misc-utils/lslocks.c

   1 /*
   2  * lslocks(8) - list local system locks
   3  *
   4  * Copyright (C) 2012 Davidlohr Bueso <dave@gnu.org>
   5  *
   6  * Very generally based on lslk(8) by Victor A. Abell <abe@purdue.edu>
   7  * Since it stopped being maintained over a decade ago, this
   8  * program should be considered its replacement.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it would be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <getopt.h>
  28 #include <stdlib.h>
  29 #include <assert.h>
  30 #include <dirent.h>
  31 #include <unistd.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34
  35 #include <libmount.h>
  36 #include <libsmartcols.h>
  37
  38 #include "pathnames.h"
  39 #include "canonicalize.h"
  40 #include "nls.h"
  41 #include "xalloc.h"
  42 #include "strutils.h"
  43 #include "c.h"
  44 #include "list.h"
  45 #include "closestream.h"
  46 #include "optutils.h"
  47 #include "procutils.h"
  48
  49 /* column IDs */
  50 enum {
  51         COL_SRC = 0,
  52         COL_PID,
  53         COL_TYPE,
  54         COL_SIZE,
  55         COL_MODE,
  56         COL_M,
  57         COL_START,
  58         COL_END,
  59         COL_PATH,
  60         COL_BLOCKER
  61 };
  62
  63 /* column names */
  64 struct colinfo {
  65         const char *name; /* header */
  66         double     whint; /* width hint (N < 1 is in percent of termwidth) */
  67         int        flags; /* SCOLS_FL_* */
  68         const char *help;
  69 };
  70
  71 /* columns descriptions */
  72 static struct colinfo infos[] = {
  73         [COL_SRC]  = { "COMMAND",15, 0, N_("command of the process holding the lock") },
  74         [COL_PID]  = { "PID",     5, SCOLS_FL_RIGHT, N_("PID of the process holding the lock") },
  75         [COL_TYPE] = { "TYPE",    5, SCOLS_FL_RIGHT, N_("kind of lock: FL_FLOCK or FL_POSIX.") },
  76         [COL_SIZE] = { "SIZE",    4, SCOLS_FL_RIGHT, N_("size of the lock") },
  77         [COL_MODE] = { "MODE",    5, 0, N_("lock access mode") },
  78         [COL_M]    = { "M",       1, 0, N_("mandatory state of the lock: 0 (none), 1 (set)")},
  79         [COL_START] = { "START", 10, SCOLS_FL_RIGHT, N_("relative byte offset of the lock")},
  80         [COL_END]  = { "END",    10, SCOLS_FL_RIGHT, N_("ending offset of the lock")},
  81         [COL_PATH] = { "PATH",    0, SCOLS_FL_TRUNC, N_("path of the locked file")},
  82         [COL_BLOCKER] = { "BLOCKER", 0, SCOLS_FL_RIGHT, N_("PID of the process blocking the lock") }
  83 };
  84
  85 static int columns[ARRAY_SIZE(infos) * 2];
  86 static size_t ncolumns;
  87
  88 static pid_t pid = 0;
  89
  90 static struct libmnt_table *tab;                /* /proc/self/mountinfo */
  91
  92 /* basic output flags */
  93 static int no_headings;
  94 static int no_inaccessible;
  95 static int raw;
  96 static int json;
  97
  98 struct lock {
  99         struct list_head locks;
 100
 101         char *cmdname;
 102         pid_t pid;
 103         char *path;
 104         char *type;
 105         char *mode;
 106         off_t start;
 107         off_t end;
 108         unsigned int mandatory :1,
 109                      blocked   :1;
 110         char *size;
 111         int id;
 112 };
 113
 114 static void rem_lock(struct lock *lock)
 115 {
 116         if (!lock)
 117                 return;
 118
 119         free(lock->path);
 120         free(lock->size);
 121         free(lock->mode);
 122         free(lock->cmdname);
 123         free(lock->type);
 124         list_del(&lock->locks);
 125         free(lock);
 126 }
 127
 128 static void disable_columns_truncate(void)
 129 {
 130         size_t i;
 131
 132         for (i = 0; i < ARRAY_SIZE(infos); i++)
 133                 infos[i].flags &= ~SCOLS_FL_TRUNC;
 134 }
 135
 136 /*
 137  * Associate the device's mountpoint for a filename
 138  */
 139 static char *get_fallback_filename(dev_t dev)
 140 {
 141         struct libmnt_fs *fs;
 142         char *res = NULL;
 143
 144         if (!tab) {
 145                 tab = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO);
 146                 if (!tab)
 147                         return NULL;
 148         }
 149
 150         fs = mnt_table_find_devno(tab, dev, MNT_ITER_BACKWARD);
 151         if (!fs)
 152                 return NULL;
 153
 154         xasprintf(&res, "%s...", mnt_fs_get_target(fs));
 155         return res;
 156 }
 157
 158 /*
