src/basic/process-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <ctype.h>
  21 #include <errno.h>
  22 #include <limits.h>
  23 #include <linux/oom.h>
  24 #include <sched.h>
  25 #include <signal.h>
  26 #include <stdbool.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/personality.h>
  31 #include <sys/prctl.h>
  32 #include <sys/types.h>
  33 #include <sys/wait.h>
  34 #include <syslog.h>
  35 #include <unistd.h>
  36 #ifdef HAVE_VALGRIND_VALGRIND_H
  37 #include <valgrind/valgrind.h>
  38 #endif
  39
  40 #include "alloc-util.h"
  41 #include "architecture.h"
  42 #include "escape.h"
  43 #include "fd-util.h"
  44 #include "fileio.h"
  45 #include "fs-util.h"
  46 #include "ioprio.h"
  47 #include "log.h"
  48 #include "macro.h"
  49 #include "missing.h"
  50 #include "process-util.h"
  51 #include "signal-util.h"
  52 #include "stat-util.h"
  53 #include "string-table.h"
  54 #include "string-util.h"
  55 #include "user-util.h"
  56 #include "util.h"
  57
  58 int get_process_state(pid_t pid) {
  59         const char *p;
  60         char state;
  61         int r;
  62         _cleanup_free_ char *line = NULL;
  63
  64         assert(pid >= 0);
  65
  66         p = procfs_file_alloca(pid, "stat");
  67
  68         r = read_one_line_file(p, &line);
  69         if (r == -ENOENT)
  70                 return -ESRCH;
  71         if (r < 0)
  72                 return r;
  73
  74         p = strrchr(line, ')');
  75         if (!p)
  76                 return -EIO;
  77
  78         p++;
  79
  80         if (sscanf(p, " %c", &state) != 1)
  81                 return -EIO;
  82
  83         return (unsigned char) state;
  84 }
  85
  86 int get_process_comm(pid_t pid, char **name) {
  87         const char *p;
  88         int r;
  89
  90         assert(name);
  91         assert(pid >= 0);
  92
  93         p = procfs_file_alloca(pid, "comm");
  94
  95         r = read_one_line_file(p, name);
  96         if (r == -ENOENT)
  97                 return -ESRCH;
  98
  99         return r;
 100 }
 101
 102 int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) {
 103         _cleanup_fclose_ FILE *f = NULL;
 104         char *r = NULL, *k;
 105         const char *p;
 106         int c;
 107
 108         assert(line);
 109         assert(pid >= 0);
 110
 111         p = procfs_file_alloca(pid, "cmdline");
 112
 113         f = fopen(p, "re");
 114         if (!f) {
 115                 if (errno == ENOENT)
 116                         return -ESRCH;
 117                 return -errno;
 118         }
 119
 120         if (max_length == 0) {
 121                 size_t len = 0, allocated = 0;
 122
 123                 while ((c = getc(f)) != EOF) {
 124
 125                         if (!GREEDY_REALLOC(r, allocated, len+2)) {
 126                                 free(r);
 127                                 return -ENOMEM;
 128                         }
 129
 130                         r[len++] = isprint(c) ? c : ' ';
 131                 }
 132
 133                 if (len > 0)
 134                         r[len-1] = 0;
 135
 136         } else {
 137                 bool space = false;
 138                 size_t left;
 139
 140                 r = new(char, max_length);
 141                 if (!r)
 142                         return -ENOMEM;
 143
 144                 k = r;
 145                 left = max_length;
 146                 while ((c = getc(f)) != EOF) {
 147
 148                         if (isprint(c)) {
 149                                 if (space) {
 150                                         if (left <= 4)
 151                                                 break;
 152
 153                                         *(k++) = ' ';
 154                                         left--;
 155                                         space = false;
 156                                 }
 157
 158                                 if (left <= 4)
 159                                         break;
 160
 161                                 *(k++) = (char) c;
 162                                 left--;
 163                         }  else
 164                                 space = true;
 165                 }
 166
 167                 if (left <= 4) {
 168                         size_t n = MIN(left-1, 3U);
 169                         memcpy(k, "...", n);
 170                         k[n] = 0;
 171                 } else
 172                         *k = 0;
 173         }
 174
 175         /* Kernel threads have no argv[] */
 176         if (isempty(r)) {
 177                 _cleanup_free_ char *t = NULL;
