1 files changed, 318 insertions, 0 deletions

diff --git a/fuse/buffer.c b/fuse/buffer.c
new file mode 100644
index 000000000..053e396bc
--- /dev/null
+++ b/fuse/buffer.c
@@ -0,0 +1,318 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2010  Miklos Szeredi <miklos@szeredi.hu>
+
+  This program can be distributed under the terms of the GNU LGPLv2.
+  See the file COPYING.LIB
+*/
+
+#define _GNU_SOURCE
+
+#include "config.h"
+#include "fuse_i.h"
+#include "fuse_lowlevel.h"
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+
+size_t fuse_buf_size(const struct fuse_bufvec *bufv)
+{
+	size_t i;
+	size_t size = 0;
+
+	for (i = 0; i < bufv->count; i++) {
+		if (bufv->buf[i].size == SIZE_MAX)
+			size = SIZE_MAX;
+		else
+			size += bufv->buf[i].size;
+	}
+
+	return size;
+}
+
+static size_t min_size(size_t s1, size_t s2)
+{
+	return s1 < s2 ? s1 : s2;
+}
+
+static ssize_t fuse_buf_write(const struct fuse_buf *dst, size_t dst_off,
+			      const struct fuse_buf *src, size_t src_off,
+			      size_t len)
+{
+	ssize_t res = 0;
+	size_t copied = 0;
+
+	while (len) {
+		if (dst->flags & FUSE_BUF_FD_SEEK) {
+			res = pwrite(dst->fd, src->mem + src_off, len,
+				     dst->pos + dst_off);
+		} else {
+			res = write(dst->fd, src->mem + src_off, len);
+		}
+		if (res == -1) {
+			if (!copied)
+				return -errno;
+			break;
+		}
+		if (res == 0)
+			break;
+
+		copied += res;
+		if (!(dst->flags & FUSE_BUF_FD_RETRY))
+			break;
+
+		src_off += res;
+		dst_off += res;
+		len -= res;
+	}
+
+	return copied;
+}
+
+static ssize_t fuse_buf_read(const struct fuse_buf *dst, size_t dst_off,
+			     const struct fuse_buf *src, size_t src_off,
+			     size_t len)
+{
+	ssize_t res = 0;
+	size_t copied = 0;
+
+	while (len) {
+		if (src->flags & FUSE_BUF_FD_SEEK) {
+			res = pread(src->fd, dst->mem + dst_off, len,
+				     src->pos + src_off);
+		} else {
+			res = read(src->fd, dst->mem + dst_off, len);
+		}
+		if (res == -1) {
+			if (!copied)
+				return -errno;
+			break;
+		}
+		if (res == 0)
+			break;
+
+		copied += res;
+		if (!(src->flags & FUSE_BUF_FD_RETRY))
+			break;
+
+		dst_off += res;
+		src_off += res;
+		len -= res;
+	}
+
+	return copied;
+}
+
+static ssize_t fuse_buf_fd_to_fd(const struct fuse_buf *dst, size_t dst_off,
+				 const struct fuse_buf *src, size_t src_off,
+				 size_t len)
+{
+	char buf[4096];
+	struct fuse_buf tmp = {
+		.size = sizeof(buf),
+		.flags = 0,
+	};
+	ssize_t res;
+	size_t copied = 0;
+
+	tmp.mem = buf;
+
+	while (len) {
+		size_t this_len = min_size(tmp.size, len);
+		size_t read_len;
+
+		res = fuse_buf_read(&tmp, 0, src, src_off, this_len);
+		if (res < 0) {
+			if (!copied)
+				return res;
+			break;
+		}
+		if (res == 0)
+			break;
+
+		read_len = res;
+		res = fuse_buf_write(dst, dst_off, &tmp, 0, read_len);
+		if (res < 0) {
+			if (!copied)
+				return res;
+			break;
+		}
+		if (res == 0)
+			break;
+
+		copied += res;
+
+		if (res < this_len)
+			break;
+
+		dst_off += res;
+		src_off += res;
+		len -= res;
+	}
+
+	return copied;
+}
+
+#ifdef HAVE_SPLICE
+static ssize_t fuse_buf_splice(const struct fuse_buf *dst, size_t dst_off,
+			       const struct fuse_buf *src, size_t src_off,
+			       size_t len, enum fuse_buf_copy_flags flags)
+{
+	int splice_flags = 0;
+	off64_t *srcpos = NULL;
+	off64_t *dstpos = NULL;
+	off64_t srcpos_val;
+	off64_t dstpos_val;
+	ssize_t res;
+	size_t copied = 0;
+
+	if (flags & FUSE_BUF_SPLICE_MOVE)
+		splice_flags |= SPLICE_F_MOVE;
