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