subr_uio.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   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  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/9.1/sys/kern/subr_uio.c 233647 2012-03-29 04:54:34Z alc $");
   39 
   40 #include "opt_zero.h"
   41 
   42 #include <sys/param.h>
   43 #include <sys/systm.h>
   44 #include <sys/kernel.h>
   45 #include <sys/limits.h>
   46 #include <sys/lock.h>
   47 #include <sys/mman.h>
   48 #include <sys/mutex.h>
   49 #include <sys/proc.h>
   50 #include <sys/resourcevar.h>
   51 #include <sys/sched.h>
   52 #include <sys/sysctl.h>
   53 #include <sys/vnode.h>
   54 
   55 #include <vm/vm.h>
   56 #include <vm/vm_extern.h>
   57 #include <vm/vm_page.h>
   58 #include <vm/vm_map.h>
   59 #ifdef ZERO_COPY_SOCKETS
   60 #include <vm/vm_param.h>
   61 #include <vm/vm_object.h>
   62 #endif
   63 
   64 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
   65         "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
   66 
   67 static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
   68 
   69 #ifdef ZERO_COPY_SOCKETS
   70 /* Declared in uipc_socket.c */
   71 extern int so_zero_copy_receive;
   72 
   73 /*
   74  * Identify the physical page mapped at the given kernel virtual
   75  * address.  Insert this physical page into the given address space at
   76  * the given virtual address, replacing the physical page, if any,
   77  * that already exists there.
   78  */
   79 static int
   80 vm_pgmoveco(vm_map_t mapa, vm_offset_t kaddr, vm_offset_t uaddr)
   81 {
   82         vm_map_t map = mapa;
   83         vm_page_t kern_pg, user_pg;
   84         vm_object_t uobject;
   85         vm_map_entry_t entry;
   86         vm_pindex_t upindex;
   87         vm_prot_t prot;
   88         boolean_t wired;
   89 
   90         KASSERT((uaddr & PAGE_MASK) == 0,
   91             ("vm_pgmoveco: uaddr is not page aligned"));
   92 
   93         /*
   94          * Herein the physical page is validated and dirtied.  It is
   95          * unwired in sf_buf_mext().
   96          */
   97         kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr));
   98         kern_pg->valid = VM_PAGE_BITS_ALL;
   99         KASSERT(kern_pg->queue == PQ_NONE && kern_pg->wire_count == 1,
  100             ("vm_pgmoveco: kern_pg is not correctly wired"));
  101 
  102         if ((vm_map_lookup(&map, uaddr,
  103                            VM_PROT_WRITE, &entry, &uobject,
  104                            &upindex, &prot, &wired)) != KERN_SUCCESS) {
  105                 return(EFAULT);
  106         }
  107         VM_OBJECT_LOCK(uobject);
  108 retry:
  109         if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) {
  110                 if (vm_page_sleep_if_busy(user_pg, TRUE, "vm_pgmoveco"))
  111                         goto retry;
  112                 vm_page_lock(user_pg);
  113                 pmap_remove_all(user_pg);
  114                 vm_page_free(user_pg);
  115                 vm_page_unlock(user_pg);
  116         } else {
  117                 /*
  118                  * Even if a physical page does not exist in the
  119                  * object chain's first object, a physical page from a
  120                  * backing object may be mapped read only.
