The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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: stable/10/sys/kern/kern_thr.c 337258 2018-08-03 14:45:53Z asomers $");
   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 
  366 #ifdef AUDIT
  367         AUDIT_SYSCALL_EXIT(0, td);
  368 #endif
  369 
  370         PROC_SLOCK(p);
  371         thread_stopped(p);
  372         thread_exit();
  373         /* NOTREACHED */
  374 }
  375 
  376 int
  377 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  378     /* long id, int sig */
  379 {
  380         ksiginfo_t ksi;
  381         struct thread *ttd;
  382         struct proc *p;
  383         int error;
  384 
  385         p = td->td_proc;
  386         ksiginfo_init(&ksi);
  387         ksi.ksi_signo = uap->sig;
  388         ksi.ksi_code = SI_LWP;
  389         ksi.ksi_pid = p->p_pid;
  390         ksi.ksi_uid = td->td_ucred->cr_ruid;
  391         if (uap->id == -1) {
  392                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  393                         error = EINVAL;
  394                 } else {
  395                         error = ESRCH;
  396                         PROC_LOCK(p);
  397                         FOREACH_THREAD_IN_PROC(p, ttd) {
  398                                 if (ttd != td) {
  399                                         error = 0;
  400                                         if (uap->sig == 0)
  401                                                 break;
  402                                         tdksignal(ttd, uap->sig, &ksi);
  403                                 }
  404                         }
  405                         PROC_UNLOCK(p);
  406                 }
  407         } else {
  408                 error = 0;
  409                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  410                 if (ttd == NULL)
  411                         return (ESRCH);
  412                 if (uap->sig == 0)
  413                         ;
  414                 else if (!_SIG_VALID(uap->sig))
  415                         error = EINVAL;
  416                 else 
  417                         tdksignal(ttd, uap->sig, &ksi);
  418                 PROC_UNLOCK(ttd->td_proc);
  419         }
  420         return (error);
  421 }
  422 
  423 int
  424 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  425     /* pid_t pid, long id, int sig */
  426 {
  427         ksiginfo_t ksi;
  428         struct thread *ttd;
  429         struct proc *p;
  430         int error;
  431 
  432         AUDIT_ARG_SIGNUM(uap->sig);
  433 
  434         ksiginfo_init(&ksi);
  435         ksi.ksi_signo = uap->sig;
  436         ksi.ksi_code = SI_LWP;
  437         ksi.ksi_pid = td->td_proc->p_pid;
  438         ksi.ksi_uid = td->td_ucred->cr_ruid;
  439         if (uap->id == -1) {
  440                 if ((p = pfind(uap->pid)) == NULL)
  441                         return (ESRCH);
  442                 AUDIT_ARG_PROCESS(p);
  443                 error = p_cansignal(td, p, uap->sig);
  444                 if (error) {
  445                         PROC_UNLOCK(p);
  446                         return (error);
  447                 }
  448                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  449                         error = EINVAL;
  450                 } else {
  451                         error = ESRCH;
  452                         FOREACH_THREAD_IN_PROC(p, ttd) {
  453                                 if (ttd != td) {
  454                                         error = 0;
  455                                         if (uap->sig == 0)
  456                                                 break;
  457                                         tdksignal(ttd, uap->sig, &ksi);
  458                                 }
  459                         }
  460                 }
  461                 PROC_UNLOCK(p);
  462         } else {
  463                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  464                 if (ttd == NULL)
  465                         return (ESRCH);
  466                 p = ttd->td_proc;
  467                 AUDIT_ARG_PROCESS(p);
  468                 error = p_cansignal(td, p, uap->sig);
  469                 if (uap->sig == 0)
  470                         ;
  471                 else if (!_SIG_VALID(uap->sig))
  472                         error = EINVAL;
  473                 else
  474                         tdksignal(ttd, uap->sig, &ksi);
  475                 PROC_UNLOCK(p);
  476         }
  477         return (error);
  478 }
  479 
  480 int
  481 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  482         /* const struct timespec *timeout */
  483 {
  484         struct timespec ts, *tsp;
  485         int error;
  486 
  487         tsp = NULL;
  488         if (uap->timeout != NULL) {
  489                 error = umtx_copyin_timeout(uap->timeout, &ts);
  490                 if (error != 0)
  491                         return (error);
  492                 tsp = &ts;
  493         }
  494 
  495         return (kern_thr_suspend(td, tsp));
  496 }
  497 
  498 int
  499 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  500 {
  501         struct proc *p = td->td_proc;
  502         struct timeval tv;
  503         int error = 0;
  504         int timo = 0;
  505 
  506         if (td->td_pflags & TDP_WAKEUP) {
  507                 td->td_pflags &= ~TDP_WAKEUP;
  508                 return (0);
  509         }
  510 
  511         if (tsp != NULL) {
  512                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  513                         error = EWOULDBLOCK;
  514                 else {
  515                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  516                         timo = tvtohz(&tv);
  517                 }
  518         }
  519 
  520         PROC_LOCK(p);
  521         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  522                 error = msleep((void *)td, &p->p_mtx,
  523                          PCATCH, "lthr", timo);
  524 
  525         if (td->td_flags & TDF_THRWAKEUP) {
  526                 thread_lock(td);
  527                 td->td_flags &= ~TDF_THRWAKEUP;
  528                 thread_unlock(td);
  529                 PROC_UNLOCK(p);
  530                 return (0);
  531         }
  532         PROC_UNLOCK(p);
  533         if (error == EWOULDBLOCK)
  534                 error = ETIMEDOUT;
  535         else if (error == ERESTART) {
  536                 if (timo != 0)
  537                         error = EINTR;
  538         }
  539         return (error);
  540 }
  541 
  542 int
  543 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  544         /* long id */
  545 {
  546         struct proc *p;
  547         struct thread *ttd;
  548 
  549         if (uap->id == td->td_tid) {
  550                 td->td_pflags |= TDP_WAKEUP;
  551                 return (0);
  552         } 
  553 
  554         p = td->td_proc;
  555         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  556         if (ttd == NULL)
  557                 return (ESRCH);
  558         thread_lock(ttd);
  559         ttd->td_flags |= TDF_THRWAKEUP;
  560         thread_unlock(ttd);
  561         wakeup((void *)ttd);
  562         PROC_UNLOCK(p);
  563         return (0);
  564 }
  565 
  566 int
  567 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  568 {
  569         struct proc *p;
  570         char name[MAXCOMLEN + 1];
  571         struct thread *ttd;
  572         int error;
  573 
  574         error = 0;
  575         name[0] = '\0';
  576         if (uap->name != NULL) {
  577                 error = copyinstr(uap->name, name, sizeof(name), NULL);
  578                 if (error == ENAMETOOLONG) {
  579                         error = copyin(uap->name, name, sizeof(name) - 1);
  580                         name[sizeof(name) - 1] = '\0';
  581                 }
  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: a116a23ac40b2d5660c7a4cbb057b278


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