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