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/11.1/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 <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         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  237             __rangeof(struct thread, td_startcopy, td_endcopy));
  238         newtd->td_proc = td->td_proc;
  239         newtd->td_rb_list = newtd->td_rbp_list = newtd->td_rb_inact = 0;
  240         thread_cow_get(newtd, td);
  241 
  242         error = initialize_thread(newtd, thunk);
  243         if (error != 0) {
  244                 thread_cow_free(newtd);
  245                 thread_free(newtd);
  246                 goto fail;
  247         }
  248 
  249         PROC_LOCK(p);
  250         p->p_flag |= P_HADTHREADS;
  251         thread_link(newtd, p);
  252         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  253         thread_lock(td);
  254         /* let the scheduler know about these things. */
  255         sched_fork_thread(td, newtd);
  256         thread_unlock(td);
  257         if (P_SHOULDSTOP(p))
  258                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  259         if (p->p_ptevents & PTRACE_LWP)
  260                 newtd->td_dbgflags |= TDB_BORN;
  261 
  262         /*
  263          * Copy the existing thread VM policy into the new thread.
  264          */
  265         vm_domain_policy_localcopy(&newtd->td_vm_dom_policy,
  266             &td->td_vm_dom_policy);
  267 
  268         PROC_UNLOCK(p);
  269 
  270         tidhash_add(newtd);
  271 
  272         thread_lock(newtd);
  273         if (rtp != NULL) {
  274                 if (!(td->td_pri_class == PRI_TIMESHARE &&
  275                       rtp->type == RTP_PRIO_NORMAL)) {
  276                         rtp_to_pri(rtp, newtd);
  277                         sched_prio(newtd, newtd->td_user_pri);
  278                 } /* ignore timesharing class */
  279         }
  280         TD_SET_CAN_RUN(newtd);
  281         sched_add(newtd, SRQ_BORING);
  282         thread_unlock(newtd);
  283 
  284         return (0);
  285 
  286 fail:
  287 #ifdef RACCT
  288         if (racct_enable) {
  289                 PROC_LOCK(p);
  290                 racct_sub(p, RACCT_NTHR, 1);
  291                 PROC_UNLOCK(p);
  292         }
  293 #endif
  294         return (error);
  295 }
  296 
  297 int
  298 sys_thr_self(struct thread *td, struct thr_self_args *uap)
  299     /* long *id */
  300 {
  301         int error;
  302 
  303         error = suword_lwpid(uap->id, (unsigned)td->td_tid);
  304         if (error == -1)
  305                 return (EFAULT);
  306         return (0);
  307 }
  308 
  309 int
  310 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
  311     /* long *state */
  312 {
  313 
  314         umtx_thread_exit(td);
  315 
  316         /* Signal userland that it can free the stack. */
  317         if ((void *)uap->state != NULL) {
  318                 suword_lwpid(uap->state, 1);
  319                 kern_umtx_wake(td, uap->state, INT_MAX, 0);
  320         }
  321 
  322         return (kern_thr_exit(td));
  323 }
  324 
  325 int
  326 kern_thr_exit(struct thread *td)
  327 {
  328         struct proc *p;
  329 
  330         p = td->td_proc;
  331 
  332         /*
  333          * If all of the threads in a process call this routine to
  334          * exit (e.g. all threads call pthread_exit()), exactly one
  335          * thread should return to the caller to terminate the process
  336          * instead of the thread.
  337          *
  338          * Checking p_numthreads alone is not sufficient since threads
  339          * might be committed to terminating while the PROC_LOCK is
  340          * dropped in either ptracestop() or while removing this thread
  341          * from the tidhash.  Instead, the p_pendingexits field holds
  342          * the count of threads in either of those states and a thread
  343          * is considered the "last" thread if all of the other threads
  344          * in a process are already terminating.
  345          */
  346         PROC_LOCK(p);
  347         if (p->p_numthreads == p->p_pendingexits + 1) {
  348                 /*
  349                  * Ignore attempts to shut down last thread in the
  350                  * proc.  This will actually call _exit(2) in the
  351                  * usermode trampoline when it returns.
