/* * Helpers for getting linearized buffers from iov / filling buffers into iovs * * Copyright IBM, Corp. 2007, 2008 * Copyright (C) 2010 Red Hat, Inc. * * Author(s): * Anthony Liguori <aliguori@us.ibm.com> * Amit Shah <amit.shah@redhat.com> * Michael Tokarev <mjt@tls.msk.ru> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. */ #include "iov.h" #ifdef _WIN32 # include <windows.h> # include <winsock2.h> #else # include <sys/types.h> # include <sys/socket.h> #endif size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt, size_t offset, const void *buf, size_t bytes) { size_t done; unsigned int i; for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { if (offset < iov[i].iov_len) { size_t len = MIN(iov[i].iov_len - offset, bytes - done); memcpy(iov[i].iov_base + offset, buf + done, len); done += len; offset = 0; } else { offset -= iov[i].iov_len; } } assert(offset == 0); return done; } size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt, size_t offset, void *buf, size_t bytes) { size_t done; unsigned int i; for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { if (offset < iov[i].iov_len) { size_t len = MIN(iov[i].iov_len - offset, bytes - done); memcpy(buf + done, iov[i].iov_base + offset, len); done += len; offset = 0; } else { offset -= iov[i].iov_len; } } assert(offset == 0); return done; } size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt, size_t offset, int fillc, size_t bytes) { size_t done; unsigned int i; for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { if (offset < iov[i].iov_len) { size_t len = MIN(iov[i].iov_len - offset, bytes - done); memset(iov[i].iov_base + offset, fillc, len); done += len; offset = 0; } else { offset -= iov[i].iov_len; } } assert(offset == 0); return done; } size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt) { size_t len; unsigned int i; len = 0; for (i = 0; i < iov_cnt; i++) { len += iov[i].iov_len; } return len; } /* helper function for iov_send_recv() */ static ssize_t do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send) { #if defined CONFIG_IOVEC && defined CONFIG_POSIX ssize_t ret; struct msghdr msg; memset(&msg, 0, sizeof(msg)); msg.msg_iov = iov; msg.msg_iovlen = iov_cnt; do { ret = do_send ? sendmsg(sockfd, &msg, 0) : recvmsg(sockfd, &msg, 0); } while (ret < 0 && errno == EINTR); return ret; #else /* else send piece-by-piece */ /*XXX Note: windows has WSASend() and WSARecv() */ unsigned i = 0; ssize_t ret = 0; while (i < iov_cnt) { ssize_t r = do_send ? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0) : recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0); if (r > 0) { ret += r; } else if (!r) { break; } else if (errno == EINTR) { continue; } else { /* else it is some "other" error, * only return if there was no data processed. */ if (ret == 0) { ret = -1; } break; } i++; } return ret; #endif } ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, size_t offset, size_t bytes, bool do_send) { ssize_t ret; unsigned si, ei; /* start and end indexes */ if (bytes == 0) { /* Catch the do-nothing case early, as otherwise we will pass an * empty iovec to sendmsg/recvmsg(), and not all implementations * accept this. */ return 0; } /* Find the start position, skipping `offset' bytes: * first, skip all full-sized vector elements, */ for (si = 0; si < iov_cnt && offset >= iov[si].iov_len; ++si) { offset -= iov[si].iov_len; } if (offset) { assert(si < iov_cnt); /* second, skip `offset' bytes from the (now) first element, * undo it on exit */ iov[si].iov_base += offset; iov[si].iov_len -= offset; } /* Find the end position skipping `bytes' bytes: */ /* first, skip all full-sized elements */ for (ei = si; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) { bytes -= iov[ei].iov_len; } if (bytes) { /* second, fixup the last element, and remember * the length we've cut from the end of it in `bytes' */ size_t tail; assert(ei < iov_cnt); assert(iov[ei].iov_len > bytes); tail = iov[ei].iov_len - bytes; iov[ei].iov_len = bytes; bytes = tail; /* bytes is now equal to the tail size */ ++ei; } ret = do_send_recv(sockfd, iov + si, ei - si, do_send); /* Undo the changes above */ if (offset) { iov[si].iov_base -= offset; iov[si].iov_len += offset; } if (bytes) { iov[ei-1].iov_len += bytes; } return ret; } void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, FILE *fp, const char *prefix, size_t limit) { unsigned int i, v, b; uint8_t *c; c = iov[0].iov_base; for (i = 0, v = 0, b = 0; b < limit; i++, b++) { if (i == iov[v].iov_len) { i = 0; v++; if (v == iov_cnt) { break; } c = iov[v].iov_base; } if ((b % 16) == 0) { fprintf(fp, "%s: %04x:", prefix, b); } if ((b % 4) == 0) { fprintf(fp, " "); } fprintf(fp, " %02x", c[i]); if ((b % 16) == 15) { fprintf(fp, "\n"); } } if ((b % 16) != 0) { fprintf(fp, "\n"); } }