kern_thr.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2003, Jeffrey Roberson <jeff@freebsd.org>
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice unmodified, this list of conditions, and the following
   12  *    disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD: releng/12.0/sys/kern/kern_thr.c 336205 2018-07-11 19:38:42Z asomers $");
   31 
   32 #include "opt_posix.h"
   33 #include "opt_hwpmc_hooks.h"
   34 #include <sys/param.h>
   35 #include <sys/kernel.h>
   36 #include <sys/lock.h>
   37 #include <sys/mutex.h>
   38 #include <sys/priv.h>
   39 #include <sys/proc.h>
   40 #include <sys/posix4.h>
   41 #include <sys/ptrace.h>
   42 #include <sys/racct.h>
   43 #include <sys/resourcevar.h>
   44 #include <sys/rwlock.h>
   45 #include <sys/sched.h>
   46 #include <sys/sysctl.h>
   47 #include <sys/smp.h>
   48 #include <sys/syscallsubr.h>
   49 #include <sys/sysent.h>
   50 #include <sys/systm.h>
   51 #include <sys/sysproto.h>
   52 #include <sys/signalvar.h>
   53 #include <sys/sysctl.h>
   54 #include <sys/ucontext.h>
   55 #include <sys/thr.h>
   56 #include <sys/rtprio.h>
   57 #include <sys/umtx.h>
   58 #include <sys/limits.h>
   59 #ifdef  HWPMC_HOOKS
   60 #include <sys/pmckern.h>
   61 #endif
   62 
   63 #include <machine/frame.h>
   64 
   65 #include <security/audit/audit.h>
   66 
   67 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
   68     "thread allocation");
   69 
   70 static int max_threads_per_proc = 1500;
   71 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
   72     &max_threads_per_proc, 0, "Limit on threads per proc");
   73 
   74 static int max_threads_hits;
   75 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
   76     &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
   77 
   78 #ifdef COMPAT_FREEBSD32
   79 
   80 static inline int
   81 suword_lwpid(void *addr, lwpid_t lwpid)
   82 {
   83         int error;
   84 
   85         if (SV_CURPROC_FLAG(SV_LP64))
   86                 error = suword(addr, lwpid);
   87         else
   88                 error = suword32(addr, lwpid);
   89         return (error);
   90 }
   91 
   92 #else
   93 #define suword_lwpid    suword
   94 #endif
   95 
   96 /*
   97  * System call interface.
   98  */
   99 
  100 struct thr_create_initthr_args {
  101         ucontext_t ctx;
  102         long *tid;
  103 };
  104 
  105 static int
  106 thr_create_initthr(struct thread *td, void *thunk)
  107 {
  108         struct thr_create_initthr_args *args;
  109 
  110         /* Copy out the child tid. */
  111         args = thunk;
  112         if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
  113                 return (EFAULT);
  114 
  115         return (set_mcontext(td, &args->ctx.uc_mcontext));
  116 }
  117 
  118 int
  119 sys_thr_create(struct thread *td, struct thr_create_args *uap)
  120     /* ucontext_t *ctx, long *id, int flags */
  121 {
  122         struct thr_create_initthr_args args;
  123         int error;
  124 
  125         if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
  126                 return (error);
  127         args.tid = uap->id;
  128         return (thread_create(td, NULL, thr_create_initthr, &args));
  129 }
  130 
  131 int
  132 sys_thr_new(struct thread *td, struct thr_new_args *uap)
  133     /* struct thr_param * */
  134 {
  135         struct thr_param param;
  136         int error;
  137 
  138         if (uap->param_size < 0 || uap->param_size > sizeof(param))
  139                 return (EINVAL);
  140         bzero(&param, sizeof(param));
  141         if ((error = copyin(uap->param, &param, uap->param_size)))
  142                 return (error);
  143         return (kern_thr_new(td, &param));
  144 }
  145 
  146 static int
  147 thr_new_initthr(struct thread *td, void *thunk)
  148 {
  149         stack_t stack;
  150         struct thr_param *param;
  151 
  152         /*
  153          * Here we copy out tid to two places, one for child and one
  154          * for parent, because pthread can create a detached thread,
  155          * if parent wants to safely access child tid, it has to provide
  156          * its storage, because child thread may exit quickly and
  157          * memory is freed before parent thread can access it.
