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* fix null pointer subtraction and comparison in stdioRich Felker2018-09-1614-31/+41
| | | | | | | | | | | | | | | | | | | | morally, for null pointers a and b, a-b, a<b, and a>b should all be defined as 0; however, C does not define any of them. the stdio implementation makes heavy use of such pointer comparison and subtraction for buffer logic, and also uses null pos/base/end pointers to indicate that the FILE is not in the corresponding (read or write) mode ready for accesses through the buffer. all of the comparisons are fixed trivially by using != in place of the relational operators, since the opposite relation (e.g. pos>end) is logically impossible. the subtractions have been reviewed to check that they are conditional the stream being in the appropriate reading- or writing-through-buffer mode, with checks added where needed. in fgets and getdelim, the checks added should improve performance for unbuffered streams by avoiding a do-nothing call to memchr, and should be negligible for buffered streams.
* fix failure of getdelim to set stream orientation on errorRich Felker2018-09-161-0/+2
| | | | | if EINVAL or ENOMEM happened before the first getc_unlocked, it was possible that the stream orientation had not yet been set.
* check for kernel support before allowing robust mutex creationRich Felker2018-09-151-1/+17
| | | | | | | | | | | | | | | | on some archs, linux support for futex operations (including robust_list processing) that depend on kernelspace CAS is conditional on a runtime check. as of linux 4.18, this check fails unconditionally on nommu archs that perform it, and spurious failure on powerpc64 was observed but not explained. it's also possible that futex support is omitted entirely, or that the kernel is older than 2.6.17. for most futex ops, ENOSYS does not yield hard breakage; userspace will just spin at 100% cpu load. but for robust mutexes, correct behavior depends on the kernel functionality. use the get_robust_list syscall to probe for support at the first call to pthread_mutexattr_setrobust, and block creation of robust mutexes with a reportable error if they can't be supported.
* always reset DST rules during tzsetBenjamin Peterson2018-09-151-1/+2
| | | | | do_tzset() did't always reset the DST transition rules r0 and r1. That means the rules from older TZ settings could leak into newer ones.
* fix undefined behavior in strto* via FILE buffer pointer abuseRich Felker2018-09-154-20/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | in order to produce FILE objects to pass to the intscan/floatscan backends without any (prohibitively costly) extra buffering layer, the strto* functions set the FILE's rend (read end) buffer pointer to an invalid value at the end of the address space, or SIZE_MAX/2 past the beginning of the string. this led to undefined behavior comparing and subtracting the end pointer with the buffer position pointer (rpos). the comparison issue is easily eliminated by using != instead of <. however the subtractions require nontrivial changes: previously, f->shcnt stored the count that would have been read if consuming the whole buffer, which required an end pointer for the buffer. the purpose for this was that it allowed reading it and adding rpos-rend at any time to get the actual count so far, and required no adjustment at the time of __shgetc (actual function call) since the call would only happen when reaching the end of the buffer. to get rid of the dependency on rend, instead offset shcnt by buf-rpos (start of buffer) at the time of last __shlim/__shgetc call. this makes for slightly more work in __shgetc the function, but for the inline macro it's still just as easy to compute the current count. since the scan helper interfaces used here are a big hack, comments are added to document their contracts and what's going on with their implementations.
* improve error handling of ttyname_r and isattyBenjamin Peterson2018-09-152-2/+6
| | | | | | | | | POSIX allows ttyname(_r) and isatty to return EBADF if passed file descriptor is invalid. maintainer's note: these are optional ("may fail") errors, but it's non-conforming for ttyname_r to return ENOTTY when it failed for a different reason.
* add hidden version of &errno accessor functionRich Felker2018-09-142-0/+13
| | | | | | | | | | | this significantly improves codegen in functions that need to access errno but otherwise have no need for a GOT pointer. we could probably improve it much more by including an inline version of the &errno accessor function, but that depends on having the definitions of struct __pthread and __pthread_self(), which at present would expose a lot more than is appropriate. moving them to a small tls.h later might make this more reasonable.
* fix build regression in sysconf for archs with variable page sizeRich Felker2018-09-141-0/+1
| | | | | | commit 5ce3737931bb411a8d167356d4d0287b53b0cbdc removed the inclusion of libc.h from this file as spurious, but it's needed to get PAGE_SIZE on archs where PAGE_SIZE is not a constant defined by limits.h.
* drop lazy plural forms init in dcngettextRich Felker2018-09-141-18/+17
| | | | | | | | | | | there is no good reason to wait to find and process the plural rules for a translated message file until a gettext form requesting plural rule processing is used. it just imposes additional synchronization, here in the form of clunky use of atomics. it looks like there may also have been a race condition where nplurals could be seen without plural_rule being seen, possibly leading to null pointer dereference. if so, this commit fixes it.
* fix regression with compilers not incorporating C99 DR#289 resolutionRich Felker2018-09-131-1/+1
| | | | | | | | | as originally published, the C99 syntax only allowed static index parameter declarators when a gratuitous parameter name was included. gcc 3, which some projects use for bootstrapping, is a supported C99 compiler, but does not have the fix to the standard incorporated, so edit the affected declaration to conform to the earlier buggy C99 syntax.
