[mirror_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 "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 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;
}

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"
	23	#include "io/channel-watch.h"
	24	#include "qemu/sockets.h"
	25	#include "trace.h"
	26
	27
	28	QIOChannelCommand *
	29	qio_channel_command_new_pid(int writefd,
	30	int readfd,
	31	pid_t pid)
	32	{
	33	QIOChannelCommand *ioc;
	34
	35	ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND));
	36
	37	ioc->readfd = readfd;
	38	ioc->writefd = writefd;
	39	ioc->pid = pid;
	40
	41	trace_qio_channel_command_new_pid(ioc, writefd, readfd, pid);
	42	return ioc;
	43	}
	44
	45
	46	#ifndef WIN32
	47	QIOChannelCommand *
	48	qio_channel_command_new_spawn(const char *const argv[],
	49	int flags,
	50	Error **errp)
	51	{
	52	pid_t pid = -1;
	53	int stdinfd[2] = { -1, -1 };
	54	int stdoutfd[2] = { -1, -1 };
	55	int devnull = -1;
	56	bool stdinnull = false, stdoutnull = false;
	57	QIOChannelCommand *ioc;
	58
	59	flags = flags & O_ACCMODE;
	60
	61	if (flags == O_RDONLY) {
	62	stdinnull = true;
	63	}
	64	if (flags == O_WRONLY) {
	65	stdoutnull = true;
	66	}
	67
	68	if (stdinnull \|\| stdoutnull) {
	69	devnull = open("/dev/null", O_RDWR);
e155494c	70	if (devnull < 0) {
195e14d0 DB	71	error_setg_errno(errp, errno,
	72	"Unable to open /dev/null");
	73	goto error;
	74	}
	75	}
	76
	77	if ((!stdinnull && pipe(stdinfd) < 0) \|\|
	78	(!stdoutnull && pipe(stdoutfd) < 0)) {
	79	error_setg_errno(errp, errno,
	80	"Unable to open pipe");
	81	goto error;
	82	}
	83
	84	pid = qemu_fork(errp);
	85	if (pid < 0) {
	86	goto error;
	87	}
	88
	89	if (pid == 0) { /* child */
	90	dup2(stdinnull ? devnull : stdinfd[0], STDIN_FILENO);
	91	dup2(stdoutnull ? devnull : stdoutfd[1], STDOUT_FILENO);
	92	/* Leave stderr connected to qemu's stderr */
	93
	94	if (!stdinnull) {
	95	close(stdinfd[0]);
	96	close(stdinfd[1]);
	97	}
	98	if (!stdoutnull) {
	99	close(stdoutfd[0]);
	100	close(stdoutfd[1]);
	101	}
e155494c DB	102	if (devnull != -1) {
	103	close(devnull);
	104	}
195e14d0 DB	105
	106	execv(argv[0], (char * const *)argv);
	107	_exit(1);
	108	}
	109
	110	if (!stdinnull) {
	111	close(stdinfd[0]);
	112	}
	113	if (!stdoutnull) {
	114	close(stdoutfd[1]);
	115	}
	116
	117	ioc = qio_channel_command_new_pid(stdinnull ? devnull : stdinfd[1],
	118	stdoutnull ? devnull : stdoutfd[0],
	119	pid);
	120	trace_qio_channel_command_new_spawn(ioc, argv[0], flags);
	121	return ioc;
	122
	123	error:
e155494c DB	124	if (devnull != -1) {
	125	close(devnull);
	126	}
195e14d0 DB	127	if (stdinfd[0] != -1) {
	128	close(stdinfd[0]);
	129	}
	130	if (stdinfd[1] != -1) {
	131	close(stdinfd[1]);
	132	}
	133	if (stdoutfd[0] != -1) {
	134	close(stdoutfd[0]);
	135	}
	136	if (stdoutfd[1] != -1) {
	137	close(stdoutfd[1]);
	138	}
	139	return NULL;
	140	}
	141
	142	#else /* WIN32 */
	143	QIOChannelCommand *
	144	qio_channel_command_new_spawn(const char *const argv[],
	145	int flags,
	146	Error **errp)
	147	{
	148	error_setg_errno(errp, ENOSYS,
	149	"Command spawn not supported on this platform");
	150	return NULL;
	151	}
	152	#endif /* WIN32 */
	153
	154	#ifndef WIN32
	155	static int qio_channel_command_abort(QIOChannelCommand *ioc,
	156	Error **errp)
	157	{
	158	pid_t ret;
	159	int status;
	160	int step = 0;
	161
	162	/* See if intermediate process has exited; if not, try a nice
	163	* SIGTERM followed by a more severe SIGKILL.
