src/core/plugin.c

   1 /*
   2  * SysDB - src/core/plugin.c
   3  * Copyright (C) 2012 Sebastian 'tokkee' Harl <sh@tokkee.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  17  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #if HAVE_CONFIG_H
  29 #       include "config.h"
  30 #endif /* HAVE_CONFIG_H */
  31
  32 #include "sysdb.h"
  33 #include "core/plugin.h"
  34 #include "core/time.h"
  35 #include "utils/error.h"
  36 #include "utils/llist.h"
  37 #include "utils/strbuf.h"
  38
  39 #include <assert.h>
  40
  41 #include <errno.h>
  42
  43 #include <stdarg.h>
  44 #include <stdio.h>
  45 #include <string.h>
  46 #include <strings.h>
  47 #include <unistd.h>
  48
  49 #include <ltdl.h>
  50
  51 #include <pthread.h>
  52
  53 /* helper to access info attributes */
  54 #define INFO_GET(i, attr) \
  55         ((i)->attr ? (i)->attr : #attr" not set")
  56
  57 /*
  58  * private data types
  59  */
  60
  61 typedef struct {
  62         sdb_object_t super;
  63         sdb_plugin_ctx_t public;
  64
  65         sdb_plugin_info_t info;
  66         lt_dlhandle handle;
  67
  68         /* The usage count differs from the object's ref count
  69          * in that it provides higher level information about how
  70          * the plugin is in use. */
  71         size_t use_cnt;
  72 } ctx_t;
  73 #define CTX_INIT { SDB_OBJECT_INIT, \
  74         SDB_PLUGIN_CTX_INIT, SDB_PLUGIN_INFO_INIT, NULL, 0 }
  75
  76 #define CTX(obj) ((ctx_t *)(obj))
  77
  78 typedef struct {
  79         sdb_object_t super;
  80         void *cb_callback;
  81         sdb_object_t *cb_user_data;
  82         ctx_t *cb_ctx;
  83 } sdb_plugin_cb_t;
  84 #define SDB_PLUGIN_CB_INIT { SDB_OBJECT_INIT, \
  85         /* callback = */ NULL, /* user_data = */ NULL, \
  86         SDB_PLUGIN_CTX_INIT }
  87
  88 typedef struct {
  89         sdb_plugin_cb_t super;
  90 #define ccb_callback super.cb_callback
  91 #define ccb_user_data super.cb_user_data
  92 #define ccb_ctx super.cb_ctx
  93         sdb_time_t ccb_interval;
  94         sdb_time_t ccb_next_update;
  95 } sdb_plugin_collector_cb_t;
  96
  97 #define SDB_PLUGIN_CB(obj) ((sdb_plugin_cb_t *)(obj))
  98 #define SDB_CONST_PLUGIN_CB(obj) ((const sdb_plugin_cb_t *)(obj))
  99 #define SDB_PLUGIN_CCB(obj) ((sdb_plugin_collector_cb_t *)(obj))
 100 #define SDB_CONST_PLUGIN_CCB(obj) ((const sdb_plugin_collector_cb_t *)(obj))
 101
 102 /*
 103  * private variables
 104  */
 105
 106 static sdb_plugin_ctx_t  plugin_default_ctx  = SDB_PLUGIN_CTX_INIT;
 107 static sdb_plugin_info_t plugin_default_info = SDB_PLUGIN_INFO_INIT;
 108
 109 static pthread_key_t     plugin_ctx_key;
 110 static _Bool             plugin_ctx_key_initialized = 0;
 111
 112 /* a list of the plugin contexts of all registered plugins */
 113 static sdb_llist_t      *all_plugins = NULL;
 114
 115 static sdb_llist_t      *config_list = NULL;
 116 static sdb_llist_t      *init_list = NULL;
 117 static sdb_llist_t      *collector_list = NULL;
 118 static sdb_llist_t      *cname_list = NULL;
 119 static sdb_llist_t      *shutdown_list = NULL;
 120 static sdb_llist_t      *log_list = NULL;
 121
 122 static struct {
 123         const char   *type;
 124         sdb_llist_t **list;
 125 } all_lists[] = {
 126         { "config",    &config_list },
 127         { "init",      &init_list },
 128         { "collector", &collector_list },
 129         { "cname",     &cname_list },
 130         { "shutdown",  &shutdown_list },
 131         { "log",       &log_list },
 132 };
 133
 134 /*
 135  * private helper functions
 136  */
 137
 138 static void
 139 plugin_info_clear(sdb_plugin_info_t *info)
 140 {
 141         sdb_plugin_info_t empty_info = SDB_PLUGIN_INFO_INIT;
 142         if (! info)
 143                 return;
 144
 145         if (info->plugin_name)
 146                 free(info->plugin_name);
 147         if (info->filename)
 148                 free(info->filename);
 149
 150         if (info->description)
 151                 free(info->description);
 152         if (info->copyright)
 153                 free(info->copyright);
 154         if (info->license)
 155                 free(info->license);
 156
 157         *info = empty_info;
 158 } /* plugin_info_clear */
 159
 160 static void
 161 ctx_key_init(void)
 162 {
 163         if (plugin_ctx_key_initialized)
 164                 return;
 165
 166         pthread_key_create(&plugin_ctx_key, /* destructor */ NULL);
 167         plugin_ctx_key_initialized = 1;
 168 } /* ctx_key_init */
 169
 170 static int
 171 plugin_cmp_next_update(const sdb_object_t *a, const sdb_object_t *b)
 172 {
 173         const sdb_plugin_collector_cb_t *ccb1
 174                 = (const sdb_plugin_collector_cb_t *)a;
 175         const sdb_plugin_collector_cb_t *ccb2
 176                 = (const sdb_plugin_collector_cb_t *)b;
 177
 178         assert(ccb1 && ccb2);
 179
 180         return (ccb1->ccb_next_update > ccb2->ccb_next_update)
 181                 ? 1 : (ccb1->ccb_next_update < ccb2->ccb_next_update)
