Fix bug in sd-bus polling #282
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cillian64
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As I said in #281, this PR completely solves the random startup delay for me. I hope it will be merged in the near future |
emersion
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Nov 17, 2023
src/core/main.c
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| // sd-bus requires that we update FD/events/timeout every time we poll | ||
| pollfds[EVENT_LOOP_DBUS].fd = sd_bus_get_fd(state.bus); | ||
| if (pollfds[EVENT_LOOP_DBUS].fd < 0) { | ||
| logprint(ERROR, "sd_bus_get_fd failed: %s", strerror(errno)); |
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Nit: it doesn't seem like sd-bus populates errno. It seems like the error number is returned instead.
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LGTM apart from this nit. |
sd-bus requires that `sd_bus_get_fd`, `sd_bus_get_events`, and `sd_bus_get_timeout` are called for every invocation of `poll`, and the returned FD, events, and timeout used. In particular, sd-bus may return `events=0` and `timeout=0` if it already has dbus messages to process in its receive queue. xdpw currently doesn't call `sd_bus_get_events` or `sd_bus_get_timeout` at all. This can result in the situation where xdpw goes into a `poll` with no timeout and a message in sd-bus' receive queue is never handled until another dbus message arrives. I have a case where this ignored messages causes xdg-desktop-portal to hang. This commit changes the polling code to match sd-bus' requirements. Fixes emersion#281
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Thanks for the review! |
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sd-bus requires that
sd_bus_get_fd,sd_bus_get_events, andsd_bus_get_timeoutare called for every invocation ofpoll, and the returned FD, events, and timeout used. In particular, sd-bus may returnevents=0andtimeout=0if it already has dbus messages to process in its receive queue.xdpw currently doesn't call
sd_bus_get_eventsorsd_bus_get_timeoutat all. This can result in the situation where xdpw goes into apollwith no timeout and a message in sd-bus' receive queue is never handled until another dbus message arrives. I have a case where this ignored messages causes xdg-desktop-portal to hang.This commit changes the polling code to match sd-bus' requirements.
Fixes #281