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 #include <linux/uidgid.h>
  37 #include <linux/utsname.h>
  38
  39 #include <libcfs/libcfs.h>
  40 #include <obd_support.h>
  41 #include <obd_class.h>
  42 #include <lustre_net.h>
  43
  44 static struct cfs_hash *jobid_hash;
  45 static struct cfs_hash_ops jobid_hash_ops;
  46 spinlock_t jobid_hash_lock;
  47
  48 #define RESCAN_INTERVAL 30
  49 #define DELETE_INTERVAL 300
  50
  51 char obd_jobid_var[JOBSTATS_JOBID_VAR_MAX_LEN + 1] = JOBSTATS_DISABLE;
  52 char obd_jobid_name[LUSTRE_JOBID_SIZE] = "%e.%u";
  53
  54 /**
  55  * Structure to store a single PID->JobID mapping
  56  */
  57 struct jobid_pid_map {
  58         struct hlist_node       jp_hash;
  59         time64_t                jp_time;
  60         spinlock_t              jp_lock; /* protects jp_jobid */
  61         char                    jp_jobid[LUSTRE_JOBID_SIZE];
  62         unsigned int            jp_joblen;
  63         atomic_t                jp_refcount;
  64         pid_t                   jp_pid;
  65 };
  66
  67 /*
  68  * Jobid can be set for a session (see setsid(2)) by writing to
  69  * a sysfs file from any process in that session.
  70  * The jobids are stored in a hash table indexed by the relevant
  71  * struct pid.  We periodically look for entries where the pid has
  72  * no PIDTYPE_SID tasks any more, and prune them.  This happens within
  73  * 5 seconds of a jobid being added, and every 5 minutes when jobids exist,
  74  * but none are added.
  75  */
  76 #define JOBID_EXPEDITED_CLEAN (5)
  77 #define JOBID_BACKGROUND_CLEAN (5 * 60)
  78
  79 struct session_jobid {
  80         struct pid              *sj_session;
  81         struct rhash_head       sj_linkage;
  82         struct rcu_head         sj_rcu;
  83         char                    sj_jobid[1];
  84 };
  85
  86 static const struct rhashtable_params jobid_params = {
  87         .key_len        = sizeof(struct pid *),
  88         .key_offset     = offsetof(struct session_jobid, sj_session),
  89         .head_offset    = offsetof(struct session_jobid, sj_linkage),
  90 };
  91
  92 static struct rhashtable session_jobids;
  93
  94 /*
  95  * jobid_current must be called with rcu_read_lock held.
  96  * if it returns non-NULL, the string can only be used
  97  * until rcu_read_unlock is called.
  98  */
  99 char *jobid_current(void)
 100 {
 101         struct pid *sid = task_session(current);
 102         struct session_jobid *sj;
 103
 104         sj = rhashtable_lookup_fast(&session_jobids, &sid, jobid_params);
 105         if (sj)
 106                 return sj->sj_jobid;
 107         return NULL;
 108 }
 109
 110 static void jobid_prune_expedite(void);
 111 /*
 112  * jobid_set_current will try to add a new entry
 113  * to the table.  If one exists with the same key, the
 114  * jobid will be replaced
 115  */
 116 int jobid_set_current(char *jobid)
 117 {
 118         struct pid *sid;
 119         struct session_jobid *sj, *origsj;
 120         int ret;
 121         int len = strlen(jobid);
 122
 123         sj = kmalloc(sizeof(*sj) + len, GFP_KERNEL);
 124         if (!sj)
 125                 return -ENOMEM;
 126         rcu_read_lock();
 127         sid = task_session(current);
 128         sj->sj_session = get_pid(sid);
 129         strncpy(sj->sj_jobid, jobid, len+1);
 130         origsj = rhashtable_lookup_get_insert_fast(&session_jobids,
 131                                                    &sj->sj_linkage,
 132                                                    jobid_params);
 133         if (origsj == NULL) {
 134                 /* successful insert */
 135                 rcu_read_unlock();
 136                 jobid_prune_expedite();
 137                 return 0;
 138         }
 139
 140         if (IS_ERR(origsj)) {
 141                 put_pid(sj->sj_session);
 142                 kfree(sj);
 143                 rcu_read_unlock();
 144                 return PTR_ERR(origsj);
 145         }
 146         ret = rhashtable_replace_fast(&session_jobids,
 147                                       &origsj->sj_linkage,
 148                                       &sj->sj_linkage,
 149                                       jobid_params);
 150         if (ret) {
 151                 put_pid(sj->sj_session);
 152                 kfree(sj);
 153                 rcu_read_unlock();
 154                 return ret;
 155         }
 156         put_pid(origsj->sj_session);
 157         rcu_read_unlock();
 158         kfree_rcu(origsj, sj_rcu);
