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* fix call to __pthread_tsd_run_dtors with too many argumentsRich Felker2019-01-211-1/+1
| | | | | | commit a6054e3c94aa0491d7366e4b05ae0d73f661bfe2 removed the argument, making it a constraint violation to pass one. caught by cparser/firm; other compilers seem to ignore it.
* configure: accept ppc[64] as alias for powerpc[64] in gcc tuplesRich Felker2019-01-191-2/+2
| | | | | apparently some distros use this form, and it seems to be supported in the gcc build system.
* fix unintended linking dependency of pthread_key_create on __synccallRich Felker2019-01-161-0/+6
| | | | | | | | | | | commit 84d061d5a31c9c773e29e1e2b1ffe8cb9557bc58 attempted to do this already, but omitted from pthread_key_create.c the weak definition of __pthread_key_delete_synccall, so that the definition provided by pthread_key_delete.c was always pulled in. based on patch by Markus Wichmann, but with a weak alias rather than weak reference for consistency/policy about dependence on tooling features.
* halt getspnam[_r] search on error accessing TCB shadowRich Felker2018-12-281-0/+2
| | | | | | fallback to /etc/shadow should happen only when the entry is not found in the TCB shadow. otherwise transient errors or permission errors can cause inconsistent results.
* don't set errno or return an error when getspnam[_r] finds no entryRich Felker2018-12-282-3/+9
| | | | | this case is specified as success with a null result, rather than an error, and errno is not to be set on success.
* make sem_wait and sem_timedwait interruptible by signalsRich Felker2018-12-191-1/+1
| | | | | | | | | | | | | | | | | | this reverts commit c0ed5a201b2bdb6d1896064bec0020c9973db0a1, which was based on a mistaken reading of POSIX due to inconsistency between the description (which requires return upon interruption by a signal) and the errors list (which wrongly lists EINTR as "may fail"). since the previously-introduced behavior was a workaround for an old kernel bug to ensure safety of correct programs that were not hardened against the bug, an effort has been made to preserve it for programs which do not use interrupting signal handlers. the stage for this was set in commit a63c0104e496f7ba78b64be3cd299b41e8cd427f, which makes the futex __timedwait backend suppress EINTR if it's seen when no interrupting signal handlers have been installed. based loosely on a patch submitted by Orivej Desh, but with unnecessary additional changes removed.
* don't fail pthread_sigmask/sigprocmask on invalid how when set is nullRich Felker2018-12-181-1/+1
| | | | | | | | the resolution of Austin Group issue #1132 changes the requirement to fail so that it only applies when the set argument (new mask) is non-null. this change was made for consistency with the description, which specified "if set is a null pointer, the value of the argument how is not significant".
* add __timedwait backend workaround for old kernels where futex EINTRsRich Felker2018-12-183-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | prior to linux 2.6.22, futex wait could fail with EINTR even for non-interrupting (SA_RESTART) signals. this was no problem provided the caller simply restarted the wait, but sem_[timed]wait is required by POSIX to return when interrupted by a signal. commit a113434cd68ce30642c4995b1caadcd084be6f09 introduced this behavior, and commit c0ed5a201b2bdb6d1896064bec0020c9973db0a1 reverted it based on a mistaken belief that it was not required. this belief stems from a bug in the specification: the description requires the function to return when interrupted, but the errors section marks EINTR as a "may fail" condition rather than a "shall fail" one. since there does seem to be significant value in the change made in commit c0ed5a201b2bdb6d1896064bec0020c9973db0a1, making it so that programs that call sem_wait without checking for EINTR don't silently make forward progress without obtaining the semaphore or treat it as a fatal error and abort, add a behind-the-scenes mechanism in the __timedwait backend to suppress EINTR in programs that have never installed interrupting signal handlers, and have sigaction track and report this state. this way the semaphore code is not cluttered by workarounds and can be updated (to be done in next commit) to reflect the high-level logic for conforming behavior. these changes are based loosely on a patch by Markus Wichmann, with the main changes being atomic update to flag object and moving the workaround from sem_timedwait to the __timedwait futex backend.
* on failed aio submission, set aiocb error and return valueRich Felker2018-12-111-2/+4
| | | | | | | | it's not clear whether this is required, but it seems arguable that it should happen. for example aio_suspend is supposed to return immediately if any of the operations has "completed", which includes ending with an error status asynchonously and might also be interpreted to include doing so synchronously.
