linux32_dirent.c revision 1.7
1/* $NetBSD: linux32_dirent.c,v 1.7 2008/11/19 18:36:04 ad Exp $ */ 2 3/*- 4 * Copyright (c) 2006 Emmanuel Dreyfus, all rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Emmanuel Dreyfus 17 * 4. The name of the author may not be used to endorse or promote 18 * products derived from this software without specific prior written 19 * permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS'' 22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34#include <sys/cdefs.h> 35 36__KERNEL_RCSID(0, "$NetBSD: linux32_dirent.c,v 1.7 2008/11/19 18:36:04 ad Exp $"); 37 38#include <sys/types.h> 39#include <sys/param.h> 40#include <sys/fstypes.h> 41#include <sys/signal.h> 42#include <sys/dirent.h> 43#include <sys/kernel.h> 44#include <sys/fcntl.h> 45#include <sys/file.h> 46#include <sys/filedesc.h> 47#include <sys/malloc.h> 48#include <sys/select.h> 49#include <sys/proc.h> 50#include <sys/ucred.h> 51#include <sys/vnode.h> 52#include <sys/swap.h> 53 54#include <machine/types.h> 55 56#include <sys/syscallargs.h> 57 58#include <compat/netbsd32/netbsd32.h> 59#include <compat/netbsd32/netbsd32_conv.h> 60#include <compat/netbsd32/netbsd32_syscallargs.h> 61 62#include <compat/linux/common/linux_types.h> 63#include <compat/linux/common/linux_signal.h> 64#include <compat/linux/common/linux_machdep.h> 65#include <compat/linux/common/linux_misc.h> 66#include <compat/linux/common/linux_oldolduname.h> 67#include <compat/linux/common/linux_dirent.h> 68#include <compat/linux/common/linux_ipc.h> 69#include <compat/linux/common/linux_sem.h> 70#include <compat/linux/linux_syscallargs.h> 71 72#include <compat/linux32/common/linux32_types.h> 73#include <compat/linux32/common/linux32_signal.h> 74#include <compat/linux32/common/linux32_machdep.h> 75#include <compat/linux32/common/linux32_sysctl.h> 76#include <compat/linux32/common/linux32_socketcall.h> 77#include <compat/linux32/linux32_syscallargs.h> 78 79/* 80 * Linux 'readdir' call. This code is mostly taken from the 81 * SunOS getdents call (see compat/sunos/sunos_misc.c), though 82 * an attempt has been made to keep it a little cleaner (failing 83 * miserably, because of the cruft needed if count 1 is passed). 84 * 85 * The d_off field should contain the offset of the next valid entry, 86 * but in Linux it has the offset of the entry itself. We emulate 87 * that bug here. 88 * 89 * Read in BSD-style entries, convert them, and copy them out. 90 * 91 * Note that this doesn't handle union-mounted filesystems. 92 */ 93 94int 95linux32_sys_getdents(struct lwp *l, const struct linux32_sys_getdents_args *uap, register_t *retval) 96{ 97 /* { 98 syscallarg(int) fd; 99 syscallarg(linux32_direntp_t) dent; 100 syscallarg(unsigned int) count; 101 } */ 102 struct dirent *bdp; 103 struct vnode *vp; 104 char *inp, *tbuf; /* BSD-format */ 105 int len, reclen; /* BSD-format */ 106 char *outp; /* Linux-format */ 107 int resid, linux32_reclen = 0; /* Linux-format */ 108 struct file *fp; 109 struct uio auio; 110 struct iovec aiov; 111 struct linux32_dirent idb; 112 off_t off; /* true file offset */ 113 int buflen, error, eofflag, nbytes, oldcall; 114 struct vattr va; 115 off_t *cookiebuf = NULL, *cookie; 116 int ncookies; 117 118 /* fd_getvnode() will use the descriptor for us */ 119 if ((error = fd_getvnode(SCARG(uap, fd), &fp)) != 0) 120 return (error); 121 122 if ((fp->f_flag & FREAD) == 0) { 123 error = EBADF; 124 goto out1; 125 } 126 127 vp = (struct vnode *)fp->f_data; 128 if (vp->v_type != VDIR) { 129 error = EINVAL; 130 goto out1; 131 } 132 133 if ((error = VOP_GETATTR(vp, &va, l->l_cred))) 134 goto out1; 135 136 nbytes = SCARG(uap, count); 137 if (nbytes == 1) { /* emulating old, broken behaviour */ 138 nbytes = sizeof (idb); 139 buflen = max(va.va_blocksize, nbytes); 140 oldcall = 1; 141 } else { 142 buflen = min(MAXBSIZE, nbytes); 