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