  121                  */
  122                 if (uobject->backing_object != NULL)
  123                         pmap_remove(map->pmap, uaddr, uaddr + PAGE_SIZE);
  124         }
  125         vm_page_insert(kern_pg, uobject, upindex);
  126         vm_page_dirty(kern_pg);
  127         VM_OBJECT_UNLOCK(uobject);
  128         vm_map_lookup_done(map, entry);
  129         return(KERN_SUCCESS);
  130 }
  131 #endif /* ZERO_COPY_SOCKETS */
  132 
  133 int
  134 copyin_nofault(const void *udaddr, void *kaddr, size_t len)
  135 {
  136         int error, save;
  137 
  138         save = vm_fault_disable_pagefaults();
  139         error = copyin(udaddr, kaddr, len);
  140         vm_fault_enable_pagefaults(save);
  141         return (error);
  142 }
  143 
  144 int
  145 copyout_nofault(const void *kaddr, void *udaddr, size_t len)
  146 {
  147         int error, save;
  148 
  149         save = vm_fault_disable_pagefaults();
  150         error = copyout(kaddr, udaddr, len);
  151         vm_fault_enable_pagefaults(save);
  152         return (error);
  153 }
  154 
  155 int
  156 uiomove(void *cp, int n, struct uio *uio)
  157 {
  158 
  159         return (uiomove_faultflag(cp, n, uio, 0));
  160 }
  161 
  162 int
  163 uiomove_nofault(void *cp, int n, struct uio *uio)
  164 {
  165 
  166         return (uiomove_faultflag(cp, n, uio, 1));
  167 }
  168 
  169 static int
  170 uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
  171 {
  172         struct thread *td;
  173         struct iovec *iov;
  174         size_t cnt;
  175         int error, newflags, save;
  176 
  177         td = curthread;
  178         error = 0;
  179 
  180         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  181             ("uiomove: mode"));
  182         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
  183             ("uiomove proc"));
  184         if (!nofault)
  185                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
  186                     "Calling uiomove()");
  187 
  188         /* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
  189         newflags = TDP_DEADLKTREAT;
  190         if (uio->uio_segflg == UIO_USERSPACE && nofault) {
  191                 /*
  192                  * Fail if a non-spurious page fault occurs.
  193                  */
  194                 newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
  195         }
  196         save = curthread_pflags_set(newflags);
  197 
  198         while (n > 0 && uio->uio_resid) {
  199                 iov = uio->uio_iov;
  200                 cnt = iov->iov_len;
  201                 if (cnt == 0) {
  202                         uio->uio_iov++;
  203                         uio->uio_iovcnt--;
  204                         continue;
  205                 }
  206                 if (cnt > n)
  207                         cnt = n;
  208 
  209                 switch (uio->uio_segflg) {
  210 
  211                 case UIO_USERSPACE:
  212                         maybe_yield();
  213                         if (uio->uio_rw == UIO_READ)
  214                                 error = copyout(cp, iov->iov_base, cnt);
  215                         else
  216                                 error = copyin(iov->iov_base, cp, cnt);
  217                         if (error)
  218                                 goto out;
  219                         break;
  220 
  221                 case UIO_SYSSPACE:
  222                         if (uio->uio_rw == UIO_READ)
  223                                 bcopy(cp, iov->iov_base, cnt);
  224                         else
  225                                 bcopy(iov->iov_base, cp, cnt);
  226                         break;
  227                 case UIO_NOCOPY:
  228                         break;
  229                 }
  230                 iov->iov_base = (char *)iov->iov_base + cnt;
  231                 iov->iov_len -= cnt;
  232                 uio->uio_resid -= cnt;
  233                 uio->uio_offset += cnt;
  234                 cp = (char *)cp + cnt;
  235                 n -= cnt;
  236         }
  237 out:
  238         curthread_pflags_restore(save);
  239         return (error);
  240 }
  241 
  242 /*
  243  * Wrapper for uiomove() that validates the arguments against a known-good
  244  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
  245  * is almost definitely a bad thing, so we catch that here as well.  We
  246  * return a runtime failure, but it might be desirable to generate a runtime
  247  * assertion failure instead.
  248  */
  249 int
  250 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
  251 {
  252         size_t offset, n;
  253 
  254         if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
  255             (offset = uio->uio_offset) != uio->uio_offset)
  256                 return (EINVAL);
  257         if (buflen <= 0 || offset >= buflen)
  258                 return (0);
  259         if ((n = buflen - offset) > IOSIZE_MAX)
  260                 return (EINVAL);
  261         return (uiomove((char *)buf + offset, n, uio));
  262 }
  263 
  264 #ifdef ZERO_COPY_SOCKETS
  265 /*
  266  * Experimental support for zero-copy I/O
  267  */
  268 static int
  269 userspaceco(void *cp, u_int cnt, struct uio *uio, int disposable)
  270 {
  271         struct iovec *iov;
  272         int error;
  273 
  274         iov = uio->uio_iov;
  275         if (uio->uio_rw == UIO_READ) {
  276                 if ((so_zero_copy_receive != 0)
  277                  && ((cnt & PAGE_MASK) == 0)
  278                  && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
  279                  && ((uio->uio_offset & PAGE_MASK) == 0)
  280                  && ((((intptr_t) cp) & PAGE_MASK) == 0)
  281                  && (disposable != 0)) {
  282                         /* SOCKET: use page-trading */
  283                         /*
  284                          * We only want to call vm_pgmoveco() on
  285                          * disposeable pages, since it gives the
  286                          * kernel page to the userland process.
