yaffsfs.c

这是ARM yaffs文件系统

int yaffs_unlink(const char *path) 
{
	return yaffsfs_DoUnlink(path,0);
}

int yaffs_rename(const char *oldPath, const char *newPath)
{
	yaffs_Object *olddir = NULL;
	yaffs_Object *newdir = NULL;
	yaffs_Object *obj = NULL;
	char *oldname;
	char *newname;
	int result= YAFFS_FAIL;
	int renameAllowed = 1;
	
	yaffsfs_Lock();
	
	olddir = yaffsfs_FindDirectory(NULL,oldPath,&oldname,0);
	newdir = yaffsfs_FindDirectory(NULL,newPath,&newname,0);
	obj = yaffsfs_FindObject(NULL,oldPath,0);
	
	if(!olddir || !newdir || !obj)
	{
		// bad file
		yaffsfs_SetError(-EBADF);	
		renameAllowed = 0;	
	}
	else if(olddir->myDev != newdir->myDev)
	{
		// oops must be on same device
		// todo error
		yaffsfs_SetError(-EXDEV);
		renameAllowed = 0;	
	}
	else if(obj && obj->variantType == YAFFS_OBJECT_TYPE_DIRECTORY)
	{
		// It is a directory, check that it is not being renamed to 
		// being its own decendent.
		// Do this by tracing from the new directory back to the root, checking for obj
		
		yaffs_Object *xx = newdir;
		
		while( renameAllowed && xx)
		{
			if(xx == obj)
			{
				renameAllowed = 0;
			}
			xx = xx->parent;
		}
		if(!renameAllowed) yaffsfs_SetError(-EACCESS);
	}
	
	if(renameAllowed)
	{
		result = yaffs_RenameObject(olddir,oldname,newdir,newname);
	}
	
	yaffsfs_Unlock();
	
	return (result == YAFFS_FAIL) ? -1 : 0;	
}


static int yaffsfs_DoStat(yaffs_Object *obj,struct yaffs_stat *buf)
{
	int retVal = -1;

	if(obj)
	{
		obj = yaffs_GetEquivalentObject(obj);
	}

	if(obj && buf)
	{
    	buf->st_dev = (int)obj->myDev->genericDevice;
    	buf->st_ino = obj->objectId;
    	buf->st_mode = obj->yst_mode & ~S_IFMT; // clear out file type bits
	
		if(obj->variantType == YAFFS_OBJECT_TYPE_DIRECTORY) 
		{
			buf->st_mode |= S_IFDIR;
		}
		else if(obj->variantType == YAFFS_OBJECT_TYPE_SYMLINK) 
		{
			buf->st_mode |= S_IFLNK;
		}
		else if(obj->variantType == YAFFS_OBJECT_TYPE_FILE)
		{
			buf->st_mode |= S_IFREG;
		}
		
    	buf->st_nlink = yaffs_GetObjectLinkCount(obj);
    	buf->st_uid = 0;    
    	buf->st_gid = 0;;     
    	buf->st_rdev = obj->yst_rdev;
    	buf->st_size = yaffs_GetObjectFileLength(obj);
		buf->st_blksize = obj->myDev->nDataBytesPerChunk;
    	buf->st_blocks = (buf->st_size + buf->st_blksize -1)/buf->st_blksize;
    	buf->yst_atime = obj->yst_atime; 
    	buf->yst_ctime = obj->yst_ctime; 
    	buf->yst_mtime = obj->yst_mtime; 
		retVal = 0;
	}
	return retVal;
}

static int yaffsfs_DoStatOrLStat(const char *path, struct yaffs_stat *buf,int doLStat)
{
	yaffs_Object *obj;
	
	int retVal = -1;
	
	yaffsfs_Lock();
	obj = yaffsfs_FindObject(NULL,path,0);
	
	if(!doLStat && obj)
	{
		obj = yaffsfs_FollowLink(obj,0);
	}
	
	if(obj)
	{
		retVal = yaffsfs_DoStat(obj,buf);
	}
	else
	{
		// todo error not found
		yaffsfs_SetError(-ENOENT);
	}
	
	yaffsfs_Unlock();
	
	return retVal;
	
