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/10.4/sys/kern/kern_thr.c 315949 2017-03-25 13:33:23Z badger $");
   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 <machine/frame.h>
   59 
   60 #include <security/audit/audit.h>
   61 
   62 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
   63     "thread allocation");
   64 
   65 static int max_threads_per_proc = 1500;
   66 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
   67     &max_threads_per_proc, 0, "Limit on threads per proc");
   68 
   69 static int max_threads_hits;
   70 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
   71     &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
   72 
   73 #ifdef COMPAT_FREEBSD32
   74 
   75 static inline int
   76 suword_lwpid(void *addr, lwpid_t lwpid)
   77 {
   78         int error;
   79 
   80         if (SV_CURPROC_FLAG(SV_LP64))
   81                 error = suword(addr, lwpid);
   82         else
   83                 error = suword32(addr, lwpid);
   84         return (error);
   85 }
   86 
   87 #else
   88 #define suword_lwpid    suword
   89 #endif
   90 
   91 /*
   92  * System call interface.
   93  */
   94 
   95 struct thr_create_initthr_args {
   96         ucontext_t ctx;
   97         long *tid;
   98 };
   99 
  100 static int
  101 thr_create_initthr(struct thread *td, void *thunk)
  102 {
  103         struct thr_create_initthr_args *args;
  104 
  105         /* Copy out the child tid. */
  106         args = thunk;
  107         if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
  108                 return (EFAULT);
  109 
  110         return (set_mcontext(td, &args->ctx.uc_mcontext));
  111 }
  112 
  113 int
  114 sys_thr_create(struct thread *td, struct thr_create_args *uap)
  115     /* ucontext_t *ctx, long *id, int flags */
  116 {
  117         struct thr_create_initthr_args args;
  118         int error;
  119 
  120         if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
  121                 return (error);
  122         args.tid = uap->id;
  123         return (thread_create(td, NULL, thr_create_initthr, &args));
  124 }
  125 
  126 int
  127 sys_thr_new(struct thread *td, struct thr_new_args *uap)
  128     /* struct thr_param * */
  129 {
  130         struct thr_param param;
  131         int error;
  132 
  133         if (uap->param_size < 0 || uap->param_size > sizeof(param))
  134                 return (EINVAL);
  135         bzero(&param, sizeof(param));
  136         if ((error = copyin(uap->param, &param, uap->param_size)))
  137                 return (error);
  138         return (kern_thr_new(td, &param));
  139 }
  140 
  141 static int
  142 thr_new_initthr(struct thread *td, void *thunk)
  143 {
  144         stack_t stack;
  145         struct thr_param *param;
  146 
  147         /*
  148          * Here we copy out tid to two places, one for child and one
  149          * for parent, because pthread can create a detached thread,
  150          * if parent wants to safely access child tid, it has to provide
  151          * its storage, because child thread may exit quickly and
  152          * memory is freed before parent thread can access it.
  153          */
  154         param = thunk;
  155         if ((param->child_tid != NULL &&
  156             suword_lwpid(param->child_tid, td->td_tid)) ||
  157             (param->parent_tid != NULL &&
  158             suword_lwpid(param->parent_tid, td->td_tid)))
  159                 return (EFAULT);
  160 
  161         /* Set up our machine context. */
  162         stack.ss_sp = param->stack_base;
  163         stack.ss_size = param->stack_size;
  164         /* Set upcall address to user thread entry function. */
  165         cpu_set_upcall_kse(td, param->start_func, param->arg, &stack);
  166         /* Setup user TLS address and TLS pointer register. */
  167         return (cpu_set_user_tls(td, param->tls_base));
  168 }
  169 
  170 int
  171 kern_thr_new(struct thread *td, struct thr_param *param)
  172 {
  173         struct rtprio rtp, *rtpp;
  174         int error;
  175 
  176         rtpp = NULL;
  177         if (param->rtp != 0) {
  178                 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
  179                 if (error)
  180                         return (error);
  181                 rtpp = &rtp;
  182         }
  183         return (thread_create(td, rtpp, thr_new_initthr, param));
  184 }
  185 
  186 int
  187 thread_create(struct thread *td, struct rtprio *rtp,
  188     int (*initialize_thread)(struct thread *, void *), void *thunk)
  189 {
  190         struct thread *newtd;
  191         struct proc *p;
  192         int error;
  193 
  194         p = td->td_proc;
  195 
