lustre/obdclass/jobid.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2014, Intel Corporation.
  27  *
  28  * Copyright 2017 Cray Inc, all rights reserved.
  29  * Author: Ben Evans.
  30  *
  31  * Store PID->JobID mappings
  32  */
  33
  34 #define DEBUG_SUBSYSTEM S_RPC
  35 #include <linux/user_namespace.h>
  36 #ifdef HAVE_UIDGID_HEADER
  37 #include <linux/uidgid.h>
  38 #endif
  39 #include <linux/utsname.h>
  40
  41 #include <libcfs/libcfs.h>
  42 #include <obd_support.h>
  43 #include <obd_class.h>
  44 #include <lustre_net.h>
  45
  46 static struct cfs_hash *jobid_hash;
  47 static struct cfs_hash_ops jobid_hash_ops;
  48 spinlock_t jobid_hash_lock;
  49
  50 #define RESCAN_INTERVAL 30
  51 #define DELETE_INTERVAL 300
  52
  53 char obd_jobid_var[JOBSTATS_JOBID_VAR_MAX_LEN + 1] = JOBSTATS_DISABLE;
  54 char obd_jobid_name[LUSTRE_JOBID_SIZE] = "%e.%u";
  55
  56 /**
  57  * Structure to store a single PID->JobID mapping
  58  */
  59 struct jobid_pid_map {
  60         struct hlist_node       jp_hash;
  61         time64_t                jp_time;
  62         spinlock_t              jp_lock; /* protects jp_jobid */
  63         char                    jp_jobid[LUSTRE_JOBID_SIZE];
  64         unsigned int            jp_joblen;
  65         atomic_t                jp_refcount;
  66         pid_t                   jp_pid;
  67 };
  68
  69 /*
  70  * Jobid can be set for a session (see setsid(2)) by writing to
  71  * a sysfs file from any process in that session.
  72  * The jobids are stored in a hash table indexed by the relevant
  73  * struct pid.  We periodically look for entries where the pid has
  74  * no PIDTYPE_SID tasks any more, and prune them.  This happens within
  75  * 5 seconds of a jobid being added, and every 5 minutes when jobids exist,
  76  * but none are added.
  77  */
  78 #define JOBID_EXPEDITED_CLEAN (5)
  79 #define JOBID_BACKGROUND_CLEAN (5 * 60)
  80
  81 struct session_jobid {
  82         struct pid              *sj_session;
  83         struct rhash_head       sj_linkage;
  84         struct rcu_head         sj_rcu;
  85         char                    sj_jobid[1];
  86 };
  87
  88 static const struct rhashtable_params jobid_params = {
  89         .key_len        = sizeof(struct pid *),
  90         .key_offset     = offsetof(struct session_jobid, sj_session),
  91         .head_offset    = offsetof(struct session_jobid, sj_linkage),
  92 };
  93
  94 static struct rhashtable session_jobids;
  95
  96 /*
  97  * jobid_current must be called with rcu_read_lock held.
  98  * if it returns non-NULL, the string can only be used
  99  * until rcu_read_unlock is called.
