lib/stream-fd.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2012 Nicira, Inc.
   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 <errno.h>
  20 #include <poll.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/socket.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26 #include "fatal-signal.h"
  27 #include "leak-checker.h"
  28 #include "poll-loop.h"
  29 #include "socket-util.h"
  30 #include "stress.h"
  31 #include "util.h"
  32 #include "stream-provider.h"
  33 #include "stream.h"
  34 #include "vlog.h"
  35
  36 VLOG_DEFINE_THIS_MODULE(stream_fd);
  37
  38 /* Active file descriptor stream. */
  39
  40 struct stream_fd
  41 {
  42     struct stream stream;
  43     int fd;
  44 };
  45
  46 static const struct stream_class stream_fd_class;
  47
  48 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
  49
  50 static void maybe_unlink_and_free(char *path);
  51
  52 /* Creates a new stream named 'name' that will send and receive data on 'fd'
  53  * and stores a pointer to the stream in '*streamp'.  Initial connection status
  54  * 'connect_status' is interpreted as described for stream_init().
  55  *
  56  * Returns 0 if successful, otherwise a positive errno value.  (The current
  57  * implementation never fails.) */
  58 int
  59 new_fd_stream(const char *name, int fd, int connect_status,
  60               struct stream **streamp)
  61 {
  62     struct stream_fd *s;
  63
  64     s = xmalloc(sizeof *s);
  65     stream_init(&s->stream, &stream_fd_class, connect_status, name);
  66     s->fd = fd;
  67     *streamp = &s->stream;
  68     return 0;
  69 }
  70
  71 static struct stream_fd *
  72 stream_fd_cast(struct stream *stream)
  73 {
  74     stream_assert_class(stream, &stream_fd_class);
  75     return CONTAINER_OF(stream, struct stream_fd, stream);
  76 }
  77
  78 static void
  79 fd_close(struct stream *stream)
  80 {
  81     struct stream_fd *s = stream_fd_cast(stream);
  82     close(s->fd);
  83     free(s);
  84 }
  85
  86 static int
  87 fd_connect(struct stream *stream)
  88 {
  89     struct stream_fd *s = stream_fd_cast(stream);
  90     return check_connection_completion(s->fd);
  91 }
  92
  93 STRESS_OPTION(
  94     stream_flaky_recv, "simulate failure of fd stream recvs",
  95     100, 0, -1, 0);
  96
  97 static ssize_t
  98 fd_recv(struct stream *stream, void *buffer, size_t n)
  99 {
 100     struct stream_fd *s = stream_fd_cast(stream);
 101     ssize_t retval;
 102
 103     if (STRESS(stream_flaky_recv)) {
 104         return -EIO;
 105     }
 106
 107     retval = read(s->fd, buffer, n);
 108     return retval >= 0 ? retval : -errno;
 109 }
 110
 111 STRESS_OPTION(
 112     stream_flaky_send, "simulate failure of fd stream sends",
 113     100, 0, -1, 0);
 114
 115 static ssize_t
 116 fd_send(struct stream *stream, const void *buffer, size_t n)
 117 {
 118     struct stream_fd *s = stream_fd_cast(stream);
 119     ssize_t retval;
 120
 121     if (STRESS(stream_flaky_send)) {
 122         return -EIO;
 123     }
 124
 125     retval = write(s->fd, buffer, n);
 126     return (retval > 0 ? retval
 127             : retval == 0 ? -EAGAIN
 128             : -errno);
 129 }
 130
 131 static void
 132 fd_wait(struct stream *stream, enum stream_wait_type wait)
 133 {
 134     struct stream_fd *s = stream_fd_cast(stream);
 135     switch (wait) {
 136     case STREAM_CONNECT:
 137     case STREAM_SEND:
 138         poll_fd_wait(s->fd, POLLOUT);
 139         break;
 140
 141     case STREAM_RECV:
 142         poll_fd_wait(s->fd, POLLIN);
 143         break;
 144
 145     default:
 146         NOT_REACHED();
 147     }
 148 }
 149
 150 static const struct stream_class stream_fd_class = {
 151     "fd",                       /* name */
 152     false,                      /* needs_probes */
 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     int (*set_dscp_cb)(int fd, uint8_t dscp);
 172     char *unlink_path;
 173 };
 174
 175 static struct pstream_class fd_pstream_class;
 176
 177 static struct fd_pstream *
 178 fd_pstream_cast(struct pstream *pstream)
 179 {
 180     pstream_assert_class(pstream, &fd_pstream_class);
 181     return CONTAINER_OF(pstream, struct fd_pstream, pstream);
 182 }
 183
 184 /* Creates a new pstream named 'name' that will accept new socket connections
 185  * on 'fd' and stores a pointer to the stream in '*pstreamp'.
