mirror of
https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git
synced 2026-10-24 00:48:53 +03:00
92f7ecc1d1
gpiod_edge_event_buffer_read_fd() is documented to read at most
max_events events and to return the number of events read. When called
with max_events == 0 it nonetheless issued a read() for 0 bytes, which
returns 0, and the subsequent short-read check
((unsigned int)rd < sizeof(*event_data)) then treated this as an I/O
error, setting errno to EIO and returning -1.
Requesting zero events is not an error - it is a no-op that reads
nothing. Handle it explicitly by clearing num_events and returning 0
before attempting the read.
Add a test case verifying the behavior.
Fixes: b7ba732e6a ("treewide: libgpiod v2 implementation")
Assisted-by: Claude Opus 4.8
Link: https://patch.msgid.link/20260608-more-pre-2-3-fixes-v1-2-577a5ba426a5@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>