[qemu.git] / migration / qemu-file-unix.c

/*
 * QEMU System Emulator
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "qemu/iov.h"
#include "qemu/sockets.h"
#include "qemu/coroutine.h"
#include "migration/qemu-file.h"
#include "migration/qemu-file-internal.h"

typedef struct QEMUFileSocket {
    int fd;
    QEMUFile *file;
} QEMUFileSocket;

static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
                                    int64_t pos)
{
    QEMUFileSocket *s = opaque;
    ssize_t len;
    ssize_t size = iov_size(iov, iovcnt);
    ssize_t offset = 0;
    int     err;

    while (size > 0) {
        len = iov_send(s->fd, iov, iovcnt, offset, size);

        if (len > 0) {
            size -= len;
            offset += len;
        }

        if (size > 0) {
            if (errno != EAGAIN && errno != EWOULDBLOCK) {
                error_report("socket_writev_buffer: Got err=%d for (%zu/%zu)",
                             errno, (size_t)size, (size_t)len);
                /*
                 * If I've already sent some but only just got the error, I
                 * could return the amount validly sent so far and wait for the
                 * next call to report the error, but I'd rather flag the error
                 * immediately.
                 */
                return -errno;
            }

            /* Emulate blocking */
            GPollFD pfd;

            pfd.fd = s->fd;
            pfd.events = G_IO_OUT | G_IO_ERR;
            pfd.revents = 0;
            TFR(err = g_poll(&pfd, 1, -1 /* no timeout */));
            /* Errors other than EINTR intentionally ignored */
        }
     }

    return offset;
}

static int socket_get_fd(void *opaque)
{
    QEMUFileSocket *s = opaque;

    return s->fd;
}

static ssize_t socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
                                 size_t size)
{
    QEMUFileSocket *s = opaque;
    ssize_t len;

    for (;;) {
        len = qemu_recv(s->fd, buf, size, 0);
        if (len != -1) {
            break;
        }
        if (errno == EAGAIN) {
            yield_until_fd_readable(s->fd);
        } else if (errno != EINTR) {
            break;
        }
    }

    if (len == -1) {
        len = -errno;
    }
    return len;
}

static int socket_close(void *opaque)
{
    QEMUFileSocket *s = opaque;
    closesocket(s->fd);
    g_free(s);
    return 0;
}

static int socket_shutdown(void *opaque, bool rd, bool wr)
{
    QEMUFileSocket *s = opaque;

    if (shutdown(s->fd, rd ? (wr ? SHUT_RDWR : SHUT_RD) : SHUT_WR)) {
        return -errno;
    } else {
        return 0;
    }
}

static int socket_return_close(void *opaque)
{
    QEMUFileSocket *s = opaque;
    /*
     * Note: We don't close the socket, that should be done by the forward
     * path.
     */
    g_free(s);
    return 0;
}

static const QEMUFileOps socket_return_read_ops = {
    .get_fd          = socket_get_fd,
    .get_buffer      = socket_get_buffer,
    .close           = socket_return_close,
    .shut_down       = socket_shutdown,
};

static const QEMUFileOps socket_return_write_ops = {
    .get_fd          = socket_get_fd,
    .writev_buffer   = socket_writev_buffer,
    .close           = socket_return_close,
    .shut_down       = socket_shutdown,
};

/*
 * Give a QEMUFile* off the same socket but data in the opposite
 * direction.
 */
static QEMUFile *socket_get_return_path(void *opaque)
{
    QEMUFileSocket *forward = opaque;
    QEMUFileSocket *reverse;

    if (qemu_file_get_error(forward->file)) {
        /* If the forward file is in error, don't try and open a return */
        return NULL;
    }

    reverse = g_malloc0(sizeof(QEMUFileSocket));
    reverse->fd = forward->fd;
    /* I don't think there's a better way to tell which direction 'this' is */
    if (forward->file->ops->get_buffer != NULL) {
        /* being called from the read side, so we need to be able to write */
        return qemu_fopen_ops(reverse, &socket_return_write_ops);
    } else {
        return qemu_fopen_ops(reverse, &socket_return_read_ops);
    }
}

static ssize_t unix_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
                                  int64_t pos)
{
    QEMUFileSocket *s = opaque;
    ssize_t len, offset;
    ssize_t size = iov_size(iov, iovcnt);
    ssize_t total = 0;

    assert(iovcnt > 0);
    offset = 0;
    while (size > 0) {
        /* Find the next start position; skip all full-sized vector elements  */
        while (offset >= iov[0].iov_len) {
            offset -= iov[0].iov_len;
            iov++, iovcnt--;
        }

        /* skip `offset' bytes from the (now) first element, undo it on exit */
        assert(iovcnt > 0);
        iov[0].iov_base += offset;
        iov[0].iov_len -= offset;

        do {
            len = writev(s->fd, iov, iovcnt);
        } while (len == -1 && errno == EINTR);
        if (len == -1) {
            return -errno;
        }

