mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
8cdec62f5b
- Finish cleaning up the stdio unlocked APIs - Make __cxa_finalize() properly thread safe - Don't log locks if threads aren't being used - Add some more mutex guards to places using _mmi - Specific lock names now appear in the --ftrace logs - Fix mkdeps.com generating invalid Makefiles sometimes - Simplify and fix bugs in the test runner infrastructure - Fix issue where sometimes some functions wouldn't be logged
113 lines
4.3 KiB
C
113 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/dce.h"
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#include "libc/nexgen32e/gettls.h"
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#include "libc/nexgen32e/threaded.h"
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#include "libc/nt/thread.h"
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#include "libc/nt/thunk/msabi.h"
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#include "libc/runtime/internal.h"
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__msabi extern typeof(GetCurrentThreadId) *const __imp_GetCurrentThreadId;
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/**
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* Returns current thread id.
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*
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* On Linux, and Linux only, this is guaranteed to be equal to getpid()
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* if this is the main thread. On NetBSD, gettid() for the main thread
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* is always 1.
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*
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* This function issues a system call. That stops being the case as soon
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* as __install_tls() is called. That'll happen automatically, when you
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* call clone() and provide the TLS parameter. We assume that when a TLS
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* block exists, then
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*
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* *(int *)(__get_tls() + 0x38)
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*
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* will contain the thread id. Therefore when issuing clone() calls, the
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* `CLONE_CHILD_SETTID` and `CLONE_CHILD_CLEARTID` flags should use that
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* index as its `ctid` memory.
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*
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* gettid (single threaded) l: 126𝑐 41𝑛𝑠
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* gettid (tls enabled) l: 2𝑐 1𝑛𝑠
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*
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* The TLS convention is important for reentrant lock performance.
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*
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* @return thread id greater than zero or -1 w/ errno
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* @asyncsignalsafe
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* @threadsafe
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*/
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privileged int gettid(void) {
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int rc;
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int64_t wut;
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struct WinThread *wt;
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if (__tls_enabled) {
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rc = *(int *)(__get_tls_inline() + 0x38);
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return rc;
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}
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if (IsWindows()) {
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return __imp_GetCurrentThreadId();
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}
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if (IsLinux()) {
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asm("syscall"
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: "=a"(rc) // man says always succeeds
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: "0"(186) // __NR_gettid
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: "rcx", "r11", "memory");
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return rc;
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}
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if (IsXnu()) {
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asm("syscall" // xnu/osfmk/kern/ipc_tt.c
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: "=a"(rc) // assume success
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: "0"(0x1000000 | 27) // Mach thread_self_trap()
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: "rcx", "r11", "memory", "cc");
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return rc;
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}
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if (IsOpenbsd()) {
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asm("syscall"
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: "=a"(rc) // man says always succeeds
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: "0"(299) // getthrid()
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: "rcx", "r11", "memory", "cc");
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return rc;
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}
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if (IsNetbsd()) {
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asm("syscall"
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: "=a"(rc) // man says always succeeds
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: "0"(311) // _lwp_self()
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: "rcx", "rdx", "r11", "memory", "cc");
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return rc;
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}
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if (IsFreebsd()) {
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asm("syscall"
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: "=a"(rc), // only fails w/ EFAULT, which isn't possible
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"=m"(wut) // must be 64-bit
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: "0"(432), // thr_self()
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"D"(&wut) // but not actually 64-bit
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: "rcx", "r11", "memory", "cc");
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return wut; // narrowing intentional
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}
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return __pid;
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}
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