src/bin/lttng-sessiond/modprobe.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <dgoulet@efficios.com>
   3  *               2014 - Jan Glauber <jan.glauber@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 /**
  20  * @file modprobe.c
  21  *
  22  * @brief modprobe related functions.
  23  *
  24  */
  25
  26 #define _LGPL_SOURCE
  27 #include <assert.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <sys/wait.h>
  31
  32 #include <common/common.h>
  33 #include <common/utils.h>
  34
  35 #include "modprobe.h"
  36 #include "kern-modules.h"
  37
  38 #define LTTNG_MOD_REQUIRED      1
  39 #define LTTNG_MOD_OPTIONAL      0
  40
  41 /* LTTng kernel tracer mandatory core modules list */
  42 struct kern_modules_param kern_modules_control_core[] = {
  43         { "lttng-ring-buffer-client-discard" },
  44         { "lttng-ring-buffer-client-overwrite" },
  45         { "lttng-ring-buffer-metadata-client" },
  46         { "lttng-ring-buffer-client-mmap-discard" },
  47         { "lttng-ring-buffer-client-mmap-overwrite" },
  48         { "lttng-ring-buffer-metadata-mmap-client" },
  49 };
  50
  51 /* LTTng kernel tracer probe modules list */
  52 struct kern_modules_param kern_modules_probes_default[] = {
  53         { "lttng-probe-asoc" },
  54         { "lttng-probe-block" },
  55         { "lttng-probe-btrfs" },
  56         { "lttng-probe-compaction" },
  57         { "lttng-probe-ext3" },
  58         { "lttng-probe-ext4" },
  59         { "lttng-probe-gpio" },
  60         { "lttng-probe-i2c" },
  61         { "lttng-probe-irq" },
  62         { "lttng-probe-jbd" },
  63         { "lttng-probe-jbd2" },
  64         { "lttng-probe-kmem" },
  65         { "lttng-probe-kvm" },
  66         { "lttng-probe-kvm-x86" },
  67         { "lttng-probe-kvm-x86-mmu" },
  68         { "lttng-probe-lock" },
  69         { "lttng-probe-module" },
  70         { "lttng-probe-napi" },
  71         { "lttng-probe-net" },
  72         { "lttng-probe-power" },
  73         { "lttng-probe-printk" },
  74         { "lttng-probe-random" },
  75         { "lttng-probe-rcu" },
  76         { "lttng-probe-regmap" },
  77         { "lttng-probe-regulator" },
  78         { "lttng-probe-rpm" },
  79         { "lttng-probe-sched" },
  80         { "lttng-probe-scsi" },
  81         { "lttng-probe-signal" },
  82         { "lttng-probe-skb" },
  83         { "lttng-probe-sock" },
  84         { "lttng-probe-statedump" },
  85         { "lttng-probe-sunrpc" },
  86         { "lttng-probe-timer" },
  87         { "lttng-probe-udp" },
  88         { "lttng-probe-vmscan" },
  89         { "lttng-probe-v4l2" },
  90         { "lttng-probe-workqueue" },
  91         { "lttng-probe-writeback" },
  92         { "lttng-probe-x86-irq-vectors" },
  93         { "lttng-probe-x86-exceptions" },
  94 };
  95
  96 /* dynamic probe modules list */
  97 static struct kern_modules_param *probes;
  98 static int nr_probes;
  99 static int probes_capacity;
 100
 101 #if HAVE_KMOD
 102 #include <libkmod.h>
 103
 104 /**
 105  * @brief Logging function for libkmod integration.
 106  */
 107 static void log_kmod(void *data, int priority, const char *file, int line,
 108                 const char *fn, const char *format, va_list args)
 109 {
 110         char *str;
 111
 112         if (vasprintf(&str, format, args) < 0) {
 113                 return;
 114         }
 115
 116         DBG("libkmod: %s", str);
 117         free(str);
 118 }
 119
 120 /**
 121  * @brief Setup the libkmod context.
