linux/samples/bpf/syscall_tp_kern.c
Daniel T. Lee f0c328f8af samples: bpf: Refactor tracepoint tracing programs with libbpf
For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing tracepoint tracing programs with libbbpf
bpf loader.

    - Adding a tracepoint event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-4-danieltimlee@gmail.com
2020-08-24 20:59:35 -07:00

73 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
*/
#include <uapi/linux/bpf.h>
#include <bpf/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 {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, u32);
__uint(max_entries, 1);
} enter_open_map SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, u32);
__uint(max_entries, 1);
} exit_open_map SEC(".maps");
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;
}