This patch removes the hardcoded parent cap for the new child by
introducing a facility called 'poke' similar to copy-to-user. This
change makes the fork mechanism kernel-agnostic. The 'noux_fork'
test works on L4/Fiasco, OKL4, NOVA, Fiasco.OC, and L4ka::Pistachio.
Linux is not supported yet.
The resource virtualization layer has been extended to support sub RM
sessions because this feature is used by the dynamic linker. Currently,
the address space of the forking process is copied eagerly. However,
different dataspace types are treated differently. For example, only RAM
dataspaces are copied but no ROM dataspaces.
At the libc side, a setjmp/longjmp-based trampoline mechanism is used to
implement the continuation of the main thread inside the new process.
This procedure is also responsible for re-establishing the relationship
to the new process' parent as well as its Noux session.
This version is still in flux and has many rough edges. It is tied to
OKL4 for now.
Because 'Noux::Child' implements several abstract Genode interfaces, the
'Genode::' prefix became almost ubiquitous, making the code harder to
read. By importing the 'Genode' namespace into the 'Noux' namespace,
this patch remedies this inconvenience.
To implement fork semantics, we need to customize the bootstrapping of
the newly created process, in particular the startup of the main thread.
The CPU session interface provides a suitable hook. By virtualizing the
CPU connection of the process to core, we can defer (and parametrize)
the startup of the main thread. Furthermore, this enables us to detect
illegal attempts by the Noux process to create threads in addition to
the main thread.
By letting Noux processes talk to service implementations local to the
Noux server, we can track RAM allocations and RM operations. This is
needed as a prerequisite to implement fork.
The following features are tested (currently on Fiasco.OC only):
- breakpoint in 'main()'
- breakpoint in a shared library function
- stack trace when not in a syscall
- thread info
- single stepping
- handling of segmention fault exception
- stack trace when in a syscall
This patch fixes#105.
It does not suffice to constrain the amount of returned data with chunk
size of the transport buffer because the client may have specified an
even smaller value. For example, libreadline reads single characters
from the terminal and expects a single character in return. A different
amount is interpreted as EOF.
The patch fixes a corner-case problem with using the two-byte 'INT 0'
instruction for breakpoints. The fix changes the breakpoint instruction
to the single-byte 'HLT'. 'HLT' is a privileged instruction and triggers
an exception when executed in user mode. Patch by Christian Prochaska.
The new 'gdb_monitor_interactive.run' script extends the original
'gdb_monitor.run' script with a startup sequence that automates the
initial break-in at the main function of a dynamically linked binary.
Patch by Christian Prochaska.
When reading the values of environment variables supplied via Genode
config mechanism, the XML attribute values were taken as is. On the libc
side, however, the values are processed using Genode's 'Arg_string'
functions. When unquoted, 'Arg_string' expects values to be either
identifiers or numbers. In the general case, however, env values cannot
be expected to satisfy these requirements. Hence, it is better to always
quote these values when reading the XML config. An alternative (maybe
better) solution would be to not use the 'Arg_string' classes in the
libc side.
This patch sets the ECHO flag for the TIOCGETA ioctrl operation. This
flag is examined by libreadline to control the policy of echoing user
input. This patch in needed to run bash in interactive mode in Noux.
