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/11.2/sys/kern/kern_thr.c 331842 2018-03-31 13:19:27Z 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/ptrace.h>
   40 #include <sys/racct.h>
   41 #include <sys/resourcevar.h>
   42 #include <sys/rwlock.h>
   43 #include <sys/sched.h>
   44 #include <sys/sysctl.h>
   45 #include <sys/smp.h>
   46 #include <sys/syscallsubr.h>
   47 #include <sys/sysent.h>
   48 #include <sys/systm.h>
   49 #include <sys/sysproto.h>
   50 #include <sys/signalvar.h>
   51 #include <sys/sysctl.h>
   52 #include <sys/ucontext.h>
   53 #include <sys/thr.h>
   54 #include <sys/rtprio.h>
   55 #include <sys/umtx.h>
   56 #include <sys/limits.h>
   57 
   58 #include <vm/vm_domain.h>
   59 
   60 #include <machine/frame.h>
   61 
   62 #include <security/audit/audit.h>
   63 
   64 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
   65     "thread allocation");
   66 
   67 static int max_threads_per_proc = 1500;
   68 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
   69     &max_threads_per_proc, 0, "Limit on threads per proc");
   70 
   71 static int max_threads_hits;
   72 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
   73     &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
   74 
   75 #ifdef COMPAT_FREEBSD32
   76 
   77 static inline int
   78 suword_lwpid(void *addr, lwpid_t lwpid)
   79 {
   80         int error;
   81 
   82         if (SV_CURPROC_FLAG(SV_LP64))
   83                 error = suword(addr, lwpid);
   84         else
   85                 error = suword32(addr, lwpid);
   86         return (error);
   87 }
   88 
   89 #else
   90 #define suword_lwpid    suword
   91 #endif
   92 
   93 /*
   94  * System call interface.
   95  */
   96 
   97 struct thr_create_initthr_args {
   98         ucontext_t ctx;
   99         long *tid;
  100 };
  101 
  102 static int
  103 thr_create_initthr(struct thread *td, void *thunk)
  104 {
  105         struct thr_create_initthr_args *args;
  106 
  107         /* Copy out the child tid. */
  108         args = thunk;
  109         if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
  110                 return (EFAULT);
  111 
  112         return (set_mcontext(td, &args->ctx.uc_mcontext));
  113 }
  114 
  115 int
  116 sys_thr_create(struct thread *td, struct thr_create_args *uap)
  117     /* ucontext_t *ctx, long *id, int flags */
  118 {
  119         struct thr_create_initthr_args args;
  120         int error;
  121 
  122         if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
  123                 return (error);
  124         args.tid = uap->id;
  125         return (thread_create(td, NULL, thr_create_initthr, &args));
  126 }
  127 
  128 int
  129 sys_thr_new(struct thread *td, struct thr_new_args *uap)
  130     /* struct thr_param * */
  131 {
  132         struct thr_param param;
  133         int error;
  134 
  135         if (uap->param_size < 0 || uap->param_size > sizeof(param))
  136                 return (EINVAL);
  137         bzero(&param, sizeof(param));
  138         if ((error = copyin(uap->param, &param, uap->param_size)))
  139                 return (error);
  140         return (kern_thr_new(td, &param));
  141 }
  142 
  143 static int
  144 thr_new_initthr(struct thread *td, void *thunk)
  145 {
  146         stack_t stack;
  147         struct thr_param *param;
  148 
  149         /*
  150          * Here we copy out tid to two places, one for child and one
  151          * for parent, because pthread can create a detached thread,
  152          * if parent wants to safely access child tid, it has to provide
  153          * its storage, because child thread may exit quickly and
  154          * memory is freed before parent thread can access it.