 159  * Return the absolute path of a file from
 160  * a given inode number (and its size)
 161  */
 162 static char *get_filename_sz(ino_t inode, pid_t lock_pid, size_t *size)
 163 {
 164         struct stat sb;
 165         struct dirent *dp;
 166         DIR *dirp;
 167         size_t len;
 168         int fd;
 169         char path[PATH_MAX], sym[PATH_MAX], *ret = NULL;
 170
 171         *size = 0;
 172         memset(path, 0, sizeof(path));
 173         memset(sym, 0, sizeof(sym));
 174
 175         /*
 176          * We know the pid so we don't have to
 177          * iterate the *entire* filesystem searching
 178          * for the damn file.
 179          */
 180         sprintf(path, "/proc/%d/fd/", lock_pid);
 181         if (!(dirp = opendir(path)))
 182                 return NULL;
 183
 184         if ((len = strlen(path)) >= (sizeof(path) - 2))
 185                 goto out;
 186
 187         if ((fd = dirfd(dirp)) < 0 )
 188                 goto out;
 189
 190         while ((dp = readdir(dirp))) {
 191                 if (!strcmp(dp->d_name, ".") ||
 192                     !strcmp(dp->d_name, ".."))
 193                         continue;
 194
 195                 /* care only for numerical descriptors */
 196                 if (!strtol(dp->d_name, (char **) NULL, 10))
 197                         continue;
 198
 199                 if (!fstatat(fd, dp->d_name, &sb, 0)
 200                     && inode != sb.st_ino)
 201                         continue;
 202
 203                 if ((len = readlinkat(fd, dp->d_name, sym, sizeof(sym) - 1)) < 1)
 204                         goto out;
 205
 206                 *size = sb.st_size;
 207                 sym[len] = '\0';
 208
 209                 ret = xstrdup(sym);
 210                 break;
 211         }
 212 out:
 213         closedir(dirp);
 214         return ret;
 215 }
 216
 217 /*
 218  * Return the inode number from a string
 219  */
 220 static ino_t get_dev_inode(char *str, dev_t *dev)
 221 {
 222         unsigned int maj = 0, min = 0;
 223         ino_t inum = 0;
 224
 225         sscanf(str, "%02x:%02x:%ju", &maj, &min, &inum);
 226
 227         *dev = (dev_t) makedev(maj, min);
 228         return inum;
 229 }
 230
 231 static int get_local_locks(struct list_head *locks)
 232 {
 233         int i;
 234         ino_t inode = 0;
 235         FILE *fp;
 236         char buf[PATH_MAX], *tok = NULL;
 237         size_t sz;
 238         struct lock *l;
 239         dev_t dev = 0;
 240
 241         if (!(fp = fopen(_PATH_PROC_LOCKS, "r")))
 242                 return -1;
 243
 244         while (fgets(buf, sizeof(buf), fp)) {
 245
 246                 l = xcalloc(1, sizeof(*l));
 247                 INIT_LIST_HEAD(&l->locks);
 248
 249                 for (tok = strtok(buf, " "), i = 0; tok;
 250                      tok = strtok(NULL, " "), i++) {
 251
 252                         /*
 253                          * /proc/locks has *exactly* 8 "blocks" of text
 254                          * separated by ' ' - check <kernel>/fs/locks.c
 255                          */
 256                         switch (i) {
 257                         case 0: /* ID: */
 258                                 tok[strlen(tok) - 1] = '\0';
 259                                 l->id = strtos32_or_err(tok, _("failed to parse ID"));
 260                                 break;
 261                         case 1: /* posix, flock, etc */
 262                                 if (strcmp(tok, "->") == 0) {   /* optional field */
 263                                         l->blocked = 1;
 264                                         i--;
 265                                 } else
 266                                         l->type = xstrdup(tok);
 267                                 break;
 268
 269                         case 2: /* is this a mandatory lock? other values are advisory or noinode */
 270                                 l->mandatory = *tok == 'M' ? 1 : 0;
 271                                 break;
 272                         case 3: /* lock mode */
 273                                 l->mode = xstrdup(tok);
 274                                 break;
 275
 276                         case 4: /* PID */
 277                                 /*
 278                                  * If user passed a pid we filter it later when adding
 279                                  * to the list, no need to worry now.
