qemu-file: Move QEMUFile code to qemu-file.c (093c455a) · Commits · SUMMER2020 / students / proj-2021291

Makefile.objs

+1 −0

Original line number	Diff line number	Diff line
		@@ -52,6 +52,7 @@ common-obj-$(CONFIG_LINUX) += fsdev/

		common-obj-y += migration.o migration-tcp.o
		common-obj-y += vmstate.o
		common-obj-y += qemu-file.o
		common-obj-$(CONFIG_RDMA) += migration-rdma.o
		common-obj-y += qemu-char.o #aio.o
		common-obj-y += block-migration.o

qemu-file.c

0 → 100644

+826 −0

Original line number	Diff line number	Diff line
		#include "qemu-common.h"
		#include "qemu/iov.h"
		#include "qemu/sockets.h"
		#include "block/coroutine.h"
		#include "migration/migration.h"
		#include "migration/qemu-file.h"

		#define IO_BUF_SIZE 32768
		#define MAX_IOV_SIZE MIN(IOV_MAX, 64)

		struct QEMUFile {
		const QEMUFileOps *ops;
		void *opaque;

		int64_t bytes_xfer;
		int64_t xfer_limit;

		int64_t pos; /* start of buffer when writing, end of buffer
		when reading */
		int buf_index;
		int buf_size; /* 0 when writing */
		uint8_t buf[IO_BUF_SIZE];

		struct iovec iov[MAX_IOV_SIZE];
		unsigned int iovcnt;

		int last_error;
		};

		typedef struct QEMUFileStdio {
		FILE *stdio_file;
		QEMUFile *file;
		} QEMUFileStdio;

		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);

		len = iov_send(s->fd, iov, iovcnt, 0, size);
		if (len < size) {
		len = -socket_error();
		}
		return len;
		}

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

		return s->fd;
		}

		static int socket_get_buffer(void opaque, uint8_t buf, int64_t pos, int 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 stdio_get_fd(void *opaque)
		{
		QEMUFileStdio *s = opaque;

		return fileno(s->stdio_file);
		}

		static int stdio_put_buffer(void opaque, const uint8_t buf, int64_t pos,
		int size)
		{
		QEMUFileStdio *s = opaque;
		return fwrite(buf, 1, size, s->stdio_file);
		}

		static int stdio_get_buffer(void opaque, uint8_t buf, int64_t pos, int size)
		{
		QEMUFileStdio *s = opaque;
		FILE *fp = s->stdio_file;
		int bytes;

		for (;;) {
		clearerr(fp);
		bytes = fread(buf, 1, size, fp);
		if (bytes != 0 \|\| !ferror(fp)) {
		break;
		}
		if (errno == EAGAIN) {
		yield_until_fd_readable(fileno(fp));
		} else if (errno != EINTR) {
		break;
		}
		}
		return bytes;
		}

		static int stdio_pclose(void *opaque)
		{
		QEMUFileStdio *s = opaque;
		int ret;
		ret = pclose(s->stdio_file);
		if (ret == -1) {
		ret = -errno;
		} else if (!WIFEXITED(ret) \|\| WEXITSTATUS(ret) != 0) {
		/* close succeeded, but non-zero exit code: */
		ret = -EIO; /* fake errno value */
		}
		g_free(s);
		return ret;
		}

		static int stdio_fclose(void *opaque)
		{
		QEMUFileStdio *s = opaque;
		int ret = 0;

		if (s->file->ops->put_buffer \|\| s->file->ops->writev_buffer) {
		int fd = fileno(s->stdio_file);
		struct stat st;

		ret = fstat(fd, &st);
		if (ret == 0 && S_ISREG(st.st_mode)) {
		/*
		* If the file handle is a regular file make sure the
		* data is flushed to disk before signaling success.
		*/
		ret = fsync(fd);
		if (ret != 0) {
		ret = -errno;
		return ret;
		}
		}
		}
		if (fclose(s->stdio_file) == EOF) {
		ret = -errno;
		}
		g_free(s);
		return ret;
		}

		static const QEMUFileOps stdio_pipe_read_ops = {
		.get_fd = stdio_get_fd,
		.get_buffer = stdio_get_buffer,
		.close = stdio_pclose
		};

		static const QEMUFileOps stdio_pipe_write_ops = {
		.get_fd = stdio_get_fd,
		.put_buffer = stdio_put_buffer,
		.close = stdio_pclose
		};

