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2014-11-19overhaul ARM atomics/tls for performance and compatibilityRich Felker-56/+331
previously, builds for pre-armv6 targets hard-coded use of the "kuser helper" system for atomics and thread-pointer access, resulting in binaries that fail to run (crash) on systems where this functionality has been disabled (as a security/hardening measure) in the kernel. additionally, builds for armv6 hard-coded an outdated/deprecated memory barrier instruction which may require emulation (extremely slow) on future models. this overhaul replaces the behavior for all pre-armv7 builds (both of the above cases) to perform runtime detection of the appropriate mechanisms for barrier, atomic compare-and-swap, and thread pointer access. detection is based on information provided by the kernel in auxv: presence of the HWCAP_TLS bit for AT_HWCAP and the architecture version encoded in AT_PLATFORM. direct use of the instructions is preferred when possible, since probing for the existence of the kuser helper page would be difficult and would incur runtime cost. for builds targeting armv7 or later, the runtime detection code is not compiled at all, and much more efficient versions of the non-cas atomic operations are provided by using ldrex/strex directly rather than wrapping cas.
2014-11-19save auxv pointer into libc struct early in dynamic linker startupRich Felker-0/+1
this allows most code to assume it has already been saved, and is a prerequisite for upcoming changes for arm atomic/tls operations.
2014-11-15getopt: fix optional argument processingFelix Fietkau-2/+2
Processing an option character with optional argument fails if the option is last on the command line. This happens because the if (optind >= argc) check runs first before testing for optional argument.
2014-11-15implement a private state for the uchar.h functionsJens Gustedt-0/+6
The C standard is imperative on that: 7.28.1 ... If ps is a null pointer, each function uses its own internal mbstate_t object instead, which is initialized at program startup to the initial conversion state; and these functions are also not supposed to implicitly use the state of the wchar.h functions: 7.29.6.3 ... The implementation behaves as if no library function calls these functions with a null pointer for ps. Previously this resulted in two bugs. - The functions c16rtomb and mbrtoc16 would crash when called with ps set to null. - The function mbrtoc32 used the private state of mbrtowc, which it is not allowed to do.
2014-11-15fix behavior of printf with alt-form octal, zero precision, zero valueRich Felker-1/+1
in this case there are two conflicting rules in play: that an explicit precision of zero with the value zero produces no output, and that the '#' modifier for octal increases the precision sufficiently to yield a leading zero. ISO C (7.19.6.1 paragraph 6 in C99+TC3) includes a parenthetical remark to clarify that the precision-increasing behavior takes precedence, but the corresponding text in POSIX off of which I based the implementation is missing this remark. this issue was covered in WG14 DR#151.
2014-11-05math: use fnstsw consistently instead of fstsw in x87 asmSzabolcs Nagy-11/+11
fnstsw does not wait for pending unmasked x87 floating-point exceptions and it is the same as fstsw when all exceptions are masked which is the only environment libc supports.
2014-11-05math: fix x86_64 and x32 asm not to use sahf instructionSzabolcs Nagy-28/+14
Some early x86_64 cpus (released before 2006) did not support sahf/lahf instructions so they should be avoided (intel manual says they are only supported if CPUID.80000001H:ECX.LAHF-SAHF[bit 0] = 1). The workaround simplifies exp2l and expm1l because fucomip can be used instead of the fucomp;fnstsw;sahf sequence copied from i386. In fmodl and remainderl sahf is replaced by a simple bit test.
2014-11-05fix 64-bit syscall argument passing on or1kRich Felker-1/+1
the kernel syscall interface for or1k does not expect 64-bit arguments to be aligned to "even" register boundaries. this incorrect alignment broke truncate/ftruncate and as well as a few less-common syscalls.
2014-10-31fix uninitialized mode variable in openat functionRich Felker-1/+1
this was introduced in commit 2da3ab1382ca8e39eb1e4428103764a81fba73d3 as an oversight while making the variadic argument access conditional.
