CVS log for emstar/fusd/libfusd/libfusd.c
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* added more control over device export.
* added a new bit to force export
* added a global flag to set export for all devs for a process, set in misc_init
  by the --enable-remote tag

reject fusd device names that end in '/' or are empty strings

* inc version number to force fusd upgrade
* added helpful error messages

Fixed many memory leaks:

big issues:
1) in sensor_dev.c: i didn't realize that buf_init doesn't free
the buf, just 0s it out (my mistake). This was causing HUGE
memory leaks.
2) Not freeing the data portion of rb_elem_t in ring_buff when
data was aged out!

small ones:
1) emrun_context_t* not freed in emrun_shutdown.
2) issues around devname for opts structs in sensor_dev -
now i dont unnecessarily malloc memory for the name.
3) Set the size for the string_length in parse_cmd in timehist to
be one too big, so this was causing small leaks every time acommand
was parsed.
4) in the enqueue command for timehist, wasn't freeing the command.


Not fixed:
1) buf_init() returns a buf of length = 0, but alloc_size = 1.
So, this one byte is lost if no data is copied into the buffer.
This issue is still not fixed...

Minor problem causing valgrind to complain

* some fixes to the previously-added fusdnet support in libfusd.c
* reorg and first working version of FUSDnet
* FUSDnet is now officially part of the fusdd build

minor fix to libfusd and query_dev_test

* major checkin of fusdnet work.

* fusd API changes
  * fusd_context_t instead of g_event_t
  * added option to disable fusdnet functionality
  * propagated changes throughout libdev etc
  * changes to fusd_msg to support new fusdnet message type

* audio server
  * got rid of stupid rflink junk
  * fixed fusd api change

My attempt at creating a version of FUSD that does not require devfs
and also requires no corresponding userspace daemon.  The kernel module
does the mknod from inside the kernel, calling sys_mknod. Unfortunately,
kernel hackers consider this an evil thing to do, and the sys_* symbols
are no longer exported in later kernels.  So, this code does not work.
But it's nice, so I thought I'd at least check it in for posterity.

Minor fixes to error messages, added todo list..

Lots of changes to fusd!

* NON-DEVFS daemon work:
  * fusdd daemon uses a sorted list to improve lookup performance
  * test code added to fusdd daemon
  * major bug in fusdd fixed: was not unlinking devices
  * fixed a few error cases to be more correct

* changes to kernel module:
  * devfs and non-devfs modes unified for upgrade to 2.6 kernel
    allocates its own device and just uses devfs for doing the mknod
  * "specific waitfor" mode implemented, enables more efficient waiting for
    a specified device
  * single device list and lock broken up into hash table, with
    finer grained locking and separate wait queues for device waitfors

* Modified FUSD to support unlimited numbers of devices in non-devfs mode
* Modified FUSD status protocol to support diffs with a 10-second refresh

FUSD no longer depends on DevFS!!!

TO use this feature, compile on a system with a non-devfs kernel,
insert the module, and run the fusdd user daemon.  Otherwise it
works identically to devfs fusd.

This also involves a change to the fusd status output, so old fusd's
are not compatible with the new fusd.

added the copyright notice to all the source code in the cens repository

- added a copyright notice to all the source code files in the cens
repository

check for errno before calling perror().  Apparently perror can (in some
cases, anyway) corrupt errno because it calls dup().

check for max name len exceeded, AFTER skipping over /dev

fixed a file descriptor leak in fusd_register -- the FUSD control channel
file descriptor was not being closed if registration failed (for certain
failure paths)

Moved /dev/fusd and /dev/fusd_status into a /dev/fusd directory; renamed
/dev/fusd/control and /dev/fusd/status.

/dev/fusd/* now have constants instead of literals in the code.

Added a global process list -- the first step towards being able to
notify processes (such as emrun) that devices are ready for use.

Since we now have a global process list, the kernel module notifies the
library of EEXIST in case of a repeated registration (e.g. registering
a device whose name has already been registered with fusd in the past).
This uses a (potentially slow) linear search for now, but it's something
we only pay on registration, that doesn't happen too often.

Because of the above check, I removed the check from libfusd.c.  That is,
libfusd does not any longer check to see if you are registering a device
that already exists.  This is much faster since it now no longer tickles
devfsd to try to load a kernel module to support your device (something
that really made starting the simulator very slow).  But, it no longer
allows detection of non-devfs devices (e.g., if you try to use FUSD to
register /dev/null, you'll get a confusing EIO and an error in dmesg,
not an EEXIST as would have previously happened.)

