libvirt/src/fdstream.c
Cole Robinson a5481546d6 fdstream: don't raise error on SIGPIPE if abort requested
The iohelper dies on SIGPIPE if the stream is closed before all data
is processed. IMO this should be an error condition for virStreamFinish
according to docs like:

  * This method is a synchronization point for all asynchronous
  * errors, so if this returns a success code the application can
  * be sure that all data has been successfully processed.

However for virStreamAbort, not so much:

  * Request that the in progress data transfer be cancelled
  * abnormally before the end of the stream has been reached.
  * For output streams this can be used to inform the driver
  * that the stream is being terminated early. For input
  * streams this can be used to inform the driver that it
  * should stop sending data.

Without this, virStreamAbort will realistically always error for
active streams like domain console. So, treat the SIGPIPE case
as non-fatal if abort is requested.

Note, this will only affect an explicit user requested abort. An
abnormal abort, like from a server error, always raises an error
in the daemon.
2016-05-02 10:13:05 -04:00

834 lines
22 KiB
C

/*
* fdstream.c: generic streams impl for file descriptors
*
* Copyright (C) 2009-2012, 2014 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/wait.h>
#if HAVE_SYS_UN_H
# include <sys/un.h>
#endif
#include <netinet/in.h>
#include <termios.h>
#include "fdstream.h"
#include "virerror.h"
#include "datatypes.h"
#include "virlog.h"
#include "viralloc.h"
#include "virutil.h"
#include "virfile.h"
#include "configmake.h"
#include "virstring.h"
#include "virtime.h"
#include "virprocess.h"
#define VIR_FROM_THIS VIR_FROM_STREAMS
VIR_LOG_INIT("fdstream");
/* Tunnelled migration stream support */
struct virFDStreamData {
int fd;
int errfd;
virCommandPtr cmd;
unsigned long long offset;
unsigned long long length;
int watch;
int events; /* events the stream callback is subscribed for */
bool cbRemoved;
bool dispatching;
bool closed;
virStreamEventCallback cb;
void *opaque;
virFreeCallback ff;
/* don't call the abort callback more than once */
bool abortCallbackCalled;
bool abortCallbackDispatching;
/* internal callback, as the regular one (from generic streams) gets
* eaten up by the server stream driver */
virFDStreamInternalCloseCb icbCb;
virFDStreamInternalCloseCbFreeOpaque icbFreeOpaque;
void *icbOpaque;
virMutex lock;
};
static int virFDStreamRemoveCallback(virStreamPtr stream)
{
struct virFDStreamData *fdst = stream->privateData;
int ret = -1;
if (!fdst) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream is not open"));
return -1;
}
virMutexLock(&fdst->lock);
if (fdst->watch == 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream does not have a callback registered"));
goto cleanup;
}
virEventRemoveHandle(fdst->watch);
if (fdst->dispatching)
fdst->cbRemoved = true;
else if (fdst->ff)
(fdst->ff)(fdst->opaque);
fdst->watch = 0;
fdst->ff = NULL;
fdst->cb = NULL;
fdst->events = 0;
fdst->opaque = NULL;
ret = 0;
cleanup:
virMutexUnlock(&fdst->lock);
return ret;
}
static int virFDStreamUpdateCallback(virStreamPtr stream, int events)
{
struct virFDStreamData *fdst = stream->privateData;
int ret = -1;
if (!fdst) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream is not open"));
return -1;
}
virMutexLock(&fdst->lock);
if (fdst->watch == 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream does not have a callback registered"));
