cregit-Linux how code gets into the kernel

Release 4.9 samples/bpf/tracex2_user.c

Directory: samples/bpf
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <linux/bpf.h>
#include <string.h>
#include "libbpf.h"
#include "bpf_load.h"


#define MAX_INDEX	64

#define MAX_STARS	38


static void stars(char *str, long val, long max, int width) { int i; for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++) str[i] = '*'; if (val > max) str[i - 1] = '+'; str[i] = '\0'; }

Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov78100.00%1100.00%
Total78100.00%1100.00%

struct task { char comm[16]; __u64 pid_tgid; __u64 uid_gid; }; struct hist_key { struct task t; __u32 index; }; #define SIZE sizeof(struct task)
static void print_hist_for_pid(int fd, void *task) { struct hist_key key = {}, next_key; unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); long values[nr_cpus]; char starstr[MAX_STARS]; long value; long data[MAX_INDEX] = {}; int max_ind = -1; long max_value = 0; int i, ind; while (bpf_get_next_key(fd, &key, &next_key) == 0) { if (memcmp(&next_key, task, SIZE)) { key = next_key; continue; } bpf_lookup_elem(fd, &next_key, values); value = 0; for (i = 0; i < nr_cpus; i++) value += values[i]; ind = next_key.index; data[ind] = value; if (value && ind > max_ind) max_ind = ind; if (value > max_value) max_value = value; key = next_key; } printf(" syscall write() stats\n"); printf(" byte_size : count distribution\n"); for (i = 1; i <= max_ind + 1; i++) { stars(starstr, data[i - 1], max_value, MAX_STARS); printf("%8ld -> %-8ld : %-8ld |%-*s|\n", (1l << i) >> 1, (1l << i) - 1, data[i - 1], MAX_STARS, starstr); } }

Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov253100.00%3100.00%
Total253100.00%3100.00%


static void print_hist(int fd) { struct hist_key key = {}, next_key; static struct task tasks[1024]; int task_cnt = 0; int i; while (bpf_get_next_key(fd, &key, &next_key) == 0) { int found = 0; for (i = 0; i < task_cnt; i++) if (memcmp(&tasks[i], &next_key, SIZE) == 0) found = 1; if (!found) memcpy(&tasks[task_cnt++], &next_key, SIZE); key = next_key; } for (i = 0; i < task_cnt; i++) { printf("\npid %d cmd %s uid %d\n", (__u32) tasks[i].pid_tgid, tasks[i].comm, (__u32) tasks[i].uid_gid); print_hist_for_pid(fd, &tasks[i]); } }

Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov172100.00%1100.00%
Total172100.00%1100.00%


static void int_exit(int sig) { print_hist(map_fd[1]); exit(0); }

Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov22100.00%1100.00%
Total22100.00%1100.00%


int main(int ac, char **argv) { char filename[256]; long key, next_key, value; FILE *f; int i; snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); signal(SIGINT, int_exit); /* start 'ping' in the background to have some kfree_skb events */ f = popen("ping -c5 localhost", "r"); (void) f; /* start 'dd' in the background to have plenty of 'write' syscalls */ f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r"); (void) f; if (load_bpf_file(filename)) { printf("%s", bpf_log_buf); return 1; } for (i = 0; i < 5; i++) { key = 0; while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) { bpf_lookup_elem(map_fd[0], &next_key, &value); printf("location 0x%lx count %ld\n", next_key, value); key = next_key; } if (key) printf("\n"); sleep(1); } print_hist(map_fd[1]); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov197100.00%1100.00%
Total197100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov787100.00%3100.00%
Total787100.00%3100.00%
Directory: samples/bpf