| 1 | // SPDX-License-Identifier: GPL-2.0 |
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| 2 | // Copyright (c) 2020 Facebook |
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| 3 | #include <linux/bpf.h> |
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| 4 | #include <bpf/bpf_helpers.h> |
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| 5 | #include <bpf/bpf_core_read.h> |
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| 6 | |
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| 7 | struct task_struct { |
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| 8 | int tgid; |
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| 9 | } __attribute__((preserve_access_index)); |
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| 10 | |
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| 11 | struct { |
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| 12 | __uint(type, BPF_MAP_TYPE_ARRAY); |
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| 13 | __uint(max_entries, 1); |
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| 14 | __type(key, int); |
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| 15 | __type(value, int); |
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| 16 | } exp_tgid_map SEC(".maps" ); |
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| 17 | |
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| 18 | struct { |
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| 19 | __uint(type, BPF_MAP_TYPE_ARRAY); |
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| 20 | __uint(max_entries, 1); |
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| 21 | __type(key, int); |
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| 22 | __type(value, int); |
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| 23 | } results SEC(".maps" ); |
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| 24 | |
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| 25 | SEC("tp/raw_syscalls/sys_enter" ) |
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| 26 | int handle_sys_enter(void *ctx) |
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| 27 | { |
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| 28 | struct task_struct *task = (void *)bpf_get_current_task(); |
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| 29 | int tgid = BPF_CORE_READ(task, tgid); |
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| 30 | int zero = 0; |
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| 31 | int real_tgid = bpf_get_current_pid_tgid() >> 32; |
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| 32 | int *exp_tgid = bpf_map_lookup_elem(&exp_tgid_map, &zero); |
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| 33 | |
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| 34 | /* only pass through sys_enters from test process */ |
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| 35 | if (!exp_tgid || *exp_tgid != real_tgid) |
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| 36 | return 0; |
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| 37 | |
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| 38 | bpf_map_update_elem(&results, &zero, &tgid, 0); |
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| 39 | |
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| 40 | return 0; |
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| 41 | } |
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| 42 | |
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| 43 | char _license[] SEC("license" ) = "GPL" ; |
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| 44 | |
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