 280                                  */
 281                                 l->pid = strtos32_or_err(tok, _("failed to parse pid"));
 282                                 l->cmdname = proc_get_command_name(l->pid);
 283                                 if (!l->cmdname)
 284                                         l->cmdname = xstrdup(_("(unknown)"));
 285                                 break;
 286
 287                         case 5: /* device major:minor and inode number */
 288                                 inode = get_dev_inode(tok, &dev);
 289                                 break;
 290
 291                         case 6: /* start */
 292                                 l->start = !strcmp(tok, "EOF") ? 0 :
 293                                            strtou64_or_err(tok, _("failed to parse start"));
 294                                 break;
 295
 296                         case 7: /* end */
 297                                 /* replace '\n' character */
 298                                 tok[strlen(tok)-1] = '\0';
 299                                 l->end = !strcmp(tok, "EOF") ? 0 :
 300                                          strtou64_or_err(tok, _("failed to parse end"));
 301                                 break;
 302                         default:
 303                                 break;
 304                         }
 305                 }
 306
 307                 l->path = get_filename_sz(inode, l->pid, &sz);
 308
 309                 /* no permissions -- ignore */
 310                 if (!l->path && no_inaccessible) {
 311                         rem_lock(l);
 312                         continue;
 313                 }
 314
 315                 if (!l->path) {
 316                         /* probably no permission to peek into l->pid's path */
 317                         l->path = get_fallback_filename(dev);
 318                         l->size = xstrdup("");
 319                 } else
 320                         /* avoid leaking */
 321                         l->size = size_to_human_string(SIZE_SUFFIX_1LETTER, sz);
 322
 323                 list_add(&l->locks, locks);
 324         }
 325
 326         fclose(fp);
 327         return 0;
 328 }
 329
 330 static int column_name_to_id(const char *name, size_t namesz)
 331 {
 332         size_t i;
 333
 334         assert(name);
 335
 336         for (i = 0; i < ARRAY_SIZE(infos); i++) {
 337                 const char *cn = infos[i].name;
 338
 339                 if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
 340                         return i;
 341         }
 342         warnx(_("unknown column: %s"), name);
 343         return -1;
 344 }
 345
 346 static inline int get_column_id(int num)
 347 {
 348         assert(num >= 0);
 349         assert((size_t) num < ncolumns);
 350         assert(columns[num] < (int) ARRAY_SIZE(infos));
 351
 352         return columns[num];
 353 }
 354
 355
 356 static inline struct colinfo *get_column_info(unsigned num)
 357 {
 358         return &infos[ get_column_id(num) ];
 359 }
 360
 361 static pid_t get_blocker(int id, struct list_head *locks)
 362 {
 363         struct list_head *p;
 364
 365         list_for_each(p, locks) {
 366                 struct lock *l = list_entry(p, struct lock, locks);
 367
 368                 if (l->id == id && !l->blocked)
 369                         return l->pid;
 370         }
 371
 372         return 0;
 373 }
 374
 375 static void add_scols_line(struct libscols_table *table, struct lock *l, struct list_head *locks)
 376 {
 377         size_t i;
 378         struct libscols_line *line;
 379         /*
 380          * Whenever cmdname or filename is NULL it is most
 381          * likely  because there's no read permissions
 382          * for the specified process.
