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  * Copyright (c) 2014 The FreeBSD Foundation
   11  *
   12  * Portions of this software were developed by Konstantin Belousov
   13  * under sponsorship from the FreeBSD Foundation.
   14  *
   15  * Redistribution and use in source and binary forms, with or without
   16  * modification, are permitted provided that the following conditions
   17  * are met:
   18  * 1. Redistributions of source code must retain the above copyright
   19  *    notice, this list of conditions and the following disclaimer.
   20  * 2. Redistributions in binary form must reproduce the above copyright
   21  *    notice, this list of conditions and the following disclaimer in the
   22  *    documentation and/or other materials provided with the distribution.
   23  * 4. Neither the name of the University nor the names of its contributors
   24  *    may be used to endorse or promote products derived from this software
   25  *    without specific prior written permission.
   26  *
   27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   37  * SUCH DAMAGE.
   38  *
   39  *      @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
   40  */
   41 
   42 #include <sys/cdefs.h>
   43 __FBSDID("$FreeBSD: releng/10.2/sys/kern/subr_uio.c 274648 2014-11-18 12:53:32Z kib $");
   44 
   45 #include <sys/param.h>
   46 #include <sys/systm.h>
   47 #include <sys/kernel.h>
   48 #include <sys/limits.h>
   49 #include <sys/lock.h>
   50 #include <sys/mman.h>
   51 #include <sys/proc.h>
   52 #include <sys/resourcevar.h>
   53 #include <sys/rwlock.h>
   54 #include <sys/sched.h>
   55 #include <sys/sysctl.h>
   56 #include <sys/vnode.h>
   57 
   58 #include <vm/vm.h>
   59 #include <vm/vm_param.h>
   60 #include <vm/vm_extern.h>
   61 #include <vm/vm_page.h>
   62 #include <vm/vm_pageout.h>
   63 #include <vm/vm_map.h>
   64 
   65 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, UIO_MAXIOV,
   66         "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
   67 
   68 static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
   69 
   70 int
   71 copyin_nofault(const void *udaddr, void *kaddr, size_t len)
   72 {
   73         int error, save;
   74 
   75         save = vm_fault_disable_pagefaults();
   76         error = copyin(udaddr, kaddr, len);
   77         vm_fault_enable_pagefaults(save);
   78         return (error);
   79 }
   80 
   81 int
   82 copyout_nofault(const void *kaddr, void *udaddr, size_t len)
   83 {
   84         int error, save;
   85 
   86         save = vm_fault_disable_pagefaults();
   87         error = copyout(kaddr, udaddr, len);
   88         vm_fault_enable_pagefaults(save);
   89         return (error);
   90 }
   91 
   92 #define PHYS_PAGE_COUNT(len)    (howmany(len, PAGE_SIZE) + 1)
   93 
   94 int
   95 physcopyin(void *src, vm_paddr_t dst, size_t len)
   96 {
   97         vm_page_t m[PHYS_PAGE_COUNT(len)];
   98         struct iovec iov[1];
   99         struct uio uio;
  100         int i;
  101 
  102         iov[0].iov_base = src;
  103         iov[0].iov_len = len;
  104         uio.uio_iov = iov;
  105         uio.uio_iovcnt = 1;
  106         uio.uio_offset = 0;
  107         uio.uio_resid = len;
  108         uio.uio_segflg = UIO_SYSSPACE;
  109         uio.uio_rw = UIO_WRITE;
  110         for (i = 0; i < PHYS_PAGE_COUNT(len); i++, dst += PAGE_SIZE)
  111                 m[i] = PHYS_TO_VM_PAGE(dst);
  112         return (uiomove_fromphys(m, dst & PAGE_MASK, len, &uio));
  113 }
  114 
  115 int
  116 physcopyout(vm_paddr_t src, void *dst, size_t len)
  117 {
  118         vm_page_t m[PHYS_PAGE_COUNT(len)];
  119         struct iovec iov[1];
  120         struct uio uio;
  121         int i;
  122 
  123         iov[0].iov_base = dst;
  124         iov[0].iov_len = len;
  125         uio.uio_iov = iov;
  126         uio.uio_iovcnt = 1;
  127         uio.uio_offset = 0;
  128         uio.uio_resid = len;
  129         uio.uio_segflg = UIO_SYSSPACE;
  130         uio.uio_rw = UIO_READ;
  131         for (i = 0; i < PHYS_PAGE_COUNT(len); i++, src += PAGE_SIZE)
  132                 m[i] = PHYS_TO_VM_PAGE(src);
