Commit 1da236b6 authored by Yonghong Song's avatar Yonghong Song Committed by David S. Miller

bpf: add a test case for syscalls/sys_{enter|exit}_* tracepoints

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cf5f5cea
......@@ -39,6 +39,7 @@ hostprogs-y += per_socket_stats_example
hostprogs-y += load_sock_ops
hostprogs-y += xdp_redirect
hostprogs-y += xdp_redirect_map
hostprogs-y += syscall_tp
# Libbpf dependencies
LIBBPF := ../../tools/lib/bpf/bpf.o
......@@ -82,6 +83,7 @@ test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o
per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o
xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o
xdp_redirect_map-objs := bpf_load.o $(LIBBPF) xdp_redirect_map_user.o
syscall_tp-objs := bpf_load.o $(LIBBPF) syscall_tp_user.o
# Tell kbuild to always build the programs
always := $(hostprogs-y)
......@@ -125,6 +127,7 @@ always += tcp_iw_kern.o
always += tcp_clamp_kern.o
always += xdp_redirect_kern.o
always += xdp_redirect_map_kern.o
always += syscall_tp_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include
HOSTCFLAGS += -I$(srctree)/tools/lib/
......@@ -163,6 +166,7 @@ HOSTLOADLIBES_xdp_tx_iptunnel += -lelf
HOSTLOADLIBES_test_map_in_map += -lelf
HOSTLOADLIBES_xdp_redirect += -lelf
HOSTLOADLIBES_xdp_redirect_map += -lelf
HOSTLOADLIBES_syscall_tp += -lelf
# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
......
/* Copyright (c) 2017 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
struct syscalls_enter_open_args {
unsigned long long unused;
long syscall_nr;
long filename_ptr;
long flags;
long mode;
};
struct syscalls_exit_open_args {
unsigned long long unused;
long syscall_nr;
long ret;
};
struct bpf_map_def SEC("maps") enter_open_map = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(u32),
.value_size = sizeof(u32),
.max_entries = 1,
};
struct bpf_map_def SEC("maps") exit_open_map = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(u32),
.value_size = sizeof(u32),
.max_entries = 1,
};
static __always_inline void count(void *map)
{
u32 key = 0;
u32 *value, init_val = 1;
value = bpf_map_lookup_elem(map, &key);
if (value)
*value += 1;
else
bpf_map_update_elem(map, &key, &init_val, BPF_NOEXIST);
}
SEC("tracepoint/syscalls/sys_enter_open")
int trace_enter_open(struct syscalls_enter_open_args *ctx)
{
count((void *)&enter_open_map);
return 0;
}
SEC("tracepoint/syscalls/sys_exit_open")
int trace_enter_exit(struct syscalls_exit_open_args *ctx)
{
count((void *)&exit_open_map);
return 0;
}
/* Copyright (c) 2017 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <linux/bpf.h>
#include <string.h>
#include <linux/perf_event.h>
#include <errno.h>
#include <assert.h>
#include <stdbool.h>
#include <sys/resource.h>
#include "libbpf.h"
#include "bpf_load.h"
/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
* This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
*/
static void verify_map(int map_id)
{
__u32 key = 0;
__u32 val;
if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
return;
}
if (val == 0)
fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
char filename[256];
int fd;
setrlimit(RLIMIT_MEMLOCK, &r);
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (load_bpf_file(filename)) {
fprintf(stderr, "%s", bpf_log_buf);
return 1;
}
/* current load_bpf_file has perf_event_open default pid = -1
* and cpu = 0, which permits attached bpf execution on
* all cpus for all pid's. bpf program execution ignores
* cpu affinity.
*/
/* trigger some "open" operations */
fd = open(filename, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "open failed: %s\n", strerror(errno));
return 1;
}
close(fd);
/* verify the map */
verify_map(map_fd[0]);
verify_map(map_fd[1]);
return 0;
}
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