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 =
  46                 {
  47                         .info = &frrmod_default_info,
  48                         .finished_loading = 1,
  49                 },
  50 };
  51
  52 // if defined(HAVE_SYS_WEAK_ALIAS_ATTRIBUTE)
  53 // union _frrmod_runtime_u _frrmod_this_module
  54 //      __attribute__((weak, alias("frrmod_default")));
  55 // elif defined(HAVE_SYS_WEAK_ALIAS_PRAGMA)
  56 #pragma weak _frrmod_this_module = frrmod_default
  57 // else
  58 // error need weak symbol support
  59 // endif
  60
  61 struct frrmod_runtime *frrmod_list = &frrmod_default.r;
  62 static struct frrmod_runtime **frrmod_last = &frrmod_default.r.next;
  63 static const char *execname = NULL;
  64
  65 void frrmod_init(struct frrmod_runtime *modinfo)
  66 {
  67         modinfo->finished_loading = 1;
  68         *frrmod_last = modinfo;
  69         frrmod_last = &modinfo->next;
  70
  71         execname = modinfo->info->name;
  72 }
  73
  74 struct frrmod_runtime *frrmod_load(const char *spec, const char *dir, char *err,
  75                                    size_t err_len)
  76 {
  77         void *handle = NULL;
  78         char name[PATH_MAX], fullpath[PATH_MAX * 2], *args;
  79         struct frrmod_runtime *rtinfo, **rtinfop;
  80         const struct frrmod_info *info;
  81
  82         snprintf(name, sizeof(name), "%s", spec);
  83         args = strchr(name, ':');
  84         if (args)
  85                 *args++ = '\0';
  86
  87         if (!strchr(name, '/')) {
  88                 if (execname) {
  89                         snprintf(fullpath, sizeof(fullpath), "%s/%s_%s.so", dir,
  90                                  execname, name);
  91                         handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  92                 }
  93                 if (!handle) {
  94                         snprintf(fullpath, sizeof(fullpath), "%s/%s.so", dir,
  95                                  name);
  96                         handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
  97                 }
  98         }
  99         if (!handle) {
 100                 snprintf(fullpath, sizeof(fullpath), "%s", name);
 101                 handle = dlopen(fullpath, RTLD_NOW | RTLD_GLOBAL);
 102         }
 103         if (!handle) {
 104                 if (err)
 105                         snprintf(err, err_len,
 106                                  "loading module \"%s\" failed: %s", name,
 107                                  dlerror());
 108                 return NULL;
 109         }
 110
 111         rtinfop = dlsym(handle, "frr_module");
 112         if (!rtinfop) {
 113                 dlclose(handle);
 114                 if (err)
 115                         snprintf(err, err_len,
 116                                  "\"%s\" is not an FRR module: %s", name,
 117                                  dlerror());
 118                 return NULL;
 119         }
 120         rtinfo = *rtinfop;
 121         rtinfo->load_name = XSTRDUP(MTYPE_MODULE_LOADNAME, name);
 122         rtinfo->dl_handle = handle;
 123         if (args)
 124                 rtinfo->load_args = XSTRDUP(MTYPE_MODULE_LOADARGS, args);
 125         info = rtinfo->info;
 126
 127         if (rtinfo->finished_loading) {
 128                 dlclose(handle);
 129                 if (err)
 130                         snprintf(err, err_len, "module \"%s\" already loaded",
 131                                  name);
 132                 goto out_fail;
 133         }
 134
 135         if (info->init && info->init()) {
 136                 dlclose(handle);
 137                 if (err)
 138                         snprintf(err, err_len,
 139                                  "module \"%s\" initialisation failed", name);
 140                 goto out_fail;
 141         }
 142
 143         rtinfo->finished_loading = 1;
 144
 145         *frrmod_last = rtinfo;
 146         frrmod_last = &rtinfo->next;
 147         return rtinfo;
 148
 149 out_fail:
 150         if (rtinfo->load_args)
 151                 XFREE(MTYPE_MODULE_LOADARGS, rtinfo->load_args);
 152         XFREE(MTYPE_MODULE_LOADNAME, rtinfo->load_name);
 153         return NULL;
 154 }
 155
 156 #if 0
 157 void frrmod_unload(struct frrmod_runtime *module)
 158 {
 159 }
 160 #endif