lib/libpuffs/requests.c

   1 /*      $NetBSD: requests.c,v 1.24 2013/01/23 20:22:34 riastradh Exp $  */
   2
   3 /*
   4  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
   5  *
   6  * Development of this software was supported by the
   7  * Research Foundation of Helsinki University of Technology
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  19  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 #if !defined(lint)
  33 __RCSID("$NetBSD: requests.c,v 1.24 2013/01/23 20:22:34 riastradh Exp $");
  34 #endif /* !lint */
  35
  36 #include <sys/types.h>
  37 #include <sys/ioctl.h>
  38 #include <sys/queue.h>
  39 #include <sys/socket.h>
  40
  41 #include <dev/putter/putter.h>
  42
  43 #include <assert.h>
  44 #include <errno.h>
  45 #include <puffs.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <unistd.h>
  49
  50 #include "puffs_priv.h"
  51
  52 /*
  53  * Read a frame from the upstream provider.  First read the frame
  54  * length and after this read the actual contents.  Yes, optimize
  55  * me some day.
  56  */
  57 /*ARGSUSED*/
  58 int
  59 puffs__fsframe_read(struct puffs_usermount *pu, struct puffs_framebuf *pb,
  60         int fd, int *done)
  61 {
  62         struct putter_hdr phdr;
  63         void *win;
  64         size_t howmuch, winlen, curoff;
  65         ssize_t n;
  66         int lenstate;
  67
  68         /* How much to read? */
  69  the_next_level:
  70         curoff = puffs_framebuf_telloff(pb);
  71         if (curoff < sizeof(struct putter_hdr)) {
  72                 howmuch = sizeof(struct putter_hdr) - curoff;
  73                 lenstate = 1;
  74         } else {
  75                 puffs_framebuf_getdata_atoff(pb, 0, &phdr, sizeof(phdr));
  76                 /*LINTED*/
  77                 howmuch = phdr.pth_framelen - curoff;
  78                 lenstate = 0;
  79         }
  80
  81         if (puffs_framebuf_reserve_space(pb, howmuch) == -1)
  82                 return errno;
  83
  84         /* Read contents */
  85         while (howmuch) {
  86                 winlen = howmuch;
  87                 curoff = puffs_framebuf_telloff(pb);
  88                 if (puffs_framebuf_getwindow(pb, curoff, &win, &winlen) == -1)
  89                         return errno;
  90                 n = read(fd, win, winlen);
  91                 switch (n) {
  92                 case 0:
  93                         return ECONNRESET;
  94                 case -1:
  95                         if (errno == EAGAIN)
  96                                 return 0;
  97                         return errno;
  98                 default:
  99                         howmuch -= n;
 100                         puffs_framebuf_seekset(pb, curoff + n);
 101                         break;
 102                 }
 103         }
 104
 105         if (lenstate)
 106                 goto the_next_level;
 107
 108         puffs_framebuf_seekset(pb, 0);
 109         *done = 1;
 110         return 0;
 111 }
 112
 113 /*
 114  * Write a frame upstream
 115  */
 116 /*ARGSUSED*/
 117 int
 118 puffs__fsframe_write(struct puffs_usermount *pu, struct puffs_framebuf *pb,
 119         int fd, int *done)
 120 {
 121         void *win;
 122         uint64_t flen;
 123         size_t winlen, howmuch, curoff;
 124         ssize_t n;
 125         int rv;
 126
 127         /*
 128          * Finalize it if we haven't written anything yet (or we're still
 129          * attempting to write the first byte)
 130          *
 131          * XXX: this shouldn't be here
 132          */
 133         if (puffs_framebuf_telloff(pb) == 0) {
 134                 struct puffs_req *preq;
 135
 136                 winlen = sizeof(struct puffs_req);
 137                 rv = puffs_framebuf_getwindow(pb, 0, (void *)&preq, &winlen);
 138                 if (rv == -1)
 139                         return errno;
 140                 preq->preq_pth.pth_framelen = flen = preq->preq_buflen;
 141         } else {
 142                 struct putter_hdr phdr;
 143
 144                 puffs_framebuf_getdata_atoff(pb, 0, &phdr, sizeof(phdr));
 145                 flen = phdr.pth_framelen;
 146         }
 147
 148         /*
 149          * Then write it.  Chances are if we are talking to the kernel it'll
 150          * just shlosh in all at once, but if we're e.g. talking to the
 151          * network it might take a few tries.
 152          */
 153         /*LINTED*/
 154         howmuch = flen - puffs_framebuf_telloff(pb);
 155
 156         while (howmuch) {
 157                 winlen = howmuch;
 158                 curoff = puffs_framebuf_telloff(pb);
 159                 if (puffs_framebuf_getwindow(pb, curoff, &win, &winlen) == -1)
 160                         return errno;
 161
 162                 /*
 163                  * XXX: we know from the framebuf implementation that we
 164                  * will always managed to map the entire window.  But if
 165                  * that changes, this will catch it.  Then we can do stuff
 166                  * iov stuff instead.
 167                  */
 168                 assert(winlen == howmuch);
 169
 170                 /* XXX: want NOSIGNAL if writing to a pipe */
 171 #if 0
 172                 n = send(fd, win, winlen, MSG_NOSIGNAL);
 173 #else
 174                 n = write(fd, win, winlen);
 175 #endif
 176                 switch (n) {
 177                 case 0:
 178                         return ECONNRESET;
 179                 case -1:
 180                         if (errno == EAGAIN)
 181                                 return 0;
 182                         return errno;
 183                 default:
 184                         howmuch -= n;
 185                         puffs_framebuf_seekset(pb, curoff + n);
 186                         break;
 187                 }
 188         }
 189
 190         *done = 1;
 191         return 0;
 192 }
 193
 194 /*
 195  * Compare if "pb1" is a response to a previously sent frame pb2.
 196  * More often than not "pb1" is not a response to anything but
 197  * rather a fresh request from the kernel.
 198  */
 199 /*ARGSUSED*/
 200 int
 201 puffs__fsframe_cmp(struct puffs_usermount *pu,
 202         struct puffs_framebuf *pb1, struct puffs_framebuf *pb2, int *notresp)
 203 {
 204         struct puffs_req *preq1, *preq2;
 205         size_t winlen;
 206         int rv;
 207
 208         /* map incoming preq */
 209         winlen = sizeof(struct puffs_req);
 210         rv = puffs_framebuf_getwindow(pb1, 0, (void *)&preq1, &winlen);
 211         assert(rv == 0); /* frames are always at least puffs_req in size */
 212         assert(winlen == sizeof(struct puffs_req));
 213
 214         /*
 215          * Check if this is not a response in this slot.  That's the
 216          * likely case.
 217          */
 218         if ((preq1->preq_opclass & PUFFSOPFLAG_ISRESPONSE) == 0) {
 219                 *notresp = 1;
 220                 return 0;
 221         }
 222
 223         /* map second preq */
 224         winlen = sizeof(struct puffs_req);
 225         rv = puffs_framebuf_getwindow(pb2, 0, (void *)&preq2, &winlen);
 226         assert(rv == 0); /* frames are always at least puffs_req in size */
 227         assert(winlen == sizeof(struct puffs_req));
 228
 229         /* then compare: resid equal? */
 230         return preq1->preq_id != preq2->preq_id;
 231 }
 232
 233 void
 234 puffs__fsframe_gotframe(struct puffs_usermount *pu, struct puffs_framebuf *pb)
 235 {
 236
 237         puffs_framebuf_seekset(pb, 0);
 238         puffs__ml_dispatch(pu, pb);
 239 }