  155          */
  156         param = thunk;
  157         if ((param->child_tid != NULL &&
  158             suword_lwpid(param->child_tid, td->td_tid)) ||
  159             (param->parent_tid != NULL &&
  160             suword_lwpid(param->parent_tid, td->td_tid)))
  161                 return (EFAULT);
  162 
  163         /* Set up our machine context. */
  164         stack.ss_sp = param->stack_base;
  165         stack.ss_size = param->stack_size;
  166         /* Set upcall address to user thread entry function. */
  167         cpu_set_upcall(td, param->start_func, param->arg, &stack);
  168         /* Setup user TLS address and TLS pointer register. */
  169         return (cpu_set_user_tls(td, param->tls_base));
  170 }
  171 
  172 int
  173 kern_thr_new(struct thread *td, struct thr_param *param)
  174 {
  175         struct rtprio rtp, *rtpp;
  176         int error;
  177 
  178         rtpp = NULL;
  179         if (param->rtp != 0) {
  180                 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
  181                 if (error)
  182                         return (error);
  183                 rtpp = &rtp;
  184         }
  185         return (thread_create(td, rtpp, thr_new_initthr, param));
  186 }
  187 
  188 int
  189 thread_create(struct thread *td, struct rtprio *rtp,
  190     int (*initialize_thread)(struct thread *, void *), void *thunk)
  191 {
  192         struct thread *newtd;
  193         struct proc *p;
  194         int error;
  195 
  196         p = td->td_proc;
  197 
  198         if (rtp != NULL) {
  199                 switch(rtp->type) {
  200                 case RTP_PRIO_REALTIME:
  201                 case RTP_PRIO_FIFO:
  202                         /* Only root can set scheduler policy */
  203                         if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
  204                                 return (EPERM);
  205                         if (rtp->prio > RTP_PRIO_MAX)
  206                                 return (EINVAL);
  207                         break;
  208                 case RTP_PRIO_NORMAL:
  209                         rtp->prio = 0;
  210                         break;
  211                 default:
  212                         return (EINVAL);
  213                 }
  214         }
  215 
  216 #ifdef RACCT
  217         if (racct_enable) {
  218                 PROC_LOCK(p);
  219                 error = racct_add(p, RACCT_NTHR, 1);
  220                 PROC_UNLOCK(p);
  221                 if (error != 0)
  222                         return (EPROCLIM);
  223         }
  224 #endif
  225 
  226         /* Initialize our td */
  227         error = kern_thr_alloc(p, 0, &newtd);
  228         if (error)
  229                 goto fail;
  230 
  231         cpu_copy_thread(newtd, td);
  232 
  233         bzero(&newtd->td_startzero,
  234             __rangeof(struct thread, td_startzero, td_endzero));
  235         newtd->td_sleeptimo = 0;
  236         newtd->td_vslock_sz = 0;
  237         bzero(&newtd->td_si, sizeof(newtd->td_si));
  238         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  239             __rangeof(struct thread, td_startcopy, td_endcopy));
  240         newtd->td_sa = td->td_sa;
  241         newtd->td_proc = td->td_proc;
  242         newtd->td_rb_list = newtd->td_rbp_list = newtd->td_rb_inact = 0;
  243         thread_cow_get(newtd, td);
  244 
  245         error = initialize_thread(newtd, thunk);
  246         if (error != 0) {
  247                 thread_cow_free(newtd);
  248                 thread_free(newtd);
  249                 goto fail;
  250         }
  251 
  252         PROC_LOCK(p);
  253         p->p_flag |= P_HADTHREADS;
  254         thread_link(newtd, p);
  255         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  256         thread_lock(td);
  257         /* let the scheduler know about these things. */
  258         sched_fork_thread(td, newtd);
  259         thread_unlock(td);
  260         if (P_SHOULDSTOP(p))
  261                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  262         if (p->p_ptevents & PTRACE_LWP)
  263                 newtd->td_dbgflags |= TDB_BORN;
  264 
  265         /*
  266          * Copy the existing thread VM policy into the new thread.
  267          */
  268         vm_domain_policy_localcopy(&newtd->td_vm_dom_policy,
  269             &td->td_vm_dom_policy);
  270 
  271         PROC_UNLOCK(p);
  272 
  273         tidhash_add(newtd);
  274 
  275         thread_lock(newtd);
  276         if (rtp != NULL) {
  277                 if (!(td->td_pri_class == PRI_TIMESHARE &&
  278                       rtp->type == RTP_PRIO_NORMAL)) {
  279                         rtp_to_pri(rtp, newtd);
  280                         sched_prio(newtd, newtd->td_user_pri);
  281                 } /* ignore timesharing class */
  282         }
  283         TD_SET_CAN_RUN(newtd);
  284         sched_add(newtd, SRQ_BORING);
  285         thread_unlock(newtd);
  286 
  287         return (0);
  288 
  289 fail:
  290 #ifdef RACCT
  291         if (racct_enable) {
  292                 PROC_LOCK(p);
  293                 racct_sub(p, RACCT_NTHR, 1);
  294                 PROC_UNLOCK(p);
  295         }
  296 #endif
  297         return (error);
  298 }
  299 
  300 int
  301 sys_thr_self(struct thread *td, struct thr_self_args *uap)
  302     /* long *id */
  303 {
  304         int error;
  305 
  306         error = suword_lwpid(uap->id, (unsigned)td->td_tid);
  307         if (error == -1)
  308                 return (EFAULT);
  309         return (0);
  310 }
  311 
  312 int
  313 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
  314     /* long *state */
  315 {
  316 
  317         umtx_thread_exit(td);
  318 
  319         /* Signal userland that it can free the stack. */
  320         if ((void *)uap->state != NULL) {
  321                 suword_lwpid(uap->state, 1);
  322                 kern_umtx_wake(td, uap->state, INT_MAX, 0);
  323         }
  324 
  325         return (kern_thr_exit(td));
  326 }
  327 
  328 int
  329 kern_thr_exit(struct thread *td)
  330 {
  331         struct proc *p;
  332 
  333         p = td->td_proc;
  334 
  335         /*
  336          * If all of the threads in a process call this routine to
  337          * exit (e.g. all threads call pthread_exit()), exactly one
  338          * thread should return to the caller to terminate the process
  339          * instead of the thread.
