kern_thr.c

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    1 /*-
    2  * Copyright (c) 2003, Jeffrey Roberson <jeff@freebsd.org>
    3  * 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 unmodified, this list of conditions, and the following
   10  *    disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/11.0/sys/kern/kern_thr.c 302195 2016-06-25 11:31:25Z kib $");
   29 
   30 #include "opt_compat.h"
   31 #include "opt_posix.h"
   32 #include <sys/param.h>
   33 #include <sys/kernel.h>
   34 #include <sys/lock.h>
   35 #include <sys/mutex.h>
   36 #include <sys/priv.h>
   37 #include <sys/proc.h>
   38 #include <sys/posix4.h>
   39 #include <sys/racct.h>
   40 #include <sys/resourcevar.h>
   41 #include <sys/rwlock.h>
   42 #include <sys/sched.h>
   43 #include <sys/sysctl.h>
   44 #include <sys/smp.h>
   45 #include <sys/syscallsubr.h>
   46 #include <sys/sysent.h>
   47 #include <sys/systm.h>
   48 #include <sys/sysproto.h>
   49 #include <sys/signalvar.h>
   50 #include <sys/sysctl.h>
   51 #include <sys/ucontext.h>
   52 #include <sys/thr.h>
   53 #include <sys/rtprio.h>
   54 #include <sys/umtx.h>
   55 #include <sys/limits.h>
   56 
   57 #include <vm/vm_domain.h>
   58 
   59 #include <machine/frame.h>
   60 
   61 #include <security/audit/audit.h>
   62 
   63 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
   64     "thread allocation");
   65 
   66 static int max_threads_per_proc = 1500;
   67 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
   68     &max_threads_per_proc, 0, "Limit on threads per proc");
   69 
   70 static int max_threads_hits;
   71 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
   72     &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
   73 
   74 #ifdef COMPAT_FREEBSD32
   75 
   76 static inline int
   77 suword_lwpid(void *addr, lwpid_t lwpid)
   78 {
   79         int error;
   80 
   81         if (SV_CURPROC_FLAG(SV_LP64))
   82                 error = suword(addr, lwpid);
   83         else
   84                 error = suword32(addr, lwpid);
   85         return (error);
   86 }
   87 
   88 #else
   89 #define suword_lwpid    suword
   90 #endif
   91 
   92 /*
   93  * System call interface.
   94  */
   95 
   96 struct thr_create_initthr_args {
   97         ucontext_t ctx;
   98         long *tid;
   99 };
  100 
  101 static int
  102 thr_create_initthr(struct thread *td, void *thunk)
  103 {
  104         struct thr_create_initthr_args *args;
  105 
  106         /* Copy out the child tid. */
  107         args = thunk;
  108         if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
  109                 return (EFAULT);
  110 
  111         return (set_mcontext(td, &args->ctx.uc_mcontext));
  112 }
  113 
  114 int
  115 sys_thr_create(struct thread *td, struct thr_create_args *uap)
  116     /* ucontext_t *ctx, long *id, int flags */
  117 {
  118         struct thr_create_initthr_args args;
  119         int error;
  120 
  121         if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
  122                 return (error);
  123         args.tid = uap->id;
  124         return (thread_create(td, NULL, thr_create_initthr, &args));
  125 }
  126 
  127 int
  128 sys_thr_new(struct thread *td, struct thr_new_args *uap)
  129     /* struct thr_param * */
  130 {
  131         struct thr_param param;
  132         int error;
  133 
  134         if (uap->param_size < 0 || uap->param_size > sizeof(param))
  135                 return (EINVAL);
  136         bzero(&param, sizeof(param));
  137         if ((error = copyin(uap->param, &param, uap->param_size)))
  138                 return (error);
  139         return (kern_thr_new(td, &param));
  140 }
  141 
  142 static int
  143 thr_new_initthr(struct thread *td, void *thunk)
  144 {
  145         stack_t stack;
  146         struct thr_param *param;
  147 
  148         /*
  149          * Here we copy out tid to two places, one for child and one
  150          * for parent, because pthread can create a detached thread,
  151          * if parent wants to safely access child tid, it has to provide
  152          * its storage, because child thread may exit quickly and
  153          * memory is freed before parent thread can access it.