		QEMUFile qemu_popen_cmd(const char command, const char *mode)
		{
		FILE *stdio_file;
		QEMUFileStdio *s;

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

		stdio_file = popen(command, mode);
		if (stdio_file == NULL) {
		return NULL;
		}

		s = g_malloc0(sizeof(QEMUFileStdio));

		s->stdio_file = stdio_file;

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

		static const QEMUFileOps stdio_file_read_ops = {
		.get_fd = stdio_get_fd,
		.get_buffer = stdio_get_buffer,
		.close = stdio_fclose
		};

		static const QEMUFileOps stdio_file_write_ops = {
		.get_fd = stdio_get_fd,
		.put_buffer = stdio_put_buffer,
		.close = stdio_fclose
		};

		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 int unix_get_buffer(void opaque, uint8_t buf, int64_t pos, int 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_malloc0(sizeof(QEMUFileSocket));
		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
		};

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

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

		return false;
		}

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

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

		s = g_malloc0(sizeof(QEMUFileSocket));
		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;
		}

		QEMUFile qemu_fopen(const char filename, const char *mode)
		{
		QEMUFileStdio *s;

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

		s = g_malloc0(sizeof(QEMUFileStdio));

		s->stdio_file = fopen(filename, mode);
		if (!s->stdio_file) {
		goto fail;
		}

		if (mode[0] == 'w') {
		s->file = qemu_fopen_ops(s, &stdio_file_write_ops);
		} else {
		s->file = qemu_fopen_ops(s, &stdio_file_read_ops);
		}
		return s->file;
		fail:
		g_free(s);
		return NULL;
		}

		QEMUFile qemu_fopen_ops(void opaque, const QEMUFileOps *ops)
		{
		QEMUFile *f;

		f = g_malloc0(sizeof(QEMUFile));

		f->opaque = opaque;
		f->ops = ops;
		return f;
		}

		/*
		* Get last error for stream f
		*
		* Return negative error value if there has been an error on previous
		* operations, return 0 if no error happened.
		*
		*/
		int qemu_file_get_error(QEMUFile *f)
		{
		return f->last_error;
		}

		void qemu_file_set_error(QEMUFile *f, int ret)
		{
		if (f->last_error == 0) {
		f->last_error = ret;
		}
		}

		static inline bool qemu_file_is_writable(QEMUFile *f)
		{
		return f->ops->writev_buffer \|\| f->ops->put_buffer;
		}

		/**
		* Flushes QEMUFile buffer
		*
		* If there is writev_buffer QEMUFileOps it uses it otherwise uses
		* put_buffer ops.
		*/
		void qemu_fflush(QEMUFile *f)
		{
		ssize_t ret = 0;

		if (!qemu_file_is_writable(f)) {
		return;
		}

		if (f->ops->writev_buffer) {
		if (f->iovcnt > 0) {
		ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
		}
		} else {
		if (f->buf_index > 0) {
		ret = f->ops->put_buffer(f->opaque, f->buf, f->pos, f->buf_index);
		}
		}
		if (ret >= 0) {
		f->pos += ret;
		}
		f->buf_index = 0;
		f->iovcnt = 0;
		if (ret < 0) {
		qemu_file_set_error(f, ret);
		}
		}

		void ram_control_before_iterate(QEMUFile *f, uint64_t flags)
		{
		int ret = 0;

		if (f->ops->before_ram_iterate) {
		ret = f->ops->before_ram_iterate(f, f->opaque, flags);
		if (ret < 0) {
		qemu_file_set_error(f, ret);
		}
		}
		}

		void ram_control_after_iterate(QEMUFile *f, uint64_t flags)
		{
		int ret = 0;

		if (f->ops->after_ram_iterate) {
		ret = f->ops->after_ram_iterate(f, f->opaque, flags);
		if (ret < 0) {
		qemu_file_set_error(f, ret);
		}
		}
		}

		void ram_control_load_hook(QEMUFile *f, uint64_t flags)
		{
		int ret = -EINVAL;

