mirror of
https://github.com/jart/cosmopolitan.git
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Make improvements
- Every unit test now passes on Apple Silicon. The final piece of this puzzle was porting our POSIX threads cancelation support, since that works differently on ARM64 XNU vs. AMD64. Our semaphore support on Apple Silicon is also superior now compared to AMD64, thanks to the grand central dispatch library which lets *NSYNC locks go faster. - The Cosmopolitan runtime is now more stable, particularly on Windows. To do this, thread local storage is mandatory at all runtime levels, and the innermost packages of the C library is no longer being built using ASAN. TLS is being bootstrapped with a 128-byte TIB during the process startup phase, and then later on the runtime re-allocates it either statically or dynamically to support code using _Thread_local. fork() and execve() now do a better job cooperating with threads. We can now check how much stack memory is left in the process or thread when functions like kprintf() / execve() etc. call alloca(), so that ENOMEM can be raised, reduce a buffer size, or just print a warning. - POSIX signal emulation is now implemented the same way kernels do it with pthread_kill() and raise(). Any thread can interrupt any other thread, regardless of what it's doing. If it's blocked on read/write then the killer thread will cancel its i/o operation so that EINTR can be returned in the mark thread immediately. If it's doing a tight CPU bound operation, then that's also interrupted by the signal delivery. Signal delivery works now by suspending a thread and pushing context data structures onto its stack, and redirecting its execution to a trampoline function, which calls SetThreadContext(GetCurrentThread()) when it's done. - We're now doing a better job managing locks and handles. On NetBSD we now close semaphore file descriptors in forked children. Semaphores on Windows can now be canceled immediately, which means mutexes/condition variables will now go faster. Apple Silicon semaphores can be canceled too. We're now using Apple's pthread_yield() funciton. Apple _nocancel syscalls are now used on XNU when appropriate to ensure pthread_cancel requests aren't lost. The MbedTLS library has been updated to support POSIX thread cancelations. See tool/build/runitd.c for an example of how it can be used for production multi-threaded tls servers. Handles on Windows now leak less often across processes. All i/o operations on Windows are now overlapped, which means file pointers can no longer be inherited across dup() and fork() for the time being. - We now spawn a thread on Windows to deliver SIGCHLD and wakeup wait4() which means, for example, that posix_spawn() now goes 3x faster. POSIX spawn is also now more correct. Like Musl, it's now able to report the failure code of execve() via a pipe although our approach favors using shared memory to do that on systems that have a true vfork() function. - We now spawn a thread to deliver SIGALRM to threads when setitimer() is used. This enables the most precise wakeups the OS makes possible. - The Cosmopolitan runtime now uses less memory. On NetBSD for example, it turned out the kernel would actually commit the PT_GNU_STACK size which caused RSS to be 6mb for every process. Now it's down to ~4kb. On Apple Silicon, we reduce the mandatory upstream thread size to the smallest possible size to reduce the memory overhead of Cosmo threads. The examples directory has a program called greenbean which can spawn a web server on Linux with 10,000 worker threads and have the memory usage of the process be ~77mb. The 1024 byte overhead of POSIX-style thread-local storage is now optional; it won't be allocated until the pthread_setspecific/getspecific functions are called. On Windows, the threads that get spawned which are internal to the libc implementation use reserve rather than commit memory, which shaves a few hundred kb. - sigaltstack() is now supported on Windows, however it's currently not able to be used to handle stack overflows, since crash signals are still generated by WIN32. However the crash handler will still switch to the alt stack, which is helpful in environments with tiny threads. - Test binaries are now smaller. Many of the mandatory dependencies of the test runner have been removed. This ensures many programs can do a better job only linking the the thing they're testing. This caused the test binaries for LIBC_FMT for example, to decrease from 200kb to 50kb - long double is no longer used in the implementation details of libc, except in the APIs that define it. The old code that used long double for time (instead of struct timespec) has now been thoroughly removed. - ShowCrashReports() is now much tinier in MODE=tiny. Instead of doing backtraces itself, it'll just print a command you can run on the shell using our new `cosmoaddr2line` program to view the backtrace. - Crash report signal handling now works in a much better way. Instead of terminating the process, it now relies on SA_RESETHAND so that the default SIG_IGN behavior can terminate the process if necessary. - Our pledge() functionality has now been fully ported to AARCH64 Linux.
