--- /dev/null
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2011 Aleph One Ltd.
+ * for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * This simple implementation of a name-value store assumes a small number of
+* values and fits into a small finite buffer.
+ *
+ * Each attribute is stored as a record:
+ * sizeof(int) bytes record size.
+ * yaffs_strnlen+1 bytes name null terminated.
+ * nbytes value.
+ * ----------
+ * total size stored in record size
+ *
+ * This code has not been tested with unicode yet.
+ */
+
+#include "yaffs_nameval.h"
+
+#include "yportenv.h"
+
+static int nval_find(const char *xb, int xb_size, const YCHAR *name,
+ int *exist_size)
+{
+ int pos = 0;
+ int size;
+
+ memcpy(&size, xb, sizeof(int));
+ while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
+ if (!yaffs_strncmp((YCHAR *) (xb + pos + sizeof(int)),
+ name, size)) {
+ if (exist_size)
+ *exist_size = size;
+ return pos;
+ }
+ pos += size;
+ if (pos < xb_size - sizeof(int))
+ memcpy(&size, xb + pos, sizeof(int));
+ else
+ size = 0;
+ }
+ if (exist_size)
+ *exist_size = 0;
+ return -ENODATA;
+}
+
+static int nval_used(const char *xb, int xb_size)
+{
+ int pos = 0;
+ int size;
+
+ memcpy(&size, xb + pos, sizeof(int));
+ while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
+ pos += size;
+ if (pos < xb_size - sizeof(int))
+ memcpy(&size, xb + pos, sizeof(int));
+ else
+ size = 0;
+ }
+ return pos;
+}
+
+int nval_del(char *xb, int xb_size, const YCHAR *name)
+{
+ int pos = nval_find(xb, xb_size, name, NULL);
+ int size;
+
+ if (pos < 0 || pos >= xb_size)
+ return -ENODATA;
+
+ /* Find size, shift rest over this record,
+ * then zero out the rest of buffer */
+ memcpy(&size, xb + pos, sizeof(int));
+ memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
+ memset(xb + (xb_size - size), 0, size);
+ return 0;
+}
+
+int nval_set(char *xb, int xb_size, const YCHAR *name, const char *buf,
+ int bsize, int flags)
+{
+ int pos;
+ int namelen = yaffs_strnlen(name, xb_size);
+ int reclen;
+ int size_exist = 0;
+ int space;
+ int start;
+
+ pos = nval_find(xb, xb_size, name, &size_exist);
+
+ if (flags & XATTR_CREATE && pos >= 0)
+ return -EEXIST;
+ if (flags & XATTR_REPLACE && pos < 0)
+ return -ENODATA;
+
+ start = nval_used(xb, xb_size);
+ space = xb_size - start + size_exist;
+
+ reclen = (sizeof(int) + namelen + 1 + bsize);
+
+ if (reclen > space)
+ return -ENOSPC;
+
+ if (pos >= 0) {
+ nval_del(xb, xb_size, name);
+ start = nval_used(xb, xb_size);
+ }
+
+ pos = start;
+
+ memcpy(xb + pos, &reclen, sizeof(int));
+ pos += sizeof(int);
+ yaffs_strncpy((YCHAR *) (xb + pos), name, reclen);
+ pos += (namelen + 1);
+ memcpy(xb + pos, buf, bsize);
+ return 0;
+}
+
+int nval_get(const char *xb, int xb_size, const YCHAR * name, char *buf,
+ int bsize)
+{
+ int pos = nval_find(xb, xb_size, name, NULL);
+ int size;
+
+ if (pos >= 0 && pos < xb_size) {
+
+ memcpy(&size, xb + pos, sizeof(int));
+ pos += sizeof(int); /* advance past record length */
+ size -= sizeof(int);
+
+ /* Advance over name string */
+ while (xb[pos] && size > 0 && pos < xb_size) {
+ pos++;
+ size--;
+ }
+ /*Advance over NUL */
+ pos++;
+ size--;
+
+ /* If bsize is zero then this is a size query.
+ * Return the size, but don't copy.
+ */
+ if (!bsize)
+ return size;
+
+ if (size <= bsize) {
+ memcpy(buf, xb + pos, size);
+ return size;
+ }
+ }
+ if (pos >= 0)
+ return -ERANGE;
+
+ return -ENODATA;
+}
+
+int nval_list(const char *xb, int xb_size, char *buf, int bsize)
+{
+ int pos = 0;
+ int size;
+ int name_len;
+ int ncopied = 0;
+ int filled = 0;
+
+ memcpy(&size, xb + pos, sizeof(int));
+ while (size > sizeof(int) &&
+ size <= xb_size &&
+ (pos + size) < xb_size &&
+ !filled) {
+ pos += sizeof(int);
+ size -= sizeof(int);
+ name_len = yaffs_strnlen((YCHAR *) (xb + pos), size);
+ if (ncopied + name_len + 1 < bsize) {
+ memcpy(buf, xb + pos, name_len * sizeof(YCHAR));
+ buf += name_len;
+ *buf = '\0';
+ buf++;
+ if (sizeof(YCHAR) > 1) {
+ *buf = '\0';
+ buf++;
+ }
+ ncopied += (name_len + 1);
+ } else {
+ filled = 1;
+ }
+ pos += size;
+ if (pos < xb_size - sizeof(int))
+ memcpy(&size, xb + pos, sizeof(int));
+ else
+ size = 0;
+ }
+ return ncopied;
+}
+
+int nval_hasvalues(const char *xb, int xb_size)
+{
+ return nval_used(xb, xb_size) > 0;
+}
Code Review / kvmfornfv.git / blobdiff