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