mirror of
https://github.com/jart/cosmopolitan.git
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120 lines
4.5 KiB
C
120 lines
4.5 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/fmt/itoa.h"
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#include "libc/intrin/cmpxchg.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/intrin/lockcmpxchg.h"
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#include "libc/intrin/nopl.h"
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#include "libc/intrin/pthread.h"
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#include "libc/macros.internal.h"
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#include "libc/nexgen32e/stackframe.h"
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#include "libc/nexgen32e/threaded.h"
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#include "libc/runtime/stack.h"
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#include "libc/runtime/symbols.internal.h"
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#define MAX_NESTING 512
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/**
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* @fileoverview Plain-text function call logging.
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*
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* Able to log ~2 million function calls per second, which is mostly
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* bottlenecked by system call overhead. Log size is reasonable if piped
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* into gzip.
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*/
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void ftrace_hook(void);
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static struct Ftrace {
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int skew;
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int stackdigs;
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int64_t lastaddr;
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pthread_mutex_t lock;
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volatile bool noreentry;
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} g_ftrace;
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static void __ftrace_lock(void) {
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if (__threaded) {
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pthread_mutex_lock(&g_ftrace.lock);
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}
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}
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static void __ftrace_unlock(void) {
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if (__threaded) {
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pthread_mutex_unlock(&g_ftrace.lock);
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}
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}
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static privileged inline int GetNestingLevelImpl(struct StackFrame *frame) {
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int nesting = -2;
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while (frame) {
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++nesting;
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frame = frame->next;
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}
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return MAX(0, nesting);
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}
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static privileged inline int GetNestingLevel(struct StackFrame *frame) {
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int nesting;
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nesting = GetNestingLevelImpl(frame);
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if (nesting < g_ftrace.skew) g_ftrace.skew = nesting;
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nesting -= g_ftrace.skew;
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return MIN(MAX_NESTING, nesting);
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}
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/**
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* Prints name of function being called.
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*
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* We insert CALL instructions that point to this function, in the
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* prologues of other functions. We assume those functions behave
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* according to the System Five NexGen32e ABI.
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*/
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privileged void ftracer(void) {
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long stackuse;
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struct StackFrame *frame;
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__ftrace_lock();
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if (_cmpxchg(&g_ftrace.noreentry, false, true)) {
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frame = __builtin_frame_address(0);
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frame = frame->next;
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if (frame->addr != g_ftrace.lastaddr) {
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stackuse = GetStackAddr() + GetStackSize() - (intptr_t)frame;
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kprintf("%rFUN %6P %'13T %'*ld %*s%t\n", g_ftrace.stackdigs, stackuse,
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GetNestingLevel(frame) * 2, "", frame->addr);
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g_ftrace.lastaddr = frame->addr;
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}
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g_ftrace.noreentry = false;
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}
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__ftrace_unlock();
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}
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textstartup int ftrace_install(void) {
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pthread_mutexattr_t attr;
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pthread_mutexattr_init(&attr);
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pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
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pthread_mutex_init(&g_ftrace.lock, &attr);
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if (GetSymbolTable()) {
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g_ftrace.lastaddr = -1;
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g_ftrace.stackdigs = LengthInt64Thousands(GetStackSize());
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g_ftrace.skew = GetNestingLevelImpl(__builtin_frame_address(0));
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return __hook(ftrace_hook, GetSymbolTable());
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} else {
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kprintf("error: --ftrace failed to open symbol table\n");
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return -1;
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}
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}
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