The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/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/10.2/sys/kern/kern_thr.c 284665 2015-06-21 06:28:26Z trasz $");
   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 <machine/frame.h>
   58 
   59 #include <security/audit/audit.h>
   60 
   61 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
   62     "thread allocation");
   63 
   64 static int max_threads_per_proc = 1500;
   65 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
   66     &max_threads_per_proc, 0, "Limit on threads per proc");
   67 
   68 static int max_threads_hits;
   69 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
   70     &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
   71 
   72 #ifdef COMPAT_FREEBSD32
   73 
   74 static inline int
   75 suword_lwpid(void *addr, lwpid_t lwpid)
   76 {
   77         int error;
   78 
   79         if (SV_CURPROC_FLAG(SV_LP64))
   80                 error = suword(addr, lwpid);
   81         else
   82                 error = suword32(addr, lwpid);
   83         return (error);
   84 }
   85 
   86 #else
   87 #define suword_lwpid    suword
   88 #endif
   89 
   90 static int create_thread(struct thread *td, mcontext_t *ctx,
   91                          void (*start_func)(void *), void *arg,
   92                          char *stack_base, size_t stack_size,
   93                          char *tls_base,
   94                          long *child_tid, long *parent_tid,
   95                          int flags, struct rtprio *rtp);
   96 
   97 /*
   98  * System call interface.
   99  */
  100 int
  101 sys_thr_create(struct thread *td, struct thr_create_args *uap)
  102     /* ucontext_t *ctx, long *id, int flags */
  103 {
  104         ucontext_t ctx;
  105         int error;
  106 
  107         if ((error = copyin(uap->ctx, &ctx, sizeof(ctx))))
  108                 return (error);
  109 
  110         error = create_thread(td, &ctx.uc_mcontext, NULL, NULL,
  111                 NULL, 0, NULL, uap->id, NULL, uap->flags, NULL);
  112         return (error);
  113 }
  114 
  115 int
  116 sys_thr_new(struct thread *td, struct thr_new_args *uap)
  117     /* struct thr_param * */
  118 {
  119         struct thr_param param;
  120         int error;
  121 
  122         if (uap->param_size < 0 || uap->param_size > sizeof(param))
  123                 return (EINVAL);
  124         bzero(&param, sizeof(param));
  125         if ((error = copyin(uap->param, &param, uap->param_size)))
  126                 return (error);
  127         return (kern_thr_new(td, &param));
  128 }
  129 
  130 int
  131 kern_thr_new(struct thread *td, struct thr_param *param)
  132 {
  133         struct rtprio rtp, *rtpp;
  134         int error;
  135 
  136         rtpp = NULL;
  137         if (param->rtp != 0) {
  138                 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
  139                 if (error)
  140                         return (error);
  141                 rtpp = &rtp;
  142         }
  143         error = create_thread(td, NULL, param->start_func, param->arg,
  144                 param->stack_base, param->stack_size, param->tls_base,
  145                 param->child_tid, param->parent_tid, param->flags,
  146                 rtpp);
  147         return (error);
  148 }
  149 
  150 static int
  151 create_thread(struct thread *td, mcontext_t *ctx,
  152             void (*start_func)(void *), void *arg,
  153             char *stack_base, size_t stack_size,
  154             char *tls_base,
  155             long *child_tid, long *parent_tid,
  156             int flags, struct rtprio *rtp)
  157 {
  158         stack_t stack;
  159         struct thread *newtd;
  160         struct proc *p;
  161         int error;
  162 
  163         p = td->td_proc;
  164 
  165         /* Have race condition but it is cheap. */
  166         if (p->p_numthreads >= max_threads_per_proc) {
  167                 ++max_threads_hits;
  168                 return (EPROCLIM);
  169         }
  170 
  171         if (rtp != NULL) {
  172                 switch(rtp->type) {
  173                 case RTP_PRIO_REALTIME:
  174                 case RTP_PRIO_FIFO:
  175                         /* Only root can set scheduler policy */
  176                         if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
  177                                 return (EPERM);
  178                         if (rtp->prio > RTP_PRIO_MAX)
  179                                 return (EINVAL);
  180                         break;
  181                 case RTP_PRIO_NORMAL:
  182                         rtp->prio = 0;
  183                         break;
  184                 default:
  185                         return (EINVAL);
  186                 }
  187         }
  188 
  189 #ifdef RACCT
  190         PROC_LOCK(td->td_proc);
  191         error = racct_add(p, RACCT_NTHR, 1);
  192         PROC_UNLOCK(td->td_proc);
  193         if (error != 0)
  194                 return (EPROCLIM);
  195 #endif
  196 
  197         /* Initialize our td */
  198         newtd = thread_alloc(0);
  199         if (newtd == NULL) {
  200                 error = ENOMEM;
  201                 goto fail;
  202         }
  203 
  204         cpu_set_upcall(newtd, td);
  205 
  206         /*
  207          * Try the copyout as soon as we allocate the td so we don't
  208          * have to tear things down in a failure case below.
