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-rw-r--r--src/migration/qemu-file-unix.c324
1 files changed, 324 insertions, 0 deletions
diff --git a/src/migration/qemu-file-unix.c b/src/migration/qemu-file-unix.c
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+++ b/src/migration/qemu-file-unix.c
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+/*
+ * 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-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) {
+ err = socket_error();
+
+ if (err != EAGAIN && err != EWOULDBLOCK) {
+ error_report("socket_writev_buffer: Got err=%d for (%zu/%zu)",
+ err, (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 -err;
+ }
+
+ /* 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 (socket_error() == EAGAIN) {
+ yield_until_fd_readable(s->fd);
+ } else if (socket_error() != EINTR) {
+ break;
+ }
+ }
+
+ if (len == -1) {
+ len = -socket_error();
+ }
+ 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;
+}
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