that counted the number of elements in argv. The counter is incremented
in the next-iteration section of the loop, not the body, so at termination
it's already "counted" the element that failed the continuation test - in
this case the NULL argv terminator.
Noted by: bde
call them. All the execX() libc functions should be vfork() safe now.
Specifically:
- execlp() does the argument count-and-build into a vector from alloca
(like the others) - buildargv() is no longer used (and gone).
- execvp() uses alloca/strcpy rather than strdup().
- the ENOEXEC handler uses alloca rather than malloc.
- a couple of free() calls removed - alloca works on the local stack and
the allocations are freed on function exit (which is why buildargv
wasn't useful - it's alloca() context would disappear on return).
Along the way:
- If alloca() fails (can it?), set errno = ENOMEM explicitly.
- The ENOEXEC recovery routine that trys again with /bin/sh appeared to
not be terminating the new argv[] array for /bin/sh, allowing it to
walk off the end of the list.
I dithered a bit about using alloca() even more as it's most commonly
associated with gcc. However, standalone portable (using malloc) and
machine-specific assembler alloca implementations appear to be available
on just about all the architectures we're likely to want to port to.
alloca will be the least of our problems if ever going to another compiler.
kern.chroot_allow_open_directories = 0
chroot(2) fails if there are open directories.
kern.chroot_allow_open_directories = 1 (default)
chroot(2) fails if there are open directories and the process
is subject of a previous chroot(2).
kern.chroot_allow_open_directories = anything else
filedescriptors are not checked. (old behaviour).
I'm very interested in reports about software which breaks when
running with the default setting.
affects cases where there is a slave but no master. These bugs
were usually recovered from provided ATAPI was configured, but only
after lengthy delays. Configuring ATAPI still fixes some bugs for
non-atapi drives.
Don't wait for seek complete in wdreset(). If necessary for pre-ata
drives, it can be waited for later (we got it wrong by only looking
at it for drive 0 anyway). It is set as part of a historical
signature for ata drives but doesn't say anything useful about the
reset state. It is cleared as part of a non-historical signature
for atapi drives so that drivers which don't understand atapi drives
seem to see no drive. Waiting for it caused lengthy delays and
broke the status returned by wdreset() in cases where the master
was not an ata drive. Then the whole wdprobe() failed in some
cases where the recovery code didn't work.
Don't wait for drive ready in wdreset(). The considerations are
the same as for seek complete, except drive ready does say something
useful about the reset state of ata drives, and waiting for it
later is required anyway for such drives.
Lengthy delays can now be avoided by not configuring nonexistent
(ata) drives. Unfortunately, this breaks detection of atapi drives
in some configurations.
Recognize aic7895 controllers that have been "acquired" by a RAIDPort
card as normal aic7895s.
Recognize the aic7815 Raid Parity/Memory controller chip and notify
the user that it's RAID functionality will be ignored.
Don't mess with the IRQMS bit in the host control register unless
we are an aic7770 chip.
Use calling context to determine if the card is already paused when
we update the target message request bit field in controller scratch
ram. Looking at the paused bit in the HCNTRL register opened up a
race condition.
Insert delays in the target message request update routine as a temporary
work around for what looks like a chip bug. I'm still investigating this
one.
Fix the Abort/Abort Tag/BDR handler to pull its message from the message
buffer in our softc instead of attempting to get it from a register on
the controller. The message is never recorded by the controller in the
new message scheme.
Don't rely on having an SCB when a BDR occurs. We can issue these during
invalid reconnects to.
Fix a few cases where we were restarting the sequencer but then still
falling out of a switch statement to unpause the sequencer again.
This could cause us to mess up sequencer state if it generated another
pausing interrupt between the time of the restart and unpause.
Kill the 'transceiver settle' loop during card initialization. I
failed to realize that a controller that is not connected to any
cables will never settle or enable the SCSI transceivers at all.
The correct solution is to monitor the IOERR interrupt which indicates
that the transceiver state has changed (UW<->LVD).
Modify the aic7xxx assembler to properly echo input when stdin is not
a tty.
implementation requires two things:
1.) The priority queues must be protected during insertion
and removal of threads. Since the kernel scheduler
must modify the priority queues, a spinlock for
protection cannot be used. The functions
_thread_kern_sched_defer() and _thread_kern_sched_undefer()
were added to {un}defer kernel scheduler activation.