 383          */
 384         const char *notfnd = "";
 385
 386         assert(l);
 387         assert(table);
 388
 389         line = scols_table_new_line(table, NULL);
 390         if (!line) {
 391                 warn(_("failed to add line to output"));
 392                 return;
 393         }
 394
 395         for (i = 0; i < ncolumns; i++) {
 396                 char *str = NULL;
 397
 398                 switch (get_column_id(i)) {
 399                 case COL_SRC:
 400                         xasprintf(&str, "%s", l->cmdname ? l->cmdname : notfnd);
 401                         break;
 402                 case COL_PID:
 403                         xasprintf(&str, "%d", l->pid);
 404                         break;
 405                 case COL_TYPE:
 406                         xasprintf(&str, "%s", l->type);
 407                         break;
 408                 case COL_SIZE:
 409                         xasprintf(&str, "%s", l->size);
 410                         break;
 411                 case COL_MODE:
 412                         xasprintf(&str, "%s%s", l->mode, l->blocked ? "*" : "");
 413                         break;
 414                 case COL_M:
 415                         xasprintf(&str, "%d", l->mandatory ? 1 : 0);
 416                         break;
 417                 case COL_START:
 418                         xasprintf(&str, "%jd", l->start);
 419                         break;
 420                 case COL_END:
 421                         xasprintf(&str, "%jd", l->end);
 422                         break;
 423                 case COL_PATH:
 424                         xasprintf(&str, "%s", l->path ? l->path : notfnd);
 425                         break;
 426                 case COL_BLOCKER:
 427                 {
 428                         pid_t bl = l->blocked && l->id ?
 429                                                 get_blocker(l->id, locks) : 0;
 430                         if (bl)
 431                                 xasprintf(&str, "%d", (int) bl);
 432                 }
 433                 default:
 434                         break;
 435                 }
 436
 437                 if (str)
 438                         scols_line_set_data(line, i, str);
 439         }
 440 }
 441
 442 static int show_locks(struct list_head *locks)
 443 {
 444         int rc = 0;
 445         size_t i;
 446         struct list_head *p, *pnext;
 447         struct libscols_table *table;
 448
 449         table = scols_new_table();
 450         if (!table) {
 451                 warn(_("failed to initialize output table"));
 452                 return -1;
 453         }
 454         scols_table_enable_raw(table, raw);
 455         scols_table_enable_json(table, json);
 456         scols_table_enable_noheadings(table, no_headings);
 457
 458         if (json)
 459                 scols_table_set_name(table, "locks");
 460
 461         for (i = 0; i < ncolumns; i++) {
 462                 struct colinfo *col = get_column_info(i);
 463
 464                 if (!scols_table_new_column(table, col->name, col->whint, col->flags)) {
 465                         warnx(_("failed to initialize output column"));
 466                         rc = -1;
 467                         goto done;
 468                 }
 469         }
 470
 471         /* prepare data for output */
 472         list_for_each(p, locks) {
 473                 struct lock *l = list_entry(p, struct lock, locks);
 474
 475                 if (pid && pid != l->pid)
 476                         continue;
 477
 478                 add_scols_line(table, l, locks);
 479         }
 480
 481         /* destroy the list */
 482         list_for_each_safe(p, pnext, locks) {
 483                 struct lock *l = list_entry(p, struct lock, locks);
 484                 rem_lock(l);
 485         }
 486
 487         scols_print_table(table);
 488 done:
 489         scols_unref_table(table);
 490         return rc;
 491 }
 492
 493
 494 static void __attribute__ ((__noreturn__)) usage(FILE * out)
 495 {
 496         size_t i;
 497
 498         fputs(USAGE_HEADER, out);
 499
 500         fprintf(out,
 501                 _(" %s [options]\n"), program_invocation_short_name);
 502
 503         fputs(USAGE_SEPARATOR, out);
 504         fputs(_("List local system locks.\n"), out);
 505
 506         fputs(USAGE_OPTIONS, out);
 507         fputs(_(" -J, --json             use JSON output format\n"), out);
 508         fputs(_(" -i, --noinaccessible   ignore locks without read permissions\n"), out);
 509         fputs(_(" -n, --noheadings       don't print headings\n"), out);
