[PATCH] v9fs: 9P protocol implementation

This part of the patch contains the 9P protocol functions.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 693 insertions, 0 deletions

diff --git a/fs/9p/conv.c b/fs/9p/conv.c
new file mode 100644
index 0000000..1554731
--- /dev/null
+++ b/fs/9p/conv.c
@@ -0,0 +1,693 @@
+/*
+ * linux/fs/9p/conv.c
+ *
+ * 9P protocol conversion functions
+ *
+ *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "conv.h"
+
+/*
+ * Buffer to help with string parsing
+ */
+struct cbuf {
+	unsigned char *sp;
+	unsigned char *p;
+	unsigned char *ep;
+};
+
+static inline void buf_init(struct cbuf *buf, void *data, int datalen)
+{
+	buf->sp = buf->p = data;
+	buf->ep = data + datalen;
+}
+
+static inline int buf_check_overflow(struct cbuf *buf)
+{
+	return buf->p > buf->ep;
+}
+
+static inline void buf_check_size(struct cbuf *buf, int len)
+{
+	if (buf->p+len > buf->ep) {
+		if (buf->p < buf->ep) {
+			eprintk(KERN_ERR, "buffer overflow\n");
+			buf->p = buf->ep + 1;
+		}
+	}
+}
+
+static inline void *buf_alloc(struct cbuf *buf, int len)
+{
+	void *ret = NULL;
+
+	buf_check_size(buf, len);
+	ret = buf->p;
+	buf->p += len;
+
+	return ret;
+}
+
+static inline void buf_put_int8(struct cbuf *buf, u8 val)
+{
+	buf_check_size(buf, 1);
+
+	buf->p[0] = val;
+	buf->p++;
+}
+
+static inline void buf_put_int16(struct cbuf *buf, u16 val)
+{
+	buf_check_size(buf, 2);
+
+	*(__le16 *) buf->p = cpu_to_le16(val);
+	buf->p += 2;
+}
+
+static inline void buf_put_int32(struct cbuf *buf, u32 val)
+{
+	buf_check_size(buf, 4);
+
+	*(__le32 *)buf->p = cpu_to_le32(val);
+	buf->p += 4;
+}
+
+static inline void buf_put_int64(struct cbuf *buf, u64 val)
+{
+	buf_check_size(buf, 8);
+
+	*(__le64 *)buf->p = cpu_to_le64(val);
+	buf->p += 8;
+}
+
+static inline void buf_put_stringn(struct cbuf *buf, const char *s, u16 slen)
+{
+	buf_check_size(buf, slen + 2);
+
+	buf_put_int16(buf, slen);
+	memcpy(buf->p, s, slen);
+	buf->p += slen;
+}
+
+static inline void buf_put_string(struct cbuf *buf, const char *s)
+{
+	buf_put_stringn(buf, s, strlen(s));
+}
+
+static inline void buf_put_data(struct cbuf *buf, void *data, u32 datalen)
+{
+	buf_check_size(buf, datalen);
+
+	memcpy(buf->p, data, datalen);
+	buf->p += datalen;
+}
+
+static inline u8 buf_get_int8(struct cbuf *buf)
+{
+	u8 ret = 0;
+
+	buf_check_size(buf, 1);
+	ret = buf->p[0];
+
+	buf->p++;
+
+	return ret;
+}
+
+static inline u16 buf_get_int16(struct cbuf *buf)
+{
+	u16 ret = 0;
+
+	buf_check_size(buf, 2);
+	ret = le16_to_cpu(*(__le16 *)buf->p);
+
+	buf->p += 2;
+
+	return ret;
+}
+
+static inline u32 buf_get_int32(struct cbuf *buf)
+{
+	u32 ret = 0;
+
+	buf_check_size(buf, 4);
+	ret = le32_to_cpu(*(__le32 *)buf->p);
+
+	buf->p += 4;
+
+	return ret;
+}
+
+static inline u64 buf_get_int64(struct cbuf *buf)
+{
+	u64 ret = 0;
+
+	buf_check_size(buf, 8);
+	ret = le64_to_cpu(*(__le64 *)buf->p);
+
+	buf->p += 8;
+
+	return ret;
+}
+
+static inline int
+buf_get_string(struct cbuf *buf, char *data, unsigned int datalen)
+{
+
+	u16 len = buf_get_int16(buf);
+	buf_check_size(buf, len);
+	if (len + 1 > datalen)
+		return 0;
+
+	memcpy(data, buf->p, len);
+	data[len] = 0;
+	buf->p += len;
+
+	return len + 1;
+}
+
+static inline char *buf_get_stringb(struct cbuf *buf, struct cbuf *sbuf)
+{
+	char *ret = NULL;
+	int n = buf_get_string(buf, sbuf->p, sbuf->ep - sbuf->p);