  209          * Here we copy out tid to two places, one for child and one
  210          * for parent, because pthread can create a detached thread,
  211          * if parent wants to safely access child tid, it has to provide 
  212          * its storage, because child thread may exit quickly and
  213          * memory is freed before parent thread can access it.
  214          */
  215         if ((child_tid != NULL &&
  216             suword_lwpid(child_tid, newtd->td_tid)) ||
  217             (parent_tid != NULL &&
  218             suword_lwpid(parent_tid, newtd->td_tid))) {
  219                 thread_free(newtd);
  220                 error = EFAULT;
  221                 goto fail;
  222         }
  223 
  224         bzero(&newtd->td_startzero,
  225             __rangeof(struct thread, td_startzero, td_endzero));
  226         newtd->td_su = NULL;
  227         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  228             __rangeof(struct thread, td_startcopy, td_endcopy));
  229         newtd->td_proc = td->td_proc;
  230         newtd->td_ucred = crhold(td->td_ucred);
  231 
  232         if (ctx != NULL) { /* old way to set user context */
  233                 error = set_mcontext(newtd, ctx);
  234                 if (error != 0) {
  235                         thread_free(newtd);
  236                         crfree(td->td_ucred);
  237                         goto fail;
  238                 }
  239         } else {
  240                 /* Set up our machine context. */
  241                 stack.ss_sp = stack_base;
  242                 stack.ss_size = stack_size;
  243                 /* Set upcall address to user thread entry function. */
  244                 cpu_set_upcall_kse(newtd, start_func, arg, &stack);
  245                 /* Setup user TLS address and TLS pointer register. */
  246                 error = cpu_set_user_tls(newtd, tls_base);
  247                 if (error != 0) {
  248                         thread_free(newtd);
  249                         crfree(td->td_ucred);
  250                         goto fail;
  251                 }
  252         }
  253 
  254         PROC_LOCK(td->td_proc);
  255         td->td_proc->p_flag |= P_HADTHREADS;
  256         thread_link(newtd, p); 
  257         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  258         thread_lock(td);
  259         /* let the scheduler know about these things. */
  260         sched_fork_thread(td, newtd);
  261         thread_unlock(td);
  262         if (P_SHOULDSTOP(p))
  263                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  264         PROC_UNLOCK(p);
  265 
  266         tidhash_add(newtd);
  267 
  268         thread_lock(newtd);
  269         if (rtp != NULL) {
  270                 if (!(td->td_pri_class == PRI_TIMESHARE &&
  271                       rtp->type == RTP_PRIO_NORMAL)) {
  272                         rtp_to_pri(rtp, newtd);
  273                         sched_prio(newtd, newtd->td_user_pri);
  274                 } /* ignore timesharing class */
  275         }
  276         TD_SET_CAN_RUN(newtd);
  277         sched_add(newtd, SRQ_BORING);
  278         thread_unlock(newtd);
  279 
  280         return (0);
  281 
  282 fail:
  283 #ifdef RACCT
  284         if (racct_enable) {
  285                 PROC_LOCK(p);
  286                 racct_sub(p, RACCT_NTHR, 1);
  287                 PROC_UNLOCK(p);
  288         }
  289 #endif
  290         return (error);
  291 }
  292 
  293 int
  294 sys_thr_self(struct thread *td, struct thr_self_args *uap)
  295     /* long *id */
  296 {
  297         int error;
  298 
  299         error = suword_lwpid(uap->id, (unsigned)td->td_tid);
  300         if (error == -1)
  301                 return (EFAULT);
  302         return (0);
  303 }
  304 
  305 int
  306 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
  307     /* long *state */
  308 {
  309         struct proc *p;
  310 
  311         p = td->td_proc;
  312 
  313         /* Signal userland that it can free the stack. */
  314         if ((void *)uap->state != NULL) {
  315                 suword_lwpid(uap->state, 1);
  316                 kern_umtx_wake(td, uap->state, INT_MAX, 0);
  317         }
  318 
  319         rw_wlock(&tidhash_lock);
  320 