 159         jobid_prune_expedite();
 160
 161         return 0;
 162 }
 163
 164 static void jobid_free(void *vsj, void *arg)
 165 {
 166         struct session_jobid *sj = vsj;
 167
 168         put_pid(sj->sj_session);
 169         kfree(sj);
 170 }
 171
 172 static void jobid_prune(struct work_struct *work);
 173 static DECLARE_DELAYED_WORK(jobid_prune_work, jobid_prune);
 174 static int jobid_prune_expedited;
 175 static void jobid_prune(struct work_struct *work)
 176 {
 177         int remaining = 0;
 178         struct rhashtable_iter iter;
 179         struct session_jobid *sj;
 180
 181         jobid_prune_expedited = 0;
 182         rhashtable_walk_enter(&session_jobids, &iter);
 183         rhashtable_walk_start(&iter);
 184         while ((sj = rhashtable_walk_next(&iter)) != NULL) {
 185                 if (!hlist_empty(&sj->sj_session->tasks[PIDTYPE_SID])) {
 186                         remaining++;
 187                         continue;
 188                 }
 189                 if (rhashtable_remove_fast(&session_jobids,
 190                                            &sj->sj_linkage,
 191                                            jobid_params) == 0) {
 192                         put_pid(sj->sj_session);
 193                         kfree_rcu(sj, sj_rcu);
 194                 }
 195         }
 196         rhashtable_walk_stop(&iter);
 197         rhashtable_walk_exit(&iter);
 198         if (remaining)
 199                 schedule_delayed_work(&jobid_prune_work,
 200                                       cfs_time_seconds(JOBID_BACKGROUND_CLEAN));
 201 }
 202
 203 static void jobid_prune_expedite(void)
 204 {
 205         if (!jobid_prune_expedited) {
 206                 jobid_prune_expedited = 1;
 207                 mod_delayed_work(system_wq, &jobid_prune_work,
 208                                  cfs_time_seconds(JOBID_EXPEDITED_CLEAN));
 209         }
 210 }
 211
 212 static int cfs_access_process_vm(struct task_struct *tsk,
 213                                  struct mm_struct *mm,
 214                                  unsigned long addr,
 215                                  void *buf, int len, int write)
 216 {
 217         /* Just copied from kernel for the kernels which doesn't
 218          * have access_process_vm() exported
 219          */
 220         struct vm_area_struct *vma;
 221         struct page *page;
 222         void *old_buf = buf;
 223
 224         /* Avoid deadlocks on mmap_sem if called from sys_mmap_pgoff(),
 225          * which is already holding mmap_sem for writes.  If some other
 226          * thread gets the write lock in the meantime, this thread will
 227          * block, but at least it won't deadlock on itself.  LU-1735
 228          */
 229         if (!mmap_read_trylock(mm))
 230                 return -EDEADLK;
 231
 232         /* ignore errors, just check how much was successfully transferred */
 233         while (len) {
 234                 int bytes, rc, offset;
 235                 void *maddr;
 236
 237 #if defined(HAVE_GET_USER_PAGES_GUP_FLAGS)
 238                 rc = get_user_pages(addr, 1, write ? FOLL_WRITE : 0, &page,
 239                                     &vma);
 240 #elif defined(HAVE_GET_USER_PAGES_6ARG)
 241                 rc = get_user_pages(addr, 1, write, 1, &page, &vma);
 242 #else
 243                 rc = get_user_pages(tsk, mm, addr, 1, write, 1, &page, &vma);
 244 #endif
 245                 if (rc <= 0)
 246                         break;
 247
 248                 bytes = len;
 249                 offset = addr & (PAGE_SIZE-1);
 250                 if (bytes > PAGE_SIZE-offset)
 251                         bytes = PAGE_SIZE-offset;
 252
 253                 maddr = kmap(page);
 254                 if (write) {
 255                         copy_to_user_page(vma, page, addr,
 256                                           maddr + offset, buf, bytes);
 257                         set_page_dirty_lock(page);
 258                 } else {
 259                         copy_from_user_page(vma, page, addr,
 260                                             buf, maddr + offset, bytes);
 261                 }
 262                 kunmap(page);
 263                 put_page(page);
 264                 len -= bytes;
 265                 buf += bytes;
 266                 addr += bytes;
 267         }
 268         mmap_read_unlock(mm);
 269
 270         return buf - old_buf;
 271 }
 272
 273 /* Read the environment variable of current process specified by @key. */
 274 static int cfs_get_environ(const char *key, char *value, int *val_len)
