tools/perf/util/util.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "util.h"
   3 #include "debug.h"
   4 #include "event.h"
   5 #include <api/fs/fs.h>
   6 #include <sys/stat.h>
   7 #include <sys/utsname.h>
   8 #include <dirent.h>
   9 #include <fcntl.h>
  10 #include <inttypes.h>
  11 #include <signal.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <errno.h>
  16 #include <limits.h>
  17 #include <linux/capability.h>
  18 #include <linux/kernel.h>
  19 #include <linux/log2.h>
  20 #include <linux/time64.h>
  21 #include <linux/overflow.h>
  22 #include <unistd.h>
  23 #include "cap.h"
  24 #include "strlist.h"
  25 #include "string2.h"
  26
  27 /*
  28  * XXX We need to find a better place for these things...
  29  */
  30
  31 const char *input_name;
  32
  33 bool perf_singlethreaded = true;
  34
  35 void perf_set_singlethreaded(void)
  36 {
  37         perf_singlethreaded = true;
  38 }
  39
  40 void perf_set_multithreaded(void)
  41 {
  42         perf_singlethreaded = false;
  43 }
  44
  45 int sysctl_perf_event_max_stack = PERF_MAX_STACK_DEPTH;
  46 int sysctl_perf_event_max_contexts_per_stack = PERF_MAX_CONTEXTS_PER_STACK;
  47
  48 int sysctl__max_stack(void)
  49 {
  50         int value;
  51
  52         if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
  53                 sysctl_perf_event_max_stack = value;
  54
  55         if (sysctl__read_int("kernel/perf_event_max_contexts_per_stack", &value) == 0)
  56                 sysctl_perf_event_max_contexts_per_stack = value;
  57
  58         return sysctl_perf_event_max_stack;
  59 }
  60
  61 bool sysctl__nmi_watchdog_enabled(void)
  62 {
  63         static bool cached;
  64         static bool nmi_watchdog;
  65         int value;
  66
  67         if (cached)
  68                 return nmi_watchdog;
  69
  70         if (sysctl__read_int("kernel/nmi_watchdog", &value) < 0)
  71                 return false;
  72
  73         nmi_watchdog = (value > 0) ? true : false;
  74         cached = true;
  75
  76         return nmi_watchdog;
  77 }
  78
  79 bool test_attr__enabled;
  80
  81 bool exclude_GH_default;
  82
  83 bool perf_host  = true;
  84 bool perf_guest = false;
  85
  86 void event_attr_init(struct perf_event_attr *attr)
  87 {
  88         /* to capture ABI version */
  89         attr->size = sizeof(*attr);
  90
  91         if (!exclude_GH_default)
  92                 return;
  93
  94         if (!perf_host)
  95                 attr->exclude_host  = 1;
  96         if (!perf_guest)
  97                 attr->exclude_guest = 1;
  98 }
  99
 100 int mkdir_p(char *path, mode_t mode)
 101 {
 102         struct stat st;
 103         int err;
 104         char *d = path;
 105
 106         if (*d != '/')
 107                 return -1;
 108
 109         if (stat(path, &st) == 0)
 110                 return 0;
 111
 112         while (*++d == '/');
 113
 114         while ((d = strchr(d, '/'))) {
 115                 *d = '\0';
 116                 err = stat(path, &st) && mkdir(path, mode);
 117                 *d++ = '/';
 118                 if (err)
 119                         return -1;
 120                 while (*d == '/')
 121                         ++d;
 122         }
 123         return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
 124 }
 125
 126 static bool match_pat(char *file, const char **pat)
 127 {
 128         int i = 0;
 129
 130         if (!pat)
 131                 return true;
 132
 133         while (pat[i]) {
 134                 if (strglobmatch(file, pat[i]))
 135                         return true;
 136
 137                 i++;
 138         }
 139
 140         return false;
 141 }
 142
 143 /*
 144  * The depth specify how deep the removal will go.
 145  * 0       - will remove only files under the 'path' directory
 146  * 1 .. x  - will dive in x-level deep under the 'path' directory
 147  *
 148  * If specified the pat is array of string patterns ended with NULL,
 149  * which are checked upon every file/directory found. Only matching
 150  * ones are removed.
