I tried to understand why two dbus processes are started.
First, I replaced /usr/lib/cups/notifier/dbus with this program:
#include <unistd.h>
int main(void)
{
char buf[8192];
while (read(STDIN_FILENO, buf, sizeof buf) > 0) ;
return 0;
}
Then I printed a file, after which two dbus processes appeared in
"systemctl status cups". Then I did "strace" on both these processes
and printed another job. The output of strace showed what data is
received by these dbus processes. It is in attachment.
Note, that data is almost identical - do "diff cups1 cups2" to see the
differences.
So, the question is - why two dbus processes are started instead of one?
Attachment:
cups1
Description: Binary data
Attachment:
cups2
Description: Binary data