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/umtxvar.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.h>
   64 #include <compat/linux/linux_emul.h>
   65 #include <compat/linux/linux_fork.h>
   66 #include <compat/linux/linux_futex.h>
   67 #include <compat/linux/linux_mib.h>
   68 #include <compat/linux/linux_misc.h>
   69 #include <compat/linux/linux_util.h>
   70 
   71 #ifdef LINUX_LEGACY_SYSCALLS
   72 int
   73 linux_fork(struct thread *td, struct linux_fork_args *args)
   74 {
   75         struct fork_req fr;
   76         int error;
   77         struct proc *p2;
   78         struct thread *td2;
   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, false);
   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 
   99         return (0);
  100 }
  101 
  102 int
  103 linux_vfork(struct thread *td, struct linux_vfork_args *args)
  104 {
  105         struct fork_req fr;
  106         int error;
  107         struct proc *p2;
  108         struct thread *td2;
  109 
  110         bzero(&fr, sizeof(fr));
  111         fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
  112         fr.fr_procp = &p2;
  113         if ((error = fork1(td, &fr)) != 0)
  114                 return (error);
  115 
  116         td2 = FIRST_THREAD_IN_PROC(p2);
  117 
  118         linux_proc_init(td, td2, false);
  119 
  120         td->td_retval[0] = p2->p_pid;
  121 
  122         /*
  123          * Make this runnable after we are finished with it.
  124          */
  125         thread_lock(td2);
  126         TD_SET_CAN_RUN(td2);
  127         sched_add(td2, SRQ_BORING);
  128 
  129         return (0);
  130 }
  131 #endif
  132 
  133 static int
  134 linux_clone_proc(struct thread *td, struct l_clone_args *args)
  135 {
  136         struct fork_req fr;
  137         int error, ff, f2;
  138         struct proc *p2;
  139         struct thread *td2;
  140         int exit_signal;
  141         struct linux_emuldata *em;
  142 
  143         f2 = 0;
  144         ff = RFPROC | RFSTOPPED;
  145         if (LINUX_SIG_VALID(args->exit_signal)) {
  146                 exit_signal = linux_to_bsd_signal(args->exit_signal);
  147         } else if (args->exit_signal != 0)
  148                 return (EINVAL);
  149         else
  150                 exit_signal = 0;
  151 
  152         if (args->flags & LINUX_CLONE_VM)
  153                 ff |= RFMEM;
  154         if (args->flags & LINUX_CLONE_SIGHAND)
  155                 ff |= RFSIGSHARE;
  156         if ((args->flags & LINUX_CLONE_CLEAR_SIGHAND) != 0)
  157                 f2 |= FR2_DROPSIG_CAUGHT;
  158         if (args->flags & LINUX_CLONE_FILES) {
  159                 if (!(args->flags & LINUX_CLONE_FS))
  160                         f2 |= FR2_SHARE_PATHS;
  161         } else {
  162                 ff |= RFFDG;
  163                 if (args->flags & LINUX_CLONE_FS)
  164                         f2 |= FR2_SHARE_PATHS;
  165         }
  166 
  167         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  168                 if (args->parent_tid == NULL)
  169                         return (EINVAL);
  170 
  171         if (args->flags & LINUX_CLONE_VFORK)
  172                 ff |= RFPPWAIT;
  173 
  174         bzero(&fr, sizeof(fr));
  175         fr.fr_flags = ff;
  176         fr.fr_flags2 = f2;
  177         fr.fr_procp = &p2;
  178         error = fork1(td, &fr);
  179         if (error)
  180                 return (error);
  181 
  182         td2 = FIRST_THREAD_IN_PROC(p2);
  183 
  184         /* create the emuldata */
  185         linux_proc_init(td, td2, false);
  186 
  187         em = em_find(td2);
  188         KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
  189 
  190         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  191                 em->child_set_tid = args->child_tid;
  192         else
  193                 em->child_set_tid = NULL;
  194 
  195         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  196                 em->child_clear_tid = args->child_tid;
  197         else
  198                 em->child_clear_tid = NULL;
  199 
  200         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  201                 error = copyout(&p2->p_pid, args->parent_tid,
  202                     sizeof(p2->p_pid));
  203                 if (error)
  204                         linux_msg(td, "copyout p_pid failed!");
  205         }
  206 
  207         PROC_LOCK(p2);
  208         p2->p_sigparent = exit_signal;
  209         PROC_UNLOCK(p2);
  210         /*
  211          * In a case of stack = NULL, we are supposed to COW calling process
  212          * stack. This is what normal fork() does, so we just keep tf_rsp arg
  213          * intact.