 100  */
 101 char *jobid_current(void)
 102 {
 103         struct pid *sid = task_session(current);
 104         struct session_jobid *sj;
 105
 106         sj = rhashtable_lookup_fast(&session_jobids, &sid, jobid_params);
 107         if (sj)
 108                 return sj->sj_jobid;
 109         return NULL;
 110 }
 111
 112 static void jobid_prune_expedite(void);
 113 /*
 114  * jobid_set_current will try to add a new entry
 115  * to the table.  If one exists with the same key, the
 116  * jobid will be replaced
 117  */
 118 int jobid_set_current(char *jobid)
 119 {
 120         struct pid *sid;
 121         struct session_jobid *sj, *origsj;
 122         int ret;
 123         int len = strlen(jobid);
 124
 125         sj = kmalloc(sizeof(*sj) + len, GFP_KERNEL);
 126         if (!sj)
 127                 return -ENOMEM;
 128         rcu_read_lock();
 129         sid = task_session(current);
 130         sj->sj_session = get_pid(sid);
 131         strncpy(sj->sj_jobid, jobid, len+1);
 132         origsj = rhashtable_lookup_get_insert_fast(&session_jobids,
 133                                                    &sj->sj_linkage,
 134                                                    jobid_params);
 135         if (origsj == NULL) {
 136                 /* successful insert */
 137                 rcu_read_unlock();
 138                 jobid_prune_expedite();
 139                 return 0;
 140         }
 141
 142         if (IS_ERR(origsj)) {
 143                 put_pid(sj->sj_session);
 144                 kfree(sj);
 145                 rcu_read_unlock();
 146                 return PTR_ERR(origsj);
 147         }
 148         ret = rhashtable_replace_fast(&session_jobids,
 149                                       &origsj->sj_linkage,
 150                                       &sj->sj_linkage,
 151                                       jobid_params);
 152         if (ret) {
 153                 put_pid(sj->sj_session);
 154                 kfree(sj);
 155                 rcu_read_unlock();
 156                 return ret;
 157         }
 158         put_pid(origsj->sj_session);
 159         rcu_read_unlock();
 160         kfree_rcu(origsj, sj_rcu);
 161         jobid_prune_expedite();
 162
 163         return 0;
 164 }
 165
 166 static void jobid_free(void *vsj, void *arg)
 167 {
 168         struct session_jobid *sj = vsj;
 169
 170         put_pid(sj->sj_session);
 171         kfree(sj);
 172 }
 173
 174 static void jobid_prune(struct work_struct *work);
 175 static DECLARE_DELAYED_WORK(jobid_prune_work, jobid_prune);
 176 static int jobid_prune_expedited;
 177 static void jobid_prune(struct work_struct *work)
 178 {
 179         int remaining = 0;
 180         struct rhashtable_iter iter;
 181         struct session_jobid *sj;
 182
 183         jobid_prune_expedited = 0;
 184         rhashtable_walk_enter(&session_jobids, &iter);
 185         rhashtable_walk_start(&iter);
 186         while ((sj = rhashtable_walk_next(&iter)) != NULL) {
 187                 if (!hlist_empty(&sj->sj_session->tasks[PIDTYPE_SID])) {
 188                         remaining++;
 189                         continue;
 190                 }
 191                 if (rhashtable_remove_fast(&session_jobids,
 192                                            &sj->sj_linkage,
 193                                            jobid_params) == 0) {
 194                         put_pid(sj->sj_session);
 195                         kfree_rcu(sj, sj_rcu);
 196                 }
 197         }
 198         rhashtable_walk_stop(&iter);
 199         rhashtable_walk_exit(&iter);
 200         if (remaining)
 201                 schedule_delayed_work(&jobid_prune_work,
 202                                       cfs_time_seconds(JOBID_BACKGROUND_CLEAN));
 203 }
 204
 205 static void jobid_prune_expedite(void)
 206 {
 207         if (!jobid_prune_expedited) {
 208                 jobid_prune_expedited = 1;
 209                 mod_delayed_work(system_wq, &jobid_prune_work,
 210                                  cfs_time_seconds(JOBID_EXPEDITED_CLEAN));
 211         }
 212 }
 213
 214 /*
 215  * Get jobid of current process by reading the environment variable
 216  * stored in between the "env_start" & "env_end" of task struct.
 217  *
 218  * If some job scheduler doesn't store jobid in the "env_start/end",
 219  * then an upcall could be issued here to get the jobid by utilizing
 220  * the userspace tools/API. Then, the jobid must be cached.