143 if (buflen < va.va_blocksize) 144 buflen = va.va_blocksize; 145 oldcall = 0; 146 } 147 tbuf = malloc(buflen, M_TEMP, M_WAITOK); 148 149 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 150 off = fp->f_offset; 151again: 152 aiov.iov_base = tbuf; 153 aiov.iov_len = buflen; 154 auio.uio_iov = &aiov; 155 auio.uio_iovcnt = 1; 156 auio.uio_rw = UIO_READ; 157 auio.uio_resid = buflen; 158 auio.uio_offset = off; 159 UIO_SETUP_SYSSPACE(&auio); 160 /* 161 * First we read into the malloc'ed buffer, then 162 * we massage it into user space, one record at a time. 163 */ 164 error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, &cookiebuf, 165 &ncookies); 166 if (error) 167 goto out; 168 169 inp = tbuf; 170 outp = (void *)SCARG_P32(uap, dent); 171 resid = nbytes; 172 if ((len = buflen - auio.uio_resid) == 0) 173 goto eof; 174 175 for (cookie = cookiebuf; len > 0; len -= reclen) { 176 bdp = (struct dirent *)inp; 177 reclen = bdp->d_reclen; 178 if (reclen & 3) 179 panic("linux32_readdir"); 180 if (bdp->d_fileno == 0) { 181 inp += reclen; /* it is a hole; squish it out */ 182 if (cookie) 183 off = *cookie++; 184 else 185 off += reclen; 186 continue; 187 } 188 linux32_reclen = LINUX_RECLEN(&idb, bdp->d_namlen); 189 if (reclen > len || resid < linux32_reclen) { 190 /* entry too big for buffer, so just stop */ 191 outp++; 192 break; 193 } 194 /* 195 * Massage in place to make a Linux-shaped dirent (otherwise 196 * we have to worry about touching user memory outside of 197 * the copyout() call). 198 */ 199 idb.d_ino = bdp->d_fileno; 200 /* 201 * The old readdir() call misuses the offset and reclen fields. 202 */ 203 if (oldcall) { 204 idb.d_off = (linux32_off_t)linux32_reclen; 205 idb.d_reclen = (u_short)bdp->d_namlen; 206 } else { 207 if (sizeof (idb.d_off) <= 4 && (off >> 32) != 0) { 208 compat_offseterr(vp, "linux32_getdents"); 209 error = EINVAL; 210 goto out; 211 } 212 idb.d_off = (linux32_off_t)off; 213 idb.d_reclen = (u_short)linux32_reclen; 214 } 215 strcpy(idb.d_name, bdp->d_name); 216 if ((error = copyout((void *)&idb, outp, linux32_reclen))) 217 goto out; 218 /* advance past this real entry */ 219 inp += reclen; 220 if (cookie) 221 off = *cookie++; /* each entry points to itself */ 222 else 223 off += reclen; 224 /* advance output past Linux-shaped entry */ 225 outp += linux32_reclen; 226 resid -= linux32_reclen; 227 if (oldcall) 228 break; 229 } 230 231 /* if we squished out the whole block, try again */ 232 if (outp == (void *)SCARG_P32(uap, dent)) 233 goto again; 234 fp->f_offset = off; /* update the vnode offset */ 235 236 if (oldcall) 237 nbytes = resid + linux32_reclen; 238 239eof: 240 *retval = nbytes - resid; 241out: 242 VOP_UNLOCK(vp, 0); 243 if (cookiebuf) 244 free(cookiebuf, M_TEMP); 245 free(tbuf, M_TEMP); 246out1: 247 fd_putfile(SCARG(uap, fd)); 248 return error; 249} 250 251int 252linux32_sys_getdents64(struct lwp *l, const struct linux32_sys_getdents64_args *uap, register_t *retval) 253{ 254 /* { 255 syscallcarg(int) fd; 256 syscallcarg(linux32_dirent64p_t) dent; 257 syscallcarg(unsigned int) count; 258 } */ 259 struct linux_sys_getdents64_args ua; 260 261 NETBSD32TO64_UAP(fd); 262 NETBSD32TOP_UAP(dent, struct linux_dirent64); 263 NETBSD32TO64_UAP(count); 264 265 return linux_sys_getdents64(l, &ua, retval); 266} 267 268int 269linux32_sys_readdir(struct lwp *l, const struct linux32_sys_readdir_args *uap, register_t *retval) 270{ 271 /* { 272 syscallarg(int) fd; 273 syscallarg(struct linux32_direntp_t) dent; 274 syscallarg(unsigned int) count; 275 } */ 276 int error; 277 struct linux32_sys_getdents_args da; 278 279 SCARG(&da, fd) = SCARG(uap, fd); 280 SCARG(&da, dent) = SCARG(uap, dent); 281 SCARG(&da, count) = 1; 282 283 error = linux32_sys_getdents(l, &da, retval); 284 if (error == 0 && *retval > 1) 285 *retval = 1; 286 287 return error; 288} 289