+
+	if (n > 0) {
+		ret = sbuf->p;
+		sbuf->p += n;
+	}
+
+	return ret;
+}
+
+static inline int buf_get_data(struct cbuf *buf, void *data, int datalen)
+{
+	buf_check_size(buf, datalen);
+
+	memcpy(data, buf->p, datalen);
+	buf->p += datalen;
+
+	return datalen;
+}
+
+static inline void *buf_get_datab(struct cbuf *buf, struct cbuf *dbuf,
+				  int datalen)
+{
+	char *ret = NULL;
+	int n = 0;
+
+	buf_check_size(dbuf, datalen);
+
+	n = buf_get_data(buf, dbuf->p, datalen);
+
+	if (n > 0) {
+		ret = dbuf->p;
+		dbuf->p += n;
+	}
+
+	return ret;
+}
+
+/**
+ * v9fs_size_stat - calculate the size of a variable length stat struct
+ * @v9ses: session information
+ * @stat: metadata (stat) structure
+ *
+ */
+
+static int v9fs_size_stat(struct v9fs_session_info *v9ses,
+			  struct v9fs_stat *stat)
+{
+	int size = 0;
+
+	if (stat == NULL) {
+		eprintk(KERN_ERR, "v9fs_size_stat: got a NULL stat pointer\n");
+		return 0;
+	}
+
+	size =			/* 2 + *//* size[2] */
+	    2 +			/* type[2] */
+	    4 +			/* dev[4] */
+	    1 +			/* qid.type[1] */
+	    4 +			/* qid.vers[4] */
+	    8 +			/* qid.path[8] */
+	    4 +			/* mode[4] */
+	    4 +			/* atime[4] */
+	    4 +			/* mtime[4] */
+	    8 +			/* length[8] */
+	    8;			/* minimum sum of string lengths */
+
+	if (stat->name)
+		size += strlen(stat->name);
+	if (stat->uid)
+		size += strlen(stat->uid);
+	if (stat->gid)
+		size += strlen(stat->gid);
+	if (stat->muid)
+		size += strlen(stat->muid);
+
+	if (v9ses->extended) {
+		size += 4 +	/* n_uid[4] */
+		    4 +		/* n_gid[4] */
+		    4 +		/* n_muid[4] */
+		    2;		/* string length of extension[4] */
+		if (stat->extension)
+			size += strlen(stat->extension);
+	}
+
+	return size;
+}
+
+/**
+ * serialize_stat - safely format a stat structure for transmission
+ * @v9ses: session info
+ * @stat: metadata (stat) structure
+ * @bufp: buffer to serialize structure into
+ *
+ */
+
+static int
+serialize_stat(struct v9fs_session_info *v9ses, struct v9fs_stat *stat,
+	       struct cbuf *bufp)
+{
+	buf_put_int16(bufp, stat->size);
+	buf_put_int16(bufp, stat->type);
+	buf_put_int32(bufp, stat->dev);
+	buf_put_int8(bufp, stat->qid.type);
+	buf_put_int32(bufp, stat->qid.version);
+	buf_put_int64(bufp, stat->qid.path);
+	buf_put_int32(bufp, stat->mode);
+	buf_put_int32(bufp, stat->atime);
+	buf_put_int32(bufp, stat->mtime);
+	buf_put_int64(bufp, stat->length);
+
+	buf_put_string(bufp, stat->name);
+	buf_put_string(bufp, stat->uid);
+	buf_put_string(bufp, stat->gid);
+	buf_put_string(bufp, stat->muid);
+
+	if (v9ses->extended) {
+		buf_put_string(bufp, stat->extension);
+		buf_put_int32(bufp, stat->n_uid);
+		buf_put_int32(bufp, stat->n_gid);
+		buf_put_int32(bufp, stat->n_muid);
+	}
+
+	if (buf_check_overflow(bufp))
+		return 0;
+
+	return stat->size;
+}
+
+/**
+ * deserialize_stat - safely decode a recieved metadata (stat) structure
+ * @v9ses: session info
+ * @bufp: buffer to deserialize
+ * @stat: metadata (stat) structure
+ * @dbufp: buffer to deserialize variable strings into
+ *
+ */
+
+static inline int
+deserialize_stat(struct v9fs_session_info *v9ses, struct cbuf *bufp,
+		 struct v9fs_stat *stat, struct cbuf *dbufp)
+{
+
+	stat->size = buf_get_int16(bufp);
+	stat->type = buf_get_int16(bufp);
+	stat->dev = buf_get_int32(bufp);
+	stat->qid.type = buf_get_int8(bufp);
