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("$FreeBSD$");
   31 
   32 #include "opt_compat.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/imgact.h>
   37 #include <sys/ktr.h>
   38 #include <sys/lock.h>
   39 #include <sys/mutex.h>
   40 #include <sys/proc.h>
   41 #include <sys/ptrace.h>
   42 #include <sys/racct.h>
   43 #include <sys/sched.h>
   44 #include <sys/syscallsubr.h>
   45 #include <sys/sx.h>
   46 #include <sys/umtx.h>
   47 #include <sys/unistd.h>
   48 #include <sys/wait.h>
   49 
   50 #include <vm/vm.h>
   51 #include <vm/pmap.h>
   52 #include <vm/vm_map.h>
   53 
   54 #ifdef COMPAT_LINUX32
   55 #include <machine/../linux32/linux.h>
   56 #include <machine/../linux32/linux32_proto.h>
   57 #else
   58 #include <machine/../linux/linux.h>
   59 #include <machine/../linux/linux_proto.h>
   60 #endif
   61 #include <compat/linux/linux_emul.h>
   62 #include <compat/linux/linux_futex.h>
   63 #include <compat/linux/linux_misc.h>
   64 #include <compat/linux/linux_util.h>
   65 
   66 #ifdef LINUX_LEGACY_SYSCALLS
   67 int
   68 linux_fork(struct thread *td, struct linux_fork_args *args)
   69 {
   70         struct fork_req fr;
   71         int error;
   72         struct proc *p2;
   73         struct thread *td2;
   74 
   75 #ifdef DEBUG
   76         if (ldebug(fork))
   77                 printf(ARGS(fork, ""));
   78 #endif
   79 
   80         bzero(&fr, sizeof(fr));
   81         fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
   82         fr.fr_procp = &p2;
   83         if ((error = fork1(td, &fr)) != 0)
   84                 return (error);
   85 
   86         td2 = FIRST_THREAD_IN_PROC(p2);
   87 
   88         linux_proc_init(td, td2, 0);
   89 
   90         td->td_retval[0] = p2->p_pid;
   91 
   92         /*
   93          * Make this runnable after we are finished with it.
   94          */
   95         thread_lock(td2);
   96         TD_SET_CAN_RUN(td2);
   97         sched_add(td2, SRQ_BORING);
   98         thread_unlock(td2);
   99 
  100         return (0);
  101 }
  102 
  103 int
  104 linux_vfork(struct thread *td, struct linux_vfork_args *args)
  105 {
  106         struct fork_req fr;
  107         int error;
  108         struct proc *p2;
  109         struct thread *td2;
  110 
  111 #ifdef DEBUG
  112         if (ldebug(vfork))
  113                 printf(ARGS(vfork, ""));
  114 #endif
  115 
  116         bzero(&fr, sizeof(fr));
  117         fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
  118         fr.fr_procp = &p2;
  119         if ((error = fork1(td, &fr)) != 0)
  120                 return (error);
  121 
  122         td2 = FIRST_THREAD_IN_PROC(p2);
  123 
  124         linux_proc_init(td, td2, 0);
  125 
  126         td->td_retval[0] = p2->p_pid;
  127 
  128         /*
  129          * Make this runnable after we are finished with it.
  130          */
  131         thread_lock(td2);
  132         TD_SET_CAN_RUN(td2);
  133         sched_add(td2, SRQ_BORING);
  134         thread_unlock(td2);
  135 
  136         return (0);
  137 }
  138 #endif
  139 
  140 static int
  141 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
  142 {
  143         struct fork_req fr;
  144         int error, ff = RFPROC | RFSTOPPED;
  145         struct proc *p2;
  146         struct thread *td2;
  147         int exit_signal;
  148         struct linux_emuldata *em;
  149 
  150 #ifdef DEBUG
  151         if (ldebug(clone)) {
  152                 printf(ARGS(clone, "flags %x, stack %p, parent tid: %p, "
  153                     "child tid: %p"), (unsigned)args->flags,
  154                     args->stack, args->parent_tidptr, args->child_tidptr);
  155         }
  156 #endif
  157 
  158         exit_signal = args->flags & 0x000000ff;
  159         if (LINUX_SIG_VALID(exit_signal)) {
  160                 exit_signal = linux_to_bsd_signal(exit_signal);
  161         } else if (exit_signal != 0)
  162                 return (EINVAL);
  163 
  164         if (args->flags & LINUX_CLONE_VM)
  165                 ff |= RFMEM;
  166         if (args->flags & LINUX_CLONE_SIGHAND)
  167                 ff |= RFSIGSHARE;
  168         /*
  169          * XXX: In Linux, sharing of fs info (chroot/cwd/umask)
  170          * and open files is independent.  In FreeBSD, its in one
  171          * structure but in reality it does not cause any problems
  172          * because both of these flags are usually set together.
