linux_dsm_epyc7002/samples/bpf/syscall_tp_kern.c
Daniel T. Lee fe3300897c samples: bpf: fix syscall_tp due to unused syscall
Currently, open() is called from the user program and it calls the syscall
'sys_openat', not the 'sys_open'. This leads to an error of the program
of user side, due to the fact that the counter maps are zero since no
function such 'sys_open' is called.

This commit adds the kernel bpf program which are attached to the
tracepoint 'sys_enter_openat' and 'sys_enter_openat'.

Fixes: 1da236b6be ("bpf: add a test case for syscalls/sys_{enter|exit}_* tracepoints")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-12-11 15:28:06 -08:00

74 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
*/
#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(&enter_open_map);
return 0;
}
SEC("tracepoint/syscalls/sys_enter_openat")
int trace_enter_open_at(struct syscalls_enter_open_args *ctx)
{
count(&enter_open_map);
return 0;
}
SEC("tracepoint/syscalls/sys_exit_open")
int trace_enter_exit(struct syscalls_exit_open_args *ctx)
{
count(&exit_open_map);
return 0;
}
SEC("tracepoint/syscalls/sys_exit_openat")
int trace_enter_exit_at(struct syscalls_exit_open_args *ctx)
{
count(&exit_open_map);
return 0;
}