tools/perf/util/thread.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "../perf.h"
   3 #include <errno.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <linux/kernel.h>
   8 #include "session.h"
   9 #include "thread.h"
  10 #include "thread-stack.h"
  11 #include "util.h"
  12 #include "debug.h"
  13 #include "namespaces.h"
  14 #include "comm.h"
  15 #include "map.h"
  16 #include "symbol.h"
  17 #include "unwind.h"
  18
  19 #include <api/fs/fs.h>
  20
  21 int thread__init_map_groups(struct thread *thread, struct machine *machine)
  22 {
  23         pid_t pid = thread->pid_;
  24
  25         if (pid == thread->tid || pid == -1) {
  26                 thread->mg = map_groups__new(machine);
  27         } else {
  28                 struct thread *leader = __machine__findnew_thread(machine, pid, pid);
  29                 if (leader) {
  30                         thread->mg = map_groups__get(leader->mg);
  31                         thread__put(leader);
  32                 }
  33         }
  34
  35         return thread->mg ? 0 : -1;
  36 }
  37
  38 struct thread *thread__new(pid_t pid, pid_t tid)
  39 {
  40         char *comm_str;
  41         struct comm *comm;
  42         struct thread *thread = zalloc(sizeof(*thread));
  43
  44         if (thread != NULL) {
  45                 thread->pid_ = pid;
  46                 thread->tid = tid;
  47                 thread->ppid = -1;
  48                 thread->cpu = -1;
  49                 INIT_LIST_HEAD(&thread->namespaces_list);
  50                 INIT_LIST_HEAD(&thread->comm_list);
  51                 init_rwsem(&thread->namespaces_lock);
  52                 init_rwsem(&thread->comm_lock);
  53
  54                 comm_str = malloc(32);
  55                 if (!comm_str)
  56                         goto err_thread;
  57
  58                 snprintf(comm_str, 32, ":%d", tid);
  59                 comm = comm__new(comm_str, 0, false);
  60                 free(comm_str);
  61                 if (!comm)
  62                         goto err_thread;
  63
  64                 list_add(&comm->list, &thread->comm_list);
  65                 refcount_set(&thread->refcnt, 1);
  66                 RB_CLEAR_NODE(&thread->rb_node);
  67                 /* Thread holds first ref to nsdata. */
  68                 thread->nsinfo = nsinfo__new(pid);
  69                 srccode_state_init(&thread->srccode_state);
  70         }
  71
  72         return thread;
  73
  74 err_thread:
  75         free(thread);
  76         return NULL;
  77 }
  78
  79 void thread__delete(struct thread *thread)
  80 {
  81         struct namespaces *namespaces, *tmp_namespaces;
  82         struct comm *comm, *tmp_comm;
  83
  84         BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
  85
  86         thread_stack__free(thread);
  87
  88         if (thread->mg) {
  89                 map_groups__put(thread->mg);
  90                 thread->mg = NULL;
  91         }
  92         down_write(&thread->namespaces_lock);
  93         list_for_each_entry_safe(namespaces, tmp_namespaces,
  94                                  &thread->namespaces_list, list) {
  95                 list_del(&namespaces->list);
  96                 namespaces__free(namespaces);
  97         }
  98         up_write(&thread->namespaces_lock);
  99
 100         down_write(&thread->comm_lock);
 101         list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
 102                 list_del(&comm->list);
 103                 comm__free(comm);
 104         }
 105         up_write(&thread->comm_lock);
 106
 107         unwind__finish_access(thread);
 108         nsinfo__zput(thread->nsinfo);
 109         srccode_state_free(&thread->srccode_state);
 110
 111         exit_rwsem(&thread->namespaces_lock);
 112         exit_rwsem(&thread->comm_lock);
 113         free(thread);
 114 }
 115
 116 struct thread *thread__get(struct thread *thread)
 117 {
 118         if (thread)
 119                 refcount_inc(&thread->refcnt);
 120         return thread;
 121 }
 122
 123 void thread__put(struct thread *thread)
 124 {
 125         if (thread && refcount_dec_and_test(&thread->refcnt)) {
 126                 /*
 127                  * Remove it from the dead_threads list, as last reference
 128                  * is gone.
