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 #define _GNU_SOURCE
  20 #define _LGPL_SOURCE
  21 #include <assert.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <sys/wait.h>
  25
  26 #include <common/common.h>
  27 #include <common/utils.h>
  28
  29 #include "modprobe.h"
  30 #include "kern-modules.h"
  31
  32 #define LTTNG_MOD_REQUIRED      1
  33 #define LTTNG_MOD_OPTIONAL      0
  34
  35 /* LTTng kernel tracer mandatory core modules list */
  36 struct kern_modules_param kern_modules_control_core[] = {
  37         { "lttng-tracer" },     /* MUST be loaded first so keep at top */
  38         { "lttng-lib-ring-buffer" },
  39         { "lttng-ring-buffer-client-discard" },
  40         { "lttng-ring-buffer-client-overwrite" },
  41         { "lttng-ring-buffer-metadata-client" },
  42         { "lttng-ring-buffer-client-mmap-discard" },
  43         { "lttng-ring-buffer-client-mmap-overwrite" },
  44         { "lttng-ring-buffer-metadata-mmap-client" },
  45 };
  46
  47 /* LTTng kernel tracer optional base modules list */
  48 struct kern_modules_param kern_modules_control_opt[] = {
  49         { "lttng-types" },
  50         { "lttng-ftrace" },
  51         { "lttng-kprobes" },
  52         { "lttng-kretprobes" },
  53 };
  54
  55 /* LTTng kernel tracer probe modules list */
  56 struct kern_modules_param kern_modules_probes_default[] = {
  57         { "lttng-probe-asoc" },
  58         { "lttng-probe-block" },
  59         { "lttng-probe-btrfs" },
  60         { "lttng-probe-compaction" },
  61         { "lttng-probe-ext3" },
  62         { "lttng-probe-ext4" },
  63         { "lttng-probe-gpio" },
  64         { "lttng-probe-irq" },
  65         { "lttng-probe-jbd" },
  66         { "lttng-probe-jbd2" },
  67         { "lttng-probe-kmem" },
  68         { "lttng-probe-kvm" },
  69         { "lttng-probe-kvm-x86" },
  70         { "lttng-probe-kvm-x86-mmu" },
  71         { "lttng-probe-lock" },
  72         { "lttng-probe-module" },
  73         { "lttng-probe-napi" },
  74         { "lttng-probe-net" },
  75         { "lttng-probe-power" },
  76         { "lttng-probe-printk" },
  77         { "lttng-probe-random" },
  78         { "lttng-probe-rcu" },
  79         { "lttng-probe-regmap" },
  80         { "lttng-probe-regulator" },
  81         { "lttng-probe-rpm" },
  82         { "lttng-probe-sched" },
  83         { "lttng-probe-scsi" },
  84         { "lttng-probe-signal" },
  85         { "lttng-probe-skb" },
  86         { "lttng-probe-sock" },
  87         { "lttng-probe-statedump" },
  88         { "lttng-probe-sunrpc" },
  89         { "lttng-probe-timer" },
  90         { "lttng-probe-udp" },
  91         { "lttng-probe-vmscan" },
  92         { "lttng-probe-v4l2" },
  93         { "lttng-probe-workqueue" },
  94         { "lttng-probe-writeback" },
  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 static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 103                 int entries, int required)
 104 {
 105         int ret = 0, i;
 106         char modprobe[256];
 107
 108         for (i = entries - 1; i >= 0; i--) {
 109                 ret = snprintf(modprobe, sizeof(modprobe),
 110                                 "/sbin/modprobe -r -q %s",
 111                                 modules[i].name);
 112                 if (ret < 0) {
 113                         PERROR("snprintf modprobe -r");
 114                         return;
 115                 }
 116                 modprobe[sizeof(modprobe) - 1] = '\0';
 117                 ret = system(modprobe);
 118                 if (ret == -1) {
 119                         ERR("Unable to launch modprobe -r for module %s",
 120                                         modules[i].name);
 121                 } else if (required && WEXITSTATUS(ret) != 0) {
 122                         ERR("Unable to remove module %s",
 123                                         modules[i].name);
 124                 } else {
 125                         DBG("Modprobe removal successful %s",
 126                                         modules[i].name);
 127                 }
 128         }
 129 }
 130
 131 /*
 132  * Remove control kernel module(s) in reverse load order.
 133  */
 134 void modprobe_remove_lttng_control(void)
 135 {
 136         modprobe_remove_lttng(kern_modules_control_opt,
 137                               ARRAY_SIZE(kern_modules_control_opt),
 138                               LTTNG_MOD_OPTIONAL);
 139         modprobe_remove_lttng(kern_modules_control_core,
 140                               ARRAY_SIZE(kern_modules_control_core),
 141                               LTTNG_MOD_REQUIRED);
 142 }
 143
 144 static void free_probes(void)
 145 {
 146         int i;
 147
 148         if (!probes) {
 149                 return;
 150         }
 151         for (i = 0; i < nr_probes; ++i) {
 152                 free(probes[i].name);
 153         }
 154         free(probes);
 155         probes = NULL;
 156         nr_probes = 0;
 157 }
 158
 159 /*
 160  * Remove data kernel modules in reverse load order.