 182                 ? -1 : 0;
 183 } /* plugin_cmp_next_update */
 184
 185 static int
 186 plugin_lookup_by_name(const sdb_object_t *obj, const void *id)
 187 {
 188         const sdb_plugin_cb_t *cb = SDB_CONST_PLUGIN_CB(obj);
 189         const char *name = id;
 190
 191         assert(cb && id);
 192
 193         /* when a plugin was registered from outside a plugin (e.g. the core),
 194          * we don't have a plugin context */
 195         if (! cb->cb_ctx)
 196                 return 1;
 197
 198         if (!strcasecmp(cb->cb_ctx->info.plugin_name, name))
 199                 return 0;
 200         return 1;
 201 } /* plugin_lookup_by_name */
 202
 203 /* since this function is called from sdb_plugin_reconfigure_finish()
 204  * when iterating through all_plugins, we may not do any additional
 205  * modifications to all_plugins except for the optional removal */
 206 static void
 207 plugin_unregister_by_name(const char *plugin_name)
 208 {
 209         sdb_object_t *obj;
 210         size_t i;
 211
 212         for (i = 0; i < SDB_STATIC_ARRAY_LEN(all_lists); ++i) {
 213                 const char  *type =  all_lists[i].type;
 214                 sdb_llist_t *list = *all_lists[i].list;
 215
 216                 while (1) {
 217                         sdb_plugin_cb_t *cb;
 218
 219                         cb = SDB_PLUGIN_CB(sdb_llist_remove(list,
 220                                                 plugin_lookup_by_name, plugin_name));
 221                         if (! cb)
 222                                 break;
 223
 224                         assert(cb->cb_ctx);
 225
 226                         sdb_log(SDB_LOG_INFO, "core: Unregistering "
 227                                         "%s callback '%s' (module %s)", type, cb->super.name,
 228                                         cb->cb_ctx->info.plugin_name);
 229                         sdb_object_deref(SDB_OBJ(cb));
 230                 }
 231         }
 232
 233         obj = sdb_llist_search_by_name(all_plugins, plugin_name);
 234         /* when called from sdb_plugin_reconfigure_finish, the object has already
 235          * been removed from the list */
 236         if (obj && (obj->ref_cnt <= 1)) {
 237                 sdb_llist_remove_by_name(all_plugins, plugin_name);
 238                 sdb_object_deref(obj);
 239         }
 240         /* else: other callbacks still reference it */
 241 } /* plugin_unregister_by_name */
 242
 243 static void
 244 plugin_unregister_all(void)
 245 {
 246         size_t i;
 247
 248         for (i = 0; i < SDB_STATIC_ARRAY_LEN(all_lists); ++i) {
 249                 const char  *type =  all_lists[i].type;
 250                 sdb_llist_t *list = *all_lists[i].list;
 251
 252                 size_t len = sdb_llist_len(list);
 253
 254                 if (! len)
 255                         continue;
 256
 257                 sdb_llist_clear(list);
 258                 sdb_log(SDB_LOG_INFO, "core: Unregistered %zu %s callback%s",
 259                                 len, type, len == 1 ? "" : "s");
 260         }
 261 } /* plugin_unregister_all */
 262
 263 /*
 264  * private types
 265  */
 266
 267 static int
 268 ctx_init(sdb_object_t *obj, va_list __attribute__((unused)) ap)
 269 {
 270         ctx_t *ctx = CTX(obj);
 271
 272         assert(ctx);
 273
 274         ctx->public = plugin_default_ctx;
 275         ctx->info = plugin_default_info;
 276         ctx->handle = NULL;
 277         ctx->use_cnt = 1;
 278         return 0;
 279 } /* ctx_init */
 280
 281 static void
 282 ctx_destroy(sdb_object_t *obj)
 283 {
 284         ctx_t *ctx = CTX(obj);
 285
 286         if (ctx->handle) {
 287                 const char *err;
 288
 289                 sdb_log(SDB_LOG_INFO, "core: Unloading module %s",
 290                                 ctx->info.plugin_name);
 291
 292                 lt_dlerror();
 293                 lt_dlclose(ctx->handle);
 294                 if ((err = lt_dlerror()))
 295                         sdb_log(SDB_LOG_WARNING, "core: Failed to unload module %s: %s",
 296                                         ctx->info.plugin_name, err);
 297         }
 298
 299         plugin_info_clear(&ctx->info);
 300 } /* ctx_destroy */
 301
 302 static sdb_type_t ctx_type = {
 303         sizeof(ctx_t),
 304
 305         ctx_init,
 306         ctx_destroy
 307 };
 308
 309 static ctx_t *
 310 ctx_get(void)
 311 {
 312         if (! plugin_ctx_key_initialized)
 313                 ctx_key_init();
 314         return pthread_getspecific(plugin_ctx_key);
 315 } /* ctx_get */
 316
 317 static ctx_t *
 318 ctx_set(ctx_t *new)
 319 {
 320         ctx_t *old;
 321
 322         if (! plugin_ctx_key_initialized)
 323                 ctx_key_init();
 324
 325         old = pthread_getspecific(plugin_ctx_key);
 326         if (old)
 327                 sdb_object_deref(SDB_OBJ(old));
 328         if (new)
 329                 sdb_object_ref(SDB_OBJ(new));
 330         pthread_setspecific(plugin_ctx_key, new);
