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                         goto out_free_closedir;
 114
 115                 while (threads->nr + items >= max_threads) {
 116                         max_threads *= 2;
 117                         grow = true;
 118                 }
 119
 120                 if (grow) {
 121                         struct perf_thread_map *tmp;
 122
 123                         tmp = perf_thread_map__realloc(threads, max_threads);
 124                         if (tmp == NULL)
 125                                 goto out_free_namelist;
 126
 127                         threads = tmp;
 128                 }
 129
 130                 for (i = 0; i < items; i++) {
 131                         perf_thread_map__set_pid(threads, threads->nr + i,
 132                                                     atoi(namelist[i]->d_name));
 133                 }
 134
 135                 for (i = 0; i < items; i++)
 136                         zfree(&namelist[i]);
 137                 free(namelist);
 138
 139                 threads->nr += items;
 140         }
 141
 142 out_closedir:
 143         closedir(proc);
 144 out:
 145         return threads;
 146
 147 out_free_threads:
 148         free(threads);
 149         return NULL;
 150
 151 out_free_namelist:
 152         for (i = 0; i < items; i++)
 153                 zfree(&namelist[i]);
 154         free(namelist);
 155
 156 out_free_closedir:
 157         zfree(&threads);
 158         goto out_closedir;
 159 }
 160
 161 struct perf_thread_map *thread_map__new_all_cpus(void)
 162 {
 163         return __thread_map__new_all_cpus(UINT_MAX);
 164 }
 165
 166 struct perf_thread_map *thread_map__new_by_uid(uid_t uid)
 167 {
 168         return __thread_map__new_all_cpus(uid);
 169 }
 170
 171 struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
 172 {
 173         if (pid != -1)
 174                 return thread_map__new_by_pid(pid);
 175
 176         if (tid == -1 && uid != UINT_MAX)
 177                 return thread_map__new_by_uid(uid);
 178
 179         return thread_map__new_by_tid(tid);
 180 }
 181
 182 static struct perf_thread_map *thread_map__new_by_pid_str(const char *pid_str)
 183 {
 184         struct perf_thread_map *threads = NULL, *nt;
 185         char name[256];
 186         int items, total_tasks = 0;
 187         struct dirent **namelist = NULL;
 188         int i, j = 0;
 189         pid_t pid, prev_pid = INT_MAX;
 190         char *end_ptr;
 191         struct str_node *pos;
 192         struct strlist_config slist_config = { .dont_dupstr = true, };
 193         struct strlist *slist = strlist__new(pid_str, &slist_config);
 194
 195         if (!slist)
 196                 return NULL;
 197
 198         strlist__for_each_entry(pos, slist) {
 199                 pid = strtol(pos->s, &end_ptr, 10);
 200
 201                 if (pid == INT_MIN || pid == INT_MAX ||
 202                     (*end_ptr != '\0' && *end_ptr != ','))
 203                         goto out_free_threads;
 204
 205                 if (pid == prev_pid)
 206                         continue;
 207
 208                 sprintf(name, "/proc/%d/task", pid);
 209                 items = scandir(name, &namelist, filter, NULL);
 210                 if (items <= 0)
 211                         goto out_free_threads;
 212
 213                 total_tasks += items;
 214                 nt = perf_thread_map__realloc(threads, total_tasks);
 215                 if (nt == NULL)
 216                         goto out_free_namelist;
 217
 218                 threads = nt;
 219
 220                 for (i = 0; i < items; i++) {
 221                         perf_thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
 222                         zfree(&namelist[i]);
 223                 }
 224                 threads->nr = total_tasks;
 225                 free(namelist);
 226         }
 227
 228 out:
 229         strlist__delete(slist);
 230         if (threads)
 231                 refcount_set(&threads->refcnt, 1);
 232         return threads;
 233
 234 out_free_namelist:
 235         for (i = 0; i < items; i++)
 236                 zfree(&namelist[i]);
 237         free(namelist);
 238
 239 out_free_threads:
 240         zfree(&threads);
 241         goto out;
 242 }
 243
 244 struct perf_thread_map *thread_map__new_by_tid_str(const char *tid_str)
 245 {
 246         struct perf_thread_map *threads = NULL, *nt;
 247         int ntasks = 0;
 248         pid_t tid, prev_tid = INT_MAX;
 249         char *end_ptr;
 250         struct str_node *pos;
 251         struct strlist_config slist_config = { .dont_dupstr = true, };
 252         struct strlist *slist;
 253
 254         /* perf-stat expects threads to be generated even if tid not given */
 255         if (!tid_str)
 256                 return perf_thread_map__new_dummy();
 257
 258         slist = strlist__new(tid_str, &slist_config);
 259         if (!slist)
 260                 return NULL;
 261
 262         strlist__for_each_entry(pos, slist) {
 263                 tid = strtol(pos->s, &end_ptr, 10);
 264
 265                 if (tid == INT_MIN || tid == INT_MAX ||
