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* eliminate use of cached pid from thread structureRich Felker2014-07-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | the main motivation for this change is to remove the assumption that the tid of the main thread is also the pid of the process. (the value returned by the set_tid_address syscall was used to fill both fields despite it semantically being the tid.) this is historically and presently true on linux and unlikely to change, but it conceivably could be false on other systems that otherwise reproduce the linux syscall api/abi. only a few parts of the code were actually still using the cached pid. in a couple places (aio and synccall) it was a minor optimization to avoid a syscall. caching could be reintroduced, but lazily as part of the public getpid function rather than at program startup, if it's deemed important for performance later. in other places (cancellation and pthread_kill) the pid was completely unnecessary; the tkill syscall can be used instead of tgkill. this is actually a rather subtle issue, since tgkill is supposedly a solution to race conditions that can affect use of tkill. however, as documented in the commit message for commit 7779dbd2663269b465951189b4f43e70839bc073, tgkill does not actually solve this race; it just limits it to happening within one process rather than between processes. we use a lock that avoids the race in pthread_kill, and the use in the cancellation signal handler is self-targeted and thus not subject to tid reuse races, so both are safe regardless of which syscall (tgkill or tkill) is used.
* support configurable page size on mips, powerpc and microblazeSzabolcs Nagy2013-09-151-1/+1
| | | | | | | | | | | | | | | | PAGE_SIZE was hardcoded to 4096, which is historically what most systems use, but on several archs it is a kernel config parameter, user space can only know it at execution time from the aux vector. PAGE_SIZE and PAGESIZE are not defined on archs where page size is a runtime parameter, applications should use sysconf(_SC_PAGE_SIZE) to query it. Internally libc code defines PAGE_SIZE to libc.page_size, which is set to aux[AT_PAGESZ] in __init_libc and early in __dynlink as well. (Note that libc.page_size can be accessed without GOT, ie. before relocations are done) Some fpathconf settings are hardcoded to 4096, these should be actually queried from the filesystem using statfs.
* fix uninitialized variable in lio (aio) codeRich Felker2013-06-161-1/+1
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* fix lio_listio return value in LIO_WAIT modeSzabolcs Nagy2013-01-131-1/+1
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* use alternate argument syntax for restrict with lio_listioRich Felker2012-12-041-1/+1
| | | | | | | for some reason I have not been able to determine, gcc 3.2 rejects the array notation. this seems to be a gcc bug, but since it's easy to work around, let's do the workaround and avoid gratuitously requiring newer compilers.
* clean up sloppy nested inclusion from pthread_impl.hRich Felker2012-11-081-0/+3
| | | | | | | | | | | | | | this mirrors the stdio_impl.h cleanup. one header which is not strictly needed, errno.h, is left in pthread_impl.h, because since pthread functions return their error codes rather than using errno, nearly every single pthread function needs the errno constants. in a few places, rather than bringing in string.h to use memset, the memset was replaced by direct assignment. this seems to generate much better code anyway, and makes many functions which were previously non-leaf functions into leaf functions (possibly eliminating a great deal of bloat on some platforms where non-leaf functions require ugly prologue and/or epilogue).
* use restrict everywhere it's required by c99 and/or posix 2008Rich Felker2012-09-061-2/+2
| | | | | | | | to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
* fix idiotic const-correctness error in lio_listioRich Felker2011-09-161-1/+1
| | | | | i blame this one on posix for using hideous const-qualified double pointers which are unusable without hideous casts.
* implement POSIX asynchronous ioRich Felker2011-09-091-0/+140
some features are not yet supported, and only minimal testing has been performed. should be considered experimental at this point.