 510         fputs(_(" -o, --output <list>    define which output columns to use\n"), out);
 511         fputs(_(" -p, --pid <pid>        display only locks held by this process\n"), out);
 512         fputs(_(" -r, --raw              use the raw output format\n"), out);
 513         fputs(_(" -u, --notruncate       don't truncate text in columns\n"), out);
 514
 515         fputs(USAGE_SEPARATOR, out);
 516         fputs(USAGE_HELP, out);
 517         fputs(USAGE_VERSION, out);
 518
 519         fputs(_("\nAvailable columns (for --output):\n"), out);
 520
 521         for (i = 0; i < ARRAY_SIZE(infos); i++)
 522                 fprintf(out, " %11s  %s\n", infos[i].name, _(infos[i].help));
 523
 524         fprintf(out, USAGE_MAN_TAIL("lslocks(8)"));
 525
 526         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 527 }
 528
 529 int main(int argc, char *argv[])
 530 {
 531         int c, rc = 0;
 532         struct list_head locks;
 533         char *outarg = NULL;
 534         static const struct option long_opts[] = {
 535                 { "json",       no_argument,       NULL, 'J' },
 536                 { "pid",        required_argument, NULL, 'p' },
 537                 { "help",       no_argument,       NULL, 'h' },
 538                 { "output",     required_argument, NULL, 'o' },
 539                 { "notruncate", no_argument,       NULL, 'u' },
 540                 { "version",    no_argument,       NULL, 'V' },
 541                 { "noheadings", no_argument,       NULL, 'n' },
 542                 { "raw",        no_argument,       NULL, 'r' },
 543                 { "noinaccessible", no_argument, NULL, 'i' },
 544                 { NULL, 0, NULL, 0 }
 545         };
 546
 547         static const ul_excl_t excl[] = {       /* rows and cols in ASCII order */
 548                 { 'J','r' },
 549                 { 0 }
 550         };
 551         int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
 552         setlocale(LC_ALL, "");
 553         bindtextdomain(PACKAGE, LOCALEDIR);
 554         textdomain(PACKAGE);
 555         atexit(close_stdout);
 556
 557         while ((c = getopt_long(argc, argv,
 558                                 "iJp:o:nruhV", long_opts, NULL)) != -1) {
 559
 560                 err_exclusive_options(c, long_opts, excl, excl_st);
 561
 562                 switch(c) {
 563                 case 'i':
 564                         no_inaccessible = 1;
 565                         break;
 566                 case 'J':
 567                         json = 1;
 568                         break;
 569                 case 'p':
 570                         pid = strtos32_or_err(optarg, _("invalid PID argument"));
 571                         break;
 572                 case 'o':
 573                         outarg = optarg;
 574                         break;
 575                 case 'V':
 576                         printf(UTIL_LINUX_VERSION);
 577                         return EXIT_SUCCESS;
 578                 case 'h':
 579                         usage(stdout);
 580                 case 'n':
 581                         no_headings = 1;
 582                         break;
 583                 case 'r':
 584                         raw = 1;
 585                         break;
 586                 case 'u':
 587                         disable_columns_truncate();
 588                         break;
 589                 default:
 590                         errtryhelp(EXIT_FAILURE);
 591                 }
 592         }
 593
 594         INIT_LIST_HEAD(&locks);
 595
 596         if (!ncolumns) {
 597                 /* default columns */
 598                 columns[ncolumns++] = COL_SRC;
 599                 columns[ncolumns++] = COL_PID;
 600                 columns[ncolumns++] = COL_TYPE;
 601                 columns[ncolumns++] = COL_SIZE;
 602                 columns[ncolumns++] = COL_MODE;
 603                 columns[ncolumns++] = COL_M;
 604                 columns[ncolumns++] = COL_START;
 605                 columns[ncolumns++] = COL_END;
 606                 columns[ncolumns++] = COL_PATH;
 607         }
 608
 609         if (outarg && string_add_to_idarray(outarg, columns, ARRAY_SIZE(columns),
 610                                          &ncolumns, column_name_to_id) < 0)
 611                 return EXIT_FAILURE;
 612
 613         scols_init_debug(0);
 614
 615         rc = get_local_locks(&locks);
 616
 617         if (!rc && !list_empty(&locks))
 618                 rc = show_locks(&locks);
 619
 620         mnt_unref_table(tab);
 621         return rc;
 622 }