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openvswitch/lib/stream-fd.c
Ben Pfaff cc01d0bb79 Implement stress option framework.
Stress options allow developers testing Open vSwitch to trigger behavior
that otherwise would occur only in corner cases.  Developers and testers
can thereby more easily discover bugs that would otherwise manifest only
rarely or nondeterministically.  Stress options may cause surprising
behavior even when they do not actually reveal bugs, so they should only be
enabled as part of testing Open vSwitch.

This commit implements the framework and adds a few example stress options.

This commit started from code written by Andrew Lambeth.

Suggested-by: Henrik Amren <henrik@nicira.com>
CC: Andrew Lambeth <wal@nicira.com>
2010-11-30 13:44:01 -08:00

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/*
* Copyright (c) 2008, 2009, 2010 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "stream-fd.h"
#include <assert.h>
#include <errno.h>
#include <poll.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include "fatal-signal.h"
#include "leak-checker.h"
#include "poll-loop.h"
#include "socket-util.h"
#include "stress.h"
#include "util.h"
#include "stream-provider.h"
#include "stream.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(stream_fd);
/* Active file descriptor stream. */
struct stream_fd
{
struct stream stream;
int fd;
char *unlink_path;
};
static struct stream_class stream_fd_class;
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
static void maybe_unlink_and_free(char *path);
/* Creates a new stream named 'name' that will send and receive data on 'fd'
* and stores a pointer to the stream in '*streamp'. Initial connection status
* 'connect_status' is interpreted as described for stream_init().
*
* When '*streamp' is closed, then 'unlink_path' (if nonnull) will be passed to
* fatal_signal_unlink_file_now() and then freed with free().
*
* Returns 0 if successful, otherwise a positive errno value. (The current
* implementation never fails.) */
int
new_fd_stream(const char *name, int fd, int connect_status,
char *unlink_path, struct stream **streamp)
{
struct stream_fd *s;
s = xmalloc(sizeof *s);
stream_init(&s->stream, &stream_fd_class, connect_status, name);
s->fd = fd;
s->unlink_path = unlink_path;
*streamp = &s->stream;
return 0;
}
static struct stream_fd *
stream_fd_cast(struct stream *stream)
{
stream_assert_class(stream, &stream_fd_class);
return CONTAINER_OF(stream, struct stream_fd, stream);
}
static void
fd_close(struct stream *stream)
{
struct stream_fd *s = stream_fd_cast(stream);
close(s->fd);
maybe_unlink_and_free(s->unlink_path);
free(s);
}
static int
fd_connect(struct stream *stream)
{
struct stream_fd *s = stream_fd_cast(stream);
return check_connection_completion(s->fd);
}
STRESS_OPTION(
stream_flaky_recv, "simulate failure of fd stream recvs",
100, 0, -1, 0);
static ssize_t
fd_recv(struct stream *stream, void *buffer, size_t n)
{
struct stream_fd *s = stream_fd_cast(stream);
ssize_t retval;
if (STRESS(stream_flaky_recv)) {
return -EIO;
}
retval = read(s->fd, buffer, n);
return retval >= 0 ? retval : -errno;
}
STRESS_OPTION(
stream_flaky_send, "simulate failure of fd stream sends",
100, 0, -1, 0);
static ssize_t
fd_send(struct stream *stream, const void *buffer, size_t n)
{
struct stream_fd *s = stream_fd_cast(stream);
ssize_t retval;
if (STRESS(stream_flaky_send)) {
return -EIO;
}
retval = write(s->fd, buffer, n);
return (retval > 0 ? retval
: retval == 0 ? -EAGAIN
: -errno);
}
static void
fd_wait(struct stream *stream, enum stream_wait_type wait)
{
struct stream_fd *s = stream_fd_cast(stream);
switch (wait) {
case STREAM_CONNECT:
case STREAM_SEND:
poll_fd_wait(s->fd, POLLOUT);
break;
case STREAM_RECV:
poll_fd_wait(s->fd, POLLIN);
break;
default:
NOT_REACHED();
}
}
static struct stream_class stream_fd_class = {
"fd", /* name */
NULL, /* open */
fd_close, /* close */
fd_connect, /* connect */
fd_recv, /* recv */
fd_send, /* send */
NULL, /* run */
NULL, /* run_wait */
fd_wait, /* wait */
};
/* Passive file descriptor stream. */
struct fd_pstream
{
struct pstream pstream;
int fd;
int (*accept_cb)(int fd, const struct sockaddr *, size_t sa_len,
struct stream **);
char *unlink_path;
};
static struct pstream_class fd_pstream_class;
static struct fd_pstream *
fd_pstream_cast(struct pstream *pstream)
{
pstream_assert_class(pstream, &fd_pstream_class);
return CONTAINER_OF(pstream, struct fd_pstream, pstream);
}
/* Creates a new pstream named 'name' that will accept new socket connections
* on 'fd' and stores a pointer to the stream in '*pstreamp'.
*
* When a connection has been accepted, 'accept_cb' will be called with the new
* socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
* accept_cb must return 0 if the connection is successful, in which case it
* must initialize '*streamp' to the new stream, or a positive errno value on
* error. In either case accept_cb takes ownership of the 'fd' passed in.
*
* When '*pstreamp' is closed, then 'unlink_path' (if nonnull) will be passed
* to fatal_signal_unlink_file_now() and freed with free().
*
* Returns 0 if successful, otherwise a positive errno value. (The current
* implementation never fails.) */
int
new_fd_pstream(const char *name, int fd,
int (*accept_cb)(int fd, const struct sockaddr *sa,
size_t sa_len, struct stream **streamp),
char *unlink_path, struct pstream **pstreamp)
{
struct fd_pstream *ps = xmalloc(sizeof *ps);
pstream_init(&ps->pstream, &fd_pstream_class, name);
ps->fd = fd;
ps->accept_cb = accept_cb;
ps->unlink_path = unlink_path;
*pstreamp = &ps->pstream;
return 0;
}
static void
pfd_close(struct pstream *pstream)
{
struct fd_pstream *ps = fd_pstream_cast(pstream);
close(ps->fd);
maybe_unlink_and_free(ps->unlink_path);
free(ps);
}
static int
pfd_accept(struct pstream *pstream, struct stream **new_streamp)
{
struct fd_pstream *ps = fd_pstream_cast(pstream);
struct sockaddr_storage ss;
socklen_t ss_len = sizeof ss;
int new_fd;
int retval;
new_fd = accept(ps->fd, (struct sockaddr *) &ss, &ss_len);
if (new_fd < 0) {
retval = errno;
if (retval != EAGAIN) {
VLOG_DBG_RL(&rl, "accept: %s", strerror(retval));
}
return retval;
}
retval = set_nonblocking(new_fd);
if (retval) {
close(new_fd);
return retval;
}
return ps->accept_cb(new_fd, (const struct sockaddr *) &ss, ss_len,
new_streamp);
}
static void
pfd_wait(struct pstream *pstream)
{
struct fd_pstream *ps = fd_pstream_cast(pstream);
poll_fd_wait(ps->fd, POLLIN);
}
static struct pstream_class fd_pstream_class = {
"pstream",
NULL,
pfd_close,
pfd_accept,
pfd_wait
};
/* Helper functions. */
static void
maybe_unlink_and_free(char *path)
{
if (path) {
fatal_signal_unlink_file_now(path);
free(path);
}
}