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         }
  68
  69         return thread;
  70
  71 err_thread:
  72         free(thread);
  73         return NULL;
  74 }
  75
  76 void thread__delete(struct thread *thread)
  77 {
  78         struct namespaces *namespaces, *tmp_namespaces;
  79         struct comm *comm, *tmp_comm;
  80
  81         BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
  82
  83         thread_stack__free(thread);
  84
  85         if (thread->mg) {
  86                 map_groups__put(thread->mg);
  87                 thread->mg = NULL;
  88         }
  89         down_write(&thread->namespaces_lock);
  90         list_for_each_entry_safe(namespaces, tmp_namespaces,
  91                                  &thread->namespaces_list, list) {
  92                 list_del(&namespaces->list);
  93                 namespaces__free(namespaces);
  94         }
  95         up_write(&thread->namespaces_lock);
  96
  97         down_write(&thread->comm_lock);
  98         list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
  99                 list_del(&comm->list);
 100                 comm__free(comm);
 101         }
 102         up_write(&thread->comm_lock);
 103
 104         unwind__finish_access(thread);
 105         nsinfo__zput(thread->nsinfo);
 106
 107         exit_rwsem(&thread->namespaces_lock);
 108         exit_rwsem(&thread->comm_lock);
 109         free(thread);
 110 }
 111
 112 struct thread *thread__get(struct thread *thread)
 113 {
 114         if (thread)
 115                 refcount_inc(&thread->refcnt);
 116         return thread;
 117 }
 118
 119 void thread__put(struct thread *thread)
 120 {
 121         if (thread && refcount_dec_and_test(&thread->refcnt)) {
 122                 /*
 123                  * Remove it from the dead_threads list, as last reference
 124                  * is gone.
 125                  */
 126                 list_del_init(&thread->node);
 127                 thread__delete(thread);
 128         }
 129 }
 130
 131 struct namespaces *thread__namespaces(const struct thread *thread)
 132 {
 133         if (list_empty(&thread->namespaces_list))
 134                 return NULL;
 135
 136         return list_first_entry(&thread->namespaces_list, struct namespaces, list);
 137 }
 138
 139 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
 140                                     struct namespaces_event *event)
 141 {
 142         struct namespaces *new, *curr = thread__namespaces(thread);
 143
 144         new = namespaces__new(event);
 145         if (!new)
 146                 return -ENOMEM;
 147
 148         list_add(&new->list, &thread->namespaces_list);
 149
 150         if (timestamp && curr) {
 151                 /*
 152                  * setns syscall must have changed few or all the namespaces
 153                  * of this thread. Update end time for the namespaces
 154                  * previously used.
 155                  */
 156                 curr = list_next_entry(new, list);
 157                 curr->end_time = timestamp;
 158         }
 159
 160         return 0;
 161 }
 162
 163 int thread__set_namespaces(struct thread *thread, u64 timestamp,
 164                            struct namespaces_event *event)
 165 {
 166         int ret;
 167
 168         down_write(&thread->namespaces_lock);
 169         ret = __thread__set_namespaces(thread, timestamp, event);
 170         up_write(&thread->namespaces_lock);
 171         return ret;
 172 }
 173
 174 struct comm *thread__comm(const struct thread *thread)
 175 {
 176         if (list_empty(&thread->comm_list))
 177                 return NULL;
 178
 179         return list_first_entry(&thread->comm_list, struct comm, list);
 180 }
 181
 182 struct comm *thread__exec_comm(const struct thread *thread)
 183 {
 184         struct comm *comm, *last = NULL;
 185
 186         list_for_each_entry(comm, &thread->comm_list, list) {
 187                 if (comm->exec)
 188                         return comm;
 189                 last = comm;
 190         }
 191
 192         return last;
 193 }
 194
 195 static int ____thread__set_comm(struct thread *thread, const char *str,
 196                                 u64 timestamp, bool exec)
 197 {
 198         struct comm *new, *curr = thread__comm(thread);
 199
 200         /* Override the default :tid entry */
 201         if (!thread->comm_set) {
 202                 int err = comm__override(curr, str, timestamp, exec);
 203                 if (err)
 204                         return err;
 205         } else {
 206                 new = comm__new(str, timestamp, exec);
 207                 if (!new)
 208                         return -ENOMEM;
 209                 list_add(&new->list, &thread->comm_list);
 210
 211                 if (exec)
 212                         unwind__flush_access(thread);
 213         }
 214
 215         thread->comm_set = true;
 216
 217         return 0;
 218 }
 219
 220 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 221                        bool exec)
 222 {
 223         int ret;
 224
 225         down_write(&thread->comm_lock);
 226         ret = ____thread__set_comm(thread, str, timestamp, exec);
 227         up_write(&thread->comm_lock);
 228         return ret;
 229 }