 221  */
 222 int jobid_get_from_environ(char *jobid_var, char *jobid, int *jobid_len)
 223 {
 224         static bool printed;
 225         int rc;
 226
 227         rc = cfs_get_environ(jobid_var, jobid, jobid_len);
 228         if (!rc)
 229                 goto out;
 230
 231         if (unlikely(rc == -EOVERFLOW && !printed)) {
 232                 /* For the PBS_JOBID and LOADL_STEP_ID keys (which are
 233                  * variable length strings instead of just numbers), it
 234                  * might make sense to keep the unique parts for JobID,
 235                  * instead of just returning an error.  That means a
 236                  * larger temp buffer for cfs_get_environ(), then
 237                  * truncating the string at some separator to fit into
 238                  * the specified jobid_len.  Fix later if needed. */
 239                 LCONSOLE_WARN("jobid: '%s' value too large (%d)\n",
 240                               obd_jobid_var, *jobid_len);
 241                 printed = true;
 242                 rc = 0;
 243         }
 244         if (rc) {
 245                 CDEBUG((rc == -ENOENT || rc == -EINVAL ||
 246                         rc == -EDEADLK) ? D_INFO : D_ERROR,
 247                        "jobid: get '%s' failed: rc = %d\n",
 248                        obd_jobid_var, rc);
 249         }
 250
 251 out:
 252         return rc;
 253 }
 254
 255 /*
 256  * jobid_should_free_item
 257  *
 258  * Each item is checked to see if it should be released
 259  * Removed from hash table by caller
 260  * Actually freed in jobid_put_locked
 261  *
 262  * Returns 1 if item is to be freed, 0 if it is to be kept
 263  */
 264
 265 static int jobid_should_free_item(void *obj, void *data)
 266 {
 267         char *jobid = data;
 268         struct jobid_pid_map *pidmap = obj;
 269         int rc = 0;
 270
 271         if (obj == NULL)
 272                 return 0;
 273
 274         if (jobid == NULL) {
 275                 WARN_ON_ONCE(atomic_read(&pidmap->jp_refcount) != 1);
 276                 return 1;
 277         }
 278
 279         spin_lock(&pidmap->jp_lock);
 280         /* prevent newly inserted items from deleting */
 281         if (jobid[0] == '\0' && atomic_read(&pidmap->jp_refcount) == 1)
 282                 rc = 1;
 283         else if (ktime_get_real_seconds() - pidmap->jp_time > DELETE_INTERVAL)
 284                 rc = 1;
 285         else if (strcmp(pidmap->jp_jobid, jobid) == 0)
 286                 rc = 1;
 287         spin_unlock(&pidmap->jp_lock);
 288
 289         return rc;
 290 }
 291
 292 /*
 293  * jobid_name_is_valid
 294  *
 295  * Checks if the jobid is a Lustre process
 296  *
 297  * Returns true if jobid is valid
 298  * Returns false if jobid looks like it's a Lustre process
 299  */
 300 static bool jobid_name_is_valid(char *jobid)
 301 {
 302         const char *const lustre_reserved[] = { "ll_ping", "ptlrpc",
 303                                                 "ldlm", "ll_sa", NULL };
 304         int i;
 305
 306         if (jobid[0] == '\0')
 307                 return false;
 308
 309         for (i = 0; lustre_reserved[i] != NULL; i++) {
 310                 if (strncmp(jobid, lustre_reserved[i],
 311                             strlen(lustre_reserved[i])) == 0)
 312                         return false;
 313         }
 314         return true;
 315 }
 316
 317 /*
 318  * jobid_get_from_cache()
 319  *
 320  * Returns contents of jobid_var from process environment for current PID,
 321  * or from the per-session jobid table.
 322  * Values fetch from process environment will be cached for some time to avoid
 323  * the overhead of scanning the environment.
