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2020-10-30fix missing-wake regression in pthread_cond_waitRich Felker-0/+5
the reasoning in commit 2d0bbe6c788938d1332609c014eeebc1dff966ac was not entirely correct. while it's true that setting the waiters flag ensures that the next unlock will perform a wake, it's possible that the wake is consumed by a mutex waiter that has no relationship with the condvar wait queue being processed, which then takes the mutex. when that thread subsequently unlocks, it sees no waiters, and leaves the rest of the condvar queue stuck. bring back the waiter count adjustment, but skip it for PI mutexes, for which a successful lock-after-waiting always sets the waiters bit. if future changes are made to bring this same waiters-bit contract to all lock types, this can be reverted.
2020-10-28add support for SIGEV_THREAD_ID timersJames Y Knight-5/+19
This is like SIGEV_SIGNAL, but targeted to a particular thread's tid, rather than the process.
2020-10-28fix sem_close unmapping of still-referenced semaphoreRich Felker-3/+5
sem_open is required to return the same sem_t pointer for all references to the same named semaphore when it's opened more than once in the same process. thus we keep a table of all the mapped semaphores and their reference counts. the code path for sem_close checked the reference count, but then proceeded to unmap the semaphore regardless of whether the count had reached zero. add an immediate unlock-and-return for the nonzero refcnt case so the property of performing the munmap syscall after releasing the lock can be preserved.
2020-10-27refactor setxid return path to use __syscall_retRich Felker-14/+9
this avoids some spurious negation and duplicated errno logic, and brings the code in line with the newly-added multithreaded setgroups.
2020-10-27ldso: notify the debugger when we're doing a dlopenrcombs-2/+6
Otherwise lldb doesn't notice the new library and stack traces containing it get cut off unhelpfully.
2020-10-27fix setgroups behavior in multithreaded processRich Felker-1/+29
this function is outside the scope of the standards, but logically should behave like the set*id functions whose effects are process-global.
2020-10-27avoid __synccall for setrlimit on kernels with prlimit syscallRich Felker-20/+17
resource limits have been process-wide since linux 2.6.10, and the prlimit syscall was added in 2.6.36, so prlimit can be assumed to set the resource limits correctly for the whole process.
2020-10-26fix reintroduction of errno clobbering by atfork handlersRich Felker-0/+3
commit bd153422f28634bb6e53f13f80beb8289d405267 reintroduced the bug fixed in c21051e90cd27a0b26be0ac66950b7396a156ba1 by refactoring the __syscall_ret into _Fork where it once again runs before the atfork handlers are called. since _Fork is a public interface that sets errno, this can't be fixed the way it was fixed last time without making new internal interfaces. instead, just save errno, and restore it only on error to ensure that a value of 0 is never restored.
2020-10-26fix pthread_cond_wait paired with with priority-inheritance mutexRich Felker-6/+5
pthread_cond_wait arranged for requeued waiters to wake when the mutex is unlocked by temporarily adjusting the mutex's waiter count. commit 54ca677983d47529bab8752315ac1a2b49888870 broke this when introducing PI mutexes by repurposing the waiter count field of the mutex structure. since then, for PI mutexes, the waiter count adjustment was misinterpreted by the mutex locking code as indicating that the mutex is non a non-recoverable state. it would be possible to special-case PI mutexes here, but instead just drop all adjustment of the waiters count, and instead use the lock word waiters bit for all mutex types. since the mutex is either held by the caller or in unrecoverable state at the time the bit is set, it will necessarily still be set at the time of any subsequent valid unlock operation, and this will produce the desired effect of waking the next waiter. if waiter counts are entirely dropped at some point in the future this code should still work without modification.