This commit is contained in:
Justine Tunney
parent
c4eb838516
commit
ec480f5aa0
638 changed files with 7925 additions and 8282 deletions
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@ -18,19 +18,29 @@
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/sig.internal.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/struct/siginfo.h"
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#include "libc/calls/struct/sigset.h"
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#include "libc/calls/struct/ucontext.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/calls/syscall_support-sysv.internal.h"
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#include "libc/calls/ucontext.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/nt/enum/context.h"
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#include "libc/nt/enum/threadaccess.h"
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#include "libc/nt/runtime.h"
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#include "libc/nt/struct/context.h"
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#include "libc/nt/thread.h"
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#include "libc/runtime/runtime.h"
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#include "libc/runtime/syslib.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/sa.h"
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#include "libc/sysv/consts/sicode.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/posixthread.internal.h"
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@ -42,42 +52,135 @@ int systemfive_cancel(void);
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extern const char systemfive_cancellable[];
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extern const char systemfive_cancellable_end[];
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long _pthread_cancel_sys(void) {
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struct PosixThread *pt;
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pt = (struct PosixThread *)__get_tls()->tib_pthread;
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if (!(pt->flags & (PT_NOCANCEL | PT_MASKED)) || (pt->flags & PT_ASYNC)) {
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long _pthread_cancel_ack(void) {
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struct PosixThread *pt = _pthread_self();
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if (!(pt->pt_flags & (PT_NOCANCEL | PT_MASKED)) ||
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(pt->pt_flags & PT_ASYNC)) {
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pthread_exit(PTHREAD_CANCELED);
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}
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pt->flags |= PT_NOCANCEL | PT_OPENBSD_KLUDGE;
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pt->pt_flags |= PT_NOCANCEL | PT_OPENBSD_KLUDGE;
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return ecanceled();
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}
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static void OnSigThr(int sig, siginfo_t *si, void *ctx) {
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ucontext_t *uc = ctx;
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struct CosmoTib *t;
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static void _pthread_cancel_sig(int sig, siginfo_t *si, void *arg) {
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ucontext_t *ctx = arg;
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// check thread runtime state is initialized and cancelled
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struct PosixThread *pt;
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if ((t = __get_tls()) && // TODO: why can it be null on freebsd?
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(pt = (struct PosixThread *)t->tib_pthread) &&
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!(pt->flags & PT_NOCANCEL) &&
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atomic_load_explicit(&pt->cancelled, memory_order_acquire)) {
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sigaddset(&uc->uc_sigmask, sig);
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if (systemfive_cancellable <= (char *)uc->uc_mcontext.PC &&
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(char *)uc->uc_mcontext.PC < systemfive_cancellable_end) {
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uc->uc_mcontext.PC = (intptr_t)systemfive_cancel;
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} else if (pt->flags & PT_ASYNC) {
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pthread_exit(PTHREAD_CANCELED);
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} else {
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__tkill(atomic_load_explicit(&t->tib_tid, memory_order_relaxed), sig, t);
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if (!__tls_enabled) return;
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if (!(pt = _pthread_self())) return;
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if (pt->pt_flags & PT_NOCANCEL) return;
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if (!atomic_load_explicit(&pt->cancelled, memory_order_acquire)) return;
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// in asynchronous mode we'll just the exit asynchronously
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if (pt->pt_flags & PT_ASYNC) {
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sigaddset(&ctx->uc_sigmask, SIGTHR);
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pthread_sigmask(SIG_SETMASK, &ctx->uc_sigmask, 0);
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pthread_exit(PTHREAD_CANCELED);
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}
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// prevent this handler from being called again by thread
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sigaddset(&ctx->uc_sigmask, SIGTHR);
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// check for race condition between pre-check and syscall
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// rewrite the thread's execution state to acknowledge it
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if (systemfive_cancellable <= (char *)ctx->uc_mcontext.PC &&
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(char *)ctx->uc_mcontext.PC < systemfive_cancellable_end) {
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ctx->uc_mcontext.PC = (intptr_t)systemfive_cancel;
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return;
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}
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// punts cancellation to start of next cancellation point
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// we ensure sigthr is a pending signal in case unblocked
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if (IsXnuSilicon()) {
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__syslib->__pthread_kill(_pthread_syshand(pt), sig);
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} else {
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sys_tkill(_pthread_tid(pt), sig, __get_tls());
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}
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}
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static void _pthread_cancel_listen(void) {
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struct sigaction sa;
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if (!IsWindows()) {
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sa.sa_sigaction = _pthread_cancel_sig;
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sa.sa_flags = SA_SIGINFO | SA_RESTART;
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memset(&sa.sa_mask, -1, sizeof(sa.sa_mask));