  154          */
  155         param = thunk;
  156         if ((param->child_tid != NULL &&
  157             suword_lwpid(param->child_tid, td->td_tid)) ||
  158             (param->parent_tid != NULL &&
  159             suword_lwpid(param->parent_tid, td->td_tid)))
  160                 return (EFAULT);
  161 
  162         /* Set up our machine context. */
  163         stack.ss_sp = param->stack_base;
  164         stack.ss_size = param->stack_size;
  165         /* Set upcall address to user thread entry function. */
  166         cpu_set_upcall(td, param->start_func, param->arg, &stack);
  167         /* Setup user TLS address and TLS pointer register. */
  168         return (cpu_set_user_tls(td, param->tls_base));
  169 }
  170 
  171 int
  172 kern_thr_new(struct thread *td, struct thr_param *param)
  173 {
  174         struct rtprio rtp, *rtpp;
  175         int error;
  176 
  177         rtpp = NULL;
  178         if (param->rtp != 0) {
  179                 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
  180                 if (error)
  181                         return (error);
  182                 rtpp = &rtp;
  183         }
  184         return (thread_create(td, rtpp, thr_new_initthr, param));
  185 }
  186 
  187 int
  188 thread_create(struct thread *td, struct rtprio *rtp,
  189     int (*initialize_thread)(struct thread *, void *), void *thunk)
  190 {
  191         struct thread *newtd;
  192         struct proc *p;
  193         int error;
  194 
  195         p = td->td_proc;
  196 
  197         if (rtp != NULL) {
  198                 switch(rtp->type) {
  199                 case RTP_PRIO_REALTIME:
  200                 case RTP_PRIO_FIFO:
  201                         /* Only root can set scheduler policy */
  202                         if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
  203                                 return (EPERM);
  204                         if (rtp->prio > RTP_PRIO_MAX)
  205                                 return (EINVAL);
  206                         break;
  207                 case RTP_PRIO_NORMAL:
  208                         rtp->prio = 0;
  209                         break;
  210                 default:
  211                         return (EINVAL);
  212                 }
  213         }
  214 
  215 #ifdef RACCT
  216         if (racct_enable) {
  217                 PROC_LOCK(p);
  218                 error = racct_add(p, RACCT_NTHR, 1);
  219                 PROC_UNLOCK(p);
  220                 if (error != 0)
  221                         return (EPROCLIM);
  222         }
  223 #endif
  224 
  225         /* Initialize our td */
  226         error = kern_thr_alloc(p, 0, &newtd);
  227         if (error)
  228                 goto fail;
  229 
  230         cpu_copy_thread(newtd, td);
  231 
  232         bzero(&newtd->td_startzero,
  233             __rangeof(struct thread, td_startzero, td_endzero));
  234         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  235             __rangeof(struct thread, td_startcopy, td_endcopy));
  236         newtd->td_proc = td->td_proc;
  237         newtd->td_rb_list = newtd->td_rbp_list = newtd->td_rb_inact = 0;
  238         thread_cow_get(newtd, td);
  239 
  240         error = initialize_thread(newtd, thunk);
  241         if (error != 0) {
  242                 thread_cow_free(newtd);
  243                 thread_free(newtd);
  244                 goto fail;
  245         }
  246 
  247         PROC_LOCK(p);
  248         p->p_flag |= P_HADTHREADS;
  249         thread_link(newtd, p);
  250         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  251         thread_lock(td);
  252         /* let the scheduler know about these things. */
  253         sched_fork_thread(td, newtd);
  254         thread_unlock(td);
  255         if (P_SHOULDSTOP(p))
  256                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  257         if (p->p_flag2 & P2_LWP_EVENTS)
  258                 newtd->td_dbgflags |= TDB_BORN;
  259 
  260         /*
  261          * Copy the existing thread VM policy into the new thread.
