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/10.3/sys/compat/linux/linux_fork.c 293608 2016-01-09 18:28:15Z dchagin $");
   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 independant.  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 #ifdef DEBUG
  217         if (ldebug(clone))
  218                 printf(LMSG("clone: successful rfork to %d, "
  219                     "stack %p sig = %d"), (int)p2->p_pid, args->stack,
  220                     exit_signal);
  221 #endif
  222 
  223         /*
  224          * Make this runnable after we are finished with it.
  225          */
  226         thread_lock(td2);
  227         TD_SET_CAN_RUN(td2);
  228         sched_add(td2, SRQ_BORING);
  229         thread_unlock(td2);
  230 
  231         td->td_retval[0] = p2->p_pid;
  232 
  233         return (0);
  234 }
  235 
  236 static int
  237 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
  238 {
  239         struct linux_emuldata *em;
  240         struct thread *newtd;
  241         struct proc *p;
  242         int error;
  243 
  244 #ifdef DEBUG
  245         if (ldebug(clone)) {
  246                 printf(ARGS(clone, "thread: flags %x, stack %p, parent tid: %p, "
  247                     "child tid: %p"), (unsigned)args->flags,
  248                     args->stack, args->parent_tidptr, args->child_tidptr);
  249         }
  250 #endif
  251 
  252         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  253             td->td_tid, (unsigned)args->flags,
  254             args->parent_tidptr, args->child_tidptr);
  255 
  256         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  257                 if (args->parent_tidptr == NULL)
  258                         return (EINVAL);
  259 
  260         /* Threads should be created with own stack */
  261         if (args->stack == NULL)
  262                 return (EINVAL);
  263 
  264         p = td->td_proc;
  265 
  266 #ifdef RACCT
  267         if (racct_enable) {
  268                 PROC_LOCK(p);
  269                 error = racct_add(p, RACCT_NTHR, 1);
  270                 PROC_UNLOCK(p);
  271                 if (error != 0)
  272                         return (EPROCLIM);
  273         }
  274 #endif
  275 
  276         /* Initialize our td */
  277         error = kern_thr_alloc(p, 0, &newtd);
  278         if (error)
  279                 goto fail;
  280                                                                                                                 
  281         cpu_set_upcall(newtd, td);
  282 
  283         bzero(&newtd->td_startzero,
  284             __rangeof(struct thread, td_startzero, td_endzero));
  285         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  286             __rangeof(struct thread, td_startcopy, td_endcopy));
  287 
  288         newtd->td_proc = p;
  289         newtd->td_ucred = crhold(td->td_ucred);
  290 
  291         /* create the emuldata */
  292         linux_proc_init(td, newtd, args->flags);
  293 
  294         em = em_find(newtd);
  295         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  296 
  297         if (args->flags & LINUX_CLONE_SETTLS)
  298                 linux_set_cloned_tls(newtd, args->tls);
  299 
  300         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  301                 em->child_set_tid = args->child_tidptr;
  302         else
  303                 em->child_set_tid = NULL;
  304 
  305         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  306                 em->child_clear_tid = args->child_tidptr;
  307         else
  308                 em->child_clear_tid = NULL;
  309 
  310         cpu_thread_clean(newtd);
  311         
  312         linux_set_upcall_kse(newtd, PTROUT(args->stack));
  313 
  314         PROC_LOCK(p);
  315         p->p_flag |= P_HADTHREADS;
  316         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  317 
  318         if (args->flags & LINUX_CLONE_PARENT)
  319                 thread_link(newtd, p->p_pptr);
  320         else
  321                 thread_link(newtd, p);
  322 
  323         thread_lock(td);
  324         /* let the scheduler know about these things. */
  325         sched_fork_thread(td, newtd);
  326         thread_unlock(td);
  327         if (P_SHOULDSTOP(p))
  328                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  329         PROC_UNLOCK(p);
  330 
  331         tidhash_add(newtd);
  332 
  333 #ifdef DEBUG
  334         if (ldebug(clone))
  335                 printf(ARGS(clone, "successful clone to %d, stack %p"),
  336                 (int)newtd->td_tid, args->stack);
  337 #endif
  338 
  339         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  340             td->td_tid, newtd->td_tid);
  341 
  342         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  343                 error = copyout(&newtd->td_tid, args->parent_tidptr,
  344                     sizeof(newtd->td_tid));
  345                 if (error)
  346                         printf(LMSG("clone_thread: copyout failed!"));
  347         }
  348 
  349         /*
  350          * Make this runnable after we are finished with it.
  351          */
  352         thread_lock(newtd);
  353         TD_SET_CAN_RUN(newtd);
  354         sched_add(newtd, SRQ_BORING);
  355         thread_unlock(newtd);
  356 
  357         td->td_retval[0] = newtd->td_tid;
  358 
  359         return (0);
  360 
  361 fail:
  362 #ifdef RACCT
  363         if (racct_enable) {
  364                 PROC_LOCK(p);
  365                 racct_sub(p, RACCT_NTHR, 1);
  366                 PROC_UNLOCK(p);
  367         }
  368 #endif
  369         return (error);
  370 }
  371 
  372 int
  373 linux_clone(struct thread *td, struct linux_clone_args *args)
  374 {
  375 
  376         if (args->flags & LINUX_CLONE_THREAD)
  377                 return (linux_clone_thread(td, args));
  378         else
  379                 return (linux_clone_proc(td, args));
  380 }
  381 
  382 int
  383 linux_exit(struct thread *td, struct linux_exit_args *args)
  384 {
  385         struct linux_emuldata *em;
  386 
  387         em = em_find(td);
  388         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  389 
  390         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  391 
  392         linux_thread_detach(td);
  393 
  394         /*
  395          * XXX. When the last two threads of a process
  396          * exit via pthread_exit() try thr_exit() first.
  397          */
  398         kern_thr_exit(td);
  399         exit1(td, W_EXITCODE(args->rval, 0));
  400                 /* NOTREACHED */
  401 }
  402 
  403 int
  404 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  405 {
  406         struct linux_emuldata *em;
  407 
  408         em = em_find(td);
  409         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  410 
  411         em->child_clear_tid = args->tidptr;
  412 
  413         td->td_retval[0] = em->em_tid;
  414 
  415         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  416             em->em_tid, args->tidptr, td->td_retval[0]);
  417 
  418         return (0);
  419 }
  420 
  421 void
  422 linux_thread_detach(struct thread *td)
  423 {
  424         struct linux_sys_futex_args cup;
  425         struct linux_emuldata *em;
  426         int *child_clear_tid;
  427         int error;
  428 
  429         em = em_find(td);
  430         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  431 
  432         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  433 
  434         release_futexes(td, em);
  435 
  436         child_clear_tid = em->child_clear_tid;
  437 
  438         if (child_clear_tid != NULL) {
  439 
  440                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  441                     em->em_tid, child_clear_tid);
  442         
  443                 error = suword32(child_clear_tid, 0);
  444                 if (error != 0)
  445                         return;
  446 
  447                 cup.uaddr = child_clear_tid;
  448                 cup.op = LINUX_FUTEX_WAKE;
  449                 cup.val = 1;            /* wake one */
  450                 cup.timeout = NULL;
  451                 cup.uaddr2 = NULL;
  452                 cup.val3 = 0;
  453                 error = linux_sys_futex(td, &cup);
  454                 /*
  455                  * this cannot happen at the moment and if this happens it
  456                  * probably means there is a user space bug
  457                  */
  458                 if (error != 0)
  459                         linux_msg(td, "futex stuff in thread_detach failed.");
  460         }
  461 }
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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