 161  */
 162 void modprobe_remove_lttng_data(void)
 163 {
 164         if (!probes) {
 165                 return;
 166         }
 167         modprobe_remove_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 168         free_probes();
 169 }
 170
 171 /*
 172  * Remove all kernel modules in reverse order.
 173  */
 174 void modprobe_remove_lttng_all(void)
 175 {
 176         modprobe_remove_lttng_data();
 177         modprobe_remove_lttng_control();
 178 }
 179
 180 #if HAVE_KMOD
 181 #include <libkmod.h>
 182 static void log_kmod(void *data, int priority, const char *file, int line,
 183                 const char *fn, const char *format, va_list args)
 184 {
 185         char *str;
 186
 187         if (vasprintf(&str, format, args) < 0) {
 188                 return;
 189         }
 190
 191         DBG("libkmod: %s", str);
 192         free(str);
 193 }
 194 static int modprobe_lttng(struct kern_modules_param *modules,
 195                 int entries, int required)
 196 {
 197         int ret = 0, i;
 198         struct kmod_ctx *ctx;
 199
 200         ctx = kmod_new(NULL, NULL);
 201         if (!ctx) {
 202                 PERROR("Unable to create kmod library context");
 203                 ret = -ENOMEM;
 204                 goto error;
 205         }
 206
 207         kmod_set_log_fn(ctx, log_kmod, NULL);
 208         kmod_load_resources(ctx);
 209
 210         for (i = 0; i < entries; i++) {
 211                 struct kmod_module *mod = NULL;
 212
 213                 ret = kmod_module_new_from_name(ctx, modules[i].name, &mod);
 214                 if (ret < 0) {
 215                         PERROR("Failed to create kmod module for %s", modules[i].name);
 216                         goto error;
 217                 }
 218
 219                 ret = kmod_module_probe_insert_module(mod, KMOD_PROBE_IGNORE_LOADED,
 220                                 NULL, NULL, NULL, NULL);
 221                 if (ret < 0) {
 222                         if (required) {
 223                                 ERR("Unable to load required module %s",
 224                                                 modules[i].name);
 225                                 goto error;
 226                         } else {
 227                                 DBG("Unable to load optional module %s; continuing",
 228                                                 modules[i].name);
 229                                 ret = 0;
 230                         }
 231                 } else {
 232                         DBG("Modprobe successfully %s", modules[i].name);
 233                 }
 234
 235                 kmod_module_unref(mod);
 236         }
 237
 238 error:
 239         if (ctx) {
 240                 kmod_unref(ctx);
 241         }
 242         return ret;
 243 }
 244
 245 #else /* HAVE_KMOD */
 246
 247 static int modprobe_lttng(struct kern_modules_param *modules,
 248                 int entries, int required)
 249 {
 250         int ret = 0, i;
 251         char modprobe[256];
 252
 253         for (i = 0; i < entries; i++) {
 254                 ret = snprintf(modprobe, sizeof(modprobe),
 255                                 "/sbin/modprobe %s%s",
 256                                 required ? "" : "-q ",
 257                                 modules[i].name);
 258                 if (ret < 0) {
 259                         PERROR("snprintf modprobe");
 260                         goto error;
 261                 }
 262                 modprobe[sizeof(modprobe) - 1] = '\0';
 263                 ret = system(modprobe);
 264                 if (ret == -1) {
 265                         if (required) {
 266                                 ERR("Unable to launch modprobe for required module %s",
 267                                                 modules[i].name);
 268                                 goto error;
 269                         } else {
 270                                 DBG("Unable to launch modprobe for optional module %s; continuing",
 271                                                 modules[i].name);
 272                                 ret = 0;
 273                         }
 274                 } else if (WEXITSTATUS(ret) != 0) {
 275                         if (required) {
 276                                 ERR("Unable to load required module %s",
 277                                                 modules[i].name);
 278                                 goto error;
 279                         } else {
 280                                 DBG("Unable to load optional module %s; continuing",
 281                                                 modules[i].name);
 282                                 ret = 0;
 283                         }
 284                 } else {
 285                         DBG("Modprobe successfully %s", modules[i].name);
 286                 }
 287         }
 288
 289 error:
 290         return ret;
 291 }
 292
 293 #endif /* HAVE_KMOD */
 294
 295 /*
 296  * Load control kernel module(s).
 297  */
 298 int modprobe_lttng_control(void)
 299 {
 300         int ret;
 301
 302         ret = modprobe_lttng(kern_modules_control_core,
 303                              ARRAY_SIZE(kern_modules_control_core),
 304                              LTTNG_MOD_REQUIRED);
 305         if (ret != 0)
 306                 return ret;
 307         ret = modprobe_lttng(kern_modules_control_opt,
 308                              ARRAY_SIZE(kern_modules_control_opt),
 309                              LTTNG_MOD_OPTIONAL);
 310         return ret;
 311 }
 312
 313 /**
 314  * Grow global list of probes (double capacity or set it to 1 if
 315  * currently 0 and copy existing data).
