[qemu.git] / io / channel-command.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 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/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;

    /* 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
    if (qio_channel_command_abort(cioc, errp) < 0) {
        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);
Commit	Line	Data
195e14d0 DB	1	/*
	2	* QEMU I/O channels external command driver
	3	*
	4	* Copyright (c) 2015 Red Hat, Inc.
	5	*
	6	* This library is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2 of the License, or (at your option) any later version.
	10	*
	11	* This library is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with this library; if not, see <http://www.gnu.org/licenses/>.
	18	*
	19	*/
	20
cae9fc56	21	#include "qemu/osdep.h"
195e14d0 DB	22	#include "io/channel-command.h"
195e14d0 DB	23	#include "io/channel-watch.h"
da34e65c	24	#include "qapi/error.h"
195e14d0 DB	25	#include "qemu/sockets.h"
	26	#include "trace.h"
	27
	28
	29	QIOChannelCommand *
	30	qio_channel_command_new_pid(int writefd,
	31	int readfd,
	32	pid_t pid)
	33	{
	34	QIOChannelCommand *ioc;
	35
	36	ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND));
	37
	38	ioc->readfd = readfd;
	39	ioc->writefd = writefd;
	40	ioc->pid = pid;
	41
	42	trace_qio_channel_command_new_pid(ioc, writefd, readfd, pid);
	43	return ioc;
	44	}
	45
	46
	47	#ifndef WIN32
	48	QIOChannelCommand *
	49	qio_channel_command_new_spawn(const char *const argv[],
	50	int flags,
	51	Error **errp)
	52	{
	53	pid_t pid = -1;
	54	int stdinfd[2] = { -1, -1 };
	55	int stdoutfd[2] = { -1, -1 };
	56	int devnull = -1;
	57	bool stdinnull = false, stdoutnull = false;
	58	QIOChannelCommand *ioc;
	59
	60	flags = flags & O_ACCMODE;
	61
	62	if (flags == O_RDONLY) {
	63	stdinnull = true;
	64	}
	65	if (flags == O_WRONLY) {
	66	stdoutnull = true;
	67	}
	68
	69	if (stdinnull \|\| stdoutnull) {
	70	devnull = open("/dev/null", O_RDWR);
e155494c	71	if (devnull < 0) {
195e14d0 DB	72	error_setg_errno(errp, errno,
	73	"Unable to open /dev/null");
	74	goto error;
	75	}
	76	}
	77
	78	if ((!stdinnull && pipe(stdinfd) < 0) \|\|
	79	(!stdoutnull && pipe(stdoutfd) < 0)) {
	80	error_setg_errno(errp, errno,
	81	"Unable to open pipe");
	82	goto error;
	83	}
	84
	85	pid = qemu_fork(errp);
	86	if (pid < 0) {
	87	goto error;
	88	}
	89
	90	if (pid == 0) { /* child */
	91	dup2(stdinnull ? devnull : stdinfd[0], STDIN_FILENO);
	92	dup2(stdoutnull ? devnull : stdoutfd[1], STDOUT_FILENO);
	93	/* Leave stderr connected to qemu's stderr */
	94
	95	if (!stdinnull) {
	96	close(stdinfd[0]);
	97	close(stdinfd[1]);
	98	}
	99	if (!stdoutnull) {
	100	close(stdoutfd[0]);
	101	close(stdoutfd[1]);
	102	}
e155494c DB	103	if (devnull != -1) {
	104	close(devnull);
	105	}
195e14d0 DB	106
	107	execv(argv[0], (char * const *)argv);
	108	_exit(1);
	109	}
	110
	111	if (!stdinnull) {
	112	close(stdinfd[0]);
	113	}
	114	if (!stdoutnull) {
	115	close(stdoutfd[1]);
	116	}
	117
	118	ioc = qio_channel_command_new_pid(stdinnull ? devnull : stdinfd[1],
	119	stdoutnull ? devnull : stdoutfd[0],
	120	pid);
	121	trace_qio_channel_command_new_spawn(ioc, argv[0], flags);
	122	return ioc;
	123
	124	error:
e155494c DB	125	if (devnull != -1) {
	126	close(devnull);
	127	}
195e14d0 DB	128	if (stdinfd[0] != -1) {
	129	close(stdinfd[0]);
	130	}
	131	if (stdinfd[1] != -1) {
	132	close(stdinfd[1]);
	133	}
	134	if (stdoutfd[0] != -1) {
	135	close(stdoutfd[0]);
	136	}
	137	if (stdoutfd[1] != -1) {
	138	close(stdoutfd[1]);
	139	}
	140	return NULL;
	141	}
	142
	143	#else /* WIN32 */
	144	QIOChannelCommand *
	145	qio_channel_command_new_spawn(const char *const argv[],
	146	int flags,
	147	Error **errp)
	148	{
	149	error_setg_errno(errp, ENOSYS,
	150	"Command spawn not supported on this platform");
	151	return NULL;
	152	}
	153	#endif /* WIN32 */
	154
	155	#ifndef WIN32
	156	static int qio_channel_command_abort(QIOChannelCommand *ioc,
	157	Error **errp)
	158	{
	159	pid_t ret;
	160	int status;
	161	int step = 0;
	162
	163	/* See if intermediate process has exited; if not, try a nice
	164	* SIGTERM followed by a more severe SIGKILL.