        /* Undo the changes above */
        iov[0].iov_base -= offset;
        iov[0].iov_len += offset;

        /* Prepare for the next iteration */
        offset += len;
        total += len;
        size -= len;
    }

    return total;
}

static ssize_t unix_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
                              size_t size)
{
    QEMUFileSocket *s = opaque;
    ssize_t len;

    for (;;) {
        len = read(s->fd, buf, size);
        if (len != -1) {
            break;
        }
        if (errno == EAGAIN) {
            yield_until_fd_readable(s->fd);
        } else if (errno != EINTR) {
            break;
        }
    }

    if (len == -1) {
        len = -errno;
    }
    return len;
}

static int unix_close(void *opaque)
{
    QEMUFileSocket *s = opaque;
    close(s->fd);
    g_free(s);
    return 0;
}

static const QEMUFileOps unix_read_ops = {
    .get_fd =     socket_get_fd,
    .get_buffer = unix_get_buffer,
    .close =      unix_close
};

static const QEMUFileOps unix_write_ops = {
    .get_fd =     socket_get_fd,
    .writev_buffer = unix_writev_buffer,
    .close =      unix_close
};

QEMUFile *qemu_fdopen(int fd, const char *mode)
{
    QEMUFileSocket *s;

    if (mode == NULL ||
        (mode[0] != 'r' && mode[0] != 'w') ||
        mode[1] != 'b' || mode[2] != 0) {
        fprintf(stderr, "qemu_fdopen: Argument validity check failed\n");
        return NULL;
    }

    s = g_new0(QEMUFileSocket, 1);
    s->fd = fd;

    if (mode[0] == 'r') {
        s->file = qemu_fopen_ops(s, &unix_read_ops);
    } else {
        s->file = qemu_fopen_ops(s, &unix_write_ops);
    }
    return s->file;
}

static const QEMUFileOps socket_read_ops = {
    .get_fd          = socket_get_fd,
    .get_buffer      = socket_get_buffer,
    .close           = socket_close,
    .shut_down       = socket_shutdown,
    .get_return_path = socket_get_return_path
};

static const QEMUFileOps socket_write_ops = {
    .get_fd          = socket_get_fd,
    .writev_buffer   = socket_writev_buffer,
    .close           = socket_close,
    .shut_down       = socket_shutdown,
    .get_return_path = socket_get_return_path
};

QEMUFile *qemu_fopen_socket(int fd, const char *mode)
{
    QEMUFileSocket *s;