2014-10-31math: use the rounding idiom consistentlySzabolcs Nagy-58/+89
the idiomatic rounding of x is n = x + toint - toint; where toint is either 1/EPSILON (x is non-negative) or 1.5/EPSILON (x may be negative and nearest rounding mode is assumed) and EPSILON is according to the evaluation precision (the type of toint is not very important, because single precision float can represent the 1/EPSILON of ieee binary128). in case of FLT_EVAL_METHOD!=0 this avoids a useless store to double or float precision, and the long double code became cleaner with 1/LDBL_EPSILON instead of ifdefs for toint. __rem_pio2f and __rem_pio2 functions slightly changed semantics: on i386 a double-rounding is avoided so close to half-way cases may get evaluated differently eg. as sin(pi/4-eps) instead of cos(pi/4+eps)
2014-10-31fix rint.c and rintf.c when FLT_EVAL_METHOD!=0Szabolcs Nagy-4/+22
The old code used the rounding idiom incorrectly: y = (double)(x + 0x1p52) - 0x1p52; the cast is useless if FLT_EVAL_METHOD==0 and causes a second rounding if FLT_EVAL_METHOD==2 which can give incorrect result in nearest rounding mode, so the correct idiom is to add/sub a power-of-2 according to the characteristics of double_t. This did not cause actual bug because only i386 is affected where rint is implemented in asm. Other rounding functions use a similar idiom, but they give correct results because they only rely on getting a neighboring integer result and the rounding direction is fixed up separately independently of the current rounding mode. However they should be fixed to use the idiom correctly too.
2014-10-30fix invalid access by openat to possibly-missing variadic mode argumentRich Felker-4/+8
the mode argument is only required to be present when the O_CREAT or O_TMPFILE flag is used.
2014-10-30fix failure of open to read variadic mode argument for O_TMPFILERich Felker-1/+1
2014-10-20manually "shrink wrap" fast path in pthread_onceRich Felker-8/+12
this change is a workaround for the inability of current compilers to perform "shrink wrapping" optimizations. in casual testing, it roughly doubled the performance of pthread_once when called on an already-finished once control object.
2014-10-14release 1.1.5v1.1.5Rich Felker-1/+39
2014-10-14suppress macro definitions of ctype functions under C++Rich Felker-0/+7
based on patch by Sergey Dmitrouk.
2014-10-13implement uchar.h (C11 UTF-16/32 conversion) interfacesRich Felker-5/+109
2014-10-13eliminate global waiters count in pthread_onceRich Felker-9/+13
2014-10-10fix missing barrier in pthread_once/call_once shortcut pathRich Felker-2/+6
these functions need to be fast when the init routine has already run, since they may be called very often from code which depends on global initialization having taken place. as such, a fast path bypassing atomic cas on the once control object was used to avoid heavy memory contention. however, on archs with weakly ordered memory, the fast path failed to ensure that the caller actually observes the side effects of the init routine. preliminary performance testing showed that simply removing the fast path was not practical; a performance drop of roughly 85x was observed with 20 threads hammering the same once control on a 24-core machine. so the new explicit barrier operation from atomic.h is used to retain the fast path while ensuring memory visibility. performance may be reduced on some archs where the barrier actually makes a difference, but the previous behavior was unsafe and incorrect on these archs. future improvements to the implementation of a_barrier should reduce the impact.
2014-10-10add explicit barrier operation to internal atomic.h APIRich Felker-6/+33
2014-10-09fix handling of negative offsets in timezone spec stringsRich Felker-10/+7
previously, the hours were considered as a signed quantity while minutes and seconds were always treated as positive offsets. however, semantically the '-' sign should negate the whole hh:mm:ss offset. this bug only affected timezones east of GMT with non-whole-hours offsets, such as those used in India and Nepal.
