tools/perf/util/thread_map.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <dirent.h>
   3 #include <errno.h>
   4 #include <limits.h>
   5 #include <stdbool.h>
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <sys/types.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11 #include "string2.h"
  12 #include "strlist.h"
  13 #include <string.h>
  14 #include <api/fs/fs.h>
  15 #include <linux/string.h>
  16 #include <linux/zalloc.h>
  17 #include "asm/bug.h"
  18 #include "thread_map.h"
  19 #include "debug.h"
  20 #include "event.h"
  21
  22 /* Skip "." and ".." directories */
  23 static int filter(const struct dirent *dir)
  24 {
  25         if (dir->d_name[0] == '.')
  26                 return 0;
  27         else
  28                 return 1;
  29 }
  30
  31 static void thread_map__reset(struct thread_map *map, int start, int nr)
  32 {
  33         size_t size = (nr - start) * sizeof(map->map[0]);
  34
  35         memset(&map->map[start], 0, size);
  36         map->err_thread = -1;
  37 }
  38
  39 static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
  40 {
  41         size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
  42         int start = map ? map->nr : 0;
  43
  44         map = realloc(map, size);
  45         /*
  46          * We only realloc to add more items, let's reset new items.
  47          */
  48         if (map)
  49                 thread_map__reset(map, start, nr);
  50
  51         return map;
  52 }
  53
  54 #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
  55
  56 struct thread_map *thread_map__new_by_pid(pid_t pid)
  57 {
  58         struct thread_map *threads;
  59         char name[256];
  60         int items;
  61         struct dirent **namelist = NULL;
  62         int i;
  63
  64         sprintf(name, "/proc/%d/task", pid);
  65         items = scandir(name, &namelist, filter, NULL);
  66         if (items <= 0)
  67                 return NULL;
  68
  69         threads = thread_map__alloc(items);
  70         if (threads != NULL) {
  71                 for (i = 0; i < items; i++)
  72                         thread_map__set_pid(threads, i, atoi(namelist[i]->d_name));
  73                 threads->nr = items;
  74                 refcount_set(&threads->refcnt, 1);
  75         }
  76
  77         for (i=0; i<items; i++)
  78                 zfree(&namelist[i]);
  79         free(namelist);
  80
  81         return threads;
  82 }
  83
  84 struct thread_map *thread_map__new_by_tid(pid_t tid)
  85 {
  86         struct thread_map *threads = thread_map__alloc(1);
  87
  88         if (threads != NULL) {
  89                 thread_map__set_pid(threads, 0, tid);
  90                 threads->nr = 1;
  91                 refcount_set(&threads->refcnt, 1);
  92         }
  93
  94         return threads;
  95 }
  96
  97 static struct thread_map *__thread_map__new_all_cpus(uid_t uid)
  98 {
  99         DIR *proc;
 100         int max_threads = 32, items, i;
 101         char path[NAME_MAX + 1 + 6];
 102         struct dirent *dirent, **namelist = NULL;
 103         struct thread_map *threads = thread_map__alloc(max_threads);
 104
 105         if (threads == NULL)
 106                 goto out;
 107
 108         proc = opendir("/proc");
 109         if (proc == NULL)
 110                 goto out_free_threads;
 111
 112         threads->nr = 0;
 113         refcount_set(&threads->refcnt, 1);
 114
 115         while ((dirent = readdir(proc)) != NULL) {
 116                 char *end;
 117                 bool grow = false;
 118                 pid_t pid = strtol(dirent->d_name, &end, 10);
 119
 120                 if (*end) /* only interested in proper numerical dirents */
 121                         continue;
 122
 123                 snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
 124
 125                 if (uid != UINT_MAX) {
 126                         struct stat st;
 127
 128                         if (stat(path, &st) != 0 || st.st_uid != uid)
 129                                 continue;
 130                 }
 131
 132                 snprintf(path, sizeof(path), "/proc/%d/task", pid);
 133                 items = scandir(path, &namelist, filter, NULL);
 134                 if (items <= 0)
 135                         goto out_free_closedir;
 136
 137                 while (threads->nr + items >= max_threads) {
 138                         max_threads *= 2;
 139                         grow = true;
 140                 }
 141
 142                 if (grow) {
 143                         struct thread_map *tmp;
 144
 145                         tmp = thread_map__realloc(threads, max_threads);
 146                         if (tmp == NULL)
 147                                 goto out_free_namelist;
 148
 149                         threads = tmp;
 150                 }
 151
 152                 for (i = 0; i < items; i++) {
 153                         thread_map__set_pid(threads, threads->nr + i,
 154                                             atoi(namelist[i]->d_name));
 155                 }
 156
 157                 for (i = 0; i < items; i++)
 158                         zfree(&namelist[i]);