  287                          */
  288                         error = vm_pgmoveco(&curproc->p_vmspace->vm_map,
  289                             (vm_offset_t)cp, (vm_offset_t)iov->iov_base);
  290 
  291                         /*
  292                          * If we get an error back, attempt
  293                          * to use copyout() instead.  The
  294                          * disposable page should be freed
  295                          * automatically if we weren't able to move
  296                          * it into userland.
  297                          */
  298                         if (error != 0)
  299                                 error = copyout(cp, iov->iov_base, cnt);
  300                 } else {
  301                         error = copyout(cp, iov->iov_base, cnt);
  302                 }
  303         } else {
  304                 error = copyin(iov->iov_base, cp, cnt);
  305         }
  306         return (error);
  307 }
  308 
  309 int
  310 uiomoveco(void *cp, int n, struct uio *uio, int disposable)
  311 {
  312         struct iovec *iov;
  313         u_int cnt;
  314         int error;
  315 
  316         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  317             ("uiomoveco: mode"));
  318         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  319             ("uiomoveco proc"));
  320 
  321         while (n > 0 && uio->uio_resid) {
  322                 iov = uio->uio_iov;
  323                 cnt = iov->iov_len;
  324                 if (cnt == 0) {
  325                         uio->uio_iov++;
  326                         uio->uio_iovcnt--;
  327                         continue;
  328                 }
  329                 if (cnt > n)
  330                         cnt = n;
  331 
  332                 switch (uio->uio_segflg) {
  333 
  334                 case UIO_USERSPACE:
  335                         maybe_yield();
  336                         error = userspaceco(cp, cnt, uio, disposable);
  337                         if (error)
  338                                 return (error);
  339                         break;
  340 
  341                 case UIO_SYSSPACE:
  342                         if (uio->uio_rw == UIO_READ)
  343                                 bcopy(cp, iov->iov_base, cnt);
  344                         else
  345                                 bcopy(iov->iov_base, cp, cnt);
  346                         break;
  347                 case UIO_NOCOPY:
  348                         break;
  349                 }
  350                 iov->iov_base = (char *)iov->iov_base + cnt;
  351                 iov->iov_len -= cnt;
  352                 uio->uio_resid -= cnt;
  353                 uio->uio_offset += cnt;
  354                 cp = (char *)cp + cnt;
  355                 n -= cnt;
  356         }
  357         return (0);
  358 }
  359 #endif /* ZERO_COPY_SOCKETS */
  360 
  361 /*
  362  * Give next character to user as result of read.
  363  */
  364 int
  365 ureadc(int c, struct uio *uio)
  366 {
  367         struct iovec *iov;
  368         char *iov_base;
  369 
  370         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
  371             "Calling ureadc()");
  372 
  373 again:
  374         if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
  375                 panic("ureadc");
  376         iov = uio->uio_iov;
  377         if (iov->iov_len == 0) {
  378                 uio->uio_iovcnt--;
  379                 uio->uio_iov++;
  380                 goto again;
  381         }
  382         switch (uio->uio_segflg) {
  383 
  384         case UIO_USERSPACE:
  385                 if (subyte(iov->iov_base, c) < 0)
  386                         return (EFAULT);
  387                 break;
  388 
  389         case UIO_SYSSPACE:
  390                 iov_base = iov->iov_base;
  391                 *iov_base = c;
  392                 iov->iov_base = iov_base;
  393                 break;
  394 
  395         case UIO_NOCOPY:
  396                 break;
  397         }
  398         iov->iov_base = (char *)iov->iov_base + 1;
  399         iov->iov_len--;
  400         uio->uio_resid--;
  401         uio->uio_offset++;
  402         return (0);
  403 }
  404 
  405 int
  406 copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
  407     int seg)
  408 {
  409         int error = 0;
  410 
  411         switch (seg) {
  412         case UIO_USERSPACE:
  413                 error = copyin(src, dst, len);
  414                 break;
  415         case UIO_SYSSPACE:
  416                 bcopy(src, dst, len);
  417                 break;
