src/lib/libc_r/uthread/uthread_execve.c, branch upstream/11.2.0

Remove libc_r threading library. It has been disconnected from the build

2010-11-13T22:22:18Z

for four years (since r162846). Submitted by: Alexander Best arundel@

Remove 3rd clause, renumber, ok per email

2007-01-12T07:26:21Z

When about to do an execve(), don't reset the O_NONBLOCK flag on any file

2002-11-15T00:34:28Z

descriptors that have the close-on-exec flag set, as that will have no effect anyway and might screw something else up if the file descriptor happens to be shared with another process. PR: standards/43335 MFC after: 1 week

Remove much of the dereferencing of the fd table entries to look

2002-08-29T23:06:07Z

at file flags and replace it with functions that will avoid null pointer checks. MFC to be done by archie ;-) PR: 42100 Reviewed by: archie, robert MFC after: 3 days

To be consistent, use the __weak_reference macro from

2001-04-10T04:19:21Z

instead of #pragma weak to create weak definitions. Suggested by: bde

Add weak definitions for wrapped system calls. In general:

2001-01-24T13:03:38Z

_foo - wrapped system call foo - weak definition to _foo and for cancellation points: _foo - wrapped system call __foo - enter cancellation point, call _foo(), leave cancellation point foo - weak definition to __foo Change use of global _thread_run to call a function to get the currently running thread. Make all pthread_foo functions weak definitions to _pthread_foo, where _pthread_foo is the implementation. This allows an application to provide its own pthread functions. Provide slightly different versions of pthread_mutex_lock and pthread_mutex_init so that we can tell the difference between a libc mutex and an application mutex. Threads holding mutexes internal to libc should never be allowed to exit, call signal handlers, or cancel. Approved by: -arch

Implement zero system call thread switching. Performance of

2000-10-13T22:12:32Z

thread switches should be on par with that under scheduler activations. o Timing is achieved through the use of a fixed interval timer (ITIMER_PROF) to count scheduling ticks instead of retrieving the time-of-day upon every thread switch and calculating elapsed real time. o Polling for I/O readiness is performed once for each scheduling tick instead of every thread switch. o The non-signal saving/restoring versions of setjmp/longjmp are used to save and restore thread contexts. This may allow the removal of _THREAD_SAFE macros from setjmp() and longjmp() - needs more investigation. Change signal handling so that signals are handled in the context of the thread that is receiving the signal. When signals are dispatched to a thread, a special signal handling frame is created on top of the target threads stack. The frame contains the threads saved state information and a new context in which the thread can run. The applications signal handler is invoked through a wrapper routine that knows how to restore the threads saved state and unwind to previous frames. Fix interruption of threads due to signals. Some states were being improperly interrupted while other states were not being interrupted. This should fix several PRs. Signal handlers, which are invoked as a result of a process signal (not by pthread_kill()), are now called with the code (or siginfo_t if SA_SIGINFO was set in sa_flags) and sigcontext_t as received from the process signal handler. Modify the search for a thread to which a signal is delivered. The search algorithm is now: o First thread found in sigwait() with signal in wait mask. o First thread found sigsuspend()'d on the signal. o Current thread if signal is unmasked. o First thread found with signal unmasked. Collapse machine dependent support into macros defined in pthread_private.h. These should probably eventually be moved into separate MD files. Change the range of settable priorities to be compliant with POSIX (0-31). The threads library uses higher priorities internally for real-time threads (not yet implemented) and threads executing signal handlers. Real-time threads and threads running signal handlers add 64 and 32, respectively, to a threads base priority. Some other small changes and cleanups. PR: 17757 18559 21943 Reviewed by: jasone

Use __strong_reference() instead of __weak_reference() to assure that the

2000-01-29T22:53:55Z

weak symbols of the same name are not used.

Simplify sytem call renaming. Instead of _foo() <-- _libc_foo <-- foo(),

2000-01-27T23:07:25Z

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

Track libc's three-tier symbol naming. libc_r must currently implement

2000-01-12T09:28:58Z

the _libc_*() entry points and add *() weak aliases. This will all change for the better when libc_r becomes libpthread.