yaffs: Improve xattrib to not modify if there is no space

[yaffs2.git] / yaffs_nameval.c

diff --git a/yaffs_nameval.c b/yaffs_nameval.c
index 88ee25bfd6c87d8c0ea4324abcdc529955bae7f8..b098600980b1ca24e46a8e94b9b1eac7bebc23ed 100644 (file)
--- a/yaffs_nameval.c
+++ b/yaffs_nameval.c
@@ -28,21 +28,27 @@
 
 #include "yportenv.h"
  
-static int nval_find(const char *xb, int xb_size, const char *name)
+static int nval_find(const char *xb, int xb_size, const char *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(strncmp(xb+pos+sizeof(int),name,size) == 0)
+               if(strncmp(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;
 }
 
@@ -64,7 +70,7 @@ static int nval_used(const char *xb, int xb_size)
 
 int nval_del(char *xb, int xb_size, const char *name)
 {
-       int pos  = nval_find(xb, xb_size, name);
+       int pos  = nval_find(xb, xb_size, name, NULL);
        int size;
        
        if(pos >= 0 && pos < xb_size){
@@ -79,37 +85,46 @@ int nval_del(char *xb, int xb_size, const char *name)
 
 int nval_set(char *xb, int xb_size, const char *name, const char *buf, int bsize, int flags)
 {
-       int pos = nval_find(xb,xb_size,name);
+       int pos;
        int namelen = 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 & NVAL_CREATE && pos >= 0)
                return -EEXIST;
        if(flags & NVAL_REPLACE && pos < 0)
                return -ENOENT;
 
-       nval_del(xb,xb_size,name);
+       start = nval_used(xb,xb_size);
+       space = xb_size - start + size_exist;
 
-       pos = nval_used(xb, xb_size);
-       
-       if(pos < xb_size && bsize < xb_size && namelen < xb_size){
-               reclen = (sizeof(int) + namelen + 1 + bsize);
-               if( pos + reclen < xb_size){
-                       memcpy(xb + pos,&reclen,sizeof(int));
-                       pos +=sizeof(int);
-                       strncpy(xb + pos, name, reclen);
-                       pos+= (namelen+1);
-                       memcpy(xb + pos,buf,bsize);
-                       pos+= bsize;
-                       return 0;
-               }
+       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);
        }
-       return -ENOSPC;
+
+       pos = start;
+
+       memcpy(xb + pos,&reclen,sizeof(int));
+       pos +=sizeof(int);
+       strncpy(xb + pos, name, reclen);
+       pos+= (namelen+1);
+       memcpy(xb + pos,buf,bsize);
+       return 0;
 }
 
 int nval_get(const char *xb, int xb_size, const char *name, char *buf, int bsize)
 {
-       int pos = nval_find(xb,xb_size,name);
+       int pos = nval_find(xb,xb_size,name,NULL);
        int size;
        
        if(pos >= 0 && pos< xb_size){