[Xymon] xymonnet - fatal signal caught

[Mark Felder]

I am now hitting this upon the upgrade to 4.3.18. I've tried building
against the supplied c-ares instead of the system c-ares (1.10.0 on
FreeBSD) to no effect.

vm# gdb ../bin/xymonnet xymonnet.core
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This GDB was configured as "amd64-marcel-freebsd"...
Core was generated by `xymonnet'.
Program terminated with signal 6, Aborted.
Reading symbols from /usr/lib/libssl.so.7...done.
Loaded symbols for /usr/lib/libssl.so.7
Reading symbols from /lib/libcrypto.so.7...done.
Loaded symbols for /lib/libcrypto.so.7
Reading symbols from /usr/local/lib/libpcre.so.1...done.
Loaded symbols for /usr/local/lib/libpcre.so.1
Reading symbols from /lib/libc.so.7...done.
Loaded symbols for /lib/libc.so.7
Reading symbols from /lib/libthr.so.3...done.
Loaded symbols for /lib/libthr.so.3
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x0000000801266a1a in kill () from /lib/libc.so.7
[New Thread 801c06400 (LWP 100117/xymonnet)]
(gdb) bt
#0  0x0000000801266a1a in kill () from /lib/libc.so.7
#1  0x0000000801265149 in abort () from /lib/libc.so.7
#2  0x0000000000423f01 in sigsegv_handler (signum=<value optimized out>)
at sig.c:57
#3  <signal handler called>
#4  0x0000000801262f8b in strlen () from /lib/libc.so.7
#5  0x0000000000425218 in addtobuffer_many (buf=0x801c19830) at
strfunc.c:140
#6  0x000000000041199c in display_rr (aptr=<value optimized out>,
abuf=<value optimized out>, alen=<value optimized out>,
response=0x801cd9100) at dns2.c:475
#7  0x00000000004111f3 in dns_detail_callback (arg=0x801cd9100,
status=<value optimized out>, timeouts=<value optimized out>,
abuf=0x7fffffffb2f0 "▒▒\205", alen=130) at dns2.c:268
#8  0x000000000041814d in search_callback ()
#9  0x0000000000417b7e in qcallback ()
#10 0x0000000000417113 in end_query ()
#11 0x000000000041788e in process_answer ()
#12 0x00000000004168c7 in processfds ()
#13 0x000000000041067b in dns_ares_queue_run (channel=0x801d07000) at
dns.c:172
#14 0x0000000000410b23 in dns_test_server (serverip=<value optimized
out>, hostname=0x801c19744 "feld.me", banner=0x801c19750) at dns.c:341
#15 0x000000000040a694 in main (argc=4, argv=0x7fffffffc990) at
xymonnet.c:1049



Even with xymonnet --no-ares it will crash. It seems that does not turn
off the c-ares codepath entirely as c-ares is still mentioned in the
backtrace.

Does anyone have any clue what is causing this? I see in the backtrace
at #7 that may very well be some unicode character it is choking on, but
I don't have any unicode characters in DNS... If this is really an
intermittent problem with c-ares it would be wise to consider an
alternative that is under heavy development like libasr:
https://www.opensmtpd.org/announces/libasr-1.0.0.txt