 275 {
 276         struct mm_struct *mm;
 277         char *buffer;
 278         int buf_len = PAGE_SIZE;
 279         int key_len = strlen(key);
 280         unsigned long addr;
 281         int rc;
 282         bool skip = false;
 283
 284         ENTRY;
 285         buffer = kmalloc(buf_len, GFP_USER);
 286         if (!buffer)
 287                 RETURN(-ENOMEM);
 288
 289         mm = get_task_mm(current);
 290         if (!mm) {
 291                 kfree(buffer);
 292                 RETURN(-EINVAL);
 293         }
 294
 295         addr = mm->env_start;
 296         while (addr < mm->env_end) {
 297                 int this_len, retval, scan_len;
 298                 char *env_start, *env_end;
 299
 300                 memset(buffer, 0, buf_len);
 301
 302                 this_len = min_t(int, mm->env_end - addr, buf_len);
 303                 retval = cfs_access_process_vm(current, mm, addr, buffer,
 304                                                this_len, 0);
 305                 if (retval < 0)
 306                         GOTO(out, rc = retval);
 307                 else if (retval != this_len)
 308                         break;
 309
 310                 addr += retval;
 311
 312                 /* Parse the buffer to find out the specified key/value pair.
 313                  * The "key=value" entries are separated by '\0'.
 314                  */
 315                 env_start = buffer;
 316                 scan_len = this_len;
 317                 while (scan_len) {
 318                         char *entry;
 319                         int entry_len;
 320
 321                         env_end = memscan(env_start, '\0', scan_len);
 322                         LASSERT(env_end >= env_start &&
 323                                 env_end <= env_start + scan_len);
 324
 325                         /* The last entry of this buffer cross the buffer
 326                          * boundary, reread it in next cycle.
 327                          */
 328                         if (unlikely(env_end - env_start == scan_len)) {
 329                                 /* Just skip the entry larger than page size,
 330                                  * it can't be jobID env variable.
 331                                  */
 332                                 if (unlikely(scan_len == this_len))
 333                                         skip = true;
 334                                 else
 335                                         addr -= scan_len;
 336                                 break;
 337                         } else if (unlikely(skip)) {
 338                                 skip = false;
 339                                 goto skip;
 340                         }
 341                         entry = env_start;
 342                         entry_len = env_end - env_start;
 343                         CDEBUG(D_INFO, "key: %s, entry: %s\n", key, entry);
 344
 345                         /* Key length + length of '=' */
 346                         if (entry_len > key_len + 1 &&
 347                             entry[key_len] == '='  &&
 348                             !memcmp(entry, key, key_len)) {
 349                                 entry += key_len + 1;
 350                                 entry_len -= key_len + 1;
 351
 352                                 /* The 'value' buffer passed in is too small.
 353                                  * Copy what fits, but return -EOVERFLOW.
 354                                  */
 355                                 if (entry_len >= *val_len) {
 356                                         memcpy(value, entry, *val_len);
 357                                         value[*val_len - 1] = 0;
 358                                         GOTO(out, rc = -EOVERFLOW);
 359                                 }
 360
 361                                 memcpy(value, entry, entry_len);
 362                                 *val_len = entry_len;
 363                                 GOTO(out, rc = 0);
 364                         }
 365 skip:
 366                         scan_len -= (env_end - env_start + 1);
 367                         env_start = env_end + 1;
 368                 }
 369         }
 370         GOTO(out, rc = -ENOENT);
 371
 372 out:
 373         mmput(mm);
 374         kfree((void *)buffer);
 375         return rc;
 376 }
 377
 378 /*
 379  * Get jobid of current process by reading the environment variable
 380  * stored in between the "env_start" & "env_end" of task struct.
