linux_fork.c

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    1 /*-
    2  * Copyright (c) 2004 Tim J. Robbins
    3  * Copyright (c) 2002 Doug Rabson
    4  * Copyright (c) 2000 Marcel Moolenaar
    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, this list of conditions and the following disclaimer
   12  *    in this position and unchanged.
   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/10.4/sys/compat/linux/linux_fork.c 299705 2016-05-14 00:35:49Z pfg $");
   31 
   32 #include "opt_compat.h"
   33 #include "opt_kdtrace.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/imgact.h>
   38 #include <sys/ktr.h>
   39 #include <sys/lock.h>
   40 #include <sys/mutex.h>
   41 #include <sys/proc.h>
   42 #include <sys/racct.h>
   43 #include <sys/sched.h>
   44 #include <sys/syscallsubr.h>
   45 #include <sys/sx.h>
   46 #include <sys/unistd.h>
   47 #include <sys/wait.h>
   48 
   49 #include <vm/vm.h>
   50 #include <vm/pmap.h>
   51 #include <vm/vm_map.h>
   52 
   53 #ifdef COMPAT_LINUX32
   54 #include <machine/../linux32/linux.h>
   55 #include <machine/../linux32/linux32_proto.h>
   56 #else
   57 #include <machine/../linux/linux.h>
   58 #include <machine/../linux/linux_proto.h>
   59 #endif
   60 #include <compat/linux/linux_emul.h>
   61 #include <compat/linux/linux_futex.h>
   62 #include <compat/linux/linux_misc.h>
   63 #include <compat/linux/linux_util.h>
   64 
   65 int
   66 linux_fork(struct thread *td, struct linux_fork_args *args)
   67 {
   68         int error;
   69         struct proc *p2;
   70         struct thread *td2;
   71 
   72 #ifdef DEBUG
   73         if (ldebug(fork))
   74                 printf(ARGS(fork, ""));
   75 #endif
   76 
   77         if ((error = fork1(td, RFFDG | RFPROC | RFSTOPPED, 0, &p2, NULL, 0))
   78             != 0)
   79                 return (error);
   80 
   81         td2 = FIRST_THREAD_IN_PROC(p2);
   82 
   83         linux_proc_init(td, td2, 0);
   84 
   85         td->td_retval[0] = p2->p_pid;
   86 
   87         /*
   88          * Make this runnable after we are finished with it.
   89          */
   90         thread_lock(td2);
   91         TD_SET_CAN_RUN(td2);
   92         sched_add(td2, SRQ_BORING);
   93         thread_unlock(td2);
   94 
   95         return (0);
   96 }
   97 
   98 int
   99 linux_vfork(struct thread *td, struct linux_vfork_args *args)
  100 {
  101         int error;
  102         struct proc *p2;
  103         struct thread *td2;
  104 
  105 #ifdef DEBUG
  106         if (ldebug(vfork))
  107                 printf(ARGS(vfork, ""));
  108 #endif
  109 
  110         if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED,
  111             0, &p2, NULL, 0)) != 0)
  112                 return (error);
  113 
  114         td2 = FIRST_THREAD_IN_PROC(p2);
  115 
  116         linux_proc_init(td, td2, 0);
  117 
  118         td->td_retval[0] = p2->p_pid;
  119 
  120         /*
  121          * Make this runnable after we are finished with it.
  122          */
  123         thread_lock(td2);
  124         TD_SET_CAN_RUN(td2);
  125         sched_add(td2, SRQ_BORING);
  126         thread_unlock(td2);
  127 
  128         return (0);
  129 }
  130 
  131 static int
  132 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
  133 {
  134         int error, ff = RFPROC | RFSTOPPED;
  135         struct proc *p2;
  136         struct thread *td2;
  137         int exit_signal;
  138         struct linux_emuldata *em;
  139 
  140 #ifdef DEBUG
  141         if (ldebug(clone)) {
  142                 printf(ARGS(clone, "flags %x, stack %p, parent tid: %p, "
  143                     "child tid: %p"), (unsigned)args->flags,
  144                     args->stack, args->parent_tidptr, args->child_tidptr);
  145         }
  146 #endif
  147 
  148         exit_signal = args->flags & 0x000000ff;
  149         if (LINUX_SIG_VALID(exit_signal)) {
  150                 exit_signal = linux_to_bsd_signal(exit_signal);
  151         } else if (exit_signal != 0)
  152                 return (EINVAL);
  153 
  154         if (args->flags & LINUX_CLONE_VM)
  155                 ff |= RFMEM;
  156         if (args->flags & LINUX_CLONE_SIGHAND)
  157                 ff |= RFSIGSHARE;
  158         /*
  159          * XXX: In Linux, sharing of fs info (chroot/cwd/umask)
  160          * and open files is independent.  In FreeBSD, its in one
  161          * structure but in reality it does not cause any problems
  162          * because both of these flags are usually set together.
