11de7afc9SPaolo Bonzini /* 21de7afc9SPaolo Bonzini * Helpers for using (partial) iovecs. 31de7afc9SPaolo Bonzini * 41de7afc9SPaolo Bonzini * Copyright (C) 2010 Red Hat, Inc. 51de7afc9SPaolo Bonzini * 61de7afc9SPaolo Bonzini * Author(s): 71de7afc9SPaolo Bonzini * Amit Shah <amit.shah@redhat.com> 81de7afc9SPaolo Bonzini * Michael Tokarev <mjt@tls.msk.ru> 91de7afc9SPaolo Bonzini * 101de7afc9SPaolo Bonzini * This work is licensed under the terms of the GNU GPL, version 2. See 111de7afc9SPaolo Bonzini * the COPYING file in the top-level directory. 121de7afc9SPaolo Bonzini */ 131de7afc9SPaolo Bonzini 141de7afc9SPaolo Bonzini #ifndef IOV_H 151de7afc9SPaolo Bonzini #define IOV_H 161de7afc9SPaolo Bonzini 171de7afc9SPaolo Bonzini #include "qemu-common.h" 181de7afc9SPaolo Bonzini 191de7afc9SPaolo Bonzini /** 201de7afc9SPaolo Bonzini * count and return data size, in bytes, of an iovec 211de7afc9SPaolo Bonzini * starting at `iov' of `iov_cnt' number of elements. 221de7afc9SPaolo Bonzini */ 231de7afc9SPaolo Bonzini size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt); 241de7afc9SPaolo Bonzini 251de7afc9SPaolo Bonzini /** 261de7afc9SPaolo Bonzini * Copy from single continuous buffer to scatter-gather vector of buffers 271de7afc9SPaolo Bonzini * (iovec) and back like memcpy() between two continuous memory regions. 281de7afc9SPaolo Bonzini * Data in single continuous buffer starting at address `buf' and 291de7afc9SPaolo Bonzini * `bytes' bytes long will be copied to/from an iovec `iov' with 301de7afc9SPaolo Bonzini * `iov_cnt' number of elements, starting at byte position `offset' 311de7afc9SPaolo Bonzini * within the iovec. If the iovec does not contain enough space, 321de7afc9SPaolo Bonzini * only part of data will be copied, up to the end of the iovec. 331de7afc9SPaolo Bonzini * Number of bytes actually copied will be returned, which is 341de7afc9SPaolo Bonzini * min(bytes, iov_size(iov)-offset) 351de7afc9SPaolo Bonzini * `Offset' must point to the inside of iovec. 361de7afc9SPaolo Bonzini * It is okay to use very large value for `bytes' since we're 371de7afc9SPaolo Bonzini * limited by the size of the iovec anyway, provided that the 381de7afc9SPaolo Bonzini * buffer pointed to by buf has enough space. One possible 391de7afc9SPaolo Bonzini * such "large" value is -1 (sinice size_t is unsigned), 401de7afc9SPaolo Bonzini * so specifying `-1' as `bytes' means 'up to the end of iovec'. 411de7afc9SPaolo Bonzini */ 421de7afc9SPaolo Bonzini size_t iov_from_buf(const struct iovec *iov, unsigned int iov_cnt, 431de7afc9SPaolo Bonzini size_t offset, const void *buf, size_t bytes); 441de7afc9SPaolo Bonzini size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt, 451de7afc9SPaolo Bonzini size_t offset, void *buf, size_t bytes); 461de7afc9SPaolo Bonzini 471de7afc9SPaolo Bonzini /** 481de7afc9SPaolo Bonzini * Set data bytes pointed out by iovec `iov' of size `iov_cnt' elements, 491de7afc9SPaolo Bonzini * starting at byte offset `start', to value `fillc', repeating it 501de7afc9SPaolo Bonzini * `bytes' number of times. `Offset' must point to the inside of iovec. 511de7afc9SPaolo Bonzini * If `bytes' is large enough, only last bytes portion of iovec, 521de7afc9SPaolo Bonzini * up to the end of it, will be filled with the specified value. 531de7afc9SPaolo Bonzini * Function return actual number of bytes processed, which is 541de7afc9SPaolo Bonzini * min(size, iov_size(iov) - offset). 551de7afc9SPaolo Bonzini * Again, it is okay to use large value for `bytes' to mean "up to the end". 