lib/stream-fd.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2012, 2013 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 "poll-loop.h"
  28 #include "socket-util.h"
  29 #include "util.h"
  30 #include "stream-provider.h"
  31 #include "stream.h"
  32 #include "vlog.h"
  33
  34 VLOG_DEFINE_THIS_MODULE(stream_fd);
  35
  36 /* Active file descriptor stream. */
  37
  38 struct stream_fd
  39 {
  40     struct stream stream;
  41     int fd;
  42 };
  43
  44 static const struct stream_class stream_fd_class;
  45
  46 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
  47
  48 static void maybe_unlink_and_free(char *path);
  49
  50 /* Creates a new stream named 'name' that will send and receive data on 'fd'
  51  * and stores a pointer to the stream in '*streamp'.  Initial connection status
  52  * 'connect_status' is interpreted as described for stream_init().
  53  *
  54  * Returns 0 if successful, otherwise a positive errno value.  (The current
  55  * implementation never fails.) */
  56 int
  57 new_fd_stream(const char *name, int fd, int connect_status,
  58               struct stream **streamp)
  59 {
  60     struct stream_fd *s;
  61
  62     s = xmalloc(sizeof *s);
  63     stream_init(&s->stream, &stream_fd_class, connect_status, name);
  64     s->fd = fd;
  65     *streamp = &s->stream;
  66     return 0;
  67 }
  68
  69 static struct stream_fd *
  70 stream_fd_cast(struct stream *stream)
  71 {
  72     stream_assert_class(stream, &stream_fd_class);
  73     return CONTAINER_OF(stream, struct stream_fd, stream);
  74 }
  75
  76 static void
  77 fd_close(struct stream *stream)
  78 {
  79     struct stream_fd *s = stream_fd_cast(stream);
  80     close(s->fd);
  81     free(s);
  82 }
  83
  84 static int
  85 fd_connect(struct stream *stream)
  86 {
  87     struct stream_fd *s = stream_fd_cast(stream);
  88     return check_connection_completion(s->fd);
  89 }
  90
  91 static ssize_t
  92 fd_recv(struct stream *stream, void *buffer, size_t n)
  93 {
  94     struct stream_fd *s = stream_fd_cast(stream);
  95     ssize_t retval;
  96
  97     retval = read(s->fd, buffer, n);
  98     return retval >= 0 ? retval : -errno;
  99 }
 100
 101 static ssize_t
 102 fd_send(struct stream *stream, const void *buffer, size_t n)
 103 {
 104     struct stream_fd *s = stream_fd_cast(stream);
 105     ssize_t retval;
 106
 107     retval = write(s->fd, buffer, n);
 108     return (retval > 0 ? retval
 109             : retval == 0 ? -EAGAIN
 110             : -errno);
 111 }
 112
 113 static void
 114 fd_wait(struct stream *stream, enum stream_wait_type wait)
 115 {
 116     struct stream_fd *s = stream_fd_cast(stream);
 117     switch (wait) {
 118     case STREAM_CONNECT:
 119     case STREAM_SEND:
 120         poll_fd_wait(s->fd, POLLOUT);
 121         break;
 122
 123     case STREAM_RECV:
 124         poll_fd_wait(s->fd, POLLIN);
 125         break;
 126
 127     default:
 128         NOT_REACHED();
 129     }
 130 }
 131
 132 static const struct stream_class stream_fd_class = {
 133     "fd",                       /* name */
 134     false,                      /* needs_probes */
 135     NULL,                       /* open */
 136     fd_close,                   /* close */
 137     fd_connect,                 /* connect */
 138     fd_recv,                    /* recv */
 139     fd_send,                    /* send */
 140     NULL,                       /* run */
 141     NULL,                       /* run_wait */
 142     fd_wait,                    /* wait */
 143 };
 144 \f
 145 /* Passive file descriptor stream. */
 146
 147 struct fd_pstream
 148 {
 149     struct pstream pstream;
 150     int fd;
 151     int (*accept_cb)(int fd, const struct sockaddr *, size_t sa_len,
 152                      struct stream **);
 153     int (*set_dscp_cb)(int fd, uint8_t dscp);
 154     char *unlink_path;
 155 };
 156
 157 static const struct pstream_class fd_pstream_class;
 158
 159 static struct fd_pstream *
 160 fd_pstream_cast(struct pstream *pstream)
 161 {
 162     pstream_assert_class(pstream, &fd_pstream_class);
 163     return CONTAINER_OF(pstream, struct fd_pstream, pstream);
 164 }
 165
 166 /* Creates a new pstream named 'name' that will accept new socket connections
 167  * on 'fd' and stores a pointer to the stream in '*pstreamp'.