 381  *
 382  * If some job scheduler doesn't store jobid in the "env_start/end",
 383  * then an upcall could be issued here to get the jobid by utilizing
 384  * the userspace tools/API. Then, the jobid must be cached.
 385  */
 386 int jobid_get_from_environ(char *jobid_var, char *jobid, int *jobid_len)
 387 {
 388         int rc;
 389
 390         rc = cfs_get_environ(jobid_var, jobid, jobid_len);
 391         if (!rc)
 392                 goto out;
 393
 394         if (rc == -EOVERFLOW) {
 395                 /* For the PBS_JOBID and LOADL_STEP_ID keys (which are
 396                  * variable length strings instead of just numbers), it
 397                  * might make sense to keep the unique parts for JobID,
 398                  * instead of just returning an error.  That means a
 399                  * larger temp buffer for cfs_get_environ(), then
 400                  * truncating the string at some separator to fit into
 401                  * the specified jobid_len.  Fix later if needed. */
 402                 static ktime_t printed;
 403
 404                 if (unlikely(ktime_to_ns(printed) == 0 ||
 405                              ktime_after(ktime_get(),
 406                                          ktime_add_ns(printed,
 407                                              3600ULL * 24 * NSEC_PER_SEC)))) {
 408                         LCONSOLE_WARN("jobid: '%s' value too large (%d)\n",
 409                                       obd_jobid_var, *jobid_len);
 410                         printed = ktime_get();
 411                 }
 412
 413                 rc = 0;
 414         } else {
 415                 CDEBUG_LIMIT((rc == -ENOENT || rc == -EINVAL ||
 416                               rc == -EDEADLK) ? D_INFO : D_ERROR,
 417                              "jobid: get '%s' failed: rc = %d\n",
 418                              obd_jobid_var, rc);
 419         }
 420
 421 out:
 422         return rc;
 423 }
 424
 425 /*
 426  * jobid_should_free_item
 427  *
 428  * Each item is checked to see if it should be released
 429  * Removed from hash table by caller
 430  * Actually freed in jobid_put_locked
 431  *
 432  * Returns 1 if item is to be freed, 0 if it is to be kept
 433  */
 434
 435 static int jobid_should_free_item(void *obj, void *data)
 436 {
 437         char *jobid = data;
 438         struct jobid_pid_map *pidmap = obj;
 439         int rc = 0;
 440
 441         if (obj == NULL)
 442                 return 0;
 443
 444         if (jobid == NULL) {
 445                 WARN_ON_ONCE(atomic_read(&pidmap->jp_refcount) != 1);
 446                 return 1;
 447         }
 448
 449         spin_lock(&pidmap->jp_lock);
 450         /* prevent newly inserted items from deleting */
 451         if (jobid[0] == '\0' && atomic_read(&pidmap->jp_refcount) == 1)
 452                 rc = 1;
 453         else if (ktime_get_real_seconds() - pidmap->jp_time > DELETE_INTERVAL)
 454                 rc = 1;
 455         else if (strcmp(pidmap->jp_jobid, jobid) == 0)
 456                 rc = 1;
 457         spin_unlock(&pidmap->jp_lock);
 458
 459         return rc;
 460 }
 461
 462 /*
 463  * jobid_name_is_valid
 464  *
 465  * Checks if the jobid is a Lustre process
 466  *
 467  * Returns true if jobid is valid
 468  * Returns false if jobid looks like it's a Lustre process
 469  */
 470 static bool jobid_name_is_valid(char *jobid)
 471 {
 472         const char *const lustre_reserved[] = { "ll_ping", "ptlrpc",
 473                                                 "ldlm", "ll_sa", NULL };
 474         int i;
 475
 476         if (jobid[0] == '\0')
 477                 return false;
 478
 479         for (i = 0; lustre_reserved[i] != NULL; i++) {
 480                 if (strncmp(jobid, lustre_reserved[i],
 481                             strlen(lustre_reserved[i])) == 0)
 482                         return false;
 483         }
 484         return true;
 485 }
 486
 487 /*
 488  * jobid_get_from_cache()
 489  *
 490  * Returns contents of jobid_var from process environment for current PID,
 491  * or from the per-session jobid table.