+	if (flags & FUSE_BUF_SPLICE_NONBLOCK)
+		splice_flags |= SPLICE_F_NONBLOCK;
+
+	if (src->flags & FUSE_BUF_FD_SEEK) {
+		srcpos_val = src->pos + src_off;
+		srcpos = &srcpos_val;
+	}
+	if (dst->flags & FUSE_BUF_FD_SEEK) {
+		dstpos_val = dst->pos + dst_off;
+		dstpos = &dstpos_val;
+	}
+
+	while (len) {
+		res = splice(src->fd, srcpos, dst->fd, dstpos, len,
+			     splice_flags);
+		if (res == -1) {
+			if (copied)
+				break;
+
+			if (errno != EINVAL || (flags & FUSE_BUF_FORCE_SPLICE))
+				return -errno;
+
+			/* Maybe splice is not supported for this combination */
+			return fuse_buf_fd_to_fd(dst, dst_off, src, src_off,
+						 len);
+		}
+		if (res == 0)
+			break;
+
+		copied += res;
+		if (!(src->flags & FUSE_BUF_FD_RETRY) &&
+		    !(dst->flags & FUSE_BUF_FD_RETRY)) {
+			break;
+		}
+
+		len -= res;
+	}
+
+	return copied;
+}
+#else
+static ssize_t fuse_buf_splice(const struct fuse_buf *dst, size_t dst_off,
+			       const struct fuse_buf *src, size_t src_off,
+			       size_t len, enum fuse_buf_copy_flags flags)
+{
+	(void) flags;
+
+	return fuse_buf_fd_to_fd(dst, dst_off, src, src_off, len);
+}
+#endif
+
+
+static ssize_t fuse_buf_copy_one(const struct fuse_buf *dst, size_t dst_off,
+				 const struct fuse_buf *src, size_t src_off,
+				 size_t len, enum fuse_buf_copy_flags flags)
+{
+	int src_is_fd = src->flags & FUSE_BUF_IS_FD;
+	int dst_is_fd = dst->flags & FUSE_BUF_IS_FD;
+
+	if (!src_is_fd && !dst_is_fd) {
+		void *dstmem = dst->mem + dst_off;
+		void *srcmem = src->mem + src_off;
+
+		if (dstmem != srcmem) {
+			if (dstmem + len <= srcmem || srcmem + len <= dstmem)
+				memcpy(dstmem, srcmem, len);
+			else
+				memmove(dstmem, srcmem, len);
+		}
+
+		return len;
+	} else if (!src_is_fd) {
+		return fuse_buf_write(dst, dst_off, src, src_off, len);
+	} else if (!dst_is_fd) {
+		return fuse_buf_read(dst, dst_off, src, src_off, len);
+	} else if (flags & FUSE_BUF_NO_SPLICE) {
+		return fuse_buf_fd_to_fd(dst, dst_off, src, src_off, len);
+	} else {
+		return fuse_buf_splice(dst, dst_off, src, src_off, len, flags);
+	}
+}
+
+static const struct fuse_buf *fuse_bufvec_current(struct fuse_bufvec *bufv)
+{
+	if (bufv->idx < bufv->count)
+		return &bufv->buf[bufv->idx];
+	else
+		return NULL;
+}
+
+static int fuse_bufvec_advance(struct fuse_bufvec *bufv, size_t len)
+{
+	const struct fuse_buf *buf = fuse_bufvec_current(bufv);
+
+	bufv->off += len;
+	assert(bufv->off <= buf->size);
+	if (bufv->off == buf->size) {
+		assert(bufv->idx < bufv->count);
+		bufv->idx++;
+		if (bufv->idx == bufv->count)
+			return 0;
+		bufv->off = 0;
+	}
+	return 1;
+}
+
+ssize_t fuse_buf_copy(struct fuse_bufvec *dstv, struct fuse_bufvec *srcv,
+		      enum fuse_buf_copy_flags flags)
+{
+	size_t copied = 0;
+
+	if (dstv == srcv)
+		return fuse_buf_size(dstv);
+
+	for (;;) {
+		const struct fuse_buf *src = fuse_bufvec_current(srcv);
+		const struct fuse_buf *dst = fuse_bufvec_current(dstv);
+		size_t src_len;
+		size_t dst_len;
+		size_t len;
+		ssize_t res;
+
+		if (src == NULL || dst == NULL)
+			break;
+
+		src_len = src->size - srcv->off;
+		dst_len = dst->size - dstv->off;
+		len = min_size(src_len, dst_len);
+
+		res = fuse_buf_copy_one(dst, dstv->off, src, srcv->off, len, flags);
+		if (res < 0) {
+			if (!copied)
+				return res;
+			break;
+		}
+		copied += res;
+
+		if (!fuse_bufvec_advance(srcv, res) ||
+		    !fuse_bufvec_advance(dstv, res))
+			break;
+
+		if (res < len)
+			break;
+	}
+
+	return copied;
+}