}

int yaffs_stat(const char *path, struct yaffs_stat *buf)
{
	return yaffsfs_DoStatOrLStat(path,buf,0);
}

int yaffs_lstat(const char *path, struct yaffs_stat *buf)
{
	return yaffsfs_DoStatOrLStat(path,buf,1);
}

int yaffs_fstat(int fd, struct yaffs_stat *buf)
{
	yaffs_Object *obj;
	
	int retVal = -1;
	
	yaffsfs_Lock();
	obj = yaffsfs_GetHandleObject(fd);
	
	if(obj)
	{
		retVal = yaffsfs_DoStat(obj,buf);
	}
	else
	{
		// bad handle
		yaffsfs_SetError(-EBADF);		
	}
	
	yaffsfs_Unlock();
	
	return retVal;
}

static int yaffsfs_DoChMod(yaffs_Object *obj,mode_t mode)
{
	int result;

	if(obj)
	{
		obj = yaffs_GetEquivalentObject(obj);
	}
	
	if(obj)
	{
		obj->yst_mode = mode;
		obj->dirty = 1;
		result = yaffs_FlushFile(obj,0);
	}
	
	return result == YAFFS_OK ? 0 : -1;
}


int yaffs_chmod(const char *path, mode_t mode)
{
	yaffs_Object *obj;
	
	int retVal = -1;
	
	yaffsfs_Lock();
	obj = yaffsfs_FindObject(NULL,path,0);
	
	if(obj)
	{
		retVal = yaffsfs_DoChMod(obj,mode);
	}
	else
	{
		// todo error not found
		yaffsfs_SetError(-ENOENT);
	}
	
	yaffsfs_Unlock();
	
	return retVal;
	
}


int yaffs_fchmod(int fd, mode_t mode)
{
	yaffs_Object *obj;
	
	int retVal = -1;
	
	yaffsfs_Lock();
	obj = yaffsfs_GetHandleObject(fd);
	
	if(obj)
	{
		retVal = yaffsfs_DoChMod(obj,mode);
	}
	else
	{
		// bad handle
		yaffsfs_SetError(-EBADF);		
	}
	
	yaffsfs_Unlock();
	
	return retVal;
}


int yaffs_mkdir(const char *path, mode_t mode)
{
	yaffs_Object *parent = NULL;
	yaffs_Object *dir = NULL;
	char *name;
	int retVal= -1;
	
	yaffsfs_Lock();
	parent = yaffsfs_FindDirectory(NULL,path,&name,0);
	if(parent)
		dir = yaffs_MknodDirectory(parent,name,mode,0,0);
	if(dir)
	{
		retVal = 0;
	}
	else
	{
		yaffsfs_SetError(-ENOSPC); // just assume no space for now
		retVal = -1;
	}
	
	yaffsfs_Unlock();
	
	return retVal;
}

int yaffs_mount(const char *path)
{
	int retVal=-1;
	int result=YAFFS_FAIL;
	yaffs_Device *dev=NULL;
	char *dummy;
	
	T(YAFFS_TRACE_ALWAYS,("yaffs: Mounting %s\n",path));
	
	yaffsfs_Lock();
	dev = yaffsfs_FindDevice(path,&dummy);
	if(dev)
	{
		if(!dev->isMounted)
		{
			result = yaffs_GutsInitialise(dev);
			if(result == YAFFS_FAIL)
			{
				// todo error - mount failed
				yaffsfs_SetError(-ENOMEM);
			}
			retVal = result ? 0 : -1;
			
		}
		else
		{
			//todo error - already mounted.
			yaffsfs_SetError(-EBUSY);
		}
	}
	else
	{
		// todo error - no device
		yaffsfs_SetError(-ENODEV);
	}
	yaffsfs_Unlock();
	return retVal;
	