  262          */
  263         vm_domain_policy_localcopy(&newtd->td_vm_dom_policy,
  264             &td->td_vm_dom_policy);
  265 
  266         PROC_UNLOCK(p);
  267 
  268         tidhash_add(newtd);
  269 
  270         thread_lock(newtd);
  271         if (rtp != NULL) {
  272                 if (!(td->td_pri_class == PRI_TIMESHARE &&
  273                       rtp->type == RTP_PRIO_NORMAL)) {
  274                         rtp_to_pri(rtp, newtd);
  275                         sched_prio(newtd, newtd->td_user_pri);
  276                 } /* ignore timesharing class */
  277         }
  278         TD_SET_CAN_RUN(newtd);
  279         sched_add(newtd, SRQ_BORING);
  280         thread_unlock(newtd);
  281 
  282         return (0);
  283 
  284 fail:
  285 #ifdef RACCT
  286         if (racct_enable) {
  287                 PROC_LOCK(p);
  288                 racct_sub(p, RACCT_NTHR, 1);
  289                 PROC_UNLOCK(p);
  290         }
  291 #endif
  292         return (error);
  293 }
  294 
  295 int
  296 sys_thr_self(struct thread *td, struct thr_self_args *uap)
  297     /* long *id */
  298 {
  299         int error;
  300 
  301         error = suword_lwpid(uap->id, (unsigned)td->td_tid);
  302         if (error == -1)
  303                 return (EFAULT);
  304         return (0);
  305 }
  306 
  307 int
  308 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
  309     /* long *state */
  310 {
  311 
  312         umtx_thread_exit(td);
  313 
  314         /* Signal userland that it can free the stack. */
  315         if ((void *)uap->state != NULL) {
  316                 suword_lwpid(uap->state, 1);
  317                 kern_umtx_wake(td, uap->state, INT_MAX, 0);
  318         }
  319 
  320         return (kern_thr_exit(td));
  321 }
  322 
  323 int
  324 kern_thr_exit(struct thread *td)
  325 {
  326         struct proc *p;
  327 
  328         p = td->td_proc;
  329 
  330         /*
  331          * If all of the threads in a process call this routine to
  332          * exit (e.g. all threads call pthread_exit()), exactly one
  333          * thread should return to the caller to terminate the process
  334          * instead of the thread.
  335          *
  336          * Checking p_numthreads alone is not sufficient since threads
  337          * might be committed to terminating while the PROC_LOCK is
  338          * dropped in either ptracestop() or while removing this thread
  339          * from the tidhash.  Instead, the p_pendingexits field holds
  340          * the count of threads in either of those states and a thread
  341          * is considered the "last" thread if all of the other threads
  342          * in a process are already terminating.
  343          */
  344         PROC_LOCK(p);
  345         if (p->p_numthreads == p->p_pendingexits + 1) {
  346                 /*
  347                  * Ignore attempts to shut down last thread in the
  348                  * proc.  This will actually call _exit(2) in the
  349                  * usermode trampoline when it returns.
  350                  */
  351                 PROC_UNLOCK(p);
  352                 return (0);
  353         }
  354 
  355         p->p_pendingexits++;
  356         td->td_dbgflags |= TDB_EXIT;
  357         if (p->p_flag & P_TRACED && p->p_flag2 & P2_LWP_EVENTS)
  358                 ptracestop(td, SIGTRAP);
  359         PROC_UNLOCK(p);
  360         tidhash_remove(td);
  361         PROC_LOCK(p);
  362         p->p_pendingexits--;
  363 
  364         /*
  365          * The check above should prevent all other threads from this
  366          * process from exiting while the PROC_LOCK is dropped, so
  367          * there must be at least one other thread other than the
  368          * current thread.
