source/lib/sendfile.c

   1 /*
   2  Unix SMB/Netbios implementation.
   3  Version 2.2.x / 3.0.x
   4  sendfile implementations.
   5  Copyright (C) Jeremy Allison 2002.
   6
   7  This program is free software; you can redistribute it and/or modify
   8  it under the terms of the GNU General Public License as published by
   9  the Free Software Foundation; either version 2 of the License, or
  10  (at your option) any later version.
  11  This program is distributed in the hope that it will be useful,
  12  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  GNU General Public License for more details.
  15
  16  You should have received a copy of the GNU General Public License
  17  along with this program; if not, write to the Free Software
  18  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 /*
  22  * This file handles the OS dependent sendfile implementations.
  23  * The API is such that it returns -1 on error, else returns the
  24  * number of bytes written.
  25  */
  26
  27 #include "includes.h"
  28
  29 #if defined(LINUX_SENDFILE_API)
  30
  31 #include <sys/sendfile.h>
  32
  33 #ifndef MSG_MORE
  34 #define MSG_MORE 0x8000
  35 #endif
  36
  37 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
  38 {
  39         size_t total=0;
  40         ssize_t ret;
  41         ssize_t hdr_len = 0;
  42
  43         /*
  44          * Send the header first.
  45          * Use MSG_MORE to cork the TCP output until sendfile is called.
  46          */
  47
  48         if (header) {
  49                 hdr_len = header->length;
  50                 while (total < hdr_len) {
  51                         ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
  52                         if (ret == -1)
  53                                 return -1;
  54                         total += ret;
  55                 }
  56         }
  57
  58         total = count;
  59         while (total) {
  60                 ssize_t nwritten;
  61                 do {
  62 #if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_SENDFILE64)
  63                         nwritten = sendfile64(tofd, fromfd, &offset, total);
  64 #else
  65                         nwritten = sendfile(tofd, fromfd, &offset, total);
  66 #endif
  67                 } while (nwritten == -1 && errno == EINTR);
  68                 if (nwritten == -1)
  69                         return -1;
  70                 if (nwritten == 0)
  71                         return -1; /* I think we're at EOF here... */
  72                 total -= nwritten;
  73         }
  74         return count + hdr_len;
  75 }
  76
  77 #elif defined(LINUX_BROKEN_SENDFILE_API)
  78
  79 /*
  80  * We must use explicit 32 bit types here. This code path means Linux
  81  * won't do proper 64-bit sendfile. JRA.
  82  */
  83
  84 extern int32 sendfile (int out_fd, int in_fd, int32 *offset, uint32 count);
  85
  86
  87 #ifndef MSG_MORE
  88 #define MSG_MORE 0x8000
  89 #endif
  90
  91 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
  92 {
  93         size_t total=0;
  94         ssize_t ret;
  95         ssize_t hdr_len = 0;
  96         uint32 small_total = 0;
  97         int32 small_offset;
  98
  99         /*
 100          * Fix for broken Linux 2.4 systems with no working sendfile64().
 101          * If the offset+count > 2 GB then pretend we don't have the
 102          * system call sendfile at all. The upper layer catches this
 103          * and uses a normal read. JRA.
 104          */
 105
 106         if ((sizeof(SMB_OFF_T) >= 8) && (offset + count > (SMB_OFF_T)0x7FFFFFFF)) {
 107                 errno = ENOSYS;
 108                 return -1;
 109         }
 110
 111         /*
 112          * Send the header first.
 113          * Use MSG_MORE to cork the TCP output until sendfile is called.
 114          */
 115
 116         if (header) {
 117                 hdr_len = header->length;
 118                 while (total < hdr_len) {
 119                         ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
 120                         if (ret == -1)
 121                                 return -1;
 122                         total += ret;
 123                 }
 124         }
 125
 126         small_total = (uint32)count;
 127         small_offset = (int32)offset;
 128
 129         while (small_total) {
 130                 int32 nwritten;
 131                 do {
 132                         nwritten = sendfile(tofd, fromfd, &small_offset, small_total);
 133                 } while (nwritten == -1 && errno == EINTR);
 134                 if (nwritten == -1)
 135                         return -1;
 136                 if (nwritten == 0)
 137                         return -1; /* I think we're at EOF here... */
 138                 small_total -= nwritten;
 139         }
 140         return count + hdr_len;
 141 }
 142
 143
 144 #elif defined(SOLARIS_SENDFILE_API)
 145
 146 /* Hmmm. Can't find Solaris sendfile API docs.... Where is it ? */
 147 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
 148 {
 149         errno = ENOSYS;
 150         return -1;
 151 }
 152
 153 #elif defined(HPUX_SENDFILE_API)
 154
 155 #include <sys/socket.h>
 156 #include <sys/uio.h>
 157
 158 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
 159 {
 160         size_t total=0;
 161         struct iovec hdtrl[2];
 162         size_t hdr_len = 0;
 163
 164         if (header) {
 165                 /* Set up the header/trailer iovec. */
 166                 hdtrl[0].iov_base = header->data;
 167                 hdtrl[0].iov_len = hdr_len = header->length;
 168         } else {
 169                 hdtrl[0].iov_base = NULL;
 170                 hdtrl[0].iov_len = hdr_len = 0;
 171         }
 172         hdtrl[1].iov_base = NULL;
 173         hdtrl[1].iov_base = 0;
 174
 175         total = count;
 176         while (total + hdtrl[0].iov_len) {
 177                 ssize_t nwritten;
 178
 179                 /*
 180                  * HPUX guarantees that if any data was written before
 181                  * a signal interrupt then sendfile returns the number of
 182                  * bytes written (which may be less than requested) not -1.