}

int yaffs_unmount(const char *path)
{
	int retVal=-1;
	yaffs_Device *dev=NULL;
	char *dummy;
	
	yaffsfs_Lock();
	dev = yaffsfs_FindDevice(path,&dummy);
	if(dev)
	{
		if(dev->isMounted)
		{
			int i;
			int inUse;
			
			yaffs_FlushEntireDeviceCache(dev);
			yaffs_CheckpointSave(dev);
			
			for(i = inUse = 0; i < YAFFSFS_N_HANDLES && !inUse; i++)
			{
				if(yaffsfs_handle[i].inUse && yaffsfs_handle[i].obj->myDev == dev)
				{
					inUse = 1; // the device is in use, can't unmount
				}
			}
			
			if(!inUse)
			{
				yaffs_Deinitialise(dev);
					
				retVal = 0;
			}
			else
			{
				// todo error can't unmount as files are open
				yaffsfs_SetError(-EBUSY);
			}
			
		}
		else
		{
			//todo error - not mounted.
			yaffsfs_SetError(-EINVAL);
			
		}
	}
	else
	{
		// todo error - no device
		yaffsfs_SetError(-ENODEV);
	}	
	yaffsfs_Unlock();
	return retVal;
	
}

loff_t yaffs_freespace(const char *path)
{
	loff_t retVal=-1;
	yaffs_Device *dev=NULL;
	char *dummy;
	
	yaffsfs_Lock();
	dev = yaffsfs_FindDevice(path,&dummy);
	if(dev  && dev->isMounted)
	{
		retVal = yaffs_GetNumberOfFreeChunks(dev);
		retVal *= dev->nDataBytesPerChunk;
		
	}
	else
	{
		yaffsfs_SetError(-EINVAL);
	}
	
	yaffsfs_Unlock();
	return retVal;	
}



void yaffs_initialise(yaffsfs_DeviceConfiguration *cfgList)
{
	
	yaffsfs_DeviceConfiguration *cfg;
	
	yaffsfs_configurationList = cfgList;
	
	yaffsfs_InitHandles();
	
	cfg = yaffsfs_configurationList;
	
	while(cfg && cfg->prefix && cfg->dev)
	{
		cfg->dev->isMounted = 0;
		cfg->dev->removeObjectCallback = yaffsfs_RemoveObjectCallback;
		cfg++;
	}
	
	
}


//
// Directory search stuff.

//
// Directory search context
//
// NB this is an opaque structure.


typedef struct
{
	__u32 magic;
	yaffs_dirent de;		/* directory entry being used by this dsc */
	char name[NAME_MAX+1];		/* name of directory being searched */
	yaffs_Object *dirObj;		/* ptr to directory being searched */
	yaffs_Object *nextReturn;	/* obj to be returned by next readddir */
	int offset;
	struct list_head others;	
} yaffsfs_DirectorySearchContext;



static struct list_head search_contexts;


static void yaffsfs_SetDirRewound(yaffsfs_DirectorySearchContext *dsc)
{
	if(dsc &&
	   dsc->dirObj &&
	   dsc->dirObj->variantType == YAFFS_OBJECT_TYPE_DIRECTORY){
	   
	   dsc->offset = 0;
	   
	   if( list_empty(&dsc->dirObj->variant.directoryVariant.children)){
	   	dsc->nextReturn = NULL;
	   } else {
	      	dsc->nextReturn = list_entry(dsc->dirObj->variant.directoryVariant.children.next,
						yaffs_Object,siblings);
	   }
	} else {
		/* Hey someone isn't playing nice! */
	}
}

static void yaffsfs_DirAdvance(yaffsfs_DirectorySearchContext *dsc)
{
	if(dsc &&
	   dsc->dirObj &&
	   dsc->dirObj->variantType == YAFFS_OBJECT_TYPE_DIRECTORY){
	   
	   if( dsc->nextReturn == NULL ||
	       list_empty(&dsc->dirObj->variant.directoryVariant.children)){
	   	dsc->nextReturn = NULL;
	   } else {
		   struct list_head *next = dsc->nextReturn->siblings.next;
   
		   if( next == &dsc->dirObj->variant.directoryVariant.children)
	   		dsc->nextReturn = NULL; /* end of list */
	   	   else 
		   	dsc->nextReturn = list_entry(next,yaffs_Object,siblings);
	   }
	} else {
		/* Hey someone isn't playing nice! */
	}
}

static void yaffsfs_RemoveObjectCallback(yaffs_Object *obj)
{

	struct list_head *i;
	yaffsfs_DirectorySearchContext *dsc;
	
