lib/stream-fd.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2012 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "stream-fd.h"
  19 #include <assert.h>
  20 #include <errno.h>
  21 #include <poll.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/socket.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27 #include "fatal-signal.h"
  28 #include "leak-checker.h"
  29 #include "poll-loop.h"
  30 #include "socket-util.h"
  31 #include "stress.h"
  32 #include "util.h"
  33 #include "stream-provider.h"
  34 #include "stream.h"
  35 #include "vlog.h"
  36
  37 VLOG_DEFINE_THIS_MODULE(stream_fd);
  38
  39 /* Active file descriptor stream. */
  40
  41 struct stream_fd
  42 {
  43     struct stream stream;
  44     int fd;
  45 };
  46
  47 static const struct stream_class stream_fd_class;
  48
  49 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
  50
  51 static void maybe_unlink_and_free(char *path);
  52
  53 /* Creates a new stream named 'name' that will send and receive data on 'fd'
  54  * and stores a pointer to the stream in '*streamp'.  Initial connection status
  55  * 'connect_status' is interpreted as described for stream_init().
  56  *
  57  * Returns 0 if successful, otherwise a positive errno value.  (The current
  58  * implementation never fails.) */
  59 int
  60 new_fd_stream(const char *name, int fd, int connect_status,
  61               struct stream **streamp)
  62 {
  63     struct stream_fd *s;
  64
  65     s = xmalloc(sizeof *s);
  66     stream_init(&s->stream, &stream_fd_class, connect_status, name);
  67     s->fd = fd;
  68     *streamp = &s->stream;
  69     return 0;
  70 }
  71
  72 static struct stream_fd *
  73 stream_fd_cast(struct stream *stream)
  74 {
  75     stream_assert_class(stream, &stream_fd_class);
  76     return CONTAINER_OF(stream, struct stream_fd, stream);
  77 }
  78
  79 static void
  80 fd_close(struct stream *stream)
  81 {
  82     struct stream_fd *s = stream_fd_cast(stream);
  83     close(s->fd);
  84     free(s);
  85 }
  86
  87 static int
  88 fd_connect(struct stream *stream)
  89 {
  90     struct stream_fd *s = stream_fd_cast(stream);
  91     return check_connection_completion(s->fd);
  92 }
  93
  94 STRESS_OPTION(
  95     stream_flaky_recv, "simulate failure of fd stream recvs",
  96     100, 0, -1, 0);
  97
  98 static ssize_t
  99 fd_recv(struct stream *stream, void *buffer, size_t n)
 100 {
 101     struct stream_fd *s = stream_fd_cast(stream);
 102     ssize_t retval;
 103
 104     if (STRESS(stream_flaky_recv)) {
 105         return -EIO;
 106     }
 107
 108     retval = read(s->fd, buffer, n);
 109     return retval >= 0 ? retval : -errno;
 110 }
 111
 112 STRESS_OPTION(
 113     stream_flaky_send, "simulate failure of fd stream sends",
 114     100, 0, -1, 0);
 115
 116 static ssize_t
 117 fd_send(struct stream *stream, const void *buffer, size_t n)
 118 {
 119     struct stream_fd *s = stream_fd_cast(stream);
 120     ssize_t retval;
 121
 122     if (STRESS(stream_flaky_send)) {
 123         return -EIO;
 124     }
 125
 126     retval = write(s->fd, buffer, n);
 127     return (retval > 0 ? retval
 128             : retval == 0 ? -EAGAIN
 129             : -errno);
 130 }
 131
 132 static void
 133 fd_wait(struct stream *stream, enum stream_wait_type wait)
 134 {
 135     struct stream_fd *s = stream_fd_cast(stream);
 136     switch (wait) {
 137     case STREAM_CONNECT:
 138     case STREAM_SEND:
 139         poll_fd_wait(s->fd, POLLOUT);
 140         break;
 141
 142     case STREAM_RECV:
 143         poll_fd_wait(s->fd, POLLIN);
 144         break;
 145
 146     default:
 147         NOT_REACHED();
 148     }
 149 }
 150
 151 static const struct stream_class stream_fd_class = {
 152     "fd",                       /* name */
 153     NULL,                       /* open */
 154     fd_close,                   /* close */
 155     fd_connect,                 /* connect */
 156     fd_recv,                    /* recv */
 157     fd_send,                    /* send */
 158     NULL,                       /* run */
 159     NULL,                       /* run_wait */
 160     fd_wait,                    /* wait */
 161 };
 162 \f
 163 /* Passive file descriptor stream. */
 164
 165 struct fd_pstream
 166 {
 167     struct pstream pstream;
 168     int fd;
 169     int (*accept_cb)(int fd, const struct sockaddr *, size_t sa_len,
 170                      struct stream **);
 171     char *unlink_path;
 172 };
 173
 174 static struct pstream_class fd_pstream_class;
 175
 176 static struct fd_pstream *
 177 fd_pstream_cast(struct pstream *pstream)
 178 {
 179     pstream_assert_class(pstream, &fd_pstream_class);
 180     return CONTAINER_OF(pstream, struct fd_pstream, pstream);
 181 }
 182
 183 /* Creates a new pstream named 'name' that will accept new socket connections
 184  * on 'fd' and stores a pointer to the stream in '*pstreamp'.
