This patch alleviates the need for any non-core process to create Unix
domain sockets locally. All sockets used for RPC communication are
created by core and subsequently passed to the other processes via RPC
or the parent interface. The immediate benefit is that no process other
than core needs to access the 'rpath' directory in order to communicate.
However, access to 'rpath' is still needed for accessing dataspaces.
Core creates one socket pair per thread on demand on the first call of
the 'Linux_cpu_session::server_sd()' or 'Linux_cpu_session::client_sd()'
functions. 'Linux_cpu_session' is a Linux-specific extension to the CPU
session interface. In addition to the socket accessors, the extension
provides a mechanism to register the PID/TID of a thread. Those
information were formerly propagated into core along with the thread
name as argument to 'create_thread()'.
Because core creates socket pairs for entrypoints, it needs to know all
threads that are potential entrypoints. For lx_hybrid programs, we
hadn't had propagated any thread information into core, yet. Hence, this
patch also contains the code for registering threads of hybrid
applications at core.
This patch eliminates the thread ID portion of the 'Native_capability'
type. The access to entrypoints is now exclusively handled by passing
socket descripts over Unix domain sockets and by inheriting the socket
descriptor of the parent entrypoint at process-creation time.
Each entrypoint creates a socket pair. The server-side socket is bound
to a unique name defined by the server. The client-side socket is then
connected to the same name. Whereas the server-side socket is meant to
be exclusively used by the server to wait for incoming requests, the
client-side socket can be delegated to other processes as payload of RPC
messages (via SCM rights). Anyone who receives a capability over RPC
receives the client-side socket of the entrypoint to which the
capability refers. Given this socket descriptor, the unique name (as
defined by the server) can be requested using 'getpeername'. Using this
name, it is possible to compare socket descriptors, which is important
to avoid duplicates from polluting the limited socket-descriptor name
space.
Wheras this patch introduces capability-based delegation of access
rights to entrypoints, it does not cover the protection of the integrity
of RPC objects. RPC objects are still referenced by a global ID passed
as normal message payload.
This patch adds prinicipal support for transmitting socket descriptors
as RPC payload. Socket descriptors are handled by the linux-specific
implementation of the capability marshalling and unmarshalling functions
in 'ipc.h'. The 'Message' type in 'src/platform/linux_socket.h' has been
extended to carry multiple descriptors in a single message.
Unfortuately, we hit a problem (and potential show stopper) here:
lx_sendmsg failed with -109 in lx_call()
The error code corresponds to ETOOMANYREFS. There is only one place in
the Linux kernel where this error code is used (net/unix/af_unix.c).
The code for 'unix_attach_fds()' suggests that there is a limit with
regard to the maximum number of references for a given Unix domain
socket. When the error occurs, core and init are running. The socket
of core's server entrypoint is present in the '/proc/pid/fd' of those
processes 8 times. The error occurs when core tries to perform an
RPC to the entrypoint to perform 'Ram_session::transfer_quota()'
(base/include/base/child.h at line 248).
By storing the reply socket descriptor inside the 'Ipc_ostream::_dst'
capability instead as part of the connection state object, we can
use the 'explicit_reply' mechanism as usual. Right now, we store
both the tid and socket handle in 'Native_capability::Dst'. In the
final version, the 'tid' member will be gone.
In the final version, the 'socket' will be the only member to remain in
the 'Dst' time. In the transition phase, we store both the old 'tid' and
the 'socket'.
This patch, which was originally created by Christian Helmuth,
represents the first step towards using SCM rights as capability
mechanism on Linux. It employs the SCM rights mechanism for transmitting
a reply capability to the server as argument of each IPC call. The
server will then send its respond to this reply file descriptor. This
way, the reply channel does not need to be globally visible anymore.
The bash-builtin 'pwd' command uses the 'st_dev' and 'st_ino' members of
the 'stat' struct to compare the path from the 'PWD' environment variable
with the path returned by 'getcwd()'. These members don't get set
correctly in Noux and therefore the 'pwd' command sometimes returns wrong
results when building Genode in Noux. With this patch the 'CURDIR' make
variable gets used instead of calling 'pwd'.