	/* if search contexts not initilised then skip */
	if(!search_contexts.next)
		return;
		
	/* Iteratethrough the directory search contexts.
	 * If any are the one being removed, then advance the dsc to
	 * the next one to prevent a hanging ptr.
	 */
	 list_for_each(i, &search_contexts) {
		if (i) {
			dsc = list_entry(i, yaffsfs_DirectorySearchContext,others);
			if(dsc->nextReturn == obj)
				yaffsfs_DirAdvance(dsc);
		}
	}
				
}

yaffs_DIR *yaffs_opendir(const char *dirname)
{
	yaffs_DIR *dir = NULL;
 	yaffs_Object *obj = NULL;
	yaffsfs_DirectorySearchContext *dsc = NULL;
	
	yaffsfs_Lock();
	
	obj = yaffsfs_FindObject(NULL,dirname,0);
	
	if(obj && obj->variantType == YAFFS_OBJECT_TYPE_DIRECTORY)
	{
		
		dsc = YMALLOC(sizeof(yaffsfs_DirectorySearchContext));
		dir = (yaffs_DIR *)dsc;
		if(dsc)
		{
			memset(dsc,0,sizeof(yaffsfs_DirectorySearchContext));
			dsc->magic = YAFFS_MAGIC;
			dsc->dirObj = obj;
			strncpy(dsc->name,dirname,NAME_MAX);
			INIT_LIST_HEAD(&dsc->others);
			
			if(!search_contexts.next)
				INIT_LIST_HEAD(&search_contexts);
				
			list_add(&dsc->others,&search_contexts);	
			yaffsfs_SetDirRewound(dsc);		}
	
	}
	
	yaffsfs_Unlock();
	
	return dir;
}

struct yaffs_dirent *yaffs_readdir(yaffs_DIR *dirp)
{
	yaffsfs_DirectorySearchContext *dsc = (yaffsfs_DirectorySearchContext *)dirp;
	struct yaffs_dirent *retVal = NULL;
		
	yaffsfs_Lock();
	
	if(dsc && dsc->magic == YAFFS_MAGIC){
		yaffsfs_SetError(0);
		if(dsc->nextReturn){
			dsc->de.d_ino = yaffs_GetEquivalentObject(dsc->nextReturn)->objectId;
			dsc->de.d_dont_use = (unsigned)dsc->nextReturn;
			dsc->de.d_off = dsc->offset++;
			yaffs_GetObjectName(dsc->nextReturn,dsc->de.d_name,NAME_MAX);
			if(strlen(dsc->de.d_name) == 0)
			{
				// this should not happen!
				strcpy(dsc->de.d_name,"zz");
			}
			dsc->de.d_reclen = sizeof(struct yaffs_dirent);
			retVal = &dsc->de;
			yaffsfs_DirAdvance(dsc);
		} else
			retVal = NULL;
	}
	else
	{
		yaffsfs_SetError(-EBADF);
	}
	
	yaffsfs_Unlock();
	
	return retVal;
	
}


void yaffs_rewinddir(yaffs_DIR *dirp)
{
	yaffsfs_DirectorySearchContext *dsc = (yaffsfs_DirectorySearchContext *)dirp;
	
	yaffsfs_Lock();
	
	yaffsfs_SetDirRewound(dsc);

	yaffsfs_Unlock();
}


int yaffs_closedir(yaffs_DIR *dirp)
{
	yaffsfs_DirectorySearchContext *dsc = (yaffsfs_DirectorySearchContext *)dirp;
		
	yaffsfs_Lock();
	dsc->magic = 0;
	list_del(&dsc->others); /* unhook from list */
	YFREE(dsc);
	yaffsfs_Unlock();
	return 0;
}