  369          */
  370         KASSERT(p->p_numthreads > 1, ("too few threads"));
  371         racct_sub(p, RACCT_NTHR, 1);
  372         tdsigcleanup(td);
  373         PROC_SLOCK(p);
  374         thread_stopped(p);
  375         thread_exit();
  376         /* NOTREACHED */
  377 }
  378 
  379 int
  380 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  381     /* long id, int sig */
  382 {
  383         ksiginfo_t ksi;
  384         struct thread *ttd;
  385         struct proc *p;
  386         int error;
  387 
  388         p = td->td_proc;
  389         ksiginfo_init(&ksi);
  390         ksi.ksi_signo = uap->sig;
  391         ksi.ksi_code = SI_LWP;
  392         ksi.ksi_pid = p->p_pid;
  393         ksi.ksi_uid = td->td_ucred->cr_ruid;
  394         if (uap->id == -1) {
  395                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  396                         error = EINVAL;
  397                 } else {
  398                         error = ESRCH;
  399                         PROC_LOCK(p);
  400                         FOREACH_THREAD_IN_PROC(p, ttd) {
  401                                 if (ttd != td) {
  402                                         error = 0;
  403                                         if (uap->sig == 0)
  404                                                 break;
  405                                         tdksignal(ttd, uap->sig, &ksi);
  406                                 }
  407                         }
  408                         PROC_UNLOCK(p);
  409                 }
  410         } else {
  411                 error = 0;
  412                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  413                 if (ttd == NULL)
  414                         return (ESRCH);
  415                 if (uap->sig == 0)
  416                         ;
  417                 else if (!_SIG_VALID(uap->sig))
  418                         error = EINVAL;
  419                 else 
  420                         tdksignal(ttd, uap->sig, &ksi);
  421                 PROC_UNLOCK(ttd->td_proc);
  422         }
  423         return (error);
  424 }
  425 
  426 int
  427 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  428     /* pid_t pid, long id, int sig */
  429 {
  430         ksiginfo_t ksi;
  431         struct thread *ttd;
  432         struct proc *p;
  433         int error;
  434 
  435         AUDIT_ARG_SIGNUM(uap->sig);
  436 
  437         ksiginfo_init(&ksi);
  438         ksi.ksi_signo = uap->sig;
  439         ksi.ksi_code = SI_LWP;
  440         ksi.ksi_pid = td->td_proc->p_pid;
  441         ksi.ksi_uid = td->td_ucred->cr_ruid;
  442         if (uap->id == -1) {
  443                 if ((p = pfind(uap->pid)) == NULL)
  444                         return (ESRCH);
  445                 AUDIT_ARG_PROCESS(p);
  446                 error = p_cansignal(td, p, uap->sig);
  447                 if (error) {
  448                         PROC_UNLOCK(p);
  449                         return (error);
  450                 }
  451                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  452                         error = EINVAL;
  453                 } else {
  454                         error = ESRCH;
  455                         FOREACH_THREAD_IN_PROC(p, ttd) {
  456                                 if (ttd != td) {
  457                                         error = 0;
  458                                         if (uap->sig == 0)
  459                                                 break;
  460                                         tdksignal(ttd, uap->sig, &ksi);
  461                                 }
  462                         }
  463                 }
  464                 PROC_UNLOCK(p);
  465         } else {
  466                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  467                 if (ttd == NULL)
  468                         return (ESRCH);
  469                 p = ttd->td_proc;
  470                 AUDIT_ARG_PROCESS(p);
  471                 error = p_cansignal(td, p, uap->sig);
  472                 if (uap->sig == 0)
  473                         ;
  474                 else if (!_SIG_VALID(uap->sig))
  475                         error = EINVAL;
  476                 else
  477                         tdksignal(ttd, uap->sig, &ksi);
