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* fix potential deadlock bug in libc-internal locking logicRich Felker2013-09-203-13/+15
| | | | | | | | | | | | | | | | | | | | if a multithreaded program became non-multithreaded (i.e. all other threads exited) while one thread held an internal lock, the remaining thread would fail to release the lock. the the program then became multithreaded again at a later time, any further attempts to obtain the lock would deadlock permanently. the underlying cause is that the value of libc.threads_minus_1 at unlock time might not match the value at lock time. one solution would be returning a flag to the caller indicating whether the lock was taken and needs to be unlocked, but there is a simpler solution: using the lock itself as such a flag. note that this flag is not needed anyway for correctness; if the lock is not held, the unlock code is harmless. however, the memory synchronization properties associated with a_store are costly on some archs, so it's best to avoid executing the unlock code when it is unnecessary.
* correct the sysconf value for RTSIG_MAXRich Felker2013-09-201-1/+2
| | | | | this is the number of realtime signals available, not the maximum signal number or total number of signals.
* fix sigemptyset and sigfillset for mipsRich Felker2013-09-162-1/+10
| | | | they were leaving junk in the upper bits.
* fix clobbering of caller's stack in mips __clone functionRich Felker2013-09-161-0/+3
| | | | | | | | | this was resulting in crashes in posix_spawn on mips, and would have affected applications calling clone too. since the prototype for __clone has it as a variadic function, it may not assume that 16($sp) is writable for use in making the syscall. instead, it needs to allocate additional stack space, and then adjust the stack pointer back in both of the code paths for the parent process/thread.
* omit CLONE_PARENT flag to clone in pthread_createRich Felker2013-09-161-1/+1
| | | | | | | | CLONE_PARENT is not necessary (CLONE_THREAD provides all the useful parts of it) and Linux treats CLONE_PARENT as an error in certain situations, without noticing that it would be a no-op due to CLONE_THREAD. this error case prevents, for example, use of a multi-threaded init process and certain usages with containers.
* use symbolic names for clone flags in pthread_createRich Felker2013-09-161-2/+5
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* support configurable page size on mips, powerpc and microblazeSzabolcs Nagy2013-09-1512-11/+24
| | | | | | | | | | | | | | | | 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 overflow in sysconf for _SC_MQ_PRIO_MAXRich Felker2013-09-141-1/+2
| | | | the value of MQ_PRIO_MAX does not fit, so it needs to use OFLOW.
* fix child stack alignment on mips cloneRich Felker2013-09-141-0/+1
| | | | | | unlike other archs, the mips version of clone was not doing anything to align the stack pointer. this seems to have been the cause for some SIGBUS crashes that were observed in posix_spawn.
* fix x86_64 lrintl asm, againRich Felker2013-09-131-2/+2
| | | | | | | | the underlying problem was not incorrect sign extension (fixed in the previous commit to this file by nsz) but that code that treats "long" as 32-bit was copied blindly from i386 to x86_64. now lrintl is identical to llrintl on x86_64, as it should be.
* do not use default when dynamic linker fails to open existing path fileRich Felker2013-09-091-0/+2
| | | | | | | | if fopen fails for a reason other than ENOENT, we must assume the intent is that the path file be used. failure may be due to misconfiguration or intentional resource-exhaustion attack (against suid programs), in which case falling back to loading libraries from an unintended path could be dangerous.
