Overhaul process spawning

libc/log/die.c

@@ -16,20 +16,18 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/atomic.h"
 #include "libc/calls/calls.h"
-#include "libc/calls/state.internal.h"
 #include "libc/calls/syscall-sysv.internal.h"
 #include "libc/dce.h"
-#include "libc/intrin/atomic.h"
+#include "libc/errno.h"
+#include "libc/intrin/describebacktrace.internal.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/log/backtrace.internal.h"
 #include "libc/log/internal.h"
-#include "libc/log/libfatal.internal.h"
 #include "libc/log/log.h"
 #include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
-#include "libc/thread/thread.h"
+#include "libc/str/str.h"
 
 #if SupportsMetal()
 __static_yoink("_idt");
@@ -37,29 +35,18 @@ __static_yoink("_idt");
 
 /**
  * Aborts process after printing a backtrace.
- *
- * If a debugger is present then this will trigger a breakpoint.
  */
-relegated wontreturn void __die(void) {
-  /* asan runtime depends on this function */
-  int me, owner;
-  static atomic_int once;
-  owner = 0;
-  me = __tls_enabled ? __get_tls()->tib_tid : sys_gettid();
-  pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, 0);
-  if (__vforked ||
-      atomic_compare_exchange_strong_explicit(
-          &once, &owner, me, memory_order_relaxed, memory_order_relaxed)) {
-    __restore_tty();
-    if (IsDebuggerPresent(false)) {
-      DebugBreak();
-    }
-    ShowBacktrace(2, __builtin_frame_address(0));
-    _Exit(77);
-  } else if (owner == me) {
-    kprintf("die failed while dying\n");
-    _Exit(79);
-  } else {
-    _Exit1(79);
-  }
+relegated dontasan wontreturn void __die(void) {
+
+  // print vital error nubers reliably
+  // the surface are of code this calls is small and audited
+  kprintf("\r\n\e[1;31m__die %s pid %d tid %d bt %s\e[0m\n",
+          program_invocation_short_name, getpid(), sys_gettid(),
+          DescribeBacktrace(__builtin_frame_address(0)));
+
+  // print much friendlier backtrace less reliably
+  // we're in a broken runtime state and so much can go wrong
+  __restore_tty();
+  ShowBacktrace(2, __builtin_frame_address(0));
+  _Exit(77);
 }

libc/log/libfatal.internal.h

@@ -9,6 +9,12 @@
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
+__funline unsigned long __strlen(const char *s) {
+  unsigned long n = 0;
+  while (*s++) ++n;
+  return n;
+}
+
 __funline int __strcmp(const char *l, const char *r) {
   size_t i = 0;
   while (l[i] == r[i] && r[i]) ++i;
@@ -24,6 +30,15 @@ __funline char *__stpcpy(char *d, const char *s) {
   }
 }
 
+__funline long __write_linux(int fd, const void *p, long n) {
+  long ax = 1;
+  asm volatile("syscall"
+               : "+a"(ax)
+               : "D"(fd), "S"(p), "d"(n)
+               : "rcx", "r11", "memory");
+  return ax;
+}
+
 __funline void *__repstosb(void *di, char al, size_t cx) {
 #if defined(__x86__) && defined(__GNUC__) && !defined(__STRICT_ANSI__)
   asm("rep stosb"

libc/log/oncrash_amd64.c

@@ -21,6 +21,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/state.internal.h"
 #include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/sigset.h"
 #include "libc/calls/struct/utsname.h"
 #include "libc/calls/syscall-sysv.internal.h"
 #include "libc/calls/ucontext.h"
@@ -29,6 +30,7 @@
 #include "libc/fmt/itoa.h"
 #include "libc/intrin/asan.internal.h"
 #include "libc/intrin/atomic.h"
+#include "libc/intrin/describebacktrace.internal.h"
 #include "libc/intrin/describeflags.internal.h"
 #include "libc/intrin/kmalloc.h"
 #include "libc/intrin/kprintf.h"
@@ -259,113 +261,42 @@ relegated void ShowCrashReport(int err, int sig, struct siginfo *si,
   kprintf("\n");
 }
 
