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* overhaul aio implementation for correctnessRich Felker2015-02-131-110/+0
| | | | | | | | | | | | | | | | | | | | | | | | previously, aio operations were not tracked by file descriptor; each operation was completely independent. this resulted in non-conforming behavior for non-seekable/append-mode writes (which are required to be ordered) and made it impossible to implement aio_cancel, which in turn made closing file descriptors with outstanding aio operations unsafe. the new implementation is significantly heavier (roughly twice the size, and seems to be slightly slower) and presently aims mainly at correctness, not performance. most of the public interfaces have been moved into a single file, aio.c, because there is little benefit to be had from splitting them. whenever any aio functions are used, aio_cancel and the internal queue lifetime management and fd-to-queue mapping code must be linked, and these functions make up the bulk of the code size. the close function's interaction with aio is implemented with weak alias magic, to avoid pulling in heavy aio cancellation code in programs that don't use aio, and the expensive cancellation path (which includes signal blocking) is optimized out when there are no active aio queues.
* add missing legacy LFS *64 symbol aliasesSzabolcs Nagy2014-09-051-0/+3
| | | | | | versionsort64, aio*64 and lio*64 symbols were missing, they are only needed for glibc ABI compatibility, on the source level dirent.h and aio.h already redirect them.
* 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 invalid access in aio notificationRich Felker2013-06-161-1/+1
| | | | | | | issue found and patch provided by Jens Gustedt. after the atomic store to the error code field of the aiocb, the application is permitted to free or reuse the storage, so further access is invalid. instead, use the local copy that was already made.
* 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).
* stupid typo (caused by rather ugly spelling in POSIX..) in aioRich Felker2011-09-281-1/+1
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* fix return types for aio_read and aio_write againRich Felker2011-09-131-2/+2
| | | | | previous fix was backwards and propagated the wrong type rather than the right one...
* implement POSIX asynchronous ioRich Felker2011-09-091-0/+104
some features are not yet supported, and only minimal testing has been performed. should be considered experimental at this point.