  321         PROC_LOCK(p);
  322 
  323         if (p->p_numthreads != 1) {
  324                 racct_sub(p, RACCT_NTHR, 1);
  325                 LIST_REMOVE(td, td_hash);
  326                 rw_wunlock(&tidhash_lock);
  327                 tdsigcleanup(td);
  328                 umtx_thread_exit(td);
  329                 PROC_SLOCK(p);
  330                 thread_stopped(p);
  331                 thread_exit();
  332                 /* NOTREACHED */
  333         }
  334 
  335         /*
  336          * Ignore attempts to shut down last thread in the proc.  This
  337          * will actually call _exit(2) in the usermode trampoline when
  338          * it returns.
  339          */
  340         PROC_UNLOCK(p);
  341         rw_wunlock(&tidhash_lock);
  342         return (0);
  343 }
  344 
  345 int
  346 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  347     /* long id, int sig */
  348 {
  349         ksiginfo_t ksi;
  350         struct thread *ttd;
  351         struct proc *p;
  352         int error;
  353 
  354         p = td->td_proc;
  355         ksiginfo_init(&ksi);
  356         ksi.ksi_signo = uap->sig;
  357         ksi.ksi_code = SI_LWP;
  358         ksi.ksi_pid = p->p_pid;
  359         ksi.ksi_uid = td->td_ucred->cr_ruid;
  360         if (uap->id == -1) {
  361                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  362                         error = EINVAL;
  363                 } else {
  364                         error = ESRCH;
  365                         PROC_LOCK(p);
  366                         FOREACH_THREAD_IN_PROC(p, ttd) {
  367                                 if (ttd != td) {
  368                                         error = 0;
  369                                         if (uap->sig == 0)
  370                                                 break;
  371                                         tdksignal(ttd, uap->sig, &ksi);
  372                                 }
  373                         }
  374                         PROC_UNLOCK(p);
  375                 }
  376         } else {
  377                 error = 0;
  378                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  379                 if (ttd == NULL)
  380                         return (ESRCH);
  381                 if (uap->sig == 0)
  382                         ;
  383                 else if (!_SIG_VALID(uap->sig))
  384                         error = EINVAL;
  385                 else 
  386                         tdksignal(ttd, uap->sig, &ksi);
  387                 PROC_UNLOCK(ttd->td_proc);
  388         }
  389         return (error);
  390 }
  391 
  392 int
  393 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  394     /* pid_t pid, long id, int sig */
  395 {
  396         ksiginfo_t ksi;
  397         struct thread *ttd;
  398         struct proc *p;
  399         int error;
  400 
  401         AUDIT_ARG_SIGNUM(uap->sig);
  402 
  403         ksiginfo_init(&ksi);
  404         ksi.ksi_signo = uap->sig;
  405         ksi.ksi_code = SI_LWP;
  406         ksi.ksi_pid = td->td_proc->p_pid;
  407         ksi.ksi_uid = td->td_ucred->cr_ruid;
  408         if (uap->id == -1) {
  409                 if ((p = pfind(uap->pid)) == NULL)
  410                         return (ESRCH);
  411                 AUDIT_ARG_PROCESS(p);
  412                 error = p_cansignal(td, p, uap->sig);
  413                 if (error) {
  414                         PROC_UNLOCK(p);
  415                         return (error);
  416                 }
  417                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  418                         error = EINVAL;
  419                 } else {
  420                         error = ESRCH;
  421                         FOREACH_THREAD_IN_PROC(p, ttd) {
  422                                 if (ttd != td) {
  423                                         error = 0;
  424                                         if (uap->sig == 0)
  425                                                 break;
  426                                         tdksignal(ttd, uap->sig, &ksi);
  427                                 }
  428                         }
  429                 }
  430                 PROC_UNLOCK(p);
  431         } else {
