linux_fork.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2004 Tim J. Robbins
    5  * Copyright (c) 2002 Doug Rabson
    6  * Copyright (c) 2000 Marcel Moolenaar
    7  * All rights reserved.
    8  *
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer
   14  *    in this position and unchanged.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD$");
   33 
   34 #include "opt_compat.h"
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/imgact.h>
   39 #include <sys/ktr.h>
   40 #include <sys/lock.h>
   41 #include <sys/mutex.h>
   42 #include <sys/proc.h>
   43 #include <sys/ptrace.h>
   44 #include <sys/racct.h>
   45 #include <sys/sched.h>
   46 #include <sys/syscallsubr.h>
   47 #include <sys/sx.h>
   48 #include <sys/umtx.h>
   49 #include <sys/unistd.h>
   50 #include <sys/wait.h>
   51 
   52 #include <vm/vm.h>
   53 #include <vm/pmap.h>
   54 #include <vm/vm_map.h>
   55 
   56 #ifdef COMPAT_LINUX32
   57 #include <machine/../linux32/linux.h>
   58 #include <machine/../linux32/linux32_proto.h>
   59 #else
   60 #include <machine/../linux/linux.h>
   61 #include <machine/../linux/linux_proto.h>
   62 #endif
   63 #include <compat/linux/linux_emul.h>
   64 #include <compat/linux/linux_futex.h>
   65 #include <compat/linux/linux_misc.h>
   66 #include <compat/linux/linux_util.h>
   67 
   68 #ifdef LINUX_LEGACY_SYSCALLS
   69 int
   70 linux_fork(struct thread *td, struct linux_fork_args *args)
   71 {
   72         struct fork_req fr;
   73         int error;
   74         struct proc *p2;
   75         struct thread *td2;
   76 
   77         bzero(&fr, sizeof(fr));
   78         fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
   79         fr.fr_procp = &p2;
   80         if ((error = fork1(td, &fr)) != 0)
   81                 return (error);
   82 
   83         td2 = FIRST_THREAD_IN_PROC(p2);
   84 
   85         linux_proc_init(td, td2, 0);
   86 
   87         td->td_retval[0] = p2->p_pid;
   88 
   89         /*
   90          * Make this runnable after we are finished with it.
   91          */
   92         thread_lock(td2);
   93         TD_SET_CAN_RUN(td2);
   94         sched_add(td2, SRQ_BORING);
   95         thread_unlock(td2);
   96 
   97         return (0);
   98 }
   99 
  100 int
  101 linux_vfork(struct thread *td, struct linux_vfork_args *args)
  102 {
  103         struct fork_req fr;
  104         int error;
  105         struct proc *p2;
  106         struct thread *td2;
  107 
  108         bzero(&fr, sizeof(fr));
  109         fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
  110         fr.fr_procp = &p2;
  111         if ((error = fork1(td, &fr)) != 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 #endif
  131 
  132 static int
  133 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
  134 {
  135         struct fork_req fr;
  136         int error, ff = RFPROC | RFSTOPPED;
  137         struct proc *p2;
  138         struct thread *td2;
  139         int exit_signal;
  140         struct linux_emuldata *em;
  141 
  142         exit_signal = args->flags & 0x000000ff;
  143         if (LINUX_SIG_VALID(exit_signal)) {
  144                 exit_signal = linux_to_bsd_signal(exit_signal);
  145         } else if (exit_signal != 0)
  146                 return (EINVAL);
  147 
  148         if (args->flags & LINUX_CLONE_VM)
  149                 ff |= RFMEM;
  150         if (args->flags & LINUX_CLONE_SIGHAND)
  151                 ff |= RFSIGSHARE;
  152         /*
  153          * XXX: In Linux, sharing of fs info (chroot/cwd/umask)
  154          * and open files is independent.  In FreeBSD, its in one
  155          * structure but in reality it does not cause any problems
  156          * because both of these flags are usually set together.