 159                 free(namelist);
 160
 161                 threads->nr += items;
 162         }
 163
 164 out_closedir:
 165         closedir(proc);
 166 out:
 167         return threads;
 168
 169 out_free_threads:
 170         free(threads);
 171         return NULL;
 172
 173 out_free_namelist:
 174         for (i = 0; i < items; i++)
 175                 zfree(&namelist[i]);
 176         free(namelist);
 177
 178 out_free_closedir:
 179         zfree(&threads);
 180         goto out_closedir;
 181 }
 182
 183 struct thread_map *thread_map__new_all_cpus(void)
 184 {
 185         return __thread_map__new_all_cpus(UINT_MAX);
 186 }
 187
 188 struct thread_map *thread_map__new_by_uid(uid_t uid)
 189 {
 190         return __thread_map__new_all_cpus(uid);
 191 }
 192
 193 struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
 194 {
 195         if (pid != -1)
 196                 return thread_map__new_by_pid(pid);
 197
 198         if (tid == -1 && uid != UINT_MAX)
 199                 return thread_map__new_by_uid(uid);
 200
 201         return thread_map__new_by_tid(tid);
 202 }
 203
 204 static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
 205 {
 206         struct thread_map *threads = NULL, *nt;
 207         char name[256];
 208         int items, total_tasks = 0;
 209         struct dirent **namelist = NULL;
 210         int i, j = 0;
 211         pid_t pid, prev_pid = INT_MAX;
 212         char *end_ptr;
 213         struct str_node *pos;
 214         struct strlist_config slist_config = { .dont_dupstr = true, };
 215         struct strlist *slist = strlist__new(pid_str, &slist_config);
 216
 217         if (!slist)
 218                 return NULL;
 219
 220         strlist__for_each_entry(pos, slist) {
 221                 pid = strtol(pos->s, &end_ptr, 10);
 222
 223                 if (pid == INT_MIN || pid == INT_MAX ||
 224                     (*end_ptr != '\0' && *end_ptr != ','))
 225                         goto out_free_threads;
 226
 227                 if (pid == prev_pid)
 228                         continue;
 229
 230                 sprintf(name, "/proc/%d/task", pid);
 231                 items = scandir(name, &namelist, filter, NULL);
 232                 if (items <= 0)
 233                         goto out_free_threads;
 234
 235                 total_tasks += items;
 236                 nt = thread_map__realloc(threads, total_tasks);
 237                 if (nt == NULL)
 238                         goto out_free_namelist;
 239
 240                 threads = nt;
 241
 242                 for (i = 0; i < items; i++) {
 243                         thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
 244                         zfree(&namelist[i]);
 245                 }
 246                 threads->nr = total_tasks;
 247                 free(namelist);
 248         }
 249
 250 out:
 251         strlist__delete(slist);
 252         if (threads)
 253                 refcount_set(&threads->refcnt, 1);
 254         return threads;
 255
 256 out_free_namelist:
 257         for (i = 0; i < items; i++)
 258                 zfree(&namelist[i]);
 259         free(namelist);
 260
 261 out_free_threads:
 262         zfree(&threads);
 263         goto out;
 264 }
 265
 266 struct thread_map *thread_map__new_dummy(void)
 267 {
 268         struct thread_map *threads = thread_map__alloc(1);
 269
 270         if (threads != NULL) {
 271                 thread_map__set_pid(threads, 0, -1);
 272                 threads->nr = 1;
 273                 refcount_set(&threads->refcnt, 1);
 274         }
 275         return threads;
 276 }
 277
 278 struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
 279 {
 280         struct thread_map *threads = NULL, *nt;
 281         int ntasks = 0;
 282         pid_t tid, prev_tid = INT_MAX;
 283         char *end_ptr;
 284         struct str_node *pos;
 285         struct strlist_config slist_config = { .dont_dupstr = true, };
 286         struct strlist *slist;
 287
 288         /* perf-stat expects threads to be generated even if tid not given */
 289         if (!tid_str)
 290                 return thread_map__new_dummy();
 291
 292         slist = strlist__new(tid_str, &slist_config);
 293         if (!slist)
 294                 return NULL;
 295
 296         strlist__for_each_entry(pos, slist) {
 297                 tid = strtol(pos->s, &end_ptr, 10);
 298
 299                 if (tid == INT_MIN || tid == INT_MAX ||
 300                     (*end_ptr != '\0' && *end_ptr != ','))
 301                         goto out_free_threads;
 302
 303                 if (tid == prev_tid)
 304                         continue;
 305
 306                 ntasks++;
 307                 nt = thread_map__realloc(threads, ntasks);
 308
 309                 if (nt == NULL)
 310                         goto out_free_threads;
 311
 312                 threads = nt;
 313                 thread_map__set_pid(threads, ntasks - 1, tid);
 314                 threads->nr = ntasks;
 315         }
 316 out:
 317         if (threads)
 318                 refcount_set(&threads->refcnt, 1);
 319         return threads;