2014-10-08add new linux file sealing api to fcntl.hSzabolcs Nagy-0/+7
new in linux v3.17 commit 40e041a2c858b3caefc757e26cb85bfceae5062b sealing allows some operations to be blocked on a file which makes file access safer when fds are shared between processes (only supported for shared mem fds currently) flags: F_SEAL_SEAL prevents further sealing F_SEAL_SHRINK prevents file from shrinking F_SEAL_GROW prevents file from growing F_SEAL_WRITE prevents writes fcntl commands: F_GET_SEALS get the current seal flags F_ADD_SEALS add new seal flags
2014-10-08add new IPV6_AUTOFLOWLABEL socket option in netinet/in.hSzabolcs Nagy-0/+1
added in linux v3.17 commit 753a2ad54ef45e3417a9d49537c2b42b04a2e1be enables automatic flow label generation on transmit
2014-10-08add new syscall numbers for seccomp, getrandom, memfd_createSzabolcs Nagy-0/+50
these syscalls are new in linux v3.17 and present on all supported archs except sh. seccomp was added in commit 48dc92b9fc3926844257316e75ba11eb5c742b2c it has operation, flags and pointer arguments (if flags==0 then it is the same as prctl(PR_SET_SECCOMP,...)), the uapi header for flag definitions is linux/seccomp.h getrandom was added in commit c6e9d6f38894798696f23c8084ca7edbf16ee895 it provides an entropy source when open("/dev/urandom",..) would fail, the uapi header for flags is linux/random.h memfd_create was added in commit 9183df25fe7b194563db3fec6dc3202a5855839c it allows anon mmap to have an fd, that can be shared, sealed and needs no mount point, the uapi header for flags is linux/memfd.h
2014-10-08always provide __fpclassifyl and __signbitl definitionsRich Felker-1/+9
previously the external definitions of these functions were omitted on archs where long double is the same as double, since the code paths in the math.h macros which would call them are unreachable. however, even if they are unreachable, the definitions are still mandatory. omitting them is invalid C, and in the case of a non-optimizing compiler, will result in a link error.
2014-10-06ignore access mode bits of flags in mkostemps and functions that use itRich Felker-0/+1
per the text accepted for inclusion in POSIX, behavior is unspecified when any of the access mode bits are set. since it's impossible to consistently report this usage error (O_RDONLY could not be detected since its value happens to be zero), the most consistent way to handle them is just to ignore them. previously, if a caller erroneously passed O_WRONLY, the resulting access mode would be O_WRONLY|O_RDWR, which has the value 3, and this resulted in a file descriptor which rejects both read and write attempts when it is subsequently used.
2014-10-04fix handling of odd lengths in swab functionRich Felker-1/+1
this function is specified to leave the last byte with "unspecified disposition" when the length is odd, so for the most part correct programs should not be calling swab with odd lengths. however, doing so is permitted, and should not write past the end of the destination buffer.
2014-09-22fix incorrect sequence generation in *rand48 prng functionsRich Felker-2/+2
patch by Jens Gustedt. this fixes a bug reported by Nadav Har'El. the underlying issue was that a left-shift by 16 bits after promotion of unsigned short to int caused integer overflow. while some compilers define this overflow case as "shifting into the sign bit", doing so doesn't help; the sign bit then gets extended through the upper bits in subsequent arithmetic as unsigned long long. this patch imposes a promotion to unsigned prior to the shift, so that the result is well-defined and matches the specified behavior.
2014-09-19fix linked list corruption in flockfile listsRich Felker-0/+1
commit 5345c9b884e7c4e73eb2c8bb83b8d0df20f95afb added a linked list to track the FILE streams currently locked (via flockfile) by a thread. due to a failure to fully link newly added members, removal from the list could leave behind references which could later result in writes to already-freed memory and possibly other memory corruption. implicit stdio locking was unaffected; the list is only used in conjunction with explicit flockfile locking. this bug was not present in any releases; it was introduced and fixed during the same release cycle. patch by Timo Teräs, who discovered and tracked down the bug.
2014-09-18math: fix exp10 not to raise invalid exception on NaNSzabolcs Nagy-4/+13
This was not caught earlier because gcc incorrectly generates quiet relational operators that never raise exceptions.