goto cleanup;
}
virEventUpdateHandle(fdst->watch, events);
fdst->events = events;
ret = 0;
cleanup:
virMutexUnlock(&fdst->lock);
return ret;
}
static void virFDStreamEvent(int watch ATTRIBUTE_UNUSED,
int fd ATTRIBUTE_UNUSED,
int events,
void *opaque)
{
virStreamPtr stream = opaque;
struct virFDStreamData *fdst = stream->privateData;
virStreamEventCallback cb;
void *cbopaque;
virFreeCallback ff;
bool closed;
if (!fdst)
return;
virMutexLock(&fdst->lock);
if (!fdst->cb) {
virMutexUnlock(&fdst->lock);
return;
}
cb = fdst->cb;
cbopaque = fdst->opaque;
ff = fdst->ff;
fdst->dispatching = true;
virMutexUnlock(&fdst->lock);
cb(stream, events, cbopaque);
virMutexLock(&fdst->lock);
fdst->dispatching = false;
if (fdst->cbRemoved && ff)
(ff)(cbopaque);
closed = fdst->closed;
virMutexUnlock(&fdst->lock);
if (closed) {
virMutexDestroy(&fdst->lock);
VIR_FREE(fdst);
}
}
static void virFDStreamCallbackFree(void *opaque)
{
virObjectUnref(opaque);
}
static int
virFDStreamAddCallback(virStreamPtr st,
int events,
virStreamEventCallback cb,
void *opaque,
virFreeCallback ff)
{
struct virFDStreamData *fdst = st->privateData;
int ret = -1;
if (!fdst) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream is not open"));
return -1;
}
virMutexLock(&fdst->lock);
if (fdst->watch != 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream already has a callback registered"));
goto cleanup;
}
if ((fdst->watch = virEventAddHandle(fdst->fd,
events,
virFDStreamEvent,
st,
virFDStreamCallbackFree)) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("cannot register file watch on stream"));
goto cleanup;
}
fdst->cbRemoved = false;
fdst->cb = cb;
fdst->opaque = opaque;
fdst->ff = ff;
fdst->events = events;
fdst->abortCallbackCalled = false;
virStreamRef(st);
ret = 0;
cleanup:
virMutexUnlock(&fdst->lock);
return ret;
}
static int
virFDStreamCloseCommand(struct virFDStreamData *fdst, bool streamAbort)
{
char buf[1024];
ssize_t len;
int status;
int ret = -1;
if (!fdst->cmd)
return 0;
if ((len = saferead(fdst->errfd, buf, sizeof(buf)-1)) < 0)
buf[0] = '\0';
else
buf[len] = '\0';
virCommandRawStatus(fdst->cmd);
if (virCommandWait(fdst->cmd, &status) < 0)
goto cleanup;
if (status != 0) {
if (buf[0] != '\0') {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", buf);
} else if (WIFSIGNALED(status) && WTERMSIG(status) == SIGPIPE) {
if (streamAbort) {
/* Explicit abort request means the caller doesn't care
if there's data left over, so skip the error */
goto out;
}
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("I/O helper exited "
"before all data was processed"));
} else {
char *str = virProcessTranslateStatus(status);
virReportError(VIR_ERR_INTERNAL_ERROR,
_("I/O helper exited with %s"),
NULLSTR(str));
VIR_FREE(str);
}
goto cleanup;
}
out:
ret = 0;
cleanup:
virCommandFree(fdst->cmd);
fdst->cmd = NULL;
return ret;
}
static int
virFDStreamCloseInt(virStreamPtr st, bool streamAbort)
{
struct virFDStreamData *fdst;
virStreamEventCallback cb;
void *opaque;
int ret;
VIR_DEBUG("st=%p", st);
if (!st || !(fdst = st->privateData) || fdst->abortCallbackDispatching)
return 0;
virMutexLock(&fdst->lock);
/* aborting the stream, ensure the callback is called if it's
* registered for stream error event */
if (streamAbort &&
fdst->cb &&
(fdst->events & (VIR_STREAM_EVENT_READABLE |
VIR_STREAM_EVENT_WRITABLE))) {
