This ensures these functions are always called (even when a library
such as wlroots or libc perform the fork) and removes the need to
manually call them.
cmd_exec_process is used whenever sway is meant to execute a child
process on behalf of the user, and had a lot of complexity.
In order to avoid having to wait on the user's process, a double-fork
was used, which in turn required us to wait on the outer process. In
order to track the child PID for launcher purposes, a pipe was used to
transmit the PID back to sway.
This resulted in sway blocking for 5-6 ms per exec on my system, which
is quite significant. The error handling was also quite lacking - the
read loop did not handle errors at all for example.
Instead, teach sway to handle SIGCHLD and do away with the double-fork.
This in turn allows us to get rid of the pipe as we can record the
child's PID directly. This reduces the time we block to just 1.5 ms on
my system. We'd be able to get down to just 150 µs if we could use
posix_spawn(3), but posix_spawn(3) cannot reset NOFILE. clone(2) or
vfork(2) would be alternatives, but that presents portability issues.
This change is replicated for swaybar, swaybg and swaynag handling,
which had similar albeit less complicated implementations.
Wayland compositors handle many file descriptors: client
connections, DMA-BUFs, sync_files, wl_data_device pipes, and so
on. Bump the limit to the max.
Closes: https://github.com/swaywm/sway/issues/6285
set_cloexec is defined by both sway and wlroots (and who-knows-else),
so rename the sway one for supporting static linkage. We also remove
the duplicate version of this in client/.
Fixes: https://github.com/swaywm/sway/issues/4677
This commit mostly duplicates the wlr_log functions, although
with a sway_* prefix. (This is very similar to PR #2009.)
However, the logging function no longer needs to be replaceable,
so sway_log_init's second argument is used to set the exit
callback for sway_abort.
wlr_log_init is still invoked in sway/main.c
This commit makes it easier to remove the wlroots dependency for
the helper programs swaymsg, swaybg, swaybar, and swaynag.
- Some platforms don't expose kill() unless _POSIX_C_SOURCE is defined.
- fork(), execl(), and setsid() need unistd.h on some platforms.
Basically, this fixes some platform-specific build errors.