2020-10-24lift sigaction abort locking to fix posix_spawn child deadlockRich Felker-13/+16
commit 25ea9f712c30c32957de493d4711ee39d0bbb024 introduced a deadlock to the posix_spawn child whereby, if abort was called in the parent and ended up taking the abort lock to terminate the process, the __libc_sigaction calls in the child would wait forever to obtain a lock that would not be released. this could be fixed by having abort set the abort lock as the exit futex address, but it's cleaner to just remove the SIGABRT special handling from the internal __libc_sigaction and lift it to the public sigaction function. nothing but the posix_spawn child calls __libc_sigaction on SIGABRT, and since commit b7bc966522d73e1dc420b5ee6fc7a2e78099a08c the abort lock is held at the time of __clone, which precludes the child inheriting a kernel-level signal disposition inconsistent with the disposition on the abstract machine. this means it's fine to inspect and modify the disposition in the child without a lock.
2020-10-18update crypt_blowfish to support $2b$ prefixJulien Ramseier-15/+23
Merge changes from Solar Designer's crypt_blowfish v1.3. This makes crypt_blowfish fully compatible with OpenBSD's bcrypt by adding support for the $2b$ prefix (which behaves the same as crypt_blowfish's $2y$).
2020-10-14remove unused weak definition of __tl_sync in membarrier.cRich Felker-5/+0
2020-10-14move aio implementation details to a proper internal headerRich Felker-4/+14
also fix the lack of declaration (and thus hidden visibility) in __stdio_close's use of __aio_close.
2020-10-14remove long-unused struct __timer from pthread_impl.hRich Felker-5/+0
commit 3990c5c6a40440cdb14746ac080d0ecf8d5d6733 removed the last reference.
2020-10-14drop use of pthread_once in timer_createRich Felker-10/+7
this makes the code slightly smaller and eliminates timer_create from relevance to possible future changes to multithreaded fork. the barrier of a_store isn't technically needed here, but a_store is used anyway for internal consistency of the memory model.
2020-10-14remove unused SIGTIMER handler in timer_createRich Felker-6/+1
this was leftover from when the actual SIGEV_THREAD timer logic was in the signal handler. commit 5b74eed3b301e2227385f3bf26d3bb7c2d822cf8 replaced that with use of sigwaitinfo, with the actual signal left blocked, so the no-op signal handler was no longer serving any purpose. the signal disposition reset to SIG_DFL is still needed, however, in case we inherited SIG_IGN from a foreign-libc process.
2020-10-14remove incorrect fflush from assert failure handlerRich Felker-1/+0
assert is not specified to flush open stdio streams, and doing so can block indefinitely waiting for a lock already held or an output operation to a file that can't accept more output until an unsatisfiable condition is met.
2020-10-14fix getgrouplist when nscd reports an empty listRich Felker-1/+2
commit 500c6886c654fd45e4926990fee2c61d816be197 broke this by fixing the behavior of fread to conform to the C standard; getgroupslist was assuming the old behavior, that a request to read 1 member of length 0 would return 1, not 0.
2020-10-14fix posix_spawn interaction with fork and abort by taking lockRich Felker-3/+13
this change prevents the child created concurrently with abort from seeing the SIGABRT disposition change from SIG_IGN to SIG_DFL (other changes are not visible anyway) and prevents leaking the write end of the child pipe to children created by fork in another thread, which may block return of posix_spawn indefinitely if the forked child does not exit or exec. along with other changes, this suggests that __abort_lock should perhaps eventually be renamed to reflect that it's becoming a broader lock on related "process lifetime" state.
2020-10-14fix unintended observability of SIGABRT disposition reset via sigactionRich Felker-9/+8
the existing abort locking logic in sigaction only accounted for attempts to change the disposition, not attempts to observe the change made by abort. unfortunately the change is still observable in at least one other place: inheritance of signal dispositions across exec and posix_spawn. fixing these is a separate task and it's not even clear whether a complete fix is possible.
2020-10-14implement _Fork and refactor fork using itRich Felker-9/+16
the _Fork interface is defined for future issue of POSIX as the outcome of Austin Group issue 62, which drops the AS-safety requirement for fork, and provides an AS-safe replacement that does not run the registered atfork handlers.