* don't create aio queue/map structures for invalid file descriptorsRich Felker2018-12-111-4/+8
| | | | | | | | | | | | | | the map structures in particular are permanent once created, and thus a large number of aio function calls with invalid file descriptors could exhaust memory, whereas, assuming normal resource limits, only a very small number of entries ever need to be allocated. check validity of the fd before allocating anything new, so that allocation of large amounts of memory is only possible when resource limits have been increased and a large number of files are actually open. this change also improves error reporting for bad file descriptors to happen at the time the aio submission call is made, as opposed to asynchronously.
* move aio queue allocation from io thread to submitting threadRich Felker2018-12-111-16/+21
| | | | | | | | | | | | | | | since commit c9f415d7ea2dace5bf77f6518b6afc36bb7a5732, it has been possible that the allocator is application-provided code, which cannot necessarily run safely on io thread stacks, and which should not be able to see the existence of io threads, since they are an implementation detail. instead of having the io thread request and possibly allocate its queue (and the map structures leading to it), make the submitting thread responsible for this, and pass the queue pointer into the io thread via its args structure. this eliminates the only early error case in io threads, making it no longer necessary to pass an error status back to the submitting thread via the args structure.
* fix and future-proof against stack overflow in aio io threadsRich Felker2018-12-091-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | aio threads not using SIGEV_THREAD notification are created with small stacks and no guard page, which is possible since they only run the code for the requested io operation, not any application code. the motivation is not creating a lot of VMAs. however, the io thread needs to be able to receive a cancellation signal in case aio_cancel (implemented via pthread_cancel) is called. this requires sufficient stack space for a signal frame, which PTHREAD_STACK_MIN does not necessarily include. in principle MINSIGSTKSZ from signal.h should give us sufficient space for a signal frame, but the value is incorrect on some existing archs due to kernel addition of new vector register support without consideration for impact on ABI. some powerpc models exceed MINSIGSTKSZ by about 0.5k, and x86[_64] with AVX-512 can exceed it by up to about 1.5k. so use MINSIGSTKSZ+2048 to allow for the discrepancy plus some working space. unfortunately, it's possible that signal frame sizes could continue to grow, and some archs (aarch64) explicitly specify that they may. passing of a runtime value for MINSIGSTKSZ via AT_MINSIGSTKSZ in the aux vector was added to aarch64 linux, and presumably other archs will use this mechanism to report if they further increase the signal frame size. when AT_MINSIGSTKSZ is present, assume it's correct, so that we only need a small amount of working space in addition to it; in this case just add 512.
* add namespace-safe version of getauxval for internal useRich Felker2018-12-092-1/+13
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* add NT_VMCOREDD to elf.h from linux v4.18Szabolcs Nagy2018-12-091-0/+1
| | | | | used for device driver dump in /proc/vmcore new in linux commit 2724273e8fd00b512596a77ee063f49b25f36507
* add AT_MINSIGSTKSZ to elf.h from linux v4.18Szabolcs Nagy2018-12-091-0/+1
| | | | | | new in linux commit 94b07c1f8c39c6d839df35fa28ffd1785d385897 currently only supported on aarch64
* add io_pgetevents and rseq syscall numbers from linux v4.18Szabolcs Nagy2018-12-0913-0/+23
| | | | | | | | io_pgetevents is new in linux commit 7a074e96dee62586c935c80cecd931431bfdd0be rseq is new in linux commit d7822b1e24f2df5df98c76f0e94a5416349ff759
* add TRAP_UNK si_code to signal.h from linux v4.18Szabolcs Nagy2018-12-091-0/+1
| | | | | used for undiagnosed trap exceptions where linux previously set si_code to 0. new in linux commit db78e6a0a6f9f7d7277965600eeb1a5b3a6f55a8
* add SIGSYS support to sys/signalfd.h from linux v4.18Szabolcs Nagy2018-12-091-1/+5
| | | | | | | new in linux commit 76b7f670730e87974f71df9f6129811e2769666e in struct signalfd_siginfo the pad member is changed to __pad to keep the namespace clean, it's not part of the public api.
