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                 }
 202
 203                 kmod_module_unref(mod);
 204         }
 205
 206 error:
 207         if (ctx) {
 208                 kmod_unref(ctx);
 209         }
 210         return ret;
 211 }
 212
 213 /**
 214  * @brief Recursively unload modules.
 215  *
 216  * This function implements the same modules unloading behavior as
 217  * 'modprobe -r' or rmmod, it will recursevily go trought the \p module
 218  * dependencies and unload modules with a refcount of 0.
 219  *
 220  * @param mod           The module to unload
 221  *
 222  * @returns             \c 0 on success
 223  *                      \c < 0 on error
 224  */
 225 static int rmmod_recurse(struct kmod_module *mod) {
 226         int ret = 0;
 227         struct kmod_list *deps, *itr;
 228
 229         if (kmod_module_get_initstate(mod) == KMOD_MODULE_BUILTIN) {
 230                 DBG("Module %s is builtin", kmod_module_get_name(mod));
 231                 return ret;
 232         }
 233
 234         ret = kmod_module_remove_module(mod, 0);
 235
 236         deps = kmod_module_get_dependencies(mod);
 237         if (deps != NULL) {
 238                 kmod_list_foreach(itr, deps) {
 239                         struct kmod_module *dep = kmod_module_get_module(itr);
 240                         if (kmod_module_get_refcnt(dep) == 0) {
 241                                 DBG("Recursive remove module %s",
 242                                                 kmod_module_get_name(dep));
 243                                 rmmod_recurse(dep);
 244                         }
 245                         kmod_module_unref(dep);
 246                 }
 247                 kmod_module_unref_list(deps);
 248         }
 249
 250         return ret;
 251 }
 252
 253 /**
 254  * @brief Unloads the kernel modules in \p modules
 255  *
 256  * @param modules       List of modules to unload
 257  * @param entries       Number of modules in the list
 258  * @param required      Are the modules required or optionnal
 259  *
 260  */
 261 static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 262                 int entries, int required)
 263 {
 264         int ret = 0, i;
 265         struct kmod_ctx *ctx;
 266
 267         ret = setup_kmod_ctx(&ctx);
 268         if (ret < 0) {
 269                 goto error;
 270         }
 271
 272         for (i = entries - 1; i >= 0; i--) {
 273                 struct kmod_module *mod = NULL;
 274
 275                 ret = kmod_module_new_from_name(ctx, modules[i].name, &mod);
 276                 if (ret < 0) {
 277                         PERROR("Failed to create kmod module for %s", modules[i].name);
 278                         goto error;
 279                 }
 280
 281                 ret = rmmod_recurse(mod);
 282                 if (ret == -EEXIST) {
 283                         DBG("Module %s is not in kernel.", modules[i].name);
 284                 } else if (required && ret < 0) {
 285                         ERR("Unable to remove module %s", modules[i].name);
 286                 } else {
 287                         DBG("Modprobe removal successful %s",
 288                                 modules[i].name);
 289                 }
 290
 291                 kmod_module_unref(mod);
 292         }
 293
 294 error:
 295         if (ctx) {
 296                 kmod_unref(ctx);
 297         }
 298 }
 299
 300 #else /* HAVE_KMOD */
 301
 302 static int modprobe_lttng(struct kern_modules_param *modules,
 303                 int entries, int required)
 304 {
 305         int ret = 0, i;
 306         char modprobe[256];
 307
 308         for (i = 0; i < entries; i++) {
 309                 ret = snprintf(modprobe, sizeof(modprobe),
 310                                 "/sbin/modprobe %s%s",
 311                                 required ? "" : "-q ",
 312                                 modules[i].name);
 313                 if (ret < 0) {
 314                         PERROR("snprintf modprobe");
 315                         goto error;
 316                 }
 317                 modprobe[sizeof(modprobe) - 1] = '\0';
 318                 ret = system(modprobe);
 319                 if (ret == -1) {
 320                         if (required) {
 321                                 ERR("Unable to launch modprobe for required module %s",
 322                                                 modules[i].name);
 323                                 goto error;
 324                         } else {
 325                                 DBG("Unable to launch modprobe for optional module %s; continuing",
 326                                                 modules[i].name);
 327                                 ret = 0;
 328                         }
 329                 } else if (WEXITSTATUS(ret) != 0) {
 330                         if (required) {
