--- MiNT/src/unifs.c	2018/04/24 17:55:36	1.1
+++ MiNT/src/unifs.c	2018/04/24 17:58:54	1.1.1.6
@@ -1,6 +1,10 @@
 /*
 
-Copyright 1991,1992 Eric R. Smith. All rights reserved.
+Copyright 1991,1992 Eric R. Smith.
+
+Copyright 1992,1993,1994 Atari Corporation.
+
+All rights reserved.
 
  */
 
@@ -20,45 +24,49 @@ extern FILESYS bios_filesys, proc_filesy
 
 
 
-static long	uni_root	P_((int drv, fcookie *fc));
+static long	ARGS_ON_STACK uni_root	P_((int drv, fcookie *fc));
+
+static long	ARGS_ON_STACK uni_lookup	P_((fcookie *dir, const char *name, fcookie *fc));
 
-static long	uni_lookup	P_((fcookie *dir, const char *name, fcookie *fc));
+static long	ARGS_ON_STACK uni_getxattr	P_((fcookie *fc, XATTR *xattr));
 
-static long	uni_getxattr	P_((fcookie *fc, XATTR *xattr));
+static long	ARGS_ON_STACK uni_chattr	P_((fcookie *fc, int attrib));
 
-static long	uni_chattr	P_((fcookie *fc, int attrib));
+static long	ARGS_ON_STACK uni_chown	P_((fcookie *fc, int uid, int gid));
 
-static long	uni_chown	P_((fcookie *fc, int uid, int gid));
+static long	ARGS_ON_STACK uni_chmode	P_((fcookie *fc, unsigned mode));
 
-static long	uni_chmode	P_((fcookie *fc, unsigned mode));
+static long	ARGS_ON_STACK uni_rmdir	P_((fcookie *dir, const char *name));
 
-static long	uni_rmdir	P_((fcookie *dir, const char *name));
+static long	ARGS_ON_STACK uni_remove	P_((fcookie *dir, const char *name));
 
-static long	uni_remove	P_((fcookie *dir, const char *name));
+static long	ARGS_ON_STACK uni_getname	P_((fcookie *root, fcookie *dir,
 
-static long	uni_getname	P_((fcookie *root, fcookie *dir, char *pathname));
+						    char *pathname, int size));
 
-static long	uni_rename	P_((fcookie *olddir, char *oldname,
+static long	ARGS_ON_STACK uni_rename	P_((fcookie *olddir, char *oldname,
 
 				    fcookie *newdir, const char *newname));
 
-static long	uni_opendir	P_((DIR *dirh, int flags));
+static long	ARGS_ON_STACK uni_opendir	P_((DIR *dirh, int flags));
 
-static long	uni_readdir	P_((DIR *dirh, char *nm, int nmlen, fcookie *));
+static long	ARGS_ON_STACK uni_readdir	P_((DIR *dirh, char *nm, int nmlen, fcookie *));
 
-static long	uni_rewinddir	P_((DIR *dirh));
+static long	ARGS_ON_STACK uni_rewinddir	P_((DIR *dirh));
 
-static long	uni_closedir	P_((DIR *dirh));
+static long	ARGS_ON_STACK uni_closedir	P_((DIR *dirh));
 
-static long	uni_pathconf	P_((fcookie *dir, int which));
+static long	ARGS_ON_STACK uni_pathconf	P_((fcookie *dir, int which));
 
-static long	uni_dfree	P_((fcookie *dir, long *buf));
+static long	ARGS_ON_STACK uni_dfree	P_((fcookie *dir, long *buf));
 
-static DEVDRV *	uni_getdev	P_((fcookie *fc, long *devsp));
+static DEVDRV *	ARGS_ON_STACK uni_getdev	P_((fcookie *fc, long *devsp));
 
-static long	uni_symlink	P_((fcookie *dir, const char *name, const char *to));
+static long	ARGS_ON_STACK uni_symlink	P_((fcookie *dir, const char *name, const char *to));
 
-static long	uni_readlink	P_((fcookie *fc, char *buf, int buflen));
+static long	ARGS_ON_STACK uni_readlink	P_((fcookie *fc, char *buf, int buflen));
+
+static long	ARGS_ON_STACK uni_fscntl	P_((fcookie *dir, const char *name, int cmd, long arg));
 