* wireup linux/name_to_handle_at and name_to_handle_at syscallsKhem Raj2018-09-122-0/+18
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* remove vis.h protected-visibility hackRich Felker2018-09-121-27/+0
| | | | | | | | | since commit dc2f368e565c37728b0d620380b849c3a1ddd78f this has been disabled by default, but was left available in case users unhappy with the resulting size or performance regressions wanted to try to make it work. now that we make widespread use of hidden visibility for internal interfaces, this no longer makes sense. if any costly calls remain they can be fixed with hidden aliases.
* split internal lock API out of libc.h, creating lock.hRich Felker2018-09-1225-17/+32
| | | | | | | | | this further reduces the number of source files which need to include libc.h and thereby be potentially exposed to libc global state and internals. this will also facilitate further improvements like adding an inline fast-path, if we want to do so later.
* move misplaced __fork_handler declarationRich Felker2018-09-122-1/+1
| | | | | | | | pthread_atfork.c does not actually include pthread_impl.h and has no reason to, so it wasn't getting the declaration. move it to libc.h which is already included by both fork.c and pthread_atfork.c. this makes more sense anyway since the function has little to do with pthreads anyway aside from the name.
* remove spurious inclusion of libc.h for LFS64 ABI aliasesRich Felker2018-09-1248-107/+59
| | | | | | the LFS64 macro was not self-documenting and barely saved any characters. simply use weak_alias directly so that it's clear what's being done, and doesn't depend on a header to provide a strange macro.
* reduce spurious inclusion of libc.hRich Felker2018-09-12193-177/+43
| | | | | | | | | | | | | | | | | | | | | libc.h was intended to be a header for access to global libc state and related interfaces, but ended up included all over the place because it was the way to get the weak_alias macro. most of the inclusions removed here are places where weak_alias was needed. a few were recently introduced for hidden. some go all the way back to when libc.h defined CANCELPT_BEGIN and _END, and all (wrongly implemented) cancellation points had to include it. remaining spurious users are mostly callers of the LOCK/UNLOCK macros and files that use the LFS64 macro to define the awful *64 aliases. in a few places, new inclusion of libc.h is added because several internal headers no longer implicitly include libc.h. declarations for __lockfile and __unlockfile are moved from libc.h to stdio_impl.h so that the latter does not need libc.h. putting them in libc.h made no sense at all, since the macros in stdio_impl.h are needed to use them correctly anyway.
* use wrapper headers to hide most namespaced/internally-public symbolsRich Felker2018-09-1212-60/+64
| | | | | | | | | | not all prefixed symbols can be made hidden. some are part of ABI-compat (e.g. __nl_langinfo_l) and others are ABI as a consequence of the way copy relocations for weak aliases work in ELF shared libraries. most, however, can be made hidden. with this commit, there should be no remaining unintentionally visible symbols exported from libc.so.
* remove __vfork aliasRich Felker2018-09-127-28/+7
| | | | | | | this was added so that posix_spawn and possibly other functionality could be implemented in terms of vfork, but that turned out to be unsafe. any such usage needs __clone with proper handling of stack lifetime.
* hide purely dependency-triggering functions in stdio __toread & __towriteRich Felker2018-09-122-2/+2
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* declare __env_rm_add in wrapper stdlib.hRich Felker2018-09-121-0/+1
| | | | | this is perhaps not the ideal place, but no better alternatives stand out.
* hide dependency-triggering pointer object in malloc_usable_size.cRich Felker2018-09-121-2/+2
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* rework malloc_usable_size to use malloc_impl.hRich Felker2018-09-121-9/+1
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* remove unused __futex function and source fileRich Felker2018-09-122-9/+0
| | | | | | | the direct syscall or various thin and mostly-inline wrappers around it are used instead internally. at some point a public futex function should be added, but it's not yet clear what the signature should be, and in the mean time this file is not useful.
* hide __pthread_once_full symbolRich Felker2018-09-121-1/+1
| | | | | | | | | this is a special case that does not need a declaration, because it's not even a libc-internal interface between translation units. instead it's a poor hack around compilers' inability to shrink-wrap critical code paths. after vis.h was disabled, it became more of a pessimization on many archs due to the extra layer of machinery to support a call through the PLT, but now it should be efficient again.
* declare and make hidden additional internal init/exit symbolsRich Felker2018-09-121-0/+4
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* declare and make hidden additional internal stdio symbolsRich Felker2018-09-121-0/+5
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* move declaration and apply hidden visibility to __utc stringRich Felker2018-09-123-4/+1
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* declare and make hidden more internal locale functionsRich Felker2018-09-121-0/+2
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* remove unused __getdents, rename and move fileRich Felker2018-09-121-4/+1
| | | | | | the __-prefixed filename does not make sense when the only purpose of this file is implementing a public function that's not used as a backend for implementing the standard dirent functions.
* remove or make static various unused __-prefixed symbolsRich Felker2018-09-128-17/+10
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* move additional pthread internal declarations to pthread_impl.h, hideRich Felker2018-09-122-2/+15
| | | | these were overlooked for various reasons in earlier stages.