 331                                 ERR("Unable to load required module %s",
 332                                                 modules[i].name);
 333                                 goto error;
 334                         } else {
 335                                 DBG("Unable to load optional module %s; continuing",
 336                                                 modules[i].name);
 337                                 ret = 0;
 338                         }
 339                 } else {
 340                         DBG("Modprobe successfully %s", modules[i].name);
 341                 }
 342         }
 343
 344 error:
 345         return ret;
 346 }
 347
 348 static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 349                 int entries, int required)
 350 {
 351         int ret = 0, i;
 352         char modprobe[256];
 353
 354         for (i = entries - 1; i >= 0; i--) {
 355                 ret = snprintf(modprobe, sizeof(modprobe),
 356                                 "/sbin/modprobe -r -q %s",
 357                                 modules[i].name);
 358                 if (ret < 0) {
 359                         PERROR("snprintf modprobe -r");
 360                         return;
 361                 }
 362                 modprobe[sizeof(modprobe) - 1] = '\0';
 363                 ret = system(modprobe);
 364                 if (ret == -1) {
 365                         ERR("Unable to launch modprobe -r for module %s",
 366                                         modules[i].name);
 367                 } else if (required && WEXITSTATUS(ret) != 0) {
 368                         ERR("Unable to remove module %s",
 369                                         modules[i].name);
 370                 } else {
 371                         DBG("Modprobe removal successful %s",
 372                                         modules[i].name);
 373                 }
 374         }
 375 }
 376
 377 #endif /* HAVE_KMOD */
 378
 379 /*
 380  * Remove control kernel module(s) in reverse load order.
 381  */
 382 void modprobe_remove_lttng_control(void)
 383 {
 384         modprobe_remove_lttng(kern_modules_control_core,
 385                               ARRAY_SIZE(kern_modules_control_core),
 386                               LTTNG_MOD_REQUIRED);
 387 }
 388
 389 static void free_probes(void)
 390 {
 391         int i;
 392
 393         if (!probes) {
 394                 return;
 395         }
 396         for (i = 0; i < nr_probes; ++i) {
 397                 free(probes[i].name);
 398         }
 399         free(probes);
 400         probes = NULL;
 401         nr_probes = 0;
 402 }
 403
 404 /*
 405  * Remove data kernel modules in reverse load order.
 406  */
 407 void modprobe_remove_lttng_data(void)
 408 {
 409         if (!probes) {
 410                 return;
 411         }
 412         modprobe_remove_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 413         free_probes();
 414 }
 415
 416 /*
 417  * Remove all kernel modules in reverse order.
 418  */
 419 void modprobe_remove_lttng_all(void)
 420 {
 421         modprobe_remove_lttng_data();
 422         modprobe_remove_lttng_control();
 423 }
 424
 425 /*
 426  * Load control kernel module(s).
 427  */
 428 int modprobe_lttng_control(void)
 429 {
 430         int ret;
 431
 432         ret = modprobe_lttng(kern_modules_control_core,
 433                              ARRAY_SIZE(kern_modules_control_core),
 434                              LTTNG_MOD_REQUIRED);
 435         return ret;
 436 }
 437
 438 /**
 439  * Grow global list of probes (double capacity or set it to 1 if
 440  * currently 0 and copy existing data).
 441  */
 442 static int grow_probes(void)
 443 {
 444         int i;
 445         struct kern_modules_param *tmp_probes;
 446
 447         /* Initialize capacity to 1 if 0. */
 448         if (probes_capacity == 0) {
 449                 probes = zmalloc(sizeof(*probes));
 450                 if (!probes) {
 451                         PERROR("malloc probe list");
 452                         return -ENOMEM;
 453                 }
 454
 455                 probes_capacity = 1;
 456                 return 0;
 457         }
 458
 459         /* Double size. */
 460         probes_capacity *= 2;
 461
 462         tmp_probes = zmalloc(sizeof(*tmp_probes) * probes_capacity);
 463         if (!tmp_probes) {
 464                 PERROR("malloc probe list");
 465                 return -ENOMEM;
 466         }
 467
 468         for (i = 0; i < nr_probes; ++i) {
 469                 /* Move name pointer. */
 470                 tmp_probes[i].name = probes[i].name;
 471         }
 472
 473         /* Replace probes with larger copy. */
 474         free(probes);
 475         probes = tmp_probes;
 476
 477         return 0;
 478 }
 479
 480 /*
 481  * Appends a comma-separated list of probes to the global list
 482  * of probes.