		if (f->ops->hook_ram_load) {
		ret = f->ops->hook_ram_load(f, f->opaque, flags);
		if (ret < 0) {
		qemu_file_set_error(f, ret);
		}
		} else {
		qemu_file_set_error(f, ret);
		}
		}

		size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
		ram_addr_t offset, size_t size, int *bytes_sent)
		{
		if (f->ops->save_page) {
		int ret = f->ops->save_page(f, f->opaque, block_offset,
		offset, size, bytes_sent);

		if (ret != RAM_SAVE_CONTROL_DELAYED) {
		if (bytes_sent && *bytes_sent > 0) {
		qemu_update_position(f, *bytes_sent);
		} else if (ret < 0) {
		qemu_file_set_error(f, ret);
		}
		}

		return ret;
		}

		return RAM_SAVE_CONTROL_NOT_SUPP;
		}

		static void qemu_fill_buffer(QEMUFile *f)
		{
		int len;
		int pending;

		assert(!qemu_file_is_writable(f));

		pending = f->buf_size - f->buf_index;
		if (pending > 0) {
		memmove(f->buf, f->buf + f->buf_index, pending);
		}
		f->buf_index = 0;
		f->buf_size = pending;

		len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,
		IO_BUF_SIZE - pending);
		if (len > 0) {
		f->buf_size += len;
		f->pos += len;
		} else if (len == 0) {
		qemu_file_set_error(f, -EIO);
		} else if (len != -EAGAIN) {
		qemu_file_set_error(f, len);
		}
		}

		int qemu_get_fd(QEMUFile *f)
		{
		if (f->ops->get_fd) {
		return f->ops->get_fd(f->opaque);
		}
		return -1;
		}

		void qemu_update_position(QEMUFile *f, size_t size)
		{
		f->pos += size;
		}

		/** Closes the file
		*
		* Returns negative error value if any error happened on previous operations or
		* while closing the file. Returns 0 or positive number on success.
		*
		* The meaning of return value on success depends on the specific backend
		* being used.
		*/
		int qemu_fclose(QEMUFile *f)
		{
		int ret;
		qemu_fflush(f);
		ret = qemu_file_get_error(f);

		if (f->ops->close) {
		int ret2 = f->ops->close(f->opaque);
		if (ret >= 0) {
		ret = ret2;
		}
		}
		/* If any error was spotted before closing, we should report it
		* instead of the close() return value.
		*/
		if (f->last_error) {
		ret = f->last_error;
		}
		g_free(f);
		return ret;
		}

		static void add_to_iovec(QEMUFile f, const uint8_t buf, int size)
		{
		/* check for adjacent buffer and coalesce them */
		if (f->iovcnt > 0 && buf == f->iov[f->iovcnt - 1].iov_base +
		f->iov[f->iovcnt - 1].iov_len) {
		f->iov[f->iovcnt - 1].iov_len += size;
		} else {
		f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
		f->iov[f->iovcnt++].iov_len = size;
		}

		if (f->iovcnt >= MAX_IOV_SIZE) {
		qemu_fflush(f);
		}
		}

		void qemu_put_buffer_async(QEMUFile f, const uint8_t buf, int size)
		{
		if (!f->ops->writev_buffer) {
		qemu_put_buffer(f, buf, size);
		return;
		}

		if (f->last_error) {
		return;
		}

		f->bytes_xfer += size;
		add_to_iovec(f, buf, size);
		}

		void qemu_put_buffer(QEMUFile f, const uint8_t buf, int size)
		{
		int l;

		if (f->last_error) {
		return;
		}

		while (size > 0) {
		l = IO_BUF_SIZE - f->buf_index;
		if (l > size) {
		l = size;
		}
		memcpy(f->buf + f->buf_index, buf, l);
		f->bytes_xfer += l;
		if (f->ops->writev_buffer) {
		add_to_iovec(f, f->buf + f->buf_index, l);
		}
		f->buf_index += l;
		if (f->buf_index == IO_BUF_SIZE) {
		qemu_fflush(f);
		}
		if (qemu_file_get_error(f)) {
		break;
		}
		buf += l;
		size -= l;
		}
		}

