sd-bus: handle -EINTR return from bus_poll()

In sd_bus_wait(), let's convert EINTR to a return code of 0, thus asking
the caller do loop again and enter sd_bus_process() again (which will
not find any queued events). This way we'll not return an error on
something that isn't really an error. This should typically make sure
things are properly handled by the caller, magically, without eating up
the event entirely, and still giving the caller time to run some code if
they want.

2 files changed, 19 insertions, 4 deletions

diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index c94befef73..253f41c636 100644
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -1308,8 +1308,11 @@ int bus_socket_process_opening(sd_bus *b) {
         assert(b->state == BUS_OPENING);
 
         events = fd_wait_for_event(b->output_fd, POLLOUT, 0);
-        if (events < 0)
+        if (events < 0) {
+                if (ERRNO_IS_TRANSIENT(events))
+                        return 0;
                 return events;
+        }
         if (!(events & (POLLOUT|POLLERR|POLLHUP)))
                 return 0;
 
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index ba5ef7de00..c75276f4ba 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -2465,8 +2465,11 @@ _public_ int sd_bus_call(
                         left = UINT64_MAX;
 
                 r = bus_poll(bus, true, left);
-                if (r < 0)
+                if (r < 0) {
+                        if (ERRNO_IS_TRANSIENT(r))
+                                continue;
                         goto fail;
+                }
                 if (r == 0) {
                         r = -ETIMEDOUT;
                         goto fail;
@@ -3321,6 +3324,7 @@ static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec) {
 }
 
 _public_ int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
+        int r;
 
         assert_return(bus, -EINVAL);
         assert_return(bus = bus_resolve(bus), -ENOPKG);
@@ -3335,7 +3339,11 @@ _public_ int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
         if (bus->rqueue_size > 0)
                 return 0;
 
-        return bus_poll(bus, false, timeout_usec);
+        r = bus_poll(bus, false, timeout_usec);
+        if (r < 0 && ERRNO_IS_TRANSIENT(r))
+                return 1; /* treat EINTR as success, but let's exit, so that the caller will call back into us soon. */
+
+        return r;
 }
 
 _public_ int sd_bus_flush(sd_bus *bus) {
@@ -3377,8 +3385,12 @@ _public_ int sd_bus_flush(sd_bus *bus) {
                         return 0;
 
                 r = bus_poll(bus, false, UINT64_MAX);
-                if (r < 0)
+                if (r < 0) {
+                        if (ERRNO_IS_TRANSIENT(r))
+                                continue;
+
                         return r;
+                }
         }
 }