+	stat->qid.version = buf_get_int32(bufp);
+	stat->qid.path = buf_get_int64(bufp);
+	stat->mode = buf_get_int32(bufp);
+	stat->atime = buf_get_int32(bufp);
+	stat->mtime = buf_get_int32(bufp);
+	stat->length = buf_get_int64(bufp);
+	stat->name = buf_get_stringb(bufp, dbufp);
+	stat->uid = buf_get_stringb(bufp, dbufp);
+	stat->gid = buf_get_stringb(bufp, dbufp);
+	stat->muid = buf_get_stringb(bufp, dbufp);
+
+	if (v9ses->extended) {
+		stat->extension = buf_get_stringb(bufp, dbufp);
+		stat->n_uid = buf_get_int32(bufp);
+		stat->n_gid = buf_get_int32(bufp);
+		stat->n_muid = buf_get_int32(bufp);
+	}
+
+	if (buf_check_overflow(bufp) || buf_check_overflow(dbufp))
+		return 0;
+
+	return stat->size + 2;
+}
+
+/**
+ * deserialize_statb - wrapper for decoding a received metadata structure
+ * @v9ses: session info
+ * @bufp: buffer to deserialize
+ * @dbufp: buffer to deserialize variable strings into
+ *
+ */
+
+static inline struct v9fs_stat *deserialize_statb(struct v9fs_session_info
+						  *v9ses, struct cbuf *bufp,
+						  struct cbuf *dbufp)
+{
+	struct v9fs_stat *ret = buf_alloc(dbufp, sizeof(struct v9fs_stat));
+
+	if (ret) {
+		int n = deserialize_stat(v9ses, bufp, ret, dbufp);
+		if (n <= 0)
+			return NULL;
+	}
+
+	return ret;
+}
+
+/**
+ * v9fs_deserialize_stat - decode a received metadata structure
+ * @v9ses: session info
+ * @buf: buffer to deserialize
+ * @buflen: length of received buffer
+ * @stat: metadata structure to decode into
+ * @statlen: length of destination metadata structure
+ *
+ */
+
+int
+v9fs_deserialize_stat(struct v9fs_session_info *v9ses, void *buf,
+		      u32 buflen, struct v9fs_stat *stat, u32 statlen)
+{
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+	struct cbuf dbuffer;
+	struct cbuf *dbufp = &dbuffer;
+
+	buf_init(bufp, buf, buflen);
+	buf_init(dbufp, (char *)stat + sizeof(struct v9fs_stat),
+		 statlen - sizeof(struct v9fs_stat));
+
+	return deserialize_stat(v9ses, bufp, stat, dbufp);
+}
+
+static inline int
+v9fs_size_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall)
+{
+	int size = 4 + 1 + 2;	/* size[4] msg[1] tag[2] */
+	int i = 0;
+
+	switch (fcall->id) {
+	default:
+		eprintk(KERN_ERR, "bad msg type %d\n", fcall->id);
+		return 0;
+	case TVERSION:		/* msize[4] version[s] */
+		size += 4 + 2 + strlen(fcall->params.tversion.version);
+		break;
+	case TAUTH:		/* afid[4] uname[s] aname[s] */
+		size += 4 + 2 + strlen(fcall->params.tauth.uname) +
+		    2 + strlen(fcall->params.tauth.aname);
+		break;
+	case TFLUSH:		/* oldtag[2] */
+		size += 2;
+		break;
+	case TATTACH:		/* fid[4] afid[4] uname[s] aname[s] */
+		size += 4 + 4 + 2 + strlen(fcall->params.tattach.uname) +
+		    2 + strlen(fcall->params.tattach.aname);
+		break;
+	case TWALK:		/* fid[4] newfid[4] nwname[2] nwname*(wname[s]) */
+		size += 4 + 4 + 2;
+		/* now compute total for the array of names */
+		for (i = 0; i < fcall->params.twalk.nwname; i++)
+			size += 2 + strlen(fcall->params.twalk.wnames[i]);
+		break;
+	case TOPEN:		/* fid[4] mode[1] */
+		size += 4 + 1;
+		break;
+	case TCREATE:		/* fid[4] name[s] perm[4] mode[1] */
+		size += 4 + 2 + strlen(fcall->params.tcreate.name) + 4 + 1;
+		break;
+	case TREAD:		/* fid[4] offset[8] count[4] */
+		size += 4 + 8 + 4;
+		break;
+	case TWRITE:		/* fid[4] offset[8] count[4] data[count] */
