So far, the only way to implement periodic interval timers was to use
one-shot uloop_timeout timers which are rearmed within their completion
callback immediately on expiration.
While simple, this approach is not very precise and interval lengths will
slowly drift over time, due to callback execution overhead, scheduling
granularity etc.
In order to make uloop provide stable and precise interval timer
capabilities, this commit introduces a new `uloop_interval` structure
along with the new related `uloop_interval_set()`, `uloop_interval_cancel()`
and `uloop_interval_remaining()` api functions.
Periodic timers are implemented using the timerfd facility an Linux and
kqueue EVFILT_TIMER events on macOS/BSD.
The Lua binding has been updated to include support for the new timer type
as well.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
- support reading the next timeout in order to determine the poll timeout
- add a callback for fd add/delete/update
Signed-off-by: Felix Fietkau <nbd@nbd.name>
This uses the same return type as tv_diff so we don't need to check for
integer overflow.
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Acked-by: Jo-Philipp Wich <jo@mein.io>
Acked-by: John Crispin <john@phrozen.org>
The uloop_timeout_remaining function is public and changing its return
type breaks ABI. Change the return type back to int, and return INT_MIN
or INT_MAX if the value returned by tv_diff would overflow integer.
Fixes: be3dc7223a ("uloop: avoid integer overflow in tv_diff")
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Acked-by: Jo-Philipp Wich <jo@mein.io>
Acked-by: John Crispin <john@phrozen.org>
The tv_diff function can potentially overflow as soon as t2->tv_sec is
larger than 2147483. This is very easily hit in ujail, after only
2147484 seconds of uptime, or 24.85 days.
Improve the behaviour by changing the return type to int64_t.
Fixes: FS#3943
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
This can be useful for cleanup with pending timers, or for hooking into
existing code that does not use uloop
Signed-off-by: Felix Fietkau <nbd@nbd.name>
When a process quits in response to a signal it handles, it should to so
be re-sending the signal to itself. This especially important for SIGINT,
as is explained in [1].
uloop currently hides the reason for quitting uloop_run(). Fix this by
returning the signal that caused the loop to quit (or 0 when uloop_end()
was used), so a program using loop an comply with [1].
[1] https://www.cons.org/cracauer/sigint.html
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
In some conditions, an application is interested in errors happening
on a file descriptor and might be able to resolve the issue in the
callback function.
This patch adds a flag to notify the uloop framework that errors
should be passed to the callback function, instead of silently
removing the fd from the polling set.
Signed-off-by: Karl Vogel <karl.vogel@gmail.com>
With multiple recursive calls to uloop_run, the callback for the same fd
can be run multiple times from different levels in the stack.
Prevent this by tracking the stack of uloop_fd callbacks and buffering new
incoming events for fds already on the stack.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Sometimes after re-arming a fd, an initial event for reads is not generated,
even though there is data pending. Work around this by making the trigger
level-triggered first, then switching to edge trigger after processing the first
event.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