	165	*/
	166	rewait:
	167	trace_qio_channel_command_abort(ioc, ioc->pid);
	168	ret = waitpid(ioc->pid, &status, WNOHANG);
	169	trace_qio_channel_command_wait(ioc, ioc->pid, ret, status);
	170	if (ret == (pid_t)-1) {
	171	if (errno == EINTR) {
	172	goto rewait;
	173	} else {
	174	error_setg_errno(errp, errno,
	175	"Cannot wait on pid %llu",
	176	(unsigned long long)ioc->pid);
	177	return -1;
	178	}
	179	} else if (ret == 0) {
	180	if (step == 0) {
	181	kill(ioc->pid, SIGTERM);
	182	} else if (step == 1) {
	183	kill(ioc->pid, SIGKILL);
	184	} else {
	185	error_setg(errp,
	186	"Process %llu refused to die",
	187	(unsigned long long)ioc->pid);
	188	return -1;
	189	}
0c0a55b2	190	step++;
195e14d0 DB	191	usleep(10 * 1000);
	192	goto rewait;
	193	}
	194
	195	return 0;
	196	}
	197	#endif /* ! WIN32 */
	198
	199
	200	static void qio_channel_command_init(Object *obj)
	201	{
	202	QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
	203	ioc->readfd = -1;
	204	ioc->writefd = -1;
	205	ioc->pid = -1;
	206	}
	207
	208	static void qio_channel_command_finalize(Object *obj)
	209	{
	210	QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
	211	if (ioc->readfd != -1) {
	212	close(ioc->readfd);
195e14d0	213	}
e155494c DB	214	if (ioc->writefd != -1 &&
e155494c DB	215	ioc->writefd != ioc->readfd) {
195e14d0	216	close(ioc->writefd);
195e14d0	217	}
e155494c	218	ioc->writefd = ioc->readfd = -1;
195e14d0 DB	219	if (ioc->pid > 0) {
	220	#ifndef WIN32
	221	qio_channel_command_abort(ioc, NULL);
	222	#endif
	223	}
	224	}
	225
	226
	227	static ssize_t qio_channel_command_readv(QIOChannel *ioc,
	228	const struct iovec *iov,
	229	size_t niov,
	230	int **fds,
	231	size_t *nfds,
	232	Error **errp)
	233	{
	234	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	235	ssize_t ret;
	236
	237	retry:
	238	ret = readv(cioc->readfd, iov, niov);
	239	if (ret < 0) {
30fd3e27	240	if (errno == EAGAIN) {
195e14d0 DB	241	return QIO_CHANNEL_ERR_BLOCK;
	242	}
	243	if (errno == EINTR) {
	244	goto retry;
	245	}
	246
	247	error_setg_errno(errp, errno,
	248	"Unable to read from command");
	249	return -1;
	250	}
	251
	252	return ret;
	253	}
	254
	255	static ssize_t qio_channel_command_writev(QIOChannel *ioc,
	256	const struct iovec *iov,
	257	size_t niov,
	258	int *fds,
	259	size_t nfds,
	260	Error **errp)
	261	{
	262	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	263	ssize_t ret;
	264
	265	retry:
	266	ret = writev(cioc->writefd, iov, niov);
	267	if (ret <= 0) {
30fd3e27	268	if (errno == EAGAIN) {
195e14d0 DB	269	return QIO_CHANNEL_ERR_BLOCK;
	270	}
	271	if (errno == EINTR) {
	272	goto retry;
	273	}
	274	error_setg_errno(errp, errno, "%s",
	275	"Unable to write to command");
	276	return -1;
	277	}
	278	return ret;
	279	}
	280
	281	static int qio_channel_command_set_blocking(QIOChannel *ioc,
	282	bool enabled,
	283	Error **errp)
	284	{
	285	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	286