/* don't enter this function accidentally from the callback again */
if (fdst->abortCallbackCalled) {
virMutexUnlock(&fdst->lock);
return 0;
}
fdst->abortCallbackCalled = true;
fdst->abortCallbackDispatching = true;
/* cache the pointers */
cb = fdst->cb;
opaque = fdst->opaque;
virMutexUnlock(&fdst->lock);
/* call failure callback, poll reports nothing on closed fd */
(cb)(st, VIR_STREAM_EVENT_ERROR, opaque);
virMutexLock(&fdst->lock);
fdst->abortCallbackDispatching = false;
}
/* mutex locked */
ret = VIR_CLOSE(fdst->fd);
if (virFDStreamCloseCommand(fdst, streamAbort) < 0)
ret = -1;
if (VIR_CLOSE(fdst->errfd) < 0)
VIR_DEBUG("ignoring failed close on fd %d", fdst->errfd);
st->privateData = NULL;
/* call the internal stream closing callback */
if (fdst->icbCb) {
/* the mutex is not accessible anymore, as private data is null */
(fdst->icbCb)(st, fdst->icbOpaque);
if (fdst->icbFreeOpaque)
(fdst->icbFreeOpaque)(fdst->icbOpaque);
}
if (fdst->dispatching) {
fdst->closed = true;
virMutexUnlock(&fdst->lock);
} else {
virMutexUnlock(&fdst->lock);
virMutexDestroy(&fdst->lock);
VIR_FREE(fdst);
}
return ret;
}
static int
virFDStreamClose(virStreamPtr st)
{
return virFDStreamCloseInt(st, false);
}
static int
virFDStreamAbort(virStreamPtr st)
{
return virFDStreamCloseInt(st, true);
}
static int virFDStreamWrite(virStreamPtr st, const char *bytes, size_t nbytes)
{
struct virFDStreamData *fdst = st->privateData;
int ret;
if (nbytes > INT_MAX) {
virReportSystemError(ERANGE, "%s",
_("Too many bytes to write to stream"));
return -1;
}
if (!fdst) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream is not open"));
return -1;
}
virMutexLock(&fdst->lock);
if (fdst->length) {
if (fdst->length == fdst->offset) {
virReportSystemError(ENOSPC, "%s",
_("cannot write to stream"));
virMutexUnlock(&fdst->lock);
return -1;
}
if ((fdst->length - fdst->offset) < nbytes)
nbytes = fdst->length - fdst->offset;
}
retry:
ret = write(fdst->fd, bytes, nbytes);
if (ret < 0) {
VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (errno == EAGAIN || errno == EWOULDBLOCK) {
VIR_WARNINGS_RESET
ret = -2;
} else if (errno == EINTR) {
goto retry;
} else {
ret = -1;
virReportSystemError(errno, "%s",
_("cannot write to stream"));
}
} else if (fdst->length) {
fdst->offset += ret;
}
virMutexUnlock(&fdst->lock);
return ret;
}
static int virFDStreamRead(virStreamPtr st, char *bytes, size_t nbytes)
{
struct virFDStreamData *fdst = st->privateData;
int ret;
if (nbytes > INT_MAX) {
virReportSystemError(ERANGE, "%s",
_("Too many bytes to read from stream"));
return -1;
}
if (!fdst) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("stream is not open"));
return -1;
}
virMutexLock(&fdst->lock);
if (fdst->length) {
if (fdst->length == fdst->offset) {
virMutexUnlock(&fdst->lock);
return 0;
}
if ((fdst->length - fdst->offset) < nbytes)
nbytes = fdst->length - fdst->offset;
}
retry:
ret = read(fdst->fd, bytes, nbytes);
if (ret < 0) {
VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (errno == EAGAIN || errno == EWOULDBLOCK) {
VIR_WARNINGS_RESET
ret = -2;
} else if (errno == EINTR) {
goto retry;
} else {
ret = -1;
virReportSystemError(errno, "%s",
_("cannot read from stream"));
}
} else if (fdst->length) {
fdst->offset += ret;
}
virMutexUnlock(&fdst->lock);
return ret;
}
static virStreamDriver virFDStreamDrv = {
.streamSend = virFDStreamWrite,
.streamRecv = virFDStreamRead,
.streamFinish = virFDStreamClose,
