it around an application's fork() call. Our new thread libraries
(libthr, libpthread) can now have threads running while another
thread calls fork(). In this case, it is possible for malloc
to be left in an inconsistent state in the child. Our thread
libraries, libpthread in particular, need to use malloc internally
after a fork (in the child).
Reviewed by: davidxu
to be called on first sight of trouble.
"sensitive" is somewhat arbitrarily defined as "setuid, setgid, uid == root
or gid == wheel".
The 'A' option carries no performance penalty.
It is not possible to override this setting: fix the program instead.
Absentmindedly nodded OK to by: various
Also, make an internal _getprogname() that is used only inside
libc. For libc, getprogname(3) is a weak symbol in case a
function of the same name is defined in userland.
If zero bytes are allocated, return pointer to the middle of page-zero
(which is protected) so that the program will crash if it dereferences
this illgotten pointer.
Inspired & Urged by: Theo de Raadt <deraadt@cvs.openbsd.org>
adding (weak definitions to) stubs for some of the pthread
functions. If the threads library is linked in, the real
pthread functions will pulled in.
Use the following convention for system calls wrapped by the
threads library:
__sys_foo - actual system call
_foo - weak definition to __sys_foo
foo - weak definition to __sys_foo
Change all libc uses of system calls wrapped by the threads
library from foo to _foo. In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde). All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes. <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.
Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE. We have recursive mutexes, but would like to avoid
using them if possible.
Remove uneeded includes of <errno.h> from a few files.
Add $FreeBSD$ to a few files in order to pass commitprep.
Approved by: -arch
stderr in case of warnings and errors.
Rename malloc_options to have a leading underscore, I belive I have been
told that is more correct namespace wise.
The recent problems with sshd were due to sshd reassigning
`environ' when setenv() thinks it owns it. setenv() subsequently
realloc()s the new version of environ and *boom*
just use _foo() <-- foo(). In the case of a libpthread that doesn't do
call conversion (such as linuxthreads and our upcoming libpthread), this
is adequate. In the case of libc_r, we still need three names, which are
now _thread_sys_foo() <-- _foo() <-- foo().
Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(),
nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo().
Remove all internal libc usage of: creat(), pause(), sleep(), system(),
tcdrain(), wait(), and waitpid().
Make thread cancellation fully POSIX-compliant.
Suggested by: deischen
points. For library functions, the pattern is __sleep() <--
_libc_sleep() <-- sleep(). The arrows represent weak aliases. For
system calls, the pattern is _read() <-- _libc_read() <-- read().
changes have made this too expensive. This gains about 1.25% on
worldstone on my SMP machine.
Swap-less machines, for instance PicoBSDs, and machines which experience
page-out trafic, check with top(1), will probably want to reenable this
with:
ln -s H /etc/malloc.conf
Suggested by: alc (&dyson ?)
realloc functions check for recursion within the malloc code itself. In
a thread-safe library, the single spinlock ensures that no two threads
go inside the protected code at the same time. The thread implementation
is responsible for ensuring that the spinlock does in fact protect malloc.
There was a window of opportunity in which this was not the case. I'll fix
that with a commit RSN.
Our spinlock implementation allows a particular thread to obtain a lock
multiple times, but release the lock with a single unlock call. Since
we're detecting recursion, we know the lock is already owned by the
current thread in a previous call and must not be released in the
current call. This is really far too dependent on this particular
spinlock implementation, so I've added commented out calls to
THREAD_UNLOCK in the appropriate places. We can activate this code when
spinlock is taught to count each lock operation.
