The kernel provides a "recall" feature issued on threads to force a thread into
an exception. In the exception the current state of the thread can be obtained
and its execution can be halted/paused.
However, the recall exception is only delivered when the next time the thread
would leave the kernel. That means the delivery is asynchronous and Genode has
to wait until the exception triggered.
Waiting for the exception can either be done in the cpu_session service or
outside the service in the protection domain of the caller.
It turned out that waiting inside the cpu_service is prone to deadlock the
system. The cpu_session interface is one of many session interfaces handled by
the same thread inside Core.
Deadlock situation:
* The caller (thread_c) to pause some thread_p manages to establish the call
to the cpu_session thread_s of Core but get be interrupted before issuing
the actual pause (recall) command.
* Now the - to be recalled thread_p - is scheduled and tries to invoke another
service of Core, like making log output.
* Since the Core thread_s is handling the session request of thread_c, the
kernel uses the timeslice of thread_p to help to finish the request handled
by thread_s.
* Thread_s issues the actual pause/recall on thread_p and blocks inside Core
to wait for the recall exception to be issued.
* thread_p will leave not the kernel before finishing it actual IPC with
thread_s which is blocked waiting for thread_p.
That is the reason why the waiting/blocking for the recall exception taking
place must be done on NOVA in the context of the caller (thread_1).
Introduce a pause_sync call to the cpu_session which returns a semaphore
capability to the caller. The caller blocks on the semaphore and is woken up
when the pager of thread_p receives the recall exception with the state of
thread_p.
The 'fd_set' size calculation in the current version of the 'poll()'
function results in an amount which is smaller than the size of the
'fd_set' data type. With this patch the file descriptor sets get
allocated as plain stack variables.
Fixes#335.
This patch implements a service which provides the contents of a tar
archive via the 'File_system::Session' interface.
Configuration:
<config>
<archive name="tar_archive.tar" />
<policy label="label_of_client" root="/rootdir/for/client" />
</config>
Fixes#333.
Certain programs tend to set their sockets non-blocking. As previously
descriptors in Noux were only blocking we now introduce a method to mark
the used Io_channel as non-blocking.
There are certain programms which check if an fd is open by calling
fcntl(fd, F_GETFL, ...). So to keep them happy we return true if
such an request was done to our terminal fd's.
Explanation why --disable-rpath-hack is needed:
When building on pistachio_x86 $(LDFLAGS) contains '-L[...]/l4/lib'
which will be transformed by autoconf to '-rpath [...]/l4/lib'.
Now the problem at hand is that we pretend to be FreeBSD when we are
actually not. So autoconf assumes it is valid to use '-path' when it
is actually not.
Also we use zlib for (de)compressing gzipped streams/files instead of
calling gzip as this currently somewhat buggy.
These device are mandatory for most programs (well, at least null
is required to be present for a POSIX compliant OS, which Noux is
actually not). But for proper shell-script support we will need
them anyway.
There are certain programs which need the information that is stored in
'struct passwd'. This commit introduces configurable user information
support to NOUX.
One can set the user information via <user> in NOUX config:
! <config>
! <user name="baron" uid="1" gid="1">
! <shell name="/bin/bash" />
! <home name="/home" />
! </user>
! [...]
! </config>
When <user> is not specified default values are used. Currently these
are 'root', 0, 0, '/bin/bash', '/'.
Note: this is just a single user implementation because each Noux instance
has only one user or rather one identity and there will be no complete
multi-user support in Noux. If you need different users, just start new
Noux instances for each of them.
Removes getpwent.c from build because the passwd facilities provided by
the FreeBSD libc will not be used anyway and add stub functions instead.
Now services which need these functions have to implement their own
(e.g. libc_noux).
Apparently, GNU make 3.81 picks the generic '%.h' rule instead of the
more specific 'rpc/%.h' rule during the preparation of the libc.
Changing the order of the rules solves the problem.
libc_resolv is a {free,get}addrinfo() plugin, mainly for use with NOUX.
We prefix the original libc functions to with 'libc_' so there is no
symbol conflict with file_operations.cc.
Most of the libs are needed for DNS related stuff. Since we now
have libc_resolv they are not longer needed. Infact they will
lead to undefined symbols so we remove them alltogther as build
dependency for the libc.
Previously there was not actual timeout handling. If a select() call
set an timeout it would be set to zero instead and was always handled
as blocking i/o. While this works fine for file descriptors which
will be triggerd externally (for example vim through terminal i/o) it
does not work at all for socket descriptors and network operations in
general.
So this commit introduces proper timeout handling and changes the
behaviour of SYSCALL_SELECT so that it now returns more than just
one descriptor at a time.
noux/minimal and noux/net now depend on thread and alarm libraries.
Noux used to trace syscalls by default, which significantly slows down
its execution. This patch disables the tracing by default. It can be
enabled by specifying 'trace_syscalls="yes"' attribute to the Noux
configuration.
This patch resolves a problem with running 'noux_gdb.run'. Right at the
start, GDB would output a message like:
...cli-script.c:1614: internal-error: called with NULL file pointer!
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
The LOG output hints at the cause of the problem:
[init -> noux -> /bin/genode-x86-gdb] fcntl: F_GETFL for libc_fd=3
Thanks to cproc for the fix!