  133         return (uiomove_fromphys(m, src & PAGE_MASK, len, &uio));
  134 }
  135 
  136 #undef PHYS_PAGE_COUNT
  137 
  138 int
  139 uiomove(void *cp, int n, struct uio *uio)
  140 {
  141 
  142         return (uiomove_faultflag(cp, n, uio, 0));
  143 }
  144 
  145 int
  146 uiomove_nofault(void *cp, int n, struct uio *uio)
  147 {
  148 
  149         return (uiomove_faultflag(cp, n, uio, 1));
  150 }
  151 
  152 static int
  153 uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
  154 {
  155         struct thread *td;
  156         struct iovec *iov;
  157         size_t cnt;
  158         int error, newflags, save;
  159 
  160         td = curthread;
  161         error = 0;
  162 
  163         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  164             ("uiomove: mode"));
  165         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
  166             ("uiomove proc"));
  167         if (!nofault)
  168                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
  169                     "Calling uiomove()");
  170 
  171         /* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
  172         newflags = TDP_DEADLKTREAT;
  173         if (uio->uio_segflg == UIO_USERSPACE && nofault) {
  174                 /*
  175                  * Fail if a non-spurious page fault occurs.
  176                  */
  177                 newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
  178         }
  179         save = curthread_pflags_set(newflags);
  180 
  181         while (n > 0 && uio->uio_resid) {
  182                 iov = uio->uio_iov;
  183                 cnt = iov->iov_len;
  184                 if (cnt == 0) {
  185                         uio->uio_iov++;
  186                         uio->uio_iovcnt--;
  187                         continue;
  188                 }
  189                 if (cnt > n)
  190                         cnt = n;
  191 
  192                 switch (uio->uio_segflg) {
  193 
  194                 case UIO_USERSPACE:
  195                         maybe_yield();
  196                         if (uio->uio_rw == UIO_READ)
  197                                 error = copyout(cp, iov->iov_base, cnt);
  198                         else
  199                                 error = copyin(iov->iov_base, cp, cnt);
  200                         if (error)
  201                                 goto out;
  202                         break;
  203 
  204                 case UIO_SYSSPACE:
  205                         if (uio->uio_rw == UIO_READ)
  206                                 bcopy(cp, iov->iov_base, cnt);
  207                         else
  208                                 bcopy(iov->iov_base, cp, cnt);
  209                         break;
  210                 case UIO_NOCOPY:
  211                         break;
  212                 }
  213                 iov->iov_base = (char *)iov->iov_base + cnt;
  214                 iov->iov_len -= cnt;
  215                 uio->uio_resid -= cnt;
  216                 uio->uio_offset += cnt;
  217                 cp = (char *)cp + cnt;
  218                 n -= cnt;
  219         }
  220 out:
  221         curthread_pflags_restore(save);
  222         return (error);
  223 }
  224 
  225 /*
  226  * Wrapper for uiomove() that validates the arguments against a known-good
  227  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
  228  * is almost definitely a bad thing, so we catch that here as well.  We
  229  * return a runtime failure, but it might be desirable to generate a runtime
  230  * assertion failure instead.
  231  */
  232 int
  233 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
  234 {
  235         size_t offset, n;
  236 
  237         if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
  238             (offset = uio->uio_offset) != uio->uio_offset)
  239                 return (EINVAL);
  240         if (buflen <= 0 || offset >= buflen)
  241                 return (0);
  242         if ((n = buflen - offset) > IOSIZE_MAX)
  243                 return (EINVAL);
  244         return (uiomove((char *)buf + offset, n, uio));
  245 }
  246 
  247 /*
  248  * Give next character to user as result of read.
