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