Fix some todos

test/libc/calls/clock_nanosleep_test.c

@@ -32,10 +32,6 @@
 #include "libc/testlib/testlib.h"
 #include "libc/time/time.h"
 
-void SetUpOnce(void) {
-  if (!IsWindows()) _Exit(0);
-}
-
 void OnAlrm(int sig) {
   // do nothing
   STRACE("OnAlrm()");

test/libc/calls/stackoverflow1_test.c

@@ -0,0 +1,108 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/rlimit.h"
+#include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/sigaltstack.h"
+#include "libc/calls/struct/siginfo.h"
+#include "libc/dce.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/limits.h"
+#include "libc/mem/gc.internal.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/runtime/sysconf.h"
+#include "libc/sysv/consts/rlimit.h"
+#include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/sysv/consts/ss.h"
+#include "libc/testlib/testlib.h"
+#include "libc/thread/thread.h"
+
+/**
+ * stack overflow recovery technique #1
+ * overflow the gigantic main process stack
+ * simple but it can upset kernels / libraries
+ */
+
+jmp_buf recover;
+volatile bool smashed_stack;
+
+void CrashHandler(int sig, siginfo_t *si, void *ctx) {
+  struct sigaltstack ss;
+  ASSERT_SYS(0, 0, sigaltstack(0, &ss));
+  ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
+  kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
+  smashed_stack = true;
+  ASSERT_TRUE(__is_stack_overflow(si, ctx));
+  longjmp(recover, 123);
+}
+
+void SetUp(void) {
+
+  // tune down the main process's stack size to a reasonable amount
+  // some operating systems, e.g. freebsd, will do things like have
+  // 500mb RLIMIT_STACK by default, even on machines with 400mb RAM
+  struct rlimit rl = {2 * 1024 * 1024, 2 * 1024 * 1024};
+  if (!IsWindows() && !IsXnu()) {
+    ASSERT_SYS(0, 0, setrlimit(RLIMIT_STACK, &rl));
+  }
+
+  // set up the signal handler and alternative stack
+  struct sigaction sa;
+  struct sigaltstack ss;
+  ss.ss_flags = 0;
+  ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 8192;
+  ss.ss_sp = _mapanon(ss.ss_size);
+  ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
+  sa.sa_flags = SA_SIGINFO | SA_ONSTACK;  // <-- important
+  sigemptyset(&sa.sa_mask);
+  sa.sa_sigaction = CrashHandler;
+  sigaction(SIGBUS, &sa, 0);
+  sigaction(SIGSEGV, &sa, 0);
+}
+
+int StackOverflow(int f(), int n) {
+  if (n < INT_MAX) {
+    return f(f, n + 1) - 1;
+  } else {
+    return INT_MAX;
+  }
+}
+
+int (*pStackOverflow)(int (*)(), int) = StackOverflow;
+
+TEST(stackoverflow, standardStack_altStack_process_longjmp) {
+  if (IsTiny()) return;  // TODO(jart): why?
+
+  int jumpcode;
+  if (!(jumpcode = setjmp(recover))) {
+    exit(pStackOverflow(pStackOverflow, 0));
+  }
+  ASSERT_EQ(123, jumpcode);
+  ASSERT_TRUE(smashed_stack);
+
+  // here's where longjmp() gets us into trouble
+  struct sigaltstack ss;
+  ASSERT_SYS(0, 0, sigaltstack(0, &ss));
+  if (IsXnu() || IsNetbsd()) {
+    ASSERT_EQ(SS_ONSTACK, ss.ss_flags);  // wut
+  } else {
+    ASSERT_EQ(0, ss.ss_flags);
+  }
+}