 
 
@@ -66,7 +74,7 @@ FILESYS uni_filesys = {
 
 	(FILESYS *)0,
 
-	0,
+	FS_LONGPATH,
 
 	uni_root,
 
@@ -80,7 +88,7 @@ FILESYS uni_filesys = {
 
 	uni_pathconf, uni_dfree, nowritelabel, noreadlabel,
 
-	uni_symlink, uni_readlink, nohardlink, nofscntl, nodskchng
+	uni_symlink, uni_readlink, nohardlink, uni_fscntl, nodskchng
 
 };
 
@@ -110,7 +118,7 @@ typedef struct unifile {
 
 	char name[NAME_MAX+1];
 
-	short mode;
+	ushort mode;
 
 	ushort dev;
 
@@ -120,17 +128,43 @@ typedef struct unifile {
 
 	struct unifile *next;
 
+	short cdate, ctime;
+
 } UNIFILE;
 
 
 
-/* the "+1" is for shared memory, which has no BIOS drive */
+static UNIFILE u_drvs[UNI_NUM_DRVS];
+
+static UNIFILE *u_root = 0;
 
-#define UNI_DIRS NUM_DRIVES+1
 
-static UNIFILE u_drvs[UNI_DIRS];
 
-static UNIFILE *u_root = 0;
+static long	do_ulookup	P_((fcookie *, const char *, fcookie *, UNIFILE **));
+
+
+
+FILESYS *
+
+get_filesys (dev)
+
+     int dev;
+
+{
+
+  UNIFILE *u;
+
+
+
+  for (u = u_root; u; u = u->next)
+
+    if (u->dev == dev)
+
+      return u->fs;
+
+  return (FILESYS *) 0L;
+
+}
 
 
 
@@ -148,7 +182,7 @@ unifs_init()
 
 	u_root = u;
 
-	for (i = 0; i < NUM_DRIVES; i++,u++) {
+	for (i = 0; i < UNI_NUM_DRVS; i++,u++) {
 
 		u->next = u+1;
 
@@ -156,49 +190,59 @@ unifs_init()
 
 		u->dev = i;
 
-		u->fs = 0;
+		u->cdate = datestamp;
 
-		if (i == PROCDRV)
+		u->ctime = timestamp;
+
+		if (i == PROCDRV) {
 
 			strcpy(u->name, "proc");
 
-		else if (i == PIPEDRV)
+			u->fs = &proc_filesys;
+
+		} else if (i == PIPEDRV) {
 
 			strcpy(u->name, "pipe");
 
-		else if (i == BIOSDRV)
+			u->fs = &pipe_filesys;
+
+		} else if (i == BIOSDRV) {
 
 			strcpy(u->name, "dev");
 
-		else if (i == UNIDRV) {
+			u->fs = &bios_filesys;
+
+		} else if (i == UNIDRV) {
 
 			(u-1)->next = u->next;	/* skip this drive */
 
+		} else if (i == SHMDRV) {
+
+			strcpy(u->name, "shm");
+
+			u->fs = &shm_filesys;
+
 		} else {
 
 			u->name[0] = i + 'a';
 
 			u->name[1] = 0;
 
+			u->fs = 0;
+
 		}
 
 	}
 
-	u->next = 0;
-
-	u->mode = S_IFDIR|DEFAULT_DIRMODE;
-
-	u->dev = SHMDEVICE;
-
-	u->fs = &shm_filesys;
+	--u;	/* oops, we went too far */
 
-	strcpy(u->name, "shm");
+	u->next = 0;
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_root(drv, fc)
 
@@ -228,7 +272,7 @@ uni_root(drv, fc)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_lookup(dir, name, fc)
 
@@ -240,23 +284,51 @@ uni_lookup(dir, name, fc)
 
 {
 
+	return do_ulookup(dir, name, fc, (UNIFILE **)0);
+
+}
+
+
+
+/* worker function for uni_lookup; can also return the UNIFILE
+
+ * pointer for the root directory
+
+ */
+
+static long
+
+do_ulookup(dir, name, fc, up)
+
+	fcookie *dir;
+
+	const char *name;
+
+	fcookie *fc;
+
+	UNIFILE **up;
+
+{
+
 	UNIFILE *u;
 
 	long drvs;
 
