The first test comes from OpenBSD, and the others are additions or
adaptations.
This is based on OpenBSD's
src/regress/lib/libc/sprintf/sprintf_test.c, v1.3.
I deliberately did not use v1.4 because it's bogus.
semaphores. Specifically, semaphores are now represented as new file
descriptor type that is set to close on exec. This removes the need for
all of the manual process reference counting (and fork, exec, and exit
event handlers) as the normal file descriptor operations handle all of
that for us nicely. It is also suggested as one possible implementation
in the spec and at least one other OS (OS X) uses this approach.
Some bugs that were fixed as a result include:
- References to a named semaphore whose name is removed still work after
the sem_unlink() operation. Prior to this patch, if a semaphore's name
was removed, valid handles from sem_open() would get EINVAL errors from
sem_getvalue(), sem_post(), etc. This fixes that.
- Unnamed semaphores created with sem_init() were not cleaned up when a
process exited or exec'd. They were only cleaned up if the process
did an explicit sem_destroy(). This could result in a leak of semaphore
objects that could never be cleaned up.
- On the other hand, if another process guessed the id (kernel pointer to
'struct ksem' of an unnamed semaphore (created via sem_init)) and had
write access to the semaphore based on UID/GID checks, then that other
process could manipulate the semaphore via sem_destroy(), sem_post(),
sem_wait(), etc.
- As part of the permission check (UID/GID), the umask of the proces
creating the semaphore was not honored. Thus if your umask denied group
read/write access but the explicit mode in the sem_init() call allowed
it, the semaphore would be readable/writable by other users in the
same group, for example. This includes access via the previous bug.
- If the module refused to unload because there were active semaphores,
then it might have deregistered one or more of the semaphore system
calls before it noticed that there was a problem. I'm not sure if
this actually happened as the order that modules are discovered by the
kernel linker depends on how the actual .ko file is linked. One can
make the order deterministic by using a single module with a mod_event
handler that explicitly registers syscalls (and deregisters during
unload after any checks). This also fixes a race where even if the
sem_module unloaded first it would have destroyed locks that the
syscalls might be trying to access if they are still executing when
they are unloaded.
XXX: By the way, deregistering system calls doesn't do any blocking
to drain any threads from the calls.
- Some minor fixes to errno values on error. For example, sem_init()
isn't documented to return ENFILE or EMFILE if we run out of semaphores
the way that sem_open() can. Instead, it should return ENOSPC in that
case.
Other changes:
- Kernel semaphores now use a hash table to manage the namespace of
named semaphores nearly in a similar fashion to the POSIX shared memory
object file descriptors. Kernel semaphores can now also have names
longer than 14 chars (up to MAXPATHLEN) and can include subdirectories
in their pathname.
- The UID/GID permission checks for access to a named semaphore are now
done via vaccess() rather than a home-rolled set of checks.
- Now that kernel semaphores have an associated file object, the various
MAC checks for POSIX semaphores accept both a file credential and an
active credential. There is also a new posixsem_check_stat() since it
is possible to fstat() a semaphore file descriptor.
- A small set of regression tests (using the ksem API directly) is present
in src/tools/regression/posixsem.
Reported by: kris (1)
Tested by: kris
Reviewed by: rwatson (lightly)
MFC after: 1 month
provides the correct semantics for flock(2) style locks which are used by the
lockf(1) command line tool and the pidfile(3) library. It also implements
recovery from server restarts and ensures that dirty cache blocks are written
to the server before obtaining locks (allowing multiple clients to use file
locking to safely share data).
Sponsored by: Isilon Systems
PR: 94256
MFC after: 2 weeks
fifos, as this is required by the Single UNIX Specification, although
not currently implemented on FreeBSD.
While here, fix a bug in the directory timestamp checking test by
sleeping after querying the starting timestamp, rather than before.
AIO calls.
This small program queues up a controllable number of concurrent AIO
read operations w/ controllable io size against a disk or regular file.
There are a few other things to add (notably optional write support!)
but it works well enough at the present time to stress the AIO code out
relatively harshly in the disk IO case.
after similar calls related to struct pwd in libutil/pw_util.c:
- gr_equal()
Perform a deep comparison of two struct grp's. It does a thorough, yet
unoptimized comparison of all the members regardless of order.
- gr_make()
Create a string (see group(5)) from a struct grp.
- gr_dup()
Duplicate a struct grp. Returns a value that is a single contiguous
block of memory.
- gr_scan()
Create a struct grp from a string (as produced by gr_make()).
MFC after: 3 weeks
Solaris and AIX.
fcntl(fd, F_DUP2FD, arg) and dup2(fd, arg) are functionnaly equivalent.
Document it.
Add some regression tests (identical to the dup2(2) regression tests).
PR: 120233
Submitted by: Jukka Ukkonen
Approved by: rwaston (mentor)
MFC after: 1 month
Use the correct value of errno. Although the errno value passed into
printf() follows the *env() call, it is not guaranteed to be the errno
from that call. When I wrote the regression tester, the environment I
used did pass the errno from the call. Consolidate the print for the
return code and errno into a function in the process of fixing this.
Approved by: wes (mentor)
various open flags and then tests various operations to make sure that
they are properly constrained by open flags. Various I/O mechansms
are tried, including aio if compiled into the kernel or loaded as a
module. There's more to be done here but it's a useful start, running
about 220 individual tests.
This is in support of FreeBSD-SA-08:03.sendfile.
the semantics of pthread_mutex_islocked_np() to return true if and only if
the mutex is held by the current thread.
Obviously, change the regression test to match.
MFC after: 2 weeks
- Process (a) is blocked in read on a socket waiting on data.
- Process (b) is blocked in shutdown() on a socket waiting on (a).
- Process (c) delivers a signal to (b) interrupting its wait.
When the signal is delivered, the kernel panics as sblock() fails in
sorflush(). Even if it didn't panic, shutdown() would block potentially
indefinitely waiting for recv() to succeeded. Fixes to follow.
Reported by: Jos Backus <jos at catnook dot com>
mostly just test corner cases rather than accuracy. Some of the
tests don't pass right now if you compile libm at -O2 due to gcc
constant-folding some things that it shouldn't. I'll fix that
shortly.
