tools/perf/util/thread_map.c

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