 	FILESYS *fs;
 
+	fcookie *tmp;
+
 	extern long dosdrvs;
 
 
 
-	TRACE("uni_lookup(%s)", name);
+	TRACE(("uni_lookup(%s)", name));
 
 
 
 	if (dir->index != 0) {
 
-		DEBUG("uni_lookup: bad directory");
+		DEBUG(("uni_lookup: bad directory"));
 
 		return EPTHNF;
 
@@ -270,7 +342,7 @@ uni_lookup(dir, name, fc)
 
 	if (!*name || !strcmp(name, ".") || !strcmp(name, "..")) {
 
-		*fc = *dir;
+		dup_cookie(fc, dir);
 
 		return 0;
 
@@ -286,7 +358,7 @@ uni_lookup(dir, name, fc)
 
 	for (u = u_root; u; u = u->next) {
 
-		if (!stricmp(name, u->name)) {
+		if (!strnicmp(name, u->name, NAME_MAX)) {
 
 			if ( (u->mode & S_IFMT) == S_IFDIR ) {
 
@@ -294,6 +366,8 @@ uni_lookup(dir, name, fc)
 
 					fs = u->fs;
 
+					if (up) *up = u;
+
 					return (*fs->root)(u->dev,fc);
 
 				}
@@ -302,20 +376,22 @@ uni_lookup(dir, name, fc)
 
 					return EPTHNF;
 
-				*fc = curproc->root[u->dev];
+				tmp = &curproc->root[u->dev];
 
-				if (!fc->fs) {		/* drive changed? */
+				if (!tmp->fs) {		/* drive changed? */
 
-					changedrv(fc->dev);
+					changedrv(tmp->dev);
 
-					*fc = curproc->root[u->dev];
+					tmp = &curproc->root[u->dev];
 
-					if (!fc->fs)
+					if (!tmp->fs)
 
 						return EPTHNF;
 
 				}
 
+				dup_cookie(fc, tmp);
+
 			} else {		/* a symbolic link */
 
 				fc->fs = &uni_filesys;
@@ -326,13 +402,15 @@ uni_lookup(dir, name, fc)
 
 			}
 
+			if (up) *up = u;
+
 			return 0;
 
 		}
 
 	}
 
-	DEBUG("uni_lookup: name (%s) not found", name);
+	DEBUG(("uni_lookup: name (%s) not found", name));
 
 	return EFILNF;
 
@@ -340,7 +418,7 @@ uni_lookup(dir, name, fc)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_getxattr(fc, xattr)
 
@@ -366,7 +444,7 @@ uni_getxattr(fc, xattr)
 
 	xattr->index = fc->index;
 
-	xattr->dev = fc->dev;
+	xattr->dev = xattr->rdev = fc->dev;
 
 	xattr->nlink = 1;
 
@@ -404,9 +482,9 @@ uni_getxattr(fc, xattr)
 
 	}
 
-	xattr->mtime = xattr->atime = xattr->ctime = 0;
+	xattr->mtime = xattr->atime = xattr->ctime = u->ctime;
 
-	xattr->mdate = xattr->adate = xattr->cdate = 0;
+	xattr->mdate = xattr->adate = xattr->cdate = u->cdate;
 
 	return 0;
 
@@ -414,7 +492,7 @@ uni_getxattr(fc, xattr)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_chattr(dir, attrib)
 
@@ -424,13 +502,15 @@ uni_chattr(dir, attrib)
 
 {
 
+	UNUSED(dir); UNUSED(attrib);
+
 	return EACCDN;
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_chown(dir, uid, gid)
 
@@ -440,13 +520,17 @@ uni_chown(dir, uid, gid)
 
 {
 
+	UNUSED(dir); UNUSED(uid);
+
+	UNUSED(gid);
+
 	return EINVFN;
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_chmode(dir, mode)
 
@@ -456,13 +540,17 @@ uni_chmode(dir, mode)
 