 331         return old;
 332 } /* ctx_set */
 333
 334 static ctx_t *
 335 ctx_create(const char *name)
 336 {
 337         ctx_t *ctx;
 338
 339         ctx = CTX(sdb_object_create(name, ctx_type));
 340         if (! ctx)
 341                 return NULL;
 342
 343         if (! plugin_ctx_key_initialized)
 344                 ctx_key_init();
 345         ctx_set(ctx);
 346         return ctx;
 347 } /* ctx_create */
 348
 349 static int
 350 plugin_cb_init(sdb_object_t *obj, va_list ap)
 351 {
 352         sdb_llist_t **list = va_arg(ap, sdb_llist_t **);
 353         const char   *type = va_arg(ap, const char *);
 354         void     *callback = va_arg(ap, void *);
 355         sdb_object_t   *ud = va_arg(ap, sdb_object_t *);
 356
 357         assert(list);
 358         assert(type);
 359         assert(obj);
 360
 361         if (sdb_llist_search_by_name(*list, obj->name)) {
 362                 sdb_log(SDB_LOG_WARNING, "core: %s callback '%s' "
 363                                 "has already been registered. Ignoring newly "
 364                                 "registered version.", type, obj->name);
 365                 return -1;
 366         }
 367
 368         /* cb_ctx may be NULL if the plugin was not registered by a plugin */
 369
 370         SDB_PLUGIN_CB(obj)->cb_callback = callback;
 371         SDB_PLUGIN_CB(obj)->cb_ctx      = ctx_get();
 372         sdb_object_ref(SDB_OBJ(SDB_PLUGIN_CB(obj)->cb_ctx));
 373
 374         sdb_object_ref(ud);
 375         SDB_PLUGIN_CB(obj)->cb_user_data = ud;
 376         return 0;
 377 } /* plugin_cb_init */
 378
 379 static void
 380 plugin_cb_destroy(sdb_object_t *obj)
 381 {
 382         assert(obj);
 383         sdb_object_deref(SDB_PLUGIN_CB(obj)->cb_user_data);
 384         sdb_object_deref(SDB_OBJ(SDB_PLUGIN_CB(obj)->cb_ctx));
 385 } /* plugin_cb_destroy */
 386
 387 static sdb_type_t sdb_plugin_cb_type = {
 388         sizeof(sdb_plugin_cb_t),
 389
 390         plugin_cb_init,
 391         plugin_cb_destroy
 392 };
 393
 394 static sdb_type_t sdb_plugin_collector_cb_type = {
 395         sizeof(sdb_plugin_collector_cb_t),
 396
 397         plugin_cb_init,
 398         plugin_cb_destroy
 399 };
 400
 401 static int
 402 module_init(const char *name, lt_dlhandle lh, sdb_plugin_info_t *info)
 403 {
 404         int (*mod_init)(sdb_plugin_info_t *);
 405         int status;
 406
 407         mod_init = (int (*)(sdb_plugin_info_t *))lt_dlsym(lh, "sdb_module_init");
 408         if (! mod_init) {
 409                 sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s': "
 410                                 "could not find symbol 'sdb_module_init'", name);
 411                 return -1;
 412         }
 413
 414         status = mod_init(info);
 415         if (status) {
 416                 sdb_log(SDB_LOG_ERR, "core: Failed to initialize "
 417                                 "module '%s'", name);
 418                 plugin_unregister_by_name(name);
 419                 return -1;
 420         }
 421         return 0;
 422 } /* module_init */
 423
 424 static int
 425 module_load(const char *basedir, const char *name,
 426                 const sdb_plugin_ctx_t *plugin_ctx)
 427 {
 428         char  base_name[name ? strlen(name) + 1 : 1];
 429         const char *name_ptr;
 430         char *tmp;
 431
 432         char filename[1024];
 433         lt_dlhandle lh;
 434
 435         ctx_t *ctx;
 436
 437         int status;
 438
 439         assert(name);
 440
 441         base_name[0] = '\0';
 442         name_ptr = name;
 443
 444         while ((tmp = strstr(name_ptr, "::"))) {
 445                 strncat(base_name, name_ptr, (size_t)(tmp - name_ptr));
 446                 strcat(base_name, "/");
 447                 name_ptr = tmp + strlen("::");
 448         }
 449         strcat(base_name, name_ptr);
 450
 451         if (! basedir)
 452                 basedir = PKGLIBDIR;
 453
 454         snprintf(filename, sizeof(filename), "%s/%s.so", basedir, base_name);
 455         filename[sizeof(filename) - 1] = '\0';
 456
 457         if (access(filename, R_OK)) {
 458                 char errbuf[1024];
 459                 sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s' (%s): %s",
 460                                 name, filename, sdb_strerror(errno, errbuf, sizeof(errbuf)));
 461                 return -1;
 462         }
 463
 464         lt_dlinit();
 465         lt_dlerror();
 466
 467         lh = lt_dlopen(filename);
 468         if (! lh) {
 469                 sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s': %s"
 470                                 "The most common cause for this problem are missing "
 471                                 "dependencies.\n", name, lt_dlerror());
 472                 return -1;
 473         }
 474
 475         if (ctx_get())
 476                 sdb_log(SDB_LOG_WARNING, "core: Discarding old plugin context");
 477
 478         ctx = ctx_create(name);
 479         if (! ctx) {
 480                 sdb_log(SDB_LOG_ERR, "core: Failed to initialize plugin context");