    if (qemu_file_mode_is_not_valid(mode)) {
        return NULL;
    }

    s = g_new0(QEMUFileSocket, 1);
    s->fd = fd;
    if (mode[0] == 'w') {
        qemu_set_block(s->fd);
        s->file = qemu_fopen_ops(s, &socket_write_ops);
    } else {
        s->file = qemu_fopen_ops(s, &socket_read_ops);
    }
    return s->file;
}
Commit	Line	Data
bee223ba EH	1	/*
	2	* QEMU System Emulator
	3	*
	4	* Copyright (c) 2003-2008 Fabrice Bellard
	5	*
	6	* Permission is hereby granted, free of charge, to any person obtaining a copy
	7	* of this software and associated documentation files (the "Software"), to deal
	8	* in the Software without restriction, including without limitation the rights
	9	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	10	* copies of the Software, and to permit persons to whom the Software is
	11	* furnished to do so, subject to the following conditions:
	12	*
	13	* The above copyright notice and this permission notice shall be included in
	14	* all copies or substantial portions of the Software.
	15	*
	16	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	17	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	18	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	19	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	20	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	21	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	22	* THE SOFTWARE.
	23	*/
1393a485	24	#include "qemu/osdep.h"
bee223ba	25	#include "qemu-common.h"
3e4097b5	26	#include "qemu/error-report.h"
bee223ba EH	27	#include "qemu/iov.h"
bee223ba EH	28	#include "qemu/sockets.h"
10817bf0	29	#include "qemu/coroutine.h"
bee223ba	30	#include "migration/qemu-file.h"
e1a8c9b6	31	#include "migration/qemu-file-internal.h"
bee223ba EH	32
	33	typedef struct QEMUFileSocket {
	34	int fd;
	35	QEMUFile *file;
	36	} QEMUFileSocket;
	37
	38	static ssize_t socket_writev_buffer(void opaque, struct iovec iov, int iovcnt,
	39	int64_t pos)
	40	{
	41	QEMUFileSocket *s = opaque;
	42	ssize_t len;
	43	ssize_t size = iov_size(iov, iovcnt);
3e4097b5 DDAG	44	ssize_t offset = 0;
3e4097b5 DDAG	45	int err;
bee223ba	46
3e4097b5 DDAG	47	while (size > 0) {
	48	len = iov_send(s->fd, iov, iovcnt, offset, size);
	49
	50	if (len > 0) {
	51	size -= len;
	52	offset += len;
	53	}
	54
	55	if (size > 0) {
b16a44e1	56	if (errno != EAGAIN && errno != EWOULDBLOCK) {
3e4097b5	57	error_report("socket_writev_buffer: Got err=%d for (%zu/%zu)",
b16a44e1	58	errno, (size_t)size, (size_t)len);
3e4097b5 DDAG	59	/*
	60	* If I've already sent some but only just got the error, I
	61	* could return the amount validly sent so far and wait for the
	62	* next call to report the error, but I'd rather flag the error
	63	* immediately.
	64	*/
b16a44e1	65	return -errno;
3e4097b5 DDAG	66	}
	67
	68	/* Emulate blocking */
	69	GPollFD pfd;
	70
	71	pfd.fd = s->fd;
	72	pfd.events = G_IO_OUT \| G_IO_ERR;
	73	pfd.revents = 0;
4e39f57c MA	74	TFR(err = g_poll(&pfd, 1, -1 /* no timeout */));
4e39f57c MA	75	/* Errors other than EINTR intentionally ignored */
3e4097b5 DDAG	76	}
	77	}
	78
	79	return offset;
bee223ba EH	80	}
	81
	82	static int socket_get_fd(void *opaque)
	83	{
	84	QEMUFileSocket *s = opaque;
	85
	86	return s->fd;
	87	}
	88
a202a4c0 DDAG	89	static ssize_t socket_get_buffer(void opaque, uint8_t buf, int64_t pos,
a202a4c0 DDAG	90	size_t size)
bee223ba EH	91	{
	92	QEMUFileSocket *s = opaque;
	93	ssize_t len;
	94
	95	for (;;) {
	96	len = qemu_recv(s->fd, buf, size, 0);
	97	if (len != -1) {
	98	break;
	99	}
b16a44e1	100	if (errno == EAGAIN) {
bee223ba	101	yield_until_fd_readable(s->fd);
b16a44e1	102	} else if (errno != EINTR) {
bee223ba EH	103	break;
	104	}
	105	}
	106
	107	if (len == -1) {
b16a44e1	108	len = -errno;
bee223ba EH	109	}
	110	return len;
	111	}
	112
	113	static int socket_close(void *opaque)
	114	{
	115	QEMUFileSocket *s = opaque;
	116	closesocket(s->fd);
	117	g_free(s);
	118	return 0;
	119	}
	120
e1a8c9b6 DDAG	121	static int socket_shutdown(void *opaque, bool rd, bool wr)
	122	{
	123	QEMUFileSocket *s = opaque;
	124
	125	if (shutdown(s->fd, rd ? (wr ? SHUT_RDWR : SHUT_RD) : SHUT_WR)) {
	126	return -errno;
	127	} else {
	128	return 0;
	129	}
	130	}
	131
adc468e9 DDAG	132	static int socket_return_close(void *opaque)
	133	{
	134	QEMUFileSocket *s = opaque;
	135	/*
	136	* Note: We don't close the socket, that should be done by the forward
	137	* path.
	138	*/
	139	g_free(s);
	140	return 0;
	141	}
	142
	143	static const QEMUFileOps socket_return_read_ops = {
	144	.get_fd = socket_get_fd,
	145	.get_buffer = socket_get_buffer,
	146	.close = socket_return_close,
	147	.shut_down = socket_shutdown,