 178                 int h;
 179
 180                 free(r);
 181
 182                 if (!comm_fallback)
 183                         return -ENOENT;
 184
 185                 h = get_process_comm(pid, &t);
 186                 if (h < 0)
 187                         return h;
 188
 189                 r = strjoin("[", t, "]", NULL);
 190                 if (!r)
 191                         return -ENOMEM;
 192         }
 193
 194         *line = r;
 195         return 0;
 196 }
 197
 198 void rename_process(const char name[8]) {
 199         assert(name);
 200
 201         /* This is a like a poor man's setproctitle(). It changes the
 202          * comm field, argv[0], and also the glibc's internally used
 203          * name of the process. For the first one a limit of 16 chars
 204          * applies, to the second one usually one of 10 (i.e. length
 205          * of "/sbin/init"), to the third one one of 7 (i.e. length of
 206          * "systemd"). If you pass a longer string it will be
 207          * truncated */
 208
 209         (void) prctl(PR_SET_NAME, name);
 210
 211         if (program_invocation_name)
 212                 strncpy(program_invocation_name, name, strlen(program_invocation_name));
 213
 214         if (saved_argc > 0) {
 215                 int i;
 216
 217                 if (saved_argv[0])
 218                         strncpy(saved_argv[0], name, strlen(saved_argv[0]));
 219
 220                 for (i = 1; i < saved_argc; i++) {
 221                         if (!saved_argv[i])
 222                                 break;
 223
 224                         memzero(saved_argv[i], strlen(saved_argv[i]));
 225                 }
 226         }
 227 }
 228
 229 int is_kernel_thread(pid_t pid) {
 230         const char *p;
 231         size_t count;
 232         char c;
 233         bool eof;
 234         FILE *f;
 235
 236         if (pid == 0 || pid == 1) /* pid 1, and we ourselves certainly aren't a kernel thread */
 237                 return 0;
 238
 239         assert(pid > 1);
 240
 241         p = procfs_file_alloca(pid, "cmdline");
 242         f = fopen(p, "re");
 243         if (!f) {
 244                 if (errno == ENOENT)
 245                         return -ESRCH;
 246                 return -errno;
 247         }
 248
 249         count = fread(&c, 1, 1, f);
 250         eof = feof(f);
 251         fclose(f);
 252
 253         /* Kernel threads have an empty cmdline */
 254
 255         if (count <= 0)
 256                 return eof ? 1 : -errno;
 257
 258         return 0;
 259 }
 260
 261 int get_process_capeff(pid_t pid, char **capeff) {
 262         const char *p;
 263         int r;
 264
 265         assert(capeff);
 266         assert(pid >= 0);
 267
 268         p = procfs_file_alloca(pid, "status");
 269
 270         r = get_proc_field(p, "CapEff", WHITESPACE, capeff);
 271         if (r == -ENOENT)
 272                 return -ESRCH;
 273
 274         return r;
 275 }
 276
 277 static int get_process_link_contents(const char *proc_file, char **name) {
 278         int r;
 279
 280         assert(proc_file);
 281         assert(name);
 282
 283         r = readlink_malloc(proc_file, name);
 284         if (r == -ENOENT)
 285                 return -ESRCH;
 286         if (r < 0)
 287                 return r;
 288
 289         return 0;
 290 }
 291
 292 int get_process_exe(pid_t pid, char **name) {
 293         const char *p;
 294         char *d;
 295         int r;
 296
 297         assert(pid >= 0);
 298
 299         p = procfs_file_alloca(pid, "exe");
 300         r = get_process_link_contents(p, name);
 301         if (r < 0)
 302                 return r;
 303
 304         d = endswith(*name, " (deleted)");
 305         if (d)
 306                 *d = '\0';
 307
 308         return 0;
 309 }
 310
 311 static int get_process_id(pid_t pid, const char *field, uid_t *uid) {
 312         _cleanup_fclose_ FILE *f = NULL;
 313         char line[LINE_MAX];
 314         const char *p;
 315
 316         assert(field);
 317         assert(uid);
 318
 319         if (pid == 0)
 320                 return getuid();
 321
 322         p = procfs_file_alloca(pid, "status");
 323         f = fopen(p, "re");
 324         if (!f) {
 325                 if (errno == ENOENT)
 326                         return -ESRCH;
 327                 return -errno;
 328         }
 329
 330         FOREACH_LINE(line, f, return -errno) {
 331                 char *l;
 332
 333                 l = strstrip(line);
 334
 335                 if (startswith(l, field)) {