.streamAbort = virFDStreamAbort,
.streamEventAddCallback = virFDStreamAddCallback,
.streamEventUpdateCallback = virFDStreamUpdateCallback,
.streamEventRemoveCallback = virFDStreamRemoveCallback
};
static int virFDStreamOpenInternal(virStreamPtr st,
int fd,
virCommandPtr cmd,
int errfd,
unsigned long long length)
{
struct virFDStreamData *fdst;
VIR_DEBUG("st=%p fd=%d cmd=%p errfd=%d length=%llu",
st, fd, cmd, errfd, length);
if ((st->flags & VIR_STREAM_NONBLOCK) &&
virSetNonBlock(fd) < 0) {
virReportSystemError(errno, "%s", _("Unable to set non-blocking mode"));
return -1;
}
if (VIR_ALLOC(fdst) < 0)
return -1;
fdst->fd = fd;
fdst->cmd = cmd;
fdst->errfd = errfd;
fdst->length = length;
if (virMutexInit(&fdst->lock) < 0) {
VIR_FREE(fdst);
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Unable to initialize mutex"));
return -1;
}
st->driver = &virFDStreamDrv;
st->privateData = fdst;
return 0;
}
int virFDStreamOpen(virStreamPtr st,
int fd)
{
return virFDStreamOpenInternal(st, fd, NULL, -1, 0);
}
#if HAVE_SYS_UN_H
int virFDStreamConnectUNIX(virStreamPtr st,
const char *path,
bool abstract)
{
struct sockaddr_un sa;
virTimeBackOffVar timeout;
int ret;
int fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd < 0) {
virReportSystemError(errno, "%s", _("Unable to open UNIX socket"));
goto error;
}
memset(&sa, 0, sizeof(sa));
sa.sun_family = AF_UNIX;
if (abstract) {
if (virStrcpy(sa.sun_path+1, path, sizeof(sa.sun_path)-1) == NULL)
goto error;
sa.sun_path[0] = '\0';
} else {
if (virStrcpy(sa.sun_path, path, sizeof(sa.sun_path)) == NULL)
goto error;
}
if (virTimeBackOffStart(&timeout, 1, 3*1000 /* ms */) < 0)
goto error;
while (virTimeBackOffWait(&timeout)) {
ret = connect(fd, (struct sockaddr *)&sa, sizeof(sa));
if (ret == 0)
break;
if (errno == ENOENT || errno == ECONNREFUSED) {
/* ENOENT : Socket may not have shown up yet
* ECONNREFUSED : Leftover socket hasn't been removed yet */
continue;
}
goto error;
}
if (virFDStreamOpenInternal(st, fd, NULL, -1, 0) < 0)
goto error;
return 0;
error:
VIR_FORCE_CLOSE(fd);
return -1;
}
#else
int virFDStreamConnectUNIX(virStreamPtr st ATTRIBUTE_UNUSED,
const char *path ATTRIBUTE_UNUSED,
bool abstract ATTRIBUTE_UNUSED)
{
virReportSystemError(ENOSYS, "%s",
_("UNIX domain sockets are not supported on this platform"));
return -1;
}
#endif
static int
virFDStreamOpenFileInternal(virStreamPtr st,
const char *path,
unsigned long long offset,
unsigned long long length,
int oflags,
int mode,
bool forceIOHelper)
{
int fd = -1;
int childfd = -1;
struct stat sb;
virCommandPtr cmd = NULL;
int errfd = -1;
char *iohelper_path = NULL;
VIR_DEBUG("st=%p path=%s oflags=%x offset=%llu length=%llu mode=%o",
st, path, oflags, offset, length, mode);
oflags |= O_NOCTTY | O_BINARY;
if (oflags & O_CREAT)
fd = open(path, oflags, mode);
else
fd = open(path, oflags);
if (fd < 0) {
virReportSystemError(errno,
_("Unable to open stream for '%s'"),
path);
return -1;
}
if (fstat(fd, &sb) < 0) {
virReportSystemError(errno,
_("Unable to access stream for '%s'"),
path);
goto error;
}
if (offset &&
lseek(fd, offset, SEEK_SET) < 0) {
virReportSystemError(errno,
_("Unable to seek %s to %llu"),
path, offset);
goto error;
}
/* Thanks to the POSIX i/o model, we can't reliably get
* non-blocking I/O on block devs/regular files. To
* support those we need to fork a helper process to do
* the I/O so we just have a fifo. Or use AIO :-(
*/
if ((st->flags & VIR_STREAM_NONBLOCK) &&
