Commit 92dc5cdf authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
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selftests/bpf: Add 6-argument syscall tracing test 



Turns out splice() is one of the syscalls that's using current maximum
number of arguments (six). This is perfect for testing, so extend
bpf_syscall_macro selftest to also trace splice() syscall, using
BPF_KSYSCALL() macro. This makes sure all the syscall argument register
definitions are correct.

Suggested-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Tested-by: Alan Maguire <alan.maguire@oracle.com> # arm64
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> # s390x
Link: https://lore.kernel.org/bpf/20230120200914.3008030-25-andrii@kernel.org
parent 12a299f0

tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c

+17 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright 2022 Sony Group Corporation */

#define _GNU_SOURCE

#include <fcntl.h>

#include <sys/prctl.h>

#include <test_progs.h>

#include "bpf_syscall_macro.skel.h"
@@ -13,6 +15,8 @@ void test_bpf_syscall_macro(void) 
	unsigned long exp_arg3 = 13;

	unsigned long exp_arg4 = 14;

	unsigned long exp_arg5 = 15;

	loff_t off_in, off_out;

	ssize_t r;



	/* check whether it can open program */

	skel = bpf_syscall_macro__open();
@@ -33,6 +37,7 @@ void test_bpf_syscall_macro(void) 


	/* check whether args of syscall are copied correctly */

	prctl(exp_arg1, exp_arg2, exp_arg3, exp_arg4, exp_arg5);



#if defined(__aarch64__) || defined(__s390__)

	ASSERT_NEQ(skel->bss->arg1, exp_arg1, "syscall_arg1");

#else
@@ -68,6 +73,18 @@ void test_bpf_syscall_macro(void) 
	ASSERT_EQ(skel->bss->arg4_syscall, exp_arg4, "BPF_KPROBE_SYSCALL_arg4");

	ASSERT_EQ(skel->bss->arg5_syscall, exp_arg5, "BPF_KPROBE_SYSCALL_arg5");



	r = splice(-42, &off_in, 42, &off_out, 0x12340000, SPLICE_F_NONBLOCK);

	err = -errno;

	ASSERT_EQ(r, -1, "splice_res");

	ASSERT_EQ(err, -EBADF, "splice_err");



	ASSERT_EQ(skel->bss->splice_fd_in, -42, "splice_arg1");

	ASSERT_EQ(skel->bss->splice_off_in, (__u64)&off_in, "splice_arg2");

	ASSERT_EQ(skel->bss->splice_fd_out, 42, "splice_arg3");

	ASSERT_EQ(skel->bss->splice_off_out, (__u64)&off_out, "splice_arg4");

	ASSERT_EQ(skel->bss->splice_len, 0x12340000, "splice_arg5");

	ASSERT_EQ(skel->bss->splice_flags, SPLICE_F_NONBLOCK, "splice_arg6");



cleanup:

	bpf_syscall_macro__destroy(skel);

}

tools/testing/selftests/bpf/progs/bpf_syscall_macro.c

+26 −0
Original line number Diff line number Diff line
@@ -81,4 +81,30 @@ int BPF_KSYSCALL(prctl_enter, int option, unsigned long arg2, 
	return 0;

}



__u64 splice_fd_in;

__u64 splice_off_in;

__u64 splice_fd_out;

__u64 splice_off_out;

__u64 splice_len;

__u64 splice_flags;



SEC("ksyscall/splice")

int BPF_KSYSCALL(splice_enter, int fd_in, loff_t *off_in, int fd_out,

		 loff_t *off_out, size_t len, unsigned int flags)

{

	pid_t pid = bpf_get_current_pid_tgid() >> 32;



	if (pid != filter_pid)

		return 0;



	splice_fd_in = fd_in;

	splice_off_in = (__u64)off_in;

	splice_fd_out = fd_out;

	splice_off_out = (__u64)off_out;

	splice_len = len;

	splice_flags = flags;



	return 0;

}



char _license[] SEC("license") = "GPL";