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/* 9p/defs.h - TODO
*
* Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-Licence-Identifier: AGPL-3.0-or-later
*/
#ifndef _9P_DEFS_H_
#define _9P_DEFS_H_
#include <stdint.h>
#define P9_NOTAG ((uint16_t)~0U)
#define P9_NOFID ((uint32_t)~0U)
enum p9_version {
/* P9_VER_9P1, */
P9_VER_9P2000,
/*P9_VER_9P2000_u,*/
/*P9_VER_9P2000_L,*/
/*P9_VER_9P2000_e,*/
_P9_VER_CNT,
};
struct p9_ctx {
enum p9_version version;
uint32_t max_msg_size;
uint32_t err_num;
char err_msg[256]; /* I chose 256 arbitrarily. */
};
/** Write an static error into ctx, return -1. */
int p9_error(struct p9_ctx *ctx, uint32_t linux_errno, char const *msg);
/** Write a printf-style error into ctx, return -1. */
int p9_errorf(struct p9_ctx *ctx, uint32_t linux_errno, char const *fmt, ...);
/**
* Return how much space the message at net_bytes will take when
* unmarshaled. This number may be larger than net_bytes due to (1)
* struct padding, (2) nul-terminator byes for strings.
*
* Emits an error (return -1, set ctx->err_num and ctx->err_msg) if
* either the message type is unknown or if net_bytes is too short for
* that message type.
*
* @param net_bytes : the complete request, starting with the "size[4]"
* @return required size, or -1 on error
*/
size_t p9_unmarshal_size(struct p9_ctx *ctx, uint8_t *net_bytes);
/**
* Unmarshal the 9P message `net_bytes` into the C struct `out_body`.
*
* Emits an error (return 0, set ctx->err_num and ctx->err_msg) if a
* string contains invalid UTF-8 or a nul-byte.
*
* @param net_bytes : the complete message, starting with the "size[4]"
* @param out_tag : the message-ID tag
* @param out_body : the message body, must be at least p9_unmarshal_size() bytes
* @return the message type, or -1 on error
*/
uint8_t p9_unmarshal(struct p9_ctx *ctx, uint8_t *net_bytes, uint16_t *out_tag, void *out_body);
/**
* Marshal a `struct p9_msg_{type}` structure into a byte-array.
*
* @param struct p9_ctx *ctx : a request context
* @param uint16_t msgid : the message-ID tag
* @param struct p9_msg_{type} msg : the message to encode
*
* @param uint8_t *out_bytes : the buffer to encode to, must be at be at least ctx->max_msg_size bytes
* @return uint32_t : the encoded length, or -1 on error
*/
#define p9_marshal(ctx, msgid, msg, out_bytes) _p9_marshal(ctx, P9_TYPECODE_FOR_CTYPE(msg), msgid, &(msg), out_bytes)
uint32_t _p9_marshal(struct p9_ctx *ctx, uint8_t typ, uint16_t msgid, void *body, uint8_t *out_bytes);
#endif /* _9P_DEFS_H_ */
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