	148	};
	149
	150	static const QEMUFileOps socket_return_write_ops = {
	151	.get_fd = socket_get_fd,
	152	.writev_buffer = socket_writev_buffer,
	153	.close = socket_return_close,
	154	.shut_down = socket_shutdown,
	155	};
	156
	157	/*
	158	* Give a QEMUFile* off the same socket but data in the opposite
	159	* direction.
	160	*/
	161	static QEMUFile socket_get_return_path(void opaque)
	162	{
	163	QEMUFileSocket *forward = opaque;
	164	QEMUFileSocket *reverse;
	165
	166	if (qemu_file_get_error(forward->file)) {
	167	/* If the forward file is in error, don't try and open a return */
	168	return NULL;
	169	}
	170
	171	reverse = g_malloc0(sizeof(QEMUFileSocket));
	172	reverse->fd = forward->fd;
	173	/* I don't think there's a better way to tell which direction 'this' is */
	174	if (forward->file->ops->get_buffer != NULL) {
	175	/* being called from the read side, so we need to be able to write */
	176	return qemu_fopen_ops(reverse, &socket_return_write_ops);
	177	} else {
	178	return qemu_fopen_ops(reverse, &socket_return_read_ops);
	179	}
	180	}
	181
bee223ba EH	182	static ssize_t unix_writev_buffer(void opaque, struct iovec iov, int iovcnt,
	183	int64_t pos)
	184	{
	185	QEMUFileSocket *s = opaque;
	186	ssize_t len, offset;
	187	ssize_t size = iov_size(iov, iovcnt);
	188	ssize_t total = 0;
	189
	190	assert(iovcnt > 0);
	191	offset = 0;
	192	while (size > 0) {
	193	/* Find the next start position; skip all full-sized vector elements */
	194	while (offset >= iov[0].iov_len) {
	195	offset -= iov[0].iov_len;
	196	iov++, iovcnt--;
	197	}
	198
	199	/* skip `offset' bytes from the (now) first element, undo it on exit */
	200	assert(iovcnt > 0);
	201	iov[0].iov_base += offset;
	202	iov[0].iov_len -= offset;
	203
	204	do {
	205	len = writev(s->fd, iov, iovcnt);
	206	} while (len == -1 && errno == EINTR);
	207	if (len == -1) {
	208	return -errno;
	209	}
	210
	211	/* Undo the changes above */
	212	iov[0].iov_base -= offset;
	213	iov[0].iov_len += offset;
	214
	215	/* Prepare for the next iteration */
	216	offset += len;
	217	total += len;
	218	size -= len;
	219	}
	220
	221	return total;
	222	}
	223
a202a4c0 DDAG	224	static ssize_t unix_get_buffer(void opaque, uint8_t buf, int64_t pos,
a202a4c0 DDAG	225	size_t size)
bee223ba EH	226	{
	227	QEMUFileSocket *s = opaque;
	228	ssize_t len;
	229
	230	for (;;) {
	231	len = read(s->fd, buf, size);
	232	if (len != -1) {
	233	break;
	234	}
	235	if (errno == EAGAIN) {
	236	yield_until_fd_readable(s->fd);
	237	} else if (errno != EINTR) {
	238	break;
	239	}
	240	}
	241
	242	if (len == -1) {
	243	len = -errno;
	244	}
	245	return len;
	246	}
	247
	248	static int unix_close(void *opaque)
	249	{
	250	QEMUFileSocket *s = opaque;
	251	close(s->fd);
	252	g_free(s);
	253	return 0;
	254	}
	255
	256	static const QEMUFileOps unix_read_ops = {
	257	.get_fd = socket_get_fd,
	258	.get_buffer = unix_get_buffer,
	259	.close = unix_close
	260	};
	261
	262	static const QEMUFileOps unix_write_ops = {
	263	.get_fd = socket_get_fd,
	264	.writev_buffer = unix_writev_buffer,
	265	.close = unix_close
	266	};
	267
	268	QEMUFile qemu_fdopen(int fd, const char mode)
	269	{
	270	QEMUFileSocket *s;
	271
	272	if (mode == NULL \|\|
	273	(mode[0] != 'r' && mode[0] != 'w') \|\|
	274	mode[1] != 'b' \|\| mode[2] != 0) {
	275	fprintf(stderr, "qemu_fdopen: Argument validity check failed\n");
	276	return NULL;
	277	}
	278
97f3ad35	279	s = g_new0(QEMUFileSocket, 1);
bee223ba EH	280	s->fd = fd;
	281
	282	if (mode[0] == 'r') {
	283	s->file = qemu_fopen_ops(s, &unix_read_ops);
	284	} else {
	285	s->file = qemu_fopen_ops(s, &unix_write_ops);
	286	}
	287	return s->file;
	288	}
	289
	290	static const QEMUFileOps socket_read_ops = {
adc468e9 DDAG	291	.get_fd = socket_get_fd,
	292	.get_buffer = socket_get_buffer,
	293	.close = socket_close,
	294	.shut_down = socket_shutdown,
	295	.get_return_path = socket_get_return_path
bee223ba EH	296	};
	297
	298	static const QEMUFileOps socket_write_ops = {
adc468e9 DDAG	299	.get_fd = socket_get_fd,
	300	.writev_buffer = socket_writev_buffer,
	301	.close = socket_close,
	302	.shut_down = socket_shutdown,
	303	.get_return_path = socket_get_return_path
bee223ba EH	304	};
	305
	306	QEMUFile qemu_fopen_socket(int fd, const char mode)
	307	{
	308	QEMUFileSocket *s;
	309
	310	if (qemu_file_mode_is_not_valid(mode)) {
	311	return NULL;
	312	}
	313
97f3ad35	314	s = g_new0(QEMUFileSocket, 1);
bee223ba EH	315	s->fd = fd;
	316	if (mode[0] == 'w') {
	317	qemu_set_block(s->fd);
	318	s->file = qemu_fopen_ops(s, &socket_write_ops);
	319	} else {
	320	s->file = qemu_fopen_ops(s, &socket_read_ops);
	321	}
	322	return s->file;
	323	}