 168  *
 169  * When a connection has been accepted, 'accept_cb' will be called with the new
 170  * socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
 171  * accept_cb must return 0 if the connection is successful, in which case it
 172  * must initialize '*streamp' to the new stream, or a positive errno value on
 173  * error.  In either case accept_cb takes ownership of the 'fd' passed in.
 174  *
 175  * When '*pstreamp' is closed, then 'unlink_path' (if nonnull) will be passed
 176  * to fatal_signal_unlink_file_now() and freed with free().
 177  *
 178  * Returns 0 if successful, otherwise a positive errno value.  (The current
 179  * implementation never fails.) */
 180 int
 181 new_fd_pstream(const char *name, int fd,
 182                int (*accept_cb)(int fd, const struct sockaddr *sa,
 183                                 size_t sa_len, struct stream **streamp),
 184                int (*set_dscp_cb)(int fd, uint8_t dscp),
 185                char *unlink_path, struct pstream **pstreamp)
 186 {
 187     struct fd_pstream *ps = xmalloc(sizeof *ps);
 188     pstream_init(&ps->pstream, &fd_pstream_class, name);
 189     ps->fd = fd;
 190     ps->accept_cb = accept_cb;
 191     ps->set_dscp_cb = set_dscp_cb;
 192     ps->unlink_path = unlink_path;
 193     *pstreamp = &ps->pstream;
 194     return 0;
 195 }
 196
 197 static void
 198 pfd_close(struct pstream *pstream)
 199 {
 200     struct fd_pstream *ps = fd_pstream_cast(pstream);
 201     close(ps->fd);
 202     maybe_unlink_and_free(ps->unlink_path);
 203     free(ps);
 204 }
 205
 206 static int
 207 pfd_accept(struct pstream *pstream, struct stream **new_streamp)
 208 {
 209     struct fd_pstream *ps = fd_pstream_cast(pstream);
 210     struct sockaddr_storage ss;
 211     socklen_t ss_len = sizeof ss;
 212     int new_fd;
 213     int retval;
 214
 215     new_fd = accept(ps->fd, (struct sockaddr *) &ss, &ss_len);
 216     if (new_fd < 0) {
 217         retval = errno;
 218         if (retval != EAGAIN) {
 219             VLOG_DBG_RL(&rl, "accept: %s", ovs_strerror(retval));
 220         }
 221         return retval;
 222     }
 223
 224     retval = set_nonblocking(new_fd);
 225     if (retval) {
 226         close(new_fd);
 227         return retval;
 228     }
 229
 230     return ps->accept_cb(new_fd, (const struct sockaddr *) &ss, ss_len,
 231                          new_streamp);
 232 }
 233
 234 static void
 235 pfd_wait(struct pstream *pstream)
 236 {
 237     struct fd_pstream *ps = fd_pstream_cast(pstream);
 238     poll_fd_wait(ps->fd, POLLIN);
 239 }
 240
 241 static int
 242 pfd_set_dscp(struct pstream *pstream, uint8_t dscp)
 243 {
 244     struct fd_pstream *ps = fd_pstream_cast(pstream);
 245     if (ps->set_dscp_cb) {
 246         return ps->set_dscp_cb(ps->fd, dscp);
 247     }
 248     return 0;
 249 }
 250
 251 static const struct pstream_class fd_pstream_class = {
 252     "pstream",
 253     false,
 254     NULL,
 255     pfd_close,
 256     pfd_accept,
 257     pfd_wait,
 258     pfd_set_dscp,
 259 };
 260 \f
 261 /* Helper functions. */
 262 static void
 263 maybe_unlink_and_free(char *path)
 264 {
 265     if (path) {
 266         fatal_signal_unlink_file_now(path);
 267         free(path);
 268     }
 269 }