	164	*/
	165	rewait:
	166	trace_qio_channel_command_abort(ioc, ioc->pid);
	167	ret = waitpid(ioc->pid, &status, WNOHANG);
	168	trace_qio_channel_command_wait(ioc, ioc->pid, ret, status);
	169	if (ret == (pid_t)-1) {
	170	if (errno == EINTR) {
	171	goto rewait;
	172	} else {
	173	error_setg_errno(errp, errno,
	174	"Cannot wait on pid %llu",
	175	(unsigned long long)ioc->pid);
	176	return -1;
	177	}
	178	} else if (ret == 0) {
	179	if (step == 0) {
	180	kill(ioc->pid, SIGTERM);
	181	} else if (step == 1) {
	182	kill(ioc->pid, SIGKILL);
	183	} else {
	184	error_setg(errp,
	185	"Process %llu refused to die",
	186	(unsigned long long)ioc->pid);
	187	return -1;
	188	}
0c0a55b2	189	step++;
195e14d0 DB	190	usleep(10 * 1000);
	191	goto rewait;
	192	}
	193
	194	return 0;
	195	}
	196	#endif /* ! WIN32 */
	197
	198
	199	static void qio_channel_command_init(Object *obj)
	200	{
	201	QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
	202	ioc->readfd = -1;
	203	ioc->writefd = -1;
	204	ioc->pid = -1;
	205	}
	206
	207	static void qio_channel_command_finalize(Object *obj)
	208	{
	209	QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
	210	if (ioc->readfd != -1) {
	211	close(ioc->readfd);
195e14d0	212	}
e155494c DB	213	if (ioc->writefd != -1 &&
e155494c DB	214	ioc->writefd != ioc->readfd) {
195e14d0	215	close(ioc->writefd);
195e14d0	216	}
e155494c	217	ioc->writefd = ioc->readfd = -1;
195e14d0 DB	218	if (ioc->pid > 0) {
	219	#ifndef WIN32
	220	qio_channel_command_abort(ioc, NULL);
	221	#endif
	222	}
	223	}
	224
	225
	226	static ssize_t qio_channel_command_readv(QIOChannel *ioc,
	227	const struct iovec *iov,
	228	size_t niov,
	229	int **fds,
	230	size_t *nfds,
	231	Error **errp)
	232	{
	233	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	234	ssize_t ret;
	235
	236	retry:
	237	ret = readv(cioc->readfd, iov, niov);
	238	if (ret < 0) {
30fd3e27	239	if (errno == EAGAIN) {
195e14d0 DB	240	return QIO_CHANNEL_ERR_BLOCK;
	241	}
	242	if (errno == EINTR) {
	243	goto retry;
	244	}
	245
	246	error_setg_errno(errp, errno,
	247	"Unable to read from command");
	248	return -1;
	249	}
	250
	251	return ret;
	252	}
	253
	254	static ssize_t qio_channel_command_writev(QIOChannel *ioc,
	255	const struct iovec *iov,
	256	size_t niov,
	257	int *fds,
	258	size_t nfds,
	259	Error **errp)
	260	{
	261	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	262	ssize_t ret;
	263
	264	retry:
	265	ret = writev(cioc->writefd, iov, niov);
	266	if (ret <= 0) {
30fd3e27	267	if (errno == EAGAIN) {
195e14d0 DB	268	return QIO_CHANNEL_ERR_BLOCK;
	269	}
	270	if (errno == EINTR) {
	271	goto retry;
	272	}
	273	error_setg_errno(errp, errno, "%s",
	274	"Unable to write to command");
	275	return -1;
	276	}
	277	return ret;
	278	}
	279
	280	static int qio_channel_command_set_blocking(QIOChannel *ioc,
	281	bool enabled,
	282	Error **errp)
	283	{
	284	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	285
	286	if (enabled) {
	287	qemu_set_block(cioc->writefd);
	288	qemu_set_block(cioc->readfd);
	289	} else {
	290	qemu_set_nonblock(cioc->writefd);
	291	qemu_set_nonblock(cioc->readfd);
	292	}
	293
	294	return 0;
	295	}
	296
	297
	298	static int qio_channel_command_close(QIOChannel *ioc,
	299	Error **errp)
	300	{
	301	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	302	int rv = 0;
	303
	304	/* We close FDs before killing, because that
	305	* gives a better chance of clean shutdown
	306	*/
e155494c DB	307	if (cioc->readfd != -1 &&
e155494c DB	308	close(cioc->readfd) < 0) {
195e14d0 DB	309	rv = -1;
195e14d0 DB	310	}
e155494c DB	311	if (cioc->writefd != -1 &&
	312	cioc->writefd != cioc->readfd &&
	313	close(cioc->writefd) < 0) {
195e14d0 DB	314	rv = -1;
195e14d0 DB	315	}
e155494c	316	cioc->writefd = cioc->readfd = -1;
195e14d0 DB	317	#ifndef WIN32
	318	if (qio_channel_command_abort(cioc, errp) < 0) {
	319	return -1;
	320	}
	321	#endif
	322	if (rv < 0) {
	323	error_setg_errno(errp, errno, "%s",
	324	"Unable to close command");
	325	}
	326	return rv;
	327	}
	328
	329
	330	static GSource qio_channel_command_create_watch(QIOChannel ioc,
	331	GIOCondition condition)
	332	{
	333	QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
	334	return qio_channel_create_fd_pair_watch(ioc,
	335	cioc->readfd,
	336	cioc->writefd,
	337	condition);
	338	}
	339
	340
	341	static void qio_channel_command_class_init(ObjectClass *klass,
	342	void *class_data G_GNUC_UNUSED)
	343	{
	344	QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
	345
	346	ioc_klass->io_writev = qio_channel_command_writev;
	347	ioc_klass->io_readv = qio_channel_command_readv;
	348	ioc_klass->io_set_blocking = qio_channel_command_set_blocking;
	349	ioc_klass->io_close = qio_channel_command_close;
	350	ioc_klass->io_create_watch = qio_channel_command_create_watch;
	351	}
	352
	353	static const TypeInfo qio_channel_command_info = {
	354	.parent = TYPE_QIO_CHANNEL,
	355	.name = TYPE_QIO_CHANNEL_COMMAND,
	356	.instance_size = sizeof(QIOChannelCommand),
	357	.instance_init = qio_channel_command_init,
	358	.instance_finalize = qio_channel_command_finalize,
	359	.class_init = qio_channel_command_class_init,
	360	};
	361
	362	static void qio_channel_command_register_types(void)
	363	{
	364	type_register_static(&qio_channel_command_info);
	365	}
	366
	367	type_init(qio_channel_command_register_types);