Avoids a race where the pipe could be inherited by another process
spawning at about the same time. If the other process didn't exit
quickly (e.g. if it was a custom script that did its own looping), it
would keep the write end of the pipe open, and so reading from the pipe
to try to get the command's output would block.
This bug manifested as some custom modules randomly not appearing in the
bar, requiring a reload to fix. The custom script had run and exited,
but the pipe had been inherited by another process, and the thread that
updated the module's output was blocked trying to read from it.
(Fixes #358.)
Subprocesses created for custom module scripts were previously left
running when the parent Waybar process exited. This patch sets the
parent-death signal of child processes (PR_SET_PDEATHSIG on Linux,
PROC_PDEATHSIG_CTL on FreeBSD) to SIGTERM.
Caveats:
* This uses Linux-specific or FreeBSD-specific calls. I don’t know if
this project targets other systems?
* There is a possibility that Waybar exits after calling `fork()`, but
before calling `prctl` to set the parent-death signal. In this case,
the child will not receive the SIGTERM signal and will continue to
run. I did not handle this case as I consider it quite unlikely, since
module scripts are usually launched only when Waybar starts. Please
let me know if you think it needs to be handled.
Testing:
* With `htop` open, run Waybar v0.9.5 with a custom module that has an
`exec` script. Terminate the Waybar process and notice that the
script’s subprocess stays alive and is now a child of the init
process.
* Run Waybar with this patch and follow the same steps as above. Notice
that this time the script’s subprocess terminates when the parent
exits.
When forkExec is called it begins to ignore all SIGCHLD signals for
the rest of the progam's execution so that they are automatically
reaped. However, this means that subsequent waitpid calls in the exec
function will always fail. So instead handle SIGCHLD by reaping any
processes created by forkExec and ignoring all others so that they can be
handled directly by the exec function.
In file included from ../src/modules/custom.cpp:1:
In file included from ../include/modules/custom.hpp:7:
../include/util/command.hpp:15:25: error: implicit instantiation of undefined template 'std::__1::array<char, 128>'
std::array<char, 128> buffer = {0};
^
../src/modules/pulseaudio.cpp:175:41: error: implicit instantiation of undefined template 'std::__1::array<std::__1::basic_string<char>, 9>'
static const std::array<std::string, 9> ports = {
^
/usr/include/c++/v1/__tuple:223:64: note: template is declared here
template <class _Tp, size_t _Size> struct _LIBCPP_TEMPLATE_VIS array;
^
In file included from ../src/factory.cpp:1:
In file included from ../include/factory.hpp:8:
../include/modules/sway/workspaces.hpp:39:8: error: no template named 'unordered_map' in namespace 'std'
std::unordered_map<std::string, Gtk::Button> buttons_;
~~~~~^
../src/factory.cpp:20:14: error: cannot initialize return object of type 'waybar::AModule *' with an rvalue of type 'waybar::modules::sway::Workspaces *'
return new waybar::modules::sway::Workspaces(id, bar_, config_[name]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This patch adds 3 new configuration options applicable for
subclasses of ALabel. The options can be used to execute
user defined code in response to the 3 mouse events:
* on-click: The left mouse button click
* on-scroll-up
* on-scroll-down
This patch also modifies the behaviour of the format-alt toggle
such that when the on-click event is configured, format-alt is
toggled on any mouse click other than left click. When on-click
is not defined, any mouse button would toggle format-alt.
Signed-off-by: Harish Krupo <harishkrupo@gmail.com>
