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 
   96         return (0);
   97 }
   98 
   99 int
  100 linux_vfork(struct thread *td, struct linux_vfork_args *args)
  101 {
  102         struct fork_req fr;
  103         int error;
  104         struct proc *p2;
  105         struct thread *td2;
  106 
  107         bzero(&fr, sizeof(fr));
  108         fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
  109         fr.fr_procp = &p2;
  110         if ((error = fork1(td, &fr)) != 0)
  111                 return (error);
  112 
  113         td2 = FIRST_THREAD_IN_PROC(p2);
  114 
  115         linux_proc_init(td, td2, 0);
  116 
  117         td->td_retval[0] = p2->p_pid;
  118 
  119         /*
  120          * Make this runnable after we are finished with it.
  121          */
  122         thread_lock(td2);
  123         TD_SET_CAN_RUN(td2);
  124         sched_add(td2, SRQ_BORING);
  125 
  126         return (0);
  127 }
  128 #endif
  129 
  130 static int
  131 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
  132 {
  133         struct fork_req fr;
  134         int error, ff = RFPROC | RFSTOPPED, f2;
  135         struct proc *p2;
  136         struct thread *td2;
  137         int exit_signal;
  138         struct linux_emuldata *em;
  139 
  140         f2 = 0;
  141         exit_signal = args->flags & 0x000000ff;
  142         if (LINUX_SIG_VALID(exit_signal)) {
  143                 exit_signal = linux_to_bsd_signal(exit_signal);
  144         } else if (exit_signal != 0)
  145                 return (EINVAL);
  146 
  147         if (args->flags & LINUX_CLONE_VM)
  148                 ff |= RFMEM;
  149         if (args->flags & LINUX_CLONE_SIGHAND)
  150                 ff |= RFSIGSHARE;
  151         if (args->flags & LINUX_CLONE_FILES) {
  152                 if (!(args->flags & LINUX_CLONE_FS))
  153                         f2 |= FR2_SHARE_PATHS;
  154         } else {
  155                 ff |= RFFDG;
  156                 if (args->flags & LINUX_CLONE_FS)
  157                         f2 |= FR2_SHARE_PATHS;
  158         }
  159 
  160         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  161                 if (args->parent_tidptr == NULL)
  162                         return (EINVAL);
  163 
  164         if (args->flags & LINUX_CLONE_VFORK)
  165                 ff |= RFPPWAIT;
  166 
  167         bzero(&fr, sizeof(fr));
  168         fr.fr_flags = ff;
  169         fr.fr_flags2 = f2;
  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 
  232         td->td_retval[0] = p2->p_pid;
  233 
  234         return (0);
  235 }
  236 
  237 static int
  238 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
  239 {
  240         struct linux_emuldata *em;
  241         struct thread *newtd;
  242         struct proc *p;
  243         int error;
  244 
  245         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  246             td->td_tid, (unsigned)args->flags,
  247             args->parent_tidptr, args->child_tidptr);
  248 
  249         if ((args->flags & LINUX_CLONE_PARENT) != 0)
  250                 return (EINVAL);
  251         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  252                 if (args->parent_tidptr == NULL)
  253                         return (EINVAL);
  254 
  255         /* Threads should be created with own stack */
  256         if (args->stack == NULL)
  257                 return (EINVAL);
  258 
  259         p = td->td_proc;
  260 
  261 #ifdef RACCT
  262         if (racct_enable) {
  263                 PROC_LOCK(p);
  264                 error = racct_add(p, RACCT_NTHR, 1);
  265                 PROC_UNLOCK(p);
  266                 if (error != 0)
  267                         return (EPROCLIM);
  268         }
  269 #endif
  270 
  271         /* Initialize our td */
  272         error = kern_thr_alloc(p, 0, &newtd);
  273         if (error)
  274                 goto fail;
  275 
  276         cpu_copy_thread(newtd, td);
  277 
  278         bzero(&newtd->td_startzero,
  279             __rangeof(struct thread, td_startzero, td_endzero));
  280         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  281             __rangeof(struct thread, td_startcopy, td_endcopy));
  282 
  283         newtd->td_proc = p;
  284         thread_cow_get(newtd, td);
  285 
  286         /* create the emuldata */
  287         linux_proc_init(td, newtd, args->flags);
  288 
  289         em = em_find(newtd);
  290         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  291 
  292         if (args->flags & LINUX_CLONE_SETTLS)
  293                 linux_set_cloned_tls(newtd, args->tls);
  294 
  295         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  296                 em->child_set_tid = args->child_tidptr;
  297         else
  298                 em->child_set_tid = NULL;
  299 
  300         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  301                 em->child_clear_tid = args->child_tidptr;