 492  * Values fetch from process environment will be cached for some time to avoid
 493  * the overhead of scanning the environment.
 494  *
 495  * Return: -ENOMEM if allocating a new pidmap fails
 496  *         -ENOENT if no entry could be found
 497  *         +ve string length for success (something was returned in jobid)
 498  */
 499 static int jobid_get_from_cache(char *jobid, size_t joblen)
 500 {
 501         static time64_t last_expire;
 502         bool expire_cache = false;
 503         pid_t pid = current->pid;
 504         struct jobid_pid_map *pidmap = NULL;
 505         time64_t now = ktime_get_real_seconds();
 506         int rc = 0;
 507         ENTRY;
 508
 509         if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0) {
 510                 char *jid;
 511
 512                 rcu_read_lock();
 513                 jid = jobid_current();
 514                 if (jid) {
 515                         strlcpy(jobid, jid, joblen);
 516                         joblen = strlen(jobid);
 517                 } else {
 518                         rc = -ENOENT;
 519                 }
 520                 rcu_read_unlock();
 521                 GOTO(out, rc);
 522         }
 523
 524         LASSERT(jobid_hash != NULL);
 525
 526         /* scan hash periodically to remove old PID entries from cache */
 527         spin_lock(&jobid_hash_lock);
 528         if (unlikely(last_expire + DELETE_INTERVAL <= now)) {
 529                 expire_cache = true;
 530                 last_expire = now;
 531         }
 532         spin_unlock(&jobid_hash_lock);
 533
 534         if (expire_cache)
 535                 cfs_hash_cond_del(jobid_hash, jobid_should_free_item,
 536                                   "intentionally_bad_jobid");
 537
 538         /* first try to find PID in the hash and use that value */
 539         pidmap = cfs_hash_lookup(jobid_hash, &pid);
 540         if (pidmap == NULL) {
 541                 struct jobid_pid_map *pidmap2;
 542
 543                 OBD_ALLOC_PTR(pidmap);
 544                 if (pidmap == NULL)
 545                         GOTO(out, rc = -ENOMEM);
 546
 547                 pidmap->jp_pid = pid;
 548                 pidmap->jp_time = 0;
 549                 pidmap->jp_jobid[0] = '\0';
 550                 spin_lock_init(&pidmap->jp_lock);
 551                 INIT_HLIST_NODE(&pidmap->jp_hash);
 552                 /*
 553                  * @pidmap might be reclaimed just after it is added into
 554                  * hash list, init @jp_refcount as 1 to make sure memory
 555                  * could be not freed during access.
 556                  */
 557                 atomic_set(&pidmap->jp_refcount, 1);
 558
 559                 /*
 560                  * Add the newly created map to the hash, on key collision we
 561                  * lost a racing addition and must destroy our newly allocated
 562                  * map.  The object which exists in the hash will be returned.
 563                  */
 564                 pidmap2 = cfs_hash_findadd_unique(jobid_hash, &pid,
 565                                                   &pidmap->jp_hash);
 566                 if (unlikely(pidmap != pidmap2)) {
 567                         CDEBUG(D_INFO, "jobid: duplicate found for PID=%u\n",
 568                                pid);
 569                         OBD_FREE_PTR(pidmap);
 570                         pidmap = pidmap2;
 571                 }
 572         }
 573
 574         /*
 575          * If pidmap is old (this is always true for new entries) refresh it.
 576          * If obd_jobid_var is not found, cache empty entry and try again
 577          * later, to avoid repeat lookups for PID if obd_jobid_var missing.