  214          */
  215         linux_set_upcall(td2, args->stack);
  216 
  217         if (args->flags & LINUX_CLONE_SETTLS)
  218                 linux_set_cloned_tls(td2, PTRIN(args->tls));
  219 
  220         /*
  221          * If CLONE_PARENT is set, then the parent of the new process will be
  222          * the same as that of the calling process.
  223          */
  224         if (args->flags & LINUX_CLONE_PARENT) {
  225                 sx_xlock(&proctree_lock);
  226                 PROC_LOCK(p2);
  227                 proc_reparent(p2, td->td_proc->p_pptr, true);
  228                 PROC_UNLOCK(p2);
  229                 sx_xunlock(&proctree_lock);
  230         }
  231 
  232         /*
  233          * Make this runnable after we are finished with it.
  234          */
  235         thread_lock(td2);
  236         TD_SET_CAN_RUN(td2);
  237         sched_add(td2, SRQ_BORING);
  238 
  239         td->td_retval[0] = p2->p_pid;
  240 
  241         return (0);
  242 }
  243 
  244 static int
  245 linux_clone_thread(struct thread *td, struct l_clone_args *args)
  246 {
  247         struct linux_emuldata *em;
  248         struct thread *newtd;
  249         struct proc *p;
  250         int error;
  251 
  252         LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
  253             td->td_tid, (unsigned)args->flags,
  254             args->parent_tid, args->child_tid);
  255 
  256         if ((args->flags & LINUX_CLONE_PARENT) != 0)
  257                 return (EINVAL);
  258         if (args->flags & LINUX_CLONE_PARENT_SETTID)
  259                 if (args->parent_tid == NULL)
  260                         return (EINVAL);
  261 
  262         /* Threads should be created with own stack */
  263         if (PTRIN(args->stack) == NULL)
  264                 return (EINVAL);
  265 
  266         p = td->td_proc;
  267 
  268 #ifdef RACCT
  269         if (racct_enable) {
  270                 PROC_LOCK(p);
  271                 error = racct_add(p, RACCT_NTHR, 1);
  272                 PROC_UNLOCK(p);
  273                 if (error != 0)
  274                         return (EPROCLIM);
  275         }
  276 #endif
  277 
  278         /* Initialize our td */
  279         error = kern_thr_alloc(p, 0, &newtd);
  280         if (error)
  281                 goto fail;
  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         thread_cow_get(newtd, td);
  290 
  291         cpu_copy_thread(newtd, td);
  292 
  293         /* create the emuldata */
  294         linux_proc_init(td, newtd, true);
  295 
  296         em = em_find(newtd);
  297         KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
  298 
  299         if (args->flags & LINUX_CLONE_SETTLS)
  300                 linux_set_cloned_tls(newtd, PTRIN(args->tls));
  301 
  302         if (args->flags & LINUX_CLONE_CHILD_SETTID)
  303                 em->child_set_tid = args->child_tid;
  304         else
  305                 em->child_set_tid = NULL;
  306 
  307         if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
  308                 em->child_clear_tid = args->child_tid;
  309         else
  310                 em->child_clear_tid = NULL;
  311 
  312         cpu_thread_clean(newtd);
  313 
  314         linux_set_upcall(newtd, args->stack);
  315 
  316         PROC_LOCK(p);
  317         p->p_flag |= P_HADTHREADS;
  318         thread_link(newtd, p);
  319         bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
  320 
  321         thread_lock(td);
  322         /* let the scheduler know about these things. */
  323         sched_fork_thread(td, newtd);
  324         thread_unlock(td);
  325         if (P_SHOULDSTOP(p))
  326                 ast_sched(newtd, TDA_SUSPEND);
  327 
  328         if (p->p_ptevents & PTRACE_LWP)
  329                 newtd->td_dbgflags |= TDB_BORN;
  330         PROC_UNLOCK(p);
  331 
  332         tidhash_add(newtd);
  333 
  334         LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
  335             td->td_tid, newtd->td_tid);
  336 
  337         if (args->flags & LINUX_CLONE_PARENT_SETTID) {
  338                 error = copyout(&newtd->td_tid, args->parent_tid,
  339                     sizeof(newtd->td_tid));
  340                 if (error)
  341                         linux_msg(td, "clone_thread: copyout td_tid failed!");
  342         }
  343 
  344         /*
  345          * Make this runnable after we are finished with it.
