kern_proc.c

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    1 /*
    2  * Copyright (c) 1982, 1986, 1989, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/kernel.h>
   33 #include <sys/sysctl.h>
   34 #include <sys/malloc.h>
   35 #include <sys/proc.h>
   36 #include <sys/vnode.h>
   37 #include <sys/jail.h>
   38 #include <sys/filedesc.h>
   39 #include <sys/tty.h>
   40 #include <sys/dsched.h>
   41 #include <sys/signalvar.h>
   42 #include <sys/spinlock.h>
   43 #include <sys/random.h>
   44 #include <vm/vm.h>
   45 #include <sys/lock.h>
   46 #include <vm/pmap.h>
   47 #include <vm/vm_map.h>
   48 #include <sys/user.h>
   49 #include <machine/smp.h>
   50 
   51 #include <sys/refcount.h>
   52 #include <sys/spinlock2.h>
   53 #include <sys/mplock2.h>
   54 
   55 /*
   56  * Hash table size must be a power of two and is not currently dynamically
   57  * sized.  There is a trade-off between the linear scans which must iterate
   58  * all HSIZE elements and the number of elements which might accumulate
   59  * within each hash chain.
   60  */
   61 #define ALLPROC_HSIZE   256
   62 #define ALLPROC_HMASK   (ALLPROC_HSIZE - 1)
   63 #define ALLPROC_HASH(pid)       (pid & ALLPROC_HMASK)
   64 #define PGRP_HASH(pid)  (pid & ALLPROC_HMASK)
   65 #define SESS_HASH(pid)  (pid & ALLPROC_HMASK)
   66 
   67 LIST_HEAD(pidhashhead, proc);
   68 
   69 static MALLOC_DEFINE(M_PGRP, "pgrp", "process group header");
   70 MALLOC_DEFINE(M_SESSION, "session", "session header");
   71 MALLOC_DEFINE(M_PROC, "proc", "Proc structures");
   72 MALLOC_DEFINE(M_LWP, "lwp", "lwp structures");
   73 MALLOC_DEFINE(M_SUBPROC, "subproc", "Proc sub-structures");
   74 
   75 int ps_showallprocs = 1;
   76 static int ps_showallthreads = 1;
   77 SYSCTL_INT(_security, OID_AUTO, ps_showallprocs, CTLFLAG_RW,
   78     &ps_showallprocs, 0,
   79     "Unprivileged processes can see processes with different UID/GID");
   80 SYSCTL_INT(_security, OID_AUTO, ps_showallthreads, CTLFLAG_RW,
   81     &ps_showallthreads, 0,
   82     "Unprivileged processes can see kernel threads");
   83 
   84 static void orphanpg(struct pgrp *pg);
   85 static void proc_makepid(struct proc *p, int random_offset);
   86 
   87 /*
   88  * Other process lists
   89  */
   90 static struct lwkt_token proc_tokens[ALLPROC_HSIZE];
   91 static struct proclist allprocs[ALLPROC_HSIZE]; /* locked by proc_tokens */
   92 static struct pgrplist allpgrps[ALLPROC_HSIZE]; /* locked by proc_tokens */
   93 static struct sesslist allsessn[ALLPROC_HSIZE]; /* locked by proc_tokens */
   94 
   95 /*
   96  * Random component to nextpid generation.  We mix in a random factor to make
   97  * it a little harder to predict.  We sanity check the modulus value to avoid
   98  * doing it in critical paths.  Don't let it be too small or we pointlessly
   99  * waste randomness entropy, and don't let it be impossibly large.  Using a
  100  * modulus that is too big causes a LOT more process table scans and slows
  101  * down fork processing as the pidchecked caching is defeated.
  102  */
  103 static int randompid = 0;
  104 
  105 /*
  106  * No requirements.
  107  */
  108 static int
  109 sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
  110 {
  111         int error, pid;
  112 
  113         pid = randompid;
  114         error = sysctl_handle_int(oidp, &pid, 0, req);
  115         if (error || !req->newptr)
  116                 return (error);
  117         if (pid < 0 || pid > PID_MAX - 100)     /* out of range */
  118                 pid = PID_MAX - 100;
  119         else if (pid < 2)                       /* NOP */
  120                 pid = 0;
  121         else if (pid < 100)                     /* Make it reasonable */
  122                 pid = 100;
  123         randompid = pid;
  124         return (error);
  125 }
  126 
  127 SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW,
  128             0, 0, sysctl_kern_randompid, "I", "Random PID modulus");
  129 
  130 /*
  131  * Initialize global process hashing structures.
  132  *
  133  * These functions are ONLY called from the low level boot code and do
  134  * not lock their operations.
  135  */
  136 void
  137 procinit(void)
  138 {
  139         u_long i;
  140 
  141         for (i = 0; i < ALLPROC_HSIZE; ++i) {
  142                 LIST_INIT(&allprocs[i]);
  143                 LIST_INIT(&allsessn[i]);
  144                 LIST_INIT(&allpgrps[i]);
  145                 lwkt_token_init(&proc_tokens[i], "allproc");
  146         }
  147         lwkt_init();
  148         uihashinit();
  149 }
  150 
  151 void
  152 procinsertinit(struct proc *p)
  153 {
  154         LIST_INSERT_HEAD(&allprocs[ALLPROC_HASH(p->p_pid)], p, p_list);
  155 }
  156 
  157 void
  158 pgrpinsertinit(struct pgrp *pg)
  159 {
  160         LIST_INSERT_HEAD(&allpgrps[ALLPROC_HASH(pg->pg_id)], pg, pg_list);
  161 }
  162 
  163 void
  164 sessinsertinit(struct session *sess)
  165 {
  166         LIST_INSERT_HEAD(&allsessn[ALLPROC_HASH(sess->s_sid)], sess, s_list);
  167 }
  168 
  169 /*
  170  * Process hold/release support functions.  Called via the PHOLD(),
  171  * PRELE(), and PSTALL() macros.
  172  *
  173  * p->p_lock is a simple hold count with a waiting interlock.  No wakeup()
  174  * is issued unless someone is actually waiting for the process.
  175  *
  176  * Most holds are short-term, allowing a process scan or other similar
  177  * operation to access a proc structure without it getting ripped out from
  178  * under us.  procfs and process-list sysctl ops also use the hold function
  179  * interlocked with various p_flags to keep the vmspace intact when reading
  180  * or writing a user process's address space.
  181  *
  182  * There are two situations where a hold count can be longer.  Exiting lwps
  183  * hold the process until the lwp is reaped, and the parent will hold the
  184  * child during vfork()/exec() sequences while the child is marked P_PPWAIT.
  185  *
  186  * The kernel waits for the hold count to drop to 0 (or 1 in some cases) at
  187  * various critical points in the fork/exec and exit paths before proceeding.
  188  */
  189 #define PLOCK_ZOMB      0x20000000
  190 #define PLOCK_WAITING   0x40000000
  191 #define PLOCK_MASK      0x1FFFFFFF
  192 
  193 void
  194 pstall(struct proc *p, const char *wmesg, int count)
  195 {
  196         int o;
  197         int n;
  198 
  199         for (;;) {
  200                 o = p->p_lock;
  201                 cpu_ccfence();
  202                 if ((o & PLOCK_MASK) <= count)
  203                         break;
  204                 n = o | PLOCK_WAITING;
  205                 tsleep_interlock(&p->p_lock, 0);
  206 
  207                 /*
  208                  * If someone is trying to single-step the process during
  209                  * an exec or an exit they can deadlock us because procfs
  210                  * sleeps with the process held.