  196         if (rtp != NULL) {
  197                 switch(rtp->type) {
  198                 case RTP_PRIO_REALTIME:
  199                 case RTP_PRIO_FIFO:
  200                         /* Only root can set scheduler policy */
  201                         if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
  202                                 return (EPERM);
  203                         if (rtp->prio > RTP_PRIO_MAX)
  204                                 return (EINVAL);
  205                         break;
  206                 case RTP_PRIO_NORMAL:
  207                         rtp->prio = 0;
  208                         break;
  209                 default:
  210                         return (EINVAL);
  211                 }
  212         }
  213 
  214 #ifdef RACCT
  215         PROC_LOCK(td->td_proc);
  216         error = racct_add(p, RACCT_NTHR, 1);
  217         PROC_UNLOCK(td->td_proc);
  218         if (error != 0)
  219                 return (EPROCLIM);
  220 #endif
  221 
  222         /* Initialize our td */
  223         error = kern_thr_alloc(p, 0, &newtd);
  224         if (error)
  225                 goto fail;
  226 
  227         cpu_set_upcall(newtd, td);
  228 
  229         bzero(&newtd->td_startzero,
  230             __rangeof(struct thread, td_startzero, td_endzero));
  231         newtd->td_su = NULL;
  232         newtd->td_sleeptimo = 0;
  233         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  234             __rangeof(struct thread, td_startcopy, td_endcopy));
  235         newtd->td_proc = td->td_proc;
  236         newtd->td_ucred = crhold(td->td_ucred);
  237         newtd->td_dbg_sc_code = td->td_dbg_sc_code;
  238         newtd->td_dbg_sc_narg = td->td_dbg_sc_narg;
  239 
  240         error = initialize_thread(newtd, thunk);
  241         if (error != 0) {
  242                 thread_free(newtd);
  243                 crfree(td->td_ucred);
  244                 goto fail;
  245         }
  246 
  247         PROC_LOCK(td->td_proc);
  248         td->td_proc->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_ptevents & PTRACE_LWP)
  258                 newtd->td_dbgflags |= TDB_BORN;
  259         PROC_UNLOCK(p);
  260 
  261         tidhash_add(newtd);
  262 
  263         thread_lock(newtd);
  264         if (rtp != NULL) {
  265                 if (!(td->td_pri_class == PRI_TIMESHARE &&
  266                       rtp->type == RTP_PRIO_NORMAL)) {
  267                         rtp_to_pri(rtp, newtd);
  268                         sched_prio(newtd, newtd->td_user_pri);
  269                 } /* ignore timesharing class */
  270         }
  271         TD_SET_CAN_RUN(newtd);
  272         sched_add(newtd, SRQ_BORING);
  273         thread_unlock(newtd);
  274 
  275         return (0);
  276 
  277 fail:
  278 #ifdef RACCT
  279         if (racct_enable) {
  280                 PROC_LOCK(p);
  281                 racct_sub(p, RACCT_NTHR, 1);
  282                 PROC_UNLOCK(p);
  283         }
  284 #endif
  285         return (error);
  286 }
  287 
  288 int
  289 sys_thr_self(struct thread *td, struct thr_self_args *uap)
  290     /* long *id */
  291 {
  292         int error;
  293 
  294         error = suword_lwpid(uap->id, (unsigned)td->td_tid);
  295         if (error == -1)
  296                 return (EFAULT);
  297         return (0);
  298 }
  299 
  300 int
  301 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
  302     /* long *state */
  303 {
  304 
  305         /* Signal userland that it can free the stack. */
  306         if ((void *)uap->state != NULL) {
  307                 suword_lwpid(uap->state, 1);
  308                 kern_umtx_wake(td, uap->state, INT_MAX, 0);
  309         }
  310 
  311         return (kern_thr_exit(td));
  312 }
  313 
  314 int
  315 kern_thr_exit(struct thread *td)
  316 {
  317         struct proc *p;
  318 
  319         p = td->td_proc;
  320 
  321         /*
  322          * If all of the threads in a process call this routine to
  323          * exit (e.g. all threads call pthread_exit()), exactly one
  324          * thread should return to the caller to terminate the process
  325          * instead of the thread.
  326          *
  327          * Checking p_numthreads alone is not sufficient since threads
  328          * might be committed to terminating while the PROC_LOCK is
  329          * dropped in either ptracestop() or while removing this thread
  330          * from the tidhash.  Instead, the p_pendingexits field holds
  331          * the count of threads in either of those states and a thread
  332          * is considered the "last" thread if all of the other threads
  333          * in a process are already terminating.
