3e80bf9351
Rename arguments and use size_t for sizes instead of int,
from
int
qemu_sendv(int sockfd, struct iovec *iov,
int len, int iov_offset)
to
ssize_t
iov_send(int sockfd, struct iovec *iov,
size_t offset, size_t bytes)
The main motivation was to make it clear that length
and offset are in _bytes_, not in iov elements: it was
very confusing before, because all standard functions
which deals with iovecs expects number of iovs, not
bytes, even the fact that struct iovec has iov_len and
iov_ prefix does not help. With "bytes" and "offset",
especially since they're now size_t, it is much more
explicit. Also change the return type to be ssize_t
instead of int.
This also changes it to match other iov-related functons,
but not _quite_: there's still no argument indicating
where iovec ends, ie, no iov_cnt parameter as used
in iov_size() and friends. If will be added in subsequent
patch/rewrite.
All callers of qemu_sendv() and qemu_recvv() and
related, like qemu_co_sendv() and qemu_co_recvv(),
were checked to verify that it is safe to use unsigned
datatype instead of int.
Note that the order of arguments is changed to: offset
and bytes (len and iov_offset) are swapped with each
other. This is to make them consistent with very similar
functions from qemu_iovec family, where offset always
follows qiov, to mean the place in it to start from.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
82 lines
3.2 KiB
C
82 lines
3.2 KiB
C
/*
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* Helpers for using (partial) iovecs.
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*
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* Copyright (C) 2010 Red Hat, Inc.
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*
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* Author(s):
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* Amit Shah <amit.shah@redhat.com>
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* Michael Tokarev <mjt@tls.msk.ru>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include "qemu-common.h"
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/**
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* count and return data size, in bytes, of an iovec
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* starting at `iov' of `iov_cnt' number of elements.
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*/
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size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt);
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/**
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* Copy from single continuous buffer to scatter-gather vector of buffers
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* (iovec) and back like memcpy() between two continuous memory regions.
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* Data in single continuous buffer starting at address `buf' and
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* `bytes' bytes long will be copied to/from an iovec `iov' with
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* `iov_cnt' number of elements, starting at byte position `offset'
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* within the iovec. If the iovec does not contain enough space,
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* only part of data will be copied, up to the end of the iovec.
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* Number of bytes actually copied will be returned, which is
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* min(bytes, iov_size(iov)-offset)
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* `Offset' must point to the inside of iovec.
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* It is okay to use very large value for `bytes' since we're
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* limited by the size of the iovec anyway, provided that the
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* buffer pointed to by buf has enough space. One possible
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* such "large" value is -1 (sinice size_t is unsigned),
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* so specifying `-1' as `bytes' means 'up to the end of iovec'.
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*/
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size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
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size_t offset, const void *buf, size_t bytes);
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size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
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size_t offset, void *buf, size_t bytes);
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/**
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* Set data bytes pointed out by iovec `iov' of size `iov_cnt' elements,
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* starting at byte offset `start', to value `fillc', repeating it
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* `bytes' number of times. `Offset' must point to the inside of iovec.
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* If `bytes' is large enough, only last bytes portion of iovec,
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* up to the end of it, will be filled with the specified value.
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* Function return actual number of bytes processed, which is
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* min(size, iov_size(iov) - offset).
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* Again, it is okay to use large value for `bytes' to mean "up to the end".
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*/
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size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
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size_t offset, int fillc, size_t bytes);
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/*
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* Send/recv data from/to iovec buffers directly
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*
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* `offset' bytes in the beginning of iovec buffer are skipped and
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* next `bytes' bytes are used, which must be within data of iovec.
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*
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* r = iov_send(sockfd, iov, offset, bytes);
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*
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* is logically equivalent to
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*
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* char *buf = malloc(bytes);
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* iov_to_buf(iov, iovcnt, offset, buf, bytes);
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* r = send(sockfd, buf, bytes, 0);
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* free(buf);
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*/
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ssize_t iov_recv(int sockfd, struct iovec *iov, size_t offset, size_t bytes);
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ssize_t iov_send(int sockfd, struct iovec *iov, size_t offset, size_t bytes);
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/**
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* Produce a text hexdump of iovec `iov' with `iov_cnt' number of elements
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* in file `fp', prefixing each line with `prefix' and processing not more
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* than `limit' data bytes.
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*/
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void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
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FILE *fp, const char *prefix, size_t limit);
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