	287	if (enabled) {
	288	qemu_set_block(cioc->writefd);
	289	qemu_set_block(cioc->readfd);
	290	} else {
	291	qemu_set_nonblock(cioc->writefd);
	292	qemu_set_nonblock(cioc->readfd);
	293	}
	294
	295	return 0;
	296	}
	297
	298
	299	static int qio_channel_command_close(QIOChannel *ioc,
	300	Error **errp)
	301	{
	302	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	303	int rv = 0;
	304
	305	/* We close FDs before killing, because that
	306	* gives a better chance of clean shutdown
	307	*/
e155494c DB	308	if (cioc->readfd != -1 &&
e155494c DB	309	close(cioc->readfd) < 0) {
195e14d0 DB	310	rv = -1;
195e14d0 DB	311	}
e155494c DB	312	if (cioc->writefd != -1 &&
	313	cioc->writefd != cioc->readfd &&
	314	close(cioc->writefd) < 0) {
195e14d0 DB	315	rv = -1;
195e14d0 DB	316	}
e155494c	317	cioc->writefd = cioc->readfd = -1;
195e14d0 DB	318	#ifndef WIN32
	319	if (qio_channel_command_abort(cioc, errp) < 0) {
	320	return -1;
	321	}
	322	#endif
	323	if (rv < 0) {
	324	error_setg_errno(errp, errno, "%s",
	325	"Unable to close command");
	326	}
	327	return rv;
	328	}
	329
	330
bf88c124 PB	331	static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc,
	332	AioContext *ctx,
	333	IOHandler *io_read,
	334	IOHandler *io_write,
	335	void *opaque)
	336	{
	337	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	338	aio_set_fd_handler(ctx, cioc->readfd, false, io_read, NULL, NULL, opaque);
	339	aio_set_fd_handler(ctx, cioc->writefd, false, NULL, io_write, NULL, opaque);
	340	}
	341
	342
195e14d0 DB	343	static GSource qio_channel_command_create_watch(QIOChannel ioc,
	344	GIOCondition condition)
	345	{
	346	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	347	return qio_channel_create_fd_pair_watch(ioc,
	348	cioc->readfd,
	349	cioc->writefd,
	350	condition);
	351	}
	352
	353
	354	static void qio_channel_command_class_init(ObjectClass *klass,
	355	void *class_data G_GNUC_UNUSED)
	356	{
	357	QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
	358
	359	ioc_klass->io_writev = qio_channel_command_writev;
	360	ioc_klass->io_readv = qio_channel_command_readv;
	361	ioc_klass->io_set_blocking = qio_channel_command_set_blocking;
	362	ioc_klass->io_close = qio_channel_command_close;
	363	ioc_klass->io_create_watch = qio_channel_command_create_watch;
bf88c124	364	ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler;
195e14d0 DB	365	}
	366
	367	static const TypeInfo qio_channel_command_info = {
	368	.parent = TYPE_QIO_CHANNEL,
	369	.name = TYPE_QIO_CHANNEL_COMMAND,
	370	.instance_size = sizeof(QIOChannelCommand),
	371	.instance_init = qio_channel_command_init,
	372	.instance_finalize = qio_channel_command_finalize,
	373	.class_init = qio_channel_command_class_init,
	374	};
	375
	376	static void qio_channel_command_register_types(void)
	377	{
	378	type_register_static(&qio_channel_command_info);
	379	}
	380
	381	type_init(qio_channel_command_register_types);