 {
 
+	UNUSED(dir);
+
+	UNUSED(mode);
+
 	return EINVFN;
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_rmdir(dir, name)
 
@@ -486,7 +574,7 @@ uni_rmdir(dir, name)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_remove(dir, name)
 
@@ -500,16 +588,24 @@ uni_remove(dir, name)
 
 
 
+	UNUSED(dir);
+
+
+
 	lastu = 0;
 
 	u = u_root;
 
 	while (u) {
 
-		if (!strncmp(u->name, name, NAME_MAX)) {
+		if (!strnicmp(u->name, name, NAME_MAX)) {
 
 			if ( (u->mode & S_IFMT) != S_IFLNK ) return EFILNF;
 
+			if (curproc->euid && (u->dev != curproc->euid))
+
+				return EACCDN;
+
 			kfree(u->data);
 
 			if (lastu)
@@ -538,12 +634,14 @@ uni_remove(dir, name)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
-uni_getname(root, dir, pathname)
+uni_getname(root, dir, pathname, size)
 
 	fcookie *root, *dir; char *pathname;
 
+	int size;
+
 {
 
 	FILESYS *fs;
@@ -554,6 +652,18 @@ uni_getname(root, dir, pathname)
 
 	fcookie relto;
 
+	char tmppath[PATH_MAX];
+
+	long r;
+
+
+
+	UNUSED(root);
+
+
+
+	if (size <= 0) return ERANGE;
+
 
 
 	fs = dir->fs;
@@ -574,10 +684,16 @@ uni_getname(root, dir, pathname)
 
 			*pathname++ = '\\';
 
-			for (n = u->name; *n; )
+			if (--size <= 0) return ERANGE;
+
+			for (n = u->name; *n; ) {
 
 				*pathname++ = *n++;
 
+				if (--size <= 0) return ERANGE;
+
+			}
+
 			break;
 
 		}
@@ -600,11 +716,41 @@ uni_getname(root, dir, pathname)
 
 		if ((*fs->root)(dir->dev, &relto) == 0) {
 
-			return (*fs->getname)(&relto, dir, pathname);
+			if (!(fs->fsflags & FS_LONGPATH)) {
+
+				r = (*fs->getname)(&relto, dir, tmppath, PATH_MAX);
+
+				release_cookie(&relto);
+
+				if (r) {
+
+					return r;
+
+				}
+
+				if (strlen(tmppath) < size) {
+
+					strcpy(pathname, tmppath);
+
+					return 0;
+
+				} else {
+
+					return ERANGE;
+
+				}
+
+			}
+
+			r = (*fs->getname)(&relto, dir, pathname, size);
+
+			release_cookie(&relto);
+
+			return r;
 
 		} else {
 
-			*pathname++ = 0;
+			*pathname = 0;
 
 			return EINTRN;
 
@@ -624,13 +770,41 @@ uni_getname(root, dir, pathname)
 
 
 
-	return (*fs->getname)(&curproc->root[dir->dev], dir, pathname);
+	if (!fs) {
+
+		*pathname = 0;
+
+		return 0;
+
+	}
+
+	if (!(fs->fsflags & FS_LONGPATH)) {
+
+		r = (*fs->getname)(&curproc->root[dir->dev], dir, tmppath, PATH_MAX);
+
+		if (r) return r;
+
+		if (strlen(tmppath) < size) {
+
+			strcpy(pathname, tmppath);
+
+			return 0;
+
+		} else {
+
+			return ERANGE;
+
+		}
+
+	}
+
+	return (*fs->getname)(&curproc->root[dir->dev], dir, pathname, size);
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_rename(olddir, oldname, newdir, newname)
 
@@ -644,7 +818,7 @@ uni_rename(olddir, oldname, newdir, newn
 
 {
 
-	UNIFILE *u = 0;
+	UNIFILE *u;
 
 	fcookie fc;
 
@@ -652,9 +826,13 @@ uni_rename(olddir, oldname, newdir, newn
 
 
 
+	UNUSED(olddir);
+
+
+
 	for (u = u_root; u; u = u->next) {
 
-		if (!stricmp(u->name, oldname))
+		if (!strnicmp(u->name, oldname, NAME_MAX))
 
 			break;
 