  249  */
  250 int
  251 ureadc(int c, struct uio *uio)
  252 {
  253         struct iovec *iov;
  254         char *iov_base;
  255 
  256         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
  257             "Calling ureadc()");
  258 
  259 again:
  260         if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
  261                 panic("ureadc");
  262         iov = uio->uio_iov;
  263         if (iov->iov_len == 0) {
  264                 uio->uio_iovcnt--;
  265                 uio->uio_iov++;
  266                 goto again;
  267         }
  268         switch (uio->uio_segflg) {
  269 
  270         case UIO_USERSPACE:
  271                 if (subyte(iov->iov_base, c) < 0)
  272                         return (EFAULT);
  273                 break;
  274 
  275         case UIO_SYSSPACE:
  276                 iov_base = iov->iov_base;
  277                 *iov_base = c;
  278                 break;
  279 
  280         case UIO_NOCOPY:
  281                 break;
  282         }
  283         iov->iov_base = (char *)iov->iov_base + 1;
  284         iov->iov_len--;
  285         uio->uio_resid--;
  286         uio->uio_offset++;
  287         return (0);
  288 }
  289 
  290 int
  291 copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
  292     int seg)
  293 {
  294         int error = 0;
  295 
  296         switch (seg) {
  297         case UIO_USERSPACE:
  298                 error = copyin(src, dst, len);
  299                 break;
  300         case UIO_SYSSPACE:
  301                 bcopy(src, dst, len);
  302                 break;
  303         default:
  304                 panic("copyinfrom: bad seg %d\n", seg);
  305         }
  306         return (error);
  307 }
  308 
  309 int
  310 copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
  311     size_t * __restrict copied, int seg)
  312 {
  313         int error = 0;
  314 
  315         switch (seg) {
  316         case UIO_USERSPACE:
  317                 error = copyinstr(src, dst, len, copied);
  318                 break;
  319         case UIO_SYSSPACE:
  320                 error = copystr(src, dst, len, copied);
  321                 break;
  322         default:
  323                 panic("copyinstrfrom: bad seg %d\n", seg);
  324         }
  325         return (error);
  326 }
  327 
  328 int
  329 copyiniov(const struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
  330 {
  331         u_int iovlen;
  332 
  333         *iov = NULL;
  334         if (iovcnt > UIO_MAXIOV)
  335                 return (error);
  336         iovlen = iovcnt * sizeof (struct iovec);
  337         *iov = malloc(iovlen, M_IOV, M_WAITOK);
  338         error = copyin(iovp, *iov, iovlen);
  339         if (error) {
  340                 free(*iov, M_IOV);
  341                 *iov = NULL;
  342         }
  343         return (error);
  344 }
  345 
  346 int
  347 copyinuio(const struct iovec *iovp, u_int iovcnt, struct uio **uiop)
  348 {
  349         struct iovec *iov;
  350         struct uio *uio;
  351         u_int iovlen;
  352         int error, i;
  353 
  354         *uiop = NULL;
  355         if (iovcnt > UIO_MAXIOV)
  356                 return (EINVAL);
  357         iovlen = iovcnt * sizeof (struct iovec);
  358         uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
  359         iov = (struct iovec *)(uio + 1);
  360         error = copyin(iovp, iov, iovlen);
  361         if (error) {
  362                 free(uio, M_IOV);
  363                 return (error);
  364         }
  365         uio->uio_iov = iov;
  366         uio->uio_iovcnt = iovcnt;
  367         uio->uio_segflg = UIO_USERSPACE;
  368         uio->uio_offset = -1;
  369         uio->uio_resid = 0;
  370         for (i = 0; i < iovcnt; i++) {
  371                 if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
  372                         free(uio, M_IOV);
  373                         return (EINVAL);
  374                 }
  375                 uio->uio_resid += iov->iov_len;
  376                 iov++;
  377         }
  378         *uiop = uio;
  379         return (0);
  380 }
  381 
  382 struct uio *
  383 cloneuio(struct uio *uiop)
  384 {
  385         struct uio *uio;
  386         int iovlen;
  387 
  388         iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
  389         uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
  390         *uio = *uiop;
  391         uio->uio_iov = (struct iovec *)(uio + 1);
  392         bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
  393         return (uio);
  394 }
  395 
  396 /*
  397  * Map some anonymous memory in user space of size sz, rounded up to the page
  398  * boundary.
  399  */
  400 int
  401 copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
  402 {
  403         struct vmspace *vms;
  404         int error;
  405         vm_size_t size;
  406 
  407         vms = td->td_proc->p_vmspace;
  408 
  409         /*
  410          * Map somewhere after heap in process memory.
