These changes should fix the signal "problems" in ppp.
The signal changes should really be put into 2.2 too !
The following patches should do it. There were some other
changes made by Andrey recently that havn't been brought
into 2.2, it may be worth doing them now.
dangerous! Signal handlers themself must be fixed to not call malloc,
but no pended handlers, it will be correct fix. In finite case each signal
handler can set some variable which will be analized later, but calling
handler functions manually is too dangerous (f.e. signals not blocked while
the handler or handlers switch executed in this case). Of course this
code can be fixed instead of removing, but it not worth fixing in any case.
Should go into 2.2
In addition sig.c code shows following dangerous fragments (there can be more,
but I stop after two):
This fragment
if (fn == SIG_DFL || fn == SIG_IGN) {
handler[sig-1] = (sig_type)0;
<------------- here
signal(sig,fn);
} else {
cause NULL pointer reference when signal comes
"here", but more worse fragment is below:
void handle_signals() {
int sig;
if (caused)
for (sig=0; sig<__MAXSIG; sig++, caused>>=1)
if (caused&1)
(*handler[sig])(sig+1);
}
caused is bitmask which set corresponding bit on each signal coming.
And now imagine, what happens when some signal comes (bit sets) while loop
is executed (see caused>>=1 !!!)
In this light carrier drop situation was (as gdb shows)
1. SIGSEGV in handle_signals because some junk called as *handler reference.
2. Since SIGSEGV was pended too (== never happens),
it can cause various range of disasters.
Remove #include's from sig.h and get dependant modules to include them
themselves. Make inclusion of if_var.h depend on __FreeBSD_version so
that the -current version of ppp can be used with 2.1.*
2.2 Candidate ?
All signal() calls have been changed to pending_signal() calls.
pending_signal() is defined in the new sig.c file. It remembers
the handler and traps the signal with a function that will remember
the signal.
main.c now calls handle_signals() to actually call the required
handlers (if the above handler was called).
If this doesn't close PR2662 (was PR2347), I'll cry.
Joerg, I think this should go into 2.2, but I havn't done anything
about it because I'm bound to botch it with the new sig.[ch] files.
I've just "cvs add"'d sig.[ch] so far.... can you update to 2.2 and
tell me what you did ? Thanks.