  173          */
  174         if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS)))
  175                 ff |= RFFDG;
  176 
  177         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  178                 if (args->parent_tidptr == NULL)
  179                         return (EINVAL);
  180 
  181         if (args->flags & LINUX_CLONE_VFORK)
  182                 ff |= RFPPWAIT;
  183 
  184         bzero(&fr, sizeof(fr));
  185         fr.fr_flags = ff;
  186         fr.fr_procp = &p2;
  187         error = fork1(td, &fr);
  188         if (error)
  189                 return (error);
  190 
  191         td2 = FIRST_THREAD_IN_PROC(p2);
  192 
  193         /* create the emuldata */
  194         linux_proc_init(td, td2, args->flags);
  195 
  196         em = em_find(td2);
  197         KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
  198 
  199         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  200                 em->child_set_tid = args->child_tidptr;
  201         else
  202                 em->child_set_tid = NULL;
  203 
  204         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  205                 em->child_clear_tid = args->child_tidptr;
  206         else
  207                 em->child_clear_tid = NULL;
  208 
  209         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  210                 error = copyout(&p2->p_pid, args->parent_tidptr,
  211                     sizeof(p2->p_pid));
  212                 if (error)
  213                         printf(LMSG("copyout failed!"));
  214         }
  215 
  216         PROC_LOCK(p2);
  217         p2->p_sigparent = exit_signal;
  218         PROC_UNLOCK(p2);
  219         /*
  220          * In a case of stack = NULL, we are supposed to COW calling process
  221          * stack. This is what normal fork() does, so we just keep tf_rsp arg
  222          * intact.
  223          */
  224         linux_set_upcall_kse(td2, PTROUT(args->stack));
  225 
  226         if (args->flags & LINUX_CLONE_SETTLS)
  227                 linux_set_cloned_tls(td2, args->tls);
  228 
  229         /*
  230          * If CLONE_PARENT is set, then the parent of the new process will be
  231          * the same as that of the calling process.
  232          */
  233         if (args->flags & LINUX_CLONE_PARENT) {
  234                 sx_xlock(&proctree_lock);
  235                 PROC_LOCK(p2);
  236                 proc_reparent(p2, td->td_proc->p_pptr);
  237                 PROC_UNLOCK(p2);
  238                 sx_xunlock(&proctree_lock);
  239         }
  240 
  241 #ifdef DEBUG
  242         if (ldebug(clone))
  243                 printf(LMSG("clone: successful rfork to %d, "
  244                     "stack %p sig = %d"), (int)p2->p_pid, args->stack,
  245                     exit_signal);
  246 #endif
  247 
  248         /*
  249          * Make this runnable after we are finished with it.
  250          */
  251         thread_lock(td2);
  252         TD_SET_CAN_RUN(td2);
  253         sched_add(td2, SRQ_BORING);
  254         thread_unlock(td2);
  255 
  256         td->td_retval[0] = p2->p_pid;
  257 
  258         return (0);
  259 }
  260 
  261 static int
  262 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
  263 {
  264         struct linux_emuldata *em;
  265         struct thread *newtd;
  266         struct proc *p;
  267         int error;
  268 
  269 #ifdef DEBUG
  270         if (ldebug(clone)) {
  271                 printf(ARGS(clone, "thread: flags %x, stack %p, parent tid: %p, "
  272                     "child tid: %p"), (unsigned)args->flags,
  273                     args->stack, args->parent_tidptr, args->child_tidptr);
  274         }
  275 #endif
  276 
  277         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  278             td->td_tid, (unsigned)args->flags,
  279             args->parent_tidptr, args->child_tidptr);
  280 
  281         if ((args->flags & LINUX_CLONE_PARENT) != 0)
  282                 return (EINVAL);
  283         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  284                 if (args->parent_tidptr == NULL)
  285                         return (EINVAL);
  286 
  287         /* Threads should be created with own stack */
  288         if (args->stack == NULL)
  289                 return (EINVAL);
  290 
  291         p = td->td_proc;
  292 
  293 #ifdef RACCT
  294         if (racct_enable) {
  295                 PROC_LOCK(p);
  296                 error = racct_add(p, RACCT_NTHR, 1);
  297                 PROC_UNLOCK(p);
  298                 if (error != 0)
  299                         return (EPROCLIM);
  300         }
  301 #endif
  302 
  303         /* Initialize our td */
  304         error = kern_thr_alloc(p, 0, &newtd);
  305         if (error)
  306                 goto fail;
  307 
  308         cpu_copy_thread(newtd, td);
  309 
  310         bzero(&newtd->td_startzero,
  311             __rangeof(struct thread, td_startzero, td_endzero));
  312         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  313             __rangeof(struct thread, td_startcopy, td_endcopy));
  314         newtd->td_sa = td->td_sa;
  315 
  316         newtd->td_proc = p;
  317         thread_cow_get(newtd, td);
  318 
  319         /* create the emuldata */
  320         linux_proc_init(td, newtd, args->flags);
  321 
  322         em = em_find(newtd);
  323         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  324 
  325         if (args->flags & LINUX_CLONE_SETTLS)
  326                 linux_set_cloned_tls(newtd, args->tls);
