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 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 /*
 145  * Remove data kernel modules in reverse load order.
 146  */
 147 void modprobe_remove_lttng_data(void)
 148 {
 149         int i;
 150
 151         if (probes) {
 152                 modprobe_remove_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 153
 154                 for (i = 0; i < nr_probes; ++i) {
 155                         free(probes[i].name);
 156                 }
 157
 158                 free(probes);
 159                 probes = NULL;
 160         }
 161 }
 162
 163 /*
 164  * Remove all kernel modules in reverse order.
 165  */
 166 void modprobe_remove_lttng_all(void)
 167 {
 168         modprobe_remove_lttng_data();
 169         modprobe_remove_lttng_control();
 170 }
 171
 172 #if HAVE_KMOD
 173 #include <libkmod.h>
 174 static void log_kmod(void *data, int priority, const char *file, int line,
 175                 const char *fn, const char *format, va_list args)
 176 {
 177         char *str;
 178
 179         if (vasprintf(&str, format, args) < 0) {
 180                 return;
 181         }
 182
 183         DBG("libkmod: %s", str);
 184         free(str);
 185 }
 186 static int modprobe_lttng(struct kern_modules_param *modules,
 187                 int entries, int required)
 188 {
 189         int ret = 0, i;
 190         struct kmod_ctx *ctx;
 191
 192         ctx = kmod_new(NULL, NULL);
 193         if (!ctx) {
 194                 PERROR("Unable to create kmod library context");
 195                 ret = -ENOMEM;
 196                 goto error;
 197         }
 198
 199         kmod_set_log_fn(ctx, log_kmod, NULL);
 200         kmod_load_resources(ctx);
 201
 202         for (i = 0; i < entries; i++) {
 203                 struct kmod_module *mod = NULL;
 204
 205                 ret = kmod_module_new_from_name(ctx, modules[i].name, &mod);
 206                 if (ret < 0) {
 207                         PERROR("Failed to create kmod module for %s", modules[i].name);
 208                         goto error;
 209                 }
 210
 211                 ret = kmod_module_probe_insert_module(mod, KMOD_PROBE_IGNORE_LOADED,
 212                                 NULL, NULL, NULL, NULL);
 213                 if (ret < 0) {
 214                         if (required) {
 215                                 ERR("Unable to load required module %s",
 216                                                 modules[i].name);
 217                                 goto error;
 218                         } else {
 219                                 DBG("Unable to load optional module %s; continuing",
 220                                                 modules[i].name);
 221                                 ret = 0;
 222                         }
 223                 } else {
 224                         DBG("Modprobe successfully %s", modules[i].name);
 225                 }
 226
 227                 kmod_module_unref(mod);
 228         }
 229
 230 error:
 231         if (ctx) {
 232                 kmod_unref(ctx);
 233         }
 234         return ret;
 235 }
 236
 237 #else /* HAVE_KMOD */
 238
 239 static int modprobe_lttng(struct kern_modules_param *modules,
 240                 int entries, int required)
 241 {
 242         int ret = 0, i;
 243         char modprobe[256];
 244
 245         for (i = 0; i < entries; i++) {
 246                 ret = snprintf(modprobe, sizeof(modprobe),
 247                                 "/sbin/modprobe %s%s",
 248                                 required ? "" : "-q ",
 249                                 modules[i].name);
 250                 if (ret < 0) {
 251                         PERROR("snprintf modprobe");
 252                         goto error;
 253                 }
 254                 modprobe[sizeof(modprobe) - 1] = '\0';
 255                 ret = system(modprobe);
 256                 if (ret == -1) {
 257                         if (required) {
 258                                 ERR("Unable to launch modprobe for required module %s",
 259                                                 modules[i].name);
 260                                 goto error;
 261                         } else {
 262                                 DBG("Unable to launch modprobe for optional module %s; continuing",
 263                                                 modules[i].name);
 264                                 ret = 0;
 265                         }
 266                 } else if (WEXITSTATUS(ret) != 0) {
 267                         if (required) {
 268                                 ERR("Unable to load required module %s",
 269                                                 modules[i].name);
 270                                 goto error;
 271                         } else {
 272                                 DBG("Unable to load optional module %s; continuing",
 273                                                 modules[i].name);
 274                                 ret = 0;
 275                         }
 276                 } else {
 277                         DBG("Modprobe successfully %s", modules[i].name);
 278                 }
 279         }
 280
 281 error:
 282         return ret;
 283 }
 284
 285 #endif /* HAVE_KMOD */
 286
 287 /*
 288  * Load control kernel module(s).
 289  */
 290 int modprobe_lttng_control(void)
 291 {
 292         int ret;
 293
 294         ret = modprobe_lttng(kern_modules_control_core,
 295                              ARRAY_SIZE(kern_modules_control_core),
 296                              LTTNG_MOD_REQUIRED);
 297         if (ret != 0)
 298                 return ret;
 299         ret = modprobe_lttng(kern_modules_control_opt,
 300                              ARRAY_SIZE(kern_modules_control_opt),
 301                              LTTNG_MOD_OPTIONAL);
 302         return ret;
 303 }
 304
 305 /**
 306  * Grow global list of probes (double capacity or set it to 1 if
 307  * currently 0 and copy existing data).
