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