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