Release v2.3
============
This release is intended more specifically to developers and advanced
users, it was mostly driven by the requirements of an internal
STMicroelectronics project named "Auto-Tuning Optimization Service".
New features
------------
* There's now an extension mechanism in PRoot that allows developers
to add their own features and/or to use PRoot as a Linux process
instrumentation engine. The two following old features were moved
to this new extension interface: "-k *string*" and "-0"
(respectively: set the kernel release and compatibility level to
*string*"; and force some syscalls to behave as if executed by
"root").
* It is now possible to execute PRoot under PRoot, well somewhat.
Actually the initial instance of PRoot detects that it is being
called again and recomputes the configuration for the new process
tree. This feature is still experimental and was way harder to
implement than expected, however it was worth the effort since it
enforced the consistency in PRoot. Just one example among many, in
PRoot the "chroot" feature is now really equivalent to the
"mount/bind" one, that is, ``chroot path/to/rootfs`` is similar to
``mount --bind path/to/rootfs /``.
* The "current working directory" (chdir(2), getcwd(2), ...) is now
fully emulated by PRoot. Sadly a minor regression was introduced:
even if the current working directory has been removed, getcwd(2)
returns a "correct" value. This should be fixed in the next
release.
Command-line interface changes
------------------------------
* The message "proot info: started/exited" isn't printed by default
anymore since it might introduce noise when PRoot is used inside a
test-suite that compares outputs. This message was initially added
to know whether the guest program has exited immediately.
* The "-u" and "-W" options have disappeared. The former wasn't
really useful and the latter was definitely useless since the
default "current working directory" is "." since v2.1, that means
the three examples below are equivalent ("-W" was just an alias to
"-b . -w .")::
proot -b . [...]
proot -b . -w . [...]
proot -W [...]
Fixes
-----
* The option ``-w .`` is now really equivalent to ``-w $PWD``.
* A bug almost impossible to describe here has been fixed, it appeared
only when specifying relative bindings, for instance: ``-b .``.
Internal changes
----------------
* PRoot now relies on Talloc: a hierarchical, reference counted memory
pool system with destructors. It is the core memory allocator used
in Samba: http://talloc.samba.org. This is definitely a worthwhile
dependency for the sake of development scalability and
debuggability. For example, PRoot now has an explicit garbage
collector (c.f. ``tracee->ctx``), and the full dynamic memory
hierarchy can be printed by sending the USR1 signal to PRoot::
native-shell$ proot --mount=$HOME --mount=/proc --rootfs=./slackware-14/
prooted-shell$ kill -s USR1 $(grep Tracer /proc/self/status | cut -f 2)
Tracee 0x6150c0 768 bytes 0 ref' (pid = 22495)
talloc_new: ./tracee/tracee.c:97 0x615420 0 bytes 0 ref'
$exe 0x61bef0 10 bytes 0 ref' ("/bin/bash")
@cmdline 0x61bf60 16 bytes 0 ref' ("/bin/sh", )
/bin/sh 0x61bfd0 8 bytes 0 ref'
$glue 0x61bae0 24 bytes 0 ref' ("/tmp/proot-22494-UfGAPh")
FileSystemNameSpace 0x615480 32 bytes 0 ref'
$cwd 0x61b880 13 bytes 0 ref' ("/home/cedric")
Bindings 0x61b970 16 bytes 0 ref' (host)
Binding 0x615570 8280 bytes 1 ref' (/home/cedric:/home/cedric)
Binding 0x6176a0 8280 bytes 1 ref' (/proc:/proc)
Binding 0x6197d0 8280 bytes 1 ref' (/usr/local/proot/slackware-14:/)
Bindings 0x61b900 16 bytes 0 ref' (guest)
Binding -> 0x6176a0
Binding -> 0x615570
Binding -> 0x6197d0