generic: fold yaffs_git_2010_10_20 patch to generic/files

[15.05/openwrt.git] / target / linux / generic / files / fs / yaffs2 / yaffs_nameval.c

diff --git a/target/linux/generic/files/fs/yaffs2/yaffs_nameval.c b/target/linux/generic/files/fs/yaffs2/yaffs_nameval.c
new file mode 100644 (file)
index 0000000..a4ed297
--- /dev/null
+++ b/target/linux/generic/files/fs/yaffs2/yaffs_nameval.c
@@ -0,0 +1,197 @@
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2010 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.
+ *  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) == 0){
+                       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 -1;
+}
+
+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){
+               /* 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;
+       } else
+               return -ENODATA;
+}
+
+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(size <= bsize){
+                       memcpy(buf,xb + pos,size);
+                       return size;
+               }
+               
+       }
+       if(pos >= 0)
+               return -ERANGE;
+       else
+               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;
+}