add linux_emul base, reorganize docs

[openbsd_emul.git] / linux_emul_base / CHANGES

2008-08-16
Creation of a CHANGES file

A entry starts with the date followed by a newline and then
the content follows. Usualy, the first line after the date
is some short description and then a loger follows.
To terminate the entry, intert two newlines at the end.

So this entry serves as an exampe. Hope this is simple enougth :-)


2008-08-16
New debugging implemented

Debug code removed from mem.c and trap.c and rewrote in
acid. See the DEBUGGING section in the HOWTO file for further
information.


2008-08-17
Fontconfig crash fixed, Debug code fixes

libfontconfig mapped some config files with len == 0, this
was not handled correctly so it crashed.

the umem() acid function didnt check for zero segment
pointers so it showd invalid data for the mostly unused
SEGSHARED segment.


2008-08-18
Some minjor fixes

more checking in memory manager
sys_[gs]etpgrp implemented for pid != current->pid
renamed emu.c to main.c
set UID/GID/EUID/EGID in AUXVEC on exec()



2008-08-21
Making prof(1) work (at least dont let it crash)

mem.c: convertseg():

Peplaced read() calls to pread() to prevent profiling related crash.
The problem was that convertseg() detaches the DATA segment reattaches
a new one and used read() to get the contents back.  read() was a
profiled function and the profiler finds its structures cleared to
zero and crashes.  We now use pread() that is a unprofiled assembly
syscall stub.

Still, child processes and kprocs are not currently profiled.


2008-08-22
AF_UNIX client sockets implemented

Its a little bit of a hack. We do the AF_UNIX handling like APE
does so we can interact with the ported Xservers Xbr and equis.


2008-08-23
Work arround for mozilla GPFAULT bug

If a process is notified that he has pending signals with the
"sig" message and if the note interrupts the execution of a
INT 0x80 instruction, a syscall in the handler causes mystic
crashes i dont understand.

The work arround detects the condition and delays the
handling of the signals returning back to userspace.

I could reproduce the condition and this hack seems
to work. I should write some testcase to analyze this
condition further. Maybe its some kernel bug.


2008-08-23
Minjor file related fixes/cleanups

- Implemented in miscdev.c for writable /dev/zero
- sys_umask() now returns the previous umask
- default umask set to 022
- sys_umask() sys_cwd() moved from proc.c to file.c


2008-08-24
linuxemu.rc script updated

- resolve relative rootpath
- generate /etc files for hostname and resolv.conf if not readable
- removed enviroment user->USER home->HOME conversion in main.c


2008-09-10
Better work arround for mozilla GPFAULT bug

The problem arises because of the handling of notes in Plan9 kernel.

It happens if linux code does a syscall while here are usernotes (like
the "sig" ones) queued in the process note[] array.  Then the trap()
function in the kernel will enqueue the trap in the queue and the user
note gets handled first.

Now, after we have done a syscall in the note handler of the user
signal, notify() gets called in the kernel that detects the next note
to be a trap and thinks the note handler itself caused it and kills
the process.

I suggested a patch that makes sure traps get enqued on the head of
the note[] array so that they get handled before a user note but its
not decided to be applied yet so here is the work arround.

The work arround avoids posting notes to a process that could possibly
cause a trap in the future before the usernote gets handled.  (this
excluded all linux code because it can issure a syscall anytime) The
only time it is save to post notes is if we are in linuxemu syscall
handler.

This is mostly the case anyway when notes are used to interrupt
blocking syscalls (waking a process sleeping in a sigsuspend for
example)

Linuxcode that would spin in a endless loop will not be interrupted by
notes/signals anymore.


2008-09-20
Minjor stuff

Masking more fp-errors in trap.c. (To get some dos game running in
bochs)

prboom and zsnes was bumpy sometimes because our select() didnt set
the struct timeval *tvp to the time the select call did not slept.

I stat function pointer was removed from the Ufile struct and all the *dev.c
files. I have no need to return custom stats from the devices right now
(except for /dev/zero (mode & 0222)) so i move the only case where its
needed into the hackish dir2statmode function in p9dev.c. Here is also
an fd field added to the generic Ufile scruct because most of all devices
use plan9 filedescriptors at some point and we use it in fstat(). Saves some
casting and fstat can use the fd (when its available) to make a dirstat() and
convert to linux format.

For the postnote stuff mentiond in the last changes entry, here is a global
flag in main.c (notehack = 1) to enable/disable the work arround.