  157          */
  158         if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS)))
  159                 ff |= RFFDG;
  160 
  161         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  162                 if (args->parent_tidptr == NULL)
  163                         return (EINVAL);
  164 
  165         if (args->flags & LINUX_CLONE_VFORK)
  166                 ff |= RFPPWAIT;
  167 
  168         bzero(&fr, sizeof(fr));
  169         fr.fr_flags = ff;
  170         fr.fr_procp = &p2;
  171         error = fork1(td, &fr);
  172         if (error)
  173                 return (error);
  174 
  175         td2 = FIRST_THREAD_IN_PROC(p2);
  176 
  177         /* create the emuldata */
  178         linux_proc_init(td, td2, args->flags);
  179 
  180         em = em_find(td2);
  181         KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
  182 
  183         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  184                 em->child_set_tid = args->child_tidptr;
  185         else
  186                 em->child_set_tid = NULL;
  187 
  188         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  189                 em->child_clear_tid = args->child_tidptr;
  190         else
  191                 em->child_clear_tid = NULL;
  192 
  193         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  194                 error = copyout(&p2->p_pid, args->parent_tidptr,
  195                     sizeof(p2->p_pid));
  196                 if (error)
  197                         linux_msg(td, "copyout p_pid failed!");
  198         }
  199 
  200         PROC_LOCK(p2);
  201         p2->p_sigparent = exit_signal;
  202         PROC_UNLOCK(p2);
  203         /*
  204          * In a case of stack = NULL, we are supposed to COW calling process
  205          * stack. This is what normal fork() does, so we just keep tf_rsp arg
  206          * intact.
  207          */
  208         linux_set_upcall_kse(td2, PTROUT(args->stack));
  209 
  210         if (args->flags & LINUX_CLONE_SETTLS)
  211                 linux_set_cloned_tls(td2, args->tls);
  212 
  213         /*
  214          * If CLONE_PARENT is set, then the parent of the new process will be
  215          * the same as that of the calling process.
  216          */
  217         if (args->flags & LINUX_CLONE_PARENT) {
  218                 sx_xlock(&proctree_lock);
  219                 PROC_LOCK(p2);
  220                 proc_reparent(p2, td->td_proc->p_pptr, true);
  221                 PROC_UNLOCK(p2);
  222                 sx_xunlock(&proctree_lock);
  223         }
  224 
  225         /*
  226          * Make this runnable after we are finished with it.
  227          */
  228         thread_lock(td2);
  229         TD_SET_CAN_RUN(td2);
  230         sched_add(td2, SRQ_BORING);
  231         thread_unlock(td2);
  232 
  233         td->td_retval[0] = p2->p_pid;
  234 
  235         return (0);
  236 }
  237 
  238 static int
  239 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
  240 {
  241         struct linux_emuldata *em;
  242         struct thread *newtd;
  243         struct proc *p;
  244         int error;
  245 
  246         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  247             td->td_tid, (unsigned)args->flags,
  248             args->parent_tidptr, args->child_tidptr);
  249 
  250         if ((args->flags & LINUX_CLONE_PARENT) != 0)
  251                 return (EINVAL);
  252         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  253                 if (args->parent_tidptr == NULL)
  254                         return (EINVAL);
  255 
  256         /* Threads should be created with own stack */
  257         if (args->stack == NULL)
  258                 return (EINVAL);
  259 
  260         p = td->td_proc;
  261 
  262 #ifdef RACCT
  263         if (racct_enable) {
  264                 PROC_LOCK(p);
  265                 error = racct_add(p, RACCT_NTHR, 1);
  266                 PROC_UNLOCK(p);
  267                 if (error != 0)
  268                         return (EPROCLIM);
  269         }
  270 #endif
  271 
  272         /* Initialize our td */
  273         error = kern_thr_alloc(p, 0, &newtd);
  274         if (error)
  275                 goto fail;
  276 
  277         cpu_copy_thread(newtd, td);
  278 
  279         bzero(&newtd->td_startzero,
  280             __rangeof(struct thread, td_startzero, td_endzero));
  281         newtd->td_pflags2 = 0;
  282         newtd->td_errno = 0;
  283         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  284             __rangeof(struct thread, td_startcopy, td_endcopy));
  285 
  286         newtd->td_proc = p;
  287         thread_cow_get(newtd, td);
  288 
  289         /* create the emuldata */
  290         linux_proc_init(td, newtd, args->flags);
  291 
  292         em = em_find(newtd);
  293         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  294 
  295         if (args->flags & LINUX_CLONE_SETTLS)
  296                 linux_set_cloned_tls(newtd, args->tls);
  297 
  298         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  299                 em->child_set_tid = args->child_tidptr;
  300         else
  301                 em->child_set_tid = NULL;
  302 
  303         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  304                 em->child_clear_tid = args->child_tidptr;
  305         else
  306                 em->child_clear_tid = NULL;
  307 
  308         cpu_thread_clean(newtd);
  309 
  310         linux_set_upcall_kse(newtd, PTROUT(args->stack));
  311 
  312         PROC_LOCK(p);
  313         p->p_flag |= P_HADTHREADS;
  314         thread_link(newtd, p);
  315         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  316 
  317         thread_lock(td);
  318         /* let the scheduler know about these things. */
  319         sched_fork_thread(td, newtd);
  320         thread_unlock(td);
  321         if (P_SHOULDSTOP(p))
  322                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  323 
  324         if (p->p_ptevents & PTRACE_LWP)
  325                 newtd->td_dbgflags |= TDB_BORN;
  326         PROC_UNLOCK(p);
  327 
  328         tidhash_add(newtd);
  329 
  330         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  331             td->td_tid, newtd->td_tid);
  332 
  333         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  334                 error = copyout(&newtd->td_tid, args->parent_tidptr,
  335                     sizeof(newtd->td_tid));
  336                 if (error)
  337                         linux_msg(td, "clone_thread: copyout td_tid failed!");
  338         }
  339 
  340         /*
  341          * Make this runnable after we are finished with it.