  478                 PROC_UNLOCK(p);
  479         }
  480         return (error);
  481 }
  482 
  483 int
  484 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  485         /* const struct timespec *timeout */
  486 {
  487         struct timespec ts, *tsp;
  488         int error;
  489 
  490         tsp = NULL;
  491         if (uap->timeout != NULL) {
  492                 error = umtx_copyin_timeout(uap->timeout, &ts);
  493                 if (error != 0)
  494                         return (error);
  495                 tsp = &ts;
  496         }
  497 
  498         return (kern_thr_suspend(td, tsp));
  499 }
  500 
  501 int
  502 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  503 {
  504         struct proc *p = td->td_proc;
  505         struct timeval tv;
  506         int error = 0;
  507         int timo = 0;
  508 
  509         if (td->td_pflags & TDP_WAKEUP) {
  510                 td->td_pflags &= ~TDP_WAKEUP;
  511                 return (0);
  512         }
  513 
  514         if (tsp != NULL) {
  515                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  516                         error = EWOULDBLOCK;
  517                 else {
  518                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  519                         timo = tvtohz(&tv);
  520                 }
  521         }
  522 
  523         PROC_LOCK(p);
  524         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  525                 error = msleep((void *)td, &p->p_mtx,
  526                          PCATCH, "lthr", timo);
  527 
  528         if (td->td_flags & TDF_THRWAKEUP) {
  529                 thread_lock(td);
  530                 td->td_flags &= ~TDF_THRWAKEUP;
  531                 thread_unlock(td);
  532                 PROC_UNLOCK(p);
  533                 return (0);
  534         }
  535         PROC_UNLOCK(p);
  536         if (error == EWOULDBLOCK)
  537                 error = ETIMEDOUT;
  538         else if (error == ERESTART) {
  539                 if (timo != 0)
  540                         error = EINTR;
  541         }
  542         return (error);
  543 }
  544 
  545 int
  546 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  547         /* long id */
  548 {
  549         struct proc *p;
  550         struct thread *ttd;
  551 
  552         if (uap->id == td->td_tid) {
  553                 td->td_pflags |= TDP_WAKEUP;
  554                 return (0);
  555         } 
  556 
  557         p = td->td_proc;
  558         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  559         if (ttd == NULL)
  560                 return (ESRCH);
  561         thread_lock(ttd);
  562         ttd->td_flags |= TDF_THRWAKEUP;
  563         thread_unlock(ttd);
  564         wakeup((void *)ttd);
  565         PROC_UNLOCK(p);
  566         return (0);
  567 }
  568 
  569 int
  570 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  571 {
  572         struct proc *p;
  573         char name[MAXCOMLEN + 1];
  574         struct thread *ttd;
  575         int error;
  576 
  577         error = 0;
  578         name[0] = '\0';
  579         if (uap->name != NULL) {
  580                 error = copyinstr(uap->name, name, sizeof(name),
  581                         NULL);
  582                 if (error)
  583                         return (error);
  584         }
  585         p = td->td_proc;
  586         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  587         if (ttd == NULL)
  588                 return (ESRCH);
  589         strcpy(ttd->td_name, name);
  590 #ifdef KTR
  591         sched_clear_tdname(ttd);
  592 #endif
  593         PROC_UNLOCK(p);
  594         return (error);
  595 }
  596 
  597 int
  598 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
  599 {
  600 
  601         /* Have race condition but it is cheap. */
  602         if (p->p_numthreads >= max_threads_per_proc) {
  603                 ++max_threads_hits;
  604                 return (EPROCLIM);
  605         }
  606 
  607         *ntd = thread_alloc(pages);
  608         if (*ntd == NULL)
  609                 return (ENOMEM);
  610 
  611         return (0);
  612 }
Cache object: 0851026045cccdd9df191f6c238a4a4e
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_thr.c

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