2014-09-16fix overflow corner case in strtoul-family functionsRich Felker-0/+1
incorrect behavior occurred only in cases where the input overflows unsigned long long, not just the (possibly lower) range limit for the result type. in this case, processing of the '-' sign character was not suppressed, and the function returned a value of 1 despite setting errno to ERANGE.
2014-09-13rewrite the regex pattern parser in regcompSzabolcs Nagy-1081/+634
The new code is a bit simpler and the generated code is about 1KB smaller (on i386). The basic design was kept including internal interfaces, TNFA generation was not touched. The old tre parser had various issues: [^aa-z] negated overlapping ranges in a bracket expression were handled incorrectly (eg [^aa-z] was handled as [^a] instead of [^a-z]) a{,2} missing lower bound in a counted repetition should be an error, but it was accepted with broken semantics: a{,2} was treated as a{0,3}, the new parser rejects it a{999,} large min count was not rejected (a{5000,} failed with REG_ESPACE due to reaching a stack limit), the new parser enforces the RE_DUP_MAX limit \xff regcomp used to accept a pattern with illegal sequences in it (treated them as empty expression so p\xffq matched pq) the new parser rejects such patterns with REG_BADPAT or REG_ERANGE [^b-fD-H] with REG_ICASE old parser turned this into [^b-fB-F] because of the negated overlapping range issue (see above), the new parser treats it as [^b-hB-H], POSIX seems to require [^d-fD-F], but practical implementations do case-folding first and negate the character set later instead of the other way around. (Supporting the posix way efficiently would require significant changes so it was left as is, it is unclear if any application actually expects the posix behaviour, this issue is raised on the austingroup tracker: http://austingroupbugs.net/view.php?id=872 ). another case-insensitive matching issue is that unicode case folding rules can group more than two characters together while towupper and towlower can only work for a pair of upper and lower case characters, this is a limitation of POSIX so it is not fixed. invalid bracket and brace expressions may return different error codes now (REG_ERANGE instead of REG_EBRACK or REG_BADBR instead of REG_EBRACE) otherwise the new parser should be compatible with the old one. regcomp should be able to handle arbitrary pattern input if the pattern length is limited, the only exception is the use of large repetition counts (eg. (a{255}){255}) which require exp amount of memory and there is no easy workaround.
2014-09-11fix C++ incompatibility in i386 definition of max_align_tRich Felker-0/+4
the C11 _Alignas keyword is not present in C++, and despite it being in the reserved namespace and thus reasonable to support even in non-C11 modes, compilers seem to fail to support it.
2014-09-10add _DEFAULT_SOURCE feature profile as an alias for _BSD_SOURCERich Felker-0/+4
as a result of commit ab8f6a6e42ff893041f7545a23e6d6a0edde07fb, this definition is now equivalent to the actual "default profile" which appears immediately below in features.h, and which defines both _BSD_SOURCE and _XOPEN_SOURCE. the intent of providing a _DEFAULT_SOURCE, which glibc also now provides, is to give applications a way to "get back" the default feature profile when it was lost either by compiler flags that inhibit it (such as -std=c99) or by library-provided predefined macros (such as -D_POSIX_C_SOURCE=200809L) which may inhibit exposure of features that were otherwise visible by default and which the application may need. without _DEFAULT_SOURCE, the application had encode knowledge of a particular libc's defaults, and such knowledge was fragile and subject to bitrot. eventually the names _GNU_SOURCE and _BSD_SOURCE should be phased out in favor of the more-descriptive and more-accurate _ALL_SOURCE and _DEFAULT_SOURCE, leaving the old names as aliases but using the new ones internally. however this is a more invasive change that would require extensive regression testing, so it is deferred.
2014-09-10fix _ALL_SOURCE logic to avoid possible redefinition of _GNU_SOURCERich Felker-1/+1
this could be an error if _GNU_SOURCE was already defined differently by the application.