 122  *
 123  * Create the context, add a custom logging function and preload the
 124  * ressources for faster operation.
 125  *
 126  * @returns     \c 0 on success
 127  *              \c < 0 on error
 128  */
 129 static int setup_kmod_ctx(struct kmod_ctx **ctx)
 130 {
 131         int ret = 0;
 132
 133         *ctx = kmod_new(NULL, NULL);
 134         if (!ctx) {
 135                 PERROR("Unable to create kmod library context");
 136                 ret = -ENOMEM;
 137                 goto error;
 138         }
 139
 140         kmod_set_log_fn(*ctx, log_kmod, NULL);
 141         ret = kmod_load_resources(*ctx);
 142         if (ret < 0) {
 143                 ERR("Failed to load kmod library resources");
 144                 goto error;
 145         }
 146
 147 error:
 148         return ret;
 149 }
 150
 151 /**
 152  * @brief Loads the kernel modules in \p modules
 153  *
 154  * @param modules       List of modules to load
 155  * @param entries       Number of modules in the list
 156  * @param required      Are the modules required or optionnal
 157  *
 158  * If the modules are required, we will return with error after the
 159  * first failed module load, otherwise we continue loading.
 160  *
 161  * @returns             \c 0 on success
 162  *                      \c < 0 on error
 163  */
 164 static int modprobe_lttng(struct kern_modules_param *modules,
 165                 int entries, int required)
 166 {
 167         int ret = 0, i;
 168         struct kmod_ctx *ctx;
 169
 170         ret = setup_kmod_ctx(&ctx);
 171         if (ret < 0) {
 172                 goto error;
 173         }
 174
 175         for (i = 0; i < entries; i++) {
 176                 struct kmod_module *mod = NULL;
 177
 178                 ret = kmod_module_new_from_name(ctx, modules[i].name, &mod);
 179                 if (ret < 0) {
 180                         PERROR("Failed to create kmod module for %s", modules[i].name);
 181                         goto error;
 182                 }
 183
 184                 ret = kmod_module_probe_insert_module(mod, 0,
 185                                 NULL, NULL, NULL, NULL);
 186                 if (ret == -EEXIST) {
 187                         DBG("Module %s is already loaded", modules[i].name);
 188                         ret = 0;
 189                 } else if (ret < 0) {
 190                         if (required) {
 191                                 ERR("Unable to load required module %s",
 192                                                 modules[i].name);
 193                                 goto error;
 194                         } else {
 195                                 DBG("Unable to load optional module %s; continuing",
 196                                                 modules[i].name);
 197                                 ret = 0;
 198                         }
 199                 } else {
 200                         DBG("Modprobe successfully %s", modules[i].name);
 201                         modules[i].loaded = true;
 202                 }
 203
 204                 kmod_module_unref(mod);
 205         }
 206
 207 error:
 208         if (ctx) {
 209                 kmod_unref(ctx);
 210         }
 211         return ret;
 212 }
 213
 214 /**
 215  * @brief Recursively unload modules.
 216  *
 217  * This function implements the same modules unloading behavior as
 218  * 'modprobe -r' or rmmod, it will recursevily go trought the \p module
 219  * dependencies and unload modules with a refcount of 0.