2008-09-21
atime/mtime, AT_CLKTCK

new syscalls
- sys_utime
- sys_utimes
- sys_times

the AT_CLKTCK entry in exec is set to _tos->cyclefreq
now.


2008-10-05
faster death proc detection

Using linuxemu from terminal caused huge network load
because we did a lookup of /proc/# on every timer round.

now we keep open filedescriptors for /proc/#/args and
/proc/#/note in the proc structure and only check for
dead procs every second.


2008-10-05
sound (/dev/dsp)

OSS sound implemented, its only tested with some SDL
apps (zsnes, prboom).

The output frequency is hardcoded at 44100 Hz and 2
channels stereo at the moment.


2008-10-20
dsp, stat, mkfile, -d, dns, fs

dspdev detects output frequency now and implement more
ioctls.

here is an universal Ustat and Udirent structs to separate
the linux formats from driver code.

big chnage in all devices, added indirection layer fs.c that
has some kind of mapping from path -> device and forwards
filesystem calls to device drivers. now drivers can return
correct stat information.

this is needed for implementing /dev/pts later.

removed the /etc/(hosts resolve.conf) generation code from
linuxemu.rc because they dont work in some cases and
cause maintence nightmares.

use the -d switch for turning on trace to stderr. so we dont
need to always change the if(0) from trace.c and recompile.

force compiler flags in mkfile, the -T from new mkone breaks
build on current distribution.


2008-10-27
lots of fixes

- off by one error basepath()
- chmod used access which resolves always to link target
- runlink
- the note hack broke sigprocmask, and sometimes failed
   to interrupt a sleepproc(). this is now handled in
   interruptproc(). (this makes drawterm work on linuxemu)
- write() to pty was not synchronized/not blocking that
   caused some apps to spin in write() or others to drop
   characters (curses).


2008-10-28
grow filedescriptor table in dup2

- if the new fd supplied is out if range, dont return error but
   grow the fdtab so it fits in. (this make configure work)

2008-11-15
lots of changes

- Updated HOWTO

- included <ureg.h> in some modules. this fixed the type
   signature errors of 8l when compiling with -T flag.

- fixed bug in exec()
   exec needs to run outside the the note context, because it
   is deleting memory segments and that can cause the removal
   of the stack segment as well. we have to set current->syscall
   to nil to avoid getting a note posted that could interrupt us in
   the middle of some malloc() or something.

- sys_pipe() FD_CLOEXEC
   sys_pipe() create the filedescriptors with FD_CLOEXEC bit
   set as open() does. this is wrong and caused gimp plugins
   to fail.

- new signal handling code
   signal.c has changed a bit. now CLONE_THREAD procs
   share a signal queue and proc() uses wantsignal() to
   figure out what process to interrupt.

- restartable syscalls
   re process SA_RESTART flag now and are able to restart syscalls
   that got interrupted by such signals. sleepproc() returns -ERESTART
   by default now. sys_poll() and sys_sleep() will return -EINTR in
   any case.

- fs reorganized, [sg]etxattr added, p9cwd added as an optimization
   to avoid walks().

- ptydev emits SIGINTR to process group, added tty to Uproc.

- added fddev (/dev/fd)

- exitproc() now emits SIGCHLD.

- mem.c: addrok() now takes a prot flags parameter so we can test
   for expected memory protection too.

- profme(): profiling support for child processes added

- initialization completly moved in main()

- fchmod, fchown, ftruncate moved to file.c


2008-10-19
just code dressing...

renamed some files, added typedef for Ureg, abstracted syscall specific
code in linuxcall.c, more tracing...


2009-02-06
Fixed the opera fork() no more threads bug

There was a problem of dns resolver zombie processes created by
operseemed that used up all the process table due to incomplete
implementation of clone().  Linux specified a exit signal in the lower
byte of the clone- flags parameter to tell if the process should hang
arround as zombie so that the parent can wait for it.  If no signal is
specified here, then the process should exit without becoming a
zombie.  Here is also the case that the parent ignores the SIGCHLD
signal or has SA_NOCHLDWAIT flags on the SIGCHLD set.  In that case
the child should also purge itself.  I implemented reparenting,
because i suspected the bug there but this was not the case.

Here is a new uprocs() acid function that dumps the proctab.


2009-02-18
Minjor changes

Added anonymous area merging to reduce the area count and removed
redundant clearmem calls. Changed Uwaitq lock from QLock to normal
spinlock. Removed some trace() calls.

