From: Stefan Hajnoczi <stefa...@redhat.com>
Introduce an API for consuming bytes from a buffer with size checks.
All FUSE operations will be converted to use this safe API instead of
void *inarg.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
contrib/virtiofsd/buffer.c | 28 +++++++++++++++++++
contrib/virtiofsd/fuse_common.h | 48 +++++++++++++++++++++++++++++++++
2 files changed, 76 insertions(+)
diff --git a/contrib/virtiofsd/buffer.c b/contrib/virtiofsd/buffer.c
index 3c9b443fa0..2a0d123bde 100644
--- a/contrib/virtiofsd/buffer.c
+++ b/contrib/virtiofsd/buffer.c
@@ -316,3 +316,31 @@ ssize_t fuse_buf_copy(struct fuse_bufvec *dstv, struct
fuse_bufvec *srcv,
return copied;
}
+
+void *fuse_mbuf_iter_advance(struct fuse_mbuf_iter *iter, size_t len)
+{
+ void *ptr;
+
+ if (len > iter->size - iter->pos) {
+ return NULL;
+ }
+
+ ptr = iter->mem + iter->pos;
+ iter->pos += len;
+ return ptr;
+}
+
+const char *fuse_mbuf_iter_advance_str(struct fuse_mbuf_iter *iter)
+{
+ const char *str = iter->mem + iter->pos;
+ size_t remaining = iter->size - iter->pos;
+ size_t i;
+
+ for (i = 0; i < remaining; i++) {
+ if (str[i] == '\0') {
+ iter->pos += i + 1;
+ return str;
+ }
+ }
+ return NULL;
+}
diff --git a/contrib/virtiofsd/fuse_common.h b/contrib/virtiofsd/fuse_common.h
index 2d686b2ac4..b5b6d270fe 100644
--- a/contrib/virtiofsd/fuse_common.h
+++ b/contrib/virtiofsd/fuse_common.h
@@ -760,6 +760,54 @@ size_t fuse_buf_size(const struct fuse_bufvec *bufv);
ssize_t fuse_buf_copy(struct fuse_bufvec *dst, struct fuse_bufvec *src,
enum fuse_buf_copy_flags flags);
+/**
+ * Memory buffer iterator
+ *
+ */
+struct fuse_mbuf_iter {
+ /**
+ * Data pointer
+ */
+ void *mem;
+
+ /**
+ * Total length, in bytes
+ */
+ size_t size;
+
+ /**
+ * Offset from start of buffer
+ */
+ size_t pos;
+};
+
+/* Initialize memory buffer iterator from a fuse_buf */
+#define FUSE_MBUF_ITER_INIT(fbuf) \
+ ((struct fuse_mbuf_iter) { \
+ .mem = fbuf->mem, \
+ .size = fbuf->size, \
+ .pos = 0, \
+ })
+
+/**
+ * Consume bytes from a memory buffer iterator
+ *
+ * @param iter memory buffer iterator
+ * @param len number of bytes to consume
+ * @return pointer to start of consumed bytes or
+ * NULL if advancing beyond end of buffer
+ */
+void *fuse_mbuf_iter_advance(struct fuse_mbuf_iter *iter, size_t len);
+
+/**
+ * Consume a NUL-terminated string from a memory buffer iterator
+ *
+ * @param iter memory buffer iterator
+ * @return pointer to the string or
+ * NULL if advancing beyond end of buffer or there is no NUL-terminator
+ */
+const char *fuse_mbuf_iter_advance_str(struct fuse_mbuf_iter *iter);
+
/* ----------------------------------------------------------- *
* Signal handling *
* ----------------------------------------------------------- */
--
2.23.0