  411          */
  412         PROC_LOCK(td->td_proc);
  413         *addr = round_page((vm_offset_t)vms->vm_daddr +
  414             lim_max(td->td_proc, RLIMIT_DATA));
  415         PROC_UNLOCK(td->td_proc);
  416 
  417         /* round size up to page boundry */
  418         size = (vm_size_t)round_page(sz);
  419 
  420         error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE,
  421             VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
  422 
  423         return (error);
  424 }
  425 
  426 /*
  427  * Unmap memory in user space.
  428  */
  429 int
  430 copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
  431 {
  432         vm_map_t map;
  433         vm_size_t size;
  434 
  435         if (sz == 0)
  436                 return (0);
  437 
  438         map = &td->td_proc->p_vmspace->vm_map;
  439         size = (vm_size_t)round_page(sz);
  440 
  441         if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
  442                 return (EINVAL);
  443 
  444         return (0);
  445 }
  446 
  447 #ifdef NO_FUEWORD
  448 /*
  449  * XXXKIB The temporal implementation of fue*() functions which do not
  450  * handle usermode -1 properly, mixing it with the fault code.  Keep
  451  * this until MD code is written.  Currently sparc64, mips and arm do
  452  * not have proper implementation.
  453  */
  454 
  455 int
  456 fueword(volatile const void *base, long *val)
  457 {
  458         long res;
  459 
  460         res = fuword(base);
  461         if (res == -1)
  462                 return (-1);
  463         *val = res;
  464         return (0);
  465 }
  466 
  467 int
  468 fueword32(volatile const void *base, int32_t *val)
  469 {
  470         int32_t res;
  471 
  472         res = fuword32(base);
  473         if (res == -1)
  474                 return (-1);
  475         *val = res;
  476         return (0);
  477 }
  478 
  479 #ifdef _LP64
  480 int
  481 fueword64(volatile const void *base, int64_t *val)
  482 {
  483         int32_t res;
  484 
  485         res = fuword64(base);
  486         if (res == -1)
  487                 return (-1);
  488         *val = res;
  489         return (0);
  490 }
  491 #endif
  492 
  493 int
  494 casueword32(volatile uint32_t *base, uint32_t oldval, uint32_t *oldvalp,
  495     uint32_t newval)
  496 {
  497         int32_t ov;
  498 
  499         ov = casuword32(base, oldval, newval);
  500         if (ov == -1)
  501                 return (-1);
  502         *oldvalp = ov;
  503         return (0);
  504 }
  505 
  506 int
  507 casueword(volatile u_long *p, u_long oldval, u_long *oldvalp, u_long newval)
  508 {
  509         u_long ov;
  510 
  511         ov = casuword(p, oldval, newval);
  512         if (ov == -1)
  513                 return (-1);
  514         *oldvalp = ov;
  515         return (0);
  516 }
  517 #else /* NO_FUEWORD */
  518 int32_t
  519 fuword32(volatile const void *addr)
  520 {
  521         int rv;
  522         int32_t val;
  523 
  524         rv = fueword32(addr, &val);
  525         return (rv == -1 ? -1 : val);
  526 }
  527 
  528 #ifdef _LP64
  529 int64_t
  530 fuword64(volatile const void *addr)
  531 {
  532         int rv;
  533         int64_t val;
  534 
  535         rv = fueword64(addr, &val);
  536         return (rv == -1 ? -1 : val);
  537 }
  538 #endif /* _LP64 */
  539 
  540 long
  541 fuword(volatile const void *addr)
  542 {
  543         long val;
  544         int rv;
  545 
  546         rv = fueword(addr, &val);
  547         return (rv == -1 ? -1 : val);
  548 }
  549 
  550 uint32_t
  551 casuword32(volatile uint32_t *addr, uint32_t old, uint32_t new)
  552 {
  553         int rv;
  554         uint32_t val;
  555 
  556         rv = casueword32(addr, old, &val, new);
  557         return (rv == -1 ? -1 : val);
  558 }
  559 
  560 u_long
  561 casuword(volatile u_long *addr, u_long old, u_long new)
  562 {
  563         int rv;
  564         u_long val;
  565 
  566         rv = casueword(addr, old, &val, new);
  567         return (rv == -1 ? -1 : val);
  568 }
  569 
  570 #endif /* NO_FUEWORD */
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_uio.c

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