  432                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  433                 if (ttd == NULL)
  434                         return (ESRCH);
  435                 p = ttd->td_proc;
  436                 AUDIT_ARG_PROCESS(p);
  437                 error = p_cansignal(td, p, uap->sig);
  438                 if (uap->sig == 0)
  439                         ;
  440                 else if (!_SIG_VALID(uap->sig))
  441                         error = EINVAL;
  442                 else
  443                         tdksignal(ttd, uap->sig, &ksi);
  444                 PROC_UNLOCK(p);
  445         }
  446         return (error);
  447 }
  448 
  449 int
  450 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  451         /* const struct timespec *timeout */
  452 {
  453         struct timespec ts, *tsp;
  454         int error;
  455 
  456         tsp = NULL;
  457         if (uap->timeout != NULL) {
  458                 error = umtx_copyin_timeout(uap->timeout, &ts);
  459                 if (error != 0)
  460                         return (error);
  461                 tsp = &ts;
  462         }
  463 
  464         return (kern_thr_suspend(td, tsp));
  465 }
  466 
  467 int
  468 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  469 {
  470         struct proc *p = td->td_proc;
  471         struct timeval tv;
  472         int error = 0;
  473         int timo = 0;
  474 
  475         if (td->td_pflags & TDP_WAKEUP) {
  476                 td->td_pflags &= ~TDP_WAKEUP;
  477                 return (0);
  478         }
  479 
  480         if (tsp != NULL) {
  481                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  482                         error = EWOULDBLOCK;
  483                 else {
  484                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  485                         timo = tvtohz(&tv);
  486                 }
  487         }
  488 
  489         PROC_LOCK(p);
  490         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  491                 error = msleep((void *)td, &p->p_mtx,
  492                          PCATCH, "lthr", timo);
  493 
  494         if (td->td_flags & TDF_THRWAKEUP) {
  495                 thread_lock(td);
  496                 td->td_flags &= ~TDF_THRWAKEUP;
  497                 thread_unlock(td);
  498                 PROC_UNLOCK(p);
  499                 return (0);
  500         }
  501         PROC_UNLOCK(p);
  502         if (error == EWOULDBLOCK)
  503                 error = ETIMEDOUT;
  504         else if (error == ERESTART) {
  505                 if (timo != 0)
  506                         error = EINTR;
  507         }
  508         return (error);
  509 }
  510 
  511 int
  512 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  513         /* long id */
  514 {
  515         struct proc *p;
  516         struct thread *ttd;
  517 
  518         if (uap->id == td->td_tid) {
  519                 td->td_pflags |= TDP_WAKEUP;
  520                 return (0);
  521         } 
  522 
  523         p = td->td_proc;
  524         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  525         if (ttd == NULL)
  526                 return (ESRCH);
  527         thread_lock(ttd);
  528         ttd->td_flags |= TDF_THRWAKEUP;
  529         thread_unlock(ttd);
  530         wakeup((void *)ttd);
  531         PROC_UNLOCK(p);
  532         return (0);
  533 }
  534 
  535 int
  536 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  537 {
  538         struct proc *p;
  539         char name[MAXCOMLEN + 1];
  540         struct thread *ttd;
  541         int error;
  542 
  543         error = 0;
  544         name[0] = '\0';
  545         if (uap->name != NULL) {
  546                 error = copyinstr(uap->name, name, sizeof(name),
  547                         NULL);
  548                 if (error)
  549                         return (error);
  550         }
  551         p = td->td_proc;
  552         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  553         if (ttd == NULL)
  554                 return (ESRCH);
  555         strcpy(ttd->td_name, name);
  556 #ifdef KTR
  557         sched_clear_tdname(ttd);
  558 #endif
  559         PROC_UNLOCK(p);
  560         return (error);
  561 }

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