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npassert(!sigaction(SIGTHR, &sa, 0));
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}
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}
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static void pthread_cancel_nt(struct PosixThread *pt, intptr_t hThread) {
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uint32_t old_suspend_count;
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if ((pt->pt_flags & PT_ASYNC) && !(pt->pt_flags & PT_NOCANCEL)) {
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if ((old_suspend_count = SuspendThread(hThread)) != -1u) {
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if (!old_suspend_count) {
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struct NtContext cpu;
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cpu.ContextFlags = kNtContextControl | kNtContextInteger;
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if (GetThreadContext(hThread, &cpu)) {
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pt->pt_flags |= PT_NOCANCEL;
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cpu.Rip = (uintptr_t)pthread_exit;
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cpu.Rdi = (uintptr_t)PTHREAD_CANCELED;
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cpu.Rsp &= -16;
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*(uintptr_t *)(cpu.Rsp -= sizeof(uintptr_t)) = cpu.Rip;
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unassert(SetThreadContext(hThread, &cpu));
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__sig_cancel(pt, 0);
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}
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}
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ResumeThread(hThread);
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}
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}
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}
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static void ListenForSigThr(void) {
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struct sigaction sa;
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sa.sa_sigaction = OnSigThr;
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sa.sa_flags = SA_SIGINFO | SA_RESTART | SA_ONSTACK;
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memset(&sa.sa_mask, -1, sizeof(sa.sa_mask));
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npassert(!sigaction(SIGTHR, &sa, 0));
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static errno_t _pthread_cancel_impl(struct PosixThread *pt) {
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// install our special signal handler
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static bool once;
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if (!once) {
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_pthread_cancel_listen();
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once = true;
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}
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// check if thread is already dead
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switch (atomic_load_explicit(&pt->status, memory_order_acquire)) {
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case kPosixThreadZombie:
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case kPosixThreadTerminated:
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return ESRCH;
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default:
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break;
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}
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// flip the bit indicating that this thread is cancelled
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atomic_store_explicit(&pt->cancelled, 1, memory_order_release);
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// does this thread want to cancel itself?
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if (pt == _pthread_self()) {
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unassert(!(pt->pt_flags & PT_NOCANCEL));
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if (!(pt->pt_flags & (PT_NOCANCEL | PT_MASKED)) &&
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(pt->pt_flags & PT_ASYNC)) {
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pthread_exit(PTHREAD_CANCELED);
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}
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return 0;
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}
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errno_t err;
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if (IsWindows()) {
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pthread_cancel_nt(pt, _pthread_syshand(pt));
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err = 0;
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} else if (IsXnuSilicon()) {
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err = __syslib->__pthread_kill(_pthread_syshand(pt), SIGTHR);
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} else {
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int e = errno;
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if (!sys_tkill(_pthread_tid(pt), SIGTHR, pt->tib)) {
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err = 0;
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} else {
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err = errno;
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errno = e;
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}
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}
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if (err == ESRCH) {
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err = 0; // we already reported this
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}
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return err;
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}
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/**
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@ -153,6 +256,7 @@ static void ListenForSigThr(void) {
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* - `nsync_cv_wait_with_deadline`
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* - `nsync_cv_wait`
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* - `opendir`
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* - `openatemp`, 'mkstemp', etc.
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* - `pclose`
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* - `popen`
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* - `fwrite`, `printf`, `fprintf`, `putc`, etc.
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@ -174,7 +278,7 @@ static void ListenForSigThr(void) {
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* - `INFOF()`, `WARNF()`, etc.
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* - `getentropy`
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* - `gmtime_r`
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* - `kprintf`
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* - `kprintf` (by virtue of asm(syscall) and write_nocancel() on xnu)
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* - `localtime_r`
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* - `nsync_mu_lock`
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* - `nsync_mu_unlock`
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@ -185,6 +289,7 @@ static void ListenForSigThr(void) {
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* - `pthread_setname_np`
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* - `sem_open`
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* - `system`
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* - `openatemp`, 'mkstemp', etc.
