/* SPDX-License-Identifier: GPL-2.0 */ /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ #ifndef _TASK_KFUNC_COMMON_H #define _TASK_KFUNC_COMMON_H #include <errno.h> #include <vmlinux.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> struct __tasks_kfunc_map_value { struct task_struct __kptr * task; }; struct { __uint(type, BPF_MAP_TYPE_HASH); __type(key, int); __type(value, struct __tasks_kfunc_map_value); __uint(max_entries, 1); } __tasks_kfunc_map SEC(".maps"); struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; void bpf_task_release(struct task_struct *p) __ksym; struct task_struct *bpf_task_from_pid(s32 pid) __ksym; void bpf_rcu_read_lock(void) __ksym; void bpf_rcu_read_unlock(void) __ksym; static inline struct __tasks_kfunc_map_value *tasks_kfunc_map_value_lookup(struct task_struct *p) { s32 pid; long status; status = bpf_probe_read_kernel(&pid, sizeof(pid), &p->pid); if (status) return NULL; return bpf_map_lookup_elem(&__tasks_kfunc_map, &pid); } static inline int tasks_kfunc_map_insert(struct task_struct *p) { struct __tasks_kfunc_map_value local, *v; long status; struct task_struct *acquired, *old; s32 pid; status = bpf_probe_read_kernel(&pid, sizeof(pid), &p->pid); if (status) return status; local.task = NULL; status = bpf_map_update_elem(&__tasks_kfunc_map, &pid, &local, BPF_NOEXIST); if (status) return status; v = bpf_map_lookup_elem(&__tasks_kfunc_map, &pid); if (!v) { bpf_map_delete_elem(&__tasks_kfunc_map, &pid); return -ENOENT; } acquired = bpf_task_acquire(p); if (!acquired) return -ENOENT; old = bpf_kptr_xchg(&v->task, acquired); if (old) { bpf_task_release(old); return -EEXIST; } return 0; } #endif /* _TASK_KFUNC_COMMON_H */