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