Commit 03066ed3 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

selftests/bpf: add read_with_timeout() utility function 



int read_with_timeout(int fd, char *buf, size_t count, long usec)

As a regular read(2), but allows to specify a timeout in
micro-seconds. Returns -EAGAIN on timeout.
Implemented using select().

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20241112110906.3045278-3-eddyz87@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent d9d4d127

tools/testing/selftests/bpf/Makefile

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@@ -742,6 +742,7 @@ TRUNNER_EXTRA_SOURCES := test_progs.c \ 
			 unpriv_helpers.c 	\

			 netlink_helpers.c	\

			 jit_disasm_helpers.c	\

			 io_helpers.c		\

			 test_loader.c		\

			 xsk.c			\

			 disasm.c		\

tools/testing/selftests/bpf/io_helpers.c

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// SPDX-License-Identifier: GPL-2.0

#include <sys/select.h>

#include <unistd.h>

#include <errno.h>



int read_with_timeout(int fd, char *buf, size_t count, long usec)

{

	const long M = 1000 * 1000;

	struct timeval tv = { usec / M, usec % M };

	fd_set fds;

	int err;



	FD_ZERO(&fds);

	FD_SET(fd, &fds);

	err = select(fd + 1, &fds, NULL, NULL, &tv);

	if (err < 0)

		return err;

	if (FD_ISSET(fd, &fds))

		return read(fd, buf, count);

	return -EAGAIN;

}

tools/testing/selftests/bpf/io_helpers.h

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// SPDX-License-Identifier: GPL-2.0

#include <unistd.h>



/* As a regular read(2), but allows to specify a timeout in micro-seconds.

 * Returns -EAGAIN on timeout.

 */

int read_with_timeout(int fd, char *buf, size_t count, long usec);