2.) A thread (active) priority change can be performed only
when the thread is removed from the priority queue. The
implementation uses a threads active priority when
inserting it into the queue.
A by-product is that thread switches are much faster. A
separate queue is used for waiting and/or blocked threads,
and it is searched at most 2 times in the kernel scheduler
when there are active threads. It should be possible to
reduce this to once by combining polling of threads waiting
on I/O with the loop that looks for timed out threads and
the minimum timeout value.
o Functions to defer kernel scheduler activation were added. These
are _thread_kern_sched_defer() and _thread_kern_sched_undefer()
and may be called recursively. These routines do not block the
scheduling signal, but latch its occurrence. The signal handler
will not call the kernel scheduler when the running thread has
deferred scheduling, but it will be called when running thread
undefers scheduling.
o Added support for _POSIX_THREAD_PRIORITY_SCHEDULING. All the
POSIX routines required by this should now be implemented.
One note, SCHED_OTHER, SCHED_FIFO, and SCHED_RR are required
to be defined by including pthread.h. These defines are currently
in sched.h. I modified pthread.h to include sched.h but don't
know if this is the proper thing to do.
o Added support for priority protection and inheritence mutexes.
This allows definition of _POSIX_THREAD_PRIO_PROTECT and
_POSIX_THREAD_PRIO_INHERIT.
o Added additional error checks required by POSIX for mutexes and
condition variables.
o Provided a wrapper for sigpending which is marked as a hidden
syscall.
o Added a non-portable function as a debugging aid to allow an
application to monitor thread context switches. An application
can install a routine that gets called everytime a thread
(explicitly created by the application) gets context switched.
The routine gets passed the pthread IDs of the threads that are
being switched in and out. I found this useful, but we can
get rid of it if you want.
Submitted by: Dan Eischen <eischen@vigrid.com>
o Runnable threads are now maintained in priority queues. The
implementation requires two things:
1.) The priority queues must be protected during insertion
and removal of threads. Since the kernel scheduler
must modify the priority queues, a spinlock for
protection cannot be used. The functions
_thread_kern_sched_defer() and _thread_kern_sched_undefer()
were added to {un}defer kernel scheduler activation.
2.) A thread (active) priority change can be performed only
when the thread is removed from the priority queue. The
implementation uses a threads active priority when
inserting it into the queue.
A by-product is that thread switches are much faster. A
separate queue is used for waiting and/or blocked threads,
and it is searched at most 2 times in the kernel scheduler
when there are active threads. It should be possible to
reduce this to once by combining polling of threads waiting
on I/O with the loop that looks for timed out threads and
the minimum timeout value.
o Functions to defer kernel scheduler activation were added. These
are _thread_kern_sched_defer() and _thread_kern_sched_undefer()
and may be called recursively. These routines do not block the
scheduling signal, but latch its occurrence. The signal handler
will not call the kernel scheduler when the running thread has
deferred scheduling, but it will be called when running thread
undefers scheduling.
o Added support for _POSIX_THREAD_PRIORITY_SCHEDULING. All the
POSIX routines required by this should now be implemented.
One note, SCHED_OTHER, SCHED_FIFO, and SCHED_RR are required
to be defined by including pthread.h. These defines are currently
in sched.h. I modified pthread.h to include sched.h but don't
know if this is the proper thing to do.
o Added support for priority protection and inheritence mutexes.
This allows definition of _POSIX_THREAD_PRIO_PROTECT and
_POSIX_THREAD_PRIO_INHERIT.
o Added additional error checks required by POSIX for mutexes and
condition variables.
o Provided a wrapper for sigpending which is marked as a hidden
syscall.
o Added a non-portable function as a debugging aid to allow an
application to monitor thread context switches. An application
can install a routine that gets called everytime a thread
(explicitly created by the application) gets context switched.
The routine gets passed the pthread IDs of the threads that are
being switched in and out.
Submitted by: Dan Eischen <eischen@vigrid.com>
Changes by me:
o Added a PS_SPINBLOCK state to deal with the priority inversion
problem most often (I think) seen by threads calling malloc/free/realloc.
o Dispatch signals to the running thread directly rather than at a
context switch to avoid the situation where the switch never occurs.