 578          */
 579         spin_lock(&pidmap->jp_lock);
 580         if (pidmap->jp_time + RESCAN_INTERVAL <= now) {
 581                 char env_jobid[LUSTRE_JOBID_SIZE] = "";
 582                 int env_len = sizeof(env_jobid);
 583
 584                 pidmap->jp_time = now;
 585
 586                 spin_unlock(&pidmap->jp_lock);
 587                 rc = jobid_get_from_environ(obd_jobid_var, env_jobid, &env_len);
 588
 589                 CDEBUG(D_INFO, "jobid: PID mapping established: %d->%s\n",
 590                        pidmap->jp_pid, env_jobid);
 591                 spin_lock(&pidmap->jp_lock);
 592                 if (!rc) {
 593                         pidmap->jp_joblen = env_len;
 594                         strlcpy(pidmap->jp_jobid, env_jobid,
 595                                 sizeof(pidmap->jp_jobid));
 596                         rc = 0;
 597                 } else if (rc == -ENOENT) {
 598                         /* It might have been deleted, clear out old entry */
 599                         pidmap->jp_joblen = 0;
 600                         pidmap->jp_jobid[0] = '\0';
 601                 }
 602         }
 603
 604         /*
 605          * Regardless of how pidmap was found, if it contains a valid entry
 606          * use that for now.  If there was a technical error (e.g. -ENOMEM)
 607          * use the old cached value until it can be looked up again properly.
 608          * If a cached missing entry was found, return -ENOENT.
 609          */
 610         if (pidmap->jp_joblen) {
 611                 strlcpy(jobid, pidmap->jp_jobid, joblen);
 612                 joblen = pidmap->jp_joblen;
 613                 rc = 0;
 614         } else if (!rc) {
 615                 rc = -ENOENT;
 616         }
 617         spin_unlock(&pidmap->jp_lock);
 618
 619         cfs_hash_put(jobid_hash, &pidmap->jp_hash);
 620
 621         EXIT;
 622 out:
 623         return rc < 0 ? rc : joblen;
 624 }
 625
 626 /*
 627  * jobid_interpret_string()
 628  *
 629  * Interpret the jobfmt string to expand specified fields, like coredumps do:
 630  *   %e = executable
 631  *   %g = gid
 632  *   %h = hostname
 633  *   %H = short hostname
 634  *   %j = jobid from environment
 635  *   %p = pid
 636  *   %u = uid
 637  *
 638  * Unknown escape strings are dropped.  Other characters are copied through,
 639  * excluding whitespace (to avoid making jobid parsing difficult).
 640  *
 641  * Return: -EOVERFLOW if the expanded string does not fit within @joblen
 642  *         0 for success
 643  */
 644 static int jobid_interpret_string(const char *jobfmt, char *jobid,
 645                                   ssize_t joblen)
 646 {
 647         char c;
 648
 649         while ((c = *jobfmt++) && joblen > 1) {
 650                 char f, *p;
 651                 int l;
 652
 653                 if (isspace(c)) /* Don't allow embedded spaces */
 654                         continue;
 655
 656                 if (c != '%') {
 657                         *jobid = c;
 658                         joblen--;
 659                         jobid++;
 660                         *jobid = '\0';
 661                         continue;
 662                 }
 663
 664                 switch ((f = *jobfmt++)) {
 665                 case 'e': /* executable name */
 666                         l = snprintf(jobid, joblen, "%s", current->comm);
 667                         break;
 668                 case 'g': /* group ID */
 669                         l = snprintf(jobid, joblen, "%u",
 670                                      from_kgid(&init_user_ns, current_fsgid()));
 671                         break;
 672                 case 'h': /* hostname */
 673                         l = snprintf(jobid, joblen, "%s",
 674                                      init_utsname()->nodename);
 675                         break;
 676                 case 'H': /* short hostname. Cut at first dot */
 677                         l = snprintf(jobid, joblen, "%s",
 678                                      init_utsname()->nodename);
 679                         p = strnchr(jobid, joblen, '.');
 680                         if (p) {
 681                                 *p = '\0';
 682                                 l = p - jobid;
 683                         }
 684                         break;
 685                 case 'j': /* jobid stored in process environment */
 686                         l = jobid_get_from_cache(jobid, joblen);
 687                         if (l < 0)
 688                                 l = 0;
 689                         break;
 690                 case 'p': /* process ID */
 691                         l = snprintf(jobid, joblen, "%u", current->pid);
 692                         break;
 693                 case 'u': /* user ID */
 694                         l = snprintf(jobid, joblen, "%u",
 695                                      from_kuid(&init_user_ns, current_fsuid()));
 696                         break;
 697                 case '\0': /* '%' at end of format string */
 698                         l = 0;
 699                         goto out;
 700                 default: /* drop unknown %x format strings */
 701                         l = 0;
 702                         break;
 703                 }
 704                 jobid += l;
 705                 joblen -= l;
 706         }
 707         /*
 708          * This points at the end of the buffer, so long as jobid is always
 709          * incremented the same amount as joblen is decremented.