  327 
  328         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  329                 em->child_set_tid = args->child_tidptr;
  330         else
  331                 em->child_set_tid = NULL;
  332 
  333         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  334                 em->child_clear_tid = args->child_tidptr;
  335         else
  336                 em->child_clear_tid = NULL;
  337 
  338         cpu_thread_clean(newtd);
  339 
  340         linux_set_upcall_kse(newtd, PTROUT(args->stack));
  341 
  342         PROC_LOCK(p);
  343         p->p_flag |= P_HADTHREADS;
  344         thread_link(newtd, p);
  345         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  346 
  347         thread_lock(td);
  348         /* let the scheduler know about these things. */
  349         sched_fork_thread(td, newtd);
  350         thread_unlock(td);
  351         if (P_SHOULDSTOP(p))
  352                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  353 
  354         if (p->p_ptevents & PTRACE_LWP)
  355                 newtd->td_dbgflags |= TDB_BORN;
  356         PROC_UNLOCK(p);
  357 
  358         tidhash_add(newtd);
  359 
  360 #ifdef DEBUG
  361         if (ldebug(clone))
  362                 printf(ARGS(clone, "successful clone to %d, stack %p"),
  363                 (int)newtd->td_tid, args->stack);
  364 #endif
  365 
  366         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  367             td->td_tid, newtd->td_tid);
  368 
  369         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  370                 error = copyout(&newtd->td_tid, args->parent_tidptr,
  371                     sizeof(newtd->td_tid));
  372                 if (error)
  373                         printf(LMSG("clone_thread: copyout failed!"));
  374         }
  375 
  376         /*
  377          * Make this runnable after we are finished with it.
  378          */
  379         thread_lock(newtd);
  380         TD_SET_CAN_RUN(newtd);
  381         sched_add(newtd, SRQ_BORING);
  382         thread_unlock(newtd);
  383 
  384         td->td_retval[0] = newtd->td_tid;
  385 
  386         return (0);
  387 
  388 fail:
  389 #ifdef RACCT
  390         if (racct_enable) {
  391                 PROC_LOCK(p);
  392                 racct_sub(p, RACCT_NTHR, 1);
  393                 PROC_UNLOCK(p);
  394         }
  395 #endif
  396         return (error);
  397 }
  398 
  399 int
  400 linux_clone(struct thread *td, struct linux_clone_args *args)
  401 {
  402 
  403         if (args->flags & LINUX_CLONE_THREAD)
  404                 return (linux_clone_thread(td, args));
  405         else
  406                 return (linux_clone_proc(td, args));
  407 }
  408 
  409 int
  410 linux_exit(struct thread *td, struct linux_exit_args *args)
  411 {
  412         struct linux_emuldata *em;
  413 
  414         em = em_find(td);
  415         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  416 
  417         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  418 
  419         umtx_thread_exit(td);
  420 
  421         linux_thread_detach(td);
  422 
  423         /*
  424          * XXX. When the last two threads of a process
  425          * exit via pthread_exit() try thr_exit() first.
  426          */
  427         kern_thr_exit(td);
  428         exit1(td, args->rval, 0);
  429                 /* NOTREACHED */
  430 }
  431 
  432 int
  433 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  434 {
  435         struct linux_emuldata *em;
  436 
  437         em = em_find(td);
  438         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  439 
  440         em->child_clear_tid = args->tidptr;
  441 
  442         td->td_retval[0] = em->em_tid;
  443 
  444         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  445             em->em_tid, args->tidptr, td->td_retval[0]);
  446 
  447         return (0);
  448 }
  449 
  450 void
  451 linux_thread_detach(struct thread *td)
  452 {
  453         struct linux_sys_futex_args cup;
  454         struct linux_emuldata *em;
  455         int *child_clear_tid;
  456         int error;
  457 
  458         em = em_find(td);
  459         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  460 
  461         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  462 
  463         release_futexes(td, em);
  464 
  465         child_clear_tid = em->child_clear_tid;
  466 
  467         if (child_clear_tid != NULL) {
  468 
  469                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  470                     em->em_tid, child_clear_tid);
  471 
  472                 error = suword32(child_clear_tid, 0);
  473                 if (error != 0)
  474                         return;
  475 
  476                 cup.uaddr = child_clear_tid;
  477                 cup.op = LINUX_FUTEX_WAKE;
  478                 cup.val = 1;            /* wake one */
  479                 cup.timeout = NULL;
  480                 cup.uaddr2 = NULL;
  481                 cup.val3 = 0;
  482                 error = linux_sys_futex(td, &cup);
  483                 /*
  484                  * this cannot happen at the moment and if this happens it
  485                  * probably means there is a user space bug
  486                  */
  487                 if (error != 0)
  488                         linux_msg(td, "futex stuff in thread_detach failed.");
  489         }
  490 }
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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
