qemu/io/channel-command.c
Chetan Pant e0622ae3ca io: Fix Lesser GPL version number
There is no "version 2" of the "Lesser" General Public License.
It is either "GPL version 2.0" or "Lesser GPL version 2.1".
This patch replaces all occurrences of "Lesser GPL version 2" with
"Lesser GPL version 2.1" in comment section.

Signed-off-by: Chetan Pant <chetan4windows@gmail.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-10-29 09:57:37 +00:00

393 lines
11 KiB
C

/*
* QEMU I/O channels external command driver
*
* Copyright (c) 2015 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 "qemu/osdep.h"
#include "io/channel-command.h"
#include "io/channel-watch.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/sockets.h"
#include "trace.h"
QIOChannelCommand *
qio_channel_command_new_pid(int writefd,
int readfd,
pid_t pid)
{
QIOChannelCommand *ioc;
ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND));
ioc->readfd = readfd;
ioc->writefd = writefd;
ioc->pid = pid;
trace_qio_channel_command_new_pid(ioc, writefd, readfd, pid);
return ioc;
}
#ifndef WIN32
QIOChannelCommand *
qio_channel_command_new_spawn(const char *const argv[],
int flags,
Error **errp)
{
pid_t pid = -1;
int stdinfd[2] = { -1, -1 };
int stdoutfd[2] = { -1, -1 };
int devnull = -1;
bool stdinnull = false, stdoutnull = false;
QIOChannelCommand *ioc;
flags = flags & O_ACCMODE;
if (flags == O_RDONLY) {
stdinnull = true;
}
if (flags == O_WRONLY) {
stdoutnull = true;
}
if (stdinnull || stdoutnull) {
devnull = open("/dev/null", O_RDWR);
if (devnull < 0) {
error_setg_errno(errp, errno,
"Unable to open /dev/null");
goto error;
}
}
if ((!stdinnull && pipe(stdinfd) < 0) ||
(!stdoutnull && pipe(stdoutfd) < 0)) {
error_setg_errno(errp, errno,
"Unable to open pipe");
goto error;
}
pid = qemu_fork(errp);
if (pid < 0) {
goto error;
}
if (pid == 0) { /* child */
dup2(stdinnull ? devnull : stdinfd[0], STDIN_FILENO);
dup2(stdoutnull ? devnull : stdoutfd[1], STDOUT_FILENO);
/* Leave stderr connected to qemu's stderr */
if (!stdinnull) {
close(stdinfd[0]);
close(stdinfd[1]);
}
if (!stdoutnull) {
close(stdoutfd[0]);
close(stdoutfd[1]);
}
if (devnull != -1) {
close(devnull);
}
execv(argv[0], (char * const *)argv);
_exit(1);
}
if (!stdinnull) {
close(stdinfd[0]);
}
if (!stdoutnull) {
close(stdoutfd[1]);
}
ioc = qio_channel_command_new_pid(stdinnull ? devnull : stdinfd[1],
stdoutnull ? devnull : stdoutfd[0],
pid);
trace_qio_channel_command_new_spawn(ioc, argv[0], flags);
return ioc;
error:
if (devnull != -1) {
close(devnull);
}
if (stdinfd[0] != -1) {
close(stdinfd[0]);
}
if (stdinfd[1] != -1) {
close(stdinfd[1]);
}
if (stdoutfd[0] != -1) {
close(stdoutfd[0]);
}
if (stdoutfd[1] != -1) {
close(stdoutfd[1]);
}
return NULL;
}
#else /* WIN32 */
QIOChannelCommand *
qio_channel_command_new_spawn(const char *const argv[],
int flags,
Error **errp)
{
error_setg_errno(errp, ENOSYS,
"Command spawn not supported on this platform");
return NULL;
}
#endif /* WIN32 */
#ifndef WIN32
static int qio_channel_command_abort(QIOChannelCommand *ioc,
Error **errp)
{
pid_t ret;
int status;
int step = 0;
/* See if intermediate process has exited; if not, try a nice
* SIGTERM followed by a more severe SIGKILL.
*/
rewait:
trace_qio_channel_command_abort(ioc, ioc->pid);
ret = waitpid(ioc->pid, &status, WNOHANG);
trace_qio_channel_command_wait(ioc, ioc->pid, ret, status);
if (ret == (pid_t)-1) {
if (errno == EINTR) {
goto rewait;
} else {
error_setg_errno(errp, errno,
"Cannot wait on pid %llu",
(unsigned long long)ioc->pid);
return -1;
}
} else if (ret == 0) {
if (step == 0) {
kill(ioc->pid, SIGTERM);
} else if (step == 1) {
kill(ioc->pid, SIGKILL);
} else {
error_setg(errp,
"Process %llu refused to die",
(unsigned long long)ioc->pid);
return -1;
}
step++;
usleep(10 * 1000);
goto rewait;
}
return 0;
}
#endif /* ! WIN32 */
static void qio_channel_command_init(Object *obj)