  346          */
  347         thread_lock(newtd);
  348         TD_SET_CAN_RUN(newtd);
  349         sched_add(newtd, SRQ_BORING);
  350 
  351         td->td_retval[0] = newtd->td_tid;
  352 
  353         return (0);
  354 
  355 fail:
  356 #ifdef RACCT
  357         if (racct_enable) {
  358                 PROC_LOCK(p);
  359                 racct_sub(p, RACCT_NTHR, 1);
  360                 PROC_UNLOCK(p);
  361         }
  362 #endif
  363         return (error);
  364 }
  365 
  366 int
  367 linux_clone(struct thread *td, struct linux_clone_args *args)
  368 {
  369         struct l_clone_args ca = {
  370                 .flags = (lower_32_bits(args->flags) & ~LINUX_CSIGNAL),
  371                 .child_tid = args->child_tidptr,
  372                 .parent_tid = args->parent_tidptr,
  373                 .exit_signal = (lower_32_bits(args->flags) & LINUX_CSIGNAL),
  374                 .stack = args->stack,
  375                 .tls = args->tls,
  376         };
  377 
  378         if (args->flags & LINUX_CLONE_THREAD)
  379                 return (linux_clone_thread(td, &ca));
  380         else
  381                 return (linux_clone_proc(td, &ca));
  382 }
  383 
  384 
  385 static int
  386 linux_clone3_args_valid(struct l_user_clone_args *uca)
  387 {
  388 
  389         /* Verify that no unknown flags are passed along. */
  390         if ((uca->flags & ~(LINUX_CLONE_LEGACY_FLAGS |
  391             LINUX_CLONE_CLEAR_SIGHAND | LINUX_CLONE_INTO_CGROUP)) != 0)
  392                 return (EINVAL);
  393         if ((uca->flags & (LINUX_CLONE_DETACHED | LINUX_CSIGNAL)) != 0)
  394                 return (EINVAL);
  395 
  396         if ((uca->flags & (LINUX_CLONE_SIGHAND | LINUX_CLONE_CLEAR_SIGHAND)) ==
  397             (LINUX_CLONE_SIGHAND | LINUX_CLONE_CLEAR_SIGHAND))
  398                 return (EINVAL);
  399         if ((uca->flags & (LINUX_CLONE_THREAD | LINUX_CLONE_PARENT)) != 0 &&
  400             uca->exit_signal != 0)
  401                 return (EINVAL);
  402 
  403         /* We don't support set_tid, only validate input. */
  404         if (uca->set_tid_size > LINUX_MAX_PID_NS_LEVEL)
  405                 return (EINVAL);
  406         if (uca->set_tid == 0 && uca->set_tid_size > 0)
  407                 return (EINVAL);
  408         if (uca->set_tid != 0 && uca->set_tid_size == 0)
  409                 return (EINVAL);
  410 
  411         if (uca->stack == 0 && uca->stack_size > 0)
  412                 return (EINVAL);
  413         if (uca->stack != 0 && uca->stack_size == 0)
  414                 return (EINVAL);
  415 
  416         /* Verify that higher 32bits of exit_signal are unset. */
  417         if ((uca->exit_signal & ~(uint64_t)LINUX_CSIGNAL) != 0)
  418                 return (EINVAL);
  419 
  420         /* Verify that no unsupported flags are passed along. */
  421         if ((uca->flags & LINUX_CLONE_NEWTIME) != 0) {
  422                 LINUX_RATELIMIT_MSG("unsupported clone3 option CLONE_NEWTIME");
  423                 return (ENOSYS);
  424         }
  425         if ((uca->flags & LINUX_CLONE_INTO_CGROUP) != 0) {
  426                 LINUX_RATELIMIT_MSG("unsupported clone3 option CLONE_INTO_CGROUP");
  427                 return (ENOSYS);
  428         }
  429         if (uca->set_tid != 0 || uca->set_tid_size != 0) {
  430                 LINUX_RATELIMIT_MSG("unsupported clone3 set_tid");
  431                 return (ENOSYS);
  432         }
  433 
  434         return (0);
  435 }
  436 
  437 int
  438 linux_clone3(struct thread *td, struct linux_clone3_args *args)
  439 {
  440         struct l_user_clone_args *uca;
  441         struct l_clone_args *ca;
  442         size_t size;
  443         int error;
  444 
  445         if (args->usize > PAGE_SIZE)
  446                 return (E2BIG);
  447         if (args->usize < LINUX_CLONE_ARGS_SIZE_VER0)
  448                 return (EINVAL);
  449 
  450         /*
  451          * usize can be less than size of struct clone_args, to avoid using
  452          * of uninitialized data of struct clone_args, allocate at least
  453          * sizeof(struct clone_args) storage and zero it.