 220  *
 221  * @param mod           The module to unload
 222  *
 223  * @returns             \c 0 on success
 224  *                      \c < 0 on error
 225  */
 226 static int rmmod_recurse(struct kmod_module *mod) {
 227         int ret = 0;
 228         struct kmod_list *deps, *itr;
 229
 230         if (kmod_module_get_initstate(mod) == KMOD_MODULE_BUILTIN) {
 231                 DBG("Module %s is builtin", kmod_module_get_name(mod));
 232                 return ret;
 233         }
 234
 235         ret = kmod_module_remove_module(mod, 0);
 236
 237         deps = kmod_module_get_dependencies(mod);
 238         if (deps != NULL) {
 239                 kmod_list_foreach(itr, deps) {
 240                         struct kmod_module *dep = kmod_module_get_module(itr);
 241                         if (kmod_module_get_refcnt(dep) == 0) {
 242                                 DBG("Recursive remove module %s",
 243                                                 kmod_module_get_name(dep));
 244                                 rmmod_recurse(dep);
 245                         }
 246                         kmod_module_unref(dep);
 247                 }
 248                 kmod_module_unref_list(deps);
 249         }
 250
 251         return ret;
 252 }
 253
 254 /**
 255  * @brief Unloads the kernel modules in \p modules
 256  *
 257  * @param modules       List of modules to unload
 258  * @param entries       Number of modules in the list
 259  * @param required      Are the modules required or optionnal
 260  *
 261  */
 262 static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 263                 int entries, int required)
 264 {
 265         int ret = 0, i;
 266         struct kmod_ctx *ctx;
 267
 268         ret = setup_kmod_ctx(&ctx);
 269         if (ret < 0) {
 270                 goto error;
 271         }
 272
 273         for (i = entries - 1; i >= 0; i--) {
 274                 struct kmod_module *mod = NULL;
 275
 276                 if (!modules[i].loaded) {
 277                         continue;
 278                 }
 279
 280                 ret = kmod_module_new_from_name(ctx, modules[i].name, &mod);
 281                 if (ret < 0) {
 282                         PERROR("Failed to create kmod module for %s", modules[i].name);
 283                         goto error;
 284                 }
 285
 286                 ret = rmmod_recurse(mod);
 287                 if (ret == -EEXIST) {
 288                         DBG("Module %s is not in kernel.", modules[i].name);
 289                 } else if (required && ret < 0) {
 290                         ERR("Unable to remove module %s", modules[i].name);
 291                 } else {
 292                         DBG("Modprobe removal successful %s",
 293                                 modules[i].name);
 294                 }
 295
 296                 kmod_module_unref(mod);
 297         }
 298
 299 error:
 300         if (ctx) {
 301                 kmod_unref(ctx);
 302         }
 303 }
 304
 305 #else /* HAVE_KMOD */
 306
 307 static int modprobe_lttng(struct kern_modules_param *modules,
 308                 int entries, int required)
 309 {
 310         int ret = 0, i;
 311         char modprobe[256];
 312
 313         for (i = 0; i < entries; i++) {
 314                 ret = snprintf(modprobe, sizeof(modprobe),
 315                                 "/sbin/modprobe %s%s",
 316                                 required ? "" : "-q ",
 317                                 modules[i].name);
 318                 if (ret < 0) {
 319                         PERROR("snprintf modprobe");
 320                         goto error;
 321                 }
 322                 modprobe[sizeof(modprobe) - 1] = '\0';
 323                 ret = system(modprobe);
 324                 if (ret == -1) {
 325                         if (required) {
 326                                 ERR("Unable to launch modprobe for required module %s",
 327                                                 modules[i].name);
 328                                 goto error;
 329                         } else {
 330                                 DBG("Unable to launch modprobe for optional module %s; continuing",
 331                                                 modules[i].name);
 332                                 ret = 0;
 333                         }
 334                 } else if (WEXITSTATUS(ret) != 0) {
 335                         if (required) {
 336                                 ERR("Unable to load required module %s",
 337                                                 modules[i].name);
 338                                 goto error;
 339                         } else {
 340                                 DBG("Unable to load optional module %s; continuing",
 341                                                 modules[i].name);
 342                                 ret = 0;
 343                         }
 344                 } else {
 345                         DBG("Modprobe successfully %s", modules[i].name);
 346                         modules[i].loaded = true;
 347                 }
 348         }
 349
 350 error:
 351         return ret;
 352 }
 353
 354 static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 355                 int entries, int required)
 356 {
 357         int ret = 0, i;
 358         char modprobe[256];
 359
 360         for (i = entries - 1; i >= 0; i--) {
 361                 if (!modules[i].loaded) {
 362                         continue;
 363                 }
 364                 ret = snprintf(modprobe, sizeof(modprobe),
 365                                 "/sbin/modprobe -r -q %s",
 366                                 modules[i].name);
 367                 if (ret < 0) {
 368                         PERROR("snprintf modprobe -r");
 369                         return;
 370                 }
 371                 modprobe[sizeof(modprobe) - 1] = '\0';
 372                 ret = system(modprobe);
 373                 if (ret == -1) {
 374                         ERR("Unable to launch modprobe -r for module %s",
 375                                         modules[i].name);
 376                 } else if (required && WEXITSTATUS(ret) != 0) {
 377                         ERR("Unable to remove module %s",
 378                                         modules[i].name);
 379                 } else {
 380                         DBG("Modprobe removal successful %s",
 381                                         modules[i].name);
 382                 }
 383         }
 384 }
 385
 386 #endif /* HAVE_KMOD */
 387
 388 /*
 389  * Remove control kernel module(s) in reverse load order.