 336                         l += strlen(field);
 337                         l += strspn(l, WHITESPACE);
 338
 339                         l[strcspn(l, WHITESPACE)] = 0;
 340
 341                         return parse_uid(l, uid);
 342                 }
 343         }
 344
 345         return -EIO;
 346 }
 347
 348 int get_process_uid(pid_t pid, uid_t *uid) {
 349         return get_process_id(pid, "Uid:", uid);
 350 }
 351
 352 int get_process_gid(pid_t pid, gid_t *gid) {
 353         assert_cc(sizeof(uid_t) == sizeof(gid_t));
 354         return get_process_id(pid, "Gid:", gid);
 355 }
 356
 357 int get_process_cwd(pid_t pid, char **cwd) {
 358         const char *p;
 359
 360         assert(pid >= 0);
 361
 362         p = procfs_file_alloca(pid, "cwd");
 363
 364         return get_process_link_contents(p, cwd);
 365 }
 366
 367 int get_process_root(pid_t pid, char **root) {
 368         const char *p;
 369
 370         assert(pid >= 0);
 371
 372         p = procfs_file_alloca(pid, "root");
 373
 374         return get_process_link_contents(p, root);
 375 }
 376
 377 int get_process_environ(pid_t pid, char **env) {
 378         _cleanup_fclose_ FILE *f = NULL;
 379         _cleanup_free_ char *outcome = NULL;
 380         int c;
 381         const char *p;
 382         size_t allocated = 0, sz = 0;
 383
 384         assert(pid >= 0);
 385         assert(env);
 386
 387         p = procfs_file_alloca(pid, "environ");
 388
 389         f = fopen(p, "re");
 390         if (!f) {
 391                 if (errno == ENOENT)
 392                         return -ESRCH;
 393                 return -errno;
 394         }
 395
 396         while ((c = fgetc(f)) != EOF) {
 397                 if (!GREEDY_REALLOC(outcome, allocated, sz + 5))
 398                         return -ENOMEM;
 399
 400                 if (c == '\0')
 401                         outcome[sz++] = '\n';
 402                 else
 403                         sz += cescape_char(c, outcome + sz);
 404         }
 405
 406         if (!outcome) {
 407                 outcome = strdup("");
 408                 if (!outcome)
 409                         return -ENOMEM;
 410         } else
 411                 outcome[sz] = '\0';
 412
 413         *env = outcome;
 414         outcome = NULL;
 415
 416         return 0;
 417 }
 418
 419 int get_process_ppid(pid_t pid, pid_t *_ppid) {
 420         int r;
 421         _cleanup_free_ char *line = NULL;
 422         long unsigned ppid;
 423         const char *p;
 424
 425         assert(pid >= 0);
 426         assert(_ppid);
 427
 428         if (pid == 0) {
 429                 *_ppid = getppid();
 430                 return 0;
 431         }
 432
 433         p = procfs_file_alloca(pid, "stat");
 434         r = read_one_line_file(p, &line);
 435         if (r == -ENOENT)
 436                 return -ESRCH;
 437         if (r < 0)
 438                 return r;
 439
 440         /* Let's skip the pid and comm fields. The latter is enclosed
 441          * in () but does not escape any () in its value, so let's
 442          * skip over it manually */
 443
 444         p = strrchr(line, ')');
 445         if (!p)
 446                 return -EIO;
 447
 448         p++;
 449
 450         if (sscanf(p, " "
 451                    "%*c "  /* state */
 452                    "%lu ", /* ppid */
 453                    &ppid) != 1)
 454                 return -EIO;
 455
 456         if ((long unsigned) (pid_t) ppid != ppid)
 457                 return -ERANGE;
 458
 459         *_ppid = (pid_t) ppid;
 460
 461         return 0;
 462 }
 463
 464 int wait_for_terminate(pid_t pid, siginfo_t *status) {
 465         siginfo_t dummy;
 466
 467         assert(pid >= 1);
 468
 469         if (!status)
 470                 status = &dummy;
 471
 472         for (;;) {
 473                 zero(*status);
 474
 475                 if (waitid(P_PID, pid, status, WEXITED) < 0) {
 476
 477                         if (errno == EINTR)
 478                                 continue;
 479
 480                         return -errno;
 481                 }
 482
 483                 return 0;
 484         }
 485 }
 486
 487 /*
 488  * Return values:
 489  * < 0 : wait_for_terminate() failed to get the state of the
 490  *       process, the process was terminated by a signal, or
 491  *       failed for an unknown reason.
 492  * >=0 : The process terminated normally, and its exit code is
 493  *       returned.
 494  *
 495  * That is, success is indicated by a return value of zero, and an
 496  * error is indicated by a non-zero value.
