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 = realloc(threads, (sizeof(*threads) +
 140                                                 max_threads * sizeof(pid_t)));
 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 *slist = strlist__new(false, pid_str);
 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 *slist;
 270
 271         /* perf-stat expects threads to be generated even if tid not given */
 272         if (!tid_str)
 273                 return thread_map__new_dummy();
 274
 275         slist = strlist__new(false, tid_str);
 276         if (!slist)
 277                 return NULL;
 278
 279         strlist__for_each(pos, slist) {
 280                 tid = strtol(pos->s, &end_ptr, 10);
 281
 282                 if (tid == INT_MIN || tid == INT_MAX ||
 283                     (*end_ptr != '\0' && *end_ptr != ','))
 284                         goto out_free_threads;
 285
 286                 if (tid == prev_tid)
 287                         continue;
 288
 289                 ntasks++;
 290                 nt = thread_map__realloc(threads, ntasks);
 291
 292                 if (nt == NULL)
 293                         goto out_free_threads;
 294
 295                 threads = nt;
 296                 thread_map__set_pid(threads, ntasks - 1, tid);
 297                 threads->nr = ntasks;
 298         }
 299 out:
 300         if (threads)
 301                 atomic_set(&threads->refcnt, 1);
 302         return threads;
 303
 304 out_free_threads:
 305         zfree(&threads);
 306         goto out;
 307 }
 308
 309 struct thread_map *thread_map__new_str(const char *pid, const char *tid,
 310                                        uid_t uid)
 311 {
 312         if (pid)
 313                 return thread_map__new_by_pid_str(pid);
 314
 315         if (!tid && uid != UINT_MAX)
 316                 return thread_map__new_by_uid(uid);
 317
 318         return thread_map__new_by_tid_str(tid);
 319 }
 320
 321 static void thread_map__delete(struct thread_map *threads)
 322 {
 323         if (threads) {
 324                 int i;
 325
 326                 WARN_ONCE(atomic_read(&threads->refcnt) != 0,
 327                           "thread map refcnt unbalanced\n");
 328                 for (i = 0; i < threads->nr; i++)
 329                         free(thread_map__comm(threads, i));
 330                 free(threads);
 331         }
 332 }
 333
 334 struct thread_map *thread_map__get(struct thread_map *map)
 335 {
 336         if (map)
 337                 atomic_inc(&map->refcnt);
 338         return map;
 339 }
 340
 341 void thread_map__put(struct thread_map *map)
 342 {
 343         if (map && atomic_dec_and_test(&map->refcnt))
 344                 thread_map__delete(map);
 345 }
 346
 347 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
 348 {
 349         int i;
 350         size_t printed = fprintf(fp, "%d thread%s: ",
 351                                  threads->nr, threads->nr > 1 ? "s" : "");
 352         for (i = 0; i < threads->nr; ++i)
 353                 printed += fprintf(fp, "%s%d", i ? ", " : "", thread_map__pid(threads, i));
 354
 355         return printed + fprintf(fp, "\n");
 356 }
 357
 358 static int get_comm(char **comm, pid_t pid)
 359 {
 360         char *path;
 361         size_t size;
 362         int err;
 363
 364         if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
 365                 return -ENOMEM;
 366
 367         err = filename__read_str(path, comm, &size);
 368         if (!err) {
 369                 /*
 370                  * We're reading 16 bytes, while filename__read_str
 371                  * allocates data per BUFSIZ bytes, so we can safely
 372                  * mark the end of the string.
 373                  */
 374                 (*comm)[size] = 0;
 375                 rtrim(*comm);
 376         }
 377
 378         free(path);
 379         return err;
 380 }
 381
 382 static void comm_init(struct thread_map *map, int i)
 383 {
 384         pid_t pid = thread_map__pid(map, i);
 385         char *comm = NULL;
 386
 387         /* dummy pid comm initialization */
 388         if (pid == -1) {
 389                 map->map[i].comm = strdup("dummy");
 390                 return;
 391         }
 392
 393         /*
 394          * The comm name is like extra bonus ;-),
 395          * so just warn if we fail for any reason.
 396          */
 397         if (get_comm(&comm, pid))
 398                 pr_warning("Couldn't resolve comm name for pid %d\n", pid);
 399
 400         map->map[i].comm = comm;
 401 }
 402
 403 void thread_map__read_comms(struct thread_map *threads)
 404 {
 405         int i;
 406
 407         for (i = 0; i < threads->nr; ++i)
 408                 comm_init(threads, i);
 409 }