 320
 321 out_free_threads:
 322         zfree(&threads);
 323         strlist__delete(slist);
 324         goto out;
 325 }
 326
 327 struct thread_map *thread_map__new_str(const char *pid, const char *tid,
 328                                        uid_t uid, bool all_threads)
 329 {
 330         if (pid)
 331                 return thread_map__new_by_pid_str(pid);
 332
 333         if (!tid && uid != UINT_MAX)
 334                 return thread_map__new_by_uid(uid);
 335
 336         if (all_threads)
 337                 return thread_map__new_all_cpus();
 338
 339         return thread_map__new_by_tid_str(tid);
 340 }
 341
 342 static void thread_map__delete(struct thread_map *threads)
 343 {
 344         if (threads) {
 345                 int i;
 346
 347                 WARN_ONCE(refcount_read(&threads->refcnt) != 0,
 348                           "thread map refcnt unbalanced\n");
 349                 for (i = 0; i < threads->nr; i++)
 350                         free(thread_map__comm(threads, i));
 351                 free(threads);
 352         }
 353 }
 354
 355 struct thread_map *thread_map__get(struct thread_map *map)
 356 {
 357         if (map)
 358                 refcount_inc(&map->refcnt);
 359         return map;
 360 }
 361
 362 void thread_map__put(struct thread_map *map)
 363 {
 364         if (map && refcount_dec_and_test(&map->refcnt))
 365                 thread_map__delete(map);
 366 }
 367
 368 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
 369 {
 370         int i;
 371         size_t printed = fprintf(fp, "%d thread%s: ",
 372                                  threads->nr, threads->nr > 1 ? "s" : "");
 373         for (i = 0; i < threads->nr; ++i)
 374                 printed += fprintf(fp, "%s%d", i ? ", " : "", thread_map__pid(threads, i));
 375
 376         return printed + fprintf(fp, "\n");
 377 }
 378
 379 static int get_comm(char **comm, pid_t pid)
 380 {
 381         char *path;
 382         size_t size;
 383         int err;
 384
 385         if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
 386                 return -ENOMEM;
 387
 388         err = filename__read_str(path, comm, &size);
 389         if (!err) {
 390                 /*
 391                  * We're reading 16 bytes, while filename__read_str
 392                  * allocates data per BUFSIZ bytes, so we can safely
 393                  * mark the end of the string.
 394                  */
 395                 (*comm)[size] = 0;
 396                 strim(*comm);
 397         }
 398
 399         free(path);
 400         return err;
 401 }
 402
 403 static void comm_init(struct thread_map *map, int i)
 404 {
 405         pid_t pid = thread_map__pid(map, i);
 406         char *comm = NULL;
 407
 408         /* dummy pid comm initialization */
 409         if (pid == -1) {
 410                 map->map[i].comm = strdup("dummy");
 411                 return;
 412         }
 413
 414         /*
 415          * The comm name is like extra bonus ;-),
 416          * so just warn if we fail for any reason.
 417          */
 418         if (get_comm(&comm, pid))
 419                 pr_warning("Couldn't resolve comm name for pid %d\n", pid);
 420
 421         map->map[i].comm = comm;
 422 }
 423
 424 void thread_map__read_comms(struct thread_map *threads)
 425 {
 426         int i;
 427
 428         for (i = 0; i < threads->nr; ++i)
 429                 comm_init(threads, i);
 430 }
 431
 432 static void thread_map__copy_event(struct thread_map *threads,
 433                                    struct thread_map_event *event)
 434 {
 435         unsigned i;
 436
 437         threads->nr = (int) event->nr;
 438
 439         for (i = 0; i < event->nr; i++) {
 440                 thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
 441                 threads->map[i].comm = strndup(event->entries[i].comm, 16);
 442         }
 443
 444         refcount_set(&threads->refcnt, 1);
 445 }
 446
 447 struct thread_map *thread_map__new_event(struct thread_map_event *event)
 448 {
 449         struct thread_map *threads;
 450
 451         threads = thread_map__alloc(event->nr);
 452         if (threads)
 453                 thread_map__copy_event(threads, event);
 454
 455         return threads;
 456 }
 457
 458 bool thread_map__has(struct thread_map *threads, pid_t pid)
 459 {
 460         int i;
 461
 462         for (i = 0; i < threads->nr; ++i) {
 463                 if (threads->map[i].pid == pid)
 464                         return true;
 465         }
 466
 467         return false;
 468 }
 469
 470 int thread_map__remove(struct thread_map *threads, int idx)
 471 {
 472         int i;
 473
 474         if (threads->nr < 1)
 475                 return -EINVAL;
 476
 477         if (idx >= threads->nr)
 478                 return -EINVAL;
 479
 480         /*
 481          * Free the 'idx' item and shift the rest up.
 482          */
 483         zfree(&threads->map[idx].comm);
 484
 485         for (i = idx; i < threads->nr - 1; i++)
 486                 threads->map[i] = threads->map[i + 1];
 487
 488         threads->nr--;
 489         return 0;
 490 }