GNU Linux-libre 6.6.15-gnu
[releases.git] / samples / bpf / offwaketime_user.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
3  */
4 #include <stdio.h>
5 #include <unistd.h>
6 #include <stdlib.h>
7 #include <signal.h>
8 #include <linux/perf_event.h>
9 #include <errno.h>
10 #include <stdbool.h>
11 #include <bpf/libbpf.h>
12 #include <bpf/bpf.h>
13 #include "trace_helpers.h"
14
15 #define PRINT_RAW_ADDR 0
16
17 /* counts, stackmap */
18 static int map_fd[2];
19
20 static void print_ksym(__u64 addr)
21 {
22         struct ksym *sym;
23
24         if (!addr)
25                 return;
26         sym = ksym_search(addr);
27         if (!sym) {
28                 printf("ksym not found. Is kallsyms loaded?\n");
29                 return;
30         }
31
32         if (PRINT_RAW_ADDR)
33                 printf("%s/%llx;", sym->name, addr);
34         else
35                 printf("%s;", sym->name);
36 }
37
38 #define TASK_COMM_LEN 16
39
40 struct key_t {
41         char waker[TASK_COMM_LEN];
42         char target[TASK_COMM_LEN];
43         __u32 wret;
44         __u32 tret;
45 };
46
47 static void print_stack(struct key_t *key, __u64 count)
48 {
49         __u64 ip[PERF_MAX_STACK_DEPTH] = {};
50         static bool warned;
51         int i;
52
53         printf("%s;", key->target);
54         if (bpf_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {
55                 printf("---;");
56         } else {
57                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
58                         print_ksym(ip[i]);
59         }
60         printf("-;");
61         if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {
62                 printf("---;");
63         } else {
64                 for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
65                         print_ksym(ip[i]);
66         }
67         printf(";%s %lld\n", key->waker, count);
68
69         if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) {
70                 printf("stackmap collisions seen. Consider increasing size\n");
71                 warned = true;
72         } else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) {
73                 printf("err stackid %d %d\n", key->tret, key->wret);
74         }
75 }
76
77 static void print_stacks(int fd)
78 {
79         struct key_t key = {}, next_key;
80         __u64 value;
81
82         while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
83                 bpf_map_lookup_elem(fd, &next_key, &value);
84                 print_stack(&next_key, value);
85                 key = next_key;
86         }
87 }
88
89 static void int_exit(int sig)
90 {
91         print_stacks(map_fd[0]);
92         exit(0);
93 }
94
95 int main(int argc, char **argv)
96 {
97         struct bpf_object *obj = NULL;
98         struct bpf_link *links[2];
99         struct bpf_program *prog;
100         int delay = 1, i = 0;
101         char filename[256];
102
103         if (load_kallsyms()) {
104                 printf("failed to process /proc/kallsyms\n");
105                 return 2;
106         }
107
108         snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
109         obj = bpf_object__open_file(filename, NULL);
110         if (libbpf_get_error(obj)) {
111                 fprintf(stderr, "ERROR: opening BPF object file failed\n");
112                 obj = NULL;
113                 goto cleanup;
114         }
115
116         /* load BPF program */
117         if (bpf_object__load(obj)) {
118                 fprintf(stderr, "ERROR: loading BPF object file failed\n");
119                 goto cleanup;
120         }
121
122         map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
123         map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
124         if (map_fd[0] < 0 || map_fd[1] < 0) {
125                 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
126                 goto cleanup;
127         }
128
129         signal(SIGINT, int_exit);
130         signal(SIGTERM, int_exit);
131
132         bpf_object__for_each_program(prog, obj) {
133                 links[i] = bpf_program__attach(prog);
134                 if (libbpf_get_error(links[i])) {
135                         fprintf(stderr, "ERROR: bpf_program__attach failed\n");
136                         links[i] = NULL;
137                         goto cleanup;
138                 }
139                 i++;
140         }
141
142         if (argc > 1)
143                 delay = atoi(argv[1]);
144         sleep(delay);
145         print_stacks(map_fd[0]);
146
147 cleanup:
148         for (i--; i >= 0; i--)
149                 bpf_link__destroy(links[i]);
150
151         bpf_object__close(obj);
152         return 0;
153 }