		void qemu_put_byte(QEMUFile *f, int v)
		{
		if (f->last_error) {
		return;
		}

		f->buf[f->buf_index] = v;
		f->bytes_xfer++;
		if (f->ops->writev_buffer) {
		add_to_iovec(f, f->buf + f->buf_index, 1);
		}
		f->buf_index++;
		if (f->buf_index == IO_BUF_SIZE) {
		qemu_fflush(f);
		}
		}

		void qemu_file_skip(QEMUFile *f, int size)
		{
		if (f->buf_index + size <= f->buf_size) {
		f->buf_index += size;
		}
		}

		int qemu_peek_buffer(QEMUFile f, uint8_t buf, int size, size_t offset)
		{
		int pending;
		int index;

		assert(!qemu_file_is_writable(f));

		index = f->buf_index + offset;
		pending = f->buf_size - index;
		if (pending < size) {
		qemu_fill_buffer(f);
		index = f->buf_index + offset;
		pending = f->buf_size - index;
		}

		if (pending <= 0) {
		return 0;
		}
		if (size > pending) {
		size = pending;
		}

		memcpy(buf, f->buf + index, size);
		return size;
		}

		int qemu_get_buffer(QEMUFile f, uint8_t buf, int size)
		{
		int pending = size;
		int done = 0;

		while (pending > 0) {
		int res;

		res = qemu_peek_buffer(f, buf, pending, 0);
		if (res == 0) {
		return done;
		}
		qemu_file_skip(f, res);
		buf += res;
		pending -= res;
		done += res;
		}
		return done;
		}

		int qemu_peek_byte(QEMUFile *f, int offset)
		{
		int index = f->buf_index + offset;

		assert(!qemu_file_is_writable(f));

		if (index >= f->buf_size) {
		qemu_fill_buffer(f);
		index = f->buf_index + offset;
		if (index >= f->buf_size) {
		return 0;
		}
		}
		return f->buf[index];
		}

		int qemu_get_byte(QEMUFile *f)
		{
		int result;

		result = qemu_peek_byte(f, 0);
		qemu_file_skip(f, 1);
		return result;
		}

		int64_t qemu_ftell(QEMUFile *f)
		{
		qemu_fflush(f);
		return f->pos;
		}

		int qemu_file_rate_limit(QEMUFile *f)
		{
		if (qemu_file_get_error(f)) {
		return 1;
		}
		if (f->xfer_limit > 0 && f->bytes_xfer > f->xfer_limit) {
		return 1;
		}
		return 0;
		}

		int64_t qemu_file_get_rate_limit(QEMUFile *f)
		{
		return f->xfer_limit;
		}

		void qemu_file_set_rate_limit(QEMUFile *f, int64_t limit)
		{
		f->xfer_limit = limit;
		}

		void qemu_file_reset_rate_limit(QEMUFile *f)
		{
		f->bytes_xfer = 0;
		}

		void qemu_put_be16(QEMUFile *f, unsigned int v)
		{
		qemu_put_byte(f, v >> 8);
		qemu_put_byte(f, v);
		}

		void qemu_put_be32(QEMUFile *f, unsigned int v)
		{
		qemu_put_byte(f, v >> 24);
		qemu_put_byte(f, v >> 16);
		qemu_put_byte(f, v >> 8);
		qemu_put_byte(f, v);
		}

		void qemu_put_be64(QEMUFile *f, uint64_t v)
		{
		qemu_put_be32(f, v >> 32);
		qemu_put_be32(f, v);
		}

		unsigned int qemu_get_be16(QEMUFile *f)
		{
		unsigned int v;
		v = qemu_get_byte(f) << 8;
		v \|= qemu_get_byte(f);
		return v;
		}

		unsigned int qemu_get_be32(QEMUFile *f)
		{
		unsigned int v;
		v = qemu_get_byte(f) << 24;
		v \|= qemu_get_byte(f) << 16;
		v \|= qemu_get_byte(f) << 8;
		v \|= qemu_get_byte(f);
		return v;
		}

		uint64_t qemu_get_be64(QEMUFile *f)
		{
		uint64_t v;
		v = (uint64_t)qemu_get_be32(f) << 32;
		v \|= qemu_get_be32(f);
		return v;
		}

savevm.c

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