 481                 return -1;
 482         }
 483
 484         ctx->info.plugin_name = strdup(name);
 485         ctx->info.filename = strdup(filename);
 486         ctx->handle = lh;
 487
 488         if (plugin_ctx)
 489                 ctx->public = *plugin_ctx;
 490
 491         if ((status = module_init(name, lh, &ctx->info))) {
 492                 sdb_object_deref(SDB_OBJ(ctx));
 493                 return status;
 494         }
 495
 496         /* compare minor version */
 497         if ((ctx->info.version < 0)
 498                         || ((int)(ctx->info.version / 100) != (int)(SDB_VERSION / 100)))
 499                 sdb_log(SDB_LOG_WARNING, "core: WARNING: version of "
 500                                 "plugin '%s' (%i.%i.%i) does not match our version "
 501                                 "(%i.%i.%i); this might cause problems",
 502                                 name, SDB_VERSION_DECODE(ctx->info.version),
 503                                 SDB_VERSION_DECODE(SDB_VERSION));
 504
 505         sdb_llist_append(all_plugins, SDB_OBJ(ctx));
 506
 507         sdb_log(SDB_LOG_INFO, "core: Successfully loaded "
 508                         "plugin %s v%i (%s)", ctx->info.plugin_name,
 509                         ctx->info.plugin_version,
 510                         INFO_GET(&ctx->info, description));
 511         sdb_log(SDB_LOG_INFO, "core: Plugin %s: %s, License: %s",
 512                         ctx->info.plugin_name,
 513                         INFO_GET(&ctx->info, copyright),
 514                         INFO_GET(&ctx->info, license));
 515
 516         /* any registered callbacks took ownership of the context */
 517         sdb_object_deref(SDB_OBJ(ctx));
 518
 519         /* reset */
 520         ctx_set(NULL);
 521         return 0;
 522 } /* module_load */
 523
 524 static char *
 525 plugin_get_name(const char *name, char *buf, size_t bufsize)
 526 {
 527         ctx_t *ctx = ctx_get();
 528
 529         if (ctx)
 530                 snprintf(buf, bufsize, "%s::%s", ctx->info.plugin_name, name);
 531         else
 532                 snprintf(buf, bufsize, "core::%s", name);
 533         return buf;
 534 } /* plugin_get_name */
 535
 536 static int
 537 plugin_add_callback(sdb_llist_t **list, const char *type,
 538                 const char *name, void *callback, sdb_object_t *user_data)
 539 {
 540         sdb_object_t *obj;
 541
 542         if ((! name) || (! callback))
 543                 return -1;
 544
 545         assert(list);
 546
 547         if (! *list)
 548                 *list = sdb_llist_create();
 549         if (! *list)
 550                 return -1;
 551
 552         obj = sdb_object_create(name, sdb_plugin_cb_type,
 553                         list, type, callback, user_data);
 554         if (! obj)
 555                 return -1;
 556
 557         if (sdb_llist_append(*list, obj)) {
 558                 sdb_object_deref(obj);
 559                 return -1;
 560         }
 561
 562         /* pass control to the list */
 563         sdb_object_deref(obj);
 564
 565         sdb_log(SDB_LOG_INFO, "core: Registered %s callback '%s'.",
 566                         type, name);
 567         return 0;
 568 } /* plugin_add_callback */
 569
 570 /*
 571  * public API
 572  */
 573
 574 int
 575 sdb_plugin_load(const char *basedir, const char *name,
 576                 const sdb_plugin_ctx_t *plugin_ctx)
 577 {
 578         ctx_t *ctx;
 579
 580         int status;
 581
 582         if ((! name) || (! *name))
 583                 return -1;
 584
 585         if (! all_plugins) {
 586                 if (! (all_plugins = sdb_llist_create())) {
 587                         sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s': "
 588                                         "internal error while creating linked list", name);
 589                         return -1;
 590                 }
 591         }
 592
 593         ctx = CTX(sdb_llist_search_by_name(all_plugins, name));
 594         if (ctx) {
 595                 /* plugin already loaded */
 596                 if (! ctx->use_cnt) {
 597                         /* reloading plugin */
 598                         ctx_t *old_ctx = ctx_set(ctx);
 599
 600                         status = module_init(ctx->info.plugin_name, ctx->handle, NULL);
 601                         if (status)
 602                                 return status;
 603
 604                         sdb_log(SDB_LOG_INFO, "core: Successfully reloaded plugin "
 605                                         "'%s' (%s)", ctx->info.plugin_name,
 606                                         INFO_GET(&ctx->info, description));
 607                         ctx_set(old_ctx);
 608                 }
 609                 ++ctx->use_cnt;
 610                 return 0;
 611         }
 612
 613         return module_load(basedir, name, plugin_ctx);
 614 } /* sdb_plugin_load */
 615
 616 int
 617 sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...)
