| /* |
| * 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 "qemu/iov.h" |
| #include "qemu/sockets.h" |
| |
| size_t iov_from_buf(const 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) |
| { |
| #ifdef 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 total = 0; |
| ssize_t ret; |
| size_t orig_len, tail; |
| unsigned niov; |
| |
| while (bytes > 0) { |
| /* Find the start position, skipping `offset' bytes: |
| * first, skip all full-sized vector elements, */ |
| for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) { |
| offset -= iov[niov].iov_len; |
| } |
| |
| /* niov == iov_cnt would only be valid if bytes == 0, which |
| * we already ruled out in the loop condition. */ |
| assert(niov < iov_cnt); |
| iov += niov; |
| iov_cnt -= niov; |
| |
| if (offset) { |
| /* second, skip `offset' bytes from the (now) first element, |
| * undo it on exit */ |
| iov[0].iov_base += offset; |
| iov[0].iov_len -= offset; |
| } |
| /* Find the end position skipping `bytes' bytes: */ |
| /* first, skip all full-sized elements */ |
| tail = bytes; |
| for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) { |
| tail -= iov[niov].iov_len; |
| } |
| if (tail) { |
| /* second, fixup the last element, and remember the original |
| * length */ |
| assert(niov < iov_cnt); |
| assert(iov[niov].iov_len > tail); |
| orig_len = iov[niov].iov_len; |
| iov[niov++].iov_len = tail; |
| ret = do_send_recv(sockfd, iov, niov, do_send); |
| /* Undo the changes above before checking for errors */ |
| iov[niov-1].iov_len = orig_len; |
| } else { |
| ret = do_send_recv(sockfd, iov, niov, do_send); |
| } |
| if (offset) { |
| iov[0].iov_base -= offset; |
| iov[0].iov_len += offset; |
| } |
| |
| if (ret < 0) { |
| assert(errno != EINTR); |
| if (errno == EAGAIN && total > 0) { |
| return total; |
| } |
| return -1; |
| } |
| |
| if (ret == 0 && !do_send) { |
| /* recv returns 0 when the peer has performed an orderly |
| * shutdown. */ |
| break; |
| } |
| |
| /* Prepare for the next iteration */ |
| offset += ret; |
| total += ret; |
| bytes -= ret; |
| } |
| |
| return total; |
| } |
| |
| |
| void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, |
| FILE *fp, const char *prefix, size_t limit) |
| { |
| int v; |
| size_t size = 0; |
| char *buf; |
| |
| for (v = 0; v < iov_cnt; v++) { |
| size += iov[v].iov_len; |
| } |
| size = size > limit ? limit : size; |
| buf = g_malloc(size); |
| iov_to_buf(iov, iov_cnt, 0, buf, size); |
| qemu_hexdump(buf, fp, prefix, size); |
| g_free(buf); |
| } |
| |
| unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, |
| const struct iovec *iov, unsigned int iov_cnt, |
| size_t offset, size_t bytes) |
| { |
| size_t len; |
| unsigned int i, j; |
| for (i = 0, j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) { |
| if (offset >= iov[i].iov_len) { |
| offset -= iov[i].iov_len; |
| continue; |
| } |
| len = MIN(bytes, iov[i].iov_len - offset); |
| |
| dst_iov[j].iov_base = iov[i].iov_base + offset; |
| dst_iov[j].iov_len = len; |
| j++; |
| bytes -= len; |
| offset = 0; |
| } |
| assert(offset == 0); |
| return j; |
| } |
| |
| /* io vectors */ |
| |
| void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint) |
| { |
| qiov->iov = g_malloc(alloc_hint * sizeof(struct iovec)); |
| qiov->niov = 0; |
| qiov->nalloc = alloc_hint; |
| qiov->size = 0; |
| } |
| |
| void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov) |
| { |
| int i; |
| |
| qiov->iov = iov; |
| qiov->niov = niov; |
| qiov->nalloc = -1; |
| qiov->size = 0; |
| for (i = 0; i < niov; i++) |
| qiov->size += iov[i].iov_len; |
| } |
| |
| void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) |