  211                  */
  212                 if (p->p_stops) {
  213                         if (p->p_flags & P_INEXEC) {
  214                                 wakeup(&p->p_stype);
  215                         } else if (p->p_flags & P_POSTEXIT) {
  216                                 spin_lock(&p->p_spin);
  217                                 p->p_stops = 0;
  218                                 p->p_step = 0;
  219                                 spin_unlock(&p->p_spin);
  220                                 wakeup(&p->p_stype);
  221                         }
  222                 }
  223 
  224                 if (atomic_cmpset_int(&p->p_lock, o, n)) {
  225                         tsleep(&p->p_lock, PINTERLOCKED, wmesg, 0);
  226                 }
  227         }
  228 }
  229 
  230 void
  231 phold(struct proc *p)
  232 {
  233         atomic_add_int(&p->p_lock, 1);
  234 }
  235 
  236 /*
  237  * WARNING!  On last release (p) can become instantly invalid due to
  238  *           MP races.
  239  */
  240 void
  241 prele(struct proc *p)
  242 {
  243         int o;
  244         int n;
  245 
  246         /*
  247          * Fast path
  248          */
  249         if (atomic_cmpset_int(&p->p_lock, 1, 0))
  250                 return;
  251 
  252         /*
  253          * Slow path
  254          */
  255         for (;;) {
  256                 o = p->p_lock;
  257                 KKASSERT((o & PLOCK_MASK) > 0);
  258                 cpu_ccfence();
  259                 n = (o - 1) & ~PLOCK_WAITING;
  260                 if (atomic_cmpset_int(&p->p_lock, o, n)) {
  261                         if (o & PLOCK_WAITING)
  262                                 wakeup(&p->p_lock);
  263                         break;
  264                 }
  265         }
  266 }
  267 
  268 /*
  269  * Hold and flag serialized for zombie reaping purposes.
  270  *
  271  * This function will fail if it has to block, returning non-zero with
  272  * neither the flag set or the hold count bumped.  Note that we must block
  273  * without holding a ref, meaning that the caller must ensure that (p)
  274  * remains valid through some other interlock (typically on its parent
  275  * process's p_token).
  276  *
  277  * Zero is returned on success.  The hold count will be incremented and
  278  * the serialization flag acquired.  Note that serialization is only against
  279  * other pholdzomb() calls, not against phold() calls.
  280  */
  281 int
  282 pholdzomb(struct proc *p)
  283 {
  284         int o;
  285         int n;
  286 
  287         /*
  288          * Fast path
  289          */
  290         if (atomic_cmpset_int(&p->p_lock, 0, PLOCK_ZOMB | 1))
  291                 return(0);
  292 
  293         /*
  294          * Slow path
  295          */
  296         for (;;) {
  297                 o = p->p_lock;
  298                 cpu_ccfence();
  299                 if ((o & PLOCK_ZOMB) == 0) {
  300                         n = (o + 1) | PLOCK_ZOMB;
  301                         if (atomic_cmpset_int(&p->p_lock, o, n))
  302                                 return(0);
  303                 } else {
  304                         KKASSERT((o & PLOCK_MASK) > 0);
  305                         n = o | PLOCK_WAITING;
  306                         tsleep_interlock(&p->p_lock, 0);
  307                         if (atomic_cmpset_int(&p->p_lock, o, n)) {
  308                                 tsleep(&p->p_lock, PINTERLOCKED, "phldz", 0);
  309                                 /* (p) can be ripped out at this point */
  310                                 return(1);
  311                         }
  312                 }
  313         }
  314 }
  315 
  316 /*
  317  * Release PLOCK_ZOMB and the hold count, waking up any waiters.
  318  *
  319  * WARNING!  On last release (p) can become instantly invalid due to
  320  *           MP races.
  321  */
  322 void
  323 prelezomb(struct proc *p)
  324 {
  325         int o;
  326         int n;
  327 
  328         /*
  329          * Fast path
  330          */
  331         if (atomic_cmpset_int(&p->p_lock, PLOCK_ZOMB | 1, 0))
  332                 return;
  333 
  334         /*
  335          * Slow path
  336          */
  337         KKASSERT(p->p_lock & PLOCK_ZOMB);
  338         for (;;) {
  339                 o = p->p_lock;
  340                 KKASSERT((o & PLOCK_MASK) > 0);
  341                 cpu_ccfence();
  342                 n = (o - 1) & ~(PLOCK_ZOMB | PLOCK_WAITING);
  343                 if (atomic_cmpset_int(&p->p_lock, o, n)) {
  344                         if (o & PLOCK_WAITING)
  345                                 wakeup(&p->p_lock);
  346                         break;
  347                 }
  348         }
  349 }
  350 
  351 /*
  352  * Is p an inferior of the current process?
  353  *
  354  * No requirements.
  355  */
  356 int
  357 inferior(struct proc *p)
  358 {
  359         struct proc *p2;
  360 
  361         PHOLD(p);
  362         lwkt_gettoken_shared(&p->p_token);
  363         while (p != curproc) {
  364                 if (p->p_pid == 0) {
  365                         lwkt_reltoken(&p->p_token);
  366                         return (0);
  367                 }
  368                 p2 = p->p_pptr;
  369                 PHOLD(p2);
  370                 lwkt_reltoken(&p->p_token);
  371                 PRELE(p);
  372                 lwkt_gettoken_shared(&p2->p_token);
  373                 p = p2;
  374         }
  375         lwkt_reltoken(&p->p_token);
  376         PRELE(p);
  377 
  378         return (1);
  379 }
  380 
  381 /*
  382  * Locate a process by number.  The returned process will be referenced and
  383  * must be released with PRELE().
  384  *
  385  * No requirements.
  386  */
  387 struct proc *
  388 pfind(pid_t pid)
  389 {
  390         struct proc *p = curproc;
  391         int n;
  392 
  393         /*
  394          * Shortcut the current process
  395          */
  396         if (p && p->p_pid == pid) {
  397                 PHOLD(p);
  398                 return (p);
  399         }
  400 
  401         /*
  402          * Otherwise find it in the hash table.
  403          */
  404         n = ALLPROC_HASH(pid);
  405 
  406         lwkt_gettoken_shared(&proc_tokens[n]);
  407         LIST_FOREACH(p, &allprocs[n], p_list) {
  408                 if (p->p_stat == SZOMB)
  409                         continue;
  410                 if (p->p_pid == pid) {
  411                         PHOLD(p);
  412                         lwkt_reltoken(&proc_tokens[n]);
  413                         return (p);
  414                 }
  415         }
  416         lwkt_reltoken(&proc_tokens[n]);
  417 
  418         return (NULL);
  419 }
  420 
  421 /*
  422  * Locate a process by number.  The returned process is NOT referenced.
  423  * The result will not be stable and is typically only used to validate
  424  * against a process that the caller has in-hand.
  425  *
  426  * No requirements.
  427  */
  428 struct proc *
  429 pfindn(pid_t pid)
  430 {
  431         struct proc *p = curproc;
  432         int n;
  433 
  434         /*
  435          * Shortcut the current process
  436          */
  437         if (p && p->p_pid == pid)
  438                 return (p);
  439 
  440         /*
  441          * Otherwise find it in the hash table.
  442          */
  443         n = ALLPROC_HASH(pid);
  444 
  445         lwkt_gettoken_shared(&proc_tokens[n]);
  446         LIST_FOREACH(p, &allprocs[n], p_list) {
  447                 if (p->p_stat == SZOMB)
  448                         continue;
  449                 if (p->p_pid == pid) {
  450                         lwkt_reltoken(&proc_tokens[n]);
  451                         return (p);
  452                 }
  453         }
  454         lwkt_reltoken(&proc_tokens[n]);
  455 
  456         return (NULL);
  457 }
  458 
  459 /*
  460  * Locate a process on the zombie list.  Return a process or NULL.
