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