/* * 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. * 3. 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 * $FreeBSD: src/sys/kern/kern_subr.c,v 1.31.2.2 2002/04/21 08:09:37 bde Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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)"); int copyin_nofault(const void *udaddr, void *kaddr, size_t len) { thread_t td = curthread; int error; atomic_set_int(&td->td_flags, TDF_NOFAULT); error = copyin(udaddr, kaddr, len); atomic_clear_int(&td->td_flags, TDF_NOFAULT); return error; } int copyout_nofault(const void *kaddr, void *udaddr, size_t len) { thread_t td = curthread; int error; atomic_set_int(&td->td_flags, TDF_NOFAULT); error = copyout(kaddr, udaddr, len); atomic_clear_int(&td->td_flags, TDF_NOFAULT); return error; } /* * UIO_READ: copy the kernelspace cp to the user or kernelspace UIO * UIO_WRITE: copy the user or kernelspace UIO to the kernelspace cp * * For userspace UIO's, uio_td must be the current thread. * * The syscall interface is responsible for limiting the length to * ssize_t for things like read() or write() which return the bytes * read or written as ssize_t. These functions work with unsigned * lengths. */ int uiomove(caddr_t cp, size_t n, struct uio *uio) { thread_t td = curthread; struct iovec *iov; size_t cnt; size_t tot; int error = 0; int save = 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")); crit_enter(); save = td->td_flags & TDF_DEADLKTREAT; td->td_flags |= TDF_DEADLKTREAT; crit_exit(); tot = 0; 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; tot += cnt; switch (uio->uio_segflg) { case UIO_USERSPACE: if (tot > 1024*1024) lwkt_user_yield(); if (uio->uio_rw == UIO_READ) error = copyout(cp, iov->iov_base, cnt); else error = copyin(iov->iov_base, cp, cnt); 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; } if (error) break; iov->iov_base = (char *)iov->iov_base + cnt; iov->iov_len -= cnt; uio->uio_resid -= cnt; uio->uio_offset += cnt; cp += cnt; n -= cnt; } crit_enter(); td->td_flags = (td->td_flags & ~TDF_DEADLKTREAT) | save; crit_exit(); return (error); } /* * This is the same as uiomove() except (cp, n) is within the bounds of * the passed, locked buffer. Under certain circumstances a VM fault * occuring with a locked buffer held can result in a deadlock or an * attempt to recursively lock the buffer. * * This procedure deals with these cases. * * If the buffer represents a regular file, is B_CACHE, but the last VM page * is not fully valid we fix-up the last VM page. This should handle the * recursive lock issue. * * Deadlocks are another issue. We are holding the vp and the bp locked * and could deadlock against a different vp and/or bp if another thread is * trying to access us while we accessing it. The only solution here is * to release the bp and vnode lock and do the uio to/from a system buffer, * then regain the locks and copyback (if applicable). XXX TODO. */ int uiomovebp(struct buf *bp, caddr_t cp, size_t n, struct uio *uio) { int count; vm_page_t m; if (bp->b_vp && bp->b_vp->v_type == VREG && (bp->b_flags & B_CACHE) && (count = bp->b_xio.xio_npages) != 0 && (m = bp->b_xio.xio_pages[count-1])->valid != VM_PAGE_BITS_ALL) { vm_page_zero_invalid(m, TRUE); } return (uiomove(cp, n, uio)); } /* * uiomove() but fail for non-trivial VM faults, even if the VM fault is * valid. Returns EFAULT if a VM fault occurred via the copyin/copyout * onfault code. * * This allows callers to hold e.g. a busy VM page, or a busy VM object, * or a locked vnode through the call and then fall-back to safer code * if we fail. */ int uiomove_nofault(caddr_t cp, size_t n, struct uio *uio) { thread_t td = curthread; int error; atomic_set_int(&td->td_flags, TDF_NOFAULT); error = uiomove(cp, n, uio); atomic_clear_int(&td->td_flags, TDF_NOFAULT); return error; } /* * Like uiomove() but copies zero-fill. Only allowed for UIO_READ, * for obvious reasons. */ int uiomovez(size_t n, struct uio *uio) { struct iovec *iov; size_t cnt; int error = 0; KASSERT(uio->uio_rw == UIO_READ, ("uiomovez: mode")); KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread, ("uiomove 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: error = copyout(ZeroPage, iov->iov_base, cnt); break; case UIO_SYSSPACE: bzero(iov->iov_base, cnt); break; case UIO_NOCOPY: break; } if (error) break; iov->iov_base = (char *)iov->iov_base + cnt; iov->iov_len -= cnt; uio->uio_resid -= cnt; uio->uio_offset += cnt; n -= cnt; } return (error); } /* * Wrapper for uiomove() that validates the arguments against a known-good * kernel buffer. This function automatically indexes the buffer by * uio_offset and handles all range checking. */ int uiomove_frombuf(void *buf, size_t buflen, struct uio *uio) { size_t offset; offset = (size_t)uio->uio_offset; if ((off_t)offset != uio->uio_offset) return (EINVAL); if (buflen == 0 || offset >= buflen) return (0); return (uiomove((char *)buf + offset, buflen - offset, uio)); } /* * Give next character to user as result of read. */ int ureadc(int c, struct uio *uio) { struct iovec *iov; char *iov_base; 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); } /* * General routine to allocate a hash table. Make the hash table size a * power of 2 greater or equal to the number of elements requested, and * store the masking value in *hashmask. */ void * hashinit(int elements, struct malloc_type *type, u_long *hashmask) { long hashsize; LIST_HEAD(generic, generic) *hashtbl; int i; if (elements <= 0) panic("hashinit: bad elements"); for (hashsize = 2; hashsize < elements; hashsize <<= 1) continue; hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); for (i = 0; i < hashsize; i++) LIST_INIT(&hashtbl[i]); *hashmask = hashsize - 1; return (hashtbl); } void hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask) { LIST_HEAD(generic, generic) *hashtbl, *hp; hashtbl = vhashtbl; for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++) KASSERT(LIST_EMPTY(hp), ("%s: hash not empty", __func__)); kfree(hashtbl, type); } /* * This is a newer version which allocates a hash table of structures. * * The returned array will be zero'd. The caller is responsible for * initializing the structures. */ void * hashinit_ext(int elements, size_t size, struct malloc_type *type, u_long *hashmask) { long hashsize; void *hashtbl; if (elements <= 0) panic("hashinit: bad elements"); for (hashsize = 2; hashsize < elements; hashsize <<= 1) continue; hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO); *hashmask = hashsize - 1; return (hashtbl); } static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 }; #define NPRIMES NELEM(primes) /* * General routine to allocate a prime number sized hash table. */ void * phashinit(int elements, struct malloc_type *type, u_long *nentries) { long hashsize; LIST_HEAD(generic, generic) *hashtbl; int i; if (elements <= 0) panic("phashinit: bad elements"); for (i = 1, hashsize = primes[1]; hashsize <= elements;) { i++; if (i == NPRIMES) break; hashsize = primes[i]; } hashsize = primes[i - 1]; hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); for (i = 0; i < hashsize; i++) LIST_INIT(&hashtbl[i]); *nentries = hashsize; return (hashtbl); } /* * This is a newer version which allocates a hash table of structures * in a prime-number size. * * The returned array will be zero'd. The caller is responsible for * initializing the structures. */ void * phashinit_ext(int elements, size_t size, struct malloc_type *type, u_long *nentries) { long hashsize; void *hashtbl; int i; if (elements <= 0) panic("phashinit: bad elements"); for (i = 1, hashsize = primes[1]; hashsize <= elements;) { i++; if (i == NPRIMES) break; hashsize = primes[i]; } hashsize = primes[i - 1]; hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO); *nentries = hashsize; return (hashtbl); } /* * Copyin an iovec. If the iovec array fits, use the preallocated small * iovec structure. If it is too big, dynamically allocate an iovec array * of sufficient size. * * MPSAFE */ int iovec_copyin(const struct iovec *uiov, struct iovec **kiov, struct iovec *siov, int iov_cnt, size_t *iov_len) { struct iovec *iovp; int error, i; size_t len; if ((u_int)iov_cnt > UIO_MAXIOV) return EMSGSIZE; if (iov_cnt > UIO_SMALLIOV) { *kiov = kmalloc(sizeof(struct iovec) * iov_cnt, M_IOV, M_WAITOK); } else { *kiov = siov; } error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec)); if (error == 0) { *iov_len = 0; for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) { /* * Check for both *iov_len overflows and out of * range iovp->iov_len's. We limit to the * capabilities of signed integers. * * GCC4 - overflow check opt requires assign/test. */ len = *iov_len + iovp->iov_len; if (len < *iov_len) error = EINVAL; *iov_len = len; } } /* * From userland disallow iovec's which exceed the sized size * limit as the system calls return ssize_t. * * NOTE: Internal kernel interfaces can handle the unsigned * limit. */ if (error == 0 && (ssize_t)*iov_len < 0) error = EINVAL; if (error) iovec_free(kiov, siov); return (error); } /* * Copyright (c) 2004 Alan L. Cox * 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. * 3. 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 * $FreeBSD: src/sys/i386/i386/uio_machdep.c,v 1.1 2004/03/21 20:28:36 alc Exp $ */ /* * Implement uiomove(9) from physical memory using lwbuf's to reduce * the creation and destruction of ephemeral mappings. */ int uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, size_t n, struct uio *uio) { struct lwbuf lwb_cache; struct lwbuf *lwb; struct thread *td = curthread; struct iovec *iov; void *cp; vm_offset_t page_offset; vm_page_t m; size_t cnt; int error = 0; int save = 0; KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE, ("uiomove_fromphys: mode")); KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread, ("uiomove_fromphys proc")); crit_enter(); save = td->td_flags & TDF_DEADLKTREAT; td->td_flags |= TDF_DEADLKTREAT; crit_exit(); 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; page_offset = offset & PAGE_MASK; cnt = min(cnt, PAGE_SIZE - page_offset); m = ma[offset >> PAGE_SHIFT]; lwb = lwbuf_alloc(m, &lwb_cache); cp = (char *)lwbuf_kva(lwb) + page_offset; switch (uio->uio_segflg) { case UIO_USERSPACE: /* * note: removed uioyield (it was the wrong place to * put it). */ if (uio->uio_rw == UIO_READ) error = copyout(cp, iov->iov_base, cnt); else error = copyin(iov->iov_base, cp, cnt); if (error) { lwbuf_free(lwb); 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; } lwbuf_free(lwb); iov->iov_base = (char *)iov->iov_base + cnt; iov->iov_len -= cnt; uio->uio_resid -= cnt; uio->uio_offset += cnt; offset += cnt; n -= cnt; } out: if (save == 0) { crit_enter(); td->td_flags &= ~TDF_DEADLKTREAT; crit_exit(); } return (error); }