2014-09-10fix places where _BSD_SOURCE failed to yield a superset of _XOPEN_SOURCERich Felker-8/+2
the vast majority of these failures seem to have been oversights at the time _BSD_SOURCE was added, or perhaps shortly afterward. the one which may have had some reason behind it is omission of setpgrp from the _BSD_SOURCE feature profile, since the standard setpgrp interface conflicts with a legacy (pre-POSIX) BSD interface by the same name. however, such omission is not aligned with our general policy in this area (for example, handling of similar _GNU_SOURCE cases) and should not be preserved.
2014-09-08fix exp10l.c to include float.hSzabolcs Nagy-0/+1
the previous commit was a no op in exp10l because LDBL_* macros were implicitly 0 (the preprocessor does not warn about undefined symbols).
2014-09-08prune math code on archs with binary64 long doubleSzabolcs Nagy-0/+10
__polevll, __p1evll and exp10l were provided on archs when long double is the same as double. The first two were completely unused and exp10l can be a wrapper around exp10.
2014-09-08add new F_OFD_* macros to fcntl.h (open file description locks)Szabolcs Nagy-0/+4
open file description locks are inherited across fork and only auto dropped after the last fd of the file description is closed, they can be used to synchronize between threads that open separate file descriptions for the same file. new in linux 3.15 commit 0d3f7a2dd2f5cf9642982515e020c1aee2cf7af6
2014-09-07add C11 thread creation and related thread functionsRich Felker-7/+84
based on patch by Jens Gustedt. the main difficulty here is handling the difference between start function signatures and thread return types for C11 threads versus POSIX threads. pointers to void are assumed to be able to represent faithfully all values of int. the function pointer for the thread start function is cast to an incorrect type for passing through pthread_create, but is cast back to its correct type before calling so that the behavior of the call is well-defined. changes to the existing threads implementation were kept minimal to reduce the risk of regressions, and duplication of code that carries implementation-specific assumptions was avoided for ease and safety of future maintenance.
2014-09-06add C11 condition variable functionsJens Gustedt-0/+57
Because of the clear separation for private pthread_cond_t these interfaces are quite simple and direct.
2014-09-06add C11 mutex functionsJens Gustedt-0/+69
2014-09-06add C11 thread functions operating on tss_t and once_flagJens Gustedt-0/+42
These all have POSIX equivalents, but aside from tss_get, they all have minor changes to the signature or return value and thus need to exist as separate functions.
2014-09-06add threads.h and needed per-arch types for mtx_t and cnd_tRich Felker-0/+103
based on patch by Jens Gustedt. mtx_t and cnd_t are defined in such a way that they are formally "compatible types" with pthread_mutex_t and pthread_cond_t, respectively, when accessed from a different translation unit. this makes it possible to implement the C11 functions using the pthread functions (which will dereference them with the pthread types) without having to use the same types, which would necessitate either namespace violations (exposing pthread type names in threads.h) or incompatible changes to the C++ name mangling ABI for the pthread types. for the rest of the types, things are much simpler; using identical types is possible without any namespace considerations.
2014-09-06use weak symbols for the POSIX functions that will be used by C threadsJens Gustedt-29/+76
The intent of this is to avoid name space pollution of the C threads implementation. This has two sides to it. First we have to provide symbols that wouldn't pollute the name space for the C threads implementation. Second we have to clean up some internal uses of POSIX functions such that they don't implicitly drag in such symbols.
2014-09-06add C11 timespec_get function, with associated time.h changes for C11Rich Felker-1/+15
based on patch by Jens Gustedt for inclusion with C11 threads implementation, but committed separately since it's independent of threads.
2014-09-06fix non-static dummy function that slipped in with locale implementationRich Felker-1/+1
2014-09-05fix macros for LFS *64_t types in sys/stat.h, sys/types.h, glob.hSzabolcs Nagy-2/+3
there is no blksize64_t (blksize_t is always long) but there are fsblkcnt64_t and fsfilcnt64_t types in sys/stat.h and sys/types.h. and glob.h missed glob64_t.
2014-09-05add missing legacy LFS *64 symbol aliasesSzabolcs Nagy-0/+23
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.
2014-09-05fix memory leak in regexec when input contains illegal sequenceSzabolcs Nagy-5/+6