| { |
| assert(qiov->nalloc != -1); |
| |
| if (qiov->niov == qiov->nalloc) { |
| qiov->nalloc = 2 * qiov->nalloc + 1; |
| qiov->iov = g_realloc(qiov->iov, qiov->nalloc * sizeof(struct iovec)); |
| } |
| qiov->iov[qiov->niov].iov_base = base; |
| qiov->iov[qiov->niov].iov_len = len; |
| qiov->size += len; |
| ++qiov->niov; |
| } |
| |
| /* |
| * Concatenates (partial) iovecs from src_iov to the end of dst. |
| * It starts copying after skipping `soffset' bytes at the |
| * beginning of src and adds individual vectors from src to |
| * dst copies up to `sbytes' bytes total, or up to the end |
| * of src_iov if it comes first. This way, it is okay to specify |
| * very large value for `sbytes' to indicate "up to the end |
| * of src". |
| * Only vector pointers are processed, not the actual data buffers. |
| */ |
| void qemu_iovec_concat_iov(QEMUIOVector *dst, |
| struct iovec *src_iov, unsigned int src_cnt, |
| size_t soffset, size_t sbytes) |
| { |
| int i; |
| size_t done; |
| |
| if (!sbytes) { |
| return; |
| } |
| assert(dst->nalloc != -1); |
| for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) { |
| if (soffset < src_iov[i].iov_len) { |
| size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done); |
| qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len); |
| done += len; |
| soffset = 0; |
| } else { |
| soffset -= src_iov[i].iov_len; |
| } |
| } |
| assert(soffset == 0); /* offset beyond end of src */ |
| } |
| |
| /* |
| * Concatenates (partial) iovecs from src to the end of dst. |
| * It starts copying after skipping `soffset' bytes at the |
| * beginning of src and adds individual vectors from src to |
| * dst copies up to `sbytes' bytes total, or up to the end |
| * of src if it comes first. This way, it is okay to specify |
| * very large value for `sbytes' to indicate "up to the end |
| * of src". |
| * Only vector pointers are processed, not the actual data buffers. |
| */ |
| void qemu_iovec_concat(QEMUIOVector *dst, |
| QEMUIOVector *src, size_t soffset, size_t sbytes) |
| { |
| qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes); |
| } |
| |
| /* |
| * Check if the contents of the iovecs are all zero |
| */ |
| bool qemu_iovec_is_zero(QEMUIOVector *qiov) |
| { |
| int i; |
| for (i = 0; i < qiov->niov; i++) { |
| size_t offs = QEMU_ALIGN_DOWN(qiov->iov[i].iov_len, 4 * sizeof(long)); |
| uint8_t *ptr = qiov->iov[i].iov_base; |
| if (offs && !buffer_is_zero(qiov->iov[i].iov_base, offs)) { |
| return false; |
| } |
| for (; offs < qiov->iov[i].iov_len; offs++) { |
| if (ptr[offs]) { |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| void qemu_iovec_destroy(QEMUIOVector *qiov) |
| { |
| assert(qiov->nalloc != -1); |
| |
| qemu_iovec_reset(qiov); |
| g_free(qiov->iov); |
| qiov->nalloc = 0; |
| qiov->iov = NULL; |
| } |
| |
| void qemu_iovec_reset(QEMUIOVector *qiov) |
| { |
| assert(qiov->nalloc != -1); |
| |
| qiov->niov = 0; |
| qiov->size = 0; |
| } |
| |
| size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset, |
| void *buf, size_t bytes) |
| { |
| return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes); |
| } |
| |
| size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset, |
| const void *buf, size_t bytes) |
| { |
| return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes); |
| } |
| |
| size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, |
| int fillc, size_t bytes) |
| { |
| return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes); |
| } |
| |
| /** |
| * Check that I/O vector contents are identical |
| * |
| * The IO vectors must have the same structure (same length of all parts). |
