Libc components cannot use regular calls to select() as this may suspend
their execution. In this case incoming RPCs will be deferred until
select() returns and the component returns to the entrypoint dispatch
loop. The Libc::Signal_handler solves this problem with a its select()
that either returns the currently ready file descriptors immediately or
calls the registered handler function during libc resume.
This commit extends an easy-to-use mechanism to allow Genode component
code to enter/leave the libc application context. This is needed
whenever low-level component code (like signal handlers or RPC
functions) need to interact with potentially blocking libc I/O
functions.
Please note that this commit contains the API-level design only. The
actual context switching code 'execute_in_application_context' is
missing.
The socket file system can be configured in the "socket" attribute of
the libc config node like follows.
<vfs> <dir name="socket"> <fs/> </dir> </vfs>
<libc ... socket="/socket"/>
This configures the socket file system libc backend to access files in
"/socket" for socket operations.
A binary file may be a temporary Vim .swp file when examining contrib
sources. The commit prevents build errors like
.../repos/dde_linux/lib/mk/lxip_include.mk:29:
target '.../x86_64/var/libcache/lxip_include/include/include/include/Binary'
given more than once in the same rule
.../repos/dde_linux/lib/mk/lxip_include.mk:29:
target '.../x86_64/var/libcache/lxip_include/include/include/include/file'
given more than once in the same rule
...
Libc::Env is the Genode::Env interface extended to cover access
to the XML content of the 'config' ROM and a VFS instance. This
deduplicates the burden of components to attain and manage
these resources.
Fix#2217
Ref #1987
This aspect was always enabled when creating a build directory for hw,
but is not enabled anymore due to recent build directory unifications.
On the other hand it is needed for jitter entropy anyway.
Ref #2190
This patch make the ABI mechanism available to shared libraries other
than Genode's dynamic linker. It thereby allows us to introduce
intermediate ABIs at the granularity of shared libraries. This is useful
for slow-moving ABIs such as the libc's interface but it will also
become handy for the package management.
To implement the feature, the build system had to be streamlined a bit.
In particular, archive dependencies and shared-lib dependencies are now
handled separately, and the global list of 'SHARED_LIBS' is no more.
Now, the variable with the same name holds the per-target list of shared
libraries used by the target.
This patch removes the component_entry_point library, which used to
proved a hook for the libc to intercept the call of the
'Component::construct' function. The mechansim has several shortcomings
(see the discussion in the associated issue) and was complex. So we
eventually discarded the approach in favor of the explicit handling of
the startup.
A regular Genode component provides a 'Component::construct' function,
which is determined by the dynamic linker via a symbol lookup.
For the time being, the dynamic linker falls back to looking up a 'main'
function if no 'Component::construct' function could be found.
The libc provides an implementation of 'Component::construct', which
sets up the libc's task handling and finally call the function
'Libc::Component::construct' from the context of the appllication task.
This function is expected to be provided by the libc-using application.
Consequently, Genode components that use the libc have to implement the
'Libc::Component::construct' function.
The new 'posix' library provides an implementation of
'Libc::Component::construct' that calls a main function. Hence, POSIX
programs that merely use the POSIX API merely have to add 'posix' to the
'LIBS' declaration in their 'target.mk' file. Their execution starts at
'main'.
Issue #2199
This patch adjusts the various users of the 'Child' API to the changes
on the account of the new non-blocking parent interface. It also removes
the use of the no-longer-available 'Connection::KEEP_OPEN' feature.
With the adjustment, we took the opportunity to redesign several
components to fit the non-blocking execution model much better, in
particular the demo applications.
Issue #2120
Now rlibs are actually linked to programs. Target files have been
modified to not generate code that requires compiler-rt. Added a target
for libstd-rust, but it's very broken right now. Moved alloc_system to
the libports folder because either a memory allocator needs to be
written in rust or posix_memalign needs to be implemented. Changed
liblibc to use freebsd as the OS instead of netbsd. Added a library with
unwind dummy functions.
Rust relies on atomic builtins, which are not implemented in libgcc for
ARM. One was implemented in rust, which was sufficient to get the
current rust test to run. Rust libs were added into the group of libs
for the linker so order no longer matters. The raspberry pi now uses an
armv6 target.
This commit introduces the new `Component` interface in the form of the
headers base/component.h and base/entrypoint.h. The os/server.h API
has become merely a compatibilty wrapper and will eventually be removed.
The same holds true for os/signal_rpc_dispatcher.h. The mechanism has
moved to base/signal.h and is now called 'Signal_handler'.
Since the patch shuffles headers around, please do a 'make clean' in the
build directory.
Issue #1832
Rust relies on atomic builtins, which are not implemented in libgcc for
ARM. One is implemented in rust, which is sufficient to get the
current rust test to run.
Issue #1899