// end of directory stuff


int yaffs_symlink(const char *oldpath, const char *newpath)
{
	yaffs_Object *parent = NULL;
	yaffs_Object *obj;
	char *name;
	int retVal= -1;
	int mode = 0; // ignore for now
	
	yaffsfs_Lock();
	parent = yaffsfs_FindDirectory(NULL,newpath,&name,0);
	obj = yaffs_MknodSymLink(parent,name,mode,0,0,oldpath);
	if(obj)
	{
		retVal = 0;
	}
	else
	{
		yaffsfs_SetError(-ENOSPC); // just assume no space for now
		retVal = -1;
	}
	
	yaffsfs_Unlock();
	
	return retVal;
	
}

int yaffs_readlink(const char *path, char *buf, int bufsiz)
{
	yaffs_Object *obj = NULL;
	int retVal;

		
	yaffsfs_Lock();
	
	obj = yaffsfs_FindObject(NULL,path,0);
	
	if(!obj)
	{
		yaffsfs_SetError(-ENOENT);
		retVal = -1;
	}
	else if(obj->variantType != YAFFS_OBJECT_TYPE_SYMLINK)
	{
		yaffsfs_SetError(-EINVAL);
		retVal = -1;
	}
	else
	{
		char *alias = obj->variant.symLinkVariant.alias;
		memset(buf,0,bufsiz);
		strncpy(buf,alias,bufsiz - 1);
		retVal = 0;
	}
	yaffsfs_Unlock();
	return retVal;
}

int yaffs_link(const char *oldpath, const char *newpath)
{
	// Creates a link called newpath to existing oldpath
	yaffs_Object *obj = NULL;
	yaffs_Object *target = NULL;
	int retVal = 0;

		
	yaffsfs_Lock();
	
	obj = yaffsfs_FindObject(NULL,oldpath,0);
	target = yaffsfs_FindObject(NULL,newpath,0);
	
	if(!obj)
	{
		yaffsfs_SetError(-ENOENT);
		retVal = -1;
	}
	else if(target)
	{
		yaffsfs_SetError(-EEXIST);
		retVal = -1;
	}
	else	
	{
		yaffs_Object *newdir = NULL;
		yaffs_Object *link = NULL;
		
		char *newname;
		
		newdir = yaffsfs_FindDirectory(NULL,newpath,&newname,0);
		
		if(!newdir)
		{
			yaffsfs_SetError(-ENOTDIR);
			retVal = -1;
		}
		else if(newdir->myDev != obj->myDev)
		{
			yaffsfs_SetError(-EXDEV);
			retVal = -1;
		}
		if(newdir && strlen(newname) > 0)
		{
			link = yaffs_Link(newdir,newname,obj);
			if(link)
				retVal = 0;
			else
			{
				yaffsfs_SetError(-ENOSPC);
				retVal = -1;
			}

		}
	}
	yaffsfs_Unlock();
	
	return retVal;
}

int yaffs_mknod(const char *pathname, mode_t mode, dev_t dev);

int yaffs_DumpDevStruct(const char *path)
{
	char *rest;
	
	yaffs_Object *obj = yaffsfs_FindRoot(path,&rest);
	
	if(obj)
	{
		yaffs_Device *dev = obj->myDev;
		
		printf("\n"
			   "nPageWrites.......... %d\n"
			   "nPageReads........... %d\n"
			   "nBlockErasures....... %d\n"
			   "nGCCopies............ %d\n"
			   "garbageCollections... %d\n"
			   "passiveGarbageColl'ns %d\n"
			   "\n",
				dev->nPageWrites,
				dev->nPageReads,
				dev->nBlockErasures,
				dev->nGCCopies,
				dev->garbageCollections,
				dev->passiveGarbageCollections
		);
		
	}
	return 0;
}