mirror of
https://github.com/jart/cosmopolitan.git
synced 2024-05-12 16:42:41 +00:00
a4b455185b
Renaming gc() to _gc() was a mistake since the better thing to do is put it behind the _COSMO_SOURCE macro. We need this change because I haven't wanted to use my amazing garbage collector ever since we renamed it. You now need to define _COSMO_SOURCE yourself when using amalgamation header and cosmocc users need to pass the -mcosmo flag to get the gc() function Some other issues relating to cancelation have been fixed along the way. We're also now putting cosmocc in a folder named `.cosmocc` so it can be more safely excluded by grep --exclude-dir=.cosmocc --exclude-dir=o etc.
112 lines
4.4 KiB
C
112 lines
4.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 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/struct/rlimit.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/struct/sigaltstack.h"
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#include "libc/calls/struct/siginfo.h"
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#include "libc/dce.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/limits.h"
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#include "libc/mem/gc.h"
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#include "libc/mem/mem.h"
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#include "libc/runtime/runtime.h"
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#include "libc/runtime/sysconf.h"
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#include "libc/stdio/sysparam.h"
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#include "libc/sysv/consts/rlimit.h"
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#include "libc/sysv/consts/sa.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/sysv/consts/ss.h"
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#include "libc/testlib/testlib.h"
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#include "libc/thread/thread.h"
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/**
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* stack overflow recovery technique #1
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* overflow the gigantic main process stack
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* simple but it can upset kernels / libraries
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*/
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jmp_buf recover;
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volatile bool smashed_stack;
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void CrashHandler(int sig, siginfo_t *si, void *ctx) {
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struct sigaltstack ss;
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ASSERT_SYS(0, 0, sigaltstack(0, &ss));
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ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
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kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
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smashed_stack = true;
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ASSERT_TRUE(__is_stack_overflow(si, ctx));
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longjmp(recover, 123);
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}
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void SetUp(void) {
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// tune down the main process's stack size to a reasonable amount
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// some operating systems, e.g. freebsd, will do things like have
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// 500mb RLIMIT_STACK by default, even on machines with 400mb RAM
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if (!IsWindows() && !IsXnu()) {
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struct rlimit rl;
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getrlimit(RLIMIT_STACK, &rl);
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rl.rlim_cur = MIN(rl.rlim_cur, 2 * 1024 * 1024);
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ASSERT_SYS(0, 0, setrlimit(RLIMIT_STACK, &rl));
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}
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// set up the signal handler and alternative stack
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struct sigaction sa;
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struct sigaltstack ss;
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ss.ss_flags = 0;
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ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 8192;
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ss.ss_sp = _mapanon(ss.ss_size);
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ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
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sa.sa_flags = SA_SIGINFO | SA_ONSTACK; // <-- important
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sigemptyset(&sa.sa_mask);
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sa.sa_sigaction = CrashHandler;
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sigaction(SIGBUS, &sa, 0);
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sigaction(SIGSEGV, &sa, 0);
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}
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int StackOverflow(int f(), int n) {
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if (n < INT_MAX) {
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return f(f, n + 1) - 1;
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} else {
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return INT_MAX;
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}
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}
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int (*pStackOverflow)(int (*)(), int) = StackOverflow;
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TEST(stackoverflow, standardStack_altStack_process_longjmp) {
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if (IsTiny()) return; // TODO(jart): why?
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int jumpcode;
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if (!(jumpcode = setjmp(recover))) {
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exit(pStackOverflow(pStackOverflow, 0));
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}
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ASSERT_EQ(123, jumpcode);
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ASSERT_TRUE(smashed_stack);
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// here's where longjmp() gets us into trouble
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struct sigaltstack ss;
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ASSERT_SYS(0, 0, sigaltstack(0, &ss));
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if (IsXnu() || IsNetbsd()) {
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ASSERT_EQ(SS_ONSTACK, ss.ss_flags); // wut
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} else {
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ASSERT_EQ(0, ss.ss_flags);
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}
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}
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