 266                     (*end_ptr != '\0' && *end_ptr != ','))
 267                         goto out_free_threads;
 268
 269                 if (tid == prev_tid)
 270                         continue;
 271
 272                 ntasks++;
 273                 nt = perf_thread_map__realloc(threads, ntasks);
 274
 275                 if (nt == NULL)
 276                         goto out_free_threads;
 277
 278                 threads = nt;
 279                 perf_thread_map__set_pid(threads, ntasks - 1, tid);
 280                 threads->nr = ntasks;
 281         }
 282 out:
 283         if (threads)
 284                 refcount_set(&threads->refcnt, 1);
 285         return threads;
 286
 287 out_free_threads:
 288         zfree(&threads);
 289         strlist__delete(slist);
 290         goto out;
 291 }
 292
 293 struct perf_thread_map *thread_map__new_str(const char *pid, const char *tid,
 294                                        uid_t uid, bool all_threads)
 295 {
 296         if (pid)
 297                 return thread_map__new_by_pid_str(pid);
 298
 299         if (!tid && uid != UINT_MAX)
 300                 return thread_map__new_by_uid(uid);
 301
 302         if (all_threads)
 303                 return thread_map__new_all_cpus();
 304
 305         return thread_map__new_by_tid_str(tid);
 306 }
 307
 308 size_t thread_map__fprintf(struct perf_thread_map *threads, FILE *fp)
 309 {
 310         int i;
 311         size_t printed = fprintf(fp, "%d thread%s: ",
 312                                  threads->nr, threads->nr > 1 ? "s" : "");
 313         for (i = 0; i < threads->nr; ++i)
 314                 printed += fprintf(fp, "%s%d", i ? ", " : "", perf_thread_map__pid(threads, i));
 315
 316         return printed + fprintf(fp, "\n");
 317 }
 318
 319 static int get_comm(char **comm, pid_t pid)
 320 {
 321         char *path;
 322         size_t size;
 323         int err;
 324
 325         if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
 326                 return -ENOMEM;
 327
 328         err = filename__read_str(path, comm, &size);
 329         if (!err) {
 330                 /*
 331                  * We're reading 16 bytes, while filename__read_str
 332                  * allocates data per BUFSIZ bytes, so we can safely
 333                  * mark the end of the string.
 334                  */
 335                 (*comm)[size] = 0;
 336                 strim(*comm);
 337         }
 338
 339         free(path);
 340         return err;
 341 }
 342
 343 static void comm_init(struct perf_thread_map *map, int i)
 344 {
 345         pid_t pid = perf_thread_map__pid(map, i);
 346         char *comm = NULL;
 347
 348         /* dummy pid comm initialization */
 349         if (pid == -1) {
 350                 map->map[i].comm = strdup("dummy");
 351                 return;
 352         }
 353
 354         /*
 355          * The comm name is like extra bonus ;-),
 356          * so just warn if we fail for any reason.
 357          */
 358         if (get_comm(&comm, pid))
 359                 pr_warning("Couldn't resolve comm name for pid %d\n", pid);
 360
 361         map->map[i].comm = comm;
 362 }
 363
 364 void thread_map__read_comms(struct perf_thread_map *threads)
 365 {
 366         int i;
 367
 368         for (i = 0; i < threads->nr; ++i)
 369                 comm_init(threads, i);
 370 }
 371
 372 static void thread_map__copy_event(struct perf_thread_map *threads,
 373                                    struct perf_record_thread_map *event)
 374 {
 375         unsigned i;
 376
 377         threads->nr = (int) event->nr;
 378
 379         for (i = 0; i < event->nr; i++) {
 380                 perf_thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
 381                 threads->map[i].comm = strndup(event->entries[i].comm, 16);
 382         }
 383
 384         refcount_set(&threads->refcnt, 1);
 385 }
 386
 387 struct perf_thread_map *thread_map__new_event(struct perf_record_thread_map *event)
 388 {
 389         struct perf_thread_map *threads;
 390
 391         threads = thread_map__alloc(event->nr);
 392         if (threads)
 393                 thread_map__copy_event(threads, event);
 394
 395         return threads;
 396 }
 397
 398 bool thread_map__has(struct perf_thread_map *threads, pid_t pid)
 399 {
 400         int i;
 401
 402         for (i = 0; i < threads->nr; ++i) {
 403                 if (threads->map[i].pid == pid)
 404                         return true;
 405         }
 406
 407         return false;
 408 }
 409
 410 int thread_map__remove(struct perf_thread_map *threads, int idx)
 411 {
 412         int i;
 413
 414         if (threads->nr < 1)
 415                 return -EINVAL;
 416
 417         if (idx >= threads->nr)
 418                 return -EINVAL;
 419
 420         /*
 421          * Free the 'idx' item and shift the rest up.
 422          */
 423         zfree(&threads->map[idx].comm);
 424
 425         for (i = idx; i < threads->nr - 1; i++)
 426                 threads->map[i] = threads->map[i + 1];
 427
 428         threads->nr--;
 429         return 0;
 430 }