 324  *
 325  * Return: -ENOMEM if allocating a new pidmap fails
 326  *         -ENOENT if no entry could be found
 327  *         +ve string length for success (something was returned in jobid)
 328  */
 329 static int jobid_get_from_cache(char *jobid, size_t joblen)
 330 {
 331         static time64_t last_expire;
 332         bool expire_cache = false;
 333         pid_t pid = current_pid();
 334         struct jobid_pid_map *pidmap = NULL;
 335         time64_t now = ktime_get_real_seconds();
 336         int rc = 0;
 337         ENTRY;
 338
 339         if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0) {
 340                 char *jid;
 341
 342                 rcu_read_lock();
 343                 jid = jobid_current();
 344                 if (jid) {
 345                         strlcpy(jobid, jid, joblen);
 346                         joblen = strlen(jobid);
 347                 } else {
 348                         rc = -ENOENT;
 349                 }
 350                 rcu_read_unlock();
 351                 GOTO(out, rc);
 352         }
 353
 354         LASSERT(jobid_hash != NULL);
 355
 356         /* scan hash periodically to remove old PID entries from cache */
 357         spin_lock(&jobid_hash_lock);
 358         if (unlikely(last_expire + DELETE_INTERVAL <= now)) {
 359                 expire_cache = true;
 360                 last_expire = now;
 361         }
 362         spin_unlock(&jobid_hash_lock);
 363
 364         if (expire_cache)
 365                 cfs_hash_cond_del(jobid_hash, jobid_should_free_item,
 366                                   "intentionally_bad_jobid");
 367
 368         /* first try to find PID in the hash and use that value */
 369         pidmap = cfs_hash_lookup(jobid_hash, &pid);
 370         if (pidmap == NULL) {
 371                 struct jobid_pid_map *pidmap2;
 372
 373                 OBD_ALLOC_PTR(pidmap);
 374                 if (pidmap == NULL)
 375                         GOTO(out, rc = -ENOMEM);
 376
 377                 pidmap->jp_pid = pid;
 378                 pidmap->jp_time = 0;
 379                 pidmap->jp_jobid[0] = '\0';
 380                 spin_lock_init(&pidmap->jp_lock);
 381                 INIT_HLIST_NODE(&pidmap->jp_hash);
 382                 /*
 383                  * @pidmap might be reclaimed just after it is added into
 384                  * hash list, init @jp_refcount as 1 to make sure memory
 385                  * could be not freed during access.
 386                  */
 387                 atomic_set(&pidmap->jp_refcount, 1);
 388
 389                 /*
 390                  * Add the newly created map to the hash, on key collision we
 391                  * lost a racing addition and must destroy our newly allocated
 392                  * map.  The object which exists in the hash will be returned.
 393                  */
 394                 pidmap2 = cfs_hash_findadd_unique(jobid_hash, &pid,
 395                                                   &pidmap->jp_hash);
 396                 if (unlikely(pidmap != pidmap2)) {
 397                         CDEBUG(D_INFO, "jobid: duplicate found for PID=%u\n",
 398                                pid);
 399                         OBD_FREE_PTR(pidmap);
 400                         pidmap = pidmap2;
 401                 }
 402         }
 403
 404         /*
 405          * If pidmap is old (this is always true for new entries) refresh it.
 406          * If obd_jobid_var is not found, cache empty entry and try again
 407          * later, to avoid repeat lookups for PID if obd_jobid_var missing.
 408          */
 409         spin_lock(&pidmap->jp_lock);
 410         if (pidmap->jp_time + RESCAN_INTERVAL <= now) {
 411                 char env_jobid[LUSTRE_JOBID_SIZE] = "";
 412                 int env_len = sizeof(env_jobid);
 413
 414                 pidmap->jp_time = now;
 415
 416                 spin_unlock(&pidmap->jp_lock);
 417                 rc = jobid_get_from_environ(obd_jobid_var, env_jobid, &env_len);
 418
 419                 CDEBUG(D_INFO, "jobid: PID mapping established: %d->%s\n",
 420                        pidmap->jp_pid, env_jobid);
 421                 spin_lock(&pidmap->jp_lock);
 422                 if (!rc) {
 423                         pidmap->jp_joblen = env_len;
 424                         strlcpy(pidmap->jp_jobid, env_jobid,
 425                                 sizeof(pidmap->jp_jobid));
 426                         rc = 0;
 427                 } else if (rc == -ENOENT) {
 428                         /* It might have been deleted, clear out old entry */
 429                         pidmap->jp_joblen = 0;
 430                         pidmap->jp_jobid[0] = '\0';
 431                 }
 432         }
 433
 434         /*
 435          * Regardless of how pidmap was found, if it contains a valid entry
 436          * use that for now.  If there was a technical error (e.g. -ENOMEM)
 437          * use the old cached value until it can be looked up again properly.
