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 static 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 struct namespaces *thread__namespaces(const struct thread *thread)
 144 {
 145         struct namespaces *ns;
 146
 147         down_read((struct rw_semaphore *)&thread->namespaces_lock);
 148         ns = __thread__namespaces(thread);
 149         up_read((struct rw_semaphore *)&thread->namespaces_lock);
 150
 151         return ns;
 152 }
 153
 154 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
 155                                     struct namespaces_event *event)
 156 {
 157         struct namespaces *new, *curr = __thread__namespaces(thread);
 158
 159         new = namespaces__new(event);
 160         if (!new)
 161                 return -ENOMEM;
 162
 163         list_add(&new->list, &thread->namespaces_list);
 164
 165         if (timestamp && curr) {
 166                 /*
 167                  * setns syscall must have changed few or all the namespaces
 168                  * of this thread. Update end time for the namespaces
 169                  * previously used.
 170                  */
 171                 curr = list_next_entry(new, list);
 172                 curr->end_time = timestamp;
 173         }
 174
 175         return 0;
 176 }
 177
 178 int thread__set_namespaces(struct thread *thread, u64 timestamp,
 179                            struct namespaces_event *event)
 180 {
 181         int ret;
 182
 183         down_write(&thread->namespaces_lock);
 184         ret = __thread__set_namespaces(thread, timestamp, event);
 185         up_write(&thread->namespaces_lock);
 186         return ret;
 187 }
 188
 189 struct comm *thread__comm(const struct thread *thread)
 190 {
 191         if (list_empty(&thread->comm_list))
 192                 return NULL;
 193
 194         return list_first_entry(&thread->comm_list, struct comm, list);
 195 }
 196
 197 struct comm *thread__exec_comm(const struct thread *thread)
 198 {
 199         struct comm *comm, *last = NULL;
 200
 201         list_for_each_entry(comm, &thread->comm_list, list) {
 202                 if (comm->exec)
 203                         return comm;
 204                 last = comm;
 205         }
 206
 207         return last;
 208 }
 209
 210 static int ____thread__set_comm(struct thread *thread, const char *str,
 211                                 u64 timestamp, bool exec)
 212 {
 213         struct comm *new, *curr = thread__comm(thread);
 214
 215         /* Override the default :tid entry */
 216         if (!thread->comm_set) {
 217                 int err = comm__override(curr, str, timestamp, exec);
 218                 if (err)
 219                         return err;
 220         } else {
 221                 new = comm__new(str, timestamp, exec);
 222                 if (!new)
 223                         return -ENOMEM;
 224                 list_add(&new->list, &thread->comm_list);
 225
 226                 if (exec)
 227                         unwind__flush_access(thread);
 228         }
 229
 230         thread->comm_set = true;
 231
 232         return 0;
 233 }
 234
 235 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 236                        bool exec)
 237 {
 238         int ret;
 239
 240         down_write(&thread->comm_lock);
 241         ret = ____thread__set_comm(thread, str, timestamp, exec);
 242         up_write(&thread->comm_lock);
 243         return ret;
 244 }
 245
 246 int thread__set_comm_from_proc(struct thread *thread)
 247 {
 248         char path[64];
 249         char *comm = NULL;
 250         size_t sz;
 251         int err = -1;
 252
 253         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 254                        thread->pid_, thread->tid) >= (int)sizeof(path)) &&
 255             procfs__read_str(path, &comm, &sz) == 0) {
 256                 comm[sz - 1] = '\0';
 257                 err = thread__set_comm(thread, comm, 0);
 258         }
 259
 260         return err;
 261 }
 262
 263 static const char *__thread__comm_str(const struct thread *thread)
 264 {
 265         const struct comm *comm = thread__comm(thread);
 266
 267         if (!comm)
 268                 return NULL;
 269
 270         return comm__str(comm);
 271 }
 272
 273 const char *thread__comm_str(const struct thread *thread)
 274 {
 275         const char *str;
 276
 277         down_read((struct rw_semaphore *)&thread->comm_lock);
 278         str = __thread__comm_str(thread);
 279         up_read((struct rw_semaphore *)&thread->comm_lock);
 280
 281         return str;
 282 }
 283
 284 /* CHECKME: it should probably better return the max comm len from its comm list */
 285 int thread__comm_len(struct thread *thread)
 286 {
 287         if (!thread->comm_len) {