 483  */
 484 static int append_list_to_probes(const char *list)
 485 {
 486         char *next;
 487         int ret;
 488         char *tmp_list, *cur_list;
 489
 490         assert(list);
 491
 492         cur_list = tmp_list = strdup(list);
 493         if (!tmp_list) {
 494                 PERROR("strdup temp list");
 495                 return -ENOMEM;
 496         }
 497
 498         for (;;) {
 499                 size_t name_len;
 500                 struct kern_modules_param *cur_mod;
 501
 502                 next = strtok(cur_list, ",");
 503                 if (!next) {
 504                         break;
 505                 }
 506                 cur_list = NULL;
 507
 508                 /* filter leading spaces */
 509                 while (*next == ' ') {
 510                         next++;
 511                 }
 512
 513                 if (probes_capacity <= nr_probes) {
 514                         ret = grow_probes();
 515                         if (ret) {
 516                                 goto error;
 517                         }
 518                 }
 519
 520                 /* Length 13 is "lttng-probe-" + \0 */
 521                 name_len = strlen(next) + 13;
 522
 523                 cur_mod = &probes[nr_probes];
 524                 cur_mod->name = zmalloc(name_len);
 525                 if (!cur_mod->name) {
 526                         PERROR("malloc probe list");
 527                         ret = -ENOMEM;
 528                         goto error;
 529                 }
 530
 531                 ret = snprintf(cur_mod->name, name_len, "lttng-probe-%s", next);
 532                 if (ret < 0) {
 533                         PERROR("snprintf modprobe name");
 534                         ret = -ENOMEM;
 535                         goto error;
 536                 }
 537
 538                 nr_probes++;
 539         }
 540
 541         free(tmp_list);
 542         return 0;
 543
 544 error:
 545         free(tmp_list);
 546         free_probes();
 547         return ret;
 548 }
 549
 550 /*
 551  * Load data kernel module(s).
 552  */
 553 int modprobe_lttng_data(void)
 554 {
 555         int ret, i;
 556         char *list;
 557
 558         /*
 559          * Base probes: either from command line option, environment
 560          * variable or default list.
 561          */
 562         if (kmod_probes_list) {
 563                 list = kmod_probes_list;
 564         } else {
 565                 list = utils_get_kmod_probes_list();
 566         }
 567
 568         if (list) {
 569                 /* User-specified probes. */
 570                 ret = append_list_to_probes(list);
 571                 if (ret) {
 572                         return ret;
 573                 }
 574         } else {
 575                 /* Default probes. */
 576                 int def_len = ARRAY_SIZE(kern_modules_probes_default);
 577
 578                 probes = zmalloc(sizeof(*probes) * def_len);
 579                 if (!probes) {
 580                         PERROR("malloc probe list");
 581                         return -ENOMEM;
 582                 }
 583
 584                 nr_probes = probes_capacity = def_len;
 585
 586                 for (i = 0; i < def_len; ++i) {
 587                         char* name = strdup(kern_modules_probes_default[i].name);
 588
 589                         if (!name) {
 590                                 PERROR("strdup probe item");
 591                                 ret = -ENOMEM;
 592                                 goto error;
 593                         }
 594
 595                         probes[i].name = name;
 596                 }
 597         }
 598
 599         /*
 600          * Extra modules? Append them to current probes list.
 601          */
 602         if (kmod_extra_probes_list) {
 603                 list = kmod_extra_probes_list;
 604         } else {
 605                 list = utils_get_extra_kmod_probes_list();
 606         }
 607
 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 }