+		size += 4 + 8 + 4 + fcall->params.twrite.count;
+		break;
+	case TCLUNK:		/* fid[4] */
+		size += 4;
+		break;
+	case TREMOVE:		/* fid[4] */
+		size += 4;
+		break;
+	case TSTAT:		/* fid[4] */
+		size += 4;
+		break;
+	case TWSTAT:		/* fid[4] stat[n] */
+		fcall->params.twstat.stat->size =
+		    v9fs_size_stat(v9ses, fcall->params.twstat.stat);
+		size += 4 + 2 + 2 + fcall->params.twstat.stat->size;
+	}
+	return size;
+}
+
+/*
+ * v9fs_serialize_fcall - marshall fcall struct into a packet
+ * @v9ses: session information
+ * @fcall: structure to convert
+ * @data: buffer to serialize fcall into
+ * @datalen: length of buffer to serialize fcall into
+ *
+ */
+
+int
+v9fs_serialize_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall,
+		     void *data, u32 datalen)
+{
+	int i = 0;
+	struct v9fs_stat *stat = NULL;
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+
+	buf_init(bufp, data, datalen);
+
+	if (!fcall) {
+		eprintk(KERN_ERR, "no fcall\n");
+		return -EINVAL;
+	}
+
+	fcall->size = v9fs_size_fcall(v9ses, fcall);
+
+	buf_put_int32(bufp, fcall->size);
+	buf_put_int8(bufp, fcall->id);
+	buf_put_int16(bufp, fcall->tag);
+
+	dprintk(DEBUG_CONV, "size %d id %d tag %d\n", fcall->size, fcall->id,
+		fcall->tag);
+
+	/* now encode it */
+	switch (fcall->id) {
+	default:
+		eprintk(KERN_ERR, "bad msg type: %d\n", fcall->id);
+		return -EPROTO;
+	case TVERSION:
+		buf_put_int32(bufp, fcall->params.tversion.msize);
+		buf_put_string(bufp, fcall->params.tversion.version);
+		break;
+	case TAUTH:
+		buf_put_int32(bufp, fcall->params.tauth.afid);
+		buf_put_string(bufp, fcall->params.tauth.uname);
+		buf_put_string(bufp, fcall->params.tauth.aname);
+		break;
+	case TFLUSH:
+		buf_put_int16(bufp, fcall->params.tflush.oldtag);
+		break;
+	case TATTACH:
+		buf_put_int32(bufp, fcall->params.tattach.fid);
+		buf_put_int32(bufp, fcall->params.tattach.afid);
+		buf_put_string(bufp, fcall->params.tattach.uname);
+		buf_put_string(bufp, fcall->params.tattach.aname);
+		break;
+	case TWALK:
+		buf_put_int32(bufp, fcall->params.twalk.fid);
+		buf_put_int32(bufp, fcall->params.twalk.newfid);
+		buf_put_int16(bufp, fcall->params.twalk.nwname);
+		for (i = 0; i < fcall->params.twalk.nwname; i++)
+			buf_put_string(bufp, fcall->params.twalk.wnames[i]);
+		break;
+	case TOPEN:
+		buf_put_int32(bufp, fcall->params.topen.fid);
+		buf_put_int8(bufp, fcall->params.topen.mode);
+		break;
+	case TCREATE:
+		buf_put_int32(bufp, fcall->params.tcreate.fid);
+		buf_put_string(bufp, fcall->params.tcreate.name);
+		buf_put_int32(bufp, fcall->params.tcreate.perm);
+		buf_put_int8(bufp, fcall->params.tcreate.mode);
+		break;
+	case TREAD:
+		buf_put_int32(bufp, fcall->params.tread.fid);
+		buf_put_int64(bufp, fcall->params.tread.offset);
+		buf_put_int32(bufp, fcall->params.tread.count);
+		break;
+	case TWRITE:
+		buf_put_int32(bufp, fcall->params.twrite.fid);
+		buf_put_int64(bufp, fcall->params.twrite.offset);
+		buf_put_int32(bufp, fcall->params.twrite.count);
+		buf_put_data(bufp, fcall->params.twrite.data,
+			     fcall->params.twrite.count);
+		break;
+	case TCLUNK:
+		buf_put_int32(bufp, fcall->params.tclunk.fid);
+		break;
+	case TREMOVE:
+		buf_put_int32(bufp, fcall->params.tremove.fid);
+		break;
+	case TSTAT:
+		buf_put_int32(bufp, fcall->params.tstat.fid);
+		break;
+	case TWSTAT:
+		buf_put_int32(bufp, fcall->params.twstat.fid);
+		stat = fcall->params.twstat.stat;
+
+		buf_put_int16(bufp, stat->size + 2);
+		serialize_stat(v9ses, stat, bufp);
+		break;
+	}
+
+	if (buf_check_overflow(bufp))
+		return -EIO;
+
+	return fcall->size;
+}
+
+/**
+ * deserialize_fcall - unmarshal a response
+ * @v9ses: session information
+ * @msgsize: size of rcall message
+ * @buf: recieved buffer
+ * @buflen: length of received buffer
+ * @rcall: fcall structure to populate
+ * @rcalllen: length of fcall structure to populate
+ *
+ */
+
+int
+v9fs_deserialize_fcall(struct v9fs_session_info *v9ses, u32 msgsize,
+		       void *buf, u32 buflen, struct v9fs_fcall *rcall,
+		       int rcalllen)
+{
+
+	struct cbuf buffer;
+	struct cbuf *bufp = &buffer;
+	struct cbuf dbuffer;
+	struct cbuf *dbufp = &dbuffer;
+	int i = 0;
+
+	buf_init(bufp, buf, buflen);
+	buf_init(dbufp, (char *)rcall + sizeof(struct v9fs_fcall),
+		 rcalllen - sizeof(struct v9fs_fcall));
+
+	rcall->size = msgsize;
+	rcall->id = buf_get_int8(bufp);
+	rcall->tag = buf_get_int16(bufp);
+
+	dprintk(DEBUG_CONV, "size %d id %d tag %d\n", rcall->size, rcall->id,
+		rcall->tag);
+	switch (rcall->id) {
+	default:
+		eprintk(KERN_ERR, "unknown message type: %d\n", rcall->id);
+		return -EPROTO;
+	case RVERSION:
+		rcall->params.rversion.msize = buf_get_int32(bufp);
+		rcall->params.rversion.version = buf_get_stringb(bufp, dbufp);
+		break;
+	case RFLUSH:
+		break;
+	case RATTACH:
+		rcall->params.rattach.qid.type = buf_get_int8(bufp);
+		rcall->params.rattach.qid.version = buf_get_int32(bufp);
+		rcall->params.rattach.qid.path = buf_get_int64(bufp);
+		break;
+	case RWALK:
+		rcall->params.rwalk.nwqid = buf_get_int16(bufp);
+		rcall->params.rwalk.wqids = buf_alloc(bufp,
+		      rcall->params.rwalk.nwqid * sizeof(struct v9fs_qid));
+		if (rcall->params.rwalk.wqids)
+			for (i = 0; i < rcall->params.rwalk.nwqid; i++) {
+				rcall->params.rwalk.wqids[i].type =
+				    buf_get_int8(bufp);
+				rcall->params.rwalk.wqids[i].version =
+				    buf_get_int16(bufp);
+				rcall->params.rwalk.wqids[i].path =
+				    buf_get_int64(bufp);
+			}
+		break;
+	case ROPEN:
+		rcall->params.ropen.qid.type = buf_get_int8(bufp);
+		rcall->params.ropen.qid.version = buf_get_int32(bufp);
+		rcall->params.ropen.qid.path = buf_get_int64(bufp);
+		rcall->params.ropen.iounit = buf_get_int32(bufp);
+		break;
+	case RCREATE:
+		rcall->params.rcreate.qid.type = buf_get_int8(bufp);
+		rcall->params.rcreate.qid.version = buf_get_int32(bufp);
+		rcall->params.rcreate.qid.path = buf_get_int64(bufp);
+		rcall->params.rcreate.iounit = buf_get_int32(bufp);
+		break;
+	case RREAD:
+		rcall->params.rread.count = buf_get_int32(bufp);
+		rcall->params.rread.data = buf_get_datab(bufp, dbufp,
+			rcall->params.rread.count);
+		break;
+	case RWRITE:
+		rcall->params.rwrite.count = buf_get_int32(bufp);
+		break;
+	case RCLUNK:
+		break;
+	case RREMOVE:
+		break;
+	case RSTAT:
+		buf_get_int16(bufp);
+		rcall->params.rstat.stat =
+		    deserialize_statb(v9ses, bufp, dbufp);
+		break;
+	case RWSTAT:
+		break;
+	case RERROR:
+		rcall->params.rerror.error = buf_get_stringb(bufp, dbufp);
+		if (v9ses->extended)
+			rcall->params.rerror.errno = buf_get_int16(bufp);
+		break;
+	}
+
+	if (buf_check_overflow(bufp) || buf_check_overflow(dbufp))
+		return -EIO;
+
+	return rcall->size;
+}