  461  * The returned process will be referenced and the caller must release
  462  * it with PRELE().
  463  *
  464  * No other requirements.
  465  */
  466 struct proc *
  467 zpfind(pid_t pid)
  468 {
  469         struct proc *p = curproc;
  470         int n;
  471 
  472         /*
  473          * Shortcut the current process
  474          */
  475         if (p && p->p_pid == pid) {
  476                 PHOLD(p);
  477                 return (p);
  478         }
  479 
  480         /*
  481          * Otherwise find it in the hash table.
  482          */
  483         n = ALLPROC_HASH(pid);
  484 
  485         lwkt_gettoken_shared(&proc_tokens[n]);
  486         LIST_FOREACH(p, &allprocs[n], p_list) {
  487                 if (p->p_stat != SZOMB)
  488                         continue;
  489                 if (p->p_pid == pid) {
  490                         PHOLD(p);
  491                         lwkt_reltoken(&proc_tokens[n]);
  492                         return (p);
  493                 }
  494         }
  495         lwkt_reltoken(&proc_tokens[n]);
  496 
  497         return (NULL);
  498 }
  499 
  500 
  501 void
  502 pgref(struct pgrp *pgrp)
  503 {
  504         refcount_acquire(&pgrp->pg_refs);
  505 }
  506 
  507 void
  508 pgrel(struct pgrp *pgrp)
  509 {
  510         int count;
  511         int n;
  512 
  513         n = PGRP_HASH(pgrp->pg_id);
  514         for (;;) {
  515                 count = pgrp->pg_refs;
  516                 cpu_ccfence();
  517                 KKASSERT(count > 0);
  518                 if (count == 1) {
  519                         lwkt_gettoken(&proc_tokens[n]);
  520                         if (atomic_cmpset_int(&pgrp->pg_refs, 1, 0))
  521                                 break;
  522                         lwkt_reltoken(&proc_tokens[n]);
  523                         /* retry */
  524                 } else {
  525                         if (atomic_cmpset_int(&pgrp->pg_refs, count, count - 1))
  526                                 return;
  527                         /* retry */
  528                 }
  529         }
  530 
  531         /*
  532          * Successful 1->0 transition, pghash_spin is held.
  533          */
  534         LIST_REMOVE(pgrp, pg_list);
  535 
  536         /*
  537          * Reset any sigio structures pointing to us as a result of
  538          * F_SETOWN with our pgid.
  539          */
  540         funsetownlst(&pgrp->pg_sigiolst);
  541 
  542         if (pgrp->pg_session->s_ttyp != NULL &&
  543             pgrp->pg_session->s_ttyp->t_pgrp == pgrp) {
  544                 pgrp->pg_session->s_ttyp->t_pgrp = NULL;
  545         }
  546         lwkt_reltoken(&proc_tokens[n]);
  547 
  548         sess_rele(pgrp->pg_session);
  549         kfree(pgrp, M_PGRP);
  550 }
  551 
  552 /*
  553  * Locate a process group by number.  The returned process group will be
  554  * referenced w/pgref() and must be released with pgrel() (or assigned
  555  * somewhere if you wish to keep the reference).
  556  *
  557  * No requirements.
  558  */
  559 struct pgrp *
  560 pgfind(pid_t pgid)
  561 {
  562         struct pgrp *pgrp;
  563         int n;
  564 
  565         n = PGRP_HASH(pgid);
  566         lwkt_gettoken_shared(&proc_tokens[n]);
  567 
  568         LIST_FOREACH(pgrp, &allpgrps[n], pg_list) {
  569                 if (pgrp->pg_id == pgid) {
  570                         refcount_acquire(&pgrp->pg_refs);
  571                         lwkt_reltoken(&proc_tokens[n]);
  572                         return (pgrp);
  573                 }
  574         }
  575         lwkt_reltoken(&proc_tokens[n]);
  576         return (NULL);
  577 }
  578 
  579 /*
  580  * Move p to a new or existing process group (and session)
  581  *
  582  * No requirements.
  583  */
  584 int
  585 enterpgrp(struct proc *p, pid_t pgid, int mksess)
  586 {
  587         struct pgrp *pgrp;
  588         struct pgrp *opgrp;
  589         int error;
  590 
  591         pgrp = pgfind(pgid);
  592 
  593         KASSERT(pgrp == NULL || !mksess,
  594                 ("enterpgrp: setsid into non-empty pgrp"));
  595         KASSERT(!SESS_LEADER(p),
  596                 ("enterpgrp: session leader attempted setpgrp"));
  597 
  598         if (pgrp == NULL) {
  599                 pid_t savepid = p->p_pid;
  600                 struct proc *np;
  601                 int n;
  602 
  603                 /*
  604                  * new process group
  605                  */
  606                 KASSERT(p->p_pid == pgid,
  607                         ("enterpgrp: new pgrp and pid != pgid"));
  608                 pgrp = kmalloc(sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
  609                 pgrp->pg_id = pgid;
  610                 LIST_INIT(&pgrp->pg_members);
  611                 pgrp->pg_jobc = 0;
  612                 SLIST_INIT(&pgrp->pg_sigiolst);
  613                 lwkt_token_init(&pgrp->pg_token, "pgrp_token");
  614                 refcount_init(&pgrp->pg_refs, 1);
  615                 lockinit(&pgrp->pg_lock, "pgwt", 0, 0);
  616 
  617                 n = PGRP_HASH(pgid);
  618 
  619                 if ((np = pfindn(savepid)) == NULL || np != p) {
  620                         lwkt_reltoken(&proc_tokens[n]);
  621                         error = ESRCH;
  622                         kfree(pgrp, M_PGRP);
  623                         goto fatal;
  624                 }
  625 
  626                 lwkt_gettoken(&proc_tokens[n]);
  627                 if (mksess) {
  628                         struct session *sess;
  629 
  630                         /*
  631                          * new session
  632                          */
  633                         sess = kmalloc(sizeof(struct session), M_SESSION,
  634                                        M_WAITOK | M_ZERO);
  635                         lwkt_gettoken(&p->p_token);
  636                         sess->s_leader = p;
  637                         sess->s_sid = p->p_pid;
  638                         sess->s_count = 1;
  639                         sess->s_ttyvp = NULL;
  640                         sess->s_ttyp = NULL;
  641                         bcopy(p->p_session->s_login, sess->s_login,
  642                               sizeof(sess->s_login));
  643                         pgrp->pg_session = sess;
  644                         KASSERT(p == curproc,
  645                                 ("enterpgrp: mksession and p != curproc"));
  646                         p->p_flags &= ~P_CONTROLT;
  647                         LIST_INSERT_HEAD(&allsessn[n], sess, s_list);
  648                         lwkt_reltoken(&p->p_token);
  649                 } else {
  650                         lwkt_gettoken(&p->p_token);
  651                         pgrp->pg_session = p->p_session;
  652                         sess_hold(pgrp->pg_session);
  653                         lwkt_reltoken(&p->p_token);
  654                 }
  655                 LIST_INSERT_HEAD(&allpgrps[n], pgrp, pg_list);
  656 
  657                 lwkt_reltoken(&proc_tokens[n]);
  658         } else if (pgrp == p->p_pgrp) {
  659                 pgrel(pgrp);
  660                 goto done;
  661         } /* else pgfind() referenced the pgrp */
  662 
  663         lwkt_gettoken(&pgrp->pg_token);
  664         lwkt_gettoken(&p->p_token);
  665 
  666         /*
  667          * Replace p->p_pgrp, handling any races that occur.
