Traverse translator hierarchies using the fsys protocol.

Previously, we used the fs protocol to traverse the translator
hierarchies.  This, however, is conceptually flawed, because
translators are bound to nodes, and a node can have zero or more links
in the file system.  Therefore, the previous method of returning a
list of paths to the client and expecting them to be able to follow
these to reach the child translators was always unreliable.

Fix this by using the fsys protocol to traverse the hierarchy, and
returning the control ports of all children.  This is more robust, and
also conceptually cleaner, because the fsys protocol is about
translator linkage, hence this is the point to implement traversal.

Also move the get source routine over.  A per-node source really
does not fit the reality of most translators, while a per-translator
source makes sense in many cases.

* hurd/fs.defs (file_get_children): Drop routine.
(file_get_source): Likewise.
* hurd/fsys.defs (fsys_get_children): New routine.
(fsys_get_source): Likewise.
* libdiskfs/Makefile (FSYSSRCS): Remove files, add files.
* libdiskfs/file-get-children.c: Remove file.
* libdiskfs/fsys-get-children.c: New file.
* libdiskfs/file-get-source.c: Remove file.
* libdiskfs/fsys-get-source.c: New file.
* libfshelp/fshelp.h (fshelp_filter): Remove type.
(fshelp_get_active_translators): Remove filter and prefix argument,
return list of control ports.
* libfshelp/translator-list.c (fshelp_get_active_translators):
Likewise.
* libnetfs/Makefile (FSSRCS): Move 'get-source.c' too OTHERSRCS.
(FSYSSRCS): Remove files, add files.
* libnetfs/file-get-children.c: Remove file.
* libnetfs/fsys-get-children.c: New file.
* libnetfs/file-get-source.c: Remove file.
* libnetfs/fsys-get-source.c: New file.
* libtrivfs/Makefile: Move 'get-source.c' too OTHERSRCS.
(FSYSSRCS): Remove files, add files.
* libtrivfs/file-get-children.c: Remove file.
* libtrivfs/fsys-get-children.c: New file.
* libtrivfs/file-get-source.c: Remove file.
* libtrivfs/fsys-get-source.c: Add file.
* trans/Makefile (mtab): Build client stubs until the libc has caught
on.
* trans/mtab.c (target_control): New variable.
(insecure): Drop variable.
(all_translators): Likewise.
(MAX_DEPTH): New macro.
(max_depth): New variable.
(options): Remove '--insecure' and '--all-translators', add '--depth'.
(parse_opt): Adapt accordingly.
(trivsfs_append_args): Likewise.
(main): Get the control port of the target translator, then drop
privileges.
(is_filesystem_translator): Remove function.
(mtab_mark_as_seen): Simplify.  Just check if the control port is
known.
(mtab_populate): Limit depth of recursion, adapt to traversing over
the control ports, simplify.
(open_hook): Remove scary comment, it is not applicable anymore
because we no longer dir_lookup child translators.

1 files changed, 4 insertions, 4 deletions

diff --git a/libnetfs/Makefile b/libnetfs/Makefile
index c3830c03..de06816e 100644
--- a/libnetfs/Makefile
+++ b/libnetfs/Makefile
@@ -34,8 +34,7 @@ FSSRCS= dir-link.c dir-lookup.c dir-mkdir.c dir-mkfile.c \
 	file-get-translator.c file-getcontrol.c file-getlinknode.c \
 	file-lock-stat.c file-lock.c file-set-size.c \
 	file-set-translator.c file-statfs.c file-sync.c file-syncfs.c \
-	file-utimes.c file-reparent.c fsstubs.c	file-get-transcntl.c \
-	get-source.c
+	file-utimes.c file-reparent.c fsstubs.c	file-get-transcntl.c
 
 IOSRCS=	io-read.c io-readable.c io-seek.c io-write.c io-stat.c io-async.c     \
 	io-set-all-openmodes.c io-get-openmodes.c io-set-some-openmodes.c     \
@@ -45,7 +44,7 @@ IOSRCS=	io-read.c io-readable.c io-seek.c io-write.c io-stat.c io-async.c     \
 	io-version.c
 
 FSYSSRCS= fsys-syncfs.c fsys-getroot.c fsys-get-options.c fsys-set-options.c \
-	fsys-goaway.c fsysstubs.c file-get-children.c file-get-source.c
+	fsys-goaway.c fsysstubs.c fsys-get-children.c fsys-get-source.c
 
 IFSOCKSRCS=
 OTHERSRCS= drop-node.c init-init.c make-node.c make-peropen.c make-protid.c   \
@@ -53,7 +52,8 @@ OTHERSRCS= drop-node.c init-init.c make-node.c make-peropen.c make-protid.c   \
 	init-startup.c startup-argp.c set-options.c append-args.c	      \
 	runtime-argp.c std-runtime-argp.c std-startup-argp.c		      \
 	append-std-options.c trans-callback.c set-get-trans.c		      \
-	nref.c nrele.c nput.c file-get-storage-info-default.c dead-name.c
+	nref.c nrele.c nput.c file-get-storage-info-default.c dead-name.c     \
+	get-source.c
 
 SRCS= $(OTHERSRCS) $(FSSRCS) $(IOSRCS) $(FSYSSRCS) $(IFSOCKSRCS)