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* some initial math asm for armhf (fabs[f] and sqrt[f])Rich Felker2013-08-1612-0/+32
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* support floating point environment (fenv) on armhf (hard float) subarchsRich Felker2013-08-163-0/+62
| | | | | patch by nsz. I've tested it on an armhf machine and it seems to be working correctly.
* fix build of x86_64 expl assemblyRich Felker2013-08-161-1/+1
| | | | | apparently this label change was not carried over when adapting the changes from the i386 version.
* math: fix pow(x,-1) to raise underflow properlySzabolcs Nagy2013-08-151-2/+14
| | | | | | if FLT_EVAL_METHOD!=0 check if (double)(1/x) is subnormal and not a power of 2 (if 1/x is power of 2 then either it is exact or the long double to double rounding already raised inexact and underflow)
* math: fix i386 atan2.s to raise underflow for subnormal resultsSzabolcs Nagy2013-08-152-2/+24
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* math: clean up atan2.cSzabolcs Nagy2013-08-154-103/+73
| | | | | | | | | * remove volatile hacks * don't care about inexact flag for now (removed all the +-tiny) * fix atanl to raise underflow properly * remove signed int arithmetics * use pi/2 instead of pi_o_2 (gcc generates the same code, which is not correct, but it does not matter: we mainly care about nearest rounding)
* math: fix x86 asin, atan, exp, log1p to raise underflowSzabolcs Nagy2013-08-156-3/+98
| | | | | | underflow is raised by an inexact subnormal float store, since subnormal operations are slow, check the underflow flag and skip the store if it's already raised
* math: fix x86 expl.s to raise underflow and clean up special case handlingSzabolcs Nagy2013-08-152-45/+31
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* math: fix asin, atan, log1p, tanh to raise underflow on subnormalSzabolcs Nagy2013-08-159-26/+39
| | | | | | | | | | | | | | | | | | for these functions f(x)=x for small inputs, because f(0)=0 and f'(0)=1, but for subnormal values they should raise the underflow flag (required by annex F), if they are approximated by a polynomial around 0 then spurious underflow should be avoided (not required by annex F) all these functions should raise inexact flag for small x if x!=0, but it's not required by the standard and it does not seem a worthy goal, so support for it is removed in some cases. raising underflow: - x*x may not raise underflow for subnormal x if FLT_EVAL_METHOD!=0 - x*x may raise spurious underflow for normal x if FLT_EVAL_METHOD==0 - in case of double subnormal x, store x as float - in case of float subnormal x, store x*x as float
* math: fix tgamma to raise underflow for large negative valuesSzabolcs Nagy2013-08-151-0/+1
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* math: fix pow(0,-inf) to raise divbyzero flagSzabolcs Nagy2013-08-152-2/+2
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* math: minor scalbn*.c simplificationSzabolcs Nagy2013-08-153-18/+10
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* fix length computation in dn_expandRich Felker2013-08-141-3/+5
| | | | | | | there are two possible points where the length is evaluated: either the first 'compression' jump, or the null terminator if no jumps have taken place yet. the previous code only measured the length of the first component.
* de-duplicate dn_expand, fix return value and signature, clean upRich Felker2013-08-142-48/+23
| | | | | | | | | | | | | | | | | the duplicate code in dn_expand and its incorrect return values are both results of the history of the code: the version in __dns.c was originally written with no awareness of the legacy resolver API, and was later copy-and-paste duplicated to provide the legacy API. this commit is the first of a series that will restructure the internal dns code to share as much code as possible with the legacy resolver API functions. I have also removed the loop detection logic, since the output buffer length limit naturally prevents loops. in order to avoid long runtime when encountering a loop if the caller provided a ridiculously long buffer, the caller-provided length is clamped at the maximum dns name length.
* add arm-optimized memcpy implementation from bionic libcRich Felker2013-08-143-0/+383
| | | | | | | | | | | | | | | | | | | | the approach of this implementation was heavily investigated prior to adopting it. attempts to obtain similar performance with pure C code were capping out at about 75% of the performance of the asm, with considerably larger code size, and were fragile in that the compiler would sometimes compile part of memcpy into a call to itself. therefore, just using the asm seems to be the best option. this commit is the first to make use of the new subarch-specific asm framework. the new armel directory is the location for arm asm that should not be used for all arm subarchs, only the default one. armhf is the name of the little-endian hardfloat-ABI subarch, which can use the exact same asm. in both cases, the build system finds the asm by following a memcpy.sub file. the other two subarchs, armeb and armebhf, would need a big-endian variant of this code. it would not be hard to adapt the code to big endian, but I will hold off on doing so until there is demand for it.