 183                  * nwritten includes the header data sent.
 184                  */
 185
 186                 do {
 187 #if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_SENDFILE64)
 188                         nwritten = sendfile64(tofd, fromfd, offset, total, &hdtrl[0], 0);
 189 #else
 190                         nwritten = sendfile(tofd, fromfd, offset, total, &hdtrl[0], 0);
 191 #endif
 192                 } while (nwritten == -1 && errno == EINTR);
 193                 if (nwritten == -1)
 194                         return -1;
 195                 if (nwritten == 0)
 196                         return -1; /* I think we're at EOF here... */
 197
 198                 /*
 199                  * If this was a short (signal interrupted) write we may need
 200                  * to subtract it from the header data, or null out the header
 201                  * data altogether if we wrote more than hdtrl[0].iov_len bytes.
 202                  * We change nwritten to be the number of file bytes written.
 203                  */
 204
 205                 if (hdtrl[0].iov_base && hdtrl[0].iov_len) {
 206                         if (nwritten >= hdtrl[0].iov_len) {
 207                                 nwritten -= hdtrl[0].iov_len;
 208                                 hdtrl[0].iov_base = NULL;
 209                                 hdtrl[0].iov_len = 0;
 210                         } else {
 211                                 nwritten = 0;
 212                                 /* iov_base is defined as a void *... */
 213                                 hdtrl[0].iov_base = ((char *)hdtrl[0].iov_base) + nwritten;
 214                                 hdtrl[0].iov_len -= nwritten;
 215                         }
 216                 }
 217                 total -= nwritten;
 218                 offset += nwritten;
 219         }
 220         return count + hdr_len;
 221 }
 222
 223 #elif defined(FREEBSD_SENDFILE_API)
 224
 225 #include <sys/types.h>
 226 #include <sys/socket.h>
 227 #include <sys/uio.h>
 228
 229 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
 230 {
 231         size_t total=0;
 232         struct sf_hdtr hdr;
 233         struct iovec hdtrl;
 234         size_t hdr_len = 0;
 235
 236         hdr->headers = &hdtrl;
 237         hdr->hdr_cnt = 1;
 238         hdr->trailers = NULL;
 239         hdr->trl_cnt = 0;
 240
 241         /* Set up the header iovec. */
 242         if (header) {
 243                 hdtrl.iov_base = header->data;
 244                 hdtrl.iov_len = hdr_len = header->length;
 245         } else {
 246                 hdtrl.iov_base = NULL;
 247                 hdtrl.iov_len = 0;
 248         }
 249
 250         total = count;
 251         while (total + hdtrl.iov_len) {
 252                 SMB_OFF_T nwritten;
 253                 int ret;
 254
 255                 /*
 256                  * FreeBSD sendfile returns 0 on success, -1 on error.
 257                  * Remember, the tofd and fromfd are reversed..... :-).
 258                  * nwritten includes the header data sent.
 259                  */
 260
 261                 do {
 262                         ret = sendfile(fromfd, tofd, offset, total, &hdr, &nwritten, 0);
 263                 } while (ret == -1 && errno == EINTR);
 264                 if (ret == -1)
 265                         return -1;
 266
 267                 if (nwritten == 0)
 268                         return -1; /* I think we're at EOF here... */
 269
 270                 /*
 271                  * If this was a short (signal interrupted) write we may need
 272                  * to subtract it from the header data, or null out the header
 273                  * data altogether if we wrote more than hdtrl.iov_len bytes.
 274                  * We change nwritten to be the number of file bytes written.
 275                  */
 276
 277                 if (hdtrl[0].iov_base && hdtrl.iov_len) {
 278                         if (nwritten >= hdtrl.iov_len) {
 279                                 nwritten -= hdtrl.iov_len;
 280                                 hdtrl.iov_base = NULL;
 281                                 hdtrl.iov_len = 0;
 282                         } else {
 283                                 nwritten = 0;
 284                                 hdtrl.iov_base += nwritten;
 285                                 hdtrl.iov_len -= nwritten;
 286                         }
 287                 }
 288                 total -= nwritten;
 289                 offset += nwritten;
 290         }
 291         return count + hdr_len;
 292 }
 293
 294 #else /* No sendfile implementation. Return error. */
 295
 296 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
 297 {
 298         /* No sendfile syscall. */
 299         errno = ENOSYS;
 300         return -1;
 301 }
 302 #endif