{
QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
ioc->readfd = -1;
ioc->writefd = -1;
ioc->pid = -1;
}
static void qio_channel_command_finalize(Object *obj)
{
QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
if (ioc->readfd != -1) {
close(ioc->readfd);
}
if (ioc->writefd != -1 &&
ioc->writefd != ioc->readfd) {
close(ioc->writefd);
}
ioc->writefd = ioc->readfd = -1;
if (ioc->pid > 0) {
#ifndef WIN32
qio_channel_command_abort(ioc, NULL);
#endif
}
}
static ssize_t qio_channel_command_readv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds,
size_t *nfds,
Error **errp)
{
QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
ssize_t ret;
retry:
ret = readv(cioc->readfd, iov, niov);
if (ret < 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno,
"Unable to read from command");
return -1;
}
return ret;
}
static ssize_t qio_channel_command_writev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds,
size_t nfds,
Error **errp)
{
QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
ssize_t ret;
retry:
ret = writev(cioc->writefd, iov, niov);
if (ret <= 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno, "%s",
"Unable to write to command");
return -1;
}
return ret;
}
static int qio_channel_command_set_blocking(QIOChannel *ioc,
bool enabled,
Error **errp)
{
QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
if (enabled) {
qemu_set_block(cioc->writefd);
qemu_set_block(cioc->readfd);
} else {
qemu_set_nonblock(cioc->writefd);
qemu_set_nonblock(cioc->readfd);
}
return 0;
}
static int qio_channel_command_close(QIOChannel *ioc,
Error **errp)
{
QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
int rv = 0;
#ifndef WIN32
pid_t wp;
#endif
/* We close FDs before killing, because that
* gives a better chance of clean shutdown
*/
if (cioc->readfd != -1 &&
close(cioc->readfd) < 0) {
rv = -1;
}
if (cioc->writefd != -1 &&
cioc->writefd != cioc->readfd &&
close(cioc->writefd) < 0) {
rv = -1;
}
cioc->writefd = cioc->readfd = -1;
#ifndef WIN32
do {
wp = waitpid(cioc->pid, NULL, 0);
} while (wp == (pid_t)-1 && errno == EINTR);
if (wp == (pid_t)-1) {
error_setg_errno(errp, errno, "Failed to wait for pid %llu",
(unsigned long long)cioc->pid);
return -1;
}
#endif
if (rv < 0) {
error_setg_errno(errp, errno, "%s",
"Unable to close command");
}
return rv;
}
static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc,
AioContext *ctx,
IOHandler *io_read,
IOHandler *io_write,
void *opaque)
{
QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
aio_set_fd_handler(ctx, cioc->readfd, false, io_read, NULL, NULL, opaque);
aio_set_fd_handler(ctx, cioc->writefd, false, NULL, io_write, NULL, opaque);
}
static GSource *qio_channel_command_create_watch(QIOChannel *ioc,
GIOCondition condition)
{
QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
return qio_channel_create_fd_pair_watch(ioc,
cioc->readfd,
cioc->writefd,
condition);
}
static void qio_channel_command_class_init(ObjectClass *klass,
void *class_data G_GNUC_UNUSED)
{
QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
ioc_klass->io_writev = qio_channel_command_writev;
ioc_klass->io_readv = qio_channel_command_readv;
ioc_klass->io_set_blocking = qio_channel_command_set_blocking;
ioc_klass->io_close = qio_channel_command_close;
ioc_klass->io_create_watch = qio_channel_command_create_watch;
ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler;
}
static const TypeInfo qio_channel_command_info = {
.parent = TYPE_QIO_CHANNEL,
.name = TYPE_QIO_CHANNEL_COMMAND,
.instance_size = sizeof(QIOChannelCommand),
.instance_init = qio_channel_command_init,
.instance_finalize = qio_channel_command_finalize,
.class_init = qio_channel_command_class_init,
};
static void qio_channel_command_register_types(void)
{
type_register_static(&qio_channel_command_info);
}
type_init(qio_channel_command_register_types);