1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ 3 4 #include "vmlinux.h" 5 #include <bpf/bpf_helpers.h> 6 #include <bpf/bpf_tracing.h> 7 8 char _license[] SEC("license") = "GPL"; 9 10 struct { 11 __uint(type, BPF_MAP_TYPE_CGRP_STORAGE); 12 __uint(map_flags, BPF_F_NO_PREALLOC); 13 __type(key, int); 14 __type(value, long); 15 } map_a SEC(".maps"); 16 17 struct { 18 __uint(type, BPF_MAP_TYPE_CGRP_STORAGE); 19 __uint(map_flags, BPF_F_NO_PREALLOC); 20 __type(key, int); 21 __type(value, long); 22 } map_b SEC(".maps"); 23 24 #define MAGIC_VALUE 0xabcd1234 25 26 pid_t target_pid = 0; 27 int mismatch_cnt = 0; 28 int enter_cnt = 0; 29 int exit_cnt = 0; 30 int target_hid = 0; 31 bool is_cgroup1 = 0; 32 33 struct cgroup *bpf_task_get_cgroup1(struct task_struct *task, int hierarchy_id) __ksym; 34 void bpf_cgroup_release(struct cgroup *cgrp) __ksym; 35 36 static void __on_enter(struct pt_regs *regs, long id, struct cgroup *cgrp) 37 { 38 long *ptr; 39 int err; 40 41 /* populate value 0 */ 42 ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, 43 BPF_LOCAL_STORAGE_GET_F_CREATE); 44 if (!ptr) 45 return; 46 47 /* delete value 0 */ 48 err = bpf_cgrp_storage_delete(&map_a, cgrp); 49 if (err) 50 return; 51 52 /* value is not available */ 53 ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, 0); 54 if (ptr) 55 return; 56 57 /* re-populate the value */ 58 ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, 59 BPF_LOCAL_STORAGE_GET_F_CREATE); 60 if (!ptr) 61 return; 62 __sync_fetch_and_add(&enter_cnt, 1); 63 *ptr = MAGIC_VALUE + enter_cnt; 64 } 65 66 SEC("tp_btf/sys_enter") 67 int BPF_PROG(on_enter, struct pt_regs *regs, long id) 68 { 69 struct task_struct *task; 70 struct cgroup *cgrp; 71 72 task = bpf_get_current_task_btf(); 73 if (task->pid != target_pid) 74 return 0; 75 76 if (is_cgroup1) { 77 cgrp = bpf_task_get_cgroup1(task, target_hid); 78 if (!cgrp) 79 return 0; 80 81 __on_enter(regs, id, cgrp); 82 bpf_cgroup_release(cgrp); 83 return 0; 84 } 85 86 __on_enter(regs, id, task->cgroups->dfl_cgrp); 87 return 0; 88 } 89 90 static void __on_exit(struct pt_regs *regs, long id, struct cgroup *cgrp) 91 { 92 long *ptr; 93 94 ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, 95 BPF_LOCAL_STORAGE_GET_F_CREATE); 96 if (!ptr) 97 return; 98 99 __sync_fetch_and_add(&exit_cnt, 1); 100 if (*ptr != MAGIC_VALUE + exit_cnt) 101 __sync_fetch_and_add(&mismatch_cnt, 1); 102 } 103 104 SEC("tp_btf/sys_exit") 105 int BPF_PROG(on_exit, struct pt_regs *regs, long id) 106 { 107 struct task_struct *task; 108 struct cgroup *cgrp; 109 110 task = bpf_get_current_task_btf(); 111 if (task->pid != target_pid) 112 return 0; 113 114 if (is_cgroup1) { 115 cgrp = bpf_task_get_cgroup1(task, target_hid); 116 if (!cgrp) 117 return 0; 118 119 __on_exit(regs, id, cgrp); 120 bpf_cgroup_release(cgrp); 121 return 0; 122 } 123 124 __on_exit(regs, id, task->cgroups->dfl_cgrp); 125 return 0; 126 } 127