  668          */
  669         while ((opgrp = p->p_pgrp) != NULL) {
  670                 pgref(opgrp);
  671                 lwkt_gettoken(&opgrp->pg_token);
  672                 if (opgrp != p->p_pgrp) {
  673                         lwkt_reltoken(&opgrp->pg_token);
  674                         pgrel(opgrp);
  675                         continue;
  676                 }
  677                 LIST_REMOVE(p, p_pglist);
  678                 break;
  679         }
  680         p->p_pgrp = pgrp;
  681         LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
  682 
  683         /*
  684          * Adjust eligibility of affected pgrps to participate in job control.
  685          * Increment eligibility counts before decrementing, otherwise we
  686          * could reach 0 spuriously during the first call.
  687          */
  688         fixjobc(p, pgrp, 1);
  689         if (opgrp) {
  690                 fixjobc(p, opgrp, 0);
  691                 lwkt_reltoken(&opgrp->pg_token);
  692                 pgrel(opgrp);   /* manual pgref */
  693                 pgrel(opgrp);   /* p->p_pgrp ref */
  694         }
  695         lwkt_reltoken(&p->p_token);
  696         lwkt_reltoken(&pgrp->pg_token);
  697 done:
  698         error = 0;
  699 fatal:
  700         return (error);
  701 }
  702 
  703 /*
  704  * Remove process from process group
  705  *
  706  * No requirements.
  707  */
  708 int
  709 leavepgrp(struct proc *p)
  710 {
  711         struct pgrp *pg = p->p_pgrp;
  712 
  713         lwkt_gettoken(&p->p_token);
  714         while ((pg = p->p_pgrp) != NULL) {
  715                 pgref(pg);
  716                 lwkt_gettoken(&pg->pg_token);
  717                 if (p->p_pgrp != pg) {
  718                         lwkt_reltoken(&pg->pg_token);
  719                         pgrel(pg);
  720                         continue;
  721                 }
  722                 p->p_pgrp = NULL;
  723                 LIST_REMOVE(p, p_pglist);
  724                 lwkt_reltoken(&pg->pg_token);
  725                 pgrel(pg);      /* manual pgref */
  726                 pgrel(pg);      /* p->p_pgrp ref */
  727                 break;
  728         }
  729         lwkt_reltoken(&p->p_token);
  730 
  731         return (0);
  732 }
  733 
  734 /*
  735  * Adjust the ref count on a session structure.  When the ref count falls to
  736  * zero the tty is disassociated from the session and the session structure
  737  * is freed.  Note that tty assocation is not itself ref-counted.
  738  *
  739  * No requirements.
  740  */
  741 void
  742 sess_hold(struct session *sp)
  743 {
  744         atomic_add_int(&sp->s_count, 1);
  745 }
  746 
  747 /*
  748  * No requirements.
  749  */
  750 void
  751 sess_rele(struct session *sess)
  752 {
  753         struct tty *tp;
  754         int count;
  755         int n;
  756 
  757         n = SESS_HASH(sess->s_sid);
  758         for (;;) {
  759                 count = sess->s_count;
  760                 cpu_ccfence();
  761                 KKASSERT(count > 0);
  762                 if (count == 1) {
  763                         lwkt_gettoken(&tty_token);
  764                         lwkt_gettoken(&proc_tokens[n]);
  765                         if (atomic_cmpset_int(&sess->s_count, 1, 0))
  766                                 break;
  767                         lwkt_reltoken(&proc_tokens[n]);
  768                         lwkt_reltoken(&tty_token);
  769                         /* retry */
  770                 } else {
  771                         if (atomic_cmpset_int(&sess->s_count, count, count - 1))
  772                                 return;
  773                         /* retry */
  774                 }
  775         }
  776 
  777         /*
  778          * Successful 1->0 transition and tty_token is held.
  779          */
  780         LIST_REMOVE(sess, s_list);
  781 
  782         if (sess->s_ttyp && sess->s_ttyp->t_session) {
  783 #ifdef TTY_DO_FULL_CLOSE
  784                 /* FULL CLOSE, see ttyclearsession() */
  785                 KKASSERT(sess->s_ttyp->t_session == sess);
  786                 sess->s_ttyp->t_session = NULL;
  787 #else
  788                 /* HALF CLOSE, see ttyclearsession() */
  789                 if (sess->s_ttyp->t_session == sess)
  790                         sess->s_ttyp->t_session = NULL;
  791 #endif
  792         }
  793         if ((tp = sess->s_ttyp) != NULL) {
  794                 sess->s_ttyp = NULL;
  795                 ttyunhold(tp);
  796         }
  797         lwkt_reltoken(&proc_tokens[n]);
  798         lwkt_reltoken(&tty_token);
  799 
  800         kfree(sess, M_SESSION);
  801 }
  802 
  803 /*
  804  * Adjust pgrp jobc counters when specified process changes process group.
  805  * We count the number of processes in each process group that "qualify"
  806  * the group for terminal job control (those with a parent in a different
  807  * process group of the same session).  If that count reaches zero, the
  808  * process group becomes orphaned.  Check both the specified process'
  809  * process group and that of its children.
  810  * entering == 0 => p is leaving specified group.
  811  * entering == 1 => p is entering specified group.
  812  *
  813  * No requirements.
  814  */
  815 void
  816 fixjobc(struct proc *p, struct pgrp *pgrp, int entering)
  817 {
  818         struct pgrp *hispgrp;
  819         struct session *mysession;
  820         struct proc *np;
  821 
  822         /*
  823          * Check p's parent to see whether p qualifies its own process
  824          * group; if so, adjust count for p's process group.
  825          */
  826         lwkt_gettoken(&p->p_token);     /* p_children scan */
  827         lwkt_gettoken(&pgrp->pg_token);
  828 
  829         mysession = pgrp->pg_session;
  830         if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
  831             hispgrp->pg_session == mysession) {
  832                 if (entering)
  833                         pgrp->pg_jobc++;
  834                 else if (--pgrp->pg_jobc == 0)
  835                         orphanpg(pgrp);
  836         }
  837 
  838         /*
  839          * Check this process' children to see whether they qualify
  840          * their process groups; if so, adjust counts for children's
  841          * process groups.
  842          */
  843         LIST_FOREACH(np, &p->p_children, p_sibling) {
  844                 PHOLD(np);
  845                 lwkt_gettoken(&np->p_token);
  846                 if ((hispgrp = np->p_pgrp) != pgrp &&
  847                     hispgrp->pg_session == mysession &&
  848                     np->p_stat != SZOMB) {
  849                         pgref(hispgrp);
  850                         lwkt_gettoken(&hispgrp->pg_token);
  851                         if (entering)
  852                                 hispgrp->pg_jobc++;
  853                         else if (--hispgrp->pg_jobc == 0)
  854                                 orphanpg(hispgrp);
  855                         lwkt_reltoken(&hispgrp->pg_token);
  856                         pgrel(hispgrp);
  857                 }
  858                 lwkt_reltoken(&np->p_token);
  859                 PRELE(np);
  860         }
  861         KKASSERT(pgrp->pg_refs > 0);
  862         lwkt_reltoken(&pgrp->pg_token);
  863         lwkt_reltoken(&p->p_token);
  864 }
  865 
  866 /*
  867  * A process group has become orphaned;
  868  * if there are any stopped processes in the group,
  869  * hang-up all process in that group.
  870  *
  871  * The caller must hold pg_token.