 129                  */
 130                 list_del_init(&thread->node);
 131                 thread__delete(thread);
 132         }
 133 }
 134
 135 struct namespaces *thread__namespaces(const struct thread *thread)
 136 {
 137         if (list_empty(&thread->namespaces_list))
 138                 return NULL;
 139
 140         return list_first_entry(&thread->namespaces_list, struct namespaces, list);
 141 }
 142
 143 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
 144                                     struct namespaces_event *event)
 145 {
 146         struct namespaces *new, *curr = thread__namespaces(thread);
 147
 148         new = namespaces__new(event);
 149         if (!new)
 150                 return -ENOMEM;
 151
 152         list_add(&new->list, &thread->namespaces_list);
 153
 154         if (timestamp && curr) {
 155                 /*
 156                  * setns syscall must have changed few or all the namespaces
 157                  * of this thread. Update end time for the namespaces
 158                  * previously used.
 159                  */
 160                 curr = list_next_entry(new, list);
 161                 curr->end_time = timestamp;
 162         }
 163
 164         return 0;
 165 }
 166
 167 int thread__set_namespaces(struct thread *thread, u64 timestamp,
 168                            struct namespaces_event *event)
 169 {
 170         int ret;
 171
 172         down_write(&thread->namespaces_lock);
 173         ret = __thread__set_namespaces(thread, timestamp, event);
 174         up_write(&thread->namespaces_lock);
 175         return ret;
 176 }
 177
 178 struct comm *thread__comm(const struct thread *thread)
 179 {
 180         if (list_empty(&thread->comm_list))
 181                 return NULL;
 182
 183         return list_first_entry(&thread->comm_list, struct comm, list);
 184 }
 185
 186 struct comm *thread__exec_comm(const struct thread *thread)
 187 {
 188         struct comm *comm, *last = NULL;
 189
 190         list_for_each_entry(comm, &thread->comm_list, list) {
 191                 if (comm->exec)
 192                         return comm;
 193                 last = comm;
 194         }
 195
 196         return last;
 197 }
 198
 199 static int ____thread__set_comm(struct thread *thread, const char *str,
 200                                 u64 timestamp, bool exec)
 201 {
 202         struct comm *new, *curr = thread__comm(thread);
 203
 204         /* Override the default :tid entry */
 205         if (!thread->comm_set) {
 206                 int err = comm__override(curr, str, timestamp, exec);
 207                 if (err)
 208                         return err;
 209         } else {
 210                 new = comm__new(str, timestamp, exec);
 211                 if (!new)
 212                         return -ENOMEM;
 213                 list_add(&new->list, &thread->comm_list);
 214
 215                 if (exec)
 216                         unwind__flush_access(thread);
 217         }
 218
 219         thread->comm_set = true;
 220
 221         return 0;
 222 }
 223
 224 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 225                        bool exec)
 226 {
 227         int ret;
 228
 229         down_write(&thread->comm_lock);
 230         ret = ____thread__set_comm(thread, str, timestamp, exec);
 231         up_write(&thread->comm_lock);
 232         return ret;
 233 }
 234
 235 int thread__set_comm_from_proc(struct thread *thread)
 236 {
 237         char path[64];
 238         char *comm = NULL;
 239         size_t sz;
 240         int err = -1;
 241
 242         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 243                        thread->pid_, thread->tid) >= (int)sizeof(path)) &&
 244             procfs__read_str(path, &comm, &sz) == 0) {
 245                 comm[sz - 1] = '\0';
 246                 err = thread__set_comm(thread, comm, 0);
 247         }
 248
 249         return err;
 250 }
 251
 252 static const char *__thread__comm_str(const struct thread *thread)
 253 {
 254         const struct comm *comm = thread__comm(thread);
 255
 256         if (!comm)
 257                 return NULL;
 258
 259         return comm__str(comm);
 260 }
 261
 262 const char *thread__comm_str(const struct thread *thread)
 263 {
 264         const char *str;
 265
 266         down_read((struct rw_semaphore *)&thread->comm_lock);
 267         str = __thread__comm_str(thread);
 268         up_read((struct rw_semaphore *)&thread->comm_lock);
 269
 270         return str;
 271 }
 272
 273 /* CHECKME: it should probably better return the max comm len from its comm list */
 274 int thread__comm_len(struct thread *thread)
 275 {
 276         if (!thread->comm_len) {
 277                 const char *comm = thread__comm_str(thread);