* fix _NSIG and SIGRTMAX on mipsRich Felker2013-08-101-1/+3
| | | | | | | | | | | | | | | | | | | | | a mips signal mask contains 128 bits, enough for signals 1 through 128. however, the exit status obtained from the wait-family functions only has room for values up to 127. reportedly signal 128 was causing kernelspace bugs, so it was removed from the kernel recently; even without that issue, however, it was impossible to support it correctly in userspace. at the same time, the bug was masked on musl by SIGRTMAX incorrectly yielding 64 on mips, rather than the "correct" value of 128. now that the _NSIG issue is fixed, SIGRTMAX can be fixed at the same time, exposing the full range of signals for application use. note that the (nonstandardized) libc _NSIG value is actually one greater than the max signal number, and also one greater than the kernel headers' idea of _NSIG. this is the reason for the discrepency with the recent kernel changes. since reducing _NSIG by one brought it down from 129 to 128, rather than from 128 to 127, _NSIG/8, used widely in the musl sources, is unchanged.
* add pthread_setaffinity_np and pthread_getaffinity_np functionsRich Felker2013-08-103-18/+26
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* add cpu affinity interfacesRich Felker2013-08-103-0/+29
| | | | | | | this first commit just includes the CPU_* and sched_* interfaces, not the pthread_* interfaces, which may be added later. simple sanity-check testing has been done for the basic interfaces, but most of the macros have not yet been tested.
* change sigset_t functions to restrict to _NSIGRich Felker2013-08-094-5/+5
| | | | | | | the idea here is to avoid advertising signals that don't exist and to make these functions safe to call (e.g. from within other parts of the implementation) on fake sigset_t objects which do not have the HURD padding.
* optimize posix_spawn to avoid spurious sigaction syscallsRich Felker2013-08-093-12/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | the trick here is that sigaction can track for us which signals have ever had a signal handler set for them, and only those signals need to be considered for reset. this tracking mask may have false positives, since it is impossible to remove bits from it without race conditions. false negatives are not possible since the mask is updated with atomic operations prior to making the sigaction syscall. implementation-internal signals are set to SIG_IGN rather than SIG_DFL so that a signal raised in the parent (e.g. calling pthread_cancel on the thread executing pthread_spawn) does not have any chance make it to the child, where it would cause spurious termination by signal. this change reduces the minimum/typical number of syscalls in the child from around 70 to 4 (including execve). this should greatly improve the performance of posix_spawn and other interfaces which use it (popen and system). to facilitate these changes, sigismember is also changed to return 0 rather than -1 for invalid signals, and to return the actual status of implementation-internal signals. POSIX allows but does not require an error on invalid signal numbers, and in fact returning an error tends to confuse applications which wrongly assume the return value of sigismember is boolean.
* fix missing errno from exec failure in posix_spawnRich Felker2013-08-091-0/+1
| | | | | failures prior to the exec attempt were reported correctly, but on exec failure, the return value contained junk.
* block all signals, even implementation-internal ones, in faccessat childRich Felker2013-08-091-1/+1
| | | | | | the child process's stack may be insufficient size to support a signal frame, and there is no reason these signal handlers should run in the child anyway.
* block signals during forkRich Felker2013-08-081-0/+3
| | | | | | | | | | | there are several reasons for this. some of them are related to race conditions that arise since fork is required to be async-signal-safe: if fork or pthread_create is called from a signal handler after the fork syscall has returned but before the subsequent userspace code has finished, inconsistent state could result. also, there seem to be kernel and/or strace bugs related to arrival of signals during fork, at least on some versions, and simply blocking signals eliminates the possibility of such bugs.
* work around libraries with versioned symbols in dynamic linkerRich Felker2013-08-081-11/+14
| | | | | | | | | | | | | | | | this commit does not add versioning support; it merely fixes incorrect lookups of symbols in libraries that contain versioned symbols. previously, the version information was completely ignored, and empirically this seems to have resulted in the oldest version being chosen, but I am uncertain if that behavior was even reliable. the new behavior being introduced is to completely ignore symbols which are marked "hidden" (this seems to be the confusing nomenclature for non-current-version) when versioning is present. this should solve all problems related to libraries with symbol versioning as long as all binaries involved are up-to-date (compatible with the latest-version symbols), and it's the needed behavior for dlsym under all circumstances.
* add Big5 charset support to iconvRich Felker2013-08-072-0/+1066
| | | | | | at this point, it is just the common base charset equivalent to Windows CP 950, with no further extensions. HKSCS and possibly other supersets will be added later. other aliases may need to be added too.
* make fcvt decimal point location for zero make more senseRich Felker2013-08-071-1/+1
| | | | | | | | | | the (obsolete) standard allows either 0 or 1 for the decimal point location in this case, but since the number of zero digits returned in the output string (in this implementation) is one more than the number of digits the caller requested, it makes sense for the decimal point to be logically "after" the first digit. in a sense, this change goes with the previous commit which fixed the value of the decimal point location for non-zero inputs.
