1/*
2 * tc_exec.c	"tc exec".
3 *
4 *		This program is free software; you can redistribute it and/or
5 *		modify it under the terms of the GNU General Public License
6 *		as published by the Free Software Foundation; either version
7 *		2 of the License, or (at your option) any later version.
8 *
9 * Authors:	Daniel Borkmann <daniel@iogearbox.net>
10 */
11
12#include <stdio.h>
13#include <stdlib.h>
14#include <dlfcn.h>
15
16#include "utils.h"
17
18#include "tc_util.h"
19#include "tc_common.h"
20
21static struct exec_util *exec_list;
22static void *BODY = NULL;
23
24static void usage(void)
25{
26	fprintf(stderr, "Usage: tc exec [ EXEC_TYPE ] [ help | OPTIONS ]\n");
27	fprintf(stderr, "Where:\n");
28	fprintf(stderr, "EXEC_TYPE := { bpf | etc. }\n");
29	fprintf(stderr, "OPTIONS := ... try tc exec <desired EXEC_KIND> help\n");
30}
31
32static int parse_noeopt(struct exec_util *eu, int argc, char **argv)
33{
34	if (argc) {
35		fprintf(stderr, "Unknown exec \"%s\", hence option \"%s\" "
36			"is unparsable\n", eu->id, *argv);
37		return -1;
38	}
39
40	return 0;
41}
42
43static struct exec_util *get_exec_kind(const char *name)
44{
45	struct exec_util *eu;
46	char buf[256];
47	void *dlh;
48
49	for (eu = exec_list; eu; eu = eu->next)
50		if (strcmp(eu->id, name) == 0)
51			return eu;
52
53	snprintf(buf, sizeof(buf), "%s/e_%s.so", get_tc_lib(), name);
54	dlh = dlopen(buf, RTLD_LAZY);
55	if (dlh == NULL) {
56		dlh = BODY;
57		if (dlh == NULL) {
58			dlh = BODY = dlopen(NULL, RTLD_LAZY);
59			if (dlh == NULL)
60				goto noexist;
61		}
62	}
63
64	snprintf(buf, sizeof(buf), "%s_exec_util", name);
65	eu = dlsym(dlh, buf);
66	if (eu == NULL)
67		goto noexist;
68reg:
69	eu->next = exec_list;
70	exec_list = eu;
71
72	return eu;
73noexist:
74	eu = malloc(sizeof(*eu));
75	if (eu) {
76		memset(eu, 0, sizeof(*eu));
77		strncpy(eu->id, name, sizeof(eu->id) - 1);
78		eu->parse_eopt = parse_noeopt;
79		goto reg;
80	}
81
82	return eu;
83}
84
85int do_exec(int argc, char **argv)
86{
87	struct exec_util *eu;
88	char kind[16];
89
90	if (argc < 1) {
91		fprintf(stderr, "No command given, try \"tc exec help\".\n");
92		return -1;
93	}
94
95	if (matches(*argv, "help") == 0) {
96		usage();
97		return 0;
98	}
99
100	memset(kind, 0, sizeof(kind));
101	strncpy(kind, *argv, sizeof(kind) - 1);
102
103	eu = get_exec_kind(kind);
104
105	argc--;
106	argv++;
107
108	return eu->parse_eopt(eu, argc, argv);
109}
110