| * A typical usage is to compare vectors created with qemu_iovec_clone(). |
| * |
| * @a: I/O vector |
| * @b: I/O vector |
| * @ret: Offset to first mismatching byte or -1 if match |
| */ |
| ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b) |
| { |
| int i; |
| ssize_t offset = 0; |
| |
| assert(a->niov == b->niov); |
| for (i = 0; i < a->niov; i++) { |
| size_t len = 0; |
| uint8_t *p = (uint8_t *)a->iov[i].iov_base; |
| uint8_t *q = (uint8_t *)b->iov[i].iov_base; |
| |
| assert(a->iov[i].iov_len == b->iov[i].iov_len); |
| while (len < a->iov[i].iov_len && *p++ == *q++) { |
| len++; |
| } |
| |
| offset += len; |
| |
| if (len != a->iov[i].iov_len) { |
| return offset; |
| } |
| } |
| return -1; |
| } |
| |
| typedef struct { |
| int src_index; |
| struct iovec *src_iov; |
| void *dest_base; |
| } IOVectorSortElem; |
| |
| static int sortelem_cmp_src_base(const void *a, const void *b) |
| { |
| const IOVectorSortElem *elem_a = a; |
| const IOVectorSortElem *elem_b = b; |
| |
| /* Don't overflow */ |
| if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) { |
| return -1; |
| } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) { |
| return 1; |
| } else { |
| return 0; |
| } |
| } |
| |
| static int sortelem_cmp_src_index(const void *a, const void *b) |
| { |
| const IOVectorSortElem *elem_a = a; |
| const IOVectorSortElem *elem_b = b; |
| |
| return elem_a->src_index - elem_b->src_index; |
| } |
| |
| /** |
| * Copy contents of I/O vector |
| * |
| * The relative relationships of overlapping iovecs are preserved. This is |
| * necessary to ensure identical semantics in the cloned I/O vector. |
| */ |
| void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf) |
| { |
| IOVectorSortElem sortelems[src->niov]; |
| void *last_end; |
| int i; |
| |
| /* Sort by source iovecs by base address */ |
| for (i = 0; i < src->niov; i++) { |
| sortelems[i].src_index = i; |
| sortelems[i].src_iov = &src->iov[i]; |
| } |
| qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base); |
| |
| /* Allocate buffer space taking into account overlapping iovecs */ |
| last_end = NULL; |
| for (i = 0; i < src->niov; i++) { |
| struct iovec *cur = sortelems[i].src_iov; |
| ptrdiff_t rewind = 0; |
| |
| /* Detect overlap */ |
| if (last_end && last_end > cur->iov_base) { |
| rewind = last_end - cur->iov_base; |
| } |
| |
| sortelems[i].dest_base = buf - rewind; |
| buf += cur->iov_len - MIN(rewind, cur->iov_len); |
| last_end = MAX(cur->iov_base + cur->iov_len, last_end); |
| } |
| |
| /* Sort by source iovec index and build destination iovec */ |
| qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index); |
| for (i = 0; i < src->niov; i++) { |
| qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len); |
| } |
| } |
| |
| size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, |
| size_t bytes) |
| { |
| size_t total = 0; |
| struct iovec *cur; |
| |
| for (cur = *iov; *iov_cnt > 0; cur++) { |
| if (cur->iov_len > bytes) { |
| cur->iov_base += bytes; |
| cur->iov_len -= bytes; |
| total += bytes; |
| break; |
| } |
| |
| bytes -= cur->iov_len; |
| total += cur->iov_len; |
| *iov_cnt -= 1; |
| } |
| |
| *iov = cur; |
| return total; |
| } |
| |
| size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, |
| size_t bytes) |
| { |
| size_t total = 0; |
| struct iovec *cur; |
| |
| if (*iov_cnt == 0) { |
| return 0; |
| } |
| |
| cur = iov + (*iov_cnt - 1); |
| |
| while (*iov_cnt > 0) { |
| if (cur->iov_len > bytes) { |
| cur->iov_len -= bytes; |
| total += bytes; |
| break; |
| } |
| |
| bytes -= cur->iov_len; |
| total += cur->iov_len; |
| cur--; |
| *iov_cnt -= 1; |
| } |
| |
| return total; |
| } |