  302         else
  303                 em->child_clear_tid = NULL;
  304 
  305         cpu_thread_clean(newtd);
  306 
  307         linux_set_upcall_kse(newtd, PTROUT(args->stack));
  308 
  309         PROC_LOCK(p);
  310         p->p_flag |= P_HADTHREADS;
  311         thread_link(newtd, p);
  312         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  313 
  314         thread_lock(td);
  315         /* let the scheduler know about these things. */
  316         sched_fork_thread(td, newtd);
  317         thread_unlock(td);
  318         if (P_SHOULDSTOP(p))
  319                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  320 
  321         if (p->p_ptevents & PTRACE_LWP)
  322                 newtd->td_dbgflags |= TDB_BORN;
  323         PROC_UNLOCK(p);
  324 
  325         tidhash_add(newtd);
  326 
  327         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  328             td->td_tid, newtd->td_tid);
  329 
  330         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  331                 error = copyout(&newtd->td_tid, args->parent_tidptr,
  332                     sizeof(newtd->td_tid));
  333                 if (error)
  334                         linux_msg(td, "clone_thread: copyout td_tid failed!");
  335         }
  336 
  337         /*
  338          * Make this runnable after we are finished with it.
  339          */
  340         thread_lock(newtd);
  341         TD_SET_CAN_RUN(newtd);
  342         sched_add(newtd, SRQ_BORING);
  343 
  344         td->td_retval[0] = newtd->td_tid;
  345 
  346         return (0);
  347 
  348 fail:
  349 #ifdef RACCT
  350         if (racct_enable) {
  351                 PROC_LOCK(p);
  352                 racct_sub(p, RACCT_NTHR, 1);
  353                 PROC_UNLOCK(p);
  354         }
  355 #endif
  356         return (error);
  357 }
  358 
  359 int
  360 linux_clone(struct thread *td, struct linux_clone_args *args)
  361 {
  362 
  363         if (args->flags & LINUX_CLONE_THREAD)
  364                 return (linux_clone_thread(td, args));
  365         else
  366                 return (linux_clone_proc(td, args));
  367 }
  368 
  369 int
  370 linux_exit(struct thread *td, struct linux_exit_args *args)
  371 {
  372         struct linux_emuldata *em;
  373 
  374         em = em_find(td);
  375         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  376 
  377         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  378 
  379         umtx_thread_exit(td);
  380 
  381         linux_thread_detach(td);
  382 
  383         /*
  384          * XXX. When the last two threads of a process
  385          * exit via pthread_exit() try thr_exit() first.
  386          */
  387         kern_thr_exit(td);
  388         exit1(td, args->rval, 0);
  389                 /* NOTREACHED */
  390 }
  391 
  392 int
  393 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  394 {
  395         struct linux_emuldata *em;
  396 
  397         em = em_find(td);
  398         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  399 
  400         em->child_clear_tid = args->tidptr;
  401 
  402         td->td_retval[0] = em->em_tid;
  403 
  404         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  405             em->em_tid, args->tidptr, td->td_retval[0]);
  406 
  407         return (0);
  408 }
  409 
  410 void
  411 linux_thread_detach(struct thread *td)
  412 {
  413         struct linux_sys_futex_args cup;
  414         struct linux_emuldata *em;
  415         int *child_clear_tid;
  416         int error;
  417 
  418         em = em_find(td);
  419         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  420 
  421         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  422 
  423         release_futexes(td, em);
  424 
  425         child_clear_tid = em->child_clear_tid;
  426 
  427         if (child_clear_tid != NULL) {
  428                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  429                     em->em_tid, child_clear_tid);
  430 
  431                 error = suword32(child_clear_tid, 0);
  432                 if (error != 0)
  433                         return;
  434 
  435                 cup.uaddr = child_clear_tid;
  436                 cup.op = LINUX_FUTEX_WAKE;
  437                 cup.val = 1;            /* wake one */
  438                 cup.timeout = NULL;
  439                 cup.uaddr2 = NULL;
  440                 cup.val3 = 0;
  441                 error = linux_sys_futex(td, &cup);
  442                 /*
  443                  * this cannot happen at the moment and if this happens it
  444                  * probably means there is a user space bug
  445                  */
  446                 if (error != 0)
  447                         linux_msg(td, "futex stuff in thread_detach failed.");
  448         }
  449 }
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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
