1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ 3 4 #ifndef _CGRP_KFUNC_COMMON_H 5 #define _CGRP_KFUNC_COMMON_H 6 7 #include <errno.h> 8 #include <vmlinux.h> 9 #include <bpf/bpf_helpers.h> 10 #include <bpf/bpf_tracing.h> 11 12 struct __cgrps_kfunc_map_value { 13 struct cgroup __kptr * cgrp; 14 }; 15 16 struct { 17 __uint(type, BPF_MAP_TYPE_HASH); 18 __type(key, int); 19 __type(value, struct __cgrps_kfunc_map_value); 20 __uint(max_entries, 1); 21 } __cgrps_kfunc_map SEC(".maps"); 22 23 struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; 24 void bpf_cgroup_release(struct cgroup *p) __ksym; 25 struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym; 26 struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; 27 void bpf_rcu_read_lock(void) __ksym; 28 void bpf_rcu_read_unlock(void) __ksym; 29 30 static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp) 31 { 32 s32 id; 33 long status; 34 35 status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id); 36 if (status) 37 return NULL; 38 39 return bpf_map_lookup_elem(&__cgrps_kfunc_map, &id); 40 } 41 42 static inline int cgrps_kfunc_map_insert(struct cgroup *cgrp) 43 { 44 struct __cgrps_kfunc_map_value local, *v; 45 long status; 46 struct cgroup *acquired, *old; 47 s32 id; 48 49 status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id); 50 if (status) 51 return status; 52 53 local.cgrp = NULL; 54 status = bpf_map_update_elem(&__cgrps_kfunc_map, &id, &local, BPF_NOEXIST); 55 if (status) 56 return status; 57 58 v = bpf_map_lookup_elem(&__cgrps_kfunc_map, &id); 59 if (!v) { 60 bpf_map_delete_elem(&__cgrps_kfunc_map, &id); 61 return -ENOENT; 62 } 63 64 acquired = bpf_cgroup_acquire(cgrp); 65 if (!acquired) { 66 bpf_map_delete_elem(&__cgrps_kfunc_map, &id); 67 return -ENOENT; 68 } 69 70 old = bpf_kptr_xchg(&v->cgrp, acquired); 71 if (old) { 72 bpf_cgroup_release(old); 73 return -EEXIST; 74 } 75 76 return 0; 77 } 78 79 #endif /* _CGRP_KFUNC_COMMON_H */ 80