  418         default:
  419                 panic("copyinfrom: bad seg %d\n", seg);
  420         }
  421         return (error);
  422 }
  423 
  424 int
  425 copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
  426     size_t * __restrict copied, int seg)
  427 {
  428         int error = 0;
  429 
  430         switch (seg) {
  431         case UIO_USERSPACE:
  432                 error = copyinstr(src, dst, len, copied);
  433                 break;
  434         case UIO_SYSSPACE:
  435                 error = copystr(src, dst, len, copied);
  436                 break;
  437         default:
  438                 panic("copyinstrfrom: bad seg %d\n", seg);
  439         }
  440         return (error);
  441 }
  442 
  443 int
  444 copyiniov(struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
  445 {
  446         u_int iovlen;
  447 
  448         *iov = NULL;
  449         if (iovcnt > UIO_MAXIOV)
  450                 return (error);
  451         iovlen = iovcnt * sizeof (struct iovec);
  452         *iov = malloc(iovlen, M_IOV, M_WAITOK);
  453         error = copyin(iovp, *iov, iovlen);
  454         if (error) {
  455                 free(*iov, M_IOV);
  456                 *iov = NULL;
  457         }
  458         return (error);
  459 }
  460 
  461 int
  462 copyinuio(struct iovec *iovp, u_int iovcnt, struct uio **uiop)
  463 {
  464         struct iovec *iov;
  465         struct uio *uio;
  466         u_int iovlen;
  467         int error, i;
  468 
  469         *uiop = NULL;
  470         if (iovcnt > UIO_MAXIOV)
  471                 return (EINVAL);
  472         iovlen = iovcnt * sizeof (struct iovec);
  473         uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
  474         iov = (struct iovec *)(uio + 1);
  475         error = copyin(iovp, iov, iovlen);
  476         if (error) {
  477                 free(uio, M_IOV);
  478                 return (error);
  479         }
  480         uio->uio_iov = iov;
  481         uio->uio_iovcnt = iovcnt;
  482         uio->uio_segflg = UIO_USERSPACE;
  483         uio->uio_offset = -1;
  484         uio->uio_resid = 0;
  485         for (i = 0; i < iovcnt; i++) {
  486                 if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
  487                         free(uio, M_IOV);
  488                         return (EINVAL);
  489                 }
  490                 uio->uio_resid += iov->iov_len;
  491                 iov++;
  492         }
  493         *uiop = uio;
  494         return (0);
  495 }
  496 
  497 struct uio *
  498 cloneuio(struct uio *uiop)
  499 {
  500         struct uio *uio;
  501         int iovlen;
  502 
  503         iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
  504         uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
  505         *uio = *uiop;
  506         uio->uio_iov = (struct iovec *)(uio + 1);
  507         bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
  508         return (uio);
  509 }
  510 
  511 /*
  512  * Map some anonymous memory in user space of size sz, rounded up to the page
  513  * boundary.
  514  */
  515 int
  516 copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
  517 {
  518         struct vmspace *vms;
  519         int error;
  520         vm_size_t size;
  521 
  522         vms = td->td_proc->p_vmspace;
  523 
  524         /*
  525          * Map somewhere after heap in process memory.
  526          */
  527         PROC_LOCK(td->td_proc);
  528         *addr = round_page((vm_offset_t)vms->vm_daddr +
  529             lim_max(td->td_proc, RLIMIT_DATA));
  530         PROC_UNLOCK(td->td_proc);
  531 
  532         /* round size up to page boundry */
  533         size = (vm_size_t)round_page(sz);
  534 
  535         error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE,
  536             VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
  537 
  538         return (error);
  539 }
  540 
  541 /*
  542  * Unmap memory in user space.
  543  */
  544 int
  545 copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
  546 {
  547         vm_map_t map;
  548         vm_size_t size;
  549 
  550         if (sz == 0)
  551                 return (0);
  552 
  553         map = &td->td_proc->p_vmspace->vm_map;
  554         size = (vm_size_t)round_page(sz);
  555 
  556         if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
  557                 return (EINVAL);
  558 
  559         return (0);
  560 }
Cache object: 89aa6c06b8b23a9388a8e237faa04767
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_uio.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_uio.c