 710          */
 711 out:
 712         jobid[joblen - 1] = '\0';
 713
 714         return joblen < 0 ? -EOVERFLOW : 0;
 715 }
 716
 717 /*
 718  * Hash initialization, copied from server-side job stats bucket sizes
 719  */
 720 #define HASH_JOBID_BKT_BITS 5
 721 #define HASH_JOBID_CUR_BITS 7
 722 #define HASH_JOBID_MAX_BITS 12
 723
 724 int jobid_cache_init(void)
 725 {
 726         int rc = 0;
 727         ENTRY;
 728
 729         if (jobid_hash)
 730                 return 0;
 731
 732         spin_lock_init(&jobid_hash_lock);
 733         jobid_hash = cfs_hash_create("JOBID_HASH", HASH_JOBID_CUR_BITS,
 734                                      HASH_JOBID_MAX_BITS, HASH_JOBID_BKT_BITS,
 735                                      0, CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
 736                                      &jobid_hash_ops, CFS_HASH_DEFAULT);
 737         if (!jobid_hash) {
 738                 rc = -ENOMEM;
 739         } else {
 740                 rc = rhashtable_init(&session_jobids, &jobid_params);
 741                 if (rc) {
 742                         cfs_hash_putref(jobid_hash);
 743                         jobid_hash = NULL;
 744                 }
 745         }
 746
 747         RETURN(rc);
 748 }
 749 EXPORT_SYMBOL(jobid_cache_init);
 750
 751 void jobid_cache_fini(void)
 752 {
 753         struct cfs_hash *tmp_hash;
 754         ENTRY;
 755
 756         spin_lock(&jobid_hash_lock);
 757         tmp_hash = jobid_hash;
 758         jobid_hash = NULL;
 759         spin_unlock(&jobid_hash_lock);
 760
 761         cancel_delayed_work_sync(&jobid_prune_work);
 762
 763         if (tmp_hash != NULL) {
 764                 cfs_hash_cond_del(tmp_hash, jobid_should_free_item, NULL);
 765                 cfs_hash_putref(tmp_hash);
 766
 767                 rhashtable_free_and_destroy(&session_jobids, jobid_free, NULL);
 768         }
 769
 770
 771         EXIT;
 772 }
 773 EXPORT_SYMBOL(jobid_cache_fini);
 774
 775 /*
 776  * Hash operations for pid<->jobid
 777  */
 778 static unsigned jobid_hashfn(struct cfs_hash *hs, const void *key,
 779                              unsigned mask)
 780 {
 781         return cfs_hash_djb2_hash(key, sizeof(pid_t), mask);
 782 }
 783
 784 static void *jobid_key(struct hlist_node *hnode)
 785 {
 786         struct jobid_pid_map *pidmap;
 787
 788         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 789         return &pidmap->jp_pid;
 790 }
 791
 792 static int jobid_keycmp(const void *key, struct hlist_node *hnode)
 793 {
 794         const pid_t *pid_key1;
 795         const pid_t *pid_key2;
 796
 797         LASSERT(key != NULL);
 798         pid_key1 = (pid_t *)key;
 799         pid_key2 = (pid_t *)jobid_key(hnode);
 800
 801         return *pid_key1 == *pid_key2;
 802 }
 803
 804 static void *jobid_object(struct hlist_node *hnode)
 805 {
 806         return hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 807 }
 808
 809 static void jobid_get(struct cfs_hash *hs, struct hlist_node *hnode)
 810 {
 811         struct jobid_pid_map *pidmap;
 812
 813         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 814
 815         atomic_inc(&pidmap->jp_refcount);
 816 }
 817
 818 static void jobid_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
 819 {
 820         struct jobid_pid_map *pidmap;
 821
 822         if (hnode == NULL)
 823                 return;
 824
 825         pidmap = hlist_entry(hnode, struct jobid_pid_map, jp_hash);
 826         LASSERT(atomic_read(&pidmap->jp_refcount) > 0);
 827         if (atomic_dec_and_test(&pidmap->jp_refcount)) {
 828                 CDEBUG(D_INFO, "Freeing: %d->%s\n",
 829                        pidmap->jp_pid, pidmap->jp_jobid);
 830
 831                 OBD_FREE_PTR(pidmap);
 832         }
 833 }
 834
 835 static struct cfs_hash_ops jobid_hash_ops = {
 836         .hs_hash        = jobid_hashfn,
 837         .hs_keycmp      = jobid_keycmp,
 838         .hs_key         = jobid_key,
 839         .hs_object      = jobid_object,
 840         .hs_get         = jobid_get,
 841         .hs_put         = jobid_put_locked,
 842         .hs_put_locked  = jobid_put_locked,
 843 };
 844
 845 /**
 846  * Generate the job identifier string for this process for tracking purposes.