  342          */
  343         thread_lock(newtd);
  344         TD_SET_CAN_RUN(newtd);
  345         sched_add(newtd, SRQ_BORING);
  346         thread_unlock(newtd);
  347 
  348         td->td_retval[0] = newtd->td_tid;
  349 
  350         return (0);
  351 
  352 fail:
  353 #ifdef RACCT
  354         if (racct_enable) {
  355                 PROC_LOCK(p);
  356                 racct_sub(p, RACCT_NTHR, 1);
  357                 PROC_UNLOCK(p);
  358         }
  359 #endif
  360         return (error);
  361 }
  362 
  363 int
  364 linux_clone(struct thread *td, struct linux_clone_args *args)
  365 {
  366 
  367         if (args->flags & LINUX_CLONE_THREAD)
  368                 return (linux_clone_thread(td, args));
  369         else
  370                 return (linux_clone_proc(td, args));
  371 }
  372 
  373 int
  374 linux_exit(struct thread *td, struct linux_exit_args *args)
  375 {
  376         struct linux_emuldata *em;
  377 
  378         em = em_find(td);
  379         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  380 
  381         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  382 
  383         umtx_thread_exit(td);
  384 
  385         linux_thread_detach(td);
  386 
  387         /*
  388          * XXX. When the last two threads of a process
  389          * exit via pthread_exit() try thr_exit() first.
  390          */
  391         kern_thr_exit(td);
  392         exit1(td, args->rval, 0);
  393                 /* NOTREACHED */
  394 }
  395 
  396 int
  397 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  398 {
  399         struct linux_emuldata *em;
  400 
  401         em = em_find(td);
  402         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  403 
  404         em->child_clear_tid = args->tidptr;
  405 
  406         td->td_retval[0] = em->em_tid;
  407 
  408         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  409             em->em_tid, args->tidptr, td->td_retval[0]);
  410 
  411         return (0);
  412 }
  413 
  414 void
  415 linux_thread_detach(struct thread *td)
  416 {
  417         struct linux_sys_futex_args cup;
  418         struct linux_emuldata *em;
  419         int *child_clear_tid;
  420         int error;
  421 
  422         em = em_find(td);
  423         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  424 
  425         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  426 
  427         release_futexes(td, em);
  428 
  429         child_clear_tid = em->child_clear_tid;
  430 
  431         if (child_clear_tid != NULL) {
  432 
  433                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  434                     em->em_tid, child_clear_tid);
  435 
  436                 error = suword32(child_clear_tid, 0);
  437                 if (error != 0)
  438                         return;
  439 
  440                 cup.uaddr = child_clear_tid;
  441                 cup.op = LINUX_FUTEX_WAKE;
  442                 cup.val = 1;            /* wake one */
  443                 cup.timeout = NULL;
  444                 cup.uaddr2 = NULL;
  445                 cup.val3 = 0;
  446                 error = linux_sys_futex(td, &cup);
  447                 /*
  448                  * this cannot happen at the moment and if this happens it
  449                  * probably means there is a user space bug
  450                  */
  451                 if (error != 0)
  452                         linux_msg(td, "futex stuff in thread_detach failed.");
  453         }
  454 }
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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