 151  *
 152  * The function returns:
 153  *    0 on success
 154  *   -1 on removal failure with errno set
 155  *   -2 on pattern failure
 156  */
 157 static int rm_rf_depth_pat(const char *path, int depth, const char **pat)
 158 {
 159         DIR *dir;
 160         int ret;
 161         struct dirent *d;
 162         char namebuf[PATH_MAX];
 163         struct stat statbuf;
 164
 165         /* Do not fail if there's no file. */
 166         ret = lstat(path, &statbuf);
 167         if (ret)
 168                 return 0;
 169
 170         /* Try to remove any file we get. */
 171         if (!(statbuf.st_mode & S_IFDIR))
 172                 return unlink(path);
 173
 174         /* We have directory in path. */
 175         dir = opendir(path);
 176         if (dir == NULL)
 177                 return -1;
 178
 179         while ((d = readdir(dir)) != NULL && !ret) {
 180
 181                 if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
 182                         continue;
 183
 184                 if (!match_pat(d->d_name, pat)) {
 185                         ret =  -2;
 186                         break;
 187                 }
 188
 189                 scnprintf(namebuf, sizeof(namebuf), "%s/%s",
 190                           path, d->d_name);
 191
 192                 /* We have to check symbolic link itself */
 193                 ret = lstat(namebuf, &statbuf);
 194                 if (ret < 0) {
 195                         pr_debug("stat failed: %s\n", namebuf);
 196                         break;
 197                 }
 198
 199                 if (S_ISDIR(statbuf.st_mode))
 200                         ret = depth ? rm_rf_depth_pat(namebuf, depth - 1, pat) : 0;
 201                 else
 202                         ret = unlink(namebuf);
 203         }
 204         closedir(dir);
 205
 206         if (ret < 0)
 207                 return ret;
 208
 209         return rmdir(path);
 210 }
 211
 212 static int rm_rf_a_kcore_dir(const char *path, const char *name)
 213 {
 214         char kcore_dir_path[PATH_MAX];
 215         const char *pat[] = {
 216                 "kcore",
 217                 "kallsyms",
 218                 "modules",
 219                 NULL,
 220         };
 221
 222         snprintf(kcore_dir_path, sizeof(kcore_dir_path), "%s/%s", path, name);
 223
 224         return rm_rf_depth_pat(kcore_dir_path, 0, pat);
 225 }
 226
 227 static bool kcore_dir_filter(const char *name __maybe_unused, struct dirent *d)
 228 {
 229         const char *pat[] = {
 230                 "kcore_dir",
 231                 "kcore_dir__[1-9]*",
 232                 NULL,
 233         };
 234
 235         return match_pat(d->d_name, pat);
 236 }
 237
 238 static int rm_rf_kcore_dir(const char *path)
 239 {
 240         struct strlist *kcore_dirs;
 241         struct str_node *nd;
 242         int ret;
 243
 244         kcore_dirs = lsdir(path, kcore_dir_filter);
 245
 246         if (!kcore_dirs)
 247                 return 0;
 248
 249         strlist__for_each_entry(nd, kcore_dirs) {
 250                 ret = rm_rf_a_kcore_dir(path, nd->s);
 251                 if (ret)
 252                         return ret;
 253         }
 254
 255         strlist__delete(kcore_dirs);
 256
 257         return 0;
 258 }
 259
 260 int rm_rf_perf_data(const char *path)
 261 {
 262         const char *pat[] = {
 263                 "data",
 264                 "data.*",
 265                 NULL,
 266         };
 267
 268         rm_rf_kcore_dir(path);
 269
 270         return rm_rf_depth_pat(path, 0, pat);
 271 }
 272
 273 int rm_rf(const char *path)
 274 {
 275         return rm_rf_depth_pat(path, INT_MAX, NULL);
 276 }
 277
 278 /* A filter which removes dot files */
 279 bool lsdir_no_dot_filter(const char *name __maybe_unused, struct dirent *d)
 280 {
 281         return d->d_name[0] != '.';
 282 }
 283
 284 /* lsdir reads a directory and store it in strlist */
 285 struct strlist *lsdir(const char *name,
 286                       bool (*filter)(const char *, struct dirent *))
 287 {
 288         struct strlist *list = NULL;
 289         DIR *dir;
 290         struct dirent *d;
 291
 292         dir = opendir(name);
 293         if (!dir)
 294                 return NULL;
 295
 296         list = strlist__new(NULL, NULL);
 297         if (!list) {
 298                 errno = ENOMEM;
 299                 goto out;
 300         }
 301
 302         while ((d = readdir(dir)) != NULL) {
 303                 if (!filter || filter(name, d))
 304                         strlist__add(list, d->d_name);
 305         }
 306
 307 out:
 308         closedir(dir);
 309         return list;
 310 }
 311
 312 size_t hex_width(u64 v)
 313 {
 314         size_t n = 1;
 315
 316         while ((v >>= 4))
 317                 ++n;
 318
 319         return n;
 320 }
 321
 322 int perf_event_paranoid(void)
 323 {
 324         int value;
 325
 326         if (sysctl__read_int("kernel/perf_event_paranoid", &value))
 327                 return INT_MAX;
 328
 329         return value;
 330 }
 331
 332 bool perf_event_paranoid_check(int max_level)
 333 {
 334         bool used_root;
 335
 336         if (perf_cap__capable(CAP_SYS_ADMIN, &used_root))
 337                 return true;
 338
 339         if (!used_root && perf_cap__capable(CAP_PERFMON, &used_root))
 340                 return true;
 341
 342         return perf_event_paranoid() <= max_level;
 343 }
 344
 345 int perf_tip(char **strp, const char *dirpath)
 346 {
 347         struct strlist *tips;
 348         struct str_node *node;
 349         struct strlist_config conf = {
 350                 .dirname = dirpath,
 351                 .file_only = true,
 352         };
 353         int ret = 0;
 354
 355         *strp = NULL;
 356         tips = strlist__new("tips.txt", &conf);
 357         if (tips == NULL)
 358                 return -errno;
 359
 360         if (strlist__nr_entries(tips) == 0)
 361                 goto out;
 362
 363         node = strlist__entry(tips, random() % strlist__nr_entries(tips));
 364         if (asprintf(strp, "Tip: %s", node->s) < 0)
 365                 ret = -ENOMEM;
 366
 367 out:
 368         strlist__delete(tips);
 369
 370         return ret;
 371 }
 372
 373 char *perf_exe(char *buf, int len)
 374 {
 375         int n = readlink("/proc/self/exe", buf, len);
 376         if (n > 0) {
 377                 buf[n] = 0;
 378                 return buf;
 379         }
 380         return strcpy(buf, "perf");
 381 }
 382
 383 void perf_debuginfod_setup(struct perf_debuginfod *di)
 384 {
 385         /*
 386          * By default '!di->set' we clear DEBUGINFOD_URLS, so debuginfod
 387          * processing is not triggered, otherwise we set it to 'di->urls'
 388          * value. If 'di->urls' is "system" we keep DEBUGINFOD_URLS value.