Took out the old VERYSAFE debugging mode, since I never use it.

initialize the message to 0 to make valgrind happy

added some debugging to packetdev
* added a new unparse_flags to libfusd
* added a debug status function to packetdev that reports on the
  status of all clients for a packetdev

fixed bug for unsupported ioctl calls

changed errno to 0 on fusd_register success

changed libfusd to do 40 messages at a time instead of 4000

changed param of fusd_register to const char *

fusd_dispatch() no longer has a return value - it simply prints an error
in case something goes wrong.  This makes sense since it is often buried
in functions that make the return value inaccessible anyway, such as
fusd_dispatch_fdset().

Merged FUSD with main branch again

Merged in the new FUSD from the main development branch

Added fusd_destroy, which allows drivers to destroy file state instead
of being forced to return it spuriously (e.g., blocked system calls which
were aborted by the file closing, or poll_diffs that get superceded)

fusd_run no longer complains if a fusd_dispatch returns -EPIPE.

Major changes!!!!!

Restartable system calls have been implemented but this unfortunately
required quite a few changes to the guts of FUSD, which has not been
battle tested yet.  It passes my test suites but this thing needs to be
banged on for a while longer before I'll feel safe with it.

Some highlights of changes:
 -- restartable syscalls implemented
 -- fusd_fops_call() was split into a top half (that generates a message)
    and a bottom half (that waits for the reply).  This makes restartable
    syscalls much easier.
 -- fusd_fops_call_send() -- the top half as described above -- is now
    further decomposed into a function called dev_send_msg which puts a
    message on a device's outgoing message queue.  Used by fusd_fops_reply
    to easily forge a "close" request in response to a successful open
    request that has no connection.
 -- "hints" (i.e. the quick index hint into the fusd_dev's reply array)
    is now part of the fusd_msg instead of being kept internally.  This
    makes the handling of all that state much more scalable since it's
    kept with the request - why didn't I think of this earlier!?!??

Lots of other minor (and some not so minor) things - see diffs for details

fusd_dispatch() no longer has a return value - it simply prints an error
in case something goes wrong.  This makes sense since it is often buried
in functions that make the return value inaccessible anyway, such as
fusd_dispatch_fdset().

Buffers passed to you when clients do writes() are now guaranteed to be
null-terminated.  The 'length' argument has not changed; simply that the
byte following the buffer of size 'length' is now guaranteed to be 0.

Also fixed a missing \n in a debug message.

Did a lot of work in trying to optimize the scheduling of fusd drivers
and the processes using them.

In the kernel: the driver now immediately yields the processor when
it completes a syscall.

In the user-space library: we now try to read as many fusd messages as
possible in fusd_dispatch() before giving up; thanks to the new
yielding in the module, it is very likely (when doing bulk data
transfer) that the app will issue another syscall before the driver's
next read.  This minimizes the number of context switches and syscalls
and increased speed by about 50%.  In particular, bulk data transfers
look (to the driver) like a long series of successful reads; no select
or even blocking on read in between!

We also now (optionally) use wake_up_interruptible_sync instead of plain
wake_up_interruptible in cases when we know we are about to yield to
another process.

fusd_run has been changed to take no args and return no retval; it
simply runs forever doing a fusd_dispatch on any readable FDs.  Meant
to be the simplest of "simple" interfaces.  Changed many example
programs to use the new fusd_run().

Changed kfusd.c default debug level from 10 to 2

Changed __VERYSAFE__ to __FUSD_VERYSAFE__

Better error reporting: library now warns you if you're trying to
register a device which already exists under /dev.

Robustness: we now test our theory that devfs is mounted on /dev before
blindly using it.

Better error reporting so that failures are less confusing

convenience: if the first characters of the name you're trying to
register are SKIP_PREFIX (usually "/dev/"), skip over them.

Added some convenience functions similar to fusd_dispatch, but that
operates on an entire fd_set instead of just a single FD.

added junk to prevent warnings

kernel now passes UID and GID to drivers for their examining pleasure

Added support for modification of the 'offset' by userspace drivers in
read and write system calls.

Changed the userspace library so that it makes a COPY of the file ops
structure, instead of just taking a pointer to it - so that drivers can
register from inside functions without having to worry about the struct
disappearing off the stack

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fixes to make select work correctly

changed sense of FUSD_NOREPLY

this either completely fucked everything up or implemented select

new notify structure..
poll_diff() implemented

changed notify to selected
added callback dispatch for selected and unblock
added accessor inline functions

implemented ioctl for clients

read and write work, whoo hoo!

FIRST VERSION BELIEVED TO HAVE CORRECT LOCKING

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fixed bug in fusd_run()

fixed bug in fusd_run()

new torture test
fixed bugs in fusd_run

mods to fusd_run

added locks for correctness

additional changes for safety

reversed comparison

maybe read works now, god willing

holy shit, does this actually work?

various bug fixes

more care in malloc/free

more care in mem allocation

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some changes to make things compile better

first version of all files