((!S_ISCHR(sb.st_mode) &&
!S_ISFIFO(sb.st_mode)) || forceIOHelper)) {
int fds[2] = { -1, -1 };
if ((oflags & O_ACCMODE) == O_RDWR) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("%s: Cannot request read and write flags together"),
path);
goto error;
}
if (pipe(fds) < 0) {
virReportSystemError(errno, "%s",
_("Unable to create pipe"));
goto error;
}
if (!(iohelper_path = virFileFindResource("libvirt_iohelper",
abs_topbuilddir "/src",
LIBEXECDIR)))
goto error;
cmd = virCommandNewArgList(iohelper_path,
path,
NULL);
VIR_FREE(iohelper_path);
virCommandAddArgFormat(cmd, "%llu", length);
virCommandPassFD(cmd, fd,
VIR_COMMAND_PASS_FD_CLOSE_PARENT);
virCommandAddArgFormat(cmd, "%d", fd);
if ((oflags & O_ACCMODE) == O_RDONLY) {
childfd = fds[1];
fd = fds[0];
virCommandSetOutputFD(cmd, &childfd);
} else {
childfd = fds[0];
fd = fds[1];
virCommandSetInputFD(cmd, childfd);
}
virCommandSetErrorFD(cmd, &errfd);
if (virCommandRunAsync(cmd, NULL) < 0)
goto error;
VIR_FORCE_CLOSE(childfd);
}
if (virFDStreamOpenInternal(st, fd, cmd, errfd, length) < 0)
goto error;
return 0;
error:
virCommandFree(cmd);
VIR_FORCE_CLOSE(fd);
VIR_FORCE_CLOSE(childfd);
VIR_FORCE_CLOSE(errfd);
VIR_FREE(iohelper_path);
if (oflags & O_CREAT)
unlink(path);
return -1;
}
int virFDStreamOpenFile(virStreamPtr st,
const char *path,
unsigned long long offset,
unsigned long long length,
int oflags)
{
if (oflags & O_CREAT) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Attempt to create %s without specifying mode"),
path);
return -1;
}
return virFDStreamOpenFileInternal(st, path,
offset, length,
oflags, 0, false);
}
int virFDStreamCreateFile(virStreamPtr st,
const char *path,
unsigned long long offset,
unsigned long long length,
int oflags,
mode_t mode)
{
return virFDStreamOpenFileInternal(st, path,
offset, length,
oflags | O_CREAT, mode,
false);
}
#ifdef HAVE_CFMAKERAW
int virFDStreamOpenPTY(virStreamPtr st,
const char *path,
unsigned long long offset,
unsigned long long length,
int oflags)
{
struct virFDStreamData *fdst = NULL;
struct termios rawattr;
if (virFDStreamOpenFileInternal(st, path,
offset, length,
oflags | O_CREAT, 0,
false) < 0)
return -1;
fdst = st->privateData;
if (tcgetattr(fdst->fd, &rawattr) < 0) {
virReportSystemError(errno,
_("unable to get tty attributes: %s"),
path);
goto cleanup;
}
cfmakeraw(&rawattr);
if (tcsetattr(fdst->fd, TCSANOW, &rawattr) < 0) {
virReportSystemError(errno,
_("unable to set tty attributes: %s"),
path);
goto cleanup;
}
return 0;
cleanup:
virFDStreamClose(st);
return -1;
}
#else /* !HAVE_CFMAKERAW */
int virFDStreamOpenPTY(virStreamPtr st,
const char *path,
unsigned long long offset,
unsigned long long length,
int oflags)
{
return virFDStreamOpenFileInternal(st, path,
offset, length,
oflags | O_CREAT, 0,
false);
}
#endif /* !HAVE_CFMAKERAW */
int virFDStreamOpenBlockDevice(virStreamPtr st,
const char *path,
unsigned long long offset,
unsigned long long length,
int oflags)
{
return virFDStreamOpenFileInternal(st, path,
offset, length,
oflags, 0, true);
}
int virFDStreamSetInternalCloseCb(virStreamPtr st,
virFDStreamInternalCloseCb cb,
void *opaque,
virFDStreamInternalCloseCbFreeOpaque fcb)
{
struct virFDStreamData *fdst = st->privateData;
virMutexLock(&fdst->lock);
if (fdst->icbFreeOpaque)
(fdst->icbFreeOpaque)(fdst->icbOpaque);
fdst->icbCb = cb;
fdst->icbOpaque = opaque;
fdst->icbFreeOpaque = fcb;
virMutexUnlock(&fdst->lock);
return 0;
}