Fixes#454.
With this patch an error message gets printed in
'Allocator_avl_base::free()' if the given address is not the start address
of the allocated block.
Fixes#459.
Create the signal context object before the signal receiver object to get the
signal receiver destroyed before the signal context. This avoids a 'specified
signal-context capability has wrong type' warning when the signal receiver
tries to free its managed context on destruction.
Part of #448.
When building the Fiasco.OC kernel, and L4Linux within the Genode build system,
forward the CC, and CXX variables. It might contain useful tools like ccache,
or distcc to speed up compilation. Moreover, don't delete the MAKEFLAGS when
building Fiasco.OC. It hinders parallel builds.
Certain symbols from the libgcc_eh library in cxx that is linked with the
L4Linux kernel were resolved by using kernel internal implementations.
This lead to errors because the complete Linux kernel is built regparm=3.
This patch prefixes the appropriate symbols in the Linux Kernel and its
modules. Moreover, it fixes some warnings introduced by the latest update
to gcc 4.7.
g++ 4.4.5 outputs the following warnings in our code using the loader
session:
.../base/include/base/capability.h: In member function 'typename Genode::Trait::Call_return<typename IF::Ret_type>::Type Genode::Capability<RPC_INTERFACE>::call() const [with IF = Loader::Session::Rpc_view_geometry, RPC_INTERFACE = Loader::Session]':
.../base/include/base/capability.h:207: warning: 'ret.Genode::Capability<Loader::Session>::Return<Loader::Session::Rpc_view_geometry>::_value.Loader::Session::View_geometry::width' may be used uninitialized in this function
.../base/include/base/capability.h:207: warning: 'ret.Genode::Capability<Loader::Session>::Return<Loader::Session::Rpc_view_geometry>::_value.Loader::Session::View_geometry::height' may be used uninitialized in this function
.../base/include/base/capability.h:207: warning: 'ret.Genode::Capability<Loader::Session>::Return<Loader::Session::Rpc_view_geometry>::_value.Loader::Session::View_geometry::buf_x' may be used uninitialized in this function
.../base/include/base/capability.h:207: warning: 'ret.Genode::Capability<Loader::Session>::Return<Loader::Session::Rpc_view_geometry>::_value.Loader::Session::View_geometry::buf_y' may be used uninitialized in this function
This is easily fixed with providing a default constructor.
Because of the C++ rules regarding initialer lists code that used
them for View_geometry had to be modified to use a normal construction
call. In my tests only Nitpicker had to be changed.
Preparation of base-pistachio fails on Ubuntu with dash as /bin/sh as it
does not support non-POSIX features like brace expansion. In this case
expanding in the Makefile via $(addprefix ...) fixes this shortcoming.
With the update to L4ka::Pistachio, we no longer need to patch the
contrib sources. Our patch went upstream in the meanwhile.
Apparently, gcc-4.7 is picky about specifying the '-melf_i386' argument
at the command line of the GCC frontend. We need to make sure to use the
'-Wl,' prefix.
The eglgears application depends on 'sqrt'. With the old tool chain,
this symbol was resolved through the dependencies of the 'gallium'
library. This does not work anymore for the new tool chain.
A similar issue arised for avplay, where we need to explicitly
state the av components in the LIBS declaration of the target.
The terminal has a lot of bits that may be worth reusing outside the
single implementation. Those bits are now located at 'include/terminal'
in the gems repository.
Replacing the local name of a capability index object which exists in the
capability map can destroy the AVL tree order of the capability map. With
this patch the outdated object gets removed from the map and a new object
gets inserted afterwards.
Fixes#435.
After this commit "make prepare" uses HTTP, HTTPS, or FTP where possible
fvor downloading third-party source codes. This prevents problems with
strict firewall rules where only selected ports are usable.
Unfortunately, git.l4android.org does not support Git via HTTP and,
therefore, the sources need a working Git port (9418).
Fixes#443.
