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2018-09-12use idiomatic weak alias approach for defining asctime_rRich Felker-33/+28
get rid of a gratuitous translation unit and call frame between asctime_r and the actual implementation of the function. this is the way gmtime_r and localtime_r are already done.
2018-09-12move and deduplicate declarations of __vdsosym to make it checkableRich Felker-4/+2
2018-09-12move and deduplicate declarations of __procfdname to make it checkableRich Felker-16/+5
syscall.h was chosen as the header to declare it, since its intended usage is alongside syscalls as a fallback for operations the direct syscall does not support.
2018-09-12fix issues from public functions defined without declaration visibleRich Felker-2/+22
policy is that all public functions which have a public declaration should be defined in a context where that public declaration is visible, to avoid preventable type mismatches. an audit performed using GCC's -Wmissing-declarations turned up the violations corrected here. in some cases the public header had not been included; in others, a feature test macro needed to make the declaration visible had been omitted. in the case of gethostent and getnetent, the omission seems to have been intentional, as a hack to admit a single stub definition for both functions. this kind of hack is no longer acceptable; it's UB and would not fly with LTO or advanced toolchains. the hack is undone to make exposure of the declarations possible.
2018-09-05remove leftover declarations for removed functions from pthread_impl.hRich Felker-4/+0
2018-09-05define and use internal macros for hidden visibility, weak refsRich Felker-88/+66
this cleans up what had become widespread direct inline use of "GNU C" style attributes directly in the source, and lowers the barrier to increased use of hidden visibility, which will be useful to recovering some of the efficiency lost when the protected visibility hack was dropped in commit dc2f368e565c37728b0d620380b849c3a1ddd78f, especially on archs where the PLT ABI is costly.
2018-09-04fix namespace violation for c11 mutex functionsRich Felker-1/+3
__pthread_mutex_timedlock is used to implement c11 mutex functions, and therefore cannot call pthread_mutex_trylock by name.
2018-09-04in pthread_mutex_timedlock, avoid repeatedly reading mutex type fieldRich Felker-3/+4
compiler cannot cache immutable fields of the mutex object across external calls it can't see, much less across atomics.
2018-09-04in pthread_mutex_trylock, EBUSY out more directly when possibleRich Felker-2/+2
avoid gratuitously setting up and tearing down the robust list pending slot.
2018-09-04implement fexecve in terms of execveat when it existsJoseph C. Sible-0/+5
This lets fexecve work even when /proc isn't mounted.
2018-09-02fix stack-based oob memory clobber in resolver's result sortingRich Felker-1/+1
commit 4f35eb7591031a1e5ef9828f9304361f282f28b9 introduced this bug. it is not present in any released versions. inadvertent use of the & operator on an array into which we're indexing produced arithmetic on the wrong-type pointer, with undefined behavior.
2018-09-01consistently use _NSIG/8 idiom for kernel sigset size in sigactionRich Felker-3/+3
this code in sigaction was the only place where sizeof was being applied to the kernel sigaction's mask member to get the size argument to pass to the kernel. everywhere else, _NSIG/8 is used for this purpose.
2018-09-01always terminate by SIGABRT when abort is calledRich Felker-4/+40
Linux makes this surprisingly difficult, but it can be done. the trick here is using the fact that we control the implementation of sigaction to prevent changing the disposition of SIGABRT to anything but SIG_DFL after abort has tried and failed to terminate the process simply by calling raise(SIGABRT).
2018-09-01optimize raise not to make a syscall for getting tidRich Felker-3/+1
assuming signals are blocked, which they are here, the tid in the thread structure is always valid and cannot change out from under us.
2018-08-30prevent perror from clobbering stderr's orientationRich Felker-0/+8
this requirement is specified by POSIX.
2018-08-30prevent psignal/psiginfo from clobbering stderr orientation, errnoRich Felker-8/+21
these functions are specified to write to stderr but not set its orientation, presumably so that they can be used in programs operating stderr in wide mode. also, they are not allowed to clobber errno on success. save and restore to meet the requirement. psiginfo is reduced to a think wrapper around psignal, since it already behaved the same. if we want to add more detailed siginfo printing at some point this will need refactoring.
2018-08-29make vfprintf set stream orientation even for zero-length outputRich Felker-1/+2
if no output is produced, no underlying fwrite will ever be called, but byte-oriented printf functions are still required to set the orientation of the stream to byte-oriented. call __towrite explicitly if the FILE is not already in write mode.
2018-08-29re-fix vfprintf temporary buffer logicRich Felker-2/+2
commit b5a8b28915aad17b6f49ccacd6d3fef3890844d1 setup the write buffer bound pointers for the temporary buffer manually to fix a buffer overflow issue, but in doing so, caused vfprintf on unbuffered files never to call __towrite, thereby failing to set the stream orientation to byte-oriented, failing to clear any prior read mode, and failing to produce an error when the stream is not writable. revert the inline setup of the bounds pointers and instead zero them, so that the underlying fwrite code will call __towrite to set them up.