  872  */
  873 static void
  874 orphanpg(struct pgrp *pg)
  875 {
  876         struct proc *p;
  877 
  878         LIST_FOREACH(p, &pg->pg_members, p_pglist) {
  879                 if (p->p_stat == SSTOP) {
  880                         LIST_FOREACH(p, &pg->pg_members, p_pglist) {
  881                                 ksignal(p, SIGHUP);
  882                                 ksignal(p, SIGCONT);
  883                         }
  884                         return;
  885                 }
  886         }
  887 }
  888 
  889 /*
  890  * Add a new process to the allproc list and the PID hash.  This
  891  * also assigns a pid to the new process.
  892  *
  893  * No requirements.
  894  */
  895 void
  896 proc_add_allproc(struct proc *p)
  897 {
  898         int random_offset;
  899 
  900         if ((random_offset = randompid) != 0) {
  901                 read_random(&random_offset, sizeof(random_offset));
  902                 random_offset = (random_offset & 0x7FFFFFFF) % randompid;
  903         }
  904         proc_makepid(p, random_offset);
  905 }
  906 
  907 /*
  908  * Calculate a new process pid.  This function is integrated into
  909  * proc_add_allproc() to guarentee that the new pid is not reused before
  910  * the new process can be added to the allproc list.
  911  *
  912  * p_pid is assigned and the process is added to the allproc hash table
  913  */
  914 static
  915 void
  916 proc_makepid(struct proc *p, int random_offset)
  917 {
  918         static pid_t nextpid;   /* heuristic, allowed to race */
  919         struct pgrp *pg;
  920         struct proc *ps;
  921         struct session *sess;
  922         pid_t base;
  923         int n;
  924 
  925         /*
  926          * Calculate a hash index and find an unused process id within
  927          * the table, looping if we cannot find one.
  928          */
  929         if (random_offset)
  930                 atomic_add_int(&nextpid, random_offset);
  931 retry:
  932         base = atomic_fetchadd_int(&nextpid, 1) + 1;
  933         if (base >= PID_MAX) {
  934                 base = base % PID_MAX;
  935                 if (base < 100)
  936                         base += 100;
  937         }
  938         n = ALLPROC_HASH(base);
  939         lwkt_gettoken(&proc_tokens[n]);
  940 
  941         LIST_FOREACH(ps, &allprocs[n], p_list) {
  942                 if (ps->p_pid == base) {
  943                         base += ALLPROC_HSIZE;
  944                         if (base >= PID_MAX) {
  945                                 lwkt_reltoken(&proc_tokens[n]);
  946                                 goto retry;
  947                         }
  948                 }
  949         }
  950         LIST_FOREACH(pg, &allpgrps[n], pg_list) {
  951                 if (pg->pg_id == base) {
  952                         base += ALLPROC_HSIZE;
  953                         if (base >= PID_MAX) {
  954                                 lwkt_reltoken(&proc_tokens[n]);
  955                                 goto retry;
  956                         }
  957                 }
  958         }
  959         LIST_FOREACH(sess, &allsessn[n], s_list) {
  960                 if (sess->s_sid == base) {
  961                         base += ALLPROC_HSIZE;
  962                         if (base >= PID_MAX) {
  963                                 lwkt_reltoken(&proc_tokens[n]);
  964                                 goto retry;
  965                         }
  966                 }
  967         }
  968 
  969         /*
  970          * Assign the pid and insert the process.
  971          */
  972         p->p_pid = base;
  973         LIST_INSERT_HEAD(&allprocs[n], p, p_list);
  974         lwkt_reltoken(&proc_tokens[n]);
  975 }
  976 
  977 /*
  978  * Called from exit1 to place the process into a zombie state.
  979  * The process is removed from the pid hash and p_stat is set
  980  * to SZOMB.  Normal pfind[n]() calls will not find it any more.
  981  *
  982  * Caller must hold p->p_token.  We are required to wait until p_lock
  983  * becomes zero before we can manipulate the list, allowing allproc
  984  * scans to guarantee consistency during a list scan.
  985  */
  986 void
  987 proc_move_allproc_zombie(struct proc *p)
  988 {
  989         int n;
  990 
  991         n = ALLPROC_HASH(p->p_pid);
  992         PSTALL(p, "reap1", 0);
  993         lwkt_gettoken(&proc_tokens[n]);
  994 
  995         PSTALL(p, "reap1a", 0);
  996         p->p_stat = SZOMB;
  997 
  998         lwkt_reltoken(&proc_tokens[n]);
  999         dsched_exit_proc(p);
 1000 }
 1001 
 1002 /*
 1003  * This routine is called from kern_wait() and will remove the process
 1004  * from the zombie list and the sibling list.  This routine will block
 1005  * if someone has a lock on the proces (p_lock).
 1006  *
 1007  * Caller must hold p->p_token.  We are required to wait until p_lock
 1008  * becomes zero before we can manipulate the list, allowing allproc
 1009  * scans to guarantee consistency during a list scan.
 1010  */
 1011 void
 1012 proc_remove_zombie(struct proc *p)
 1013 {
 1014         int n;
 1015 
 1016         n = ALLPROC_HASH(p->p_pid);
 1017 
 1018         PSTALL(p, "reap2", 0);
 1019         lwkt_gettoken(&proc_tokens[n]);
 1020         PSTALL(p, "reap2a", 0);
 1021         LIST_REMOVE(p, p_list);         /* from remove master list */
 1022         LIST_REMOVE(p, p_sibling);      /* and from sibling list */
 1023         p->p_pptr = NULL;
 1024         lwkt_reltoken(&proc_tokens[n]);
 1025 }
 1026 
 1027 /*
 1028  * Handle various requirements prior to returning to usermode.  Called from
 1029  * platform trap and system call code.
 1030  */
 1031 void
 1032 lwpuserret(struct lwp *lp)
 1033 {
 1034         struct proc *p = lp->lwp_proc;
 1035 
 1036         if (lp->lwp_mpflags & LWP_MP_VNLRU) {
 1037                 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_VNLRU);
 1038                 allocvnode_gc();
 1039         }
 1040         if (lp->lwp_mpflags & LWP_MP_WEXIT) {
 1041                 lwkt_gettoken(&p->p_token);
 1042                 lwp_exit(0, NULL);
 1043                 lwkt_reltoken(&p->p_token);     /* NOT REACHED */
 1044         }
 1045 }
 1046 
 1047 /*
 1048  * Kernel threads run from user processes can also accumulate deferred
 1049  * actions which need to be acted upon.  Callers include:
 1050  *
 1051  * nfsd         - Can allocate lots of vnodes
 1052  */
 1053 void
 1054 lwpkthreaddeferred(void)
 1055 {
 1056         struct lwp *lp = curthread->td_lwp;
 1057 
 1058         if (lp) {
 1059                 if (lp->lwp_mpflags & LWP_MP_VNLRU) {
 1060                         atomic_clear_int(&lp->lwp_mpflags, LWP_MP_VNLRU);
 1061                         allocvnode_gc();
 1062                 }
 1063         }
 1064 }
 1065 
 1066 /*
 1067  * Scan all processes on the allproc list.  The process is automatically
 1068  * held for the callback.  A return value of -1 terminates the loop.
 1069  * Zombie procs are skipped.
 1070  *
 1071  * The callback is made with the process held and proc_token held.
 1072  *
 1073  * We limit the scan to the number of processes as-of the start of
 1074  * the scan so as not to get caught up in an endless loop if new processes
 1075  * are created more quickly than we can scan the old ones.  Add a little
 1076  * slop to try to catch edge cases since nprocs can race.