 278                 if (!comm)
 279                         return 0;
 280                 thread->comm_len = strlen(comm);
 281         }
 282
 283         return thread->comm_len;
 284 }
 285
 286 size_t thread__fprintf(struct thread *thread, FILE *fp)
 287 {
 288         return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
 289                map_groups__fprintf(thread->mg, fp);
 290 }
 291
 292 int thread__insert_map(struct thread *thread, struct map *map)
 293 {
 294         int ret;
 295
 296         ret = unwind__prepare_access(thread, map, NULL);
 297         if (ret)
 298                 return ret;
 299
 300         map_groups__fixup_overlappings(thread->mg, map, stderr);
 301         map_groups__insert(thread->mg, map);
 302
 303         return 0;
 304 }
 305
 306 static int __thread__prepare_access(struct thread *thread)
 307 {
 308         bool initialized = false;
 309         int err = 0;
 310         struct maps *maps = &thread->mg->maps;
 311         struct map *map;
 312
 313         down_read(&maps->lock);
 314
 315         for (map = maps__first(maps); map; map = map__next(map)) {
 316                 err = unwind__prepare_access(thread, map, &initialized);
 317                 if (err || initialized)
 318                         break;
 319         }
 320
 321         up_read(&maps->lock);
 322
 323         return err;
 324 }
 325
 326 static int thread__prepare_access(struct thread *thread)
 327 {
 328         int err = 0;
 329
 330         if (symbol_conf.use_callchain)
 331                 err = __thread__prepare_access(thread);
 332
 333         return err;
 334 }
 335
 336 static int thread__clone_map_groups(struct thread *thread,
 337                                     struct thread *parent,
 338                                     bool do_maps_clone)
 339 {
 340         /* This is new thread, we share map groups for process. */
 341         if (thread->pid_ == parent->pid_)
 342                 return thread__prepare_access(thread);
 343
 344         if (thread->mg == parent->mg) {
 345                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 346                          thread->pid_, thread->tid, parent->pid_, parent->tid);
 347                 return 0;
 348         }
 349         /* But this one is new process, copy maps. */
 350         return do_maps_clone ? map_groups__clone(thread, parent->mg) : 0;
 351 }
 352
 353 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
 354 {
 355         if (parent->comm_set) {
 356                 const char *comm = thread__comm_str(parent);
 357                 int err;
 358                 if (!comm)
 359                         return -ENOMEM;
 360                 err = thread__set_comm(thread, comm, timestamp);
 361                 if (err)
 362                         return err;
 363         }
 364
 365         thread->ppid = parent->tid;
 366         return thread__clone_map_groups(thread, parent, do_maps_clone);
 367 }
 368
 369 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
 370                                         struct addr_location *al)
 371 {
 372         size_t i;
 373         const u8 cpumodes[] = {
 374                 PERF_RECORD_MISC_USER,
 375                 PERF_RECORD_MISC_KERNEL,
 376                 PERF_RECORD_MISC_GUEST_USER,
 377                 PERF_RECORD_MISC_GUEST_KERNEL
 378         };
 379
 380         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 381                 thread__find_symbol(thread, cpumodes[i], addr, al);
 382                 if (al->map)
 383                         break;
 384         }
 385 }
 386
 387 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 388 {
 389         if (thread->pid_ == thread->tid)
 390                 return thread__get(thread);
 391
 392         if (thread->pid_ == -1)
 393                 return NULL;
 394
 395         return machine__find_thread(machine, thread->pid_, thread->pid_);
 396 }
 397
 398 int thread__memcpy(struct thread *thread, struct machine *machine,
 399                    void *buf, u64 ip, int len, bool *is64bit)
 400 {
 401        u8 cpumode = PERF_RECORD_MISC_USER;
 402        struct addr_location al;
 403        long offset;
 404
 405        if (machine__kernel_ip(machine, ip))
 406                cpumode = PERF_RECORD_MISC_KERNEL;
 407
 408        if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso ||
 409            al.map->dso->data.status == DSO_DATA_STATUS_ERROR ||
 410            map__load(al.map) < 0)
 411                return -1;
 412
 413        offset = al.map->map_ip(al.map, ip);
 414        if (is64bit)
 415                *is64bit = al.map->dso->is_64_bit;
 416
 417        return dso__data_read_offset(al.map->dso, machine, offset, buf, len);
 418 }