Leo Stone wrote:
> Make pair_udp_send_char handle EAGAIN, EINTR, and partial reads or
> writes.
>
> Signed-off-by: Leo Stone <leocstone@xxxxxxxxx>
Did you observe actual issues or is this based on the comment in the
existing code ("Should really handle EINTR and EAGAIN").
AFAIK all the users of psock_lib use default blocking IO, so should
not see EAGAIN.
A simpler approach to dealing with EINTR is to ask glibc to restart
with sigaction or siginterrupt.
> ---
> tools/testing/selftests/net/psock_lib.h | 39 +++++++++++++++++++------
> 1 file changed, 30 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/net/psock_lib.h b/tools/testing/selftests/net/psock_lib.h
> index 6e4fef560873..e28bff95c8e2 100644
> --- a/tools/testing/selftests/net/psock_lib.h
> +++ b/tools/testing/selftests/net/psock_lib.h
> @@ -13,6 +13,7 @@
> #include <string.h>
> #include <arpa/inet.h>
> #include <unistd.h>
> +#include <stdbool.h>
>
> #include "kselftest.h"
>
> @@ -110,21 +111,41 @@ static __maybe_unused void pair_udp_open(int fds[], uint16_t port)
> }
> }
>
> +static void read_write_checked(int fd, char *buf, size_t sz, bool is_write)
> +{
> + int bytes_processed = 0;
> + int ret;
> +
> + do {
> + if (is_write)
> + ret = write(fd, buf + bytes_processed,
> + sz - bytes_processed);
> + else
> + ret = read(fd, buf + bytes_processed,
> + sz - bytes_processed);
> + if (ret == -1) {
> + if (errno == EAGAIN || errno == EINTR) {
> + continue;
Instead of busy looping, on return with EAGAIN should probably block.
> + } else {
> + fprintf(stderr, "ERROR: %s failed, bytes left=%lu\n",
> + is_write ? "send" : "recv",
> + sz - bytes_processed);
> + exit(1);
> + }
> + }
> + bytes_processed += ret;
> + } while (bytes_processed < sz);
> +}
> +
> static __maybe_unused void pair_udp_send_char(int fds[], int num, char payload)
> {
> char buf[DATA_LEN], rbuf[DATA_LEN];
>
> memset(buf, payload, sizeof(buf));
> while (num--) {
> - /* Should really handle EINTR and EAGAIN */
> - if (write(fds[0], buf, sizeof(buf)) != sizeof(buf)) {
> - fprintf(stderr, "ERROR: send failed left=%d\n", num);
> - exit(1);
> - }
> - if (read(fds[1], rbuf, sizeof(rbuf)) != sizeof(rbuf)) {
> - fprintf(stderr, "ERROR: recv failed left=%d\n", num);
> - exit(1);
> - }
> + read_write_checked(fds[0], buf, sizeof(buf), true);
> + read_write_checked(fds[1], rbuf, sizeof(rbuf), false);
> +
> if (memcmp(buf, rbuf, sizeof(buf))) {
> fprintf(stderr, "ERROR: data failed left=%d\n", num);
> exit(1);
> --
> 2.39.5
>