The biggest change is that linuxemu.rc now is able to start equis. This
simplyfies writing wrapper scripts to start a browser or other X11 apps.


2009-03-25
Simplyfied area merging in memory manager

Areas are doubly linked now so its easier to get the previous area for
mergearea().


2009-03-30
Fixed man-bug. (Restarting syscalls)

Restarting syscalls failed if the singal that was send to the interrupted
process was blocked. This is fixed now.


2009-04-01
fixed awd-bug (use builtin cd), make errors more verbose in exec.c

bla

2009-05-11
fix pipeseek, added pread64, pwrite64 syscalls.

forgot to return -ESPIPE on seekpipe.
implemented pread64/pwrite64 (needed by git).


2009-07-25
random stuff

- incred bufproc read and queuesize to 4K/64K (fixes links2 -g hang)
- reuse buffers in bufproc
- cleanup timer stuff, introduce 5ms min sleep time, avoid interrupt note
- fix sys_select() to always modify tv
- fix format mismatch in nextsignal
- dont combine in sys_readv/sys_writev
- fix open in devdsp.c
- s/memcpy/memmove/g
- dont reset segment registers for signal handlers
- possibly more that i forgot... use history(1)


2009-07-27
fixed audio delay

keeping track of how many samples (time) has been submitted
to /dev/audio already and wait when the buffer grows over some
treshold. this removes the audio delay from games :)


2009-07-29
doc

put documentation in doc subdirectory.


2009-07-31
mremap, segbrk shrinking, pagesize, doc

rewrote mremap implementation to correctly clear area for shrinking.
handles more error cases and checks for overlap. this fixes the gimp
invalid pointer bug.

removed segment shrinking with segbrk as this feature may be removed
in newer kernel versions as it introduced a bug where it is possible to
unmap pages while the kernel touches them and cause a panic.

removed the ROUNDPAGE() macro from dat.h. heres a pagealign()
function in mem.c now and the global variable pagesize that is initialized
in main.

some documentation cleanups.


2009-08-24
dspdev improvements.

do some linear interpolation in audio resampling to get better sound quality.
avoid copy when no resampling is required.  reflect queue full in
GETOSPACE ioctl. cleanup code to avoid vlong calculations.


2009-08-26
bugs

fixed uninitialized values in stat wich caused -EOVERFLOW on linux
kernel build.  removed wakeableproc() (changes in signal.c, ptydev.c,
bufproc.c, poll.c).  fixed sigsuspend race.  simpler waitq code (uses
lesser memory too).  fixed waitpid race.  added /dev/dsp0 to dspdev
(makes mikmod work).  fixed rfork/notify crash.


2009-08-30
mplayer, bb, audacity play cursor, bugs

refactored timers, alarm and deadproccheck into one timerproc and
removed timer.c. every Uproc has a timeout field now that is the
time in nanoseconds when the timeout expires. on expiration, the
timerproc sets the value to zero and does a wakeup on the
timed out process. a process sets/resets its timeout with
settimeout(delta). the remaining time in ms can be queried with
timeoutremain().

fixed missing protection flags in setupstack.

more acurate GETOSPACE (mplayer, bb) and new GETOPTR
ioctl (needed for audacity play cursor) in dspdev.c.

handle kill note as SIGKILL in trap.c.

handle illegal instruction as SIGILL as pass/restore sigcontext
(needed for mplayer runtime SSE check).

sys_sigreturn now uses current->ureg->sp to find the restore
information.

preallocate all Uprocs.


2009-09-06
cleanup

removed dev argument from fdgetfile()

return correct -ENOSOCK in socketcall()

fixed pread/pwrite, dev->read/dev-write now take a offset
argument.

fixed time diff overflow in dspdev


2009-09-08
fuckup, O_TRUNC, restaring syscalls, rc, getdents

fucked up:
- seek didnt work for whence == 1 as the plan9 seek pointer was
   never moved in read due to change to pread. this caused cp to
   corrupt the output file when it skipped null blocks.
- basepath in fs.c was broken
- readv/writev didnt increment the file offset

what we have now is that file.c does all the offset tracking, and
devices provide a size() function that returns the actual file size.

added O_TRUNC for open.

signal restarting sometimes resulted in returning -ERESTART to
userspace. this could happen when another thread had stolen
our signal. we now restart the syscall in nextsignal() even if
here was no signal pending for us.

removed the exitsig function from linuxemu.rc as we can use
the -terminate option of the xserver to get it shutdown.

read the whole directory, then calculate file offset for directory
entries. 