  158          */
  159         param = thunk;
  160         if ((param->child_tid != NULL &&
  161             suword_lwpid(param->child_tid, td->td_tid)) ||
  162             (param->parent_tid != NULL &&
  163             suword_lwpid(param->parent_tid, td->td_tid)))
  164                 return (EFAULT);
  165 
  166         /* Set up our machine context. */
  167         stack.ss_sp = param->stack_base;
  168         stack.ss_size = param->stack_size;
  169         /* Set upcall address to user thread entry function. */
  170         cpu_set_upcall(td, param->start_func, param->arg, &stack);
  171         /* Setup user TLS address and TLS pointer register. */
  172         return (cpu_set_user_tls(td, param->tls_base));
  173 }
  174 
  175 int
  176 kern_thr_new(struct thread *td, struct thr_param *param)
  177 {
  178         struct rtprio rtp, *rtpp;
  179         int error;
  180 
  181         rtpp = NULL;
  182         if (param->rtp != 0) {
  183                 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
  184                 if (error)
  185                         return (error);
  186                 rtpp = &rtp;
  187         }
  188         return (thread_create(td, rtpp, thr_new_initthr, param));
  189 }
  190 
  191 int
  192 thread_create(struct thread *td, struct rtprio *rtp,
  193     int (*initialize_thread)(struct thread *, void *), void *thunk)
  194 {
  195         struct thread *newtd;
  196         struct proc *p;
  197         int error;
  198 
  199         p = td->td_proc;
  200 
  201         if (rtp != NULL) {
  202                 switch(rtp->type) {
  203                 case RTP_PRIO_REALTIME:
  204                 case RTP_PRIO_FIFO:
  205                         /* Only root can set scheduler policy */
  206                         if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
  207                                 return (EPERM);
  208                         if (rtp->prio > RTP_PRIO_MAX)
  209                                 return (EINVAL);
  210                         break;
  211                 case RTP_PRIO_NORMAL:
  212                         rtp->prio = 0;
  213                         break;
  214                 default:
  215                         return (EINVAL);
  216                 }
  217         }
  218 
  219 #ifdef RACCT
  220         if (racct_enable) {
  221                 PROC_LOCK(p);
  222                 error = racct_add(p, RACCT_NTHR, 1);
  223                 PROC_UNLOCK(p);
  224                 if (error != 0)
  225                         return (EPROCLIM);
  226         }
  227 #endif
  228 
  229         /* Initialize our td */
  230         error = kern_thr_alloc(p, 0, &newtd);
  231         if (error)
  232                 goto fail;
  233 
  234         cpu_copy_thread(newtd, td);
  235 
  236         bzero(&newtd->td_startzero,
  237             __rangeof(struct thread, td_startzero, td_endzero));
  238         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  239             __rangeof(struct thread, td_startcopy, td_endcopy));
  240         newtd->td_proc = td->td_proc;
  241         newtd->td_rb_list = newtd->td_rbp_list = newtd->td_rb_inact = 0;
  242         thread_cow_get(newtd, td);
  243 
  244         error = initialize_thread(newtd, thunk);
  245         if (error != 0) {
  246                 thread_cow_free(newtd);
  247                 thread_free(newtd);
  248                 goto fail;
  249         }
  250 
  251         PROC_LOCK(p);
  252         p->p_flag |= P_HADTHREADS;
  253         thread_link(newtd, p);
  254         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  255         thread_lock(td);
  256         /* let the scheduler know about these things. */
  257         sched_fork_thread(td, newtd);
  258         thread_unlock(td);
  259         if (P_SHOULDSTOP(p))
  260                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  261         if (p->p_ptevents & PTRACE_LWP)