2020-10-14rename fork source fileRich Felker-0/+0
this is in preparation for implementing _Fork from POSIX-future, factored as a separate commit to improve readability of history.
2020-10-14ldso: use pthread_t rather than kernel tid to track ctor visitorRich Felker-3/+3
commit 188759bbee057aa94db2bbb7cf7f5855f3b9ab53 documented the intent to allow recursive dlopen based on tracking ctor_visitor, but used a kernel tid rather than the pthread_t to identify the caller. as a result, it would not behave as intended under fork by a ctor, where the child tid would not match.
2020-10-14fix stale lock when allocation of ctor queue fails during dlopenRich Felker-1/+2
queue_ctors should not be called with the init_fini_lock held, since it may longjmp out on allocation failure. this introduces a minor TOCTOU race with p->constructed, but one already exists further down anyway, and by design it's okay to run through the queue more than once anyway. the only reason we bother to check p->constructed at all is to avoid spurious failure of dlopen when the library is already fully loaded and constructed.
2020-10-14drop use of pthread_once in mutexattr kernel support testsRich Felker-21/+18
this makes the code slightly smaller and eliminates these functions from relevance to possible future changes to multithreaded fork. the barrier of a_store isn't technically needed here, but a_store is used anyway for internal consistency of the memory model.
2020-10-14fix missing synchronization of fork with abortRich Felker-0/+3
if the multithreaded parent forked while another thread was calling sigaction for SIGABRT or calling abort, the child could inherit a lock state in which future calls to abort will deadlock, or in which the disposition for SIGABRT has already been reset to SIG_DFL. this is nonconforming since abort is AS-safe and permitted to be called concurrently with fork or in the MT-forked child.
2020-10-14move __abort_lock to its own file and drop pointless weak_alias trickRich Felker-8/+5
the dummy definition of __abort_lock in sigaction.c was performing exactly the same role that putting the lock in its own source file could and should have been used to achieve. while we're moving it, give it a proper declaration.
2020-09-28fix fork of processes with active async io contextsRich Felker-0/+19
previously, if a file descriptor had aio operations pending in the parent before fork, attempting to close it in the child would attempt to cancel a thread belonging to the parent. this could deadlock, fail, or crash the whole process of the cancellation signal handler was not yet installed in the parent. in addition, further use of aio from the child could malfunction or deadlock. POSIX specifies that async io operations are not inherited by the child on fork, so clear the entire aio fd map in the child, and take the aio map lock (with signals blocked) across the fork so that the lock is kept in a consistent state.
2020-09-17avoid set*id/setrlimit misbehavior and hang in vforked/cloned childRich Felker-1/+2
taking the deprecated/dropped vfork spec strictly, doing pretty much anything but execve in the child is wrong and undefined. however, these are commonly needed operations to setup the child state before exec, and historical implementations tolerated them. for single-threaded parents, these operations already worked as expected in the vforked child. however, due to the need for __synccall to synchronize id/resource limit changes among all threads, calling these functions in the vforked child of a multithreaded parent caused a misdirected broadcast signaling of all threads in the parent. these signals could kill the parent entirely if the synccall signal handler had never been installed in the parent, or could be ignored if it had, or could signal/kill one or more utterly wrong processes if the parent already terminated (due to vfork semantics, only possible via fatal signal) and the parent tids were recycled. in any case, the expected number of semaphore posts would never happen, so the child would permanently hang (with all signals blocked) waiting for them. to mitigate this, and also make the normal usage case work as intended, treat the condition where the caller's actual tid does not match the tid in its thread structure as single-threaded, and bypass the entire synccall broadcast operation.
2020-09-09use new SYS_faccessat2 syscall to implement faccessat with flagsRich Felker-3/+8
commit 0a05eace163cee9b08571d2ff9d90f5e82d9c228 implemented AT_EACCESS for faccessat with a horrible hack, creating a child process to change switch uid/gid and perform the access probe without making potentially irreversible changes to the caller's credentials. this was due to the syscall lacking a flags argument. linux 5.8 introduced a new syscall, SYS_faccessat2, fixing this deficiency. use it if any flags are passed, and fallback to the old strategy on ENOSYS. continue using the old syscall when there are no flags.
