This adds a new utility routine which will return a dynamically- allocated buffer containing a string that has been decoded from ceph over-the-wire format. It also returns the length of the string if the address of a size variable is supplied to receive it.
Signed-off-by: Alex Elder <[email protected]> --- v2: Made the function safe from overrunning the source memory, and and added a gfp argument to pass to kmalloc() include/linux/ceph/decode.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) Index: b/include/linux/ceph/decode.h =================================================================== --- a/include/linux/ceph/decode.h +++ b/include/linux/ceph/decode.h @@ -130,6 +130,44 @@ bad: } /* + * Allocate a buffer big enough to hold the wire-encoded string, and + * decode the string into it. The resulting string will always be + * terminated with '\0'. If successful, *p will be advanced + * past the decoded data. Also, if lenp is not a null pointer, the + * length (not including the terminating '\0') will be recorded in + * it. Note that a zero-length string is a valid return value. + * + * Returns a pointer to the newly-allocated string buffer, or a null + * pointer if an error occurs. Neither "p" nor "end" will be updated + * if NULL is returned. + * + * There are two possible failures: + * - memory could not be allocated for the result + * - converting the string would require accessing memory at or + * beyond the "end" pointer provided + */ +static inline char *ceph_extract_encoded_string(void **p, void *end, + size_t *lenp, gfp_t gfp) +{ + ssize_t len; + char *buf; + + len = ceph_decode_string(p, end, NULL, 0); + if (len < 0) + return NULL; + + buf = kmalloc(len + 1, gfp); + if (!buf) + return NULL; + + (void) ceph_decode_string(p, end, buf, len + 1); + if (lenp) + *lenp = (size_t) len; + + return buf; +} + +/* * struct ceph_timespec <-> struct timespec */ static inline void ceph_decode_timespec(struct timespec *ts, -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
