1/* Copyright (c) 2017 Facebook
 2 *
 3 * This program is free software; you can redistribute it and/or
 4 * modify it under the terms of version 2 of the GNU General Public
 5 * License as published by the Free Software Foundation.
 6 */
 7#include <stdio.h>
 8#include <stdlib.h>
 9#include <string.h>
10#include <linux/bpf.h>
11#include "libbpf.h"
12#include "bpf_load.h"
13#include <unistd.h>
14#include <errno.h>
15#include <fcntl.h>
16#include <linux/unistd.h>
17
18static void usage(char *pname)
19{
20	printf("USAGE:\n  %s [-l] <cg-path> <prog filename>\n", pname);
21	printf("\tLoad and attach a sock_ops program to the specified "
22	       "cgroup\n");
23	printf("\tIf \"-l\" is used, the program will continue to run\n");
24	printf("\tprinting the BPF log buffer\n");
25	printf("\tIf the specified filename does not end in \".o\", it\n");
26	printf("\tappends \"_kern.o\" to the name\n");
27	printf("\n");
28	printf("  %s -r <cg-path>\n", pname);
29	printf("\tDetaches the currently attached sock_ops program\n");
30	printf("\tfrom the specified cgroup\n");
31	printf("\n");
32	exit(1);
33}
34
35int main(int argc, char **argv)
36{
37	int logFlag = 0;
38	int error = 0;
39	char *cg_path;
40	char fn[500];
41	char *prog;
42	int cg_fd;
43
44	if (argc < 3)
45		usage(argv[0]);
46
47	if (!strcmp(argv[1], "-r")) {
48		cg_path = argv[2];
49		cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
50		error = bpf_prog_detach(cg_fd, BPF_CGROUP_SOCK_OPS);
51		if (error) {
52			printf("ERROR: bpf_prog_detach: %d (%s)\n",
53			       error, strerror(errno));
54			return 2;
55		}
56		return 0;
57	} else if (!strcmp(argv[1], "-h")) {
58		usage(argv[0]);
59	} else if (!strcmp(argv[1], "-l")) {
60		logFlag = 1;
61		if (argc < 4)
62			usage(argv[0]);
63	}
64
65	prog = argv[argc - 1];
66	cg_path = argv[argc - 2];
67	if (strlen(prog) > 480) {
68		fprintf(stderr, "ERROR: program name too long (> 480 chars)\n");
69		return 3;
70	}
71	cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
72
73	if (!strcmp(prog + strlen(prog)-2, ".o"))
74		strcpy(fn, prog);
75	else
76		sprintf(fn, "%s_kern.o", prog);
77	if (logFlag)
78		printf("loading bpf file:%s\n", fn);
79	if (load_bpf_file(fn)) {
80		printf("ERROR: load_bpf_file failed for: %s\n", fn);
81		printf("%s", bpf_log_buf);
82		return 4;
83	}
84	if (logFlag)
85		printf("TCP BPF Loaded %s\n", fn);
86
87	error = bpf_prog_attach(prog_fd[0], cg_fd, BPF_CGROUP_SOCK_OPS, 0);
88	if (error) {
89		printf("ERROR: bpf_prog_attach: %d (%s)\n",
90		       error, strerror(errno));
91		return 5;
92	} else if (logFlag) {
93		read_trace_pipe();
94	}
95
96	return error;
97}