* add AF_XDP to sys/socket.h from linux v4.18Szabolcs Nagy2018-12-091-1/+4
| | | | | new address family and related macros were added in linux commit 68e8b849b221b37a78a110a0307717d45e3593a0
* update netinet/udp.h for linux v4.18Szabolcs Nagy2018-12-091-0/+3
| | | | | | | add UDP_NO_CHECK6_* to restrict zero UDP6 checksums, new in linux commit 1c19448c9ba6545b80ded18488a64a7f3d8e6998 (pre-v4.18 change, was missed) add UDP_SEGMENT to support generic segmentation offload for udp datagrams, bec1f6f697362c5bc635dacd7ac8499d0a10a4e7 (new in v4.18)
* update netinet/tcp.h for linux v4.18Szabolcs Nagy2018-12-091-0/+18
| | | | | | | | | | | add packet delivery info to tcp_info, new in linux commit feb5f2ec646483fb66f9ad7218b1aad2a93a2a5c add TCP_ZEROCOPY_RECEIVE socket option for zerocopy receive, new in linux commit 05255b823a6173525587f29c4e8f1ca33fd7677d add TCP_INQ socket option and TCP_CM_INQ cmsg to get in-queue bytes in cmsg upon read, new in linux commit b75eba76d3d72e2374fac999926dafef2997edd2 add TCP_REPAIR_* to fix repair socket window probe patch, new in linux commit 31048d7aedf31bf0f69c54a662944632f29d82f2
* fix wordexp not to read past end of string ending with lone backslashRich Felker2018-12-091-1/+1
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* fix memccpy to not access buffer past given sizeQuentin Rameau2018-12-021-1/+1
| | | | | memccpy would return a pointer over the given size when c is not found in the source buffer and n reaches 0.
* fix regression in access to optopt objectRich Felker2018-11-191-0/+1
| | | | | | | | commit b9410061e2ad6fe91bb3910c3adc7d4a315b7ce9 inadvertently omitted optopt from the "dynamic list", causing it to be split into separate objects that don't share their value if the main program contains a copy relocation for it (for non-PIE executables that access it, and some PIE ones, depending on arch and toolchain versions/options).
* optimize two-way strstr and memmem bad character shiftRich Felker2018-11-082-2/+2
| | | | | | | | | | | | | | | | first, the condition (mem && k < p) is redundant, because mem being nonzero implies the needle is periodic with period exactly p, in which case any byte that appears in the needle must appear in the last p bytes of the needle, bounding the shift (k) by p. second, the whole point of replacing the shift k by mem (=l-p) is to prevent shifting by less than mem when discarding the memory on shift, in which case linear time could not be guaranteed. but as written, the check also replaced shifts greater than mem by mem, reducing the benefit of the shift. there is no possible benefit to this reduction of the shift; since mem is being cleared, the full shift is valid and more optimal. so only replace the shift by mem when it would be less than mem.
* fix regression in setlocale for LC_ALL with per-category settingRich Felker2018-11-021-1/+1
| | | | | | commit d88e5dfa8b989dafff4b748bfb3cba3512c8482e inadvertently changed the argument pased to __get_locale from part (the current ;-delimited component) to name (the full string).
* fix failure to flush stderr when fflush(0) is calledRich Felker2018-11-021-1/+4
| | | | | | | | commit ddc947eda311331959c73dbc4491afcfe2326346 fixed the corresponding bug for exit which was introduced when commit 0b80a7b0404b6e49b0b724e3e3fe0ed5af3b08ef added support for caller-provided buffers, making it possible for stderr to be a buffered stream.
* fix deadlock and buffered data loss race in fcloseRich Felker2018-11-021-13/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | fflush(NULL) and __stdio_exit lock individual FILEs while holding the open file list lock to walk the list. since fclose first locked the FILE to be closed, then the ofl lock, it could deadlock with these functions. also, because fclose removed the FILE to be closed from the open file list before flushing and closing it, a concurrent fclose or exit could complete successfully before fclose flushed the FILE it was closing, resulting in data loss. reorder the body of fclose to first flush and close the file, then remove it from the open file list only after unlocking it. this creates a window where consumers of the open file list can see dead FILE objects, but in the absence of undefined behavior on the part of the application, such objects will be in an inactive-buffer state and processing them will have no side effects. __unlist_locked_file is also moved so that it's performed only for non-permanent files. this change is not necessary, but preserves consistency (and thereby provides safety/hardening) in the case where an application uses one of the standard streams after closing it while holding an explicit lock on it. such usage is of course undefined behavior.
* __libc_start_main: slightly simplify stage2 pointer setupAlexander Monakov2018-11-021-3/+4
| | | | | | Use "+r" in the asm instead of implementing a non-transparent copy by applying "0" constraint to the source value. Introduce a typedef for the function type to avoid spelling it out twice.
* remove commented-out debug printf from strstrRich Felker2018-11-021-1/+0
| | | | this was leftover from before the initial commit.
* fix spuriously slow check in twoway strstr/memmem coresRich Felker2018-11-022-2/+2
| | | | | mem0 && mem && ... is redundant since mem can only be nonzero when mem0 is nonzero.
