Current Path : /sys/kern/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //sys/kern/subr_uio.c |
/*- * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94 */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/sys/kern/subr_uio.c 233647 2012-03-29 04:54:34Z alc $"); #include "opt_zero.h" #include <sys/param.h> #include <sys/systm.h> #include <sys/kernel.h> #include <sys/limits.h> #include <sys/lock.h> #include <sys/mman.h> #include <sys/mutex.h> #include <sys/proc.h> #include <sys/resourcevar.h> #include <sys/sched.h> #include <sys/sysctl.h> #include <sys/vnode.h> #include <vm/vm.h> #include <vm/vm_extern.h> #include <vm/vm_page.h> #include <vm/vm_map.h> #ifdef ZERO_COPY_SOCKETS #include <vm/vm_param.h> #include <vm/vm_object.h> #endif SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV, "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)"); static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault); #ifdef ZERO_COPY_SOCKETS /* Declared in uipc_socket.c */ extern int so_zero_copy_receive; /* * Identify the physical page mapped at the given kernel virtual * address. Insert this physical page into the given address space at * the given virtual address, replacing the physical page, if any, * that already exists there. */ static int vm_pgmoveco(vm_map_t mapa, vm_offset_t kaddr, vm_offset_t uaddr) { vm_map_t map = mapa; vm_page_t kern_pg, user_pg; vm_object_t uobject; vm_map_entry_t entry; vm_pindex_t upindex; vm_prot_t prot; boolean_t wired; KASSERT((uaddr & PAGE_MASK) == 0, ("vm_pgmoveco: uaddr is not page aligned")); /* * Herein the physical page is validated and dirtied. It is * unwired in sf_buf_mext(). */ kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr)); kern_pg->valid = VM_PAGE_BITS_ALL; KASSERT(kern_pg->queue == PQ_NONE && kern_pg->wire_count == 1, ("vm_pgmoveco: kern_pg is not correctly wired")); if ((vm_map_lookup(&map, uaddr, VM_PROT_WRITE, &entry, &uobject, &upindex, &prot, &wired)) != KERN_SUCCESS) { return(EFAULT); } VM_OBJECT_LOCK(uobject); retry: if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) { if (vm_page_sleep_if_busy(user_pg, TRUE, "vm_pgmoveco")) goto retry; vm_page_lock(user_pg); pmap_remove_all(user_pg); vm_page_free(user_pg); vm_page_unlock(user_pg); } else { /* * Even if a physical page does not exist in the * object chain's first object, a physical page from a * backing object may be mapped read only. */ if (uobject->backing_object != NULL) pmap_remove(map->pmap, uaddr, uaddr + PAGE_SIZE); } vm_page_insert(kern_pg, uobject, upindex); vm_page_dirty(kern_pg); VM_OBJECT_UNLOCK(uobject); vm_map_lookup_done(map, entry); return(KERN_SUCCESS); } #endif /* ZERO_COPY_SOCKETS */ int copyin_nofault(const void *udaddr, void *kaddr, size_t len) { int error, save; save = vm_fault_disable_pagefaults(); error = copyin(udaddr, kaddr, len); vm_fault_enable_pagefaults(save); return (error); } int copyout_nofault(const void *kaddr, void *udaddr, size_t len) { int error, save; save = vm_fault_disable_pagefaults(); error = copyout(kaddr, udaddr, len); vm_fault_enable_pagefaults(save); return (error); } int uiomove(void *cp, int n, struct uio *uio) { return (uiomove_faultflag(cp, n, uio, 0)); } int uiomove_nofault(void *cp, int n, struct uio *uio) { return (uiomove_faultflag(cp, n, uio, 1)); } static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault) { struct thread *td; struct iovec *iov; size_t cnt; int error, newflags, save; td = curthread; error = 0; KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE, ("uiomove: mode")); KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td, ("uiomove proc")); if (!nofault) WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "Calling uiomove()"); /* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */ newflags = TDP_DEADLKTREAT; if (uio->uio_segflg == UIO_USERSPACE && nofault) { /* * Fail if a non-spurious page fault occurs. */ newflags |= TDP_NOFAULTING | TDP_RESETSPUR; } save = curthread_pflags_set(newflags); while (n > 0 && uio->uio_resid) { iov = uio->uio_iov; cnt = iov->iov_len; if (cnt == 0) { uio->uio_iov++; uio->uio_iovcnt--; continue; } if (cnt > n) cnt = n; switch (uio->uio_segflg) { case UIO_USERSPACE: maybe_yield(); if (uio->uio_rw == UIO_READ) error = copyout(cp, iov->iov_base, cnt); else error = copyin(iov->iov_base, cp, cnt); if (error) goto out; break; case UIO_SYSSPACE: if (uio->uio_rw == UIO_READ) bcopy(cp, iov->iov_base, cnt); else bcopy(iov->iov_base, cp, cnt); break; case UIO_NOCOPY: break; } iov->iov_base = (char *)iov->iov_base + cnt; iov->iov_len -= cnt; uio->uio_resid -= cnt; uio->uio_offset += cnt; cp = (char *)cp + cnt; n -= cnt; } out: curthread_pflags_restore(save); return (error); } /* * Wrapper for uiomove() that validates the arguments against a known-good * kernel buffer. Currently, uiomove accepts a signed (n) argument, which * is almost definitely a bad thing, so we catch that here as well. We * return a runtime failure, but it might be desirable to generate a runtime * assertion failure instead. */ int uiomove_frombuf(void *buf, int buflen, struct uio *uio) { size_t offset, n; if (uio->uio_offset < 0 || uio->uio_resid < 0 || (offset = uio->uio_offset) != uio->uio_offset) return (EINVAL); if (buflen <= 0 || offset >= buflen) return (0); if ((n = buflen - offset) > IOSIZE_MAX) return (EINVAL); return (uiomove((char *)buf + offset, n, uio)); } #ifdef ZERO_COPY_SOCKETS /* * Experimental support for zero-copy I/O */ static int userspaceco(void *cp, u_int cnt, struct uio *uio, int disposable) { struct iovec *iov; int error; iov = uio->uio_iov; if (uio->uio_rw == UIO_READ) { if ((so_zero_copy_receive != 0) && ((cnt & PAGE_MASK) == 0) && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0) && ((uio->uio_offset & PAGE_MASK) == 0) && ((((intptr_t) cp) & PAGE_MASK) == 0) && (disposable != 0)) { /* SOCKET: use page-trading */ /* * We only want to call vm_pgmoveco() on * disposeable pages, since it gives the * kernel page to the userland process. */ error = vm_pgmoveco(&curproc->p_vmspace->vm_map, (vm_offset_t)cp, (vm_offset_t)iov->iov_base); /* * If we get an error back, attempt * to use copyout() instead. The * disposable page should be freed * automatically if we weren't able to move * it into userland. */ if (error != 0) error = copyout(cp, iov->iov_base, cnt); } else { error = copyout(cp, iov->iov_base, cnt); } } else { error = copyin(iov->iov_base, cp, cnt); } return (error); } int uiomoveco(void *cp, int n, struct uio *uio, int disposable) { struct iovec *iov; u_int cnt; int error; KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE, ("uiomoveco: mode")); KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread, ("uiomoveco proc")); while (n > 0 && uio->uio_resid) { iov = uio->uio_iov; cnt = iov->iov_len; if (cnt == 0) { uio->uio_iov++; uio->uio_iovcnt--; continue; } if (cnt > n) cnt = n; switch (uio->uio_segflg) { case UIO_USERSPACE: maybe_yield(); error = userspaceco(cp, cnt, uio, disposable); if (error) return (error); break; case UIO_SYSSPACE: if (uio->uio_rw == UIO_READ) bcopy(cp, iov->iov_base, cnt); else bcopy(iov->iov_base, cp, cnt); break; case UIO_NOCOPY: break; } iov->iov_base = (char *)iov->iov_base + cnt; iov->iov_len -= cnt; uio->uio_resid -= cnt; uio->uio_offset += cnt; cp = (char *)cp + cnt; n -= cnt; } return (0); } #endif /* ZERO_COPY_SOCKETS */ /* * Give next character to user as result of read. */ int ureadc(int c, struct uio *uio) { struct iovec *iov; char *iov_base; WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "Calling ureadc()"); again: if (uio->uio_iovcnt == 0 || uio->uio_resid == 0) panic("ureadc"); iov = uio->uio_iov; if (iov->iov_len == 0) { uio->uio_iovcnt--; uio->uio_iov++; goto again; } switch (uio->uio_segflg) { case UIO_USERSPACE: if (subyte(iov->iov_base, c) < 0) return (EFAULT); break; case UIO_SYSSPACE: iov_base = iov->iov_base; *iov_base = c; iov->iov_base = iov_base; break; case UIO_NOCOPY: break; } iov->iov_base = (char *)iov->iov_base + 1; iov->iov_len--; uio->uio_resid--; uio->uio_offset++; return (0); } int copyinfrom(const void * __restrict src, void * __restrict dst, size_t len, int seg) { int error = 0; switch (seg) { case UIO_USERSPACE: error = copyin(src, dst, len); break; case UIO_SYSSPACE: bcopy(src, dst, len); break; default: panic("copyinfrom: bad seg %d\n", seg); } return (error); } int copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len, size_t * __restrict copied, int seg) { int error = 0; switch (seg) { case UIO_USERSPACE: error = copyinstr(src, dst, len, copied); break; case UIO_SYSSPACE: error = copystr(src, dst, len, copied); break; default: panic("copyinstrfrom: bad seg %d\n", seg); } return (error); } int copyiniov(struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error) { u_int iovlen; *iov = NULL; if (iovcnt > UIO_MAXIOV) return (error); iovlen = iovcnt * sizeof (struct iovec); *iov = malloc(iovlen, M_IOV, M_WAITOK); error = copyin(iovp, *iov, iovlen); if (error) { free(*iov, M_IOV); *iov = NULL; } return (error); } int copyinuio(struct iovec *iovp, u_int iovcnt, struct uio **uiop) { struct iovec *iov; struct uio *uio; u_int iovlen; int error, i; *uiop = NULL; if (iovcnt > UIO_MAXIOV) return (EINVAL); iovlen = iovcnt * sizeof (struct iovec); uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK); iov = (struct iovec *)(uio + 1); error = copyin(iovp, iov, iovlen); if (error) { free(uio, M_IOV); return (error); } uio->uio_iov = iov; uio->uio_iovcnt = iovcnt; uio->uio_segflg = UIO_USERSPACE; uio->uio_offset = -1; uio->uio_resid = 0; for (i = 0; i < iovcnt; i++) { if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) { free(uio, M_IOV); return (EINVAL); } uio->uio_resid += iov->iov_len; iov++; } *uiop = uio; return (0); } struct uio * cloneuio(struct uio *uiop) { struct uio *uio; int iovlen; iovlen = uiop->uio_iovcnt * sizeof (struct iovec); uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK); *uio = *uiop; uio->uio_iov = (struct iovec *)(uio + 1); bcopy(uiop->uio_iov, uio->uio_iov, iovlen); return (uio); } /* * Map some anonymous memory in user space of size sz, rounded up to the page * boundary. */ int copyout_map(struct thread *td, vm_offset_t *addr, size_t sz) { struct vmspace *vms; int error; vm_size_t size; vms = td->td_proc->p_vmspace; /* * Map somewhere after heap in process memory. */ PROC_LOCK(td->td_proc); *addr = round_page((vm_offset_t)vms->vm_daddr + lim_max(td->td_proc, RLIMIT_DATA)); PROC_UNLOCK(td->td_proc); /* round size up to page boundry */ size = (vm_size_t)round_page(sz); error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE, VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0); return (error); } /* * Unmap memory in user space. */ int copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz) { vm_map_t map; vm_size_t size; if (sz == 0) return (0); map = &td->td_proc->p_vmspace->vm_map; size = (vm_size_t)round_page(sz); if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS) return (EINVAL); return (0); }