/*
* fdstream.c: generic streams impl for file descriptors
*
* Copyright (C) 2009-2012 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 "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"
#define VIR_FROM_THIS VIR_FROM_STREAMS
/* 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 const char *iohelper_path = LIBEXECDIR "/libvirt_iohelper";
void virFDStreamSetIOHelper(const char *path)
{
if (path == NULL)
iohelper_path = LIBEXECDIR "/libvirt_iohelper";
else
iohelper_path = path;
}
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)
{
virStreamPtr st = opaque;
virStreamFree(st);
}
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
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 (fdst->cmd) {
char buf[1024];
ssize_t len;
int status;
if ((len = saferead(fdst->errfd, buf, sizeof(buf)-1)) < 0)
buf[0] = '\0';
else
buf[len] = '\0';
if (virCommandWait(fdst->cmd, &status) < 0) {
ret = -1;
} else if (status != 0) {
if (buf[0] == '\0') {
if (WIFEXITED(status)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("I/O helper exited with status %d"),
WEXITSTATUS(status));
} else {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("I/O helper exited abnormally"));
}
} else {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
buf);
}
ret = -1;
}
virCommandFree(fdst->cmd);
fdst->cmd = NULL;
}
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) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
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) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
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)
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;
size_t i = 0;
int timeout = 3;
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;
}
do {
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;
} while ((++i <= timeout*5) && (usleep(.2 * 1000000) <= 0));
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)
{
int fd = -1;
int childfd = -1;
struct stat sb;
virCommandPtr cmd = NULL;
int errfd = -1;
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) != offset) {
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))) {
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;
}
cmd = virCommandNewArgList(iohelper_path,
path,
NULL);
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);
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);
}
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);
}
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;
}