@@ -664,7 +842,7 @@ uni_rename(olddir, oldname, newdir, newn
 
 	if (!u) {
 
-		DEBUG("uni_rename: old file not found");
+		DEBUG(("uni_rename: old file not found"));
 
 		return EFILNF;
 
@@ -676,9 +854,15 @@ uni_rename(olddir, oldname, newdir, newn
 
 	r = uni_lookup(newdir, newname, &fc);
 
+	if (r == 0)
+
+		release_cookie(&fc);
+
+
+
 	if (r != EFILNF) {
 
-		DEBUG("uni_rename: error %ld", r);
+		DEBUG(("uni_rename: error %ld", r));
 
 		return (r == 0) ? EACCDN : r;
 
@@ -694,7 +878,7 @@ uni_rename(olddir, oldname, newdir, newn
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_opendir(dirh, flags)
 
@@ -704,9 +888,13 @@ uni_opendir(dirh, flags)
 
 {
 
+	UNUSED(flags);
+
+
+
 	if (dirh->fc.index != 0) {
 
-		DEBUG("uni_opendir: bad directory");
+		DEBUG(("uni_opendir: bad directory"));
 
 		return EPTHNF;
 
@@ -722,7 +910,7 @@ uni_opendir(dirh, flags)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_readdir(dirh, name, namelen, fc)
 
@@ -812,7 +1000,7 @@ tryagain:
 
 		    }
 
-		    *fc = curproc->root[u->dev];
+		    dup_cookie(fc, &curproc->root[u->dev]);
 
 		    if (!fc->fs) {	/* drive not yet initialized */
 
@@ -842,9 +1030,15 @@ tryagain:
 
 	if (giveindex) {
 
-		namelen -= sizeof(long);
+		namelen -= (int)sizeof(long);
 
-		if (namelen <= 0) return ERANGE;
+		if (namelen <= 0) {
+
+			release_cookie(fc);
+
+			return ERANGE;
+
+		}
 
 		*((long *)name) = index;
 
@@ -854,17 +1048,21 @@ tryagain:
 
 	strncpy(name, dirname, namelen-1);
 
-	if (strlen(name) < strlen(dirname))
+	if (strlen(name) < strlen(dirname)) {
+
+		release_cookie(fc);
 
 		return ENAMETOOLONG;
 
+	}
+
 	return 0;
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_rewinddir(dirh)
 
@@ -880,7 +1078,7 @@ uni_rewinddir(dirh)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_closedir(dirh)
 
@@ -888,13 +1086,15 @@ uni_closedir(dirh)
 
 {
 
+	UNUSED(dirh);
+
 	return 0;
 
 }
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_pathconf(dir, which)
 
@@ -904,6 +1104,10 @@ uni_pathconf(dir, which)
 
 {
 
+	UNUSED(dir);
+
+
+
 	switch(which) {
 
 	case -1:
@@ -938,6 +1142,14 @@ uni_pathconf(dir, which)
 
 		return DP_CASEINSENS;
 
+	case DP_MODEATTR:
+
+		return DP_FT_DIR|DP_FT_LNK;
+
+	case DP_XATTRFIELDS:
+
+		return DP_INDEX|DP_DEV|DP_NLINK|DP_SIZE;
+
 	default:
 
 		return EINVFN;
@@ -948,7 +1160,7 @@ uni_pathconf(dir, which)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_dfree(dir, buf)
 
@@ -958,6 +1170,10 @@ uni_dfree(dir, buf)
 
 {
 
+	UNUSED(dir);
+
+
+
 	buf[0] = 0;	/* number of free clusters */
 
 	buf[1] = 0;	/* total number of clusters */
@@ -972,7 +1188,7 @@ uni_dfree(dir, buf)
 
 
 
-static DEVDRV *
+static DEVDRV * ARGS_ON_STACK 
 
 uni_getdev(fc, devsp)
 
@@ -982,6 +1198,10 @@ uni_getdev(fc, devsp)
 
 {
 
+	UNUSED(fc);
+
+
+
 	*devsp = EACCDN;
 
 	return 0;
@@ -990,7 +1210,7 @@ uni_getdev(fc, devsp)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_symlink(dir, name, to)
 
