lib/module.c

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