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* - `timespec_sleep`
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* - `touch`
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*
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*
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* Isn't safe to use in masked mode. That's because if a cancellation
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* occurs during the write() operation then cancellations are blocked
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* while running read(). Masked mode doesn't have second chances. You
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* while running read(). MASKED MODE DOESN'T HAVE SECOND CHANCES. You
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* must rigorously check the results of each cancellation point call.
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*
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* Unit tests should be able to safely ignore the return value, or at
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* the very least be programmed to consider ESRCH a successful status
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*
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* @param thread may be 0 to cancel all threads except self
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* @return 0 on success, or errno on error
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* @raise ESRCH if system thread wasn't alive or we lost a race
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*/
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errno_t pthread_cancel(pthread_t thread) {
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int e, rc, tid;
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static bool once;
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struct PosixThread *pt;
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__require_tls();
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if (!once) {
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ListenForSigThr();
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once = true;
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}
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pt = (struct PosixThread *)thread;
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switch (atomic_load_explicit(&pt->status, memory_order_acquire)) {
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case kPosixThreadZombie:
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case kPosixThreadTerminated:
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return ESRCH;
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default:
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break;
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}
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atomic_store_explicit(&pt->cancelled, 1, memory_order_release);
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if (thread == __get_tls()->tib_pthread) {
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if (!(pt->flags & (PT_NOCANCEL | PT_MASKED)) && (pt->flags & PT_ASYNC)) {
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pthread_exit(PTHREAD_CANCELED);
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}
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return 0;
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}
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if (!(rc = pthread_getunique_np(thread, &tid))) {
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if (!IsWindows()) {
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e = errno;
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if (!__tkill(tid, SIGTHR, pt->tib)) {
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rc = 0;
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} else {
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rc = errno;
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errno = e;
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errno_t err;
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struct Dll *e;
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struct PosixThread *arg, *other;
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if ((arg = (struct PosixThread *)thread)) {
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err = _pthread_cancel_impl(arg);
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} else {
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err = ESRCH;
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pthread_spin_lock(&_pthread_lock);
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for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
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other = POSIXTHREAD_CONTAINER(e);
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if (other != _pthread_self() &&
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atomic_load_explicit(&other->status, memory_order_acquire) <
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kPosixThreadTerminated) {
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_pthread_cancel_impl(other);
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err = 0;
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}
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} else {
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rc = 0;
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}
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pthread_spin_unlock(&_pthread_lock);
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}
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return rc;
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STRACE("pthread_cancel(%d) → %s", _pthread_tid(arg), DescribeErrno(err));
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return err;
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}
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/**
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@ -317,9 +407,9 @@ errno_t pthread_cancel(pthread_t thread) {
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void pthread_testcancel(void) {
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struct PosixThread *pt;
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if (!__tls_enabled) return;
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if (!(pt = (struct PosixThread *)__get_tls()->tib_pthread)) return;
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if (pt->flags & PT_NOCANCEL) return;
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if ((!(pt->flags & PT_MASKED) || (pt->flags & PT_ASYNC)) &&
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if (!(pt = _pthread_self())) return;
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if (pt->pt_flags & PT_NOCANCEL) return;
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if ((!(pt->pt_flags & PT_MASKED) || (pt->pt_flags & PT_ASYNC)) &&
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atomic_load_explicit(&pt->cancelled, memory_order_acquire)) {
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pthread_exit(PTHREAD_CANCELED);
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}
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@ -344,13 +434,13 @@ void pthread_testcancel(void) {
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errno_t pthread_testcancel_np(void) {
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struct PosixThread *pt;
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if (!__tls_enabled) return 0;
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if (!(pt = (struct PosixThread *)__get_tls()->tib_pthread)) return 0;
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if (pt->flags & PT_NOCANCEL) return 0;
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if (!(pt = _pthread_self())) return 0;
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if (pt->pt_flags & PT_NOCANCEL) return 0;
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if (!atomic_load_explicit(&pt->cancelled, memory_order_acquire)) return 0;
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if (!(pt->flags & PT_MASKED) || (pt->flags & PT_ASYNC)) {
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if (!(pt->pt_flags & PT_MASKED) || (pt->pt_flags & PT_ASYNC)) {
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pthread_exit(PTHREAD_CANCELED);
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} else {
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pt->flags |= PT_NOCANCEL;
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pt->pt_flags |= PT_NOCANCEL;
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return ECANCELED;
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}
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}
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