2 FUSE: Filesystem in Userspace
3 Copyright (C) 2010 Miklos Szeredi <miklos@szeredi.hu>
5 This program can be distributed under the terms of the GNU LGPLv2.
6 See the file COPYING.LIB
13 #include "fuse_lowlevel.h"
19 size_t fuse_buf_size(const struct fuse_bufvec *bufv)
24 for (i = 0; i < bufv->count; i++) {
25 if (bufv->buf[i].size == SIZE_MAX)
28 size += bufv->buf[i].size;
34 static size_t min_size(size_t s1, size_t s2)
36 return s1 < s2 ? s1 : s2;
39 static ssize_t fuse_buf_write(const struct fuse_buf *dst, size_t dst_off,
40 const struct fuse_buf *src, size_t src_off,
47 if (dst->flags & FUSE_BUF_FD_SEEK) {
48 res = pwrite(dst->fd, src->mem + src_off, len,
51 res = write(dst->fd, src->mem + src_off, len);
62 if (!(dst->flags & FUSE_BUF_FD_RETRY))
73 static ssize_t fuse_buf_read(const struct fuse_buf *dst, size_t dst_off,
74 const struct fuse_buf *src, size_t src_off,
81 if (src->flags & FUSE_BUF_FD_SEEK) {
82 res = pread(src->fd, dst->mem + dst_off, len,
85 res = read(src->fd, dst->mem + dst_off, len);
96 if (!(src->flags & FUSE_BUF_FD_RETRY))
107 static ssize_t fuse_buf_fd_to_fd(const struct fuse_buf *dst, size_t dst_off,
108 const struct fuse_buf *src, size_t src_off,
112 struct fuse_buf tmp = {
122 size_t this_len = min_size(tmp.size, len);
125 res = fuse_buf_read(&tmp, 0, src, src_off, this_len);
135 res = fuse_buf_write(dst, dst_off, &tmp, 0, read_len);
158 static ssize_t fuse_buf_splice(const struct fuse_buf *dst, size_t dst_off,
159 const struct fuse_buf *src, size_t src_off,
160 size_t len, enum fuse_buf_copy_flags flags)
162 int splice_flags = 0;
163 off_t *srcpos = NULL;
164 off_t *dstpos = NULL;
170 if (flags & FUSE_BUF_SPLICE_MOVE)
171 splice_flags |= SPLICE_F_MOVE;
172 if (flags & FUSE_BUF_SPLICE_NONBLOCK)
173 splice_flags |= SPLICE_F_NONBLOCK;
175 if (src->flags & FUSE_BUF_FD_SEEK) {
176 srcpos_val = src->pos + src_off;
177 srcpos = &srcpos_val;
179 if (dst->flags & FUSE_BUF_FD_SEEK) {
180 dstpos_val = dst->pos + dst_off;
181 dstpos = &dstpos_val;
185 res = splice(src->fd, srcpos, dst->fd, dstpos, len,
191 if (errno != EINVAL || (flags & FUSE_BUF_FORCE_SPLICE))
194 /* Maybe splice is not supported for this combination */
195 return fuse_buf_fd_to_fd(dst, dst_off, src, src_off,
202 if (!(src->flags & FUSE_BUF_FD_RETRY) &&
203 !(dst->flags & FUSE_BUF_FD_RETRY)) {
213 static ssize_t fuse_buf_splice(const struct fuse_buf *dst, size_t dst_off,
214 const struct fuse_buf *src, size_t src_off,
215 size_t len, enum fuse_buf_copy_flags flags)
219 return fuse_buf_fd_to_fd(dst, dst_off, src, src_off, len);
224 static ssize_t fuse_buf_copy_one(const struct fuse_buf *dst, size_t dst_off,
225 const struct fuse_buf *src, size_t src_off,
226 size_t len, enum fuse_buf_copy_flags flags)
228 int src_is_fd = src->flags & FUSE_BUF_IS_FD;
229 int dst_is_fd = dst->flags & FUSE_BUF_IS_FD;
231 if (!src_is_fd && !dst_is_fd) {
232 void *dstmem = dst->mem + dst_off;
233 void *srcmem = src->mem + src_off;
235 if (dstmem != srcmem) {
236 if (dstmem + len <= srcmem || srcmem + len <= dstmem)
237 memcpy(dstmem, srcmem, len);
239 memmove(dstmem, srcmem, len);
243 } else if (!src_is_fd) {
244 return fuse_buf_write(dst, dst_off, src, src_off, len);
245 } else if (!dst_is_fd) {
246 return fuse_buf_read(dst, dst_off, src, src_off, len);
247 } else if (flags & FUSE_BUF_NO_SPLICE) {
248 return fuse_buf_fd_to_fd(dst, dst_off, src, src_off, len);
250 return fuse_buf_splice(dst, dst_off, src, src_off, len, flags);
254 static const struct fuse_buf *fuse_bufvec_current(struct fuse_bufvec *bufv)
256 if (bufv->idx < bufv->count)
257 return &bufv->buf[bufv->idx];
262 static int fuse_bufvec_advance(struct fuse_bufvec *bufv, size_t len)
264 const struct fuse_buf *buf = fuse_bufvec_current(bufv);
267 assert(bufv->off <= buf->size);
268 if (bufv->off == buf->size) {
269 assert(bufv->idx < bufv->count);
271 if (bufv->idx == bufv->count)
278 ssize_t fuse_buf_copy(struct fuse_bufvec *dstv, struct fuse_bufvec *srcv,
279 enum fuse_buf_copy_flags flags)
284 return fuse_buf_size(dstv);
287 const struct fuse_buf *src = fuse_bufvec_current(srcv);
288 const struct fuse_buf *dst = fuse_bufvec_current(dstv);
294 if (src == NULL || dst == NULL)
297 src_len = src->size - srcv->off;
298 dst_len = dst->size - dstv->off;
299 len = min_size(src_len, dst_len);
301 res = fuse_buf_copy_one(dst, dstv->off, src, srcv->off, len, flags);
309 if (!fuse_bufvec_advance(srcv, res) ||
310 !fuse_bufvec_advance(dstv, res))