Okay, so I can’t really go into too much of the big picture since this is from the day job, but I can certainly tear into gethostbyname_r() a bit.
For part of what we’re doing, we’re sending a RADIUS message using the freeradius project’s radius client library. So, nice and simple (after you’ve done some setup):
[cc escaped=”true” lang=”c”]result = rc_acct(rh, 0, send);[/cc]
Easy enough, right? So it fails. Specifically, it segfaults and since it’s in a multithreaded server, it’s a pain to track down. And I mean a pain. Hours of fun with DDD, gdb, nana and finally printf() lead to here:
[cc escaped=”true” lang=”c”]res = gethostbyname_r(hostname, &hostbuf, tmphostbuf, hostbuflen, &hp, &herr)[/cc]
Ah. gethostbyname_r(), the glibc2-reentrant thread-safe version of gethostbyname(). Except that it’s deprecated, and has the unique property of working differently on just about every machine out there.… Read the rest