  454          */
  455         size = max(args->usize, sizeof(*uca));
  456         uca = malloc(size, M_LINUX, M_WAITOK | M_ZERO);
  457         error = copyin(args->uargs, uca, args->usize);
  458         if (error != 0)
  459                 goto out;
  460         error = linux_clone3_args_valid(uca);
  461         if (error != 0)
  462                 goto out;
  463         ca = malloc(sizeof(*ca), M_LINUX, M_WAITOK | M_ZERO);
  464         ca->flags = uca->flags;
  465         ca->child_tid = PTRIN(uca->child_tid);
  466         ca->parent_tid = PTRIN(uca->parent_tid);
  467         ca->exit_signal = uca->exit_signal;
  468         ca->stack = uca->stack + uca->stack_size;
  469         ca->stack_size = uca->stack_size;
  470         ca->tls = uca->tls;
  471 
  472         if ((ca->flags & LINUX_CLONE_THREAD) != 0)
  473                 error = linux_clone_thread(td, ca);
  474         else
  475                 error = linux_clone_proc(td, ca);
  476         free(ca, M_LINUX);
  477 out:
  478         free(uca, M_LINUX);
  479         return (error);
  480 }
  481 
  482 int
  483 linux_exit(struct thread *td, struct linux_exit_args *args)
  484 {
  485         struct linux_emuldata *em __diagused;
  486 
  487         em = em_find(td);
  488         KASSERT(em != NULL, ("exit: emuldata not found.\n"));
  489 
  490         LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
  491 
  492         linux_thread_detach(td);
  493 
  494         /*
  495          * XXX. When the last two threads of a process
  496          * exit via pthread_exit() try thr_exit() first.
  497          */
  498         kern_thr_exit(td);
  499         exit1(td, args->rval, 0);
  500                 /* NOTREACHED */
  501 }
  502 
  503 int
  504 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
  505 {
  506         struct linux_emuldata *em;
  507 
  508         em = em_find(td);
  509         KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
  510 
  511         em->child_clear_tid = args->tidptr;
  512 
  513         td->td_retval[0] = em->em_tid;
  514 
  515         LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
  516             em->em_tid, args->tidptr, td->td_retval[0]);
  517 
  518         return (0);
  519 }
  520 
  521 void
  522 linux_thread_detach(struct thread *td)
  523 {
  524         struct linux_emuldata *em;
  525         int *child_clear_tid;
  526         int error;
  527 
  528         em = em_find(td);
  529         KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
  530 
  531         LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
  532 
  533         release_futexes(td, em);
  534 
  535         child_clear_tid = em->child_clear_tid;
  536 
  537         if (child_clear_tid != NULL) {
  538                 LINUX_CTR2(thread_detach, "thread(%d) %p",
  539                     em->em_tid, child_clear_tid);
  540 
  541                 error = suword32(child_clear_tid, 0);
  542                 if (error != 0)
  543                         return;
  544 
  545                 error = futex_wake(td, child_clear_tid, 1, false);
  546                 /*
  547                  * this cannot happen at the moment and if this happens it
  548                  * probably means there is a user space bug
  549                  */
  550                 if (error != 0)
  551                         linux_msg(td, "futex stuff in thread_detach failed.");
  552         }
  553 
  554         /*
  555          * Do not rely on the robust list which is maintained by userspace,
  556          * cleanup remaining pi (if any) after release_futexes anyway.
  557          */
  558         umtx_thread_exit(td);
  559 }
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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