 618 {
 619         va_list ap;
 620
 621         if (! info)
 622                 return -1;
 623
 624         va_start(ap, type);
 625
 626         switch (type) {
 627                 case SDB_PLUGIN_INFO_DESC:
 628                         {
 629                                 char *desc = va_arg(ap, char *);
 630                                 if (desc) {
 631                                         if (info->description)
 632                                                 free(info->description);
 633                                         info->description = strdup(desc);
 634                                 }
 635                         }
 636                         break;
 637                 case SDB_PLUGIN_INFO_COPYRIGHT:
 638                         {
 639                                 char *copyright = va_arg(ap, char *);
 640                                 if (copyright)
 641                                         info->copyright = strdup(copyright);
 642                         }
 643                         break;
 644                 case SDB_PLUGIN_INFO_LICENSE:
 645                         {
 646                                 char *license = va_arg(ap, char *);
 647                                 if (license) {
 648                                         if (info->license)
 649                                                 free(info->license);
 650                                         info->license = strdup(license);
 651                                 }
 652                         }
 653                         break;
 654                 case SDB_PLUGIN_INFO_VERSION:
 655                         {
 656                                 int version = va_arg(ap, int);
 657                                 info->version = version;
 658                         }
 659                         break;
 660                 case SDB_PLUGIN_INFO_PLUGIN_VERSION:
 661                         {
 662                                 int version = va_arg(ap, int);
 663                                 info->plugin_version = version;
 664                         }
 665                         break;
 666                 default:
 667                         va_end(ap);
 668                         return -1;
 669         }
 670
 671         va_end(ap);
 672         return 0;
 673 } /* sdb_plugin_set_info */
 674
 675 int
 676 sdb_plugin_register_config(sdb_plugin_config_cb callback)
 677 {
 678         ctx_t *ctx = ctx_get();
 679
 680         if (! ctx) {
 681                 sdb_log(SDB_LOG_ERR, "core: Invalid attempt to register a "
 682                                 "config callback from outside a plugin");
 683                 return -1;
 684         }
 685         return plugin_add_callback(&config_list, "init", ctx->info.plugin_name,
 686                         (void *)callback, NULL);
 687 } /* sdb_plugin_register_config */
 688
 689 int
 690 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
 691                 sdb_object_t *user_data)
 692 {
 693         char cb_name[1024];
 694         return plugin_add_callback(&init_list, "init",
 695                         plugin_get_name(name, cb_name, sizeof(cb_name)),
 696                         (void *)callback, user_data);
 697 } /* sdb_plugin_register_init */
 698
 699 int
 700 sdb_plugin_register_shutdown(const char *name, sdb_plugin_shutdown_cb callback,
 701                 sdb_object_t *user_data)
 702 {
 703         char cb_name[1024];
 704         return plugin_add_callback(&shutdown_list, "shutdown",
 705                         plugin_get_name(name, cb_name, sizeof(cb_name)),
 706                         (void *)callback, user_data);
 707 } /* sdb_plugin_register_shutdown */
 708
 709 int
 710 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
 711                 sdb_object_t *user_data)
 712 {
 713         char cb_name[1024];
 714         return plugin_add_callback(&log_list, "log",
 715                         plugin_get_name(name, cb_name, sizeof(cb_name)),
 716                         callback, user_data);
 717 } /* sdb_plugin_register_log */
 718
 719 int
 720 sdb_plugin_register_cname(const char *name, sdb_plugin_cname_cb callback,
 721                 sdb_object_t *user_data)
 722 {
 723         char cb_name[1024];
 724         return plugin_add_callback(&cname_list, "cname",
 725                         plugin_get_name(name, cb_name, sizeof(cb_name)),
 726                         callback, user_data);
 727 } /* sdb_plugin_register_cname */
 728
 729 int
 730 sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback,
 731                 const sdb_time_t *interval, sdb_object_t *user_data)
 732 {
 733         char cb_name[1024];
 734         sdb_object_t *obj;
 735
 736         if ((! name) || (! callback))
 737                 return -1;
 738
 739         if (! collector_list)
 740                 collector_list = sdb_llist_create();
 741         if (! collector_list)
 742                 return -1;
 743
 744         plugin_get_name(name, cb_name, sizeof(cb_name));
 745
 746         obj = sdb_object_create(cb_name, sdb_plugin_collector_cb_type,
 747                         &collector_list, "collector", callback, user_data);
 748         if (! obj)
 749                 return -1;
 750
 751         if (interval)
 752                 SDB_PLUGIN_CCB(obj)->ccb_interval = *interval;
 753         else {
 754                 sdb_time_t tmp = sdb_plugin_get_ctx().interval;
 755
 756                 if (tmp > 0)
 757                         SDB_PLUGIN_CCB(obj)->ccb_interval = tmp;
