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2011-03-28fix getc - the classic error of trying to store EOF+0-255 in a char type..Rich Felker-3/+3
2011-03-28major stdio overhaul, using readv/writev, plus other changesRich Felker-281/+258
the biggest change in this commit is that stdio now uses readv to fill the caller's buffer and the FILE buffer with a single syscall, and likewise writev to flush the FILE buffer and write out the caller's buffer in a single syscall. making this change required fundamental architectural changes to stdio, so i also made a number of other improvements in the process: - the implementation no longer assumes that further io will fail following errors, and no longer blocks io when the error flag is set (though the latter could easily be changed back if desired) - unbuffered mode is no longer implemented as a one-byte buffer. as a consequence, scanf unreading has to use ungetc, to the unget buffer has been enlarged to hold at least 2 wide characters. - the FILE structure has been rearranged to maintain the locations of the fields that might be used in glibc getc/putc type macros, while shrinking the structure to save some space. - error cases for fflush, fseek, etc. should be more correct. - library-internal macros are used for getc_unlocked and putc_unlocked now, eliminating some ugly code duplication. __uflow and __overflow are no longer used anywhere but these macros. switch to read or write mode is also separated so the code can be better shared, e.g. with ungetc. - lots of other small things.
2011-03-25match glibc/lsb cancellation abi on i386Rich Felker-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.
2011-03-25fix all implicit conversion between signed/unsigned pointersRich Felker-48/+44
sadly the C language does not specify any such implicit conversion, so this is not a matter of just fixing warnings (as gcc treats it) but actual errors. i would like to revisit a number of these changes and possibly revise the types used to reduce the number of casts required.
2011-03-24simplify and optimize FILE lock handlingRich Felker-14/+14
2011-03-24prepare pthread_spin_unlock for archs that need memory barriersRich Felker-1/+2
2011-03-24optimize contended case for pthread_spin_trylockRich Felker-1/+2
2011-03-24optimize spinlock spinRich Felker-1/+1
2011-03-24fix non-atomicity of putsRich Felker-1/+5
2011-03-24overhaul cancellation to fix resource leaks and dangerous behavior with signalsRich Felker-13/+43
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...
2011-03-23very cheap double-free checks in mallocRich Felker-0/+4
2011-03-20global cleanup to use the new syscall interfaceRich Felker-238/+180
2011-03-19if returning errno value directly from a syscall, we need to negate it.Rich Felker-3/+3
2011-03-19syscall overhaul part two - unify public and internal syscall interfaceRich Felker-31/+53
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.
2011-03-19remove comment cruft that got left behind in x86_64 syscall.sRich Felker-1/+0
2011-03-19overhaul syscall interfaceRich Felker-13/+67
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.
2011-03-18various legacy and linux-specific stuffRich Felker-0/+5
this commit is part of an effort to make more of busybox work out-of-the-box.
2011-03-18implement [v]swprintfRich Felker-1/+61
2011-03-17implement wprintf family of functionsRich Felker-0/+387
this implementation is extremely ugly and inefficient, but it avoids a good deal of code duplication and bloat. it may be cleaned up later to eliminate the remaining code duplication and some of the warts, but i don't really care about its performance. note that swprintf is not yet implemented.
2011-03-17fix broken wmemchr (unbounded search)Rich Felker-1/+1
2011-03-17implement robust mutexesRich Felker-10/+83
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.
2011-03-17avoid function call to pthread_self in mutex unlockRich Felker-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.
2011-03-17reorder mutex struct fields to make room for pointers (upcoming robust mutexes)Rich Felker-1/+3
the layout has been chosen so that pointer slots 3 and 4 fit between the integer slots on 32-bit archs, and come after the integer slots on 64-bit archs.
2011-03-17unify lock and owner fields of mutex structureRich Felker-8/+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.
2011-03-17optimize contended normal mutex case; add int compare-and-swap atomicRich Felker-1/+1
2011-03-16simplify logic, slightly optimize contended case for non-default mutex typesRich Felker-4/+2
2011-03-16correct error returns for error-checking mutexesRich Felker-2/+6
2011-03-16cut out a syscall on thread creation in the case where guard size is 0Rich Felker-1/+1
2011-03-16don't expose EAGAIN, etc. from timed futex wait to callerRich Felker-1/+4
2011-03-16optimize file locking: avoid cache-polluting writes to global storageRich Felker-3/+5
2011-03-14partially-written draft of fmemopen, still in #if 0Rich Felker-3/+48
2011-03-12misplaced & in times() made it fail to work, and clobber the stackRich Felker-1/+1
2011-03-12implement flockfile api, rework stdio lockingRich Felker-15/+66
2011-03-11implement dummy pthread_attr_[gs]etschedparam functionsRich Felker-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.
2011-03-11fix pthread_attr_* implementations to match corrected prototypesRich Felker-4/+4
2011-03-10fix failure behavior of sem_open when sem does not existRich Felker-1/+5
2011-03-10fix some semaphore wait semantics (race condition deadlock and error checking)Rich Felker-1/+7
2011-03-10fix sem_open and sem_close to obey posix semanticsRich Felker-38/+85
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.
2011-03-10optimize pthread termination in the non-detached caseRich Felker-4/+16
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.
2011-03-10fix errors in sigqueue (potential information leak, wrong behavior)Rich Felker-5/+7
1. any padding in the siginfo struct was not necessarily zero-filled, so it might have contained private data off the caller's stack. 2. the uid and pid must be filled in from userspace. the previous rsyscall fix broke rsyscalls because the values were always incorrect.
2011-03-10security fix: check that cancel/rsyscall signal was sent by the process itselfRich Felker-0/+3
2011-03-10more cancellation points: tcdrain, clock_nanosleepRich Felker-2/+12
2011-03-10remove useless return value checks for functions that cannot failRich Felker-3/+2
2011-03-10make sigsuspend a cancellation pointRich Felker-1/+6
2011-03-10make sigtimedwait a cancellation pointRich Felker-0/+3
2011-03-10don't fail with EINTR in sigtimedwaitRich Felker-6/+6
POSIX allows either behavior, but sigwait is not allowed to fail with EINTR, so the retry loop would have to be in one or the other anyway.
2011-03-10fix sigsuspend syscallRich Felker-1/+1
2011-03-10make sigaltstack work (missing macros in signal.h, error conditions)Rich Felker-1/+11
2011-03-10fix errno behavior in clock_* functionsRich Felker-3/+0
these functions are specified inconsistent in whether they're specified to return an error value, or return -1 and set errno. hopefully now they all match what POSIX requires.
2011-03-09fix error handling for pthread_sigmaskRich Felker-1/+15
it must return errno, not -1, and should reject invalud values for how.