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fe3300897c
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>
73 lines
1.4 KiB
C
73 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2017 Facebook
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*/
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#include <uapi/linux/bpf.h>
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#include "bpf_helpers.h"
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struct syscalls_enter_open_args {
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unsigned long long unused;
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long syscall_nr;
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long filename_ptr;
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long flags;
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long mode;
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};
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struct syscalls_exit_open_args {
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unsigned long long unused;
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long syscall_nr;
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long ret;
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};
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struct bpf_map_def SEC("maps") enter_open_map = {
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.type = BPF_MAP_TYPE_ARRAY,
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.key_size = sizeof(u32),
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.value_size = sizeof(u32),
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.max_entries = 1,
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};
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struct bpf_map_def SEC("maps") exit_open_map = {
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.type = BPF_MAP_TYPE_ARRAY,
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.key_size = sizeof(u32),
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.value_size = sizeof(u32),
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.max_entries = 1,
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};
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static __always_inline void count(void *map)
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{
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u32 key = 0;
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u32 *value, init_val = 1;
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value = bpf_map_lookup_elem(map, &key);
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if (value)
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*value += 1;
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else
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bpf_map_update_elem(map, &key, &init_val, BPF_NOEXIST);
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}
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SEC("tracepoint/syscalls/sys_enter_open")
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int trace_enter_open(struct syscalls_enter_open_args *ctx)
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{
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count(&enter_open_map);
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return 0;
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}
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SEC("tracepoint/syscalls/sys_enter_openat")
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int trace_enter_open_at(struct syscalls_enter_open_args *ctx)
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{
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count(&enter_open_map);
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return 0;
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}
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SEC("tracepoint/syscalls/sys_exit_open")
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int trace_enter_exit(struct syscalls_exit_open_args *ctx)
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{
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count(&exit_open_map);
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return 0;
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}
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SEC("tracepoint/syscalls/sys_exit_openat")
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int trace_enter_exit_at(struct syscalls_exit_open_args *ctx)
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{
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count(&exit_open_map);
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return 0;
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}
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