561de7afc9SPaolo Bonzini */ 571de7afc9SPaolo Bonzini size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt, 581de7afc9SPaolo Bonzini size_t offset, int fillc, size_t bytes); 591de7afc9SPaolo Bonzini 601de7afc9SPaolo Bonzini /* 611de7afc9SPaolo Bonzini * Send/recv data from/to iovec buffers directly 621de7afc9SPaolo Bonzini * 631de7afc9SPaolo Bonzini * `offset' bytes in the beginning of iovec buffer are skipped and 641de7afc9SPaolo Bonzini * next `bytes' bytes are used, which must be within data of iovec. 651de7afc9SPaolo Bonzini * 661de7afc9SPaolo Bonzini * r = iov_send_recv(sockfd, iov, iovcnt, offset, bytes, true); 671de7afc9SPaolo Bonzini * 681de7afc9SPaolo Bonzini * is logically equivalent to 691de7afc9SPaolo Bonzini * 701de7afc9SPaolo Bonzini * char *buf = malloc(bytes); 711de7afc9SPaolo Bonzini * iov_to_buf(iov, iovcnt, offset, buf, bytes); 721de7afc9SPaolo Bonzini * r = send(sockfd, buf, bytes, 0); 731de7afc9SPaolo Bonzini * free(buf); 741de7afc9SPaolo Bonzini * 751de7afc9SPaolo Bonzini * For iov_send_recv() _whole_ area being sent or received 761de7afc9SPaolo Bonzini * should be within the iovec, not only beginning of it. 771de7afc9SPaolo Bonzini */ 781de7afc9SPaolo Bonzini ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, 791de7afc9SPaolo Bonzini size_t offset, size_t bytes, bool do_send); 801de7afc9SPaolo Bonzini #define iov_recv(sockfd, iov, iov_cnt, offset, bytes) \ 811de7afc9SPaolo Bonzini iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, false) 821de7afc9SPaolo Bonzini #define iov_send(sockfd, iov, iov_cnt, offset, bytes) \ 831de7afc9SPaolo Bonzini iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, true) 841de7afc9SPaolo Bonzini 851de7afc9SPaolo Bonzini /** 861de7afc9SPaolo Bonzini * Produce a text hexdump of iovec `iov' with `iov_cnt' number of elements 871de7afc9SPaolo Bonzini * in file `fp', prefixing each line with `prefix' and processing not more 881de7afc9SPaolo Bonzini * than `limit' data bytes. 891de7afc9SPaolo Bonzini */ 901de7afc9SPaolo Bonzini void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, 911de7afc9SPaolo Bonzini FILE *fp, const char *prefix, size_t limit); 921de7afc9SPaolo Bonzini 931de7afc9SPaolo Bonzini /* 941de7afc9SPaolo Bonzini * Partial copy of vector from iov to dst_iov (data is not copied). 951de7afc9SPaolo Bonzini * dst_iov overlaps iov at a specified offset. 961de7afc9SPaolo Bonzini * size of dst_iov is at most bytes. dst vector count is returned. 971de7afc9SPaolo Bonzini */ 981de7afc9SPaolo Bonzini unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, 991de7afc9SPaolo Bonzini const struct iovec *iov, unsigned int iov_cnt, 1001de7afc9SPaolo Bonzini size_t offset, size_t bytes); 1011de7afc9SPaolo Bonzini 102*d0277635SStefan Hajnoczi /* 103*d0277635SStefan Hajnoczi * Remove a given number of bytes from the front or back of a vector. 104*d0277635SStefan Hajnoczi * This may update iov and/or iov_cnt to exclude iovec elements that are 105*d0277635SStefan Hajnoczi * no longer required. 106*d0277635SStefan Hajnoczi * 107*d0277635SStefan Hajnoczi * The number of bytes actually discarded is returned. This number may be 108*d0277635SStefan Hajnoczi * smaller than requested if the vector is too small. 109*d0277635SStefan Hajnoczi */ 110*d0277635SStefan Hajnoczi size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, 111*d0277635SStefan Hajnoczi size_t bytes); 112*d0277635SStefan Hajnoczi size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, 113*d0277635SStefan Hajnoczi size_t bytes); 114*d0277635SStefan Hajnoczi 1151de7afc9SPaolo Bonzini #endif 116