2020-09-09netinet/if_ether.h: add ETH_P_MRP from linux v5.8Szabolcs Nagy-0/+1
Ethernet protocol number for media redundancy protocol, see linux commit 4714d13791f831d253852c8b5d657270becb8b2a bridge: uapi: mrp: Add mrp attributes.
2020-09-09elf.h: add .note.gnu.property related definitionsSzabolcs Nagy-0/+2
On x86 and aarch64 GNU properties may be used to mark ELF objects.
2020-09-09bits/syscall.h: add __NR_faccessat2 from linux v5.8Szabolcs Nagy-0/+16
the linux faccessat syscall lacks a flag argument that is necessary to implement the posix api, see linux commit c8ffd8bcdd28296a198f237cc595148a8d4adfbe vfs: add faccessat2 syscall
2020-09-09netinet/tcp.h: update to linux v5.7Szabolcs Nagy-0/+3
add TCP_NLA_BYTES_NOTSENT and new tcp_zerocopy_receive fields, see linux commit c8856c051454909e5059df4e81c77b9c366c5515 tcp-zerocopy: Return inq along with tcp receive zerocopy. linux commit 33946518d493cdf10aedb4a483f1aa41948a3dab tcp-zerocopy: Return sk_err (if set) along with tcp receive zerocopy. linux commit e08ab0b377a1489760533424437c5f4be7f484a4 tcp: add bytes not sent to SCM_TIMESTAMPING_OPT_STATS
2020-09-09sys/mman.h: add MREMAP_DONTUNMAP from linux v5.7Szabolcs Nagy-0/+1
it remaps anon mappings without unmapping the original. chromeos plans to use it with userfaultfd, see: linux commit e346b3813067d4b17383f975f197a9aa28a3b077 mm/mremap: add MREMAP_DONTUNMAP to mremap()
2020-09-09sys/fanotify.h: update to linux v5.7Szabolcs Nagy-1/+3
see linux commit 9e2ba2c34f1922ca1e0c7d31b30ace5842c2e7d1 fanotify: send FAN_DIR_MODIFY event flavor with dir inode and name linux commit 44d705b0370b1d581f46ff23e5d33e8b5ff8ec58 fanotify: report name info for FAN_DIR_MODIFY event
2020-09-09aarch64: add new HWCAP2_ macros from linux v5.6Szabolcs Nagy-0/+8
added in linux commit 1a50ec0b3b2e9a83f1b1245ea37a853aac2f741c arm64: Implement archrandom.h for ARMv8.5-RNG linux commit d4209d8b717311d114b5d47ba7f8249fd44e97c2 arm64: cpufeature: Export matrix and other features to userspace
2020-09-09aarch64: add HWCAP2_ macros from linux v5.3Szabolcs Nagy-0/+2
these were missed before, added in linux commit 1201937491822b61641c1878ebcd16a93aed4540 arm64: Expose ARMv8.5 CondM capability to userspace linux commit ca9503fc9e9812aa6258e55d44edb03eb30fc46f arm64: Expose FRINT capabilities to userspace
2020-09-09sched.h: add CLONE_NEWTIME from linux v5.6Szabolcs Nagy-0/+1
reuses a bit from CSIGNAL so it can only be used with unshare and clone3, added in linux commit 769071ac9f20b6a447410c7eaa55d1a5233ef40c ns: Introduce Time Namespace
2020-09-09sys/random.h: add GRND_INSECURE from linux v5.6Szabolcs Nagy-0/+1
added in linux commit 75551dbf112c992bc6c99a972990b3f272247e23 random: add GRND_INSECURE to return best-effort non-cryptographic bytes
2020-09-09sys/prctl.h: add PR_{SET,GET}_IO_FLUSHER from linux v5.6Szabolcs Nagy-0/+3
needed for storage drivers with userspace component that may run in the IO path, see linux commit 8d19f1c8e1937baf74e1962aae9f90fa3aeab463 prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim
2020-09-09netinet/udp.h: add TCP_ENCAP_ESPINTCP from linux v5.6Szabolcs Nagy-0/+1
