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 (required && ret < 0) {
 213                         ERR("Unable to load module %s", modules[i].name);
 214                 } else {
 215                         DBG("Modprobe successfully %s", modules[i].name);
 216                 }
 217
 218                 kmod_module_unref(mod);
 219         }
 220
 221 error:
 222         if (ctx) {
 223                 kmod_unref(ctx);
 224         }
 225         return ret;
 226 }
 227
 228 #else /* HAVE_KMOD */
 229
 230 static int modprobe_lttng(struct kern_modules_param *modules,
 231                 int entries, int required)
 232 {
 233         int ret = 0, i;
 234         char modprobe[256];
 235
 236         for (i = 0; i < entries; i++) {
 237                 ret = snprintf(modprobe, sizeof(modprobe),
 238                                 "/sbin/modprobe %s%s",
 239                                 required ? "" : "-q ",
 240                                 modules[i].name);
 241                 if (ret < 0) {
 242                         PERROR("snprintf modprobe");
 243                         goto error;
 244                 }
 245                 modprobe[sizeof(modprobe) - 1] = '\0';
 246                 ret = system(modprobe);
 247                 if (ret == -1) {
 248                         ERR("Unable to launch modprobe for module %s",
 249                                         modules[i].name);
 250                 } else if (required && WEXITSTATUS(ret) != 0) {
 251                         ERR("Unable to load module %s", modules[i].name);
 252                 } else {
 253                         DBG("Modprobe successfully %s", modules[i].name);
 254                 }
 255         }
 256
 257 error:
 258         return ret;
 259 }
 260
 261 #endif /* HAVE_KMOD */
 262
 263 /*
 264  * Load control kernel module(s).
 265  */
 266 int modprobe_lttng_control(void)
 267 {
 268         int ret;
 269
 270         ret = modprobe_lttng(kern_modules_control_core,
 271                              ARRAY_SIZE(kern_modules_control_core),
 272                              LTTNG_MOD_REQUIRED);
 273         if (ret != 0)
 274                 return ret;
 275         ret = modprobe_lttng(kern_modules_control_opt,
 276                              ARRAY_SIZE(kern_modules_control_opt),
 277                              LTTNG_MOD_OPTIONAL);
 278         return ret;
 279 }
 280
 281 /**
 282  * Grow global list of probes (double capacity or set it to 1 if
 283  * currently 0 and copy existing data).
 284  */
 285 static int grow_probes(void)
 286 {
 287         int i;
 288         struct kern_modules_param *tmp_probes;
 289
 290         /* Initialize capacity to 1 if 0. */
 291         if (probes_capacity == 0) {
 292                 probes = zmalloc(sizeof(*probes));
 293                 if (!probes) {
 294                         PERROR("malloc probe list");
 295                         return -ENOMEM;
 296                 }
 297
 298                 probes_capacity = 1;
 299                 return 0;
 300         }
 301
 302         /* Double size. */
 303         probes_capacity *= 2;
 304
 305         tmp_probes = zmalloc(sizeof(*tmp_probes) * probes_capacity);
 306         if (!tmp_probes) {
 307                 PERROR("malloc probe list");
 308                 return -ENOMEM;
 309         }
 310
 311         for (i = 0; i < nr_probes; ++i) {
 312                 /* Move name pointer. */
 313                 tmp_probes[i].name = probes[i].name;
 314         }
 315
 316         /* Replace probes with larger copy. */
 317         free(probes);
 318         probes = tmp_probes;
 319
 320         return 0;
 321 }
 322
 323 /*
 324  * Appends a comma-separated list of probes to the global list
 325  * of probes.
 326  */
 327 static int append_list_to_probes(const char *list)
 328 {
 329         char *next;
 330         int index = nr_probes, ret;
 331
 332         assert(list);
 333
 334         char *tmp_list = strdup(list);
 335         if (!tmp_list) {
 336                 PERROR("strdup temp list");
 337                 return -ENOMEM;
 338         }
 339
 340         for (;;) {
 341                 size_t name_len;
 342                 struct kern_modules_param *cur_mod;
 343
 344                 next = strtok(tmp_list, ",");
 345                 if (!next) {
 346                         break;
 347                 }
 348                 tmp_list = NULL;
 349
 350                 /* filter leading spaces */
 351                 while (*next == ' ') {
 352                         next++;
 353                 }
 354
 355                 if (probes_capacity <= nr_probes) {
 356                         ret = grow_probes();
 357                         if (ret) {
 358                                 return ret;
 359                         }
 360                 }
 361
 362                 /* Length 13 is "lttng-probe-" + \0 */
 363                 name_len = strlen(next) + 13;
 364
 365                 cur_mod = &probes[index];
 366                 cur_mod->name = zmalloc(name_len);
 367                 if (!cur_mod->name) {
 368                         PERROR("malloc probe list");
 369                         return -ENOMEM;
 370                 }
 371
 372                 ret = snprintf(cur_mod->name, name_len, "lttng-probe-%s", next);
 373                 if (ret < 0) {
 374                         PERROR("snprintf modprobe name");
 375                         return -ENOMEM;
 376                 }
 377
 378                 cur_mod++;
 379                 nr_probes++;
 380         }
 381
 382         free(tmp_list);
 383
 384         return 0;
 385 }
 386
 387 /*
 388  * Load data kernel module(s).
 389  */
 390 int modprobe_lttng_data(void)
 391 {
 392         int ret, i;
 393         char *list;
 394
 395         /*
 396          * Base probes: either from command line option, environment
 397          * variable or default list.
 398          */
 399         if (kmod_probes_list) {
 400                 list = kmod_probes_list;
 401         } else {
 402                 list = utils_get_kmod_probes_list();
 403         }
 404
 405         if (list) {
 406                 /* User-specified probes. */
 407                 ret = append_list_to_probes(list);
 408
 409                 if (ret) {
 410                         return ret;
 411                 }
 412         } else {
 413                 /* Default probes. */
 414                 int def_len = ARRAY_SIZE(kern_modules_probes_default);
 415                 probes = zmalloc(sizeof(*probes) * def_len);
 416
 417                 if (!probes) {
 418                         PERROR("malloc probe list");
 419                         return -ENOMEM;
 420                 }
 421
 422                 nr_probes = probes_capacity = def_len;
 423
 424                 for (i = 0; i < def_len; ++i) {
 425                         char* name = strdup(kern_modules_probes_default[i].name);
 426
 427                         if (!name) {
 428                                 PERROR("strdup probe item");
 429                                 return -ENOMEM;
 430                         }
 431
 432                         probes[i].name = name;
 433                 }
 434         }
 435
 436         /*
 437          * Extra modules? Append them to current probes list.
 438          */
 439         if (kmod_extra_probes_list) {
 440                 list = kmod_extra_probes_list;
 441         } else {
 442                 list = utils_get_extra_kmod_probes_list();
 443         }
 444
 445         if (list) {
 446                 ret = append_list_to_probes(list);
 447                 if (ret) {
 448                         return ret;
 449                 }
 450         }
 451
 452         /*
 453          * Load probes modules now.
 454          */
 455         return modprobe_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 456 }