linux32_dirent.c revision 1.19
1/* $NetBSD: linux32_dirent.c,v 1.19 2018/09/03 16:29:29 riastradh 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 1.19 2018/09/03 16:29:29 riastradh 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 = ENOTDIR; 130 goto out1; 131 } 132 133 vn_lock(vp, LK_SHARED | LK_RETRY); 134 error = VOP_GETATTR(vp, &va, l->l_cred); 135 VOP_UNLOCK(vp); 136 if (error) 137 goto out1; 138 139 nbytes = SCARG(uap, count); 140 if (nbytes == 1) { /* emulating old, broken behaviour */ 141 nbytes = sizeof (idb); 142 buflen = uimax(va.va_blocksize, nbytes); 143 oldcall = 1; 144 } else { 145 buflen = uimin(MAXBSIZE, nbytes); 146 if (buflen < va.va_blocksize) 147 buflen = va.va_blocksize; 148 oldcall = 0; 149 } 150 tbuf = malloc(buflen, M_TEMP, M_WAITOK); 151 152 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 153 off = fp->f_offset; 154again: 155 aiov.iov_base = tbuf; 156 aiov.iov_len = buflen; 157 auio.uio_iov = &aiov; 158 auio.uio_iovcnt = 1; 159 auio.uio_rw = UIO_READ; 160 auio.uio_resid = buflen; 161 auio.uio_offset = off; 162 UIO_SETUP_SYSSPACE(&auio); 163 /* 164 * First we read into the malloc'ed buffer, then 165 * we massage it into user space, one record at a time. 166 */ 167 error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, &cookiebuf, 168 &ncookies); 169 if (error) 170 goto out; 171 172 inp = tbuf; 173 outp = (void *)SCARG_P32(uap, dent); 174 resid = nbytes; 175 if ((len = buflen - auio.uio_resid) == 0) 176 goto eof; 177 178 for (cookie = cookiebuf; len > 0; len -= reclen) { 179 bdp = (struct dirent *)inp; 180 reclen = bdp->d_reclen; 181 if (reclen & 3) { 182 error = EIO; 183 goto out; 184 } 185 if (bdp->d_fileno == 0) { 186 inp += reclen; /* it is a hole; squish it out */ 187 if (cookie) 188 off = *cookie++; 189 else 190 off += reclen; 191 continue; 192 } 193 linux32_reclen = LINUX_RECLEN(&idb, bdp->d_namlen); 194 if (reclen > len || resid < linux32_reclen) { 195 /* entry too big for buffer, so just stop */ 196 outp++; 197 break; 198 } 199 /* 200 * Massage in place to make a Linux-shaped dirent (otherwise 201 * we have to worry about touching user memory outside of 202 * the copyout() call). 203 */ 204 idb.d_ino = bdp->d_fileno; 205 /* 206 * The old readdir() call misuses the offset and reclen fields. 207 */ 208 if (oldcall) { 209 idb.d_off = (linux32_off_t)linux32_reclen; 210 idb.d_reclen = (u_short)bdp->d_namlen; 211 } else { 212 if (sizeof (idb.d_off) <= 4 && (off >> 32) != 0) { 213 compat_offseterr(vp, "linux32_getdents"); 214 error = EINVAL; 215 goto out; 216 } 217 idb.d_off = (linux32_off_t)off; 218 idb.d_reclen = (u_short)linux32_reclen; 219 } 220 size_t dirl = MIN(sizeof(idb.d_name) - 1, bdp->d_namlen + 1); 221 memcpy(idb.d_name, bdp->d_name, dirl); 222 idb.d_name[dirl + 1] = bdp->d_type; 223 if ((error = copyout((void *)&idb, outp, linux32_reclen))) 224 goto out; 225 /* advance past this real entry */ 226 inp += reclen; 227 if (cookie) 228 off = *cookie++; /* each entry points to itself */ 229 else 230 off += reclen; 231 /* advance output past Linux-shaped entry */ 232 outp += linux32_reclen; 233 resid -= linux32_reclen; 234 if (oldcall) 235 break; 236 } 237 238 /* if we squished out the whole block, try again */ 239 if (outp == (void *)SCARG_P32(uap, dent)) { 240 if (cookiebuf) 241 free(cookiebuf, M_TEMP); 242 cookiebuf = NULL; 243 goto again; 244 } 245 fp->f_offset = off; /* update the vnode offset */ 246 247 if (oldcall) 248 nbytes = resid + linux32_reclen; 249 250eof: 251 *retval = nbytes - resid; 252out: 253 VOP_UNLOCK(vp); 254 if (cookiebuf) 255 free(cookiebuf, M_TEMP); 256 free(tbuf, M_TEMP); 257out1: 258 fd_putfile(SCARG(uap, fd)); 259 return error; 260} 261 262int 263linux32_sys_getdents64(struct lwp *l, const struct linux32_sys_getdents64_args *uap, register_t *retval) 264{ 265 /* { 266 syscallarg(int) fd; 267 syscallarg(linux32_dirent64p_t) dent; 268 syscallarg(unsigned int) count; 269 } */ 270 struct linux_sys_getdents64_args ua; 271 272 NETBSD32TO64_UAP(fd); 273 NETBSD32TOP_UAP(dent, struct linux_dirent64); 274 NETBSD32TO64_UAP(count); 275 276 return linux_sys_getdents64(l, &ua, retval); 277} 278 279int 280linux32_sys_readdir(struct lwp *l, const struct linux32_sys_readdir_args *uap, register_t *retval) 281{ 282 /* { 283 syscallarg(int) fd; 284 syscallarg(struct linux32_direntp_t) dent; 285 syscallarg(unsigned int) count; 286 } */ 287 int error; 288 struct linux32_sys_getdents_args da; 289 290 SCARG(&da, fd) = SCARG(uap, fd); 291 SCARG(&da, dent) = SCARG(uap, dent); 292 SCARG(&da, count) = 1; 293 294 error = linux32_sys_getdents(l, &da, retval); 295 if (error == 0 && *retval > 1) 296 *retval = 1; 297 298 return error; 299} 300