2009-09-12
signal handling changes, acid, rc


2009-09-20
sockets, basepath, alarm

fixed error in basepath (*ps vs ps) and implemented nonblocking connect,
server sockets, socketpair, sys_alarm


2009-10-13
lots of changes

simplified locking by making process wakeup non blocking.
to not miss wakeups, the to be suspended proc should call wakeme(1)
before it goes to sleep.

timers for alarm/itimer have been moved to the per "process" signal
data. current->timeout is still local to the current "thread".

sys_kill() now makes sure we only send one signal per "process".

syscall restarting now can use the Urestart (current->restart)
structure to remember state.  (implemented for nanosleep, poll and
select)

changed default to non tracing.

pty now handles winsize changes. fixing current tty changing. (ssh bug,
rxvt bug)

added /dev/random and /dev/urandom to miscdev.

more ioctls for dspdev.

enforce non reentancy for traps.


2009-10-15
fixed sys_brk()

we now use a separate segment for the BSS and dont intermix mmap and brk.
thanks jibanes for reporting!


2010-02-27
futex, TLS, mprotect

implemented sys_futex() finally

changed tls to use the new /dev/gdt interface to change its
process segment descriptors

fixed mprotect


20010-04-30
linuxemu.rc gone, documentation

removed linuxemu.rc and replaced it with linux.

usage: linux [-h] [-d...] [-u uid] [-g gid] [-startx] [-display :n] [-e emubin] [-r linuxroot] command [args ...]

linuxroot is now an optional parameter (-r). it will default to /sys/lib/linux.

dont hide /lib/tls anymore and bind devarch. if you dont want to
patch your kernel with the segdescr patch and use mroot[-linuxemu].tbz
you can rename /lib/tls to /lib/_tls_disabled_.


2010-05-02
exit_group, exec, futex, waitpid, quoted arguments

properly implement exit_group and zap all threads. notify
all parent threads.

zap threads in exec.

implement FUTEX_REQUEUE and FUTEX_CMP_REQUEUE.

handle WALL, WCLONE and WNOHANG in waitpid.

preserve quoted arguments to linux.


2010-05-11
select/poll and EBADF, execve malloc, set_thread_area, initproc, SIGSTOP/SIGCONT, 
tty, getsid, getpeeraddr, /proc

select and poll never return -EBADF but ignore the offending
filedescriptor. this is wrong in the manpage! (this was needed
to survive the python configure script)

handle malloc errors in execve and dont panic when elf
loading fails but kill the process.

detect empty descriptors in set_thread_area so descriptors
can be freed.

move some of the initialization from main to initproc.

SIGSTOP/SIGCONT handling now works for thread groups. for this
we now have stopproc() and contproc() that are called from the
signal code when SIGSTOP or SIGCONT signal is received. each Uproc
now has a traceproc callback that is called when we enter or
exit the kernel. zapthreads() and stopproc() use this to get all threads
in the wanted state. for stopped procs, waiting happens in
the signal code so calling handlesignals() of a stopped proc will
block until it gets killed or continued.

new fields in Uproc:
traceproc, tracearg - called when entering or exiting the kernel
wstate - current wait state of this process. WEXITED, WSTOPPED, WCONTINUED.
wevent - like wstate, but reset by waitpid
comm - double null terminated string array. first entry is the full exe name
followd by the exeve arguments.

heres a new format %S for signal numbers.

the per thread tty is gone. the tty is now in the per process signal queue.
gettty() and settty() can be used to modify it. ptydev now allows opening
the slave tty multiple times. (fixes midnight commander error)

implemented sys_getsid().

fix AF_INET padding and byte order for getpeername socketcall.

implemented /proc (procdev). fddev is gone. /dev/tty handled by
ptydev now. this makes pkill, ps, top and inkscape work!


2010-05-28
fixed pipe filedescriptor leak in AF_UNIX

we leaked the sock->other descriptor when failing to connect
a AF_UNIX socket. thanks yarikos for reporting!


2011-08-05
rename to existing symlink target bug, profine -> profile

renaming a symlink to a existing symlink would cause the
file file to be renamed to .udir.L.udir.L....

fix profine/profile typo

2014-11-20
change uname release to 3.2.1 to make debian 7.0 not complain
(thanks henesy)