 1077  *
 1078  * No requirements.
 1079  */
 1080 void
 1081 allproc_scan(int (*callback)(struct proc *, void *), void *data)
 1082 {
 1083         int limit = nprocs + ncpus;
 1084         struct proc *p;
 1085         int r;
 1086         int n;
 1087 
 1088         /*
 1089          * proc_tokens[n] protects the allproc list and PHOLD() prevents the
 1090          * process from being removed from the allproc list or the zombproc
 1091          * list.
 1092          */
 1093         for (n = 0; n < ALLPROC_HSIZE; ++n) {
 1094                 if (LIST_FIRST(&allprocs[n]) == NULL)
 1095                         continue;
 1096                 lwkt_gettoken(&proc_tokens[n]);
 1097                 LIST_FOREACH(p, &allprocs[n], p_list) {
 1098                         if (p->p_stat == SZOMB)
 1099                                 continue;
 1100                         PHOLD(p);
 1101                         r = callback(p, data);
 1102                         PRELE(p);
 1103                         if (r < 0)
 1104                                 break;
 1105                         if (--limit < 0)
 1106                                 break;
 1107                 }
 1108                 lwkt_reltoken(&proc_tokens[n]);
 1109 
 1110                 /*
 1111                  * Check if asked to stop early
 1112                  */
 1113                 if (p)
 1114                         break;
 1115         }
 1116 }
 1117 
 1118 /*
 1119  * Scan all lwps of processes on the allproc list.  The lwp is automatically
 1120  * held for the callback.  A return value of -1 terminates the loop.
 1121  *
 1122  * The callback is made with the proces and lwp both held, and proc_token held.
 1123  *
 1124  * No requirements.
 1125  */
 1126 void
 1127 alllwp_scan(int (*callback)(struct lwp *, void *), void *data)
 1128 {
 1129         struct proc *p;
 1130         struct lwp *lp;
 1131         int r = 0;
 1132         int n;
 1133 
 1134         for (n = 0; n < ALLPROC_HSIZE; ++n) {
 1135                 if (LIST_FIRST(&allprocs[n]) == NULL)
 1136                         continue;
 1137                 lwkt_gettoken(&proc_tokens[n]);
 1138                 LIST_FOREACH(p, &allprocs[n], p_list) {
 1139                         if (p->p_stat == SZOMB)
 1140                                 continue;
 1141                         PHOLD(p);
 1142                         lwkt_gettoken(&p->p_token);
 1143                         FOREACH_LWP_IN_PROC(lp, p) {
 1144                                 LWPHOLD(lp);
 1145                                 r = callback(lp, data);
 1146                                 LWPRELE(lp);
 1147                         }
 1148                         lwkt_reltoken(&p->p_token);
 1149                         PRELE(p);
 1150                         if (r < 0)
 1151                                 break;
 1152                 }
 1153                 lwkt_reltoken(&proc_tokens[n]);
 1154 
 1155                 /*
 1156                  * Asked to exit early
 1157                  */
 1158                 if (p)
 1159                         break;
 1160         }
 1161 }
 1162 
 1163 /*
 1164  * Scan all processes on the zombproc list.  The process is automatically
 1165  * held for the callback.  A return value of -1 terminates the loop.
 1166  *
 1167  * No requirements.
 1168  * The callback is made with the proces held and proc_token held.
 1169  */
 1170 void
 1171 zombproc_scan(int (*callback)(struct proc *, void *), void *data)
 1172 {
 1173         struct proc *p;
 1174         int r;
 1175         int n;
 1176 
 1177         /*
 1178          * proc_tokens[n] protects the allproc list and PHOLD() prevents the
 1179          * process from being removed from the allproc list or the zombproc
 1180          * list.
 1181          */
 1182         for (n = 0; n < ALLPROC_HSIZE; ++n) {
 1183                 if (LIST_FIRST(&allprocs[n]) == NULL)
 1184                         continue;
 1185                 lwkt_gettoken(&proc_tokens[n]);
 1186                 LIST_FOREACH(p, &allprocs[n], p_list) {
 1187                         if (p->p_stat != SZOMB)
 1188                                 continue;
 1189                         PHOLD(p);
 1190                         r = callback(p, data);
 1191                         PRELE(p);
 1192                         if (r < 0)
 1193                                 break;
 1194                 }
 1195                 lwkt_reltoken(&proc_tokens[n]);
 1196 
 1197                 /*
 1198                  * Check if asked to stop early
 1199                  */
 1200                 if (p)
 1201                         break;
 1202         }
 1203 }
 1204 
 1205 #include "opt_ddb.h"
 1206 #ifdef DDB
 1207 #include <ddb/ddb.h>
 1208 
 1209 /*
 1210  * Debugging only
 1211  */
 1212 DB_SHOW_COMMAND(pgrpdump, pgrpdump)
 1213 {
 1214         struct pgrp *pgrp;
 1215         struct proc *p;
 1216         int i;
 1217 
 1218         for (i = 0; i < ALLPROC_HSIZE; ++i) {
 1219                 if (LIST_EMPTY(&allpgrps[i]))
 1220                         continue;
 1221                 kprintf("\tindx %d\n", i);
 1222                 LIST_FOREACH(pgrp, &allpgrps[i], pg_list) {
 1223                         kprintf("\tpgrp %p, pgid %ld, sess %p, "
 1224                                 "sesscnt %d, mem %p\n",
 1225                                 (void *)pgrp, (long)pgrp->pg_id,
 1226                                 (void *)pgrp->pg_session,
 1227                                 pgrp->pg_session->s_count,
 1228                                 (void *)LIST_FIRST(&pgrp->pg_members));
 1229                         LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
 1230                                 kprintf("\t\tpid %ld addr %p pgrp %p\n",
 1231                                         (long)p->p_pid, (void *)p,
 1232                                         (void *)p->p_pgrp);
 1233                         }
 1234                 }
 1235         }
 1236 }
 1237 #endif /* DDB */
 1238 
 1239 /*
 1240  * The caller must hold proc_token.
 1241  */
 1242 static int
 1243 sysctl_out_proc(struct proc *p, struct sysctl_req *req, int flags)
 1244 {
 1245         struct kinfo_proc ki;
 1246         struct lwp *lp;
 1247         int skp = 0, had_output = 0;
 1248         int error;
 1249 
 1250         bzero(&ki, sizeof(ki));
 1251         lwkt_gettoken_shared(&p->p_token);
 1252         fill_kinfo_proc(p, &ki);
 1253         if ((flags & KERN_PROC_FLAG_LWP) == 0)
 1254                 skp = 1;
 1255         error = 0;
 1256         FOREACH_LWP_IN_PROC(lp, p) {
 1257                 LWPHOLD(lp);
 1258                 fill_kinfo_lwp(lp, &ki.kp_lwp);
 1259                 had_output = 1;
 1260                 error = SYSCTL_OUT(req, &ki, sizeof(ki));
 1261                 LWPRELE(lp);
 1262                 if (error)
 1263                         break;
 1264                 if (skp)
 1265                         break;
 1266         }
 1267         lwkt_reltoken(&p->p_token);
 1268         /* We need to output at least the proc, even if there is no lwp. */
 1269         if (had_output == 0) {
 1270                 error = SYSCTL_OUT(req, &ki, sizeof(ki));
 1271         }
 1272         return (error);
 1273 }
 1274 
 1275 /*
 1276  * The caller must hold proc_token.