  352                  */
  353                 PROC_UNLOCK(p);
  354                 return (0);
  355         }
  356 
  357         p->p_pendingexits++;
  358         td->td_dbgflags |= TDB_EXIT;
  359         if (p->p_ptevents & PTRACE_LWP)
  360                 ptracestop(td, SIGTRAP, NULL);
  361         PROC_UNLOCK(p);
  362         tidhash_remove(td);
  363         PROC_LOCK(p);
  364         p->p_pendingexits--;
  365 
  366         /*
  367          * The check above should prevent all other threads from this
  368          * process from exiting while the PROC_LOCK is dropped, so
  369          * there must be at least one other thread other than the
  370          * current thread.
  371          */
  372         KASSERT(p->p_numthreads > 1, ("too few threads"));
  373         racct_sub(p, RACCT_NTHR, 1);
  374         tdsigcleanup(td);
  375         PROC_SLOCK(p);
  376         thread_stopped(p);
  377         thread_exit();
  378         /* NOTREACHED */
  379 }
  380 
  381 int
  382 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
  383     /* long id, int sig */
  384 {
  385         ksiginfo_t ksi;
  386         struct thread *ttd;
  387         struct proc *p;
  388         int error;
  389 
  390         p = td->td_proc;
  391         ksiginfo_init(&ksi);
  392         ksi.ksi_signo = uap->sig;
  393         ksi.ksi_code = SI_LWP;
  394         ksi.ksi_pid = p->p_pid;
  395         ksi.ksi_uid = td->td_ucred->cr_ruid;
  396         if (uap->id == -1) {
  397                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  398                         error = EINVAL;
  399                 } else {
  400                         error = ESRCH;
  401                         PROC_LOCK(p);
  402                         FOREACH_THREAD_IN_PROC(p, ttd) {
  403                                 if (ttd != td) {
  404                                         error = 0;
  405                                         if (uap->sig == 0)
  406                                                 break;
  407                                         tdksignal(ttd, uap->sig, &ksi);
  408                                 }
  409                         }
  410                         PROC_UNLOCK(p);
  411                 }
  412         } else {
  413                 error = 0;
  414                 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  415                 if (ttd == NULL)
  416                         return (ESRCH);
  417                 if (uap->sig == 0)
  418                         ;
  419                 else if (!_SIG_VALID(uap->sig))
  420                         error = EINVAL;
  421                 else 
  422                         tdksignal(ttd, uap->sig, &ksi);
  423                 PROC_UNLOCK(ttd->td_proc);
  424         }
  425         return (error);
  426 }
  427 
  428 int
  429 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
  430     /* pid_t pid, long id, int sig */
  431 {
  432         ksiginfo_t ksi;
  433         struct thread *ttd;
  434         struct proc *p;
  435         int error;
  436 
  437         AUDIT_ARG_SIGNUM(uap->sig);
  438 
  439         ksiginfo_init(&ksi);
  440         ksi.ksi_signo = uap->sig;
  441         ksi.ksi_code = SI_LWP;
  442         ksi.ksi_pid = td->td_proc->p_pid;
  443         ksi.ksi_uid = td->td_ucred->cr_ruid;
  444         if (uap->id == -1) {
  445                 if ((p = pfind(uap->pid)) == NULL)
  446                         return (ESRCH);
  447                 AUDIT_ARG_PROCESS(p);
  448                 error = p_cansignal(td, p, uap->sig);
  449                 if (error) {
  450                         PROC_UNLOCK(p);
  451                         return (error);
  452                 }
  453                 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
  454                         error = EINVAL;
  455                 } else {
  456                         error = ESRCH;
  457                         FOREACH_THREAD_IN_PROC(p, ttd) {
  458                                 if (ttd != td) {
  459                                         error = 0;
  460                                         if (uap->sig == 0)
  461                                                 break;
  462                                         tdksignal(ttd, uap->sig, &ksi);
  463                                 }
  464                         }
  465                 }
  466                 PROC_UNLOCK(p);
  467         } else {
  468                 ttd = tdfind((lwpid_t)uap->id, uap->pid);
  469                 if (ttd == NULL)
  470                         return (ESRCH);
  471                 p = ttd->td_proc;
  472                 AUDIT_ARG_PROCESS(p);
  473                 error = p_cansignal(td, p, uap->sig);