  262                 newtd->td_dbgflags |= TDB_BORN;
  263 
  264         PROC_UNLOCK(p);
  265 #ifdef  HWPMC_HOOKS
  266         if (PMC_PROC_IS_USING_PMCS(p))
  267                 PMC_CALL_HOOK(newtd, PMC_FN_THR_CREATE, NULL);
  268         else if (PMC_SYSTEM_SAMPLING_ACTIVE())
  269                 PMC_CALL_HOOK_UNLOCKED(newtd, PMC_FN_THR_CREATE_LOG, NULL);
  270 #endif
  271 
  272         tidhash_add(newtd);
  273 
  274         thread_lock(newtd);
  275         if (rtp != NULL) {
  276                 if (!(td->td_pri_class == PRI_TIMESHARE &&
  277                       rtp->type == RTP_PRIO_NORMAL)) {
  278                         rtp_to_pri(rtp, newtd);
  279                         sched_prio(newtd, newtd->td_user_pri);
  280                 } /* ignore timesharing class */
  281         }
  282         TD_SET_CAN_RUN(newtd);
  283         sched_add(newtd, SRQ_BORING);
  284         thread_unlock(newtd);
  285 
  286         return (0);
  287 
  288 fail:
  289 #ifdef RACCT
  290         if (racct_enable) {
  291                 PROC_LOCK(p);
  292                 racct_sub(p, RACCT_NTHR, 1);
  293                 PROC_UNLOCK(p);
  294         }
  295 #endif
  296         return (error);
  297 }
  298 
  299 int
  300 sys_thr_self(struct thread *td, struct thr_self_args *uap)
  301     /* long *id */
  302 {
  303         int error;
  304 
  305         error = suword_lwpid(uap->id, (unsigned)td->td_tid);
  306         if (error == -1)
  307                 return (EFAULT);
  308         return (0);
  309 }
  310 
  311 int
  312 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
  313     /* long *state */
  314 {
  315 
  316         umtx_thread_exit(td);
  317 
  318         /* Signal userland that it can free the stack. */
  319         if ((void *)uap->state != NULL) {
  320                 suword_lwpid(uap->state, 1);
  321                 kern_umtx_wake(td, uap->state, INT_MAX, 0);
  322         }
  323 
  324         return (kern_thr_exit(td));
  325 }
  326 
  327 int
  328 kern_thr_exit(struct thread *td)
  329 {
  330         struct proc *p;
  331 
  332         p = td->td_proc;
  333 
  334         /*
  335          * If all of the threads in a process call this routine to
  336          * exit (e.g. all threads call pthread_exit()), exactly one
  337          * thread should return to the caller to terminate the process
  338          * instead of the thread.
  339          *
  340          * Checking p_numthreads alone is not sufficient since threads
  341          * might be committed to terminating while the PROC_LOCK is
  342          * dropped in either ptracestop() or while removing this thread
  343          * from the tidhash.  Instead, the p_pendingexits field holds
  344          * the count of threads in either of those states and a thread
  345          * is considered the "last" thread if all of the other threads
  346          * in a process are already terminating.
  347          */
  348         PROC_LOCK(p);
  349         if (p->p_numthreads == p->p_pendingexits + 1) {
  350                 /*
  351                  * Ignore attempts to shut down last thread in the
  352                  * proc.  This will actually call _exit(2) in the
  353                  * usermode trampoline when it returns.
  354                  */
  355                 PROC_UNLOCK(p);
  356                 return (0);
  357         }
  358 
  359         p->p_pendingexits++;
  360         td->td_dbgflags |= TDB_EXIT;
  361         if (p->p_ptevents & PTRACE_LWP)
  362                 ptracestop(td, SIGTRAP, NULL);
  363         PROC_UNLOCK(p);
  364         tidhash_remove(td);
  365         PROC_LOCK(p);
  366         p->p_pendingexits--;
  367 
  368         /*
  369          * The check above should prevent all other threads from this
  370          * process from exiting while the PROC_LOCK is dropped, so
  371          * there must be at least one other thread other than the
  372          * current thread.