* don't omit setting errno in internal __map_file functionRich Felker2018-10-221-2/+2
| | | | | | a caller needs the reason for open (or fstat, albeit unlikely) failure if it's going to make decisions about continuing a path search or similar.
* make the default locale (& a variant) failure-free cases for newlocaleRich Felker2018-10-221-1/+20
| | | | | | | | | | | | | | | commit aeeac9ca5490d7d90fe061ab72da446c01ddf746 introduced fail-safe invariants that creating a locale_t object for the C locale or C.UTF-8 locale will always succeed. extend the guarantee to also cover the following: - newlocale(LC_ALL_MASK, "", 0) - newlocale(LC_ALL_MASK-LC_CTYPE_MASK, "C", 0) provided that the LANG/LC_* environment variables have not been changed by the program. these usages are idiomatic for getting the default locale, and for getting a locale that behaves as the C locale except for honoring the default locale's character encoding.
* simplify newlocale and allow failure for explicit locale namesRich Felker2018-10-221-23/+14
| | | | | | | | | | | | unify the code paths for allocated and non-allocated locale objects, always using a tmp object. this is necessary to avoid clobbering the base locale object too soon if we allow for the possibility that looking up an explicitly requested locale name may fail, and makes the code simpler and cleaner anyway. eliminate the complex and fragile logic for checking whether one of the non-allocated locale objects can be used for the result, and instead just memcmp against each of them.
* remove volatile qualification from category pointers in __locale_structRich Felker2018-10-201-1/+1
| | | | | | | | | | commit 63c188ec42e76ff768e81f6b65b11c68fc43351e missed making this change when switching from atomics to locking for modification of the global locale, leaving access to locale structures unnecessarily burdened with the restrictions of volatile. the volatile qualification was originally added in commit 56fbaa3bbe73f12af2bfbbcf2adb196e6f9fe264.
* adapt setlocale to support possibility of failureRich Felker2018-10-202-12/+22
| | | | | | | introduce a new LOC_MAP_FAILED sentinel for errors, since null pointers for a category's locale map indicate the C locale. at this time, __get_locale does not fail, so there should be no functional change by this commit.
* adjust types in FILE struct to make line buffering check less expensiveRich Felker2018-10-181-4/+2
| | | | | | | | | | | | | | | | | the choice of signed char for lbf was a theoretically space-saving hack that was not helping, and was unwantedly expensive. while comparing bytes against a byte-sized member sounds easy, the trick here was that the byte to be compared was unsigned while the lbf member was signed, making it possible to set lbf negative to disable line buffering. however, this imposed a requirement to promote both operands, zero-extending one and sign-extending the other, in order to compare them. to fix this, repurpose the waiters count slot (unused since commit c21f750727515602a9e84f2a190ee8a0a2aeb2a1). while we're at it, switch mode (orientation) from signed char to int as well. this makes no semantic difference (its only possible values are -1, 0, and 1) but it might help on archs where byte access is awkward.
* optimize internal putc_unlocked macro used in putcRich Felker2018-10-181-1/+2
| | | | | | | | to check whether flush due to line buffering is needed, the int-type character argument must be truncated to unsigned char for comparison. if the original value is subsequently passed to __overflow, it must be preserved, adding to register pressure. since it doesn't matter, truncate all uses so the original value is no longer live.
* fix wrong result for putc variants due to operator precedenceRich Felker2018-10-181-1/+1
| | | | | | | the internal putc_unlocked macro was wrongly returning a meaningless boolean result rather than the written character or EOF. bug was found by reading (very surprising) asm.
* further optimize getc/putc when locking is neededRich Felker2018-10-182-10/+10
| | | | | | | | | | | | | | | check whether the lock is free before loading the calling thread's tid. if so, just use a dummy tid value that cannot compare equal to any actual thread id (because it's one bit wider). this also avoids the need to save the tid and pass it to locking_getc or locking_putc, reducing register pressure. this change might slightly hurt the case where the caller already holds the lock, but it does not affect the single-threaded case, and may significantly improve the multi-threaded case, especially on archs where loading the thread pointer is disproportionately expensive like early mips and arm ISA levels. but even on i386 it helps, at least on some machines; I measured roughly a 10-15% improvement.
* use prototype for function pointer in static link libc init barrierRich Felker2018-10-181-1/+1
| | | | | | this is not needed for correctness, but doesn't hurt, and in some cases the compiler may pessimize the call assuming the callee might be variadic when it lacks a prototype.