  340          *
  341          * Checking p_numthreads alone is not sufficient since threads
  342          * might be committed to terminating while the PROC_LOCK is
  343          * dropped in either ptracestop() or while removing this thread
  344          * from the tidhash.  Instead, the p_pendingexits field holds
  345          * the count of threads in either of those states and a thread
  346          * is considered the "last" thread if all of the other threads
  347          * in a process are already terminating.
  348          */
  349         PROC_LOCK(p);
  350         if (p->p_numthreads == p->p_pendingexits + 1) {
  351                 /*
  352                  * Ignore attempts to shut down last thread in the
  353                  * proc.  This will actually call _exit(2) in the
  354                  * usermode trampoline when it returns.
  355                  */
  356                 PROC_UNLOCK(p);
  357                 return (0);
  358         }
  359 
  360         p->p_pendingexits++;
  361         td->td_dbgflags |= TDB_EXIT;
  362         if (p->p_ptevents & PTRACE_LWP)
  363                 ptracestop(td, SIGTRAP, NULL);
  364         PROC_UNLOCK(p);
  365         tidhash_remove(td);
  366         PROC_LOCK(p);
  367         p->p_pendingexits--;
  368 
  369         /*
  370          * The check above should prevent all other threads from this
  371          * process from exiting while the PROC_LOCK is dropped, so
  372          * there must be at least one other thread other than the
  373          * current thread.
  374          */
  375         KASSERT(p->p_numthreads > 1, ("too few threads"));
  376         racct_sub(p, RACCT_NTHR, 1);
  377         tdsigcleanup(td);
  378         PROC_SLOCK(p);
  379         thread_stopped(p);
  380         thread_exit();
  381         /* NOTREACHED */
  382 }
  383 
  384 int
  385 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  386     /* long id, int sig */
  387 {
  388         ksiginfo_t ksi;
  389         struct thread *ttd;
  390         struct proc *p;
  391         int error;
  392 
  393         p = td->td_proc;
  394         ksiginfo_init(&ksi);
  395         ksi.ksi_signo = uap->sig;
  396         ksi.ksi_code = SI_LWP;
  397         ksi.ksi_pid = p->p_pid;
  398         ksi.ksi_uid = td->td_ucred->cr_ruid;
  399         if (uap->id == -1) {
  400                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  401                         error = EINVAL;
  402                 } else {
  403                         error = ESRCH;
  404                         PROC_LOCK(p);
  405                         FOREACH_THREAD_IN_PROC(p, ttd) {
  406                                 if (ttd != td) {
  407                                         error = 0;
  408                                         if (uap->sig == 0)
  409                                                 break;
  410                                         tdksignal(ttd, uap->sig, &ksi);
  411                                 }
  412                         }
  413                         PROC_UNLOCK(p);
  414                 }
  415         } else {
  416                 error = 0;
  417                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  418                 if (ttd == NULL)
  419                         return (ESRCH);
  420                 if (uap->sig == 0)
  421                         ;
  422                 else if (!_SIG_VALID(uap->sig))
  423                         error = EINVAL;
  424                 else 
  425                         tdksignal(ttd, uap->sig, &ksi);
  426                 PROC_UNLOCK(ttd->td_proc);
  427         }
  428         return (error);
  429 }
  430 
  431 int
  432 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  433     /* pid_t pid, long id, int sig */
  434 {
  435         ksiginfo_t ksi;
  436         struct thread *ttd;
  437         struct proc *p;
  438         int error;
  439 
  440         AUDIT_ARG_SIGNUM(uap->sig);
  441 
  442         ksiginfo_init(&ksi);
  443         ksi.ksi_signo = uap->sig;
  444         ksi.ksi_code = SI_LWP;
  445         ksi.ksi_pid = td->td_proc->p_pid;
  446         ksi.ksi_uid = td->td_ucred->cr_ruid;
  447         if (uap->id == -1) {
  448                 if ((p = pfind(uap->pid)) == NULL)
  449                         return (ESRCH);
  450                 AUDIT_ARG_PROCESS(p);
  451                 error = p_cansignal(td, p, uap->sig);
  452                 if (error) {
  453                         PROC_UNLOCK(p);
  454                         return (error);
  455                 }
  456                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  457                         error = EINVAL;
  458                 } else {
  459                         error = ESRCH;
  460                         FOREACH_THREAD_IN_PROC(p, ttd) {
  461                                 if (ttd != td) {
  462                                         error = 0;
  463                                         if (uap->sig == 0)
  464                                                 break;
  465                                         tdksignal(ttd, uap->sig, &ksi);
  466                                 }