2018-08-29fix missing flush of stderr at exit if it was put in buffered modeRich Felker-0/+1
commit 0b80a7b0404b6e49b0b724e3e3fe0ed5af3b08ef added the ability to set application-provided stdio FILE buffers, adding the possibility that stderr might be buffered at exit time, but __stdio_exit did not have code to flush it. this regression was not present in any release.
2018-08-29fix async thread cancellation on sh-fdpicRich Felker-0/+3
if __cp_cancel was reached via __syscall_cp, r12 will necessarily still contain a GOT pointer (for libc.so or for the static-linked main program) valid for entering __cancel. however, in the case of async cancellation, r12 may contain any scratch value; it's not necessarily even a valid GOT pointer for the code that was interrupted. unlike in commit 0ec49dab6794166d67fae4764ce7fdea42ea6103 where the corresponding issue was fixed for powerpc64, there is fundamentally no way for fdpic code to recompute its GOT pointer. so a new mechanism is introduced for cancel_handler to write a GOT register value into the interrupted context on archs where it is needed.
2018-08-29fix async thread cancellation on powerpc64Rich Felker-0/+7
entering the local entry point for __cancel from __cp_cancel is valid if __cp_cancel was reached from __syscall_cp, since both are in libc and share the same TOC pointer, but it is not valid if __cp_cancel was reached when cancel_handler rewrote the program counter for asynchronous cancellation of code outside libc. to ensure __cancel is entered with a valid TOC pointer, recompute the correct value in a PC-relative manner before jumping.
2018-08-28vfwprintf: honor field width with 'c' format typeA. Wilcox-1/+4
2018-08-28fix several values reported by sysconfRich Felker-8/+11
- REALTIME_SIGNALS is supposed to be version-valued - DELAYTIMER_MAX was wrongly using the min allowed max - unavailable compilation environments wrongly used 0 instead of -1
2018-08-28fix return value of system on failure to spawn child processRich Felker-1/+1
the value 0x7f00 (as if by _exit(127)) is specified only for the case where the child is created but then fails to exec the shell, since traditional fork+exec implementations do not admit reporting an error via errno in this case without additional machinery. it's unclear whether an implementation not subject to this failure mode needs to emulate it; one could read the standard as requiring that. if so, additional code will need to be added to map posix_spawn errors into the form system is expected to return. but for now, returning -1 to indicate an error is significantly better behavior than always reporting failures as if the shell failed to exec after fork.
2018-08-28set stream orientations in open_[w]memstreamRich Felker-0/+3
fundamentally there is no good reason these functions need to set an orientation (morally it should be possible to write a wchar_t[] memory stream using byte functions, or a char[] memory stream using wide functions), but it's a part of the specification that they do. aside from being able to inspect the orientation with fwide, failure to set the orientation in open_wmemstream is observable if the locale changes between open_wmemstream and the first operation on the stream; this is because the encoding rule (locale) for the stream is required to be bound at the time the stream becomes wide-oriented. for open_wmemstream, call fwide to avoid duplicating the logic for binding the encoding rule. for open_memstream it suffices just to set the mode field in the FILE struct.
2018-08-28make fmemopen's w+ mode truncate the bufferRich Felker-0/+1
the w+ mode is specified to "truncate the buffer contents". like most of fmemopen, exactly what this means is underspecified. mode w and w+ of course implicitly 'truncate' the buffer if a write from the initial position is flushed, so in order for this part of the text about w+ not to be spurious, it should be interpreted as requiring something else, and the obvious reasonable interpretation is that the truncation is immediately visible if you attempt to read from the stream or the buffer before writing/flushing. this interpretation agrees with reported conformance test failures.
2018-08-28set errno when fileno is called on a FILE with no underlying fdRich Felker-4/+7
this is a POSIX requirement. also remove the gratuitous locking shenanigans and simply access f->fd under control of the lock. there is no advantage to not doing so, and it made the correctness non-obvious at best.
2018-08-28reject invalid arguments to pthread_barrierattr_setpsharedRich Felker-0/+1
this is a POSIX requirement.
2018-08-28rewrite __aeabi_read_tp in asmSzabolcs Nagy-12/+6
__aeabi_read_tp used to call c code, but that was incorrect as the arm runtime abi specifies special pcs for this function: it is only allowed to clobber r0, ip, lr and cpsr. maintainer's note: the old code explicitly saved and restored all general-purpose registers which are call-clobbered in the normal calling convention, so it's unlikely that any real-world compilers produced code that could break. however theoretically they could have chosen to use floating point registers, in which case the caller's values of those registers would be clobbered.