* math: remove STRICT_ASSIGN from exp2f (see previous commit)Szabolcs Nagy2013-09-061-1/+1
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* math: remove STRICT_ASSIGN macroSzabolcs Nagy2013-09-0611-23/+13
| | | | | | | | | | | | | gcc did not always drop excess precision according to c99 at assignments before version 4.5 even if -std=c99 was requested which caused badly broken mathematical functions on i386 when FLT_EVAL_METHOD!=0 but STRICT_ASSIGN was not used consistently and it is worked around for old compilers with -ffloat-store so it is no longer needed the new convention is to get the compiler respect c99 semantics and when excess precision is not harmful use float_t or double_t or to specialize code using FLT_EVAL_METHOD
* math: support invalid ld80 representations in fpclassifySzabolcs Nagy2013-09-051-2/+4
| | | | | | | apparently gnulib requires invalid long double representations to be handled correctly in printf so we classify them according to how the fpu treats them: bad inf is nan, bad nan is nan, bad normal is nan and bad subnormal/zero is minimal normal
* math: fix atanh (overflow and underflow issues)Szabolcs Nagy2013-09-053-14/+37
| | | | | | | in atanh exception handling was left to the called log functions, but the argument to those functions could underflow or overflow. use double_t and float_t to avoid some useless stores on x86
* math: remove libc.h include from libm.hSzabolcs Nagy2013-09-055-3/+5
| | | | libc.h is only for weak_alias so include it directly where it is used
* math: fix acoshf on negative valuesSzabolcs Nagy2013-09-052-7/+8
| | | | | | acosh(x) is invalid for x<1, acoshf tried to be clever using signed comparisions to handle all x<2 the same way, but the formula was wrong on large negative values.
* math: fix expm1l on x86_64 (avoid underflow for large negative x)Szabolcs Nagy2013-09-053-3/+13
| | | | copy the fix from i386: return -1 instead of exp2l(x)-1 when x <= -65
* math: fix lrintl.s on x86_64 (use movslq to signextend the result)Szabolcs Nagy2013-09-051-1/+1
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* math: fix exp2l asm on x86 (raise underflow correctly)Szabolcs Nagy2013-09-052-67/+78
| | | | | | | | | | | | | | | | there were two problems: * omitted underflow on subnormal results: exp2l(-16383.5) was calculated as sqrt(2)*2^-16384, the last bits of sqrt(2) are zero so the down scaling does not underflow eventhough the result is in subnormal range * spurious underflow for subnormal inputs: exp2l(0x1p-16400) was evaluated as f2xm1(x)+1 and f2xm1 raised underflow (because inexact subnormal result) the first issue is fixed by raising underflow manually if x is in (-32768,-16382] and not integer (x-0x1p63+0x1p63 != x) the second issue is fixed by treating x in (-0x1p64,0x1p64) specially for these fixes the special case handling was completely rewritten
* math: cosmetic cleanup (use explicit union instead of fshape and dshape)Szabolcs Nagy2013-09-0511-166/+140
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* math: remove *_WORD64 macros from libm.hSzabolcs Nagy2013-09-052-29/+13
| | | | only fma used these macros and the explicit union is clearer
* math: remove old longdbl.hSzabolcs Nagy2013-09-052-113/+0
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* math: long double fix (use ldshape union)Szabolcs Nagy2013-09-058-51/+24
| | | | | | * use new ldshape union consistently * add ld128 support to frexpl * simplify sqrtl comment (ld64 is not just arm)
* math: use float_t and double_t in scalbnf and scalbnSzabolcs Nagy2013-09-052-16/+20
| | | | | remove STRICT_ASSIGN (c99 semantics is assumed) and use the conventional union to prepare the scaling factor (so libm.h is no longer needed)
* math: fix remaining old long double code (erfl, fmal, lgammal, scalbnl)Szabolcs Nagy2013-09-055-93/+65
| | | | | in lgammal don't handle 1 and 2 specially, in fma use the new ldshape union instead of ld80 one.