 847  *
 848  * Fill in @jobid string based on the value of obd_jobid_var:
 849  * JOBSTATS_DISABLE:      none
 850  * JOBSTATS_NODELOCAL:    content of obd_jobid_name (jobid_interpret_string())
 851  * JOBSTATS_PROCNAME_UID: process name/UID
 852  * JOBSTATS_SESSION       per-session value set by
 853  *                            /sys/fs/lustre/jobid_this_session
 854  * anything else:         look up obd_jobid_var in the processes environment
 855  *
 856  * Return -ve error number, 0 on success.
 857  */
 858 int lustre_get_jobid(char *jobid, size_t joblen)
 859 {
 860         int rc = 0;
 861         ENTRY;
 862
 863         if (unlikely(joblen < 2)) {
 864                 if (joblen == 1)
 865                         jobid[0] = '\0';
 866                 RETURN(-EINVAL);
 867         }
 868
 869         if (strcmp(obd_jobid_var, JOBSTATS_DISABLE) == 0) {
 870                 /* Jobstats isn't enabled */
 871                 memset(jobid, 0, joblen);
 872         } else if (strcmp(obd_jobid_var, JOBSTATS_NODELOCAL) == 0) {
 873                 /* Whole node dedicated to single job */
 874                 rc = jobid_interpret_string(obd_jobid_name, jobid, joblen);
 875         } else if (strcmp(obd_jobid_var, JOBSTATS_PROCNAME_UID) == 0) {
 876                 rc = jobid_interpret_string("%e.%u", jobid, joblen);
 877         } else if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0 ||
 878                    jobid_name_is_valid(current->comm)) {
 879                 /*
 880                  * per-process jobid wanted, either from environment or from
 881                  * per-session setting.
 882                  * If obd_jobid_name contains "%j" or if getting the pre-process
 883                  * jobid directly fails, fall back to using obd_jobid_name.
 884                  */
 885                 rc = -EAGAIN;
 886                 if (!strnstr(obd_jobid_name, "%j", joblen))
 887                         rc = jobid_get_from_cache(jobid, joblen);
 888
 889                 /* fall back to jobid_node if jobid_var not available */
 890                 if (rc < 0) {
 891                         int rc2 = jobid_interpret_string(obd_jobid_name,
 892                                                          jobid, joblen);
 893                         if (!rc2)
 894                                 rc = 0;
 895                 }
 896         }
 897
 898         RETURN(rc);
 899 }
 900 EXPORT_SYMBOL(lustre_get_jobid);
 901
 902 /*
 903  * lustre_jobid_clear
 904  *
 905  * Search cache for JobID given by @find_jobid.
 906  * If any entries in the hash table match the value, they are removed
 907  */
 908 void lustre_jobid_clear(const char *find_jobid)
 909 {
 910         char jobid[LUSTRE_JOBID_SIZE];
 911         char *end;
 912
 913         if (jobid_hash == NULL)
 914                 return;
 915
 916         strlcpy(jobid, find_jobid, sizeof(jobid));
 917         /* trim \n off the end of the incoming jobid */
 918         end = strchr(jobid, '\n');
 919         if (end && *end == '\n')
 920                 *end = '\0';
 921
 922         CDEBUG(D_INFO, "Clearing Jobid: %s\n", jobid);
 923         cfs_hash_cond_del(jobid_hash, jobid_should_free_item, jobid);
 924
 925         CDEBUG(D_INFO, "%d items remain in jobID table\n",
 926                atomic_read(&jobid_hash->hs_count));
 927 }