 390  */
 391 void modprobe_remove_lttng_control(void)
 392 {
 393         modprobe_remove_lttng(kern_modules_control_core,
 394                               ARRAY_SIZE(kern_modules_control_core),
 395                               LTTNG_MOD_REQUIRED);
 396 }
 397
 398 static void free_probes(void)
 399 {
 400         int i;
 401
 402         if (!probes) {
 403                 return;
 404         }
 405         for (i = 0; i < nr_probes; ++i) {
 406                 free(probes[i].name);
 407         }
 408         free(probes);
 409         probes = NULL;
 410         nr_probes = 0;
 411 }
 412
 413 /*
 414  * Remove data kernel modules in reverse load order.
 415  */
 416 void modprobe_remove_lttng_data(void)
 417 {
 418         if (!probes) {
 419                 return;
 420         }
 421         modprobe_remove_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 422         free_probes();
 423 }
 424
 425 /*
 426  * Remove all kernel modules in reverse order.
 427  */
 428 void modprobe_remove_lttng_all(void)
 429 {
 430         modprobe_remove_lttng_data();
 431         modprobe_remove_lttng_control();
 432 }
 433
 434 /*
 435  * Load control kernel module(s).
 436  */
 437 int modprobe_lttng_control(void)
 438 {
 439         int ret;
 440
 441         ret = modprobe_lttng(kern_modules_control_core,
 442                              ARRAY_SIZE(kern_modules_control_core),
 443                              LTTNG_MOD_REQUIRED);
 444         return ret;
 445 }
 446
 447 /**
 448  * Grow global list of probes (double capacity or set it to 1 if
 449  * currently 0 and copy existing data).
 450  */
 451 static int grow_probes(void)
 452 {
 453         int i;
 454         struct kern_modules_param *tmp_probes;
 455
 456         /* Initialize capacity to 1 if 0. */
 457         if (probes_capacity == 0) {
 458                 probes = zmalloc(sizeof(*probes));
 459                 if (!probes) {
 460                         PERROR("malloc probe list");
 461                         return -ENOMEM;
 462                 }
 463
 464                 probes_capacity = 1;
 465                 return 0;
 466         }
 467
 468         /* Double size. */
 469         probes_capacity *= 2;
 470
 471         tmp_probes = zmalloc(sizeof(*tmp_probes) * probes_capacity);
 472         if (!tmp_probes) {
 473                 PERROR("malloc probe list");
 474                 return -ENOMEM;
 475         }
 476
 477         for (i = 0; i < nr_probes; ++i) {
 478                 /* Move name pointer. */
 479                 tmp_probes[i].name = probes[i].name;
 480         }
 481
 482         /* Replace probes with larger copy. */
 483         free(probes);
 484         probes = tmp_probes;
 485
 486         return 0;
 487 }
 488
 489 /*
 490  * Appends a comma-separated list of probes to the global list
 491  * of probes.