 308  */
 309 static int grow_probes(void)
 310 {
 311         int i;
 312         struct kern_modules_param *tmp_probes;
 313
 314         /* Initialize capacity to 1 if 0. */
 315         if (probes_capacity == 0) {
 316                 probes = zmalloc(sizeof(*probes));
 317                 if (!probes) {
 318                         PERROR("malloc probe list");
 319                         return -ENOMEM;
 320                 }
 321
 322                 probes_capacity = 1;
 323                 return 0;
 324         }
 325
 326         /* Double size. */
 327         probes_capacity *= 2;
 328
 329         tmp_probes = zmalloc(sizeof(*tmp_probes) * probes_capacity);
 330         if (!tmp_probes) {
 331                 PERROR("malloc probe list");
 332                 return -ENOMEM;
 333         }
 334
 335         for (i = 0; i < nr_probes; ++i) {
 336                 /* Move name pointer. */
 337                 tmp_probes[i].name = probes[i].name;
 338         }
 339
 340         /* Replace probes with larger copy. */
 341         free(probes);
 342         probes = tmp_probes;
 343
 344         return 0;
 345 }
 346
 347 /*
 348  * Appends a comma-separated list of probes to the global list
 349  * of probes.
 350  */
 351 static int append_list_to_probes(const char *list)
 352 {
 353         char *next;
 354         int index = nr_probes, ret;
 355
 356         assert(list);
 357
 358         char *tmp_list = strdup(list);
 359         if (!tmp_list) {
 360                 PERROR("strdup temp list");
 361                 return -ENOMEM;
 362         }
 363
 364         for (;;) {
 365                 size_t name_len;
 366                 struct kern_modules_param *cur_mod;
 367
 368                 next = strtok(tmp_list, ",");
 369                 if (!next) {
 370                         break;
 371                 }
 372                 tmp_list = NULL;
 373
 374                 /* filter leading spaces */
 375                 while (*next == ' ') {
 376                         next++;
 377                 }
 378
 379                 if (probes_capacity <= nr_probes) {
 380                         ret = grow_probes();
 381                         if (ret) {
 382                                 return ret;
 383                         }
 384                 }
 385
 386                 /* Length 13 is "lttng-probe-" + \0 */
 387                 name_len = strlen(next) + 13;
 388
 389                 cur_mod = &probes[index];
 390                 cur_mod->name = zmalloc(name_len);
 391                 if (!cur_mod->name) {
 392                         PERROR("malloc probe list");
 393                         return -ENOMEM;
 394                 }
 395
 396                 ret = snprintf(cur_mod->name, name_len, "lttng-probe-%s", next);
 397                 if (ret < 0) {
 398                         PERROR("snprintf modprobe name");
 399                         return -ENOMEM;
 400                 }
 401
 402                 cur_mod++;
 403                 nr_probes++;
 404         }
 405
 406         free(tmp_list);
 407
 408         return 0;
 409 }
 410
 411 /*
 412  * Load data kernel module(s).
 413  */
 414 int modprobe_lttng_data(void)
 415 {
 416         int ret, i;
 417         char *list;
 418
 419         /*
 420          * Base probes: either from command line option, environment
 421          * variable or default list.
 422          */
 423         if (kmod_probes_list) {
 424                 list = kmod_probes_list;
 425         } else {
 426                 list = utils_get_kmod_probes_list();
 427         }
 428
 429         if (list) {
 430                 /* User-specified probes. */
 431                 ret = append_list_to_probes(list);
 432
 433                 if (ret) {
 434                         return ret;
 435                 }
 436         } else {
 437                 /* Default probes. */
 438                 int def_len = ARRAY_SIZE(kern_modules_probes_default);
 439                 probes = zmalloc(sizeof(*probes) * def_len);
 440
 441                 if (!probes) {
 442                         PERROR("malloc probe list");
 443                         return -ENOMEM;
 444                 }
 445
 446                 nr_probes = probes_capacity = def_len;
 447
 448                 for (i = 0; i < def_len; ++i) {
 449                         char* name = strdup(kern_modules_probes_default[i].name);
 450
 451                         if (!name) {
 452                                 PERROR("strdup probe item");
 453                                 return -ENOMEM;
 454                         }
 455
 456                         probes[i].name = name;
 457                 }
 458         }
 459
 460         /*
 461          * Extra modules? Append them to current probes list.
 462          */
 463         if (kmod_extra_probes_list) {
 464                 list = kmod_extra_probes_list;
 465         } else {
 466                 list = utils_get_extra_kmod_probes_list();
 467         }
 468
 469         if (list) {
 470                 ret = append_list_to_probes(list);
 471                 if (ret) {
 472                         return ret;
 473                 }
 474         }
 475
 476         /*
 477          * Load probes modules now.
 478          */
 479         return modprobe_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 480 }