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/unistd.h>
   49 #include <sys/wait.h>
   50 
   51 #include <vm/vm.h>
   52 #include <vm/pmap.h>
   53 #include <vm/vm_map.h>
   54 
   55 #ifdef COMPAT_LINUX32
   56 #include <machine/../linux32/linux.h>
   57 #include <machine/../linux32/linux32_proto.h>
   58 #else
   59 #include <machine/../linux/linux.h>
   60 #include <machine/../linux/linux_proto.h>
   61 #endif
   62 #include <compat/linux/linux_emul.h>
   63 #include <compat/linux/linux_futex.h>
   64 #include <compat/linux/linux_misc.h>
   65 #include <compat/linux/linux_util.h>
   66 
   67 #ifdef LINUX_LEGACY_SYSCALLS
   68 int
   69 linux_fork(struct thread *td, struct linux_fork_args *args)
   70 {
   71         struct fork_req fr;
   72         int error;
   73         struct proc *p2;
   74         struct thread *td2;
   75 
   76         bzero(&fr, sizeof(fr));
   77         fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
   78         fr.fr_procp = &p2;
   79         if ((error = fork1(td, &fr)) != 0)
   80                 return (error);
   81 
   82         td2 = FIRST_THREAD_IN_PROC(p2);
   83 
   84         linux_proc_init(td, td2, 0);
   85 
   86         td->td_retval[0] = p2->p_pid;
   87 
   88         /*
   89          * Make this runnable after we are finished with it.
   90          */
   91         thread_lock(td2);
   92         TD_SET_CAN_RUN(td2);
   93         sched_add(td2, SRQ_BORING);
   94 
   95         return (0);
   96 }
   97 
   98 int
   99 linux_vfork(struct thread *td, struct linux_vfork_args *args)
  100 {
  101         struct fork_req fr;
  102         int error;
  103         struct proc *p2;
  104         struct thread *td2;
  105 
  106         bzero(&fr, sizeof(fr));
  107         fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
  108         fr.fr_procp = &p2;
  109         if ((error = fork1(td, &fr)) != 0)
  110                 return (error);
  111 
  112         td2 = FIRST_THREAD_IN_PROC(p2);
  113 
  114         linux_proc_init(td, td2, 0);
  115 
  116         td->td_retval[0] = p2->p_pid;
  117 
  118         /*
  119          * Make this runnable after we are finished with it.
  120          */
  121         thread_lock(td2);
  122         TD_SET_CAN_RUN(td2);
  123         sched_add(td2, SRQ_BORING);
  124 
  125         return (0);
  126 }
  127 #endif
  128 
  129 static int
  130 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
  131 {
  132         struct fork_req fr;
  133         int error, ff = RFPROC | RFSTOPPED, f2;
  134         struct proc *p2;
  135         struct thread *td2;
  136         int exit_signal;
  137         struct linux_emuldata *em;
  138 
  139         f2 = 0;
  140         exit_signal = args->flags & 0x000000ff;
  141         if (LINUX_SIG_VALID(exit_signal)) {
  142                 exit_signal = linux_to_bsd_signal(exit_signal);
  143         } else if (exit_signal != 0)
  144                 return (EINVAL);
  145 
  146         if (args->flags & LINUX_CLONE_VM)
  147                 ff |= RFMEM;
  148         if (args->flags & LINUX_CLONE_SIGHAND)
  149                 ff |= RFSIGSHARE;
  150         if (args->flags & LINUX_CLONE_FILES) {
  151                 if (!(args->flags & LINUX_CLONE_FS))
  152                         f2 |= FR2_SHARE_PATHS;
  153         } else {
  154                 ff |= RFFDG;
  155                 if (args->flags & LINUX_CLONE_FS)
  156                         f2 |= FR2_SHARE_PATHS;
  157         }
  158 
  159         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  160                 if (args->parent_tidptr == NULL)
  161                         return (EINVAL);
  162 
  163         if (args->flags & LINUX_CLONE_VFORK)
  164                 ff |= RFPPWAIT;
  165 
  166         bzero(&fr, sizeof(fr));
  167         fr.fr_flags = ff;
  168         fr.fr_flags2 = f2;
  169         fr.fr_procp = &p2;
  170         error = fork1(td, &fr);
  171         if (error)
  172                 return (error);
  173 
  174         td2 = FIRST_THREAD_IN_PROC(p2);
  175 
  176         /* create the emuldata */
  177         linux_proc_init(td, td2, args->flags);
  178 
  179         em = em_find(td2);
  180         KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
  181 
  182         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  183                 em->child_set_tid = args->child_tidptr;
  184         else
  185                 em->child_set_tid = NULL;
  186 
  187         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  188                 em->child_clear_tid = args->child_tidptr;
  189         else
  190                 em->child_clear_tid = NULL;
  191 
  192         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  193                 error = copyout(&p2->p_pid, args->parent_tidptr,
  194                     sizeof(p2->p_pid));
  195                 if (error)
  196                         linux_msg(td, "copyout p_pid failed!");
  197         }
  198 
  199         PROC_LOCK(p2);
  200         p2->p_sigparent = exit_signal;
  201         PROC_UNLOCK(p2);
  202         /*
  203          * In a case of stack = NULL, we are supposed to COW calling process
  204          * stack. This is what normal fork() does, so we just keep tf_rsp arg
  205          * intact.