 492  */
 493 static int append_list_to_probes(const char *list)
 494 {
 495         char *next;
 496         int ret;
 497         char *tmp_list, *cur_list;
 498
 499         assert(list);
 500
 501         cur_list = tmp_list = strdup(list);
 502         if (!tmp_list) {
 503                 PERROR("strdup temp list");
 504                 return -ENOMEM;
 505         }
 506
 507         for (;;) {
 508                 size_t name_len;
 509                 struct kern_modules_param *cur_mod;
 510
 511                 next = strtok(cur_list, ",");
 512                 if (!next) {
 513                         break;
 514                 }
 515                 cur_list = NULL;
 516
 517                 /* filter leading spaces */
 518                 while (*next == ' ') {
 519                         next++;
 520                 }
 521
 522                 if (probes_capacity <= nr_probes) {
 523                         ret = grow_probes();
 524                         if (ret) {
 525                                 goto error;
 526                         }
 527                 }
 528
 529                 /* Length 13 is "lttng-probe-" + \0 */
 530                 name_len = strlen(next) + 13;
 531
 532                 cur_mod = &probes[nr_probes];
 533                 cur_mod->name = zmalloc(name_len);
 534                 if (!cur_mod->name) {
 535                         PERROR("malloc probe list");
 536                         ret = -ENOMEM;
 537                         goto error;
 538                 }
 539
 540                 ret = snprintf(cur_mod->name, name_len, "lttng-probe-%s", next);
 541                 if (ret < 0) {
 542                         PERROR("snprintf modprobe name");
 543                         ret = -ENOMEM;
 544                         goto error;
 545                 }
 546
 547                 nr_probes++;
 548         }
 549
 550         free(tmp_list);
 551         return 0;
 552
 553 error:
 554         free(tmp_list);
 555         free_probes();
 556         return ret;
 557 }
 558
 559 /*
 560  * Load data kernel module(s).
 561  */
 562 int modprobe_lttng_data(void)
 563 {
 564         int ret, i;
 565         char *list;
 566
 567         /*
 568          * Base probes: either from command line option, environment
 569          * variable or default list.
 570          */
 571         if (kmod_probes_list) {
 572                 list = kmod_probes_list;
 573         } else {
 574                 list = utils_get_kmod_probes_list();
 575         }
 576
 577         if (list) {
 578                 /* User-specified probes. */
 579                 ret = append_list_to_probes(list);
 580                 if (ret) {
 581                         return ret;
 582                 }
 583         } else {
 584                 /* Default probes. */
 585                 int def_len = ARRAY_SIZE(kern_modules_probes_default);
 586
 587                 probes = zmalloc(sizeof(*probes) * def_len);
 588                 if (!probes) {
 589                         PERROR("malloc probe list");
 590                         return -ENOMEM;
 591                 }
 592
 593                 nr_probes = probes_capacity = def_len;
 594
 595                 for (i = 0; i < def_len; ++i) {
 596                         char* name = strdup(kern_modules_probes_default[i].name);
 597
 598                         if (!name) {
 599                                 PERROR("strdup probe item");
 600                                 ret = -ENOMEM;
 601                                 goto error;
 602                         }
 603
 604                         probes[i].name = name;
 605                 }
 606         }
 607
 608         /*
 609          * Extra modules? Append them to current probes list.
 610          */
 611         if (kmod_extra_probes_list) {
 612                 list = kmod_extra_probes_list;
 613         } else {
 614                 list = utils_get_extra_kmod_probes_list();
 615         }
 616
 617         if (list) {
 618                 ret = append_list_to_probes(list);
 619                 if (ret) {
 620                         goto error;
 621                 }
 622         }
 623
 624         /*
 625          * Load probes modules now.
 626          */
 627         ret = modprobe_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 628         if (ret) {
 629                 goto error;
 630         }
 631         return ret;
 632
 633 error:
 634         free_probes();
 635         return ret;
 636 }