The use of TCP_ in udp.h is not known, fortunately udp.h is not specified by posix so there are no strict namespace rules, added in linux commit e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 xfrm: add espintcp (RFC 8229)
2020-09-09netinet/tcp.h: update for linux v5.6Szabolcs Nagy-2/+4
TCP_NLA_TIMEOUT_REHASH queries timeout-triggered rehash attempts, tcpm_ifindex limits the scope of TCP_MD5SIG* sockopt to a device. see linux commit 32efcc06d2a15fa87585614d12d6c2308cc2d3f3 tcp: export count for rehash attempts linux commit 6b102db50cdde3ba2f78631ed21222edf3a5fb51 net: Add device index to tcp_md5sig
2020-09-09netinet/in.h: add IPPROTO_ macros from linux v5.6Szabolcs Nagy-1/+3
add IPPROTO_ETHERNET and IPPROTO_MPTCP, see linux commit 2677625387056136e256c743e3285b4fe3da87bb seg6: fix SRv6 L2 tunnels to use IANA-assigned protocol number linux commit faf391c3826cd29feae02078ca2022d2f912f7cc tcp: Define IPPROTO_MPTCP
2020-09-09add pidfd_getfd and openat2 syscall numbers from linux v5.6Szabolcs Nagy-0/+34
also added clone3 on sh and m68k, on sh it's still missing (not yet wired up), but reserved so safe to add. see linux commit fddb5d430ad9fa91b49b1d34d0202ffe2fa0e179 open: introduce openat2(2) syscall linux commit 9a2cef09c801de54feecd912303ace5c27237f12 arch: wire up pidfd_getfd syscall linux commit 8649c322f75c96e7ced2fec201e123b2b073bf09 pid: Implement pidfd_getfd syscall linux commit e8bb2a2a1d51511e6b3f7e08125d52ec73c11139 m68k: Wire up clone3() syscall
2020-09-09netinet/tcp.h: update tcp_info for linux v5.5Szabolcs Nagy-1/+8
see linux commit 480274787d7e3458bc5a7cfbbbe07033984ad711 tcp: add TCP_INFO status for failed client TFO
2020-09-03use generic bits/fcntl.h for x86_64 and riscv64Rich Felker-78/+0
these were only using a custom version because they needed the "non-64" variants of the file locking command macros.
2020-09-03make generic bits/fcntl.h shareable with 64-bit archsRich Felker-0/+6
the fcntl file locking command macro values in the existing generic bits/fcntl.h were the "64" variants, requiring 64-bit archs that use the "plain" variants to have their own bits/fcntl.h, even if they otherwise use the common definitions for everything. since commit 7cc79d10afd43811a486fd5e9fcdf8e45ac599e0 exposed __LONG_MAX to all bits headers, we can now make the generic one common between 32- and 64-bit archs.
2020-09-03fix missing O_LARGEFILE values on x86_64, x32, and mips64Rich Felker-3/+3
prior to commit 685e40bb09f5f24a2af54ea09c97328808f76990, x86_64 was correctly passing O_LARGEFILE to SYS_open; it was removed (defined to 0 in the public header, and changed to use the public definition) as part of that change, probably out of a mistaken belief that it's not needed. however, on a mixed system with 32-bit and 64-bit binaries, it's important that all files be opened with O_LARGEFILE, even if the opening process is 64-bit, in case a descriptor is passed to a 32-bit process. otherwise, attempts to access past 2GB in the 32-bit process could produce EOVERFLOW. most 64-bit archs added later got this right alread, except for mips64. x32 was also affected. there are now fixed.
2020-09-03fix missing newline in herror outputRich Felker-1/+1
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