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* major improvements to cancellation handlingRich Felker2011-03-292-6/+13
| | | | | | | | | | | | | - there is no longer any risk of spoofing cancellation requests, since the cancel flag is set in pthread_cancel rather than in the signal handler. - cancellation signal is no longer unblocked when running the cancellation handlers. instead, pthread_create will cause any new threads created from a cancellation handler to unblock their own cancellation signal. - various tweaks in preparation for POSIX timer support.
* revert some more spin optimizations that turned out to be pessimizationsRich Felker2011-03-282-3/+2
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* fix broken spinlock due to miscompilationRich Felker2011-03-281-1/+1
| | | | actually this trick also seems to have made the uncontended case slower.
* match glibc/lsb cancellation abi on i386Rich Felker2011-03-256-0/+36
| | | | | | | | glibc made the ridiculous choice to use pass-by-register calling convention for these functions, which is impossible to duplicate directly on non-gcc compilers. instead, we use ugly asm to wrap and convert the calling convention. presumably this works with every compiler anyone could potentially want to use.
* prepare pthread_spin_unlock for archs that need memory barriersRich Felker2011-03-241-1/+2
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* optimize contended case for pthread_spin_trylockRich Felker2011-03-241-1/+2
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* optimize spinlock spinRich Felker2011-03-241-1/+1
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* overhaul cancellation to fix resource leaks and dangerous behavior with signalsRich Felker2011-03-243-10/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | this commit addresses two issues: 1. a race condition, whereby a cancellation request occurring after a syscall returned from kernelspace but before the subsequent CANCELPT_END would cause cancellable resource-allocating syscalls (like open) to leak resources. 2. signal handlers invoked while the thread was blocked at a cancellation point behaved as if asynchronous cancellation mode wer in effect, resulting in potentially dangerous state corruption if a cancellation request occurs. the glibc/nptl implementation of threads shares both of these issues. with this commit, both are fixed. however, cancellation points encountered in a signal handler will not be acted upon if the signal was received while the thread was already at a cancellation point. they will of course be acted upon after the signal handler returns, so in real-world usage where signal handlers quickly return, it should not be a problem. it's possible to solve this problem too by having sigaction() wrap all signal handlers with a function that uses a pthread_cleanup handler to catch cancellation, patch up the saved context, and return into the cancellable function that will catch and act upon the cancellation. however that would be a lot of complexity for minimal if any benefit...
* global cleanup to use the new syscall interfaceRich Felker2011-03-204-6/+5
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* if returning errno value directly from a syscall, we need to negate it.Rich Felker2011-03-192-2/+2
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* syscall overhaul part two - unify public and internal syscall interfaceRich Felker2011-03-197-15/+9
| | | | | | | | | | | | | | | | with this patch, the syscallN() functions are no longer needed; a variadic syscall() macro allows syscalls with anywhere from 0 to 6 arguments to be made with a single macro name. also, manually casting each non-integer argument with (long) is no longer necessary; the casts are hidden in the macros. some source files which depended on being able to define the old macro SYSCALL_RETURNS_ERRNO have been modified to directly use __syscall() instead of syscall(). references to SYSCALL_SIGSET_SIZE and SYSCALL_LL have also been changed. x86_64 has not been tested, and may need a follow-up commit to fix any minor bugs/oversights.
* overhaul syscall interfaceRich Felker2011-03-191-2/+2
| | | | | | | | | | | | | | | this commit shuffles around the location of syscall definitions so that we can make a syscall() library function with both SYS_* and __NR_* style syscall names available to user applications, provides the syscall() library function, and optimizes the code that performs the actual inline syscalls in the library itself. previously on i386 when built as PIC (shared library), syscalls were incurring bus lock (lock prefix) overhead at entry and exit, due to the way the ebx register was being loaded (xchg instruction with a memory operand). now the xchg takes place between two registers. further cleanup to arch/$(ARCH)/syscall.h is planned.
* implement robust mutexesRich Felker2011-03-178-10/+78
| | | | | | some of this code should be cleaned up, e.g. using macros for some of the bit flags, masks, etc. nonetheless, the code is believed to be working and correct at this point.
* avoid function call to pthread_self in mutex unlockRich Felker2011-03-171-1/+1
| | | | | | if the mutex was previously locked, we can assume pthread_self was already called at the time of locking, and thus that the thread pointer is initialized.
* unify lock and owner fields of mutex structureRich Felker2011-03-173-7/+6
| | | | | | this change is necessary to free up one slot in the mutex structure so that we can use doubly-linked lists in the implementation of robust mutexes.
* optimize contended normal mutex case; add int compare-and-swap atomicRich Felker2011-03-171-1/+1
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* simplify logic, slightly optimize contended case for non-default mutex typesRich Felker2011-03-161-4/+2
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* correct error returns for error-checking mutexesRich Felker2011-03-162-2/+6
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* cut out a syscall on thread creation in the case where guard size is 0Rich Felker2011-03-161-1/+1
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* don't expose EAGAIN, etc. from timed futex wait to callerRich Felker2011-03-161-1/+4
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* implement flockfile api, rework stdio lockingRich Felker2011-03-121-0/+1
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* implement dummy pthread_attr_[gs]etschedparam functionsRich Felker2011-03-112-0/+14
| | | | | | | | for some reason these functions are not shaded by the PS/TPS option in POSIX, so presumably they are mandatory, even though the functionality they offer is optional. for now, provide them in case any programs depend on their existence, but disallow any priority except the default.