 497  *
 498  * A warning is emitted if the process terminates abnormally,
 499  * and also if it returns non-zero unless check_exit_code is true.
 500  */
 501 int wait_for_terminate_and_warn(const char *name, pid_t pid, bool check_exit_code) {
 502         int r;
 503         siginfo_t status;
 504
 505         assert(name);
 506         assert(pid > 1);
 507
 508         r = wait_for_terminate(pid, &status);
 509         if (r < 0)
 510                 return log_warning_errno(r, "Failed to wait for %s: %m", name);
 511
 512         if (status.si_code == CLD_EXITED) {
 513                 if (status.si_status != 0)
 514                         log_full(check_exit_code ? LOG_WARNING : LOG_DEBUG,
 515                                  "%s failed with error code %i.", name, status.si_status);
 516                 else
 517                         log_debug("%s succeeded.", name);
 518
 519                 return status.si_status;
 520         } else if (status.si_code == CLD_KILLED ||
 521                    status.si_code == CLD_DUMPED) {
 522
 523                 log_warning("%s terminated by signal %s.", name, signal_to_string(status.si_status));
 524                 return -EPROTO;
 525         }
 526
 527         log_warning("%s failed due to unknown reason.", name);
 528         return -EPROTO;
 529 }
 530
 531 void sigkill_wait(pid_t pid) {
 532         assert(pid > 1);
 533
 534         if (kill(pid, SIGKILL) > 0)
 535                 (void) wait_for_terminate(pid, NULL);
 536 }
 537
 538 void sigkill_waitp(pid_t *pid) {
 539         if (!pid)
 540                 return;
 541         if (*pid <= 1)
 542                 return;
 543
 544         sigkill_wait(*pid);
 545 }
 546
 547 int kill_and_sigcont(pid_t pid, int sig) {
 548         int r;
 549
 550         r = kill(pid, sig) < 0 ? -errno : 0;
 551
 552         if (r >= 0)
 553                 kill(pid, SIGCONT);
 554
 555         return r;
 556 }
 557
 558 int getenv_for_pid(pid_t pid, const char *field, char **_value) {
 559         _cleanup_fclose_ FILE *f = NULL;
 560         char *value = NULL;
 561         int r;
 562         bool done = false;
 563         size_t l;
 564         const char *path;
 565
 566         assert(pid >= 0);
 567         assert(field);
 568         assert(_value);
 569
 570         path = procfs_file_alloca(pid, "environ");
 571
 572         f = fopen(path, "re");
 573         if (!f) {
 574                 if (errno == ENOENT)
 575                         return -ESRCH;
 576                 return -errno;
 577         }
 578
 579         l = strlen(field);
 580         r = 0;
 581
 582         do {
 583                 char line[LINE_MAX];
 584                 unsigned i;
 585
 586                 for (i = 0; i < sizeof(line)-1; i++) {
 587                         int c;
 588
 589                         c = getc(f);
 590                         if (_unlikely_(c == EOF)) {
 591                                 done = true;
 592                                 break;
 593                         } else if (c == 0)
 594                                 break;
 595
 596                         line[i] = c;
 597                 }
 598                 line[i] = 0;
 599
 600                 if (memcmp(line, field, l) == 0 && line[l] == '=') {
 601                         value = strdup(line + l + 1);
 602                         if (!value)
 603                                 return -ENOMEM;
 604
 605                         r = 1;
 606                         break;
 607                 }
 608
 609         } while (!done);
 610
 611         *_value = value;
 612         return r;
 613 }
 614
 615 bool pid_is_unwaited(pid_t pid) {
 616         /* Checks whether a PID is still valid at all, including a zombie */
 617
 618         if (pid < 0)
 619                 return false;
 620
 621         if (pid <= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
 622                 return true;
 623
 624         if (kill(pid, 0) >= 0)
 625                 return true;
 626
 627         return errno != ESRCH;
 628 }
 629
 630 bool pid_is_alive(pid_t pid) {
 631         int r;
 632
 633         /* Checks whether a PID is still valid and not a zombie */
 634
 635         if (pid < 0)
 636                 return false;
 637
 638         if (pid <= 1) /* If we or PID 1 would be a zombie, this code would not be running */
 639                 return true;
 640
 641         r = get_process_state(pid);