 288                 const char *comm = thread__comm_str(thread);
 289                 if (!comm)
 290                         return 0;
 291                 thread->comm_len = strlen(comm);
 292         }
 293
 294         return thread->comm_len;
 295 }
 296
 297 size_t thread__fprintf(struct thread *thread, FILE *fp)
 298 {
 299         return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
 300                map_groups__fprintf(thread->mg, fp);
 301 }
 302
 303 int thread__insert_map(struct thread *thread, struct map *map)
 304 {
 305         int ret;
 306
 307         ret = unwind__prepare_access(thread, map, NULL);
 308         if (ret)
 309                 return ret;
 310
 311         map_groups__fixup_overlappings(thread->mg, map, stderr);
 312         map_groups__insert(thread->mg, map);
 313
 314         return 0;
 315 }
 316
 317 static int __thread__prepare_access(struct thread *thread)
 318 {
 319         bool initialized = false;
 320         int err = 0;
 321         struct maps *maps = &thread->mg->maps;
 322         struct map *map;
 323
 324         down_read(&maps->lock);
 325
 326         for (map = maps__first(maps); map; map = map__next(map)) {
 327                 err = unwind__prepare_access(thread, map, &initialized);
 328                 if (err || initialized)
 329                         break;
 330         }
 331
 332         up_read(&maps->lock);
 333
 334         return err;
 335 }
 336
 337 static int thread__prepare_access(struct thread *thread)
 338 {
 339         int err = 0;
 340
 341         if (symbol_conf.use_callchain)
 342                 err = __thread__prepare_access(thread);
 343
 344         return err;
 345 }
 346
 347 static int thread__clone_map_groups(struct thread *thread,
 348                                     struct thread *parent,
 349                                     bool do_maps_clone)
 350 {
 351         /* This is new thread, we share map groups for process. */
 352         if (thread->pid_ == parent->pid_)
 353                 return thread__prepare_access(thread);
 354
 355         if (thread->mg == parent->mg) {
 356                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 357                          thread->pid_, thread->tid, parent->pid_, parent->tid);
 358                 return 0;
 359         }
 360         /* But this one is new process, copy maps. */
 361         return do_maps_clone ? map_groups__clone(thread, parent->mg) : 0;
 362 }
 363
 364 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
 365 {
 366         if (parent->comm_set) {
 367                 const char *comm = thread__comm_str(parent);
 368                 int err;
 369                 if (!comm)
 370                         return -ENOMEM;
 371                 err = thread__set_comm(thread, comm, timestamp);
 372                 if (err)
 373                         return err;
 374         }
 375
 376         thread->ppid = parent->tid;
 377         return thread__clone_map_groups(thread, parent, do_maps_clone);
 378 }
 379
 380 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
 381                                         struct addr_location *al)
 382 {
 383         size_t i;
 384         const u8 cpumodes[] = {
 385                 PERF_RECORD_MISC_USER,
 386                 PERF_RECORD_MISC_KERNEL,
 387                 PERF_RECORD_MISC_GUEST_USER,
 388                 PERF_RECORD_MISC_GUEST_KERNEL
 389         };
 390
 391         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 392                 thread__find_symbol(thread, cpumodes[i], addr, al);
 393                 if (al->map)
 394                         break;
 395         }
 396 }
 397
 398 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 399 {
 400         if (thread->pid_ == thread->tid)
 401                 return thread__get(thread);
 402
 403         if (thread->pid_ == -1)
 404                 return NULL;
 405
 406         return machine__find_thread(machine, thread->pid_, thread->pid_);
 407 }
 408
 409 int thread__memcpy(struct thread *thread, struct machine *machine,
 410                    void *buf, u64 ip, int len, bool *is64bit)
 411 {
 412        u8 cpumode = PERF_RECORD_MISC_USER;
 413        struct addr_location al;
 414        long offset;
 415
 416        if (machine__kernel_ip(machine, ip))
 417                cpumode = PERF_RECORD_MISC_KERNEL;
 418
 419        if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso ||
 420            al.map->dso->data.status == DSO_DATA_STATUS_ERROR ||
 421            map__load(al.map) < 0)
 422                return -1;
 423
 424        offset = al.map->map_ip(al.map, ip);
 425        if (is64bit)
 426                *is64bit = al.map->dso->is_64_bit;
 427
 428        return dso__data_read_offset(al.map->dso, machine, offset, buf, len);
 429 }