@@ -1012,12 +1232,24 @@ uni_symlink(dir, name, to)
 
 	r = uni_lookup(dir, name, &fc);
 
-	if (r == 0) return EACCDN;	/* file already exists */
+	if (r == 0) {
+
+		release_cookie(&fc);
+
+		return EACCDN;	/* file already exists */
+
+	}
 
 	if (r != EFILNF) return r;	/* some other error */
 
 
 
+	if (curproc->egid)
+
+		return EACCDN;	/* only members of admin group may do that */
+
+
+
 	u = kmalloc(SIZEOF(UNIFILE));
 
 	if (!u) return EACCDN;
@@ -1044,12 +1276,16 @@ uni_symlink(dir, name, to)
 
 	u->mode = S_IFLNK | DEFAULT_DIRMODE;
 
-	u->dev = curproc->ruid;
+	u->dev = curproc->euid;
 
 	u->next = u_root;
 
 	u->fs = &uni_filesys;
 
+	u->cdate = datestamp;
+
+	u->ctime = timestamp;
+
 	u_root = u;
 
 	return 0;
@@ -1058,7 +1294,7 @@ uni_symlink(dir, name, to)
 
 
 
-static long
+static long ARGS_ON_STACK 
 
 uni_readlink(fc, buf, buflen)
 
@@ -1092,3 +1328,323 @@ uni_readlink(fc, buf, buflen)
 