  474                 if (uap->sig == 0)
  475                         ;
  476                 else if (!_SIG_VALID(uap->sig))
  477                         error = EINVAL;
  478                 else
  479                         tdksignal(ttd, uap->sig, &ksi);
  480                 PROC_UNLOCK(p);
  481         }
  482         return (error);
  483 }
  484 
  485 int
  486 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
  487         /* const struct timespec *timeout */
  488 {
  489         struct timespec ts, *tsp;
  490         int error;
  491 
  492         tsp = NULL;
  493         if (uap->timeout != NULL) {
  494                 error = umtx_copyin_timeout(uap->timeout, &ts);
  495                 if (error != 0)
  496                         return (error);
  497                 tsp = &ts;
  498         }
  499 
  500         return (kern_thr_suspend(td, tsp));
  501 }
  502 
  503 int
  504 kern_thr_suspend(struct thread *td, struct timespec *tsp)
  505 {
  506         struct proc *p = td->td_proc;
  507         struct timeval tv;
  508         int error = 0;
  509         int timo = 0;
  510 
  511         if (td->td_pflags & TDP_WAKEUP) {
  512                 td->td_pflags &= ~TDP_WAKEUP;
  513                 return (0);
  514         }
  515 
  516         if (tsp != NULL) {
  517                 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
  518                         error = EWOULDBLOCK;
  519                 else {
  520                         TIMESPEC_TO_TIMEVAL(&tv, tsp);
  521                         timo = tvtohz(&tv);
  522                 }
  523         }
  524 
  525         PROC_LOCK(p);
  526         if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
  527                 error = msleep((void *)td, &p->p_mtx,
  528                          PCATCH, "lthr", timo);
  529 
  530         if (td->td_flags & TDF_THRWAKEUP) {
  531                 thread_lock(td);
  532                 td->td_flags &= ~TDF_THRWAKEUP;
  533                 thread_unlock(td);
  534                 PROC_UNLOCK(p);
  535                 return (0);
  536         }
  537         PROC_UNLOCK(p);
  538         if (error == EWOULDBLOCK)
  539                 error = ETIMEDOUT;
  540         else if (error == ERESTART) {
  541                 if (timo != 0)
  542                         error = EINTR;
  543         }
  544         return (error);
  545 }
  546 
  547 int
  548 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
  549         /* long id */
  550 {
  551         struct proc *p;
  552         struct thread *ttd;
  553 
  554         if (uap->id == td->td_tid) {
  555                 td->td_pflags |= TDP_WAKEUP;
  556                 return (0);
  557         } 
  558 
  559         p = td->td_proc;
  560         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  561         if (ttd == NULL)
  562                 return (ESRCH);
  563         thread_lock(ttd);
  564         ttd->td_flags |= TDF_THRWAKEUP;
  565         thread_unlock(ttd);
  566         wakeup((void *)ttd);
  567         PROC_UNLOCK(p);
  568         return (0);
  569 }
  570 
  571 int
  572 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
  573 {
  574         struct proc *p;
  575         char name[MAXCOMLEN + 1];
  576         struct thread *ttd;
  577         int error;
  578 
  579         error = 0;
  580         name[0] = '\0';
  581         if (uap->name != NULL) {
  582                 error = copyinstr(uap->name, name, sizeof(name), NULL);
  583                 if (error == ENAMETOOLONG) {
  584                         error = copyin(uap->name, name, sizeof(name) - 1);
  585                         name[sizeof(name) - 1] = '\0';
  586                 }
  587                 if (error)
  588                         return (error);
  589         }
  590         p = td->td_proc;
  591         ttd = tdfind((lwpid_t)uap->id, p->p_pid);
  592         if (ttd == NULL)
  593                 return (ESRCH);
  594         strcpy(ttd->td_name, name);
  595 #ifdef KTR
  596         sched_clear_tdname(ttd);
  597 #endif
  598         PROC_UNLOCK(p);
  599         return (error);
  600 }
  601 
  602 int
  603 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
  604 {
  605 
  606         /* Have race condition but it is cheap. */
  607         if (p->p_numthreads >= max_threads_per_proc) {
  608                 ++max_threads_hits;
  609                 return (EPROCLIM);
  610         }
  611 
  612         *ntd = thread_alloc(pages);
  613         if (*ntd == NULL)
  614                 return (ENOMEM);
  615 
  616         return (0);
  617 }
Cache object: 246637d46d8e2587acbb3ccc747b86bc
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_thr.c

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