 758                 else
 759                         SDB_PLUGIN_CCB(obj)->ccb_interval = 0;
 760         }
 761
 762         if (! (SDB_PLUGIN_CCB(obj)->ccb_next_update = sdb_gettime())) {
 763                 char errbuf[1024];
 764                 sdb_log(SDB_LOG_ERR, "core: Failed to determine current "
 765                                 "time: %s", sdb_strerror(errno, errbuf, sizeof(errbuf)));
 766                 sdb_object_deref(obj);
 767                 return -1;
 768         }
 769
 770         if (sdb_llist_insert_sorted(collector_list, obj,
 771                                 plugin_cmp_next_update)) {
 772                 sdb_object_deref(obj);
 773                 return -1;
 774         }
 775
 776         /* pass control to the list */
 777         sdb_object_deref(obj);
 778
 779         sdb_log(SDB_LOG_INFO, "core: Registered collector callback '%s' "
 780                         "(interval = %.3fs).", cb_name,
 781                         SDB_TIME_TO_DOUBLE(SDB_PLUGIN_CCB(obj)->ccb_interval));
 782         return 0;
 783 } /* sdb_plugin_register_collector */
 784
 785 sdb_plugin_ctx_t
 786 sdb_plugin_get_ctx(void)
 787 {
 788         ctx_t *c;
 789
 790         c = ctx_get();
 791         if (! c) {
 792                 sdb_plugin_log(SDB_LOG_ERR, "core: Invalid read access to plugin "
 793                                 "context outside a plugin");
 794                 return plugin_default_ctx;
 795         }
 796         return c->public;
 797 } /* sdb_plugin_get_ctx */
 798
 799 int
 800 sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx, sdb_plugin_ctx_t *old)
 801 {
 802         ctx_t *c;
 803
 804         c = ctx_get();
 805         if (! c) {
 806                 sdb_plugin_log(SDB_LOG_ERR, "core: Invalid write access to plugin "
 807                                 "context outside a plugin");
 808                 return -1;
 809         }
 810
 811         if (old)
 812                 *old = c->public;
 813         c->public = ctx;
 814         return 0;
 815 } /* sdb_plugin_set_ctx */
 816
 817 int
 818 sdb_plugin_configure(const char *name, oconfig_item_t *ci)
 819 {
 820         sdb_plugin_cb_t *plugin;
 821         sdb_plugin_config_cb callback;
 822
 823         ctx_t *old_ctx;
 824
 825         int status;
 826
 827         if ((! name) || (! ci))
 828                 return -1;
 829
 830         plugin = SDB_PLUGIN_CB(sdb_llist_search_by_name(config_list, name));
 831         if (! plugin) {
 832                 ctx_t *ctx = CTX(sdb_llist_search_by_name(all_plugins, name));
 833                 if (! ctx)
 834                         sdb_log(SDB_LOG_ERR, "core: Cannot configure unknown "
 835                                         "plugin '%s'. Missing 'LoadPlugin \"%s\"'?",
 836                                         name, name);
 837                 else
 838                         sdb_log(SDB_LOG_ERR, "core: Plugin '%s' did not register "
 839                                         "a config callback.", name);
 840                 errno = ENOENT;
 841                 return -1;
 842         }
 843
 844         old_ctx = ctx_set(plugin->cb_ctx);
 845         callback = (sdb_plugin_config_cb)plugin->cb_callback;
 846         status = callback(ci);
 847         ctx_set(old_ctx);
 848         return status;
 849 } /* sdb_plugin_configure */
 850
 851 int
 852 sdb_plugin_reconfigure_init(void)
 853 {
 854         sdb_llist_iter_t *iter;
 855
 856         iter = sdb_llist_get_iter(config_list);
 857         if (config_list && (! iter))
 858                 return -1;
 859
 860         /* deconfigure all plugins */
 861         while (sdb_llist_iter_has_next(iter)) {
 862                 sdb_plugin_cb_t *plugin;
 863                 sdb_plugin_config_cb callback;
 864                 ctx_t *old_ctx;
 865
 866                 plugin = SDB_PLUGIN_CB(sdb_llist_iter_get_next(iter));
 867                 old_ctx = ctx_set(plugin->cb_ctx);
 868                 callback = (sdb_plugin_config_cb)plugin->cb_callback;
 869                 callback(NULL);
 870                 ctx_set(old_ctx);
 871         }
 872         sdb_llist_iter_destroy(iter);
 873
 874         iter = sdb_llist_get_iter(all_plugins);
 875         if (all_plugins && (! iter))
 876                 return -1;
 877
 878         /* record all plugins as being unused */
 879         while (sdb_llist_iter_has_next(iter))
 880                 CTX(sdb_llist_iter_get_next(iter))->use_cnt = 0;
 881         sdb_llist_iter_destroy(iter);
 882
 883         plugin_unregister_all();
 884         return 0;
 885 } /* sdb_plugin_reconfigure_init */
 886
 887 int
 888 sdb_plugin_reconfigure_finish(void)
 889 {
 890         sdb_llist_iter_t *iter;
 891
 892         iter = sdb_llist_get_iter(all_plugins);
 893         if (all_plugins && (! iter))
 894                 return -1;
 895
 896         while (sdb_llist_iter_has_next(iter)) {
 897                 ctx_t *ctx = CTX(sdb_llist_iter_get_next(iter));
 898                 if (ctx->use_cnt)
 899                         continue;
 900
 901                 sdb_log(SDB_LOG_INFO, "core: Module %s no longer in use",
 902                                 ctx->info.plugin_name);
 903                 sdb_llist_iter_remove_current(iter);
 904                 plugin_unregister_by_name(ctx->info.plugin_name);
 905                 sdb_object_deref(SDB_OBJ(ctx));
 906         }
 907         sdb_llist_iter_destroy(iter);
 908         return 0;
 909 } /* sdb_plugin_reconfigure_finish */
