1 files changed, 123 insertions, 0 deletions
diff --git a/serialise.c b/serialise.c
new file mode 100644
index 0000000..944e741
--- /dev/null
+++ b/serialise.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* PASST - Plug A Simple Socket Transport
+ *  for qemu/UNIX domain socket mode
+ *
+ * PASTA - Pack A Subtle Tap Abstraction
+ *  for network namespace/tap device mode
+ *
+ * serialise.c - Serialisation of data structures over bytestreams
+ *
+ * Copyright Red Hat
+ * Author: David Gibson <david@gibson.dropbear.id.au>
+ */
+
+#include <assert.h>
+#include <endian.h>
+#include <errno.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#include "serialise.h"
+
+/**
+ * read_all_buf() - Fill a whole buffer from a file descriptor
+ * @fd:		File descriptor
+ * @buf:	Pointer to base of buffer
+ * @len:	Length of buffer
+ *
+ * Return: 0 on success, -1 on error (with errno set)
+ *
+ * #syscalls read
+ */
+int read_all_buf(int fd, void *buf, size_t len)
+{
+	size_t left = len;
+	char *p = buf;
+
+	while (left) {
+		ssize_t rc;
+
+		assert(left <= len);
+
+		do
+			rc = read(fd, p, left);
+		while ((rc < 0) && errno == EINTR);
+
+		if (rc < 0)
+			return -1;
+
+		if (rc == 0) {
+			errno = ENODATA;
+			return -1;
+		}
+
+		p += rc;
+		left -= rc;
+	}
+	return 0;
+}
+
+/**
+ * write_all_buf() - write all of a buffer to an fd
+ * @fd:		File descriptor
+ * @buf:	Pointer to base of buffer
+ * @len:	Length of buffer
+ *
+ * Return: 0 on success, -1 on error (with errno set)
+ *
+ * #syscalls write
+ */
+int write_all_buf(int fd, const void *buf, size_t len)
+{
+	const char *p = buf;
+	size_t left = len;
+
+	while (left) {
+		ssize_t rc;
+
+		do
+			rc = write(fd, p, left);
+		while ((rc < 0) && errno == EINTR);
+
+		if (rc < 0)
+			return -1;
+
+		p += rc;
+		left -= rc;
+	}
+	return 0;
+}
+
+/**
+ * read_uXXX() - Receive a uXXX value from an fd
+ * @fd:		File descriptor to read from
+ * @valp:	Pointer to variable to update with read value
+ *
+ * Return: 0 on success, -1 on error
+ */
+/**
+ * write_uXXX() - Send a uXXX value to an fd
+ * @fd:		File descriptor to write to
+ * @val:	Value to send
+ *
+ * Return: 0 on success, -1 on error
+ */
+#define SERIALISE_UINT(bits)						\
+	int read_u##bits(int fd, uint##bits##_t *val)			\
+	{								\
+		uint##bits##_t beval;					\
+		if (read_all_buf(fd, &beval, sizeof(beval)) < 0)	\
+			return -1;					\
+		*val = be##bits##toh(beval);				\
+		return 0;						\
+	}								\
+	int write_u##bits(int fd, uint##bits##_t val)			\
+	{								\
+		uint##bits##_t beval = htobe##bits(val);		\
+		return write_all_buf(fd, &beval, sizeof(beval));	\
+	}
+
+SERIALISE_UINT(32)
+
+#undef SERIALISE_UINT