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]> --- v3: Final version. Sage convinced me that there was no need for ceph_decode_string() other than its use in this function, so now this implements what that function had been doing directly. include/linux/ceph/decode.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) Index: b/include/linux/ceph/decode.h =================================================================== --- a/include/linux/ceph/decode.h +++ b/include/linux/ceph/decode.h @@ -85,6 +85,50 @@ static inline int ceph_has_room(void **p } while (0) /* + * 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 + * *lenp. 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 *lenp will have been + * updated if NULL is returned. + * + * There are two possible failures: + * - converting the string would require accessing memory at or + * beyond the "end" pointer provided + * - memory could not be allocated for the result + */ +static inline char *ceph_extract_encoded_string(void **p, void *end, + size_t *lenp, gfp_t gfp) +{ + u32 len; + void *sp = *p; + char *buf = NULL; + + ceph_decode_32_safe(&sp, end, len, out); + if (!ceph_has_room(&sp, end, len)) + return NULL; + + buf = kmalloc(len + 1, gfp); + if (!buf) + return NULL; + + if (len) + memcpy(buf, sp, len); + buf[len] = '\0'; + + *p = (char *) *p + sizeof (u32) + len; + + if (lenp) + *lenp = (size_t) len; +out: + 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