* apply hidden visibility to various remaining internal interfacesRich Felker2018-09-1216-46/+52
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* apply hidden visibility to sigreturn code fragmentsRich Felker2018-09-1215-3/+31
| | | | | | | these were overlooked in the declarations overhaul work because they are not properly declared, and the current framework even allows their declared types to vary by arch. at some point this should be cleaned up, but I'm not sure what the right way would be.
* apply hidden visibility to pthread internalsRich Felker2018-09-121-11/+11
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* apply hidden visibility to stdio internalsRich Felker2018-09-121-26/+26
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* apply hidden visibility to internal time[zone] implementation functionsRich Felker2018-09-121-8/+8
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* apply hidden visibility to internal math functionsRich Felker2018-09-122-26/+26
| | | | | | | | this makes significant differences to codegen on archs with an expensive PLT-calling ABI; on i386 and gcc 7.3 for example, the sin and sinf functions no longer touch call-saved registers or the stack except for pushing outgoing arguments. performance is likely improved too, but no measurements were taken.
* overhaul internally-public declarations using wrapper headersRich Felker2018-09-1290-189/+199
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commits leading up to this one have moved the vast majority of libc-internal interface declarations to appropriate internal headers, allowing them to be type-checked and setting the stage to limit their visibility. the ones that have not yet been moved are mostly namespace-protected aliases for standard/public interfaces, which exist to facilitate implementing plain C functions in terms of POSIX functionality, or C or POSIX functionality in terms of extensions that are not standardized. some don't quite fit this description, but are "internally public" interfacs between subsystems of libc. rather than create a number of newly-named headers to declare these functions, and having to add explicit include directives for them to every source file where they're needed, I have introduced a method of wrapping the corresponding public headers. parallel to the public headers in $(srcdir)/include, we now have wrappers in $(srcdir)/src/include that come earlier in the include path order. they include the public header they're wrapping, then add declarations for namespace-protected versions of the same interfaces and any "internally public" interfaces for the subsystem they correspond to. along these lines, the wrapper for features.h is now responsible for the definition of the hidden, weak, and weak_alias macros. this means source files will no longer need to include any special headers to access these features. over time, it is my expectation that the scope of what is "internally public" will expand, reducing the number of source files which need to include *_impl.h and related headers down to those which are actually implementing the corresponding subsystems, not just using them.
* declare __getopt_msg in stdio_impl.hRich Felker2018-09-122-2/+3
| | | | | | it's not ideal, but the function is essentially an extended stdio function specialized to getopt's needs. the only reason it exists is avoiding pulling printf code into every program using getopt.
* use lighter internal stdio lock in getopt error printingRich Felker2018-09-121-2/+3
| | | | | | the public flockfile interface is significantly heavier because it has to handle the possibility of caller returning or thread exiting while holding the lock.
* add crypt_des header for declarations shared with encrypt functionRich Felker2018-09-123-12/+16
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* make mkostemps source file include the header for its declarationRich Felker2018-09-121-0/+1
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* move __memalign declaration to malloc_impl.hRich Felker2018-09-123-4/+4
| | | | | | | | the malloc-implementation-private header is the only right place for this, because, being in the reserved namespace, __memalign is not interposable and thus not valid to use anywhere else. anything outside of the malloc implementation must call an appropriate-namespace public function (aligned_alloc or posix_memalign).
* use hidden visibility for sh __unmapself backendsRich Felker2018-09-122-2/+3
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* rework mechanism for posix_spawnp calling posix_spawnRich Felker2018-09-122-19/+9
| | | | | | | | | | | | | | | | | | previously, a common __posix_spawnx backend was used that accepted an additional argument for the execve variant to call in the child. this moderately bloated up the posix_spawn function, shuffling arguments between stack and/or registers to call a 7-argument function from a 6-argument one. instead, tuck the exec function pointer in an unused part of the (large) pthread_spawnattr_t structure, and have posix_spawnp duplicate the attributes and fill in a pointer to __execvpe. the net code size change is minimal, but the weight is shifted to the "heavier" function which already pulls in more dependencies. as a bonus, we get rid of an external symbol (__posix_spawnx) that had no really good place for a declaration because it shouldn't have existed to begin with.
* make arch __fesetround backends hiddenRich Felker2018-09-1214-4/+18
| | | | | these are not public interfaces and do not match the public function, but delegate argument checking to it.
* make arch __set_thread_area backends hiddenRich Felker2018-09-1210-1/+10
| | | | | | | | this is not a public interface, and does not even necessarily match the syscall on all archs that have a syscall by that name. on archs where it's implemented in C, no action on the source file is needed; the hidden declaration in pthread_arch.h suffices.
* make arch __clone backends hiddenRich Felker2018-09-1216-1/+16
| | | | | these are not a public interface and are not intended to be callable from anywhere but the public clone function or other places in libc.
* move tlsdesc and internal dl function declarations to dynlink.hRich Felker2018-09-128-16/+17
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* add internal header for declaring __pleval function (used by gettext)Rich Felker2018-09-123-1/+8
| | | | | locale_impl.h could have been used, but this function is completely independent of anything else, and preserving that property seems nice.