 910
 911 int
 912 sdb_plugin_init_all(void)
 913 {
 914         sdb_llist_iter_t *iter;
 915         int ret = 0;
 916
 917         iter = sdb_llist_get_iter(init_list);
 918         while (sdb_llist_iter_has_next(iter)) {
 919                 sdb_plugin_cb_t *cb;
 920                 sdb_plugin_init_cb callback;
 921                 ctx_t *old_ctx;
 922
 923                 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 924                 assert(obj);
 925                 cb = SDB_PLUGIN_CB(obj);
 926
 927                 callback = (sdb_plugin_init_cb)cb->cb_callback;
 928
 929                 old_ctx = ctx_set(cb->cb_ctx);
 930                 if (callback(cb->cb_user_data)) {
 931                         sdb_log(SDB_LOG_ERR, "core: Failed to initialize plugin "
 932                                         "'%s'. Unregistering all callbacks.", obj->name);
 933                         ctx_set(old_ctx);
 934                         plugin_unregister_by_name(cb->cb_ctx->info.plugin_name);
 935                         ++ret;
 936                 }
 937                 else
 938                         ctx_set(old_ctx);
 939         }
 940         sdb_llist_iter_destroy(iter);
 941         return ret;
 942 } /* sdb_plugin_init_all */
 943
 944 int
 945 sdb_plugin_shutdown_all(void)
 946 {
 947         sdb_llist_iter_t *iter;
 948         int ret = 0;
 949
 950         iter = sdb_llist_get_iter(shutdown_list);
 951         while (sdb_llist_iter_has_next(iter)) {
 952                 sdb_plugin_cb_t *cb;
 953                 sdb_plugin_shutdown_cb callback;
 954                 ctx_t *old_ctx;
 955
 956                 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 957                 assert(obj);
 958                 cb = SDB_PLUGIN_CB(obj);
 959
 960                 callback = (sdb_plugin_shutdown_cb)cb->cb_callback;
 961
 962                 old_ctx = ctx_set(cb->cb_ctx);
 963                 if (callback(cb->cb_user_data)) {
 964                         sdb_log(SDB_LOG_ERR, "core: Failed to shutdown plugin '%s'.",
 965                                         obj->name);
 966                         ++ret;
 967                 }
 968                 ctx_set(old_ctx);
 969         }
 970         sdb_llist_iter_destroy(iter);
 971         return ret;
 972 } /* sdb_plugin_shutdown_all */
 973
 974 int
 975 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 976 {
 977         if (! collector_list) {
 978                 sdb_log(SDB_LOG_WARNING, "core: No collectors registered. "
 979                                 "Quiting main loop.");
 980                 return -1;
 981         }
 982
 983         if (! loop)
 984                 return -1;
 985
 986         while (loop->do_loop) {
 987                 sdb_plugin_collector_cb callback;
 988                 ctx_t *old_ctx;
 989
 990                 sdb_time_t interval, now;
 991
 992                 sdb_object_t *obj = sdb_llist_shift(collector_list);
 993                 if (! obj)
 994                         return -1;
 995
 996                 callback = (sdb_plugin_collector_cb)SDB_PLUGIN_CCB(obj)->ccb_callback;
 997
 998                 if (! (now = sdb_gettime())) {
 999                         char errbuf[1024];
1000                         sdb_log(SDB_LOG_ERR, "core: Failed to determine current "
1001                                         "time in collector main loop: %s",
1002                                         sdb_strerror(errno, errbuf, sizeof(errbuf)));
1003                         now = SDB_PLUGIN_CCB(obj)->ccb_next_update;
1004                 }
1005
1006                 if (now < SDB_PLUGIN_CCB(obj)->ccb_next_update) {
1007                         interval = SDB_PLUGIN_CCB(obj)->ccb_next_update - now;
1008
1009                         errno = 0;
1010                         while (loop->do_loop && sdb_sleep(interval, &interval)) {
1011                                 if (errno != EINTR) {
1012                                         char errbuf[1024];
1013                                         sdb_log(SDB_LOG_ERR, "core: Failed to sleep "
1014                                                         "in collector main loop: %s",
1015                                                         sdb_strerror(errno, errbuf, sizeof(errbuf)));
1016                                         sdb_llist_insert_sorted(collector_list, obj,
1017                                                         plugin_cmp_next_update);
1018                                         sdb_object_deref(obj);
1019                                         return -1;
1020                                 }
1021                                 errno = 0;
1022                         }
1023
1024                         if (! loop->do_loop) {
1025                                 /* put back; don't worry about errors */
1026                                 sdb_llist_insert_sorted(collector_list, obj,
1027                                                 plugin_cmp_next_update);
1028                                 sdb_object_deref(obj);
1029                                 return 0;
1030                         }
1031                 }
1032
1033                 old_ctx = ctx_set(SDB_PLUGIN_CCB(obj)->ccb_ctx);
1034                 if (callback(SDB_PLUGIN_CCB(obj)->ccb_user_data)) {
1035                         /* XXX */
1036                 }
1037                 ctx_set(old_ctx);
1038
1039                 interval = SDB_PLUGIN_CCB(obj)->ccb_interval;
1040                 if (! interval)