2018-08-28fix deadlock in async thread self-cancellationRich Felker-1/+5
with async cancellation enabled, pthread_cancel(pthread_self()) deadlocked due to pthread_kill holding killlock which is needed by pthread_exit. this could be solved by making pthread_kill block signals around the critical section, at least when the target thread is itself, but the issue only arises for cancellation, and otherwise would just be imposing unnecessary cost. instead just have pthread_cancel explicitly check for async self-cancellation and call pthread_exit(PTHREAD_CANCELED) directly rather than going through the signal machinery.
2018-08-27time: fix incorrect DST offset when using POSIX timezones without DSTA. Wilcox-1/+1
This manifests itself in mktime if tm_isdst = 1 and the current TZ= is a POSIX timezone specification. mktime would see that tm_isdst was set to 0 by __secs_to_zone, and subtract 'oppoff' (dst_off) - gmtoff from the resultant time. This meant that mktime returned a time that was exactly double the GMT offset of the desired timezone when tm_isdst was = 1.
2018-08-23fix tls access on arm targets before armv6kSzabolcs Nagy-1/+1
commit 610c5a8524c3d6cd3ac5a5f1231422e7648a3791 changed the thread pointer setup so tp points at the end of the pthread struct on arm, but failed to update __aeabi_read_tp so it was off by 8. this broke tls access in code that is compiled with -mtp=soft, which is the default when target arch is pre armv6k or thumb1. maintainer's note: no release versions are affected.
2018-08-23fix missing strerror text for EMULTIHOPRich Felker-0/+1
this is an obsolete error code from RFS, an obsolete predecessor of NFS. POSIX documents it only as "Reserved", but maintains the requirement that it be defined. as long as it is defined, it needs a string for strerror to produce; the one chosen matches glibc and documentation from other language runtimes I could find.
2018-08-23fix printf precision specifier for hex floats on non-ld80 archsRich Felker-0/+1
the code to perform rounding to the desired precision wrongly assumed the long double mantissa was an integral number of nibbles (hex digits) in length. this is true for 80-bit extended precision (64-bit mantissa) but not for double (53) or quad (113). scale the rounding value by 1<<(LDBL_MANT_DIG%4) to compensate.
2018-08-22getopt: update optarg and optind correctly on missing argumentRich Felker-6/+6
the text of the specification for getopt's handling of options that require an argument, which requires updating optarg and optind, does not exclude the error case where the end of the argument list has been reached. in that case, it is expected that optarg be assigned argv[argc] (normally null) and optind be incremented by 2, resulting in a value of argc+1.
2018-08-20remove erroneous SYMLINK_MAX definition from limits.h, pathconfRich Felker-1/+1
POSIX requires the symlink function to fail with ENAMETOOLONG if the link contents to be written exceed SYMLINK_MAX in length, but neither Linux nor our syscall wrapper code enforce this. the value 255 for SYMLINK_MAX is not meaningful and does not seem to have been motivated by anything except perhaps a wrong assumption that a definition was mandatory. it has been present (though moving through bits to top-level limits.h) since the beginning of the project history. [f]pathconf is entitled to return -1 as the limit for conf names for which there is no hard limit, with the usual POSIX note that an indefinite limit does not imply an infinite limit. in principle we might should report a limit for filesystems that impose one, but such functionality is not currently present for any of the pathconf limits, and adding it is beyond the scope of fixing the incorrect limit.
2018-08-18mips archs: fix runaway execution if start fn passed to clone returnsSegev Finer-3/+12
Call SYS_exit on return from fn in __clone. This is the expected behavior of this function. Without this the child task will crash on return from fn, since it will return to nowhere.
2018-08-16fix pthread_create return value with PTHREAD_EXPLICIT_SCHEDRich Felker-0/+1
due to moved code, commit b8742f32602add243ee2ce74d804015463726899 inadvertently used the return value of __clone, rather than the return value of SYS_sched_setscheduler in the new thread, to check whether it needed to report failure. since a successful __clone returns the tid of the new thread, which is never zero, this caused pthread_create always to return with an invalid error number in the code path for PTHREAD_EXPLICIT_SCHED. this regression was not present in any releases.
2018-08-07fix sign of strftime %z output with offsets <1 hour west of UTCRich Felker-3/+2
the sign character produced came from the sign of tm_gmtoff/3600 as an integer division, which is zero for negative offsets smaller in magnitude than 3600. instead of printing the hours and minutes as separate fields, print them as a single value of the form hours*100+minutes, which naturally has the correct sign.