  373          */
  374         KASSERT(p->p_numthreads > 1, ("too few threads"));
  375         racct_sub(p, RACCT_NTHR, 1);
  376         tdsigcleanup(td);
  377 
  378 #ifdef AUDIT
  379         AUDIT_SYSCALL_EXIT(0, td);
  380 #endif
  381 
  382         PROC_SLOCK(p);
  383         thread_stopped(p);
  384         thread_exit();
  385         /* NOTREACHED */
  386 }
  387 
  388 int
  389 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  390     /* long id, int sig */
  391 {
  392         ksiginfo_t ksi;
  393         struct thread *ttd;
  394         struct proc *p;
  395         int error;
  396 
  397         p = td->td_proc;
  398         ksiginfo_init(&ksi);
  399         ksi.ksi_signo = uap->sig;
  400         ksi.ksi_code = SI_LWP;
  401         ksi.ksi_pid = p->p_pid;
  402         ksi.ksi_uid = td->td_ucred->cr_ruid;
  403         if (uap->id == -1) {
  404                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  405                         error = EINVAL;
  406                 } else {
  407                         error = ESRCH;
  408                         PROC_LOCK(p);
  409                         FOREACH_THREAD_IN_PROC(p, ttd) {
  410                                 if (ttd != td) {
  411                                         error = 0;
  412                                         if (uap->sig == 0)
  413                                                 break;
  414                                         tdksignal(ttd, uap->sig, &ksi);
  415                                 }
  416                         }
  417                         PROC_UNLOCK(p);
  418                 }
  419         } else {
  420                 error = 0;
  421                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  422                 if (ttd == NULL)
  423                         return (ESRCH);
  424                 if (uap->sig == 0)
  425                         ;
  426                 else if (!_SIG_VALID(uap->sig))
  427                         error = EINVAL;
  428                 else 
  429                         tdksignal(ttd, uap->sig, &ksi);
  430                 PROC_UNLOCK(ttd->td_proc);
  431         }
  432         return (error);
  433 }
  434 
  435 int
  436 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  437     /* pid_t pid, long id, int sig */
  438 {
  439         ksiginfo_t ksi;
  440         struct thread *ttd;
  441         struct proc *p;
  442         int error;
  443 
  444         AUDIT_ARG_SIGNUM(uap->sig);
  445 
  446         ksiginfo_init(&ksi);
  447         ksi.ksi_signo = uap->sig;
  448         ksi.ksi_code = SI_LWP;
  449         ksi.ksi_pid = td->td_proc->p_pid;
  450         ksi.ksi_uid = td->td_ucred->cr_ruid;
  451         if (uap->id == -1) {
  452                 if ((p = pfind(uap->pid)) == NULL)
  453                         return (ESRCH);
  454                 AUDIT_ARG_PROCESS(p);
  455                 error = p_cansignal(td, p, uap->sig);
  456                 if (error) {
  457                         PROC_UNLOCK(p);
  458                         return (error);
  459                 }
  460                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  461                         error = EINVAL;
  462                 } else {
  463                         error = ESRCH;
  464                         FOREACH_THREAD_IN_PROC(p, ttd) {
  465                                 if (ttd != td) {
  466                                         error = 0;
  467                                         if (uap->sig == 0)
  468                                                 break;
  469                                         tdksignal(ttd, uap->sig, &ksi);
  470                                 }
  471                         }
  472                 }
  473                 PROC_UNLOCK(p);
  474         } else {
  475                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  476                 if (ttd == NULL)
  477                         return (ESRCH);
  478                 p = ttd->td_proc;
  479                 AUDIT_ARG_PROCESS(p);
  480                 error = p_cansignal(td, p, uap->sig);
  481                 if (uap->sig == 0)
  482                         ;
  483                 else if (!_SIG_VALID(uap->sig))
  484                         error = EINVAL;
  485                 else
  486                         tdksignal(ttd, uap->sig, &ksi);
  487                 PROC_UNLOCK(p);
  488         }
  489         return (error);
  490 }
  491 
  492 int
  493 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  494         /* const struct timespec *timeout */