 438          * If a cached missing entry was found, return -ENOENT.
 439          */
 440         if (pidmap->jp_joblen) {
 441                 strlcpy(jobid, pidmap->jp_jobid, joblen);
 442                 joblen = pidmap->jp_joblen;
 443                 rc = 0;
 444         } else if (!rc) {
 445                 rc = -ENOENT;
 446         }
 447         spin_unlock(&pidmap->jp_lock);
 448
 449         cfs_hash_put(jobid_hash, &pidmap->jp_hash);
 450
 451         EXIT;
 452 out:
 453         return rc < 0 ? rc : joblen;
 454 }
 455
 456 /*
 457  * jobid_interpret_string()
 458  *
 459  * Interpret the jobfmt string to expand specified fields, like coredumps do:
 460  *   %e = executable
 461  *   %g = gid
 462  *   %h = hostname
 463  *   %j = jobid from environment
 464  *   %p = pid
 465  *   %u = uid
 466  *
 467  * Unknown escape strings are dropped.  Other characters are copied through,
 468  * excluding whitespace (to avoid making jobid parsing difficult).
 469  *
 470  * Return: -EOVERFLOW if the expanded string does not fit within @joblen
 471  *         0 for success
 472  */
 473 static int jobid_interpret_string(const char *jobfmt, char *jobid,
 474                                   ssize_t joblen)
 475 {
 476         char c;
 477
 478         while ((c = *jobfmt++) && joblen > 1) {
 479                 char f;
 480                 int l;
 481
 482                 if (isspace(c)) /* Don't allow embedded spaces */
 483                         continue;
 484
 485                 if (c != '%') {
 486                         *jobid = c;
 487                         joblen--;
 488                         jobid++;
 489                         continue;
 490                 }
 491
 492                 switch ((f = *jobfmt++)) {
 493                 case 'e': /* executable name */
 494                         l = snprintf(jobid, joblen, "%s", current_comm());
 495                         break;
 496                 case 'g': /* group ID */
 497                         l = snprintf(jobid, joblen, "%u",
 498                                      from_kgid(&init_user_ns, current_fsgid()));
 499                         break;
 500                 case 'h': /* hostname */
 501                         l = snprintf(jobid, joblen, "%s",
 502                                      init_utsname()->nodename);
 503                         break;
 504                 case 'j': /* jobid stored in process environment */
 505                         l = jobid_get_from_cache(jobid, joblen);
 506                         if (l < 0)
 507                                 l = 0;
 508                         break;
 509                 case 'p': /* process ID */
 510                         l = snprintf(jobid, joblen, "%u", current_pid());
 511                         break;
 512                 case 'u': /* user ID */
 513                         l = snprintf(jobid, joblen, "%u",
 514                                      from_kuid(&init_user_ns, current_fsuid()));
 515                         break;
 516                 case '\0': /* '%' at end of format string */
 517                         l = 0;
 518                         goto out;
 519                 default: /* drop unknown %x format strings */
 520                         l = 0;
 521                         break;
 522                 }
 523                 jobid += l;
 524                 joblen -= l;
 525         }
 526         /*
 527          * This points at the end of the buffer, so long as jobid is always
 528          * incremented the same amount as joblen is decremented.
