tc/tc_exec.c

   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;
  23
  24 static void usage(void)
  25 {
  26         fprintf(stderr,
  27                 "Usage: tc exec [ EXEC_TYPE ] [ help | OPTIONS ]\n"
  28                 "Where:\n"
  29                 "EXEC_TYPE := { bpf | etc. }\n"
  30                 "OPTIONS := ... try tc exec <desired EXEC_KIND> help\n");
  31 }
  32
  33 static int parse_noeopt(struct exec_util *eu, int argc, char **argv)
  34 {
  35         if (argc) {
  36                 fprintf(stderr, "Unknown exec \"%s\", hence option \"%s\" is unparsable\n",
  37                         eu->id, *argv);
  38                 return -1;
  39         }
  40
  41         return 0;
  42 }
  43
  44 static struct exec_util *get_exec_kind(const char *name)
  45 {
  46         struct exec_util *eu;
  47         char buf[256];
  48         void *dlh;
  49
  50         for (eu = exec_list; eu; eu = eu->next)
  51                 if (strcmp(eu->id, name) == 0)
  52                         return eu;
  53
  54         snprintf(buf, sizeof(buf), "%s/e_%s.so", get_tc_lib(), name);
  55         dlh = dlopen(buf, RTLD_LAZY);
  56         if (dlh == NULL) {
  57                 dlh = BODY;
  58                 if (dlh == NULL) {
  59                         dlh = BODY = dlopen(NULL, RTLD_LAZY);
  60                         if (dlh == NULL)
  61                                 goto noexist;
  62                 }
  63         }
  64
  65         snprintf(buf, sizeof(buf), "%s_exec_util", name);
  66         eu = dlsym(dlh, buf);
  67         if (eu == NULL)
  68                 goto noexist;
  69 reg:
  70         eu->next = exec_list;
  71         exec_list = eu;
  72
  73         return eu;
  74 noexist:
  75         eu = calloc(1, sizeof(*eu));
  76         if (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
  85 int do_exec(int argc, char **argv)
  86 {
  87         struct exec_util *eu;
  88         char kind[FILTER_NAMESZ] = {};
  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         strncpy(kind, *argv, sizeof(kind) - 1);
 101
 102         eu = get_exec_kind(kind);
 103
 104         argc--;
 105         argv++;
 106
 107         return eu->parse_eopt(eu, argc, argv);
 108 }