  495 {
  496         struct timespec ts, *tsp;
  497         int error;
  498 
  499         tsp = NULL;
  500         if (uap->timeout != NULL) {
  501                 error = umtx_copyin_timeout(uap->timeout, &ts);
  502                 if (error != 0)
  503                         return (error);
  504                 tsp = &ts;
  505         }
  506 
  507         return (kern_thr_suspend(td, tsp));
  508 }
  509 
  510 int
  511 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  512 {
  513         struct proc *p = td->td_proc;
  514         struct timeval tv;
  515         int error = 0;
  516         int timo = 0;
  517 
  518         if (td->td_pflags & TDP_WAKEUP) {
  519                 td->td_pflags &= ~TDP_WAKEUP;
  520                 return (0);
  521         }
  522 
  523         if (tsp != NULL) {
  524                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  525                         error = EWOULDBLOCK;
  526                 else {
  527                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  528                         timo = tvtohz(&tv);
  529                 }
  530         }
  531 
  532         PROC_LOCK(p);
  533         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  534                 error = msleep((void *)td, &p->p_mtx,
  535                          PCATCH, "lthr", timo);
  536 
  537         if (td->td_flags & TDF_THRWAKEUP) {
  538                 thread_lock(td);
  539                 td->td_flags &= ~TDF_THRWAKEUP;
  540                 thread_unlock(td);
  541                 PROC_UNLOCK(p);
  542                 return (0);
  543         }
  544         PROC_UNLOCK(p);
  545         if (error == EWOULDBLOCK)
  546                 error = ETIMEDOUT;
  547         else if (error == ERESTART) {
  548                 if (timo != 0)
  549                         error = EINTR;
  550         }
  551         return (error);
  552 }
  553 
  554 int
  555 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  556         /* long id */
  557 {
  558         struct proc *p;
  559         struct thread *ttd;
  560 
  561         if (uap->id == td->td_tid) {
  562                 td->td_pflags |= TDP_WAKEUP;
  563                 return (0);
  564         } 
  565 
  566         p = td->td_proc;
  567         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  568         if (ttd == NULL)
  569                 return (ESRCH);
  570         thread_lock(ttd);
  571         ttd->td_flags |= TDF_THRWAKEUP;
  572         thread_unlock(ttd);
  573         wakeup((void *)ttd);
  574         PROC_UNLOCK(p);
  575         return (0);
  576 }
  577 
  578 int
  579 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  580 {
  581         struct proc *p;
  582         char name[MAXCOMLEN + 1];
  583         struct thread *ttd;
  584         int error;
  585 
  586         error = 0;
  587         name[0] = '\0';
  588         if (uap->name != NULL) {
  589                 error = copyinstr(uap->name, name, sizeof(name), NULL);
  590                 if (error == ENAMETOOLONG) {
  591                         error = copyin(uap->name, name, sizeof(name) - 1);
  592                         name[sizeof(name) - 1] = '\0';
  593                 }
  594                 if (error)
  595                         return (error);
  596         }
  597         p = td->td_proc;
  598         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  599         if (ttd == NULL)
  600                 return (ESRCH);
  601         strcpy(ttd->td_name, name);
  602 #ifdef HWPMC_HOOKS
  603         if (PMC_PROC_IS_USING_PMCS(p) || PMC_SYSTEM_SAMPLING_ACTIVE())
  604                 PMC_CALL_HOOK_UNLOCKED(ttd, PMC_FN_THR_CREATE_LOG, NULL);
  605 #endif
  606 #ifdef KTR
  607         sched_clear_tdname(ttd);
  608 #endif
  609         PROC_UNLOCK(p);
  610         return (error);
  611 }
  612 
  613 int
  614 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
  615 {
  616 
  617         /* Have race condition but it is cheap. */
  618         if (p->p_numthreads >= max_threads_per_proc) {
  619                 ++max_threads_hits;
  620                 return (EPROCLIM);
  621         }
  622 
  623         *ntd = thread_alloc(pages);
  624         if (*ntd == NULL)
  625                 return (ENOMEM);
  626 
  627         return (0);
  628 }
Cache object: a2e5213b6c256e863071ecdf41a1c175
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This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.
FreeBSD/Linux Kernel Cross Reference sys/kern/kern_thr.c

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