 1277  */
 1278 static int
 1279 sysctl_out_proc_kthread(struct thread *td, struct sysctl_req *req)
 1280 {
 1281         struct kinfo_proc ki;
 1282         int error;
 1283 
 1284         fill_kinfo_proc_kthread(td, &ki);
 1285         error = SYSCTL_OUT(req, &ki, sizeof(ki));
 1286         if (error)
 1287                 return error;
 1288         return(0);
 1289 }
 1290 
 1291 /*
 1292  * No requirements.
 1293  */
 1294 static int
 1295 sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
 1296 {
 1297         int *name = (int *)arg1;
 1298         int oid = oidp->oid_number;
 1299         u_int namelen = arg2;
 1300         struct proc *p;
 1301         struct thread *td;
 1302         struct thread *marker;
 1303         int flags = 0;
 1304         int error = 0;
 1305         int n;
 1306         int origcpu;
 1307         struct ucred *cr1 = curproc->p_ucred;
 1308 
 1309         flags = oid & KERN_PROC_FLAGMASK;
 1310         oid &= ~KERN_PROC_FLAGMASK;
 1311 
 1312         if ((oid == KERN_PROC_ALL && namelen != 0) ||
 1313             (oid != KERN_PROC_ALL && namelen != 1)) {
 1314                 return (EINVAL);
 1315         }
 1316 
 1317         /*
 1318          * proc_token protects the allproc list and PHOLD() prevents the
 1319          * process from being removed from the allproc list or the zombproc
 1320          * list.
 1321          */
 1322         if (oid == KERN_PROC_PID) {
 1323                 p = pfind((pid_t)name[0]);
 1324                 if (p) {
 1325                         if (PRISON_CHECK(cr1, p->p_ucred))
 1326                                 error = sysctl_out_proc(p, req, flags);
 1327                         PRELE(p);
 1328                 }
 1329                 goto post_threads;
 1330         }
 1331         p = NULL;
 1332 
 1333         if (!req->oldptr) {
 1334                 /* overestimate by 5 procs */
 1335                 error = SYSCTL_OUT(req, 0, sizeof (struct kinfo_proc) * 5);
 1336                 if (error)
 1337                         goto post_threads;
 1338         }
 1339 
 1340         for (n = 0; n < ALLPROC_HSIZE; ++n) {
 1341                 if (LIST_EMPTY(&allprocs[n]))
 1342                         continue;
 1343                 lwkt_gettoken_shared(&proc_tokens[n]);
 1344                 LIST_FOREACH(p, &allprocs[n], p_list) {
 1345                         /*
 1346                          * Show a user only their processes.
 1347                          */
 1348                         if ((!ps_showallprocs) && p_trespass(cr1, p->p_ucred))
 1349                                 continue;
 1350                         /*
 1351                          * Skip embryonic processes.
 1352                          */
 1353                         if (p->p_stat == SIDL)
 1354                                 continue;
 1355                         /*
 1356                          * TODO - make more efficient (see notes below).
 1357                          * do by session.
 1358                          */
 1359                         switch (oid) {
 1360                         case KERN_PROC_PGRP:
 1361                                 /* could do this by traversing pgrp */
 1362                                 if (p->p_pgrp == NULL || 
 1363                                     p->p_pgrp->pg_id != (pid_t)name[0])
 1364                                         continue;
 1365                                 break;
 1366 
 1367                         case KERN_PROC_TTY:
 1368                                 if ((p->p_flags & P_CONTROLT) == 0 ||
 1369                                     p->p_session == NULL ||
 1370                                     p->p_session->s_ttyp == NULL ||
 1371                                     dev2udev(p->p_session->s_ttyp->t_dev) != 
 1372                                         (udev_t)name[0])
 1373                                         continue;
 1374                                 break;
 1375 
 1376                         case KERN_PROC_UID:
 1377                                 if (p->p_ucred == NULL || 
 1378                                     p->p_ucred->cr_uid != (uid_t)name[0])
 1379                                         continue;
 1380                                 break;
 1381 
 1382                         case KERN_PROC_RUID:
 1383                                 if (p->p_ucred == NULL || 
 1384                                     p->p_ucred->cr_ruid != (uid_t)name[0])
 1385                                         continue;
 1386                                 break;
 1387                         }
 1388 
 1389                         if (!PRISON_CHECK(cr1, p->p_ucred))
 1390                                 continue;
 1391                         PHOLD(p);
 1392                         error = sysctl_out_proc(p, req, flags);
 1393                         PRELE(p);
 1394                         if (error) {
 1395                                 lwkt_reltoken(&proc_tokens[n]);
 1396                                 goto post_threads;
 1397                         }
 1398                 }
 1399                 lwkt_reltoken(&proc_tokens[n]);
 1400         }
 1401 
 1402         /*
 1403          * Iterate over all active cpus and scan their thread list.  Start
 1404          * with the next logical cpu and end with our original cpu.  We
 1405          * migrate our own thread to each target cpu in order to safely scan
 1406          * its thread list.  In the last loop we migrate back to our original
 1407          * cpu.
 1408          */
 1409         origcpu = mycpu->gd_cpuid;
 1410         if (!ps_showallthreads || jailed(cr1))
 1411                 goto post_threads;
 1412 
 1413         marker = kmalloc(sizeof(struct thread), M_TEMP, M_WAITOK|M_ZERO);
 1414         marker->td_flags = TDF_MARKER;
 1415         error = 0;
 1416 
 1417         for (n = 1; n <= ncpus; ++n) {
 1418                 globaldata_t rgd;
 1419                 int nid;
 1420 
 1421                 nid = (origcpu + n) % ncpus;
 1422                 if ((smp_active_mask & CPUMASK(nid)) == 0)
 1423                         continue;
 1424                 rgd = globaldata_find(nid);
 1425                 lwkt_setcpu_self(rgd);
 1426 
 1427                 crit_enter();
 1428                 TAILQ_INSERT_TAIL(&rgd->gd_tdallq, marker, td_allq);
 1429 
 1430                 while ((td = TAILQ_PREV(marker, lwkt_queue, td_allq)) != NULL) {
 1431                         TAILQ_REMOVE(&rgd->gd_tdallq, marker, td_allq);
 1432                         TAILQ_INSERT_BEFORE(td, marker, td_allq);
 1433                         if (td->td_flags & TDF_MARKER)
 1434                                 continue;
 1435                         if (td->td_proc)
 1436                                 continue;
 1437 
 1438                         lwkt_hold(td);
 1439                         crit_exit();
 1440 
 1441                         switch (oid) {
 1442                         case KERN_PROC_PGRP:
 1443                         case KERN_PROC_TTY:
 1444                         case KERN_PROC_UID:
 1445                         case KERN_PROC_RUID:
 1446                                 break;
 1447                         default:
 1448                                 error = sysctl_out_proc_kthread(td, req);
 1449                                 break;
 1450                         }
 1451                         lwkt_rele(td);
 1452                         crit_enter();
 1453                         if (error)
 1454                                 break;
 1455                 }
 1456                 TAILQ_REMOVE(&rgd->gd_tdallq, marker, td_allq);
 1457                 crit_exit();
 1458 
 1459                 if (error)
 1460                         break;
 1461         }
 1462 
 1463         /*
 1464          * Userland scheduler expects us to return on the same cpu we
 1465          * started on.
 1466          */
 1467         if (mycpu->gd_cpuid != origcpu)
 1468                 lwkt_setcpu_self(globaldata_find(origcpu));
 1469 
 1470         kfree(marker, M_TEMP);
 1471 
 1472 post_threads:
 1473         return (error);
 1474 }
 1475 
 1476 /*
 1477  * This sysctl allows a process to retrieve the argument list or process
 1478  * title for another process without groping around in the address space
 1479  * of the other process.  It also allow a process to set its own "process 
 1480  * title to a string of its own choice.