  334          */
  335         PROC_LOCK(p);
  336         if (p->p_numthreads == p->p_pendingexits + 1) {
  337                 /*
  338                  * Ignore attempts to shut down last thread in the
  339                  * proc.  This will actually call _exit(2) in the
  340                  * usermode trampoline when it returns.
  341                  */
  342                 PROC_UNLOCK(p);
  343                 return (0);
  344         }
  345 
  346         p->p_pendingexits++;
  347         td->td_dbgflags |= TDB_EXIT;
  348         if (p->p_ptevents & PTRACE_LWP)
  349                 ptracestop(td, SIGTRAP, NULL);
  350         PROC_UNLOCK(p);
  351         tidhash_remove(td);
  352         PROC_LOCK(p);
  353         p->p_pendingexits--;
  354 
  355         /*
  356          * The check above should prevent all other threads from this
  357          * process from exiting while the PROC_LOCK is dropped, so
  358          * there must be at least one other thread other than the
  359          * current thread.
  360          */
  361         KASSERT(p->p_numthreads > 1, ("too few threads"));
  362         racct_sub(p, RACCT_NTHR, 1);
  363         tdsigcleanup(td);
  364         umtx_thread_exit(td);
  365         PROC_SLOCK(p);
  366         thread_stopped(p);
  367         thread_exit();
  368         /* NOTREACHED */
  369 }
  370 
  371 int
  372 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  373     /* long id, int sig */
  374 {
  375         ksiginfo_t ksi;
  376         struct thread *ttd;
  377         struct proc *p;
  378         int error;
  379 
  380         p = td->td_proc;
  381         ksiginfo_init(&ksi);
  382         ksi.ksi_signo = uap->sig;
  383         ksi.ksi_code = SI_LWP;
  384         ksi.ksi_pid = p->p_pid;
  385         ksi.ksi_uid = td->td_ucred->cr_ruid;
  386         if (uap->id == -1) {
  387                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  388                         error = EINVAL;
  389                 } else {
  390                         error = ESRCH;
  391                         PROC_LOCK(p);
  392                         FOREACH_THREAD_IN_PROC(p, ttd) {
  393                                 if (ttd != td) {
  394                                         error = 0;
  395                                         if (uap->sig == 0)
  396                                                 break;
  397                                         tdksignal(ttd, uap->sig, &ksi);
  398                                 }
  399                         }
  400                         PROC_UNLOCK(p);
  401                 }
  402         } else {
  403                 error = 0;
  404                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  405                 if (ttd == NULL)
  406                         return (ESRCH);
  407                 if (uap->sig == 0)
  408                         ;
  409                 else if (!_SIG_VALID(uap->sig))
  410                         error = EINVAL;
  411                 else 
  412                         tdksignal(ttd, uap->sig, &ksi);
  413                 PROC_UNLOCK(ttd->td_proc);
  414         }
  415         return (error);
  416 }
  417 
  418 int
  419 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  420     /* pid_t pid, long id, int sig */
  421 {
  422         ksiginfo_t ksi;
  423         struct thread *ttd;
  424         struct proc *p;
  425         int error;
  426 
  427         AUDIT_ARG_SIGNUM(uap->sig);
  428 
  429         ksiginfo_init(&ksi);
  430         ksi.ksi_signo = uap->sig;
  431         ksi.ksi_code = SI_LWP;
  432         ksi.ksi_pid = td->td_proc->p_pid;
  433         ksi.ksi_uid = td->td_ucred->cr_ruid;
  434         if (uap->id == -1) {
  435                 if ((p = pfind(uap->pid)) == NULL)
  436                         return (ESRCH);
  437                 AUDIT_ARG_PROCESS(p);
  438                 error = p_cansignal(td, p, uap->sig);
  439                 if (error) {
  440                         PROC_UNLOCK(p);
  441                         return (error);
  442                 }
  443                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  444                         error = EINVAL;
  445                 } else {
  446                         error = ESRCH;
  447                         FOREACH_THREAD_IN_PROC(p, ttd) {
  448                                 if (ttd != td) {
  449                                         error = 0;
  450                                         if (uap->sig == 0)
  451                                                 break;
  452                                         tdksignal(ttd, uap->sig, &ksi);
  453                                 }
  454                         }
  455                 }
  456                 PROC_UNLOCK(p);
  457         } else {
  458                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  459                 if (ttd == NULL)