* fix ecvt/fcvt decimal point position outputRich Felker2013-08-071-1/+1
| | | | | | | | | | | these functions are obsolete and have no modern standard. the text in SUSv2 is highly ambiguous, specifying that "negative means to the left of the returned digits", which suggested to me that 0 would mean to the right of the first digit. however, this does not agree with historic practice, and the Linux man pages are more clear, specifying that a negative value means "that the decimal point is to the left of the start of the string" (in which case, 0 would mean the start of the string, in accordance with historic practice).
* iconv support for legacy Korean encodingsRich Felker2013-08-052-0/+678
| | | | | | | | | | | | | | | | | | | | | like for other character sets, stateful iso-2022 form is not supported yet but everything else should work. all charset aliases are treated the same, as Windows codepage 949, because reportedly the EUC-KR charset name is in widespread (mis?)usage in email and on the web for data which actually uses the extended characters outside the standard 93x94 grid. this could easily be changed if desired. the principle of this converter for handling the giant bulk of rare Hangul syllables outside of the standard KS X 1001 93x94 grid is the same as the GB18030 converter's treatment of non-explicitly-coded Unicode codepoints: sequences in the extension range are mapped to an integer index N, and the converter explicitly computes the Nth Hangul syllable not explicitly encoded in the character map. empirically, this requires at most 7 passes over the grid. this approach reduces the table size required for Korean legacy encodings from roughly 44k to 17k and should have minimal performance impact on real-world text conversions since the "slow" characters are rare. where it does have impact, the cost is merely a large constant time factor.
* have new timer threads unblock their own SIGTIMERRich Felker2013-08-031-2/+2
| | | | | | | unblocking it in the pthread_once init function is not sufficient, since multiple threads, some of them with the signal blocked, could already exist before this is called; timers started from such threads would be non-functional.
* add system for resetting TLS to initial valuesRich Felker2013-08-034-14/+56
| | | | | | | | | | | | | | | this is needed for reused threads in the SIGEV_THREAD timer notification system, and could be reused elsewhere in the future if needed, though it should be refactored for such use. for static linking, __init_tls.c is simply modified to export the TLS info in a structure with external linkage, rather than using statics. this perhaps makes the code more clear, since the statics were poorly named for statics. the new __reset_tls.c is only linked if it is used. for dynamic linking, the code is in dynlink.c. sharing code with __copy_tls is not practical since __reset_tls must also re-zero thread-local bss.
* fix multiple bugs in SIGEV_THREAD timersRich Felker2013-08-036-22/+36
| | | | | | | | | | | | | | | | | | 1. the thread result field was reused for storing a kernel timer id, but would be overwritten if the application code exited or cancelled the thread. 2. low pointer values were used as the indicator that the timer id is a kernel timer id rather than a thread id. this is not portable, as mmap may return low pointers on some conditions. instead, use the fact that pointers must be aligned and kernel timer ids must be non-negative to map pointers into the negative integer space. 3. signals were not blocked until after the timer thread started, so a race condition could allow a signal handler to run in the timer thread when it's not supposed to exist. this is mainly problematic if the calling thread was the only thread where the signal was unblocked and the signal handler assumes it runs in that thread.
* fix faccessat to support AT_EACCESS flagRich Felker2013-08-031-1/+46
| | | | | | | | | | | | | | this is another case of the kernel syscall failing to support flags where it needs to, leading to horrible workarounds in userspace. this time the workaround requires changing uid/gid, and that's not safe to do in the current process. in the worst case, kernel resource limits might prevent recovering the original values, and then there would be no way to safely return. so, use the safe but horribly inefficient alternative: forking. clone is used instead of fork to suppress signals from the child. fortunately this worst-case code is only needed when effective and real ids mismatch, which mainly happens in suid programs.
* collapse euidaccess to a call to faccessatRich Felker2013-08-031-9/+1
| | | | | | it turns out Linux is buggy for faccessat, just like fchmodat: the kernel does not actually take a flags argument. so we're going to have to emulate it there.
* add legacy euidaccess function and eaccess alias for itRich Felker2013-08-031-0/+18
| | | | this is mainly for ABI compat purposes.
* make tdestroy allow null function pointer if no destructor is neededRich Felker2013-08-021-1/+1
| | | | this change is to align with a change in the glibc interface.
* fix aliasing violations in tsearch functionsRich Felker2013-08-021-2/+10
| | | | | | | patch by nsz. the actual object the caller has storing the tree root has type void *, so accessing it as struct node * is not valid. instead, simply access the value, move it to a temporary of the appropriate type and work from there, then move the result back.
