lib/module.c

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  20  * DEALINGS IN THE SOFTWARE.
  21  */
  22
  23 #include "config.h"
  24
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <limits.h>
  30 #include <dlfcn.h>
  31
  32 #include "module.h"
  33 #include "memory.h"
  34 #include "version.h"
  35
  36 DEFINE_MTYPE_STATIC(LIB, MODULE_LOADNAME, "Module loading name")
  37 DEFINE_MTYPE_STATIC(LIB, MODULE_LOADARGS, "Module loading arguments")
  38
  39 static struct frrmod_info frrmod_default_info = {
  40         .name = "libfrr",
  41         .version = FRR_VERSION,
  42         .description = "libfrr core module",
  43 };
  44 union _frrmod_runtime_u frrmod_default = {
  45         .r.info = &frrmod_default_info,
  46         .r.finished_loading = 1,
  47 };
  48
  49 // if defined(HAVE_SYS_WEAK_ALIAS_ATTRIBUTE)
  50 // union _frrmod_runtime_u _frrmod_this_module
  51 //      __attribute__((weak, alias("frrmod_default")));
  52 // elif defined(HAVE_SYS_WEAK_ALIAS_PRAGMA)
  53 #pragma weak _frrmod_this_module = frrmod_default
  54 // else
  55 // error need weak symbol support
  56 // endif
  57
  58 struct frrmod_runtime *frrmod_list = &frrmod_default.r;
  59 static struct frrmod_runtime **frrmod_last = &frrmod_default.r.next;
  60 static const char *execname = NULL;
  61
  62 void frrmod_init(struct frrmod_runtime *modinfo)
  63 {
  64         modinfo->finished_loading = 1;
  65         *frrmod_last = modinfo;
  66         frrmod_last = &modinfo->next;
  67
  68         execname = modinfo->info->name;
  69 }
  70
  71 struct frrmod_runtime *frrmod_load(const char *spec, const char *dir, char *err,
  72                                    size_t err_len)
  73 {
  74         void *handle = NULL;
  75         char name[PATH_MAX], fullpath[PATH_MAX], *args;
  76         struct frrmod_runtime *rtinfo, **rtinfop;
  77         const struct frrmod_info *info;
  78
  79         snprintf(name, sizeof(name), "%s", spec);
  80         args = strchr(name, ':');
  81         if (args)
  82                 *args++ = '\0';
  83
  84         if (!strchr(name, '/')) {
  85                 if (!handle && execname) {
  86                         snprintf(fullpath, sizeof(fullpath), "%s/%s_%s.so", dir,
  87                                  execname, name);
  88                         handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  89                 }
  90                 if (!handle) {
  91                         snprintf(fullpath, sizeof(fullpath), "%s/%s.so", dir,
  92                                  name);
  93                         handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  94                 }
  95         }
  96         if (!handle) {
  97                 snprintf(fullpath, sizeof(fullpath), "%s", name);
  98                 handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  99         }
 100         if (!handle) {
 101                 if (err)
 102                         snprintf(err, err_len,
 103                                  "loading module \"%s\" failed: %s", name,
 104                                  dlerror());
 105                 return NULL;
 106         }
 107
 108         rtinfop = dlsym(handle, "frr_module");
 109         if (!rtinfop) {
 110                 dlclose(handle);
 111                 if (err)
 112                         snprintf(err, err_len,
 113                                  "\"%s\" is not an FRR module: %s", name,
 114                                  dlerror());
 115                 return NULL;
 116         }
 117         rtinfo = *rtinfop;
 118         rtinfo->load_name = XSTRDUP(MTYPE_MODULE_LOADNAME, name);
 119         rtinfo->dl_handle = handle;
 120         if (args)
 121                 rtinfo->load_args = XSTRDUP(MTYPE_MODULE_LOADARGS, args);
 122         info = rtinfo->info;
 123
 124         if (rtinfo->finished_loading) {
 125                 dlclose(handle);
 126                 if (err)
 127                         snprintf(err, err_len, "module \"%s\" already loaded",
 128                                  name);
 129                 goto out_fail;
 130         }
 131
 132         if (info->init && info->init()) {
 133                 dlclose(handle);
 134                 if (err)
 135                         snprintf(err, err_len,
 136                                  "module \"%s\" initialisation failed", name);
 137                 goto out_fail;
 138         }
 139
 140         rtinfo->finished_loading = 1;
 141
 142         *frrmod_last = rtinfo;
 143         frrmod_last = &rtinfo->next;
 144         return rtinfo;
 145
 146 out_fail:
 147         if (rtinfo->load_args)
 148                 XFREE(MTYPE_MODULE_LOADARGS, rtinfo->load_args);
 149         XFREE(MTYPE_MODULE_LOADNAME, rtinfo->load_name);
 150         return NULL;
 151 }
 152
 153 #if 0
 154 void frrmod_unload(struct frrmod_runtime *module)
 155 {
 156 }
 157 #endif