  163          */
  164         if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS)))
  165                 ff |= RFFDG;
  166 
  167         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  168                 if (args->parent_tidptr == NULL)
  169                         return (EINVAL);
  170 
  171         if (args->flags & LINUX_CLONE_VFORK)
  172                 ff |= RFPPWAIT;
  173 
  174         error = fork1(td, ff, 0, &p2, NULL, 0);
  175         if (error)
  176                 return (error);
  177 
  178         td2 = FIRST_THREAD_IN_PROC(p2);
  179 
  180         /* create the emuldata */
  181         linux_proc_init(td, td2, args->flags);
  182 
  183         em = em_find(td2);
  184         KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
  185 
  186         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  187                 em->child_set_tid = args->child_tidptr;
  188         else
  189                 em->child_set_tid = NULL;
  190 
  191         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  192                 em->child_clear_tid = args->child_tidptr;
  193         else
  194                 em->child_clear_tid = NULL;
  195 
  196         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  197                 error = copyout(&p2->p_pid, args->parent_tidptr,
  198                     sizeof(p2->p_pid));
  199                 if (error)
  200                         printf(LMSG("copyout failed!"));
  201         }
  202 
  203         PROC_LOCK(p2);
  204         p2->p_sigparent = exit_signal;
  205         PROC_UNLOCK(p2);
  206         /*
  207          * In a case of stack = NULL, we are supposed to COW calling process
  208          * stack. This is what normal fork() does, so we just keep tf_rsp arg
  209          * intact.
  210          */
  211         linux_set_upcall_kse(td2, PTROUT(args->stack));
  212 
  213         if (args->flags & LINUX_CLONE_SETTLS)
  214                 linux_set_cloned_tls(td2, args->tls);
  215 
  216         /*
  217          * If CLONE_PARENT is set, then the parent of the new process will be 
  218          * the same as that of the calling process.
  219          */
  220         if (args->flags & LINUX_CLONE_PARENT) {
  221                 sx_xlock(&proctree_lock);
  222                 PROC_LOCK(p2);
  223                 proc_reparent(p2, td->td_proc->p_pptr);
  224                 PROC_UNLOCK(p2);
  225                 sx_xunlock(&proctree_lock);
  226         }
  227 
  228 #ifdef DEBUG
  229         if (ldebug(clone))
  230                 printf(LMSG("clone: successful rfork to %d, "
  231                     "stack %p sig = %d"), (int)p2->p_pid, args->stack,
  232                     exit_signal);
  233 #endif
  234 
  235         /*
  236          * Make this runnable after we are finished with it.
  237          */
  238         thread_lock(td2);
  239         TD_SET_CAN_RUN(td2);
  240         sched_add(td2, SRQ_BORING);
  241         thread_unlock(td2);
  242 
  243         td->td_retval[0] = p2->p_pid;
  244 
  245         return (0);
  246 }
  247 
  248 static int
  249 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
  250 {
  251         struct linux_emuldata *em;
  252         struct thread *newtd;
  253         struct proc *p;
  254         int error;
  255 
  256 #ifdef DEBUG
  257         if (ldebug(clone)) {
  258                 printf(ARGS(clone, "thread: flags %x, stack %p, parent tid: %p, "
  259                     "child tid: %p"), (unsigned)args->flags,
  260                     args->stack, args->parent_tidptr, args->child_tidptr);
  261         }
  262 #endif
  263 
  264         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  265             td->td_tid, (unsigned)args->flags,
  266             args->parent_tidptr, args->child_tidptr);
  267 
  268         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  269                 if (args->parent_tidptr == NULL)
  270                         return (EINVAL);
  271 
  272         /* Threads should be created with own stack */
  273         if (args->stack == NULL)
  274                 return (EINVAL);
  275 
  276         p = td->td_proc;
  277 
  278 #ifdef RACCT
  279         if (racct_enable) {
  280                 PROC_LOCK(p);
  281                 error = racct_add(p, RACCT_NTHR, 1);
  282                 PROC_UNLOCK(p);
  283                 if (error != 0)
  284                         return (EPROCLIM);
  285         }
  286 #endif
  287 
  288         /* Initialize our td */
  289         error = kern_thr_alloc(p, 0, &newtd);
  290         if (error)
  291                 goto fail;
  292                                                                                                                 
  293         cpu_set_upcall(newtd, td);
  294 
  295         bzero(&newtd->td_startzero,
  296             __rangeof(struct thread, td_startzero, td_endzero));
  297         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  298             __rangeof(struct thread, td_startcopy, td_endcopy));
  299 
  300         newtd->td_proc = p;
  301         newtd->td_ucred = crhold(td->td_ucred);
  302 
  303         /* create the emuldata */
  304         linux_proc_init(td, newtd, args->flags);
  305 
  306         em = em_find(newtd);
  307         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  308 
  309         if (args->flags & LINUX_CLONE_SETTLS)
  310                 linux_set_cloned_tls(newtd, args->tls);
  311 
  312         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  313                 em->child_set_tid = args->child_tidptr;