* protect against long double type mismatches (mainly powerpc for now)Rich Felker2013-08-021-0/+7
| | | | | | check in configure to be polite (failing early if we're going to fail) and in vfprintf.c since that is the point at which a mismatching type would be extremely dangerous.
* add legacy function vallocRich Felker2013-08-021-0/+8
| | | | it was already declared in stdlib.h, but not defined anywhere.
* add wcsftime_t aliasRich Felker2013-08-021-0/+3
| | | | this is a nonstandard extension.
* make fchdir, fchmod, fchown, and fstat support O_PATH file descriptorsRich Felker2013-08-024-5/+37
| | | | | | | | | on newer kernels, fchdir and fstat work anyway. this same fix should be applied to any other syscalls that are similarly affected. with this change, the current definitions of O_SEARCH and O_EXEC as O_PATH are mostly conforming to POSIX requirements. the main remaining issue is that O_NOFOLLOW has different semantics.
* debloat code that depends on /proc/self/fd/%d with shared functionRich Felker2013-08-025-6/+26
| | | | | | | I intend to add more Linux workarounds that depend on using these pathnames, and some of them will be in "syscall" functions that, from an anti-bloat standpoint, should not depend on the whole snprintf framework.
* work around linux's lack of flags argument to fchmodat syscallRich Felker2013-08-021-1/+29
| | | | | | | | | | | | | | | | | | | previously, the AT_SYMLINK_NOFOLLOW flag was ignored, giving dangerously incorrect behavior -- the target of the symlink had its modes changed to the modes (usually 0777) intended for the symlink). this issue was amplified by the fact that musl provides lchmod, as a wrapper for fchmodat, which some archival programs take as a sign that symlink modes are supported and thus attempt to use. emulating AT_SYMLINK_NOFOLLOW was a difficult problem, and I originally believed it could not be solved, at least not without depending on kernels newer than 3.5.x or so where O_PATH works halfway well. however, it turns out that accessing O_PATH file descriptors via their pseudo-symlink entries in /proc/self/fd works much better than trying to use the fd directly, and works even on older kernels. moreover, the kernel has permanently pegged these references to the inode obtained by the O_PATH open, so there should not be race conditions with the file being moved, deleted, replaced, etc.
* move RPATH search after LD_LIBRARY_PATH searchRich Felker2013-08-021-2/+2
| | | | | | | | | this is the modern way, and the only way that makes any sense. glibc has this complicated mechanism with RPATH and RUNPATH that controls whether RPATH is processed before or after LD_LIBRARY_PATH, presumably to support legacy binaries, but there is no compelling reason to support this, and better behavior is obtained by just fixing the search order.
* if map_library has allocated a buffer for phdrs, free it on success tooRich Felker2013-08-021-0/+1
| | | | this fixes an oversight in the previous commit.
* improve error handling in map_library and support long phdrsRich Felker2013-08-021-12/+21
| | | | | | | previously, errno could be meaningless when the caller wrote it to the dlerror string or stderr. try to make it meaningful. also, fix incorrect check for over-long program headers and instead actually support them by allocating memory if needed.
* fix uninitialized dyn variable in map_libraryRich Felker2013-08-021-1/+1
| | | | | this can only happen for invalid library files, but they were not detected reliably because the variable was uninitialized.
* fix (deprecated) mktemp logic and update it to match other temp functionsRich Felker2013-08-021-4/+11
| | | | | | | | the access function cannot be used to check for existence, because it operates using real uid/gid rather than effective to determine accessibility; this matters for the non-final path components. instead, use stat. failure of stat is success if only the final component is missing (ENOENT) and otherwise is failure.
* remove (no longer useful) namespace-protected __mktemp symbolRich Felker2013-08-021-4/+1
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* make mkdtemp and mkstemp family leave template unchanged on failRich Felker2013-08-022-13/+18
| | | | | | also refactor mkdtemp based on new shared temp code, removing dependency on the deprecated mktemp, whose behavior made this logic more difficult.
* optimized memset asm for i386 and x86_64Rich Felker2013-08-012-0/+88
| | | | | | | | | | | | | | | | | | | | the concept of both versions is the same; they differ only in details. for long runs, they use "rep movsl" or "rep movsq", and for small runs, they use a trick, writing from both ends towards the middle, that reduces the number of branches needed. in addition, if memset is called multiple times with the same length, all branches will be predicted; there are no loops. for larger runs, there are likely faster approaches than "rep", at least on some cpu models. for 32-bit, it's unlikely that there is any faster approach that does not require non-baseline instructions; doing anything fancier would require inspecting cpu capabilities. for 64-bit, there may very well be faster versions that work on all models; further optimization could be explored in the future. with these changes, memset is anywhere between 50% faster and 6 times faster, depending on the cpu model and the length and alignment of the destination buffer.
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