 185  *
 186  * When a connection has been accepted, 'accept_cb' will be called with the new
 187  * socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
 188  * accept_cb must return 0 if the connection is successful, in which case it
 189  * must initialize '*streamp' to the new stream, or a positive errno value on
 190  * error.  In either case accept_cb takes ownership of the 'fd' passed in.
 191  *
 192  * When '*pstreamp' is closed, then 'unlink_path' (if nonnull) will be passed
 193  * to fatal_signal_unlink_file_now() and freed with free().
 194  *
 195  * Returns 0 if successful, otherwise a positive errno value.  (The current
 196  * implementation never fails.) */
 197 int
 198 new_fd_pstream(const char *name, int fd,
 199                int (*accept_cb)(int fd, const struct sockaddr *sa,
 200                                 size_t sa_len, struct stream **streamp),
 201                char *unlink_path, struct pstream **pstreamp)
 202 {
 203     struct fd_pstream *ps = xmalloc(sizeof *ps);
 204     pstream_init(&ps->pstream, &fd_pstream_class, name);
 205     ps->fd = fd;
 206     ps->accept_cb = accept_cb;
 207     ps->unlink_path = unlink_path;
 208     *pstreamp = &ps->pstream;
 209     return 0;
 210 }
 211
 212 static void
 213 pfd_close(struct pstream *pstream)
 214 {
 215     struct fd_pstream *ps = fd_pstream_cast(pstream);
 216     close(ps->fd);
 217     maybe_unlink_and_free(ps->unlink_path);
 218     free(ps);
 219 }
 220
 221 static int
 222 pfd_accept(struct pstream *pstream, struct stream **new_streamp)
 223 {
 224     struct fd_pstream *ps = fd_pstream_cast(pstream);
 225     struct sockaddr_storage ss;
 226     socklen_t ss_len = sizeof ss;
 227     int new_fd;
 228     int retval;
 229
 230     new_fd = accept(ps->fd, (struct sockaddr *) &ss, &ss_len);
 231     if (new_fd < 0) {
 232         retval = errno;
 233         if (retval != EAGAIN) {
 234             VLOG_DBG_RL(&rl, "accept: %s", strerror(retval));
 235         }
 236         return retval;
 237     }
 238
 239     retval = set_nonblocking(new_fd);
 240     if (retval) {
 241         close(new_fd);
 242         return retval;
 243     }
 244
 245     return ps->accept_cb(new_fd, (const struct sockaddr *) &ss, ss_len,
 246                          new_streamp);
 247 }
 248
 249 static void
 250 pfd_wait(struct pstream *pstream)
 251 {
 252     struct fd_pstream *ps = fd_pstream_cast(pstream);
 253     poll_fd_wait(ps->fd, POLLIN);
 254 }
 255
 256 static struct pstream_class fd_pstream_class = {
 257     "pstream",
 258     NULL,
 259     pfd_close,
 260     pfd_accept,
 261     pfd_wait
 262 };
 263 \f
 264 /* Helper functions. */
 265 static void
 266 maybe_unlink_and_free(char *path)
 267 {
 268     if (path) {
 269         fatal_signal_unlink_file_now(path);
 270         free(path);
 271     }
 272 }