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
21 static struct exec_util *exec_list;
22 static void *BODY = NULL;
23
usage(void)24 static 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
parse_noeopt(struct exec_util * eu,int argc,char ** argv)32 static 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
get_exec_kind(const char * name)43 static 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;
68 reg:
69 eu->next = exec_list;
70 exec_list = eu;
71
72 return eu;
73 noexist:
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
do_exec(int argc,char ** argv)85 int 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