~\/.irssi<\/code>.<\/p>\nThen I wrote a wrapper script to do the runtime setup for starting irssi, as follows:<\/p>\n
#!\/bin\/sh\r\nset -e\r\nTMPDIR=`mktemp -d \/tmp\/stump_irc_XXXXXX`\r\ntrap 'rm -rf \"$TMPDIR\"' 0 1 2 15\r\ncp -a ~\/irc.keytab \"$TMPDIR\"\/keytab\r\nk5start -U -f \"$TMPDIR\"\/keytab -k \"$TMPDIR\"\/krb5cc -t -- irssi \"$@\"<\/pre>\n(The reason for copying the keytab into the temp dir is that k5start<\/code> sets up a PAG, and thereby loses access to the AFS tokens it was started with, before it reads the keytab. And if, like me, you’re in the [very good!] habit of exec<\/code>-ing the real program when you write a wrapper script, note that you can’t do this here due to the trap<\/code>.)<\/p>\nNow I can just run that script in a screen and get an irssi that will continue working indefinitely.<\/p>\n
<\/p>\n
…or it would, but because AFS only writes back file contents on close<\/code> or fsync<\/code>, each channel’s archive since the last time it was (re-)joined cannot be viewed from other systems. And worse, if the machine loses power or otherwise shuts down ungracefully (which semi-regularly happens, due to the state of constant flux the ACM systems are in, though things are much better now than they were when I first set this up), those spans of archives fall on the floor, which is very sad.<\/p>\nSo I wrote a quick script to call fsync<\/code> on every file descriptor irssi has open (because there was no obvious way to figure out which ones were the logfiles, I just took the brute force approach) every so often. Here it is:<\/p>\nuse strict;\r\nuse warnings;\r\n\r\nuse Irssi;\r\nuse IO::Handle;\r\nuse POSIX;\r\n\r\nmy $VERSION = '0.1';\r\nmy %IRSSI = (\r\n 'authors' => 'John Stumpo',\r\n 'name' => 'fsync.pl',\r\n 'description' => 'Periodically fsync()s all file descriptors irssi has open',\r\n 'license' => 'Public domain (CC0)',\r\n);\r\n\r\nour $FSYNC_MSECS = 300000; # every 5 minutes\r\n\r\nsub fsync_everything {\r\n my $io = IO::Handle->new();\r\n for (my $fd = 0; $fd < 1024; $fd++) {\r\n # Sadly, modern Perls don't let you just call POSIX::fsync on an int,\r\n # insisting that you do it through an IO::Handle, which has the highly\r\n # undesirable (for us) behavior of closing the file descriptor when the\r\n # object goes away without any documented-reliable way to override this.\r\n # Therefore, dup the fd first, and fsync and close the duplicate. The dup\r\n # also serves as a check that $fd is actually an open file descriptor.\r\n my $duped_fd = POSIX::dup($fd);\r\n next unless defined($duped_fd);\r\n $io->fdopen($duped_fd, 'r');\r\n $io->sync();\r\n $io->close();\r\n }\r\n}\r\n\r\nIrssi::timeout_add($FSYNC_MSECS, \\&fsync_everything, undef);<\/pre>\nAs the comment says, it would have been nice to just call POSIX::fsync<\/code> on each int from 0 to some reasonable value and ignore errors (as I could by using fsync<\/code> from C or os.fsync<\/code>\u00a0from Python), but Perl doesn’t let you do that anymore without going through a handle object that closes the file descriptor when it goes away and doesn’t give you a choice about that, hence the dance with POSIX::dup<\/code>. (And closing a dup<\/code>‘d file descriptor that goes into AFS doesn’t flush cached writes\u00a0– only when the last file descriptor closes does that happen, aside from fsync<\/code> being\u00a0called.)<\/p>\nHappy IRCing on AFS!<\/p>\n","protected":false},"excerpt":{"rendered":"
For the vast majority of my IRC needs, I used to use a Quassel core. But for a couple of more lighthearted channels I hang out in, I instead started using (and have since folded the rest of my IRC setup into) what on its face appears to be a traditional irssi-in-screen setup on a […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[],"_links":{"self":[{"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/posts\/181"}],"collection":[{"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/comments?post=181"}],"version-history":[{"count":10,"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/posts\/181\/revisions"}],"predecessor-version":[{"id":233,"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/posts\/181\/revisions\/233"}],"wp:attachment":[{"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/media?parent=181"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/categories?post=181"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stump.io\/blog\/wp-json\/wp\/v2\/tags?post=181"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}