* math: cbrt cleanup and long double fixSzabolcs Nagy2013-09-053-72/+59
| | | | | | | * use float_t and double_t * cleanup subnormal handling * bithacks according to the new convention (ldshape for long double and explicit unions for float and double)
* math: fix underflow in exp*.c and long double handling in exp2lSzabolcs Nagy2013-09-058-182/+139
| | | | | | | | | | | | * don't care about inexact flag * use double_t and float_t (faster, smaller, more precise on x86) * exp: underflow when result is zero or subnormal and not -inf * exp2: underflow when result is zero or subnormal and not exact * expm1: underflow when result is zero or subnormal * expl: don't underflow on -inf * exp2: fix incorrect comment * expm1: simplify special case handling and overflow properly * expm1: cleanup final scaling and fix negative left shift ub (twopk)
* math: long double trigonometric cleanup (cosl, sinl, sincosl, tanl)Szabolcs Nagy2013-09-058-236/+228
| | | | | | | | | | | | | | ld128 support was added to internal kernel functions (__cosl, __sinl, __tanl, __rem_pio2l) from freebsd (not tested, but should be a good start for when ld128 arch arrives) __rem_pio2l had some code cleanup, the freebsd ld128 code seems to gather the results of a large reduction with precision loss (fixed the bug but a todo comment was added for later investigation) the old copyright was removed from the non-kernel wrapper functions (cosl, sinl, sincosl, tanl) since these are trivial and the interesting parts and comments had been already rewritten.
* math: long double inverse trigonometric cleanup (acosl, asinl, atanl, atan2l)Szabolcs Nagy2013-09-056-103/+180
| | | | | | * added ld128 support from freebsd fdlibm (untested) * using new ldshape union instead of IEEEl2bits * inexact status flag is not supported
* math: rewrite hypotSzabolcs Nagy2013-09-053-324/+135
| | | | | | | | | | | | | | | | | | method: if there is a large difference between the scale of x and y then the larger magnitude dominates, otherwise reduce x,y so the argument of sqrt (x*x+y*y) does not overflow or underflow and calculate the argument precisely using exact multiplication. If the argument has less error than 1/sqrt(2) ~ 0.7 ulp, then the result has less error than 1 ulp in nearest rounding mode. the original fdlibm method was the same, except it used bit hacks instead of dekker-veltkamp algorithm, which is problematic for long double where different representations are supported. (the new hypot and hypotl code should be smaller and faster on 32bit cpu archs with fast fpu), the new code behaves differently in non-nearest rounding, but the error should be still less than 2ulps. ld80 and ld128 are supported
* math: rewrite remainder functions (remainder, remquo, fmod, modf)Szabolcs Nagy2013-09-0511-1010/+472
| | | | | | | | | * results are exact * modfl follows truncl (raises inexact flag spuriously now) * modf and modff only had cosmetic cleanup * remainder is just a wrapper around remquo now * using iterative shift+subtract for remquo and fmod * ld80 and ld128 are supported as well
* math: rewrite rounding functions (ceil, floor, trunc, round, rint)Szabolcs Nagy2013-09-0515-905/+274
| | | | | | | | | | * faster, smaller, cleaner implementation than the bit hacks of fdlibm * use arithmetics like y=(double)(x+0x1p52)-0x1p52, which is an integer neighbor of x in all rounding modes (0<=x<0x1p52) and only use bithacks when that's faster and smaller (for float it usually is) * the code assumes standard excess precision handling for casts * long double code supports both ld80 and ld128 * nearbyint is not changed (it is a wrapper around rint)
* math: fix logb(-0.0) in downward rounding modeSzabolcs Nagy2013-09-053-6/+6
| | | | | use -1/(x*x) instead of -1/(x+0) to return -inf, -0+0 is -0 in downward rounding mode
* math: ilogb cleanupSzabolcs Nagy2013-09-053-16/+43
| | | | | | | * consistent code style * explicit union instead of typedef for double and float bit access * turn FENV_ACCESS ON to make 0/0.0f raise invalid flag * (untested) ld128 version of ilogbl (used by logbl which has ld128 support)
* long double cleanup, initial commitSzabolcs Nagy2013-09-058-96/+89
| | | | | | | | new ldshape union, ld128 support is kept, code that used the old ldshape union was rewritten (IEEEl2bits union of freebsd libm is not touched yet) ld80 __fpclassifyl no longer tries to handle invalid representation
* fix typo in comment in __randnameRich Felker2013-09-041-1/+1
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* fix mips-specific bug in synccall (too little space for signal mask)Rich Felker2013-09-021-5/+3
| | | | | switch to the new __block_all_sigs/__restore_sigs internal API to clean up the code too.