 642         if (r == -ESRCH || r == 'Z')
 643                 return false;
 644
 645         return true;
 646 }
 647
 648 int pid_from_same_root_fs(pid_t pid) {
 649         const char *root;
 650
 651         if (pid < 0)
 652                 return 0;
 653
 654         root = procfs_file_alloca(pid, "root");
 655
 656         return files_same(root, "/proc/1/root");
 657 }
 658
 659 bool is_main_thread(void) {
 660         static thread_local int cached = 0;
 661
 662         if (_unlikely_(cached == 0))
 663                 cached = getpid() == gettid() ? 1 : -1;
 664
 665         return cached > 0;
 666 }
 667
 668 noreturn void freeze(void) {
 669
 670         /* Make sure nobody waits for us on a socket anymore */
 671         close_all_fds(NULL, 0);
 672
 673         sync();
 674
 675         for (;;)
 676                 pause();
 677 }
 678
 679 bool oom_score_adjust_is_valid(int oa) {
 680         return oa >= OOM_SCORE_ADJ_MIN && oa <= OOM_SCORE_ADJ_MAX;
 681 }
 682
 683 unsigned long personality_from_string(const char *p) {
 684         int architecture;
 685
 686         if (!p)
 687                 return PERSONALITY_INVALID;
 688
 689         /* Parse a personality specifier. We use our own identifiers that indicate specific ABIs, rather than just
 690          * hints regarding the register size, since we want to keep things open for multiple locally supported ABIs for
 691          * the same register size. */
 692
 693         architecture = architecture_from_string(p);
 694         if (architecture < 0)
 695                 return PERSONALITY_INVALID;
 696
 697         if (architecture == native_architecture())
 698                 return PER_LINUX;
 699 #ifdef SECONDARY_ARCHITECTURE
 700         if (architecture == SECONDARY_ARCHITECTURE)
 701                 return PER_LINUX32;
 702 #endif
 703
 704         return PERSONALITY_INVALID;
 705 }
 706
 707 const char* personality_to_string(unsigned long p) {
 708         int architecture = _ARCHITECTURE_INVALID;
 709
 710         if (p == PER_LINUX)
 711                 architecture = native_architecture();
 712 #ifdef SECONDARY_ARCHITECTURE
 713         else if (p == PER_LINUX32)
 714                 architecture = SECONDARY_ARCHITECTURE;
 715 #endif
 716
 717         if (architecture < 0)
 718                 return NULL;
 719
 720         return architecture_to_string(architecture);
 721 }
 722
 723 void valgrind_summary_hack(void) {
 724 #ifdef HAVE_VALGRIND_VALGRIND_H
 725         if (getpid() == 1 && RUNNING_ON_VALGRIND) {
 726                 pid_t pid;
 727                 pid = raw_clone(SIGCHLD, NULL);
 728                 if (pid < 0)
 729                         log_emergency_errno(errno, "Failed to fork off valgrind helper: %m");
 730                 else if (pid == 0)
 731                         exit(EXIT_SUCCESS);
 732                 else {
 733                         log_info("Spawned valgrind helper as PID "PID_FMT".", pid);
 734                         (void) wait_for_terminate(pid, NULL);
 735                 }
 736         }
 737 #endif
 738 }
 739
 740 int pid_compare_func(const void *a, const void *b) {
 741         const pid_t *p = a, *q = b;
 742
 743         /* Suitable for usage in qsort() */
 744
 745         if (*p < *q)
 746                 return -1;
 747         if (*p > *q)
 748                 return 1;
 749         return 0;
 750 }
 751
 752 static const char *const ioprio_class_table[] = {
 753         [IOPRIO_CLASS_NONE] = "none",
 754         [IOPRIO_CLASS_RT] = "realtime",
 755         [IOPRIO_CLASS_BE] = "best-effort",
 756         [IOPRIO_CLASS_IDLE] = "idle"
 757 };
 758
 759 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ioprio_class, int, INT_MAX);
 760
 761 static const char *const sigchld_code_table[] = {
 762         [CLD_EXITED] = "exited",
 763         [CLD_KILLED] = "killed",
 764         [CLD_DUMPED] = "dumped",
 765         [CLD_TRAPPED] = "trapped",
 766         [CLD_STOPPED] = "stopped",
 767         [CLD_CONTINUED] = "continued",
 768 };
 769
 770 DEFINE_STRING_TABLE_LOOKUP(sigchld_code, int);
 771
 772 static const char* const sched_policy_table[] = {
 773         [SCHED_OTHER] = "other",
 774         [SCHED_BATCH] = "batch",
 775         [SCHED_IDLE] = "idle",
 776         [SCHED_FIFO] = "fifo",
 777         [SCHED_RR] = "rr"
 778 };
 779
 780 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(sched_policy, int, INT_MAX);