tty from
another process (e.g. in #7060).
And again clang-format does something I don't like:
- if (found != end && std::strncmp(found->name, name, len) == 0 && found->name[len] == 0) return found;
+ if (found != end && std::strncmp(found->name, name, len) == 0 && found->name[len] == 0)
+ return found;
I *know* this is a bit of a long line. I would still quite like having
no brace-less multi-line if *ever*. Either put the body on the same
line, or add braces.
Blergh
warn_unused_result is the persistent one that won't go away with a
simple `(void)write(...)` and needs to be assigned to a variable (that
must then also be declared unused or else you'll get a warning about
_that_).
Prior to this fix, when key binding is a script command (i.e. not a
readline command), fish would run that key binding using fish's shell
tty modes. Switch to using the external tty modes. This re-fixes
issue #2214.
This changes how fish attempts to protect itself from calling tcsetpgrp() too
aggressively. Recall that tcsetpgrp() will "force" itself, if SIGTTOU is
ignored (which it is in fish when job control is enabled).
Prior to this fix, we avoided SIGTTINs by only transferring the tty ownership
if fish was already the owner. This dated from a time before we had really
nailed down how pgroups should be assigned. Now we more deliberately assign a
job's pgroup so we don't need this conservative check.
However we still need logic to avoid transferring the tty if fish is not the
owner. The bad case is when job control is enabled while fish is running in the
background - here fish would transfer the tty and "steal" from the foreground
process.
So retain the checks of the current tty owner but migrate them to the point of
calling tcsetpgrp() itself.
This just produced a spurious "Unknown signal" error on NetBSD and OpenBSD, and
the number picked was arbitrary. So let's just use the maximum that
appears to work everywhere.
(I will hate this if I test it elsewhere and need to reduce it to 62)
(This is a squashed commit, I did indeed hate it when I moved from
NetBSD to OpenBSD)
Otherwise it would print "Unknown Signal" on Linux. I didn't see an
obvious way to check signal validity, plus it hardly matters.
Also mimic the output from BSD strsignal on Linux.
I kinda hate how fussy clang-format is. It reflows text
constantly (line limit), forces things onto one line *except* when
they're too long, and wants to turn this:
```c++
return true;;
```
into this:
```c++
return true;
;
```
instead of, you know, eliminating the second semicolon?
Anyway, it is what it is and we use it, I'll just look into getting some
more slack.
'fish_test_helper print_pid_then_sleep' tried to sleep for .5 seconds,
but instead it divided by .5 so it actually slept for 2 seconds.
This exceeds the maximum value on NetBSD so it wasn't sleeping at all
there.
Fixes#6476
The IO cleanup left file redirections open in the child. For example,
/bin/cmd < file.txt would redirect stdin but also leave the file open.
Ensure these get closed properly.
In tests we would like to arrange for an executable to invoke certain
system calls, e.g. to claim or relinquish control of the terminal. This is
annoying to do portably via e.g. perl. fish_test_helper is a little
program where we can add custom commands to make it act in certain ways.