* in synccall, ignore the signal before any threads' signal handlers returnRich Felker2013-09-021-4/+4
| | | | | | this protects against deadlock from spurious signals (e.g. sent by another process) arriving after the controlling thread releases the other threads from the sync operation.
* fix invalid pointer in synccall (multithread setuid, etc.)Rich Felker2013-09-021-0/+1
| | | | | | | the head pointer was not being reset between calls to synccall, so any use of this interface more than once would build the linked list incorrectly, keeping the (now invalid) list nodes from the previous call.
* fix special-case breakage in popen due to reversed argument orderRich Felker2013-09-011-1/+1
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* fix missing return value warning in faccessat, minor cleanupRich Felker2013-08-311-1/+1
| | | | | clone will pass the return value of the start function to SYS_exit anyway; there's no need to call the syscall directly.
* fix invalid %m format crash in wide scanf variantsRich Felker2013-08-311-0/+2
| | | | the wide variant was missed in the previous commit.
* avoid crash in scanf when invalid %m format is encounteredRich Felker2013-08-311-0/+2
| | | | | | | invalid format strings invoke undefined behavior, so this is not a conformance issue, but it's nicer for scanf to report the error safely instead of calling free on a potentially-uninitialized pointer or a pointer to memory belonging to the caller.
* remove incorrect cancellation points from realpathRich Felker2013-08-311-4/+4
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* debloat realpath's allocation strategyRich Felker2013-08-311-12/+6
| | | | | | | | | rather than allocating a PATH_MAX-sized buffer when the caller does not provide an output buffer, work first with a PATH_MAX-sized temp buffer with automatic storage, and either copy it to the caller's buffer or strdup it on success. this not only avoids massive memory waste, but also avoids pulling in free (and thus the full malloc implementation) unnecessarily in static programs.
* make realpath use O_PATH when opening the fileRich Felker2013-08-311-1/+1
| | | | | | this avoids failure if the file is not readable and avoids odd behavior for device nodes, etc. on old kernels that lack O_PATH, the old behavior (O_RDONLY) will naturally happen as the fallback.
* fix breakage in synccall due to incorrect signal restoration in sigqueueRich Felker2013-08-311-2/+3
| | | | | | | | | | | | commit 07827d1a82fb33262f686eda959857f0d28cd8fa seems to have introduced this issue. sigqueue is called from the synccall core, at which time, even implementation-internal signals are blocked. however, pthread_sigmask removes the implementation-internal signals from the old mask before returning, so that a process which began life with them blocked will not be able to save a signal mask that has them blocked, possibly causing them to become re-blocked later. however, this was causing sigqueue to unblock the implementation-internal signals during synccall, leading to deadlock.
* optimized C memcpyRich Felker2013-08-281-16/+111
| | | | | | | | | | | | | | | | unlike the old C memcpy, this version handles word-at-a-time reads and writes even for misaligned copies. it does not require that the cpu support misaligned accesses; instead, it performs bit shifts to realign the bytes for the destination. essentially, this is the C version of the ARM assembly language memcpy. the ideas are all the same, and it should perform well on any arch with a decent number of general-purpose registers that has a barrel shift operation. since the barrel shifter is an optional cpu feature on microblaze, it may be desirable to provide an alternate asm implementation on microblaze, but otherwise the C code provides a competitive implementation for "generic risc-y" cpu archs that should alleviate the urgent need for arch-specific memcpy asm.
* fix invalid instruction mnemonics in powerpc fenv asmRich Felker2013-08-271-3/+3
| | | | | there is no non-dot version of the andis instruction, but there's no harm in updating the flags anyway, so just use the dot version.
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