sdt.c revision 299001
1238384Sjkim/* 2238384Sjkim * CDDL HEADER START 3238384Sjkim * 4296341Sdelphij * The contents of this file are subject to the terms of the 5296341Sdelphij * Common Development and Distribution License (the "License"). 6296341Sdelphij * You may not use this file except in compliance with the License. 7296341Sdelphij * 8296341Sdelphij * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9296341Sdelphij * or http://www.opensolaris.org/os/licensing. 10296341Sdelphij * See the License for the specific language governing permissions 11296341Sdelphij * and limitations under the License. 12296341Sdelphij * 13296341Sdelphij * When distributing Covered Code, include this CDDL HEADER in each 14296341Sdelphij * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15296341Sdelphij * If applicable, add the following below this CDDL HEADER, with the 16296341Sdelphij * fields enclosed by brackets "[]" replaced with your own identifying 17296341Sdelphij * information: Portions Copyright [yyyy] [name of copyright owner] 18296341Sdelphij * 19296341Sdelphij * CDDL HEADER END 20238384Sjkim * 21296341Sdelphij * Portions Copyright 2006-2008 John Birrell jb@freebsd.org 22238384Sjkim * 23296341Sdelphij * $FreeBSD: stable/10/sys/cddl/dev/sdt/sdt.c 299001 2016-05-03 19:42:58Z markj $ 24296341Sdelphij * 25296341Sdelphij */ 26296341Sdelphij 27296341Sdelphij/* 28238384Sjkim * This file contains a reimplementation of the statically-defined tracing (SDT) 29238384Sjkim * framework for DTrace. Probes and SDT providers are defined using the macros 30238384Sjkim * in sys/sdt.h, which append all the needed structures to linker sets. When 31296341Sdelphij * this module is loaded, it iterates over all of the loaded modules and 32296341Sdelphij * registers probes and providers with the DTrace framework based on the 33296341Sdelphij * contents of these linker sets. 34296341Sdelphij * 35296341Sdelphij * A list of SDT providers is maintained here since a provider may span multiple 36296341Sdelphij * modules. When a kernel module is unloaded, a provider defined in that module 37296341Sdelphij * is unregistered only if no other modules refer to it. The DTrace framework is 38296341Sdelphij * responsible for destroying individual probes when a kernel module is 39296341Sdelphij * unloaded; in particular, probes may not span multiple kernel modules. 40296341Sdelphij */ 41296341Sdelphij 42296341Sdelphij#include "opt_kdtrace.h" 43296341Sdelphij 44296341Sdelphij#include <sys/cdefs.h> 45296341Sdelphij#include <sys/param.h> 46296341Sdelphij#include <sys/systm.h> 47296341Sdelphij 48296341Sdelphij#include <sys/conf.h> 49296341Sdelphij#include <sys/eventhandler.h> 50296341Sdelphij#include <sys/kernel.h> 51296341Sdelphij#include <sys/limits.h> 52296341Sdelphij#include <sys/linker.h> 53296341Sdelphij#include <sys/linker_set.h> 54296341Sdelphij#include <sys/lock.h> 55238384Sjkim#include <sys/malloc.h> 56296341Sdelphij#include <sys/module.h> 57238384Sjkim#include <sys/mutex.h> 58296341Sdelphij#include <sys/queue.h> 59296341Sdelphij#include <sys/sdt.h> 60296341Sdelphij 61296341Sdelphij#include <sys/dtrace.h> 62296341Sdelphij#include <sys/dtrace_bsd.h> 63238384Sjkim 64238384Sjkim/* DTrace methods. */ 65238384Sjkimstatic void sdt_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *); 66296341Sdelphijstatic void sdt_provide_probes(void *, dtrace_probedesc_t *); 67296341Sdelphijstatic void sdt_destroy(void *, dtrace_id_t, void *); 68296341Sdelphijstatic void sdt_enable(void *, dtrace_id_t, void *); 69296341Sdelphijstatic void sdt_disable(void *, dtrace_id_t, void *); 70296341Sdelphij 71296341Sdelphijstatic void sdt_load(void); 72296341Sdelphijstatic int sdt_unload(void); 73296341Sdelphijstatic void sdt_create_provider(struct sdt_provider *); 74296341Sdelphijstatic void sdt_create_probe(struct sdt_probe *); 75296341Sdelphijstatic void sdt_kld_load(void *, struct linker_file *); 76296341Sdelphijstatic void sdt_kld_unload_try(void *, struct linker_file *, int *); 77296341Sdelphij 78296341Sdelphijstatic MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers"); 79296341Sdelphij 80296341Sdelphijstatic dtrace_pattr_t sdt_attr = { 81296341Sdelphij{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 82296341Sdelphij{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 83296341Sdelphij{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA }, 84296341Sdelphij{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 85296341Sdelphij{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA }, 86296341Sdelphij}; 87296341Sdelphij 88296341Sdelphijstatic dtrace_pops_t sdt_pops = { 89296341Sdelphij sdt_provide_probes, 90296341Sdelphij NULL, 91296341Sdelphij sdt_enable, 92296341Sdelphij sdt_disable, 93296341Sdelphij NULL, 94296341Sdelphij NULL, 95296341Sdelphij sdt_getargdesc, 96296341Sdelphij NULL, 97296341Sdelphij NULL, 98238384Sjkim sdt_destroy, 99296341Sdelphij}; 100238384Sjkim 101296341Sdelphijstatic TAILQ_HEAD(, sdt_provider) sdt_prov_list; 102296341Sdelphij 103296341Sdelphijstatic eventhandler_tag sdt_kld_load_tag; 104296341Sdelphijstatic eventhandler_tag sdt_kld_unload_try_tag; 105296341Sdelphij 106238384Sjkimstatic void 107238384Sjkimsdt_create_provider(struct sdt_provider *prov) 108238384Sjkim{ 109296341Sdelphij struct sdt_provider *curr, *newprov; 110296341Sdelphij 111296341Sdelphij TAILQ_FOREACH(curr, &sdt_prov_list, prov_entry) 112296341Sdelphij if (strcmp(prov->name, curr->name) == 0) { 113296341Sdelphij /* The provider has already been defined. */ 114296341Sdelphij curr->sdt_refs++; 115296341Sdelphij return; 116296341Sdelphij } 117296341Sdelphij 118296341Sdelphij /* 119296341Sdelphij * Make a copy of prov so that we don't lose fields if its module is 120296341Sdelphij * unloaded but the provider isn't destroyed. This could happen with 121296341Sdelphij * a provider that spans multiple modules. 122296341Sdelphij */ 123296341Sdelphij newprov = malloc(sizeof(*newprov), M_SDT, M_WAITOK | M_ZERO); 124296341Sdelphij newprov->name = strdup(prov->name, M_SDT); 125296341Sdelphij prov->sdt_refs = newprov->sdt_refs = 1; 126296341Sdelphij 127296341Sdelphij TAILQ_INSERT_TAIL(&sdt_prov_list, newprov, prov_entry); 128296341Sdelphij 129296341Sdelphij (void)dtrace_register(newprov->name, &sdt_attr, DTRACE_PRIV_USER, NULL, 130296341Sdelphij &sdt_pops, NULL, (dtrace_provider_id_t *)&newprov->id); 131296341Sdelphij prov->id = newprov->id; 132296341Sdelphij} 133296341Sdelphij 134296341Sdelphijstatic void 135296341Sdelphijsdt_create_probe(struct sdt_probe *probe) 136296341Sdelphij{ 137296341Sdelphij struct sdt_provider *prov; 138296341Sdelphij char mod[DTRACE_MODNAMELEN]; 139296341Sdelphij char func[DTRACE_FUNCNAMELEN]; 140296341Sdelphij char name[DTRACE_NAMELEN]; 141296341Sdelphij const char *from; 142296341Sdelphij char *to; 143296341Sdelphij size_t len; 144296341Sdelphij 145296341Sdelphij if (probe->version != (int)sizeof(*probe)) { 146296341Sdelphij printf("ignoring probe %p, version %u expected %u\n", 