 529          */
 530 out:
 531         jobid[joblen - 1] = '\0';
 532
 533         return joblen < 0 ? -EOVERFLOW : 0;
 534 }
 535
 536 /*
 537  * Hash initialization, copied from server-side job stats bucket sizes
 538  */
 539 #define HASH_JOBID_BKT_BITS 5
 540 #define HASH_JOBID_CUR_BITS 7
 541 #define HASH_JOBID_MAX_BITS 12
 542
 543 int jobid_cache_init(void)
 544 {
 545         int rc = 0;
 546         ENTRY;
 547
 548         if (jobid_hash)
 549                 return 0;
 550
 551         spin_lock_init(&jobid_hash_lock);
 552         jobid_hash = cfs_hash_create("JOBID_HASH", HASH_JOBID_CUR_BITS,
 553                                      HASH_JOBID_MAX_BITS, HASH_JOBID_BKT_BITS,
 554                                      0, CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
 555                                      &jobid_hash_ops, CFS_HASH_DEFAULT);
 556         if (!jobid_hash) {
 557                 rc = -ENOMEM;
 558         } else {
 559                 rc = rhashtable_init(&session_jobids, &jobid_params);
 560                 if (rc) {
 561                         cfs_hash_putref(jobid_hash);
 562                         jobid_hash = NULL;
 563                 }
 564         }
 565
 566         RETURN(rc);
 567 }
 568 EXPORT_SYMBOL(jobid_cache_init);
 569
 570 void jobid_cache_fini(void)
 571 {
 572         struct cfs_hash *tmp_hash;
 573         ENTRY;
 574
 575         spin_lock(&jobid_hash_lock);
 576         tmp_hash = jobid_hash;
 577         jobid_hash = NULL;
 578         spin_unlock(&jobid_hash_lock);
 579
 580         cancel_delayed_work_sync(&jobid_prune_work);
 581
 582         if (tmp_hash != NULL) {
 583                 cfs_hash_cond_del(tmp_hash, jobid_should_free_item, NULL);
 584                 cfs_hash_putref(tmp_hash);
 585
 586                 rhashtable_free_and_destroy(&session_jobids, jobid_free, NULL);
 587         }
 588
 589
 590         EXIT;
 591 }
 592 EXPORT_SYMBOL(jobid_cache_fini);
 593
 594 /*
 595  * Hash operations for pid<->jobid
 596  */
 597 static unsigned jobid_hashfn(struct cfs_hash *hs, const void *key,
 598                              unsigned mask)
 599 {
 600         return cfs_hash_djb2_hash(key, sizeof(pid_t), mask);
 601 }
 602
 603 static void *jobid_key(struct hlist_node *hnode)
 604 {
 605         struct jobid_pid_map *pidmap;
 606
 607         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 608         return &pidmap->jp_pid;
 609 }
 610
 611 static int jobid_keycmp(const void *key, struct hlist_node *hnode)
 612 {
 613         const pid_t *pid_key1;
 614         const pid_t *pid_key2;
 615
 616         LASSERT(key != NULL);
 617         pid_key1 = (pid_t *)key;
 618         pid_key2 = (pid_t *)jobid_key(hnode);
 619
 620         return *pid_key1 == *pid_key2;
 621 }
 622
 623 static void *jobid_object(struct hlist_node *hnode)
 624 {
 625         return hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 626 }
 627
 628 static void jobid_get(struct cfs_hash *hs, struct hlist_node *hnode)
 629 {
 630         struct jobid_pid_map *pidmap;
 631
 632         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 633
 634         atomic_inc(&pidmap->jp_refcount);
 635 }
 636
 637 static void jobid_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
 638 {
 639         struct jobid_pid_map *pidmap;
 640
 641         if (hnode == NULL)
 642                 return;
 643
 644         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 645         LASSERT(atomic_read(&pidmap->jp_refcount) > 0);
 646         if (atomic_dec_and_test(&pidmap->jp_refcount)) {
 647                 CDEBUG(D_INFO, "Freeing: %d->%s\n",
 648                        pidmap->jp_pid, pidmap->jp_jobid);
 649
 650                 OBD_FREE_PTR(pidmap);
 651         }
 652 }
 653
 654 static struct cfs_hash_ops jobid_hash_ops = {
 655         .hs_hash        = jobid_hashfn,
 656         .hs_keycmp      = jobid_keycmp,
 657         .hs_key         = jobid_key,
 658         .hs_object      = jobid_object,
 659         .hs_get         = jobid_get,
 660         .hs_put         = jobid_put_locked,
 661         .hs_put_locked  = jobid_put_locked,
 662 };
 663
 664 /**
 665  * Generate the job identifier string for this process for tracking purposes.
