From 30f5836253f820086caa24fc9283344615b8fc00 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Tue, 28 Jul 2020 11:17:00 +0200

Subject: [PATCH] sd-event: add relative timer calls

We frequently want to set a timer relative to the current time. Let's

add an explicit API for this. This not only saves us a few lines of code

everywhere and simplifies things, but also allows us to do correct

overflow checking.

(cherry picked from commit d6a83dc48ad1981665ff427858ae8e59d4cfd6cb)

Related: #2122288

---

 src/libsystemd/libsystemd.sym      |  8 +++++-

 src/libsystemd/sd-event/sd-event.c | 42 ++++++++++++++++++++++++++++++

 src/systemd/sd-event.h             |  2 ++

 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym

index 3b55fc6473..449918093c 100644

--- a/src/libsystemd/libsystemd.sym

+++ b/src/libsystemd/libsystemd.sym

@@ -578,12 +578,18 @@ LIBSYSTEMD_240 {

         sd_bus_get_method_call_timeout;

 } LIBSYSTEMD_239;

+LIBSYSTEMD_247 {

+global:

+        sd_event_add_time_relative;

+        sd_event_source_set_time_relative;

+} LIBSYSTEMD_240;

+

 LIBSYSTEMD_248 {

 global:

         sd_event_source_set_ratelimit;

         sd_event_source_get_ratelimit;

         sd_event_source_is_ratelimited;

-} LIBSYSTEMD_240;

+} LIBSYSTEMD_247;

 LIBSYSTEMD_250 {

 global:

diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c

index 09d4584bf9..2c9d331bf2 100644

--- a/src/libsystemd/sd-event/sd-event.c

+++ b/src/libsystemd/sd-event/sd-event.c

@@ -1415,6 +1415,31 @@ fail:

         return r;

 }

+_public_ int sd_event_add_time_relative(

+                sd_event *e,

+                sd_event_source **ret,

+                clockid_t clock,

+                uint64_t usec,

+                uint64_t accuracy,

+                sd_event_time_handler_t callback,

+                void *userdata) {

+

+        usec_t t;

+        int r;

+

+        /* Same as sd_event_add_time() but operates relative to the event loop's current point in time, and

+         * checks for overflow. */

+

+        r = sd_event_now(e, clock, &t);

+        if (r < 0)

+                return r;

+

+        if (usec >= USEC_INFINITY - t)

+                return -EOVERFLOW;

+

+        return sd_event_add_time(e, ret, clock, t + usec, accuracy, callback, userdata);

+}

+

 static int signal_exit_callback(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {

         assert(s);

@@ -2578,6 +2603,23 @@ _public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) {

         return 0;

 }

+_public_ int sd_event_source_set_time_relative(sd_event_source *s, uint64_t usec) {

+        usec_t t;

+        int r;

+

+        assert_return(s, -EINVAL);

+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);

+

+        r = sd_event_now(s->event, event_source_type_to_clock(s->type), &t);

+        if (r < 0)

+                return r;

+

+        if (usec >= USEC_INFINITY - t)

+                return -EOVERFLOW;

+

+        return sd_event_source_set_time(s, t + usec);

+}

+

 _public_ int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *usec) {

         assert_return(s, -EINVAL);

         assert_return(usec, -EINVAL);

diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h

index c2e9c9614d..960bea1ac4 100644

--- a/src/systemd/sd-event.h

+++ b/src/systemd/sd-event.h

@@ -87,6 +87,7 @@ sd_event* sd_event_unref(sd_event *e);

 int sd_event_add_io(sd_event *e, sd_event_source **s, int fd, uint32_t events, sd_event_io_handler_t callback, void *userdata);

 int sd_event_add_time(sd_event *e, sd_event_source **s, clockid_t clock, uint64_t usec, uint64_t accuracy, sd_event_time_handler_t callback, void *userdata);

+int sd_event_add_time_relative(sd_event *e, sd_event_source **s, clockid_t clock, uint64_t usec, uint64_t accuracy, sd_event_time_handler_t callback, void *userdata);

 int sd_event_add_signal(sd_event *e, sd_event_source **s, int sig, sd_event_signal_handler_t callback, void *userdata);

 int sd_event_add_child(sd_event *e, sd_event_source **s, pid_t pid, int options, sd_event_child_handler_t callback, void *userdata);

 int sd_event_add_inotify(sd_event *e, sd_event_source **s, const char *path, uint32_t mask, sd_event_inotify_handler_t callback, void *userdata);

@@ -136,6 +137,7 @@ int sd_event_source_set_io_events(sd_event_source *s, uint32_t events);

 int sd_event_source_get_io_revents(sd_event_source *s, uint32_t* revents);

 int sd_event_source_get_time(sd_event_source *s, uint64_t *usec);

 int sd_event_source_set_time(sd_event_source *s, uint64_t usec);

+int sd_event_source_set_time_relative(sd_event_source *s, uint64_t usec);

 int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *usec);

 int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec);

 int sd_event_source_get_time_clock(sd_event_source *s, clockid_t *clock);