yaffs Add sharing control to yaffs direct

[yaffs2.git] / direct / yaffsfs.c

diff --git a/direct/yaffsfs.c b/direct/yaffsfs.c
index b709d93fed1edf91332a66f756b3db6bae7ef813..d87bc8073f476fb5e7fe38c3dc276cb6fa79d59e 100644 (file)
--- a/direct/yaffsfs.c
+++ b/direct/yaffsfs.c
@@ -53,10 +53,13 @@ typedef struct {
 } yaffsfs_Inode;
 
 typedef struct{
-       __u8    readOnly:1;
+       __u8    reading:1;
+       __u8    writing:1;
        __u8    append:1;
-       int     inodeId:13;     /* Index to corresponding yaffsfs_Inode */
-       int     useCount:16;    /* Use count for this handle */
+       __u8    shareRead:1;
+       __u8    shareWrite:1;
+       int     inodeId:12;     /* Index to corresponding yaffsfs_Inode */
+       int     useCount:10;    /* Use count for this handle */
        __u32 position;         /* current position in file */
 }yaffsfs_Handle;
 
@@ -561,7 +564,7 @@ int yaffs_dup(int fd)
 
 }
 
-int yaffs_open(const YCHAR *path, int oflag, int mode)
+int yaffs_open_sharing(const YCHAR *path, int oflag, int mode, int sharing)
 {
        yaffs_Object *obj = NULL;
        yaffs_Object *dir = NULL;
@@ -571,6 +574,14 @@ int yaffs_open(const YCHAR *path, int oflag, int mode)
        int openDenied = 0;
        int symDepth = 0;
        int errorReported = 0;
+       __u8 shareRead = (sharing & YAFFS_SHARE_READ) ?  1 : 0;
+       __u8 shareWrite = (sharing & YAFFS_SHARE_WRITE) ? 1 : 0;
+       __u8 sharedReadAllowed;
+       __u8 sharedWriteAllowed;
+       __u8 alreadyReading;
+       __u8 alreadyWriting;
+       __u8 readRequested;
+       __u8 writeRequested;
 
        /* O_EXCL only has meaning if O_CREAT is specified */
        if(!(oflag & O_CREAT))
@@ -591,7 +602,6 @@ int yaffs_open(const YCHAR *path, int oflag, int mode)
 
                h = yaffsfs_GetHandlePointer(handle);
 
-
                /* try to find the exisiting object */
                obj = yaffsfs_FindObject(NULL,path,0);
 
@@ -639,6 +649,43 @@ int yaffs_open(const YCHAR *path, int oflag, int mode)
                           !(obj->yst_mode & S_IWRITE))
                                openDenied = 1;
 
+                       /* Check sharing of an existing object. */
+                       {
+                               yaffsfs_Handle *h;
+                               int i;
+                               sharedReadAllowed = 1;
+                               sharedWriteAllowed = 1;
+                               alreadyReading = 0;
+                               alreadyWriting = 0;
+                               for( i = 0; i < YAFFSFS_N_HANDLES; i++){
+                                       h = &yaffsfs_handle[i];
+                                       if(h->useCount > 0 &&
+                                               h->inodeId >= 0 &&
+                                               yaffsfs_inode[h->inodeId].iObj == obj){
+                                               if(!h->shareRead)
+                                                       sharedReadAllowed = 0;
+                                               if(!h->shareWrite)
+                                                       sharedWriteAllowed = 0;
+                                               if(h->reading)
+                                                       alreadyReading = 1;
+                                               if(h->writing)
+                                                       alreadyWriting = 0;
+                                       }
+                               }
+
+                               readRequested = (oflag & (O_RDWR | O_RDONLY)) ? 1 : 0;
+                               writeRequested = (oflag & (O_RDWR | O_WRONLY)) ? 1 : 0;
+
+                               if((!sharedReadAllowed && readRequested)|| 
+                                       (!shareRead  && alreadyReading) ||
+                                       (!sharedWriteAllowed && writeRequested) ||
+                                       (!shareWrite && alreadyWriting)){
+                                       openDenied = 1;
+                                       yaffsfs_SetError(-EBUSY);
+                                       errorReported=1;
+                               }
+                       }
+
                } else if((oflag & O_CREAT)) {
                        /* Let's see if we can create this file */
                        dir = yaffsfs_FindDirectory(NULL,path,&name,0);
@@ -664,14 +711,17 @@ int yaffs_open(const YCHAR *path, int oflag, int mode)
                        }
                        
                        h->inodeId = inodeId;
-                       h->readOnly = (oflag & (O_WRONLY | O_RDWR)) ? 0 : 1;
+                       h->reading = (oflag & (O_RDONLY | O_RDWR)) ? 1 : 0;
+                       h->writing = (oflag & (O_WRONLY | O_RDWR)) ? 1 : 0;
                        h->append =  (oflag & O_APPEND) ? 1 : 0;
                        h->position = 0;
+                       h->shareRead = shareRead;
+                       h->shareWrite = shareWrite;
 
                        /* Hook inode to object */
                         obj->myInode = (void*) &yaffsfs_inode[inodeId];
 
-                        if((oflag & O_TRUNC) && !h->readOnly)
+                        if((oflag & O_TRUNC) && h->writing)
                                 yaffs_ResizeFile(obj,0);
                } else {
                        yaffsfs_PutHandle(handle);
@@ -688,6 +738,11 @@ int yaffs_open(const YCHAR *path, int oflag, int mode)
        return handle;
 }
 
+int yaffs_open(const YCHAR *path, int oflag, int mode)
+{
+       return yaffs_open_sharing(path, oflag, mode, YAFFS_SHARE_READ | YAFFS_SHARE_WRITE);
+}
+
 int yaffs_Dofsync(int fd,int datasync)
 {
        yaffsfs_Handle *h = NULL;
@@ -865,7 +920,7 @@ int yaffsfs_do_write(int fd, const void *vbuf, unsigned int nbyte, int isPwrite,
                /* bad handle */
                yaffsfs_SetError(-EBADF);
                totalWritten = -1;
-       } else if( h && obj && (h->readOnly || obj->myDev->readOnly)){
+       } else if( h && obj && (!h->writing || obj->myDev->readOnly)){
                yaffsfs_SetError(-EINVAL);
                totalWritten=-1;
        } else if( h && obj){