* fix pthread_attr_* implementations to match corrected prototypesRich Felker2011-03-114-4/+4
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* fix failure behavior of sem_open when sem does not existRich Felker2011-03-101-1/+5
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* fix some semaphore wait semantics (race condition deadlock and error checking)Rich Felker2011-03-102-1/+7
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* fix sem_open and sem_close to obey posix semanticsRich Felker2011-03-102-33/+80
| | | | | | | | | multiple opens of the same named semaphore must return the same pointer, and only the last close can unmap it. thus the ugly global state keeping track of mappings. the maximum number of distinct named semaphores that can be opened is limited sufficiently small that the linear searches take trivial time, especially compared to the syscall overhead of these functions.
* optimize pthread termination in the non-detached caseRich Felker2011-03-101-4/+15
| | | | | | | we can avoid blocking signals by simply using a flag to mark that the thread has exited and prevent it from getting counted in the rsyscall signal-pingpong. this restores the original pthread create/join throughput from before the sigprocmask call was added.
* security fix: check that cancel/rsyscall signal was sent by the process itselfRich Felker2011-03-101-0/+3
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* fix error handling for pthread_sigmaskRich Felker2011-03-091-0/+10
| | | | it must return errno, not -1, and should reject invalud values for how.
* optimize pthread initializationRich Felker2011-03-091-2/+2
| | | | | | the set_tid_address returns the tid (which is also the pid when called from the initial thread) so there is no need to make a separate syscall to get pid/tid.
* simplify and optimize pthread_mutex_trylockRich Felker2011-03-081-17/+16
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* rwlock trylock functions were wrongly returning EAGAIN instead of EBUSYRich Felker2011-03-082-3/+3
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* fix major breakage in pthread_once (it was always deadlocking)Rich Felker2011-03-081-8/+7
| | | | | | the issue was a break statement that was breaking only from the switch, not the enclosing for loop, and a failure to set the final success state.
* fix and optimize non-default-type mutex behaviorRich Felker2011-03-083-25/+18
| | | | | | | | | problem 1: mutex type from the attribute was being ignored by pthread_mutex_init, so recursive/errorchecking mutexes were never being used at all. problem 2: ownership of recursive mutexes was not being enforced at unlock time.
* implement pthread_mutexattr_[gs]etpshared functionsRich Felker2011-03-082-0/+16
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* disallow cpu time clocks as condattr clock valuesRich Felker2011-03-081-1/+1
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* fix off-by-one error in sem_(timed)wait (using old sem value instead of new)Rich Felker2011-03-071-1/+1
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* use the selected clock from the condattr for pthread_cond_timedwaitRich Felker2011-03-072-1/+2
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* implement pthread_rwlockattr_* (essentially no-ops)Rich Felker2011-03-074-0/+28
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* implement pthread_condattr_* interfacesRich Felker2011-03-076-0/+45
| | | | | note that, while the attributes are stored, they are not used in pthread_cond_init yet.
* reject invalid attribute settingsRich Felker2011-03-072-0/+2
| | | | | note that this is a pedantic conformance issue and waste of code. it only affects broken code or code that is probing for conformance.
* implement barrier attribute functions (essentially no-ops)Rich Felker2011-03-074-0/+27
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* enforce stack size min in pthread_attr_setstacksizeRich Felker2011-03-041-1/+1
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* implement POSIX semaphoresRich Felker2011-03-0410-0/+201
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* optimize POSIX TSD for fast pthread_getspecificRich Felker2011-03-034-9/+14
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* use rt_sigprocmask, not legacy sigprocmask, syscall in pthread exit codeRich Felker2011-02-191-1/+1
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* race condition fix: block all signals before decrementing thread countRich Felker2011-02-193-22/+2
| | | | | | | | | | | | the existence of a (kernelspace) thread must never have observable effects after the thread count is decremented. if signals are not blocked, it could end up handling the signal for rsyscall and contributing towards the count of threads which have changed ids, causing a thread to be missed. this could lead to one thread retaining unwanted privilege level. this change may also address other subtle race conditions in application code that uses signals.
* make pthread_exit run dtors for last thread, wait to decrement thread countRich Felker2011-02-191-3/+3
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* add pthread_atfork interfaceRich Felker2011-02-181-0/+48
| | | | | | | | | note that this presently does not handle consistency of the libc's own global state during forking. as per POSIX 2008, if the parent process was threaded, the child process may only call async-signal-safe functions until one of the exec-family functions is called, so the current behavior is believed to be conformant even if non-ideal. it may be improved at some later time.
* reorganize pthread data structures and move the definitions to alltypes.hRich Felker2011-02-1723-83/+83
| | | | | | | | this allows sys/types.h to provide the pthread types, as required by POSIX. this design also facilitates forcing ABI-compatible sizes in the arch-specific alltypes.h, while eliminating the need for developers changing the internals of the pthread types to poke around with arch-specific headers they may not be able to test.
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-11-09 20:36:51 +0000