* fix error in constraints for static link libc init barrierRich Felker2018-10-181-1/+1
| | | | | | | commit 4390383b32250a941ec616e8bff6f568a801b1c0 inadvertently used "r" instead of "0" for the input constraint, which only happened to work for the configuration I tested it on because it usually makes sense for the compiler to choose the same input and output register.
* fix build regression due to missing file for putc changesRich Felker2018-10-181-0/+22
| | | | | commit d664061adb4d7f6647ab2059bc351daa394bf5da inadvertently omitted the new file putc.h.
* bypass indirection through pointer objects to access stdin/out/errRich Felker2018-10-184-9/+33
| | | | | | | | | | | | | | | | | by ABI, the public stdin/out/err macros use extern pointer objects, and this is necessary to avoid copy relocations that would be expensive and make the size of the FILE structure part of the ABI. however, internally it makes sense to access the underlying FILE objects directly. this avoids both an indirection through the GOT to find the address of the stdin/out/err pointer objects (which can't be computed PC-relative because they may have been moved to the main program by copy relocations) and an indirection through the resulting pointer object. in most places this is just a minor optimization, but in the case of getchar and putchar (and the unlocked versions thereof), ipa constant propagation makes all accesses to members of stdin/out PC-relative or GOT-relative, possibly reducing register pressure as well.
* optimize hot paths of putc with manual shrink-wrappingRich Felker2018-10-173-13/+8
| | | | | this is the analog of commit dd8f02b7dce53d6b1c4282439f1636a2d63bee01, but for putc.
* optimize hot paths of getc with manual shrink-wrappingRich Felker2018-10-174-15/+30
| | | | | | | | | | | | | | | | | | | | | | | | with these changes, in a program that has not created any threads besides the main thread and that has not called f[try]lockfile, getc performs indistinguishably from getc_unlocked. this was measured on several i386 and x86_64 models, and should hold on other archs too simply by the properties of the code generation. the case where the caller already holds the lock (via flockfile) is improved significantly as well (40-60% reduction in time on machines tested) and the case where locking is needed is improved somewhat (roughly 10%). the key technique used here is forcing the non-hot path out-of-line and enabling it to be a tail call. a static noinline function (conditional on __GNUC__) is used rather than the extern hiddens used elsewhere for this purpose, so that the compiler can choose non-default calling conventions, making it possible to tail-call to a callee that takes more arguments than the caller on archs where arguments are passed on the stack or must have space reserved on the stack for spilling the. the tid could just be reloaded via the thread pointer in locking_getc, but that would be ridiculously expensive on some archs where thread pointer load requires a trap or syscall.
* document and make explicit desired noinline property for __init_libcRich Felker2018-10-171-0/+6
| | | | | | | | | | | | | on multiple occasions I've started to flatten/inline the code in __init_libc, only to rediscover the reason it was not inlined: GCC fails to deallocate its stack (and now, with the changes in commit 4390383b32250a941ec616e8bff6f568a801b1c0, fails to produce a tail call to the stage 2 function; see PR #87639) before calling main if it was inlined. document this with a comment and use an explicit noinline attribute if __GNUC__ is defined so that even with CFLAGS that heavily favor inlining it won't get inlined.
* impose barrier between thread pointer setup and use for static linkingRich Felker2018-10-171-0/+13
| | | | | | | | | | | | this is the analog of commit 1c84c99913bf1cd47b866ed31e665848a0da84a2 for static linking. unlike with dynamic linking, we don't have symbolic lookup to use as a barrier. use a dummy (target-agnostic) degenerate inline asm fragment instead. this technique has precedent in commit 05ac345f895098657cf44d419b5d572161ebaf43 where it's used for explicit_bzero. if it proves problematic in any way, loading the address of the stage 2 function from a pointer object whose address leaks to kernelspace during thread pointer init could be used as an even stronger barrier.
* make thread-pointer-loading asm non-volatileRich Felker2018-10-1614-19/+19
| | | | | | | | | | this will allow the compiler to cache and reuse the result, meaning we no longer have to take care not to load it more than once for the sake of archs where the load may be expensive. depends on commit 1c84c99913bf1cd47b866ed31e665848a0da84a2 for correctness, since otherwise the compiler could hoist loads during stage 3 of dynamic linking before the initial thread-pointer setup.
* remove ancient clang workaround from powerpc pthread_arch.h asmRich Felker2018-10-161-5/+0
| | | | | versions of clang all the way back to 3.1 lack the bug this was purportedly working around.
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