ceph: buffer decoding helpers

Helper for decoding into a ceph_buffer, and other misc decoding helpers
we will need.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/buffer.c

@@ -1,6 +1,7 @@
 
 #include "ceph_debug.h"
 #include "buffer.h"
+#include "decode.h"
 
 struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
 {
@@ -59,3 +60,19 @@ int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp)
 	return 0;
 }
 
+int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end)
+{
+	size_t len;
+
+	ceph_decode_need(p, end, sizeof(u32), bad);
+	len = ceph_decode_32(p);
+	dout("decode_buffer len %d\n", (int)len);
+	ceph_decode_need(p, end, len, bad);
+	*b = ceph_buffer_new(len, GFP_NOFS);
+	if (!*b)
+		return -ENOMEM;
+	ceph_decode_copy(p, (*b)->vec.iov_base, len);
+	return 0;
+bad:
+	return -EINVAL;
+}

fs/ceph/buffer.h

@@ -34,4 +34,6 @@ static inline void ceph_buffer_put(struct ceph_buffer *b)
 	kref_put(&b->kref, ceph_buffer_release);
 }
 
+extern int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end);
+
 #endif

fs/ceph/decode.h

@@ -2,6 +2,7 @@
 #define __CEPH_DECODE_H
 
 #include <asm/unaligned.h>
+#include <linux/time.h>
 
 #include "types.h"
 
@@ -65,6 +66,11 @@ static inline void ceph_decode_copy(void **p, void *pv, size_t n)
 		ceph_decode_need(p, end, sizeof(u16), bad);	\
 		v = ceph_decode_16(p);				\
 	} while (0)
+#define ceph_decode_8_safe(p, end, v, bad)			\
+	do {							\
+		ceph_decode_need(p, end, sizeof(u8), bad);	\
+		v = ceph_decode_8(p);				\
+	} while (0)
 
 #define ceph_decode_copy_safe(p, end, pv, n, bad)		\
 	do {							\
@@ -156,5 +162,33 @@ static inline void ceph_encode_string(void **p, void *end,
 	*p += len;
 }
 
+#define ceph_encode_need(p, end, n, bad)		\
+	do {						\
+		if (unlikely(*(p) + (n) > (end))) 	\
+			goto bad;			\
+	} while (0)
+
+#define ceph_encode_64_safe(p, end, v, bad)			\
+	do {							\
+		ceph_encode_need(p, end, sizeof(u64), bad);	\
+		ceph_encode_64(p, v);				\
+	} while (0)
+#define ceph_encode_32_safe(p, end, v, bad)			\
+	do {							\
+		ceph_encode_need(p, end, sizeof(u32), bad);	\
+		ceph_encode_32(p, v);			\
+	} while (0)
+#define ceph_encode_16_safe(p, end, v, bad)			\
+	do {							\
+		ceph_encode_need(p, end, sizeof(u16), bad);	\
+		ceph_encode_16(p, v);			\
+	} while (0)
+
+#define ceph_encode_copy_safe(p, end, pv, n, bad)		\
+	do {							\
+		ceph_encode_need(p, end, n, bad);		\
+		ceph_encode_copy(p, pv, n);			\
+	} while (0)
+
 
 #endif