  460                         return (ESRCH);
  461                 p = ttd->td_proc;
  462                 AUDIT_ARG_PROCESS(p);
  463                 error = p_cansignal(td, p, uap->sig);
  464                 if (uap->sig == 0)
  465                         ;
  466                 else if (!_SIG_VALID(uap->sig))
  467                         error = EINVAL;
  468                 else
  469                         tdksignal(ttd, uap->sig, &ksi);
  470                 PROC_UNLOCK(p);
  471         }
  472         return (error);
  473 }
  474 
  475 int
  476 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  477         /* const struct timespec *timeout */
  478 {
  479         struct timespec ts, *tsp;
  480         int error;
  481 
  482         tsp = NULL;
  483         if (uap->timeout != NULL) {
  484                 error = umtx_copyin_timeout(uap->timeout, &ts);
  485                 if (error != 0)
  486                         return (error);
  487                 tsp = &ts;
  488         }
  489 
  490         return (kern_thr_suspend(td, tsp));
  491 }
  492 
  493 int
  494 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  495 {
  496         struct proc *p = td->td_proc;
  497         struct timeval tv;
  498         int error = 0;
  499         int timo = 0;
  500 
  501         if (td->td_pflags & TDP_WAKEUP) {
  502                 td->td_pflags &= ~TDP_WAKEUP;
  503                 return (0);
  504         }
  505 
  506         if (tsp != NULL) {
  507                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  508                         error = EWOULDBLOCK;
  509                 else {
  510                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  511                         timo = tvtohz(&tv);
  512                 }
  513         }
  514 
  515         PROC_LOCK(p);
  516         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  517                 error = msleep((void *)td, &p->p_mtx,
  518                          PCATCH, "lthr", timo);
  519 
  520         if (td->td_flags & TDF_THRWAKEUP) {
  521                 thread_lock(td);
  522                 td->td_flags &= ~TDF_THRWAKEUP;
  523                 thread_unlock(td);
  524                 PROC_UNLOCK(p);
  525                 return (0);
  526         }
  527         PROC_UNLOCK(p);
  528         if (error == EWOULDBLOCK)
  529                 error = ETIMEDOUT;
  530         else if (error == ERESTART) {
  531                 if (timo != 0)
  532                         error = EINTR;
  533         }
  534         return (error);
  535 }
  536 
  537 int
  538 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  539         /* long id */
  540 {
  541         struct proc *p;
  542         struct thread *ttd;
  543 
  544         if (uap->id == td->td_tid) {
  545                 td->td_pflags |= TDP_WAKEUP;
  546                 return (0);
  547         } 
  548 
  549         p = td->td_proc;
  550         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  551         if (ttd == NULL)
  552                 return (ESRCH);
  553         thread_lock(ttd);
  554         ttd->td_flags |= TDF_THRWAKEUP;
  555         thread_unlock(ttd);
  556         wakeup((void *)ttd);
  557         PROC_UNLOCK(p);
  558         return (0);
  559 }
  560 
  561 int
  562 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  563 {
  564         struct proc *p;
  565         char name[MAXCOMLEN + 1];
  566         struct thread *ttd;
  567         int error;
  568 
  569         error = 0;
  570         name[0] = '\0';
  571         if (uap->name != NULL) {
  572                 error = copyinstr(uap->name, name, sizeof(name), NULL);
  573                 if (error == ENAMETOOLONG) {
  574                         error = copyin(uap->name, name, sizeof(name) - 1);
  575                         name[sizeof(name) - 1] = '\0';
  576                 }
  577                 if (error)
  578                         return (error);
  579         }
  580         p = td->td_proc;
  581         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  582         if (ttd == NULL)
  583                 return (ESRCH);
  584         strcpy(ttd->td_name, name);
  585 #ifdef KTR
  586         sched_clear_tdname(ttd);
  587 #endif
  588         PROC_UNLOCK(p);
  589         return (error);
  590 }
  591 
  592 int
  593 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
  594 {
  595 
  596         /* Have race condition but it is cheap. */
  597         if (p->p_numthreads >= max_threads_per_proc) {
  598                 ++max_threads_hits;
  599                 return (EPROCLIM);
  600         }
  601 
  602         *ntd = thread_alloc(pages);
  603         if (*ntd == NULL)
  604                 return (ENOMEM);
  605 
  606         return (0);
  607 }

Cache object: f6ba5701c2ddc7b0d14a121ba68b0036


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