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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2020 Facebook */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_tracing.h>
#include "pid_iter.h"
/* keep in sync with the definition in main.h */
enum bpf_obj_type {
BPF_OBJ_UNKNOWN,
BPF_OBJ_PROG,
BPF_OBJ_MAP,
BPF_OBJ_LINK,
BPF_OBJ_BTF,
};
struct bpf_perf_link___local {
struct bpf_link link;
struct file *perf_file;
} __attribute__((preserve_access_index));
struct perf_event___local {
u64 bpf_cookie;
} __attribute__((preserve_access_index));
enum bpf_link_type___local {
BPF_LINK_TYPE_PERF_EVENT___local = 7,
};
extern const void bpf_link_fops __ksym;
extern const void bpf_link_fops_poll __ksym __weak;
extern const void bpf_map_fops __ksym;
extern const void bpf_prog_fops __ksym;
extern const void btf_fops __ksym;
const volatile enum bpf_obj_type obj_type = BPF_OBJ_UNKNOWN;
static __always_inline __u32 get_obj_id(void *ent, enum bpf_obj_type type)
{
switch (type) {
case BPF_OBJ_PROG:
return BPF_CORE_READ((struct bpf_prog *)ent, aux, id);
case BPF_OBJ_MAP:
return BPF_CORE_READ((struct bpf_map *)ent, id);
case BPF_OBJ_BTF:
return BPF_CORE_READ((struct btf *)ent, id);
case BPF_OBJ_LINK:
return BPF_CORE_READ((struct bpf_link *)ent, id);
default:
return 0;
}
}
/* could be used only with BPF_LINK_TYPE_PERF_EVENT links */
static __u64 get_bpf_cookie(struct bpf_link *link)
{
struct bpf_perf_link___local *perf_link;
struct perf_event___local *event;
perf_link = container_of(link, struct bpf_perf_link___local, link);
event = BPF_CORE_READ(perf_link, perf_file, private_data);
return BPF_CORE_READ(event, bpf_cookie);
}
SEC("iter/task_file")
int iter(struct bpf_iter__task_file *ctx)
{
struct file *file = ctx->file;
struct task_struct *task = ctx->task;
struct pid_iter_entry e;
const void *fops;
if (!file || !task)
return 0;
switch (obj_type) {
case BPF_OBJ_PROG:
fops = &bpf_prog_fops;
break;
case BPF_OBJ_MAP:
fops = &bpf_map_fops;
break;
case BPF_OBJ_BTF:
fops = &btf_fops;
break;
case BPF_OBJ_LINK:
if (&bpf_link_fops_poll &&
file->f_op == &bpf_link_fops_poll)
fops = &bpf_link_fops_poll;
else
fops = &bpf_link_fops;
break;
default:
return 0;
}
if (file->f_op != fops)
return 0;
__builtin_memset(&e, 0, sizeof(e));
e.pid = task->tgid;
e.id = get_obj_id(file->private_data, obj_type);
if (obj_type == BPF_OBJ_LINK &&
bpf_core_enum_value_exists(enum bpf_link_type___local,
BPF_LINK_TYPE_PERF_EVENT___local)) {
struct bpf_link *link = (struct bpf_link *) file->private_data;
if (BPF_CORE_READ(link, type) == bpf_core_enum_value(enum bpf_link_type___local,
BPF_LINK_TYPE_PERF_EVENT___local)) {
e.has_bpf_cookie = true;
e.bpf_cookie = get_bpf_cookie(link);
}
}
bpf_probe_read_kernel_str(&e.comm, sizeof(e.comm),
task->group_leader->comm);
bpf_seq_write(ctx->meta->seq, &e, sizeof(e));
return 0;
}
char LICENSE[] SEC("license") = "Dual BSD/GPL";
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