  206          */
  207         linux_set_upcall(td2, PTROUT(args->stack));
  208 
  209         if (args->flags & LINUX_CLONE_SETTLS)
  210                 linux_set_cloned_tls(td2, args->tls);
  211 
  212         /*
  213          * If CLONE_PARENT is set, then the parent of the new process will be
  214          * the same as that of the calling process.
  215          */
  216         if (args->flags & LINUX_CLONE_PARENT) {
  217                 sx_xlock(&proctree_lock);
  218                 PROC_LOCK(p2);
  219                 proc_reparent(p2, td->td_proc->p_pptr, true);
  220                 PROC_UNLOCK(p2);
  221                 sx_xunlock(&proctree_lock);
  222         }
  223 
  224         /*
  225          * Make this runnable after we are finished with it.
  226          */
  227         thread_lock(td2);
  228         TD_SET_CAN_RUN(td2);
  229         sched_add(td2, SRQ_BORING);
  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         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  245             td->td_tid, (unsigned)args->flags,
  246             args->parent_tidptr, args->child_tidptr);
  247 
  248         if ((args->flags & LINUX_CLONE_PARENT) != 0)
  249                 return (EINVAL);
  250         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  251                 if (args->parent_tidptr == NULL)
  252                         return (EINVAL);
  253 
  254         /* Threads should be created with own stack */
  255         if (args->stack == NULL)
  256                 return (EINVAL);
  257 
  258         p = td->td_proc;
  259 
  260 #ifdef RACCT
  261         if (racct_enable) {
  262                 PROC_LOCK(p);
  263                 error = racct_add(p, RACCT_NTHR, 1);
  264                 PROC_UNLOCK(p);
  265                 if (error != 0)
  266                         return (EPROCLIM);
  267         }
  268 #endif
  269 
  270         /* Initialize our td */
  271         error = kern_thr_alloc(p, 0, &newtd);
  272         if (error)
  273                 goto fail;
  274 
  275         cpu_copy_thread(newtd, td);
  276 
  277         bzero(&newtd->td_startzero,
  278             __rangeof(struct thread, td_startzero, td_endzero));
  279         bcopy(&td->td_startcopy, &newtd->td_startcopy,
  280             __rangeof(struct thread, td_startcopy, td_endcopy));
  281 
  282         newtd->td_proc = p;
  283         thread_cow_get(newtd, td);
  284 
  285         /* create the emuldata */
  286         linux_proc_init(td, newtd, args->flags);
  287 
  288         em = em_find(newtd);
  289         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  290 
  291         if (args->flags & LINUX_CLONE_SETTLS)
  292                 linux_set_cloned_tls(newtd, args->tls);
  293 
  294         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  295                 em->child_set_tid = args->child_tidptr;
  296         else
  297                 em->child_set_tid = NULL;
  298 
  299         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  300                 em->child_clear_tid = args->child_tidptr;
  301         else
  302                 em->child_clear_tid = NULL;
  303 
  304         cpu_thread_clean(newtd);
  305 
  306         linux_set_upcall(newtd, PTROUT(args->stack));
  307 
  308         PROC_LOCK(p);
  309         p->p_flag |= P_HADTHREADS;
  310         thread_link(newtd, p);
  311         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  312 
  313         thread_lock(td);
  314         /* let the scheduler know about these things. */
  315         sched_fork_thread(td, newtd);
  316         thread_unlock(td);
  317         if (P_SHOULDSTOP(p))
  318                 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
  319 
  320         if (p->p_ptevents & PTRACE_LWP)
  321                 newtd->td_dbgflags |= TDB_BORN;
  322         PROC_UNLOCK(p);
  323 
  324         tidhash_add(newtd);
  325 
  326         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  327             td->td_tid, newtd->td_tid);
  328 
  329         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  330                 error = copyout(&newtd->td_tid, args->parent_tidptr,
  331                     sizeof(newtd->td_tid));
  332                 if (error)
  333                         linux_msg(td, "clone_thread: copyout td_tid failed!");
  334         }
  335 
  336         /*
  337          * Make this runnable after we are finished with it.