 }
 
+
+
+
+
+
+
+
+
+/* uk: use these Dcntl's to install a new filesystem which is only visible
+
+ *     on drive u:
+
+ *
+
+ *     FS_INSTALL:   let the kernel know about the file system; it does NOT
+
+ *                   get a device number.
+
+ *     FS_MOUNT:     use Dcntl(FS_MOUNT, "u:\\foo", &descr) to make a directory
+
+ *                   foo where the filesytem resides in; the file system now
+
+ *                   gets its device number which is also written into the
+
+ *                   dev_no field of the fs_descr structure.
+
+ *     FS_UNMOUNT:   remove a file system's directory; this call closes all
+
+ *                   open files, directory searches and directories on this
+
+ *                   device. Make sure that the FS will not recognise any
+
+ *                   accesses to this device, as fs->root will be called
+
+ *                   during the reinitalisation!
+
+ *     FS_UNINSTALL: remove a file system completely from the kernel list,
+
+ *                   but that will only be possible if there is no directory
+
+ *                   associated with this file system.
+
+ *                   This function allows it to write file systems as demons
+
+ *                   which stay in memory only as long as needed.
+
+ *
+
+ * BUG: it is not possible yet to lock such a filesystem.
+
+ */
+
+
+
+/* here we start with gemdos only file system device numbers */
+
+static curr_dev_no = 0x100;
+
+
+
+
+
+
+
+static long ARGS_ON_STACK
+
+uni_fscntl(dir, name, cmd, arg)
+
+	fcookie *dir;
+
+	const char *name;
+
+	int cmd;
+
+	long arg;
+
+{
+
+	fcookie fc;
+
+	long r;
+
+
+
+	extern struct kerinfo kernelinfo;
+
+	extern FILESYS *active_fs;
+
+
+
+	if (cmd == (int)FS_INSTALL) { /* install a new filesystem */
+
+		struct fs_descr *d = (struct fs_descr*)arg;
+
+		FILESYS *fs;
+
+
+
+	/* check if FS is installed already */
+
+		for (fs = active_fs;  fs;  fs = fs->next)
+
+			if (d->file_system == fs)  return 0L;
+
+	/* include new file system into chain of file systems */
+
+		d->file_system->next = active_fs;
+
+		active_fs = d->file_system;
+
+		return (long)&kernelinfo;  /* return pointer to kernel info as OK */
+
+	} else if (cmd == (int)FS_MOUNT) {  /* install a new gemdos-only device for this FS */
+
+		struct fs_descr *d = (struct fs_descr*)arg;
+
+		FILESYS *fs;
+
+		UNIFILE *u;
+
+
+
+	/* first check for existing names */
+
+		r = uni_lookup(dir, name, &fc);
+
+		if (r == 0) {
+
+			release_cookie(&fc);
+
+			return EACCDN;   /* name exists already */
+
+		}
+
+		if (r != EFILNF) return r; /* some other error */
+
+		if (!d) return EACCDN;
+
+		if (!d->file_system) return EACCDN;
+
+	/* check if FS is installed */
+
+		for (fs = active_fs;  fs;  fs = fs->next)
+
+			if (d->file_system == fs)  break;
+
+		if (!fs) return EACCDN;  /* not installed, so return an error */
+
+		u = kmalloc(SIZEOF(UNIFILE));
+
+		if (!u) return EACCDN;
+
+		strncpy(u->name, name, NAME_MAX);
+
+		u->name[NAME_MAX] = 0;
+
+		u->mode = S_IFDIR|DEFAULT_DIRMODE;
+
+		u->data = 0;
+
+		u->fs = d->file_system;
+
+	/* now get the file system its own device number */
+
+		u->dev = d->dev_no = curr_dev_no++;
+
+	/* chain new entry into unifile list */
+
+		u->next = u_root;
+
+		u_root = u;
+
+		return (long)u->dev;
+
+	} else if (cmd == (int)FS_UNMOUNT) {  /* remove a file system's directory */
+
+		struct fs_descr *d = (struct fs_descr*)arg;
+
+		FILESYS *fs;
+
+		UNIFILE *u;
+
+
+
+	/* first check that directory exists */
+
+	/* use special uni_lookup mode to get the unifile entry */
+
+		r = do_ulookup(dir, name, &fc, &u);
+
+		if (r != 0)  return EFILNF;   /* name does not exist */
+
+		if (!d) return EFILNF;
+
+		if (!d->file_system) return EFILNF;
+
+		if (d->file_system != fc.fs)
+
+			return EFILNF;  /* not the right name! */
+
+		release_cookie(&fc);
+
+
+
+		if (!u || (u->fs != d->file_system))
+
+			return EFILNF;
+
+	/* check if FS is installed */
+
+		for (fs = active_fs;  fs;  fs = fs->next)
+
+			if (d->file_system == fs)  break;
+
+		if (!fs) return EACCDN;  /* not installed, so return an error */
+
+
+
+	/* here comes the difficult part: we have to close all files on that
+
+	 * device, so we have to call changedrv(). The file system driver
+
+	 * has to make sure that further calls to fs.root() with this device
+
+	 * number will fail!
+
+	 *
+
+	 * Kludge: mark the directory as a link, so uni_remove will remove it.
+
+	 */
+
+		changedrv(u->dev);
+
+		u->mode &= ~S_IFMT;
+
+		u->mode |= S_IFLNK;
+
+		return uni_remove(dir, name);
+
+	} else if (cmd == (int)FS_UNINSTALL) {    /* remove file system from kernel list */
+
+		struct fs_descr *d = (struct fs_descr*)arg;
+
+		FILESYS *fs, *last_fs;
+
+		UNIFILE *u;
+
+
+
+	/* first check if there are any files or directories associated with
+
+	 * this file system
+
+	 */
+
+		for (u = u_root;  u;  u = u->next)
+
+			if (u->fs == d->file_system)
+
+				return EACCDN;   /* we cannot remove it before unmount */
+
+		last_fs = 0;
+
+		fs = active_fs;
+
+		while (fs)  {   /* go through the list and remove the file system */
+
+			if (fs == d->file_system)  {
+
+				if (last_fs)
+
+					last_fs->next = fs->next;
+
+				else
+
+					active_fs = fs->next;
+
+				d->file_system->next = 0;
+
+				return 0;
+
+			}
+
+			last_fs = fs;
+
+			fs = fs->next;
+
+		}
+
+		return EFILNF;
+
+	} else {
+
+	/* see if we should just pass this along to another file system */
+
+		r = uni_lookup(dir, name, &fc);
+
+		if (r == 0) {
+
+			if (fc.fs != &uni_filesys) {
+
+				r = (*fc.fs->fscntl)(&fc, ".", cmd, arg);
+
+				release_cookie(&fc);
+
+				return r;
+
+			}
+
+			release_cookie(&fc);
+
+		}
+
+	}
+
+	return EINVFN;
+
+}
+