147296341Sdelphij probe, probe->version, (int)sizeof(*probe)); 148296341Sdelphij return; 149296341Sdelphij } 150296341Sdelphij 151296341Sdelphij TAILQ_FOREACH(prov, &sdt_prov_list, prov_entry) 152296341Sdelphij if (strcmp(prov->name, probe->prov->name) == 0) 153296341Sdelphij break; 154296341Sdelphij 155296341Sdelphij KASSERT(prov != NULL, ("probe defined without a provider")); 156296341Sdelphij 157238384Sjkim /* If no module name was specified, use the module filename. */ 158296341Sdelphij if (*probe->mod == 0) { 159238384Sjkim len = strlcpy(mod, probe->sdtp_lf->filename, sizeof(mod)); 160296341Sdelphij if (len > 3 && strcmp(mod + len - 3, ".ko") == 0) 161296341Sdelphij mod[len - 3] = '\0'; 162296341Sdelphij } else 163296341Sdelphij strlcpy(mod, probe->mod, sizeof(mod)); 164296341Sdelphij 165238384Sjkim /* 166238384Sjkim * Unfortunately this is necessary because the Solaris DTrace 167238384Sjkim * code mixes consts and non-consts with casts to override 168296341Sdelphij * the incompatibilies. On FreeBSD, we use strict warnings 169296341Sdelphij * in the C compiler, so we have to respect const vs non-const. 170296341Sdelphij */ 171296341Sdelphij strlcpy(func, probe->func, sizeof(func)); 172296341Sdelphij if (func[0] == '\0') 173296341Sdelphij strcpy(func, "none"); 174296341Sdelphij 175296341Sdelphij from = probe->name; 176296341Sdelphij to = name; 177296341Sdelphij for (len = 0; len < (sizeof(name) - 1) && *from != '\0'; 178296341Sdelphij len++, from++, to++) { 179296341Sdelphij if (from[0] == '_' && from[1] == '_') { 180296341Sdelphij *to = '-'; 181296341Sdelphij from++; 182296341Sdelphij } else 183296341Sdelphij *to = *from; 184296341Sdelphij } 185296341Sdelphij *to = '\0'; 186296341Sdelphij 187296341Sdelphij if (dtrace_probe_lookup(prov->id, mod, func, name) != DTRACE_IDNONE) 188296341Sdelphij return; 189296341Sdelphij 190296341Sdelphij (void)dtrace_probe_create(prov->id, mod, func, name, 1, probe); 191296341Sdelphij} 192296341Sdelphij 193296341Sdelphij/* 194296341Sdelphij * Probes are created through the SDT module load/unload hook, so this function 195296341Sdelphij * has nothing to do. It only exists because the DTrace provider framework 196296341Sdelphij * requires one of provide_probes and provide_module to be defined. 197296341Sdelphij */ 198296341Sdelphijstatic void 199296341Sdelphijsdt_provide_probes(void *arg, dtrace_probedesc_t *desc) 200296341Sdelphij{ 201296341Sdelphij} 202296341Sdelphij 203296341Sdelphijstatic void 204296341Sdelphijsdt_enable(void *arg __unused, dtrace_id_t id, void *parg) 205296341Sdelphij{ 206296341Sdelphij struct sdt_probe *probe = parg; 207296341Sdelphij 208296341Sdelphij probe->id = id; 209296341Sdelphij probe->sdtp_lf->nenabled++; 210296341Sdelphij} 211296341Sdelphij 212296341Sdelphijstatic void 213296341Sdelphijsdt_disable(void *arg __unused, dtrace_id_t id, void *parg) 214296341Sdelphij{ 215296341Sdelphij struct sdt_probe *probe = parg; 216296341Sdelphij 217296341Sdelphij KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled")); 218296341Sdelphij 219296341Sdelphij probe->id = 0; 220296341Sdelphij probe->sdtp_lf->nenabled--; 221296341Sdelphij} 222296341Sdelphij 223296341Sdelphijstatic void 224296341Sdelphijsdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc) 225296341Sdelphij{ 226296341Sdelphij struct sdt_argtype *argtype; 227296341Sdelphij struct sdt_probe *probe = parg; 228296341Sdelphij 229296341Sdelphij if (desc->dtargd_ndx >= probe->n_args) { 230296341Sdelphij desc->dtargd_ndx = DTRACE_ARGNONE; 231296341Sdelphij return; 232238384Sjkim } 233296341Sdelphij 234238384Sjkim TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) { 235296341Sdelphij if (desc->dtargd_ndx == argtype->ndx) { 236296341Sdelphij desc->dtargd_mapping = desc->dtargd_ndx; 237296341Sdelphij if (argtype->type == NULL) { 238296341Sdelphij desc->dtargd_native[0] = '\0'; 239296341Sdelphij desc->dtargd_xlate[0] = '\0'; 240238384Sjkim continue; 241238384Sjkim } 242238384Sjkim strlcpy(desc->dtargd_native, argtype->type, 243296341Sdelphij sizeof(desc->dtargd_native)); 244296341Sdelphij if (argtype->xtype != NULL) 245296341Sdelphij strlcpy(desc->dtargd_xlate, argtype->xtype, 246296341Sdelphij sizeof(desc->dtargd_xlate)); 247296341Sdelphij } 248296341Sdelphij } 249296341Sdelphij} 250296341Sdelphij 251296341Sdelphijstatic void 252296341Sdelphijsdt_destroy(void *arg, dtrace_id_t id, void *parg) 253296341Sdelphij{ 254296341Sdelphij} 255296341Sdelphij 256296341Sdelphij/* 257296341Sdelphij * Called from the kernel linker when a module is loaded, before 258296341Sdelphij * dtrace_module_loaded() is called. This is done so that it's possible to 259296341Sdelphij * register new providers when modules are loaded. The DTrace framework 260296341Sdelphij * explicitly disallows calling into the framework from the provide_module 261296341Sdelphij * provider method, so we cannot do this there. 262296341Sdelphij */ 263296341Sdelphijstatic void 264296341Sdelphijsdt_kld_load(void *arg __unused, struct linker_file *lf) 265296341Sdelphij{ 266296341Sdelphij struct sdt_provider **prov, **begin, **end; 267296341Sdelphij struct sdt_probe **probe, **p_begin, **p_end; 268296341Sdelphij struct sdt_argtype **argtype, **a_begin, **a_end; 269296341Sdelphij 270296341Sdelphij if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end, 271296341Sdelphij NULL) == 0) { 272296341Sdelphij for (prov = begin; prov < end; prov++) 273296341Sdelphij sdt_create_provider(*prov); 274296341Sdelphij } 275296341Sdelphij 276296341Sdelphij if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end, 277296341Sdelphij NULL) == 0) { 278296341Sdelphij for (probe = p_begin; probe < p_end; probe++) { 279296341Sdelphij (*probe)->sdtp_lf = lf; 280296341Sdelphij sdt_create_probe(*probe); 281296341Sdelphij TAILQ_INIT(&(*probe)->argtype_list); 282296341Sdelphij } 283296341Sdelphij } 284296341Sdelphij 285296341Sdelphij if (linker_file_lookup_set(lf, "sdt_argtypes_set", &a_begin, &a_end, 286296341Sdelphij NULL) == 0) { 287296341Sdelphij for (argtype = a_begin; argtype < a_end; argtype++) { 288296341Sdelphij (*argtype)->probe->n_args++; 289296341Sdelphij TAILQ_INSERT_TAIL(&(*argtype)->probe->argtype_list, 290296341Sdelphij *argtype, argtype_entry); 291296341Sdelphij } 292296341Sdelphij } 293296341Sdelphij} 294296341Sdelphij 295296341Sdelphijstatic void 296296341Sdelphijsdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error) 297296341Sdelphij{ 298296341Sdelphij struct sdt_provider *prov, **curr, **begin, **end, *tmp; 299296341Sdelphij 300296341Sdelphij if (*error != 0) 301296341Sdelphij /* We already have an error, so don't do anything. */ 302296341Sdelphij return; 303296341Sdelphij else if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end, 304296341Sdelphij NULL)) 305296341Sdelphij /* No DTrace providers are declared in this file. */ 306296341Sdelphij return; 307296341Sdelphij 308296341Sdelphij /* 309296341Sdelphij * Go through all the providers declared in this linker file and 310296341Sdelphij * unregister any that aren't declared in another loaded file. 311296341Sdelphij */ 312296341Sdelphij for (curr = begin; curr < end; curr++) { 313296341Sdelphij TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) { 314296341Sdelphij if (strcmp(prov->name, (*curr)->name) != 0) 315296341Sdelphij continue; 316296341Sdelphij 317296341Sdelphij if (prov->sdt_refs == 1) { 318296341Sdelphij if (dtrace_unregister(prov->id) != 0) { 319296341Sdelphij *error = 1; 320296341Sdelphij return; 321296341Sdelphij } 322296341Sdelphij TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry); 323296341Sdelphij free(prov->name, M_SDT); 324296341Sdelphij free(prov, M_SDT); 325296341Sdelphij } else 326296341Sdelphij prov->sdt_refs--; 327296341Sdelphij break; 328296341Sdelphij } 329296341Sdelphij } 330296341Sdelphij} 331296341Sdelphij 332296341Sdelphijstatic int 333296341Sdelphijsdt_linker_file_cb(linker_file_t lf, void *arg __unused) 334296341Sdelphij{ 335296341Sdelphij 336296341Sdelphij sdt_kld_load(NULL, lf); 337296341Sdelphij 338296341Sdelphij return (0); 339238384Sjkim} 340296341Sdelphij 341238384Sjkimstatic void 342296341Sdelphijsdt_load() 343296341Sdelphij{ 344296341Sdelphij 345296341Sdelphij TAILQ_INIT(&sdt_prov_list); 346296341Sdelphij 347238384Sjkim sdt_probe_func = dtrace_probe; 348238384Sjkim 349238384Sjkim sdt_kld_load_tag = EVENTHANDLER_REGISTER(kld_load, sdt_kld_load, NULL, 350296341Sdelphij EVENTHANDLER_PRI_ANY); 351296341Sdelphij sdt_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try, 352296341Sdelphij sdt_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY); 353296341Sdelphij 354296341Sdelphij /* Pick up probes from the kernel and already-loaded linker files. */ 355296341Sdelphij linker_file_foreach(sdt_linker_file_cb, NULL); 356296341Sdelphij} 357296341Sdelphij 358296341Sdelphijstatic int 359296341Sdelphijsdt_unload() 360296341Sdelphij{ 361296341Sdelphij struct sdt_provider *prov, *tmp; 362296341Sdelphij int ret; 363296341Sdelphij 364296341Sdelphij EVENTHANDLER_DEREGISTER(kld_load, sdt_kld_load_tag); 365296341Sdelphij EVENTHANDLER_DEREGISTER(kld_unload_try, sdt_kld_unload_try_tag); 366296341Sdelphij 367296341Sdelphij sdt_probe_func = sdt_probe_stub; 368296341Sdelphij 369296341Sdelphij TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) { 370296341Sdelphij ret = dtrace_unregister(prov->id); 371296341Sdelphij if (ret != 0) 372296341Sdelphij return (ret); 373296341Sdelphij TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry); 374296341Sdelphij free(prov->name, M_SDT); 375296341Sdelphij free(prov, M_SDT); 376296341Sdelphij } 377296341Sdelphij 378296341Sdelphij return (0); 379296341Sdelphij} 380296341Sdelphij 381296341Sdelphijstatic int 382296341Sdelphijsdt_modevent(module_t mod __unused, int type, void *data __unused) 383296341Sdelphij{ 384296341Sdelphij 385296341Sdelphij switch (type) { 386296341Sdelphij case MOD_LOAD: 387296341Sdelphij case MOD_UNLOAD: 388296341Sdelphij case MOD_SHUTDOWN: 389296341Sdelphij return (0); 390296341Sdelphij default: 391296341Sdelphij return (EOPNOTSUPP); 392296341Sdelphij } 393296341Sdelphij} 394296341Sdelphij 395296341SdelphijSYSINIT(sdt_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_load, NULL); 396296341SdelphijSYSUNINIT(sdt_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_unload, NULL); 397296341Sdelphij 398296341SdelphijDEV_MODULE(sdt, sdt_modevent, NULL); 399296341SdelphijMODULE_VERSION(sdt, 1); 400296341SdelphijMODULE_DEPEND(sdt, dtrace, 1, 1, 1); 401296341Sdelphij