  467                         }
  468                 }
  469                 PROC_UNLOCK(p);
  470         } else {
  471                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  472                 if (ttd == NULL)
  473                         return (ESRCH);
  474                 p = ttd->td_proc;
  475                 AUDIT_ARG_PROCESS(p);
  476                 error = p_cansignal(td, p, uap->sig);
  477                 if (uap->sig == 0)
  478                         ;
  479                 else if (!_SIG_VALID(uap->sig))
  480                         error = EINVAL;
  481                 else
  482                         tdksignal(ttd, uap->sig, &ksi);
  483                 PROC_UNLOCK(p);
  484         }
  485         return (error);
  486 }
  487 
  488 int
  489 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  490         /* const struct timespec *timeout */
  491 {
  492         struct timespec ts, *tsp;
  493         int error;
  494 
  495         tsp = NULL;
  496         if (uap->timeout != NULL) {
  497                 error = umtx_copyin_timeout(uap->timeout, &ts);
  498                 if (error != 0)
  499                         return (error);
  500                 tsp = &ts;
  501         }
  502 
  503         return (kern_thr_suspend(td, tsp));
  504 }
  505 
  506 int
  507 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  508 {
  509         struct proc *p = td->td_proc;
  510         struct timeval tv;
  511         int error = 0;
  512         int timo = 0;
  513 
  514         if (td->td_pflags & TDP_WAKEUP) {
  515                 td->td_pflags &= ~TDP_WAKEUP;
  516                 return (0);
  517         }
  518 
  519         if (tsp != NULL) {
  520                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  521                         error = EWOULDBLOCK;
  522                 else {
  523                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  524                         timo = tvtohz(&tv);
  525                 }
  526         }
  527 
  528         PROC_LOCK(p);
  529         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  530                 error = msleep((void *)td, &p->p_mtx,
  531                          PCATCH, "lthr", timo);
  532 
  533         if (td->td_flags & TDF_THRWAKEUP) {
  534                 thread_lock(td);
  535                 td->td_flags &= ~TDF_THRWAKEUP;
  536                 thread_unlock(td);
  537                 PROC_UNLOCK(p);
  538                 return (0);
  539         }
  540         PROC_UNLOCK(p);
  541         if (error == EWOULDBLOCK)
  542                 error = ETIMEDOUT;
  543         else if (error == ERESTART) {
  544                 if (timo != 0)
  545                         error = EINTR;
  546         }
  547         return (error);
  548 }
  549 
  550 int
  551 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  552         /* long id */
  553 {
  554         struct proc *p;
  555         struct thread *ttd;
  556 
  557         if (uap->id == td->td_tid) {
  558                 td->td_pflags |= TDP_WAKEUP;
  559                 return (0);
  560         } 
  561 
  562         p = td->td_proc;
  563         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  564         if (ttd == NULL)
  565                 return (ESRCH);
  566         thread_lock(ttd);
  567         ttd->td_flags |= TDF_THRWAKEUP;
  568         thread_unlock(ttd);
  569         wakeup((void *)ttd);
  570         PROC_UNLOCK(p);
  571         return (0);
  572 }
  573 
  574 int
  575 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  576 {
  577         struct proc *p;
  578         char name[MAXCOMLEN + 1];
  579         struct thread *ttd;
  580         int error;
  581 
  582         error = 0;
  583         name[0] = '\0';
  584         if (uap->name != NULL) {
  585                 error = copyinstr(uap->name, name, sizeof(name), NULL);
  586                 if (error == ENAMETOOLONG) {
  587                         error = copyin(uap->name, name, sizeof(name) - 1);
  588                         name[sizeof(name) - 1] = '\0';
  589                 }
  590                 if (error)
  591                         return (error);
  592         }
  593         p = td->td_proc;
  594         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  595         if (ttd == NULL)
  596                 return (ESRCH);
  597         strcpy(ttd->td_name, name);
  598 #ifdef KTR
  599         sched_clear_tdname(ttd);
  600 #endif
  601         PROC_UNLOCK(p);
  602         return (error);
  603 }
  604 
  605 int
  606 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
  607 {
  608 
  609         /* Have race condition but it is cheap. */
  610         if (p->p_numthreads >= max_threads_per_proc) {
  611                 ++max_threads_hits;
  612                 return (EPROCLIM);
  613         }
  614 
  615         *ntd = thread_alloc(pages);
  616         if (*ntd == NULL)
  617                 return (ENOMEM);
  618 
  619         return (0);
  620 }
Cache object: da90865be8645bfe35524c40c281a5f3
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_thr.c

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