1041                         interval = loop->default_interval;
1042                 if (! interval) {
1043                         sdb_log(SDB_LOG_WARNING, "core: No interval configured "
1044                                         "for plugin '%s'; skipping any further "
1045                                         "iterations.", obj->name);
1046                         sdb_object_deref(obj);
1047                         continue;
1048                 }
1049
1050                 SDB_PLUGIN_CCB(obj)->ccb_next_update += interval;
1051
1052                 if (! (now = sdb_gettime())) {
1053                         char errbuf[1024];
1054                         sdb_log(SDB_LOG_ERR, "core: Failed to determine current "
1055                                         "time in collector main loop: %s",
1056                                         sdb_strerror(errno, errbuf, sizeof(errbuf)));
1057                         now = SDB_PLUGIN_CCB(obj)->ccb_next_update;
1058                 }
1059
1060                 if (now > SDB_PLUGIN_CCB(obj)->ccb_next_update) {
1061                         sdb_log(SDB_LOG_WARNING, "core: Plugin '%s' took too "
1062                                         "long; skipping iterations to keep up.",
1063                                         obj->name);
1064                         SDB_PLUGIN_CCB(obj)->ccb_next_update = now;
1065                 }
1066
1067                 if (sdb_llist_insert_sorted(collector_list, obj,
1068                                         plugin_cmp_next_update)) {
1069                         sdb_log(SDB_LOG_ERR, "core: Failed to re-insert "
1070                                         "plugin '%s' into collector list. Unable to further "
1071                                         "use the plugin.",
1072                                         obj->name);
1073                         sdb_object_deref(obj);
1074                         return -1;
1075                 }
1076
1077                 /* pass control back to the list */
1078                 sdb_object_deref(obj);
1079         }
1080         return 0;
1081 } /* sdb_plugin_read_loop */
1082
1083 char *
1084 sdb_plugin_cname(char *hostname)
1085 {
1086         sdb_llist_iter_t *iter;
1087
1088         if (! hostname)
1089                 return NULL;
1090
1091         if (! cname_list)
1092                 return hostname;
1093
1094         iter = sdb_llist_get_iter(cname_list);
1095         while (sdb_llist_iter_has_next(iter)) {
1096                 sdb_plugin_cname_cb callback;
1097                 char *cname;
1098
1099                 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
1100                 assert(obj);
1101
1102                 callback = (sdb_plugin_cname_cb)SDB_PLUGIN_CB(obj)->cb_callback;
1103                 cname = callback(hostname, SDB_PLUGIN_CB(obj)->cb_user_data);
1104                 if (cname) {
1105                         free(hostname);
1106                         hostname = cname;
1107                 }
1108                 /* else: don't change hostname */
1109         }
1110         sdb_llist_iter_destroy(iter);
1111         return hostname;
1112 } /* sdb_plugin_cname */
1113
1114 int
1115 sdb_plugin_log(int prio, const char *msg)
1116 {
1117         sdb_llist_iter_t *iter;
1118         int ret = -1;
1119
1120         _Bool logged = 0;
1121
1122         if (! msg)
1123                 return 0;
1124
1125         iter = sdb_llist_get_iter(log_list);
1126         while (sdb_llist_iter_has_next(iter)) {
1127                 sdb_plugin_log_cb callback;
1128                 int tmp;
1129
1130                 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
1131                 assert(obj);
1132
1133                 callback = (sdb_plugin_log_cb)SDB_PLUGIN_CB(obj)->cb_callback;
1134                 tmp = callback(prio, msg, SDB_PLUGIN_CB(obj)->cb_user_data);
1135                 if (tmp > ret)
1136                         ret = tmp;
1137
1138                 if (SDB_PLUGIN_CB(obj)->cb_ctx)
1139                         logged = 1;
1140                 /* else: this is an internally registered callback */
1141         }
1142         sdb_llist_iter_destroy(iter);
1143
1144         if (! logged)
1145                 return fprintf(stderr, "[%s] %s\n", SDB_LOG_PRIO_TO_STRING(prio), msg);
1146         return ret;
1147 } /* sdb_plugin_log */
1148
1149 int
1150 sdb_plugin_vlogf(int prio, const char *fmt, va_list ap)
1151 {
1152         sdb_strbuf_t *buf;
1153         int ret;
1154
1155         if (! fmt)
1156                 return 0;
1157
1158         buf = sdb_strbuf_create(64);
1159         if (! buf) {
1160                 ret = fprintf(stderr, "[%s] ", SDB_LOG_PRIO_TO_STRING(prio));
1161                 ret += vfprintf(stderr, fmt, ap);
1162                 return ret;
1163         }
1164
1165         if (sdb_strbuf_vsprintf(buf, fmt, ap) < 0) {
1166                 sdb_strbuf_destroy(buf);
1167                 return -1;
1168         }
1169
1170         ret = sdb_plugin_log(prio, sdb_strbuf_string(buf));
1171         sdb_strbuf_destroy(buf);
1172         return ret;
1173 } /* sdb_plugin_vlogf */
1174
1175 int
1176 sdb_plugin_logf(int prio, const char *fmt, ...)
1177 {
1178         va_list ap;
1179         int ret;
1180
1181         if (! fmt)
1182                 return 0;
1183
1184         va_start(ap, fmt);
1185         ret = sdb_plugin_vlogf(prio, fmt, ap);
1186         va_end(ap);
1187         return ret;
1188 } /* sdb_plugin_logf */
1189
1190 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
1191