  338          */
  339         thread_lock(newtd);
  340         TD_SET_CAN_RUN(newtd);
  341         sched_add(newtd, SRQ_BORING);
  342 
  343         td->td_retval[0] = newtd->td_tid;
  344 
  345         return (0);
  346 
  347 fail:
  348 #ifdef RACCT
  349         if (racct_enable) {
  350                 PROC_LOCK(p);
  351                 racct_sub(p, RACCT_NTHR, 1);
  352                 PROC_UNLOCK(p);
  353         }
  354 #endif
  355         return (error);
  356 }
  357 
  358 int
  359 linux_clone(struct thread *td, struct linux_clone_args *args)
  360 {
  361 
  362         if (args->flags & LINUX_CLONE_THREAD)
  363                 return (linux_clone_thread(td, args));
  364         else
  365                 return (linux_clone_proc(td, args));
  366 }
  367 
  368 int
  369 linux_exit(struct thread *td, struct linux_exit_args *args)
  370 {
  371         struct linux_emuldata *em;
  372 
  373         em = em_find(td);
  374         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  375 
  376         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  377 
  378         linux_thread_detach(td);
  379 
  380         /*
  381          * XXX. When the last two threads of a process
  382          * exit via pthread_exit() try thr_exit() first.
  383          */
  384         kern_thr_exit(td);
  385         exit1(td, args->rval, 0);
  386                 /* NOTREACHED */
  387 }
  388 
  389 int
  390 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  391 {
  392         struct linux_emuldata *em;
  393 
  394         em = em_find(td);
  395         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  396 
  397         em->child_clear_tid = args->tidptr;
  398 
  399         td->td_retval[0] = em->em_tid;
  400 
  401         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  402             em->em_tid, args->tidptr, td->td_retval[0]);
  403 
  404         return (0);
  405 }
  406 
  407 void
  408 linux_thread_detach(struct thread *td)
  409 {
  410         struct linux_sys_futex_args cup;
  411         struct linux_emuldata *em;
  412         int *child_clear_tid;
  413         int error;
  414 
  415         em = em_find(td);
  416         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  417 
  418         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  419 
  420         release_futexes(td, em);
  421 
  422         child_clear_tid = em->child_clear_tid;
  423 
  424         if (child_clear_tid != NULL) {
  425                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  426                     em->em_tid, child_clear_tid);
  427 
  428                 error = suword32(child_clear_tid, 0);
  429                 if (error != 0)
  430                         return;
  431 
  432                 cup.uaddr = child_clear_tid;
  433                 cup.op = LINUX_FUTEX_WAKE;
  434                 cup.val = 1;            /* wake one */
  435                 cup.timeout = NULL;
  436                 cup.uaddr2 = NULL;
  437                 cup.val3 = 0;
  438                 error = linux_sys_futex(td, &cup);
  439                 /*
  440                  * this cannot happen at the moment and if this happens it
  441                  * probably means there is a user space bug
  442                  */
  443                 if (error != 0)
  444                         linux_msg(td, "futex stuff in thread_detach failed.");
  445         }
  446 }
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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
