[Swan] SIGINT and xauth.c

D. Hugh Redelmeier hugh at mimosa.com
Mon Oct 7 06:27:27 EEST 2013


xauth.c has intricate sigal handling code.  I would like to understand its 
intent.

Where do these SIGINTs come from?  Do they all originate from the user 
typing the interrupt key while PAM(?) is asking for passwords?  Does it 
originate from PAM (I assume Pluto does not have a controling terminal so 
that it won't get SIGINT directly from the TTY driver).

There can be multiple threads outstanding, all using PAM.  How do we know 
that the SIGINT is routed to the thread correct thread?

In xauth.c, the signal handling code seems to be written as if the signal 
handler setting is global to all threads but that the actual signal is 
routed to the correct thread.  That surprises me.


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