2018-07-27make pthread_attr_init honor defaults set by pthread_setattr_default_npRich Felker-4/+11
this fixes a major gap in the intended functionality of pthread_setattr_default_np. if application/library code creating a thread does not pass a null attribute pointer to pthread_create, but sets up an attribute object to change other properties while leaving the stack alone, the created thread will get a stack with size DEFAULT_STACK_SIZE. this makes pthread_setattr_default_np useless for working around stack overflow issues in such applications, and leaves a major risk of regression if previously-working code switches from using a null attribute pointer to an attribute object. this change aligns the behavior more closely with the glibc pthread_setattr_default_np functionality too, albeit via a different mechanism. glibc encodes "default" specially in the attribute object and reads the actual default at thread creation time. with this commit, we now copy the current default into the attribute object at pthread_attr_init time, so that applications that query the properties of the attribute object will see the right values.
2018-07-23bsearch: simplify and optimizeFangrui Song-6/+6
maintainer's note: the key observation here is that the compared element is the first slot of the second ceil(half) of the array, and thus can be removed for further comparison when it does not match, so that we descend into the second ceil(half)-1 rather than ceil(half) elements. this change ensures that nel strictly decreases with each iteration, so that the case of != but nel==1 does not need to be special-cased anymore.
2018-07-18remove spurious declaration of __getdents from readdir.cRich Felker-2/+0
2018-07-18fix regression in alignment of dirent structs produced by readdirRich Felker-1/+7
commit 32482f61da7650ff10741bd5aedd66bbc3ea165b reduced the number of int members before the dirent buf from 4 to 3, thereby misaligning it mod sizeof(off_t), producing invalid accesses on any arch where alignof(off_t)==sizeof(off_t). rather than re-adding wasted padding, reorder the struct to meet the requirement and add a comment and static assertion to prevent this from getting broken again.
2018-07-14implement getaddrinfo's AI_ADDRCONFIG flagRich Felker-0/+39
this flag is notoriously under-/mis-specified, and in the past it was implemented as a nop, essentially considering the absence of a loopback interface with 127.0.0.1 and ::1 addresses an unsupported configuration. however, common real-world container environments omit IPv6 support (even for the network-namespaced loopback interface), and some kernels omit IPv6 support entirely. future systems on the other hand might omit IPv4 entirely. treat these as supported configurations and suppress results of the unconfigured/unsupported address families when AI_ADDRCONFIG is requested. use routability of the loopback address to make the determination; unlike other implementations, we do not exclude loopback from the "an address is configured" condition, since there is no basis in the specification for such exclusion. obtaining a result with AI_ADDRCONFIG does not imply routability of the result, and applications must still be able to cope with unroutable results even if they pass AI_ADDRCONFIG.
2018-07-13fix writes outside buffer by ungetc after setvbufRich Felker-1/+1
commit 0b80a7b0404b6e49b0b724e3e3fe0ed5af3b08ef, which added non-stub setvbuf, applied the UNGET pushback adjustment to the size of the buffer passed in, but inadvertently omitted offsetting the start by the same amount, thereby allowing unget to clobber up to 8 bytes before the start of the buffer. this bug was introduced in the present release cycle; no releases are affected.
2018-07-11resolver: don't depend on v4mapped ipv6 to probe routability of v4 addrsRich Felker-15/+32
to produce sorted results roughly corresponding to RFC 3484/6724, __lookup_name computes routability and choice of source address via dummy UDP connect operations (which do not produce any packets). since at the logical level, the properties fed into the sort key are computed on ipv6 addresses, the code was written to use the v4mapped ipv6 form of ipv4 addresses and share a common code path for them all. however, on kernels where ipv6 support has been completely omitted, this causes ipv4 to appear equally unroutable as ipv6, thereby putting unreachable ipv6 addresses before ipv4 addresses in the results. instead, use only ipv4 sockets to compute routability for ipv4 addresses. some gratuitous conversion back and forth is left so that the logic is not affected by these changes. it may be possible to simplify the ipv4 case considerably, thereby reducing code size and complexity.
2018-07-02optimize explicit_bzero for sizeAlexander Monakov-1/+1
Avoid saving/restoring the incoming argument by reusing memset return value.
2018-06-26fix missing timeout argument to futex syscall in __futexwaitPatrick Oppenlander-2/+2
2018-06-26add explicit_bzero implementationDavid Carlier-0/+8
maintainer's note: past sentiment was that, despite being imperfect and unable to force clearing of all possible copies of sensitive data (e.g. in registers, register spills, signal contexts left on the stack, etc.) this function would be added if major implementations agreed on it, which has happened -- several BSDs and glibc all include it.
2018-06-26inet_ntop: do not compress single zeros in IPv6Arthur Jones-1/+1
maintainer's note: this change is for conformance with RFC 5952, 4.2.2, which explicitly forbids use of :: to shorten a single 16-bit 0 field when producing the canonical text representation for an IPv6 address. fixes a test failure reported by Philip Homburg, who also submitted a patch, but this fix is simpler and should produce smaller code.