test/libc/calls/stackoverflow2_test.c

@@ -0,0 +1,105 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/sigaltstack.h"
+#include "libc/calls/struct/siginfo.h"
+#include "libc/dce.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/limits.h"
+#include "libc/mem/gc.internal.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/runtime/sysconf.h"
+#include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/sysv/consts/ss.h"
+#include "libc/testlib/testlib.h"
+#include "libc/thread/thread.h"
+
+/**
+ * stack overflow recovery technique #2
+ * longjmp out of signal back into thread
+ * simple but it can upset kernels / libraries
+ */
+
+jmp_buf recover;
+volatile bool smashed_stack;
+
+void CrashHandler(int sig, siginfo_t *si, void *ctx) {
+  struct sigaltstack ss;
+  ASSERT_SYS(0, 0, sigaltstack(0, &ss));
+  ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
+  kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
+  smashed_stack = true;
+  ASSERT_TRUE(__is_stack_overflow(si, ctx));
+  longjmp(recover, 123);
+}
+
+int StackOverflow(int f(), int n) {
+  if (n < INT_MAX) {
+    return f(f, n + 1) - 1;
+  } else {
+    return INT_MAX;
+  }
+}
+
+int (*pStackOverflow)(int (*)(), int) = StackOverflow;
+
+void *MyPosixThread(void *arg) {
+  int jumpcode;
+  struct sigaction sa, o1, o2;
+  struct sigaltstack ss;
+  ss.ss_flags = 0;
+  ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 4096;
+  ss.ss_sp = gc(malloc(ss.ss_size));
+  ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
+  sa.sa_flags = SA_SIGINFO | SA_ONSTACK;  // <-- important
+  sigemptyset(&sa.sa_mask);
+  sa.sa_sigaction = CrashHandler;
+  sigaction(SIGBUS, &sa, &o1);
+  sigaction(SIGSEGV, &sa, &o2);
+  if (!(jumpcode = setjmp(recover))) {
+    exit(pStackOverflow(pStackOverflow, 0));
+  }
+  ASSERT_EQ(123, jumpcode);
+  sigaction(SIGSEGV, &o2, 0);
+  sigaction(SIGBUS, &o1, 0);
+  // here's where longjmp() gets us into trouble
+  ASSERT_SYS(0, 0, sigaltstack(0, &ss));
+  if (IsXnu() || IsNetbsd()) {
+    ASSERT_EQ(SS_ONSTACK, ss.ss_flags);  // wut
+  } else {
+    ASSERT_EQ(0, ss.ss_flags);
+  }
+  return 0;
+}
+
+TEST(stackoverflow, standardStack_altStack_thread_longjmp) {
+  pthread_t th;
+  struct sigaltstack ss;
+  for (int i = 0; i < 2; ++i) {
+    smashed_stack = false;
+    pthread_create(&th, 0, MyPosixThread, 0);
+    pthread_join(th, 0);
+    ASSERT_TRUE(smashed_stack);
+    // this should be SS_DISABLE but ShowCrashReports() creates an alt stack
+    ASSERT_SYS(0, 0, sigaltstack(0, &ss));
+    ASSERT_EQ(0, ss.ss_flags);
+  }
+}

test/libc/thread/makecontext_test.c

@@ -31,10 +31,9 @@
 #include "libc/x/x.h"
 #include "third_party/libcxx/math.h"
 
-#if 0  // TODO(jart): fix me
-
 bool gotsome;
 ucontext_t uc, goback;
+extern long __klog_handle;
 
 void SetUpOnce(void) {
   testlib_enable_tmp_setup_teardown();
@@ -90,18 +89,17 @@ TEST(makecontext, backtrace) {
   SPAWN(fork);
   ASSERT_SYS(0, 0, close(2));
   ASSERT_SYS(0, 2, creat("log", 0644));
+  __klog_handle = 2;
   getcontext(&uc);
   uc.uc_link = 0;
   uc.uc_stack.ss_sp = NewCosmoStack();
   uc.uc_stack.ss_size = GetStackSize();
   makecontext(&uc, itsatrap, 2, 123, 456);
   setcontext(&uc);
-  EXITS(128 + SIGSEGV);
+  TERMS(SIGSEGV);
   if (!GetSymbolTable()) return;
   char *log = gc(xslurp("log", 0));
   EXPECT_NE(0, strstr(log, "itsatrap"));
   EXPECT_NE(0, strstr(log, "runcontext"));
   EXPECT_NE(0, strstr(log, "makecontext_backtrace"));
 }
-
-#endif