 186  *
 187  * When a connection has been accepted, 'accept_cb' will be called with the new
 188  * socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
 189  * accept_cb must return 0 if the connection is successful, in which case it
 190  * must initialize '*streamp' to the new stream, or a positive errno value on
 191  * error.  In either case accept_cb takes ownership of the 'fd' passed in.
 192  *
 193  * When '*pstreamp' is closed, then 'unlink_path' (if nonnull) will be passed
 194  * to fatal_signal_unlink_file_now() and freed with free().
 195  *
 196  * Returns 0 if successful, otherwise a positive errno value.  (The current
 197  * implementation never fails.) */
 198 int
 199 new_fd_pstream(const char *name, int fd,
 200                int (*accept_cb)(int fd, const struct sockaddr *sa,
 201                                 size_t sa_len, struct stream **streamp),
 202                int (*set_dscp_cb)(int fd, uint8_t dscp),
 203                char *unlink_path, struct pstream **pstreamp)
 204 {
 205     struct fd_pstream *ps = xmalloc(sizeof *ps);
 206     pstream_init(&ps->pstream, &fd_pstream_class, name);
 207     ps->fd = fd;
 208     ps->accept_cb = accept_cb;
 209     ps->set_dscp_cb = set_dscp_cb;
 210     ps->unlink_path = unlink_path;
 211     *pstreamp = &ps->pstream;
 212     return 0;
 213 }
 214
 215 static void
 216 pfd_close(struct pstream *pstream)
 217 {
 218     struct fd_pstream *ps = fd_pstream_cast(pstream);
 219     close(ps->fd);
 220     maybe_unlink_and_free(ps->unlink_path);
 221     free(ps);
 222 }
 223
 224 static int
 225 pfd_accept(struct pstream *pstream, struct stream **new_streamp)
 226 {
 227     struct fd_pstream *ps = fd_pstream_cast(pstream);
 228     struct sockaddr_storage ss;
 229     socklen_t ss_len = sizeof ss;
 230     int new_fd;
 231     int retval;
 232
 233     new_fd = accept(ps->fd, (struct sockaddr *) &ss, &ss_len);
 234     if (new_fd < 0) {
 235         retval = errno;
 236         if (retval != EAGAIN) {
 237             VLOG_DBG_RL(&rl, "accept: %s", strerror(retval));
 238         }
 239         return retval;
 240     }
 241
 242     retval = set_nonblocking(new_fd);
 243     if (retval) {
 244         close(new_fd);
 245         return retval;
 246     }
 247
 248     return ps->accept_cb(new_fd, (const struct sockaddr *) &ss, ss_len,
 249                          new_streamp);
 250 }
 251
 252 static void
 253 pfd_wait(struct pstream *pstream)
 254 {
 255     struct fd_pstream *ps = fd_pstream_cast(pstream);
 256     poll_fd_wait(ps->fd, POLLIN);
 257 }
 258
 259 static int
 260 pfd_set_dscp(struct pstream *pstream, uint8_t dscp)
 261 {
 262     struct fd_pstream *ps = fd_pstream_cast(pstream);
 263     if (ps->set_dscp_cb) {
 264         return ps->set_dscp_cb(ps->fd, dscp);
 265     }
 266     return 0;
 267 }
 268
 269 static struct pstream_class fd_pstream_class = {
 270     "pstream",
 271     false,
 272     NULL,
 273     pfd_close,
 274     pfd_accept,
 275     pfd_wait,
 276     pfd_set_dscp,
 277 };
 278 \f
 279 /* Helper functions. */
 280 static void
 281 maybe_unlink_and_free(char *path)
 282 {
 283     if (path) {
 284         fatal_signal_unlink_file_now(path);
 285         free(path);
 286     }
 287 }