  314         else
  315                 em->child_set_tid = NULL;
  316 
  317         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  318                 em->child_clear_tid = args->child_tidptr;
  319         else
  320                 em->child_clear_tid = NULL;
  321 
  322         cpu_thread_clean(newtd);
  323         
  324         linux_set_upcall_kse(newtd, PTROUT(args->stack));
  325 
  326         PROC_LOCK(p);
  327         p->p_flag |= P_HADTHREADS;
  328         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  329 
  330         if (args->flags & LINUX_CLONE_PARENT)
  331                 thread_link(newtd, p->p_pptr);
  332         else
  333                 thread_link(newtd, p);
  334 
  335         thread_lock(td);
  336         /* let the scheduler know about these things. */
  337         sched_fork_thread(td, newtd);
  338         thread_unlock(td);
  339         if (P_SHOULDSTOP(p))
  340                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  341         PROC_UNLOCK(p);
  342 
  343         tidhash_add(newtd);
  344 
  345 #ifdef DEBUG
  346         if (ldebug(clone))
  347                 printf(ARGS(clone, "successful clone to %d, stack %p"),
  348                 (int)newtd->td_tid, args->stack);
  349 #endif
  350 
  351         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  352             td->td_tid, newtd->td_tid);
  353 
  354         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  355                 error = copyout(&newtd->td_tid, args->parent_tidptr,
  356                     sizeof(newtd->td_tid));
  357                 if (error)
  358                         printf(LMSG("clone_thread: copyout failed!"));
  359         }
  360 
  361         /*
  362          * Make this runnable after we are finished with it.
  363          */
  364         thread_lock(newtd);
  365         TD_SET_CAN_RUN(newtd);
  366         sched_add(newtd, SRQ_BORING);
  367         thread_unlock(newtd);
  368 
  369         td->td_retval[0] = newtd->td_tid;
  370 
  371         return (0);
  372 
  373 fail:
  374 #ifdef RACCT
  375         if (racct_enable) {
  376                 PROC_LOCK(p);
  377                 racct_sub(p, RACCT_NTHR, 1);
  378                 PROC_UNLOCK(p);
  379         }
  380 #endif
  381         return (error);
  382 }
  383 
  384 int
  385 linux_clone(struct thread *td, struct linux_clone_args *args)
  386 {
  387 
  388         if (args->flags & LINUX_CLONE_THREAD)
  389                 return (linux_clone_thread(td, args));
  390         else
  391                 return (linux_clone_proc(td, args));
  392 }
  393 
  394 int
  395 linux_exit(struct thread *td, struct linux_exit_args *args)
  396 {
  397         struct linux_emuldata *em;
  398 
  399         em = em_find(td);
  400         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  401 
  402         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  403 
  404         linux_thread_detach(td);
  405 
  406         /*
  407          * XXX. When the last two threads of a process
  408          * exit via pthread_exit() try thr_exit() first.
  409          */
  410         kern_thr_exit(td);
  411         exit1(td, W_EXITCODE(args->rval, 0));
  412                 /* NOTREACHED */
  413 }
  414 
  415 int
  416 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  417 {
  418         struct linux_emuldata *em;
  419 
  420         em = em_find(td);
  421         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  422 
  423         em->child_clear_tid = args->tidptr;
  424 
  425         td->td_retval[0] = em->em_tid;
  426 
  427         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  428             em->em_tid, args->tidptr, td->td_retval[0]);
  429 
  430         return (0);
  431 }
  432 
  433 void
  434 linux_thread_detach(struct thread *td)
  435 {
  436         struct linux_sys_futex_args cup;
  437         struct linux_emuldata *em;
  438         int *child_clear_tid;
  439         int error;
  440 
  441         em = em_find(td);
  442         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  443 
  444         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  445 
  446         release_futexes(td, em);
  447 
  448         child_clear_tid = em->child_clear_tid;
  449 
  450         if (child_clear_tid != NULL) {
  451 
  452                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  453                     em->em_tid, child_clear_tid);
  454         
  455                 error = suword32(child_clear_tid, 0);
  456                 if (error != 0)
  457                         return;
  458 
  459                 cup.uaddr = child_clear_tid;
  460                 cup.op = LINUX_FUTEX_WAKE;
  461                 cup.val = 1;            /* wake one */
  462                 cup.timeout = NULL;
  463                 cup.uaddr2 = NULL;
  464                 cup.val3 = 0;
  465                 error = linux_sys_futex(td, &cup);
  466                 /*
  467                  * this cannot happen at the moment and if this happens it
  468                  * probably means there is a user space bug
  469                  */
  470                 if (error != 0)
  471                         linux_msg(td, "futex stuff in thread_detach failed.");
  472         }
  473 }
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FreeBSD/Linux Kernel Cross Reference sys/compat/linux/linux_fork.c

FreeBSD/Linux Kernel Cross Reference
sys/compat/linux/linux_fork.c