 230
 231 int thread__set_comm_from_proc(struct thread *thread)
 232 {
 233         char path[64];
 234         char *comm = NULL;
 235         size_t sz;
 236         int err = -1;
 237
 238         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 239                        thread->pid_, thread->tid) >= (int)sizeof(path)) &&
 240             procfs__read_str(path, &comm, &sz) == 0) {
 241                 comm[sz - 1] = '\0';
 242                 err = thread__set_comm(thread, comm, 0);
 243         }
 244
 245         return err;
 246 }
 247
 248 static const char *__thread__comm_str(const struct thread *thread)
 249 {
 250         const struct comm *comm = thread__comm(thread);
 251
 252         if (!comm)
 253                 return NULL;
 254
 255         return comm__str(comm);
 256 }
 257
 258 const char *thread__comm_str(const struct thread *thread)
 259 {
 260         const char *str;
 261
 262         down_read((struct rw_semaphore *)&thread->comm_lock);
 263         str = __thread__comm_str(thread);
 264         up_read((struct rw_semaphore *)&thread->comm_lock);
 265
 266         return str;
 267 }
 268
 269 /* CHECKME: it should probably better return the max comm len from its comm list */
 270 int thread__comm_len(struct thread *thread)
 271 {
 272         if (!thread->comm_len) {
 273                 const char *comm = thread__comm_str(thread);
 274                 if (!comm)
 275                         return 0;
 276                 thread->comm_len = strlen(comm);
 277         }
 278
 279         return thread->comm_len;
 280 }
 281
 282 size_t thread__fprintf(struct thread *thread, FILE *fp)
 283 {
 284         return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
 285                map_groups__fprintf(thread->mg, fp);
 286 }
 287
 288 int thread__insert_map(struct thread *thread, struct map *map)
 289 {
 290         int ret;
 291
 292         ret = unwind__prepare_access(thread, map, NULL);
 293         if (ret)
 294                 return ret;
 295
 296         map_groups__fixup_overlappings(thread->mg, map, stderr);
 297         map_groups__insert(thread->mg, map);
 298
 299         return 0;
 300 }
 301
 302 static int __thread__prepare_access(struct thread *thread)
 303 {
 304         bool initialized = false;
 305         int err = 0;
 306         struct maps *maps = &thread->mg->maps;
 307         struct map *map;
 308
 309         down_read(&maps->lock);
 310
 311         for (map = maps__first(maps); map; map = map__next(map)) {
 312                 err = unwind__prepare_access(thread, map, &initialized);
 313                 if (err || initialized)
 314                         break;
 315         }
 316
 317         up_read(&maps->lock);
 318
 319         return err;
 320 }
 321
 322 static int thread__prepare_access(struct thread *thread)
 323 {
 324         int err = 0;
 325
 326         if (symbol_conf.use_callchain)
 327                 err = __thread__prepare_access(thread);
 328
 329         return err;
 330 }
 331
 332 static int thread__clone_map_groups(struct thread *thread,
 333                                     struct thread *parent)
 334 {
 335         /* This is new thread, we share map groups for process. */
 336         if (thread->pid_ == parent->pid_)
 337                 return thread__prepare_access(thread);
 338
 339         if (thread->mg == parent->mg) {
 340                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 341                          thread->pid_, thread->tid, parent->pid_, parent->tid);
 342                 return 0;
 343         }
 344
 345         /* But this one is new process, copy maps. */
 346         if (map_groups__clone(thread, parent->mg) < 0)
 347                 return -ENOMEM;
 348
 349         return 0;
 350 }
 351
 352 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 353 {
 354         if (parent->comm_set) {
 355                 const char *comm = thread__comm_str(parent);
 356                 int err;
 357                 if (!comm)
 358                         return -ENOMEM;
 359                 err = thread__set_comm(thread, comm, timestamp);
 360                 if (err)
 361                         return err;
 362         }
 363
 364         thread->ppid = parent->tid;
 365         return thread__clone_map_groups(thread, parent);
 366 }
 367
 368 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
 369                                         struct addr_location *al)
 370 {
 371         size_t i;
 372         const u8 cpumodes[] = {
 373                 PERF_RECORD_MISC_USER,
 374                 PERF_RECORD_MISC_KERNEL,
 375                 PERF_RECORD_MISC_GUEST_USER,
 376                 PERF_RECORD_MISC_GUEST_KERNEL
 377         };
 378
 379         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 380                 thread__find_symbol(thread, cpumodes[i], addr, al);
 381                 if (al->map)
 382                         break;
 383         }
 384 }
 385
 386 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 387 {
 388         if (thread->pid_ == thread->tid)
 389                 return thread__get(thread);
 390
 391         if (thread->pid_ == -1)
 392                 return NULL;
 393
 394         return machine__find_thread(machine, thread->pid_, thread->pid_);
 395 }