 1481  *
 1482  * No requirements.
 1483  */
 1484 static int
 1485 sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
 1486 {
 1487         int *name = (int*) arg1;
 1488         u_int namelen = arg2;
 1489         struct proc *p;
 1490         struct pargs *opa;
 1491         struct pargs *pa;
 1492         int error = 0;
 1493         struct ucred *cr1 = curproc->p_ucred;
 1494 
 1495         if (namelen != 1) 
 1496                 return (EINVAL);
 1497 
 1498         p = pfind((pid_t)name[0]);
 1499         if (p == NULL)
 1500                 goto done;
 1501         lwkt_gettoken(&p->p_token);
 1502 
 1503         if ((!ps_argsopen) && p_trespass(cr1, p->p_ucred))
 1504                 goto done;
 1505 
 1506         if (req->newptr && curproc != p) {
 1507                 error = EPERM;
 1508                 goto done;
 1509         }
 1510         if (req->oldptr && (pa = p->p_args) != NULL) {
 1511                 refcount_acquire(&pa->ar_ref);
 1512                 error = SYSCTL_OUT(req, pa->ar_args, pa->ar_length);
 1513                 if (refcount_release(&pa->ar_ref))
 1514                         kfree(pa, M_PARGS);
 1515         }
 1516         if (req->newptr == NULL)
 1517                 goto done;
 1518 
 1519         if (req->newlen + sizeof(struct pargs) > ps_arg_cache_limit) {
 1520                 goto done;
 1521         }
 1522 
 1523         pa = kmalloc(sizeof(struct pargs) + req->newlen, M_PARGS, M_WAITOK);
 1524         refcount_init(&pa->ar_ref, 1);
 1525         pa->ar_length = req->newlen;
 1526         error = SYSCTL_IN(req, pa->ar_args, req->newlen);
 1527         if (error) {
 1528                 kfree(pa, M_PARGS);
 1529                 goto done;
 1530         }
 1531 
 1532 
 1533         /*
 1534          * Replace p_args with the new pa.  p_args may have previously
 1535          * been NULL.
 1536          */
 1537         opa = p->p_args;
 1538         p->p_args = pa;
 1539 
 1540         if (opa) {
 1541                 KKASSERT(opa->ar_ref > 0);
 1542                 if (refcount_release(&opa->ar_ref)) {
 1543                         kfree(opa, M_PARGS);
 1544                         /* opa = NULL; */
 1545                 }
 1546         }
 1547 done:
 1548         if (p) {
 1549                 lwkt_reltoken(&p->p_token);
 1550                 PRELE(p);
 1551         }
 1552         return (error);
 1553 }
 1554 
 1555 static int
 1556 sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS)
 1557 {
 1558         int *name = (int*) arg1;
 1559         u_int namelen = arg2;
 1560         struct proc *p;
 1561         int error = 0;
 1562         char *fullpath, *freepath;
 1563         struct ucred *cr1 = curproc->p_ucred;
 1564 
 1565         if (namelen != 1) 
 1566                 return (EINVAL);
 1567 
 1568         p = pfind((pid_t)name[0]);
 1569         if (p == NULL)
 1570                 goto done;
 1571         lwkt_gettoken_shared(&p->p_token);
 1572 
 1573         /*
 1574          * If we are not allowed to see other args, we certainly shouldn't
 1575          * get the cwd either. Also check the usual trespassing.
 1576          */
 1577         if ((!ps_argsopen) && p_trespass(cr1, p->p_ucred))
 1578                 goto done;
 1579 
 1580         if (req->oldptr && p->p_fd != NULL && p->p_fd->fd_ncdir.ncp) {
 1581                 struct nchandle nch;
 1582 
 1583                 cache_copy(&p->p_fd->fd_ncdir, &nch);
 1584                 error = cache_fullpath(p, &nch, NULL,
 1585                                        &fullpath, &freepath, 0);
 1586                 cache_drop(&nch);
 1587                 if (error)
 1588                         goto done;
 1589                 error = SYSCTL_OUT(req, fullpath, strlen(fullpath) + 1);
 1590                 kfree(freepath, M_TEMP);
 1591         }
 1592 
 1593 done:
 1594         if (p) {
 1595                 lwkt_reltoken(&p->p_token);
 1596                 PRELE(p);
 1597         }
 1598         return (error);
 1599 }
 1600 
 1601 SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD,  0, "Process table");
 1602 
 1603 SYSCTL_PROC(_kern_proc, KERN_PROC_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT,
 1604         0, 0, sysctl_kern_proc, "S,proc", "Return entire process table");
 1605 
 1606 SYSCTL_NODE(_kern_proc, KERN_PROC_PGRP, pgrp, CTLFLAG_RD, 
 1607         sysctl_kern_proc, "Process table");
 1608 
 1609 SYSCTL_NODE(_kern_proc, KERN_PROC_TTY, tty, CTLFLAG_RD, 
 1610         sysctl_kern_proc, "Process table");
 1611 
 1612 SYSCTL_NODE(_kern_proc, KERN_PROC_UID, uid, CTLFLAG_RD, 
 1613         sysctl_kern_proc, "Process table");
 1614 
 1615 SYSCTL_NODE(_kern_proc, KERN_PROC_RUID, ruid, CTLFLAG_RD, 
 1616         sysctl_kern_proc, "Process table");
 1617 
 1618 SYSCTL_NODE(_kern_proc, KERN_PROC_PID, pid, CTLFLAG_RD, 
 1619         sysctl_kern_proc, "Process table");
 1620 
 1621 SYSCTL_NODE(_kern_proc, (KERN_PROC_ALL | KERN_PROC_FLAG_LWP), all_lwp, CTLFLAG_RD,
 1622         sysctl_kern_proc, "Process table");
 1623 
 1624 SYSCTL_NODE(_kern_proc, (KERN_PROC_PGRP | KERN_PROC_FLAG_LWP), pgrp_lwp, CTLFLAG_RD, 
 1625         sysctl_kern_proc, "Process table");
 1626 
 1627 SYSCTL_NODE(_kern_proc, (KERN_PROC_TTY | KERN_PROC_FLAG_LWP), tty_lwp, CTLFLAG_RD, 
 1628         sysctl_kern_proc, "Process table");
 1629 
 1630 SYSCTL_NODE(_kern_proc, (KERN_PROC_UID | KERN_PROC_FLAG_LWP), uid_lwp, CTLFLAG_RD, 
 1631         sysctl_kern_proc, "Process table");
 1632 
 1633 SYSCTL_NODE(_kern_proc, (KERN_PROC_RUID | KERN_PROC_FLAG_LWP), ruid_lwp, CTLFLAG_RD, 
 1634         sysctl_kern_proc, "Process table");
 1635 
 1636 SYSCTL_NODE(_kern_proc, (KERN_PROC_PID | KERN_PROC_FLAG_LWP), pid_lwp, CTLFLAG_RD, 
 1637         sysctl_kern_proc, "Process table");
 1638 
 1639 SYSCTL_NODE(_kern_proc, KERN_PROC_ARGS, args, CTLFLAG_RW | CTLFLAG_ANYBODY,
 1640         sysctl_kern_proc_args, "Process argument list");
 1641 
 1642 SYSCTL_NODE(_kern_proc, KERN_PROC_CWD, cwd, CTLFLAG_RD | CTLFLAG_ANYBODY,
 1643         sysctl_kern_proc_cwd, "Process argument list");
Cache object: 61e9692aa999f0180eff4e007f77a721
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_proc.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_proc.c