 389          */
 390         if (!di->set)
 391                 setenv("DEBUGINFOD_URLS", "", 1);
 392         else if (di->urls && strcmp(di->urls, "system"))
 393                 setenv("DEBUGINFOD_URLS", di->urls, 1);
 394
 395         pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS"));
 396
 397 #ifndef HAVE_DEBUGINFOD_SUPPORT
 398         if (di->set)
 399                 pr_warning("WARNING: debuginfod support requested, but perf is not built with it\n");
 400 #endif
 401 }
 402
 403 /*
 404  * Return a new filename prepended with task's root directory if it's in
 405  * a chroot.  Callers should free the returned string.
 406  */
 407 char *filename_with_chroot(int pid, const char *filename)
 408 {
 409         char buf[PATH_MAX];
 410         char proc_root[32];
 411         char *new_name = NULL;
 412         int ret;
 413
 414         scnprintf(proc_root, sizeof(proc_root), "/proc/%d/root", pid);
 415         ret = readlink(proc_root, buf, sizeof(buf) - 1);
 416         if (ret <= 0)
 417                 return NULL;
 418
 419         /* readlink(2) does not append a null byte to buf */
 420         buf[ret] = '\0';
 421
 422         if (!strcmp(buf, "/"))
 423                 return NULL;
 424
 425         if (strstr(buf, "(deleted)"))
 426                 return NULL;
 427
 428         if (asprintf(&new_name, "%s/%s", buf, filename) < 0)
 429                 return NULL;
 430
 431         return new_name;
 432 }
 433
 434 /*
 435  * Reallocate an array *arr of size *arr_sz so that it is big enough to contain
 436  * x elements of size msz, initializing new entries to *init_val or zero if
 437  * init_val is NULL
 438  */
 439 int do_realloc_array_as_needed(void **arr, size_t *arr_sz, size_t x, size_t msz, const void *init_val)
 440 {
 441         size_t new_sz = *arr_sz;
 442         void *new_arr;
 443         size_t i;
 444
 445         if (!new_sz)
 446                 new_sz = msz >= 64 ? 1 : roundup(64, msz); /* Start with at least 64 bytes */
 447         while (x >= new_sz) {
 448                 if (check_mul_overflow(new_sz, (size_t)2, &new_sz))
 449                         return -ENOMEM;
 450         }
 451         if (new_sz == *arr_sz)
 452                 return 0;
 453         new_arr = calloc(new_sz, msz);
 454         if (!new_arr)
 455                 return -ENOMEM;
 456         if (*arr_sz)
 457                 memcpy(new_arr, *arr, *arr_sz * msz);
 458         if (init_val) {
 459                 for (i = *arr_sz; i < new_sz; i++)
 460                         memcpy(new_arr + (i * msz), init_val, msz);
 461         }
 462         *arr = new_arr;
 463         *arr_sz = new_sz;
 464         return 0;
 465 }
 466
 467 #ifndef HAVE_SCHED_GETCPU_SUPPORT
 468 int sched_getcpu(void)
 469 {
 470 #ifdef __NR_getcpu
 471         unsigned int cpu;
 472         int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
 473
 474         if (!err)
 475                 return cpu;
 476 #else
 477         errno = ENOSYS;
 478 #endif
 479         return -1;
 480 }
 481 #endif
 482
 483 #ifndef HAVE_SCANDIRAT_SUPPORT
 484 int scandirat(int dirfd, const char *dirp,
 485               struct dirent ***namelist,
 486               int (*filter)(const struct dirent *),
 487               int (*compar)(const struct dirent **, const struct dirent **))
 488 {
 489         char path[PATH_MAX];
 490         int err, fd = openat(dirfd, dirp, O_PATH);
 491
 492         if (fd < 0)
 493                 return fd;
 494
 495         snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd);
 496         err = scandir(path, namelist, filter, compar);
 497         close(fd);
 498         return err;
 499 }
 500 #endif