1 // SPDX-License-Identifier: GPL-2.0
2 #include <stdio.h>
3 #include <unistd.h>
4 #include <stdlib.h>
5 #include <signal.h>
6 #include <string.h>
7 #include <sys/resource.h>
8
9 #include <bpf/bpf.h>
10 #include <bpf/libbpf.h>
11 #include "bpf_util.h"
12
13 #define MAX_INDEX 64
14 #define MAX_STARS 38
15
16 /* my_map, my_hist_map */
17 static int map_fd[2];
18
stars(char * str,long val,long max,int width)19 static void stars(char *str, long val, long max, int width)
20 {
21 int i;
22
23 for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
24 str[i] = '*';
25 if (val > max)
26 str[i - 1] = '+';
27 str[i] = '\0';
28 }
29
30 struct task {
31 char comm[16];
32 __u64 pid_tgid;
33 __u64 uid_gid;
34 };
35
36 struct hist_key {
37 struct task t;
38 __u32 index;
39 };
40
41 #define SIZE sizeof(struct task)
42
print_hist_for_pid(int fd,void * task)43 static void print_hist_for_pid(int fd, void *task)
44 {
45 unsigned int nr_cpus = bpf_num_possible_cpus();
46 struct hist_key key = {}, next_key;
47 long values[nr_cpus];
48 char starstr[MAX_STARS];
49 long value;
50 long data[MAX_INDEX] = {};
51 int max_ind = -1;
52 long max_value = 0;
53 int i, ind;
54
55 while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
56 if (memcmp(&next_key, task, SIZE)) {
57 key = next_key;
58 continue;
59 }
60 bpf_map_lookup_elem(fd, &next_key, values);
61 value = 0;
62 for (i = 0; i < nr_cpus; i++)
63 value += values[i];
64 ind = next_key.index;
65 data[ind] = value;
66 if (value && ind > max_ind)
67 max_ind = ind;
68 if (value > max_value)
69 max_value = value;
70 key = next_key;
71 }
72
73 printf(" syscall write() stats\n");
74 printf(" byte_size : count distribution\n");
75 for (i = 1; i <= max_ind + 1; i++) {
76 stars(starstr, data[i - 1], max_value, MAX_STARS);
77 printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
78 (1l << i) >> 1, (1l << i) - 1, data[i - 1],
79 MAX_STARS, starstr);
80 }
81 }
82
print_hist(int fd)83 static void print_hist(int fd)
84 {
85 struct hist_key key = {}, next_key;
86 static struct task tasks[1024];
87 int task_cnt = 0;
88 int i;
89
90 while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
91 int found = 0;
92
93 for (i = 0; i < task_cnt; i++)
94 if (memcmp(&tasks[i], &next_key, SIZE) == 0)
95 found = 1;
96 if (!found)
97 memcpy(&tasks[task_cnt++], &next_key, SIZE);
98 key = next_key;
99 }
100
101 for (i = 0; i < task_cnt; i++) {
102 printf("\npid %d cmd %s uid %d\n",
103 (__u32) tasks[i].pid_tgid,
104 tasks[i].comm,
105 (__u32) tasks[i].uid_gid);
106 print_hist_for_pid(fd, &tasks[i]);
107 }
108
109 }
110
int_exit(int sig)111 static void int_exit(int sig)
112 {
113 print_hist(map_fd[1]);
114 exit(0);
115 }
116
main(int ac,char ** argv)117 int main(int ac, char **argv)
118 {
119 long key, next_key, value;
120 struct bpf_link *links[2];
121 struct bpf_program *prog;
122 struct bpf_object *obj;
123 char filename[256];
124 int i, j = 0;
125 FILE *f;
126
127 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
128 obj = bpf_object__open_file(filename, NULL);
129 if (libbpf_get_error(obj)) {
130 fprintf(stderr, "ERROR: opening BPF object file failed\n");
131 return 0;
132 }
133
134 /* load BPF program */
135 if (bpf_object__load(obj)) {
136 fprintf(stderr, "ERROR: loading BPF object file failed\n");
137 goto cleanup;
138 }
139
140 map_fd[0] = bpf_object__find_map_fd_by_name(obj, "my_map");
141 map_fd[1] = bpf_object__find_map_fd_by_name(obj, "my_hist_map");
142 if (map_fd[0] < 0 || map_fd[1] < 0) {
143 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
144 goto cleanup;
145 }
146
147 signal(SIGINT, int_exit);
148 signal(SIGTERM, int_exit);
149
150 /* start 'ping' in the background to have some kfree_skb events */
151 f = popen("ping -4 -c5 localhost", "r");
152 (void) f;
153
154 /* start 'dd' in the background to have plenty of 'write' syscalls */
155 f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r");
156 (void) f;
157
158 bpf_object__for_each_program(prog, obj) {
159 links[j] = bpf_program__attach(prog);
160 if (libbpf_get_error(links[j])) {
161 fprintf(stderr, "ERROR: bpf_program__attach failed\n");
162 links[j] = NULL;
163 goto cleanup;
164 }
165 j++;
166 }
167
168 for (i = 0; i < 5; i++) {
169 key = 0;
170 while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
171 bpf_map_lookup_elem(map_fd[0], &next_key, &value);
172 printf("location 0x%lx count %ld\n", next_key, value);
173 key = next_key;
174 }
175 if (key)
176 printf("\n");
177 sleep(1);
178 }
179 print_hist(map_fd[1]);
180
181 cleanup:
182 for (j--; j >= 0; j--)
183 bpf_link__destroy(links[j]);
184
185 bpf_object__close(obj);
186 return 0;
187 }
188