 316  */
 317 static int grow_probes(void)
 318 {
 319         int i;
 320         struct kern_modules_param *tmp_probes;
 321
 322         /* Initialize capacity to 1 if 0. */
 323         if (probes_capacity == 0) {
 324                 probes = zmalloc(sizeof(*probes));
 325                 if (!probes) {
 326                         PERROR("malloc probe list");
 327                         return -ENOMEM;
 328                 }
 329
 330                 probes_capacity = 1;
 331                 return 0;
 332         }
 333
 334         /* Double size. */
 335         probes_capacity *= 2;
 336
 337         tmp_probes = zmalloc(sizeof(*tmp_probes) * probes_capacity);
 338         if (!tmp_probes) {
 339                 PERROR("malloc probe list");
 340                 return -ENOMEM;
 341         }
 342
 343         for (i = 0; i < nr_probes; ++i) {
 344                 /* Move name pointer. */
 345                 tmp_probes[i].name = probes[i].name;
 346         }
 347
 348         /* Replace probes with larger copy. */
 349         free(probes);
 350         probes = tmp_probes;
 351
 352         return 0;
 353 }
 354
 355 /*
 356  * Appends a comma-separated list of probes to the global list
 357  * of probes.
 358  */
 359 static int append_list_to_probes(const char *list)
 360 {
 361         char *next;
 362         int ret;
 363         char *tmp_list, *cur_list;
 364
 365         assert(list);
 366
 367         cur_list = tmp_list = strdup(list);
 368         if (!tmp_list) {
 369                 PERROR("strdup temp list");
 370                 return -ENOMEM;
 371         }
 372
 373         for (;;) {
 374                 size_t name_len;
 375                 struct kern_modules_param *cur_mod;
 376
 377                 next = strtok(cur_list, ",");
 378                 if (!next) {
 379                         break;
 380                 }
 381                 cur_list = NULL;
 382
 383                 /* filter leading spaces */
 384                 while (*next == ' ') {
 385                         next++;
 386                 }
 387
 388                 if (probes_capacity <= nr_probes) {
 389                         ret = grow_probes();
 390                         if (ret) {
 391                                 goto error;
 392                         }
 393                 }
 394
 395                 /* Length 13 is "lttng-probe-" + \0 */
 396                 name_len = strlen(next) + 13;
 397
 398                 cur_mod = &probes[nr_probes];
 399                 cur_mod->name = zmalloc(name_len);
 400                 if (!cur_mod->name) {
 401                         PERROR("malloc probe list");
 402                         ret = -ENOMEM;
 403                         goto error;
 404                 }
 405
 406                 ret = snprintf(cur_mod->name, name_len, "lttng-probe-%s", next);
 407                 if (ret < 0) {
 408                         PERROR("snprintf modprobe name");
 409                         ret = -ENOMEM;
 410                         goto error;
 411                 }
 412
 413                 nr_probes++;
 414         }
 415
 416         free(tmp_list);
 417         return 0;
 418
 419 error:
 420         free(tmp_list);
 421         free_probes();
 422         return ret;
 423 }
 424
 425 /*
 426  * Load data kernel module(s).
 427  */
 428 int modprobe_lttng_data(void)
 429 {
 430         int ret, i;
 431         char *list;
 432
 433         /*
 434          * Base probes: either from command line option, environment
 435          * variable or default list.
 436          */
 437         if (kmod_probes_list) {
 438                 list = kmod_probes_list;
 439         } else {
 440                 list = utils_get_kmod_probes_list();
 441         }
 442
 443         if (list) {
 444                 /* User-specified probes. */
 445                 ret = append_list_to_probes(list);
 446                 if (ret) {
 447                         return ret;
 448                 }
 449         } else {
 450                 /* Default probes. */
 451                 int def_len = ARRAY_SIZE(kern_modules_probes_default);
 452
 453                 probes = zmalloc(sizeof(*probes) * def_len);
 454                 if (!probes) {
 455                         PERROR("malloc probe list");
 456                         return -ENOMEM;
 457                 }
 458
 459                 nr_probes = probes_capacity = def_len;
 460
 461                 for (i = 0; i < def_len; ++i) {
 462                         char* name = strdup(kern_modules_probes_default[i].name);
 463
 464                         if (!name) {
 465                                 PERROR("strdup probe item");
 466                                 ret = -ENOMEM;
 467                                 goto error;
 468                         }
 469
 470                         probes[i].name = name;
 471                 }
 472         }
 473
 474         /*
 475          * Extra modules? Append them to current probes list.
 476          */
 477         if (kmod_extra_probes_list) {
 478                 list = kmod_extra_probes_list;
 479         } else {
 480                 list = utils_get_extra_kmod_probes_list();
 481         }
 482
 483         if (list) {
 484                 ret = append_list_to_probes(list);
 485                 if (ret) {
 486                         goto error;
 487                 }
 488         }
 489
 490         /*
 491          * Load probes modules now.
 492          */
 493         ret = modprobe_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 494         if (ret) {
 495                 goto error;
 496         }
 497         return ret;
 498
 499 error:
 500         free_probes();
 501         return ret;
 502 }