 666  *
 667  * Fill in @jobid string based on the value of obd_jobid_var:
 668  * JOBSTATS_DISABLE:      none
 669  * JOBSTATS_NODELOCAL:    content of obd_jobid_name (jobid_interpret_string())
 670  * JOBSTATS_PROCNAME_UID: process name/UID
 671  * JOBSTATS_SESSION       per-session value set by
 672  *                            /sys/fs/lustre/jobid_this_session
 673  * anything else:         look up obd_jobid_var in the processes environment
 674  *
 675  * Return -ve error number, 0 on success.
 676  */
 677 int lustre_get_jobid(char *jobid, size_t joblen)
 678 {
 679         int rc = 0;
 680         ENTRY;
 681
 682         if (unlikely(joblen < 2)) {
 683                 if (joblen == 1)
 684                         jobid[0] = '\0';
 685                 RETURN(-EINVAL);
 686         }
 687
 688         if (strcmp(obd_jobid_var, JOBSTATS_DISABLE) == 0) {
 689                 /* Jobstats isn't enabled */
 690                 memset(jobid, 0, joblen);
 691         } else if (strcmp(obd_jobid_var, JOBSTATS_NODELOCAL) == 0) {
 692                 /* Whole node dedicated to single job */
 693                 rc = jobid_interpret_string(obd_jobid_name, jobid, joblen);
 694         } else if (strcmp(obd_jobid_var, JOBSTATS_PROCNAME_UID) == 0) {
 695                 rc = jobid_interpret_string("%e.%u", jobid, joblen);
 696         } else if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0) {
 697                 char *jid;
 698
 699                 rcu_read_lock();
 700                 jid = jobid_current();
 701                 if (jid)
 702                         strlcpy(jobid, jid, sizeof(jobid));
 703                 rcu_read_unlock();
 704         } else if (jobid_name_is_valid(current_comm())) {
 705                 /*
 706                  * obd_jobid_var holds the jobid environment variable name.
 707                  * Skip initial check if obd_jobid_name already uses "%j",
 708                  * otherwise try just "%j" first, then fall back to whatever
 709                  * is in obd_jobid_name if obd_jobid_var is not found.
 710                  */
 711                 rc = -EAGAIN;
 712                 if (!strnstr(obd_jobid_name, "%j", joblen))
 713                         rc = jobid_get_from_cache(jobid, joblen);
 714
 715                 /* fall back to jobid_node if jobid_var not in environment */
 716                 if (rc < 0) {
 717                         int rc2 = jobid_interpret_string(obd_jobid_name,
 718                                                          jobid, joblen);
 719                         if (!rc2)
 720                                 rc = 0;
 721                 }
 722         }
 723
 724         RETURN(rc);
 725 }
 726 EXPORT_SYMBOL(lustre_get_jobid);
 727
 728 /*
 729  * lustre_jobid_clear
 730  *
 731  * Search cache for JobID given by @find_jobid.
 732  * If any entries in the hash table match the value, they are removed
 733  */
 734 void lustre_jobid_clear(const char *find_jobid)
 735 {
 736         char jobid[LUSTRE_JOBID_SIZE];
 737         char *end;
 738
 739         if (jobid_hash == NULL)
 740                 return;
 741
 742         strlcpy(jobid, find_jobid, sizeof(jobid));
 743         /* trim \n off the end of the incoming jobid */
 744         end = strchr(jobid, '\n');
 745         if (end && *end == '\n')
 746                 *end = '\0';
 747
 748         CDEBUG(D_INFO, "Clearing Jobid: %s\n", jobid);
 749         cfs_hash_cond_del(jobid_hash, jobid_should_free_item, jobid);
 750
 751         CDEBUG(D_INFO, "%d items remain in jobID table\n",
 752                atomic_read(&jobid_hash->hs_count));
 753 }