On Mon, May 02, 2022 at 05:43:21PM +0200, Lennart Poettering wrote: > On Mo, 02.05.22 17:30, Jason A. Donenfeld (Jason@xxxxxxxxx) wrote: > > > Just wanted to double check with you that this change wouldn't break how > > you're using it in systemd for /proc/sys/kernel/hostname: > > > > https://github.com/systemd/systemd/blob/39cd62c30c2e6bb5ec13ebc1ecf0d37ed015b1b8/src/journal/journald-server.c#L1832 > > https://github.com/systemd/systemd/blob/39cd62c30c2e6bb5ec13ebc1ecf0d37ed015b1b8/src/resolve/resolved-manager.c#L465 > > > > I couldn't find anybody else actually polling on it. Interestingly, it > > looks like sd_event_add_io uses epoll() inside, but you're not hitting > > the bug that Jann pointed out (because I suppose you're not poll()ing on > > an epoll fd). > > Well, if you made sure this still works, I am fine either way ;-) Actually... ugh. It doesn't work. systemd uses uname() to read the host name, and doesn't actually read() the file descriptor after receiving the poll event on it. So I guess I'll forget this, and maybe we'll have to live with sysctl's poll() being broken. :( Jason