-static wontreturn relegated dontinstrument void __minicrash(int sig,
-                                                            struct siginfo *si,
-                                                            ucontext_t *ctx,
-                                                            const char *kind) {
-  kprintf("\n"
-          "\n"
-          "CRASHED %s WITH %G\n"
-          "%s\n"
-          "RIP %x\n"
-          "RSP %x\n"
-          "RBP %x\n"
-          "PID %d\n"
-          "TID %d\n"
-          "\n",
-          kind, sig, __argv[0], ctx ? ctx->uc_mcontext.rip : 0,
-          ctx ? ctx->uc_mcontext.rsp : 0, ctx ? ctx->uc_mcontext.rbp : 0, __pid,
-          __tls_enabled ? __get_tls()->tib_tid : sys_gettid());
-  _Exit(119);
+static relegated wontreturn void RaiseCrash(int sig) {
+  sigset_t ss;
+  sigfillset(&ss);
+  sigdelset(&ss, sig);
+  sigprocmask(SIG_SETMASK, &ss, 0);
+  signal(sig, SIG_DFL);
+  kill(getpid(), sig);
+  _Exit(128 + sig);
 }
 
-/**
- * Crashes in a developer-friendly human-centric way.
- *
- * We first try to launch GDB if it's an interactive development
- * session. Otherwise we show a really good crash report, sort of like
- * Python, that includes filenames and line numbers. Many editors, e.g.
- * Emacs, will even recognize its syntax for quick hopping to the
- * failing line. That's only possible if the the .com.dbg file is in the
- * same folder. If the concomitant debug binary can't be found, we
- * simply print addresses which may be cross-referenced using objdump.
- *
- * This function never returns, except for traps w/ human supervision.
- *
- * @threadsafe
- * @vforksafe
- */
 relegated void __oncrash_amd64(int sig, struct siginfo *si, void *arg) {
-  int bZero;
-#ifdef ATTACH_GDB_ON_CRASH
-  intptr_t rip;
-#endif
-  int me, owner;
   int gdbpid, err;
   ucontext_t *ctx = arg;
-  static atomic_int once;
-  static atomic_int once2;
-  STRACE("__oncrash rip %x", ctx->uc_mcontext.rip);
+
+  // print vital error nubers reliably
+  // the surface are of code this calls is small and audited
+  kprintf(
+      "\r\n\e[1;31m__oncrash %G %s pid %d tid %d rip %x bt %s\e[0m\n", sig,
+      program_invocation_short_name, getpid(), sys_gettid(),
+      ctx ? ctx->uc_mcontext.rip : 0,
+      DescribeBacktrace(ctx ? (struct StackFrame *)ctx->uc_mcontext.rbp
+                            : (struct StackFrame *)__builtin_frame_address(0)));
+
+  // print friendlier detailed crash report less reliably
+  // we're in a broken runtime state and so much can go wrong
   ftrace_enabled(-1);
   strace_enabled(-1);
-  owner = 0;
-  me = __tls_enabled ? __get_tls()->tib_tid : sys_gettid();
-  pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, 0);
-  if (atomic_compare_exchange_strong_explicit(
-          &once, &owner, me, memory_order_relaxed, memory_order_relaxed)) {
-    if (!__vforked) {
-#ifdef ATTACH_GDB_ON_CRASH
-      rip = ctx ? ctx->uc_mcontext.rip : 0;
-#endif
-      err = errno;
-      if ((gdbpid = IsDebuggerPresent(true))) {
-        DebugBreak();
-      } else if (__nocolor || g_isrunningundermake) {
-        gdbpid = -1;
-#if ATTACH_GDB_ON_CRASH
-      } else if (!IsTiny() && IsLinux() && FindDebugBinary() && !__isworker) {
-        // RestoreDefaultCrashSignalHandlers();
-        gdbpid = AttachDebugger(
-            ((sig == SIGTRAP || sig == SIGQUIT) &&
-             (rip >= (intptr_t)&__executable_start && rip < (intptr_t)&_etext))
-                ? rip
-                : 0);
-#endif
-      }
-      if (!(gdbpid > 0 && (sig == SIGTRAP || sig == SIGQUIT))) {
-        __restore_tty();
-        ShowCrashReport(err, sig, si, ctx);
-        _Exit(128 + sig);
-      }
-      atomic_store_explicit(&once, 0, memory_order_relaxed);
-    } else {
-      atomic_store_explicit(&once, 0, memory_order_relaxed);
-      __minicrash(sig, si, ctx, "WHILE VFORKED");
-    }
-  } else if (sig == SIGTRAP) {
-    // chances are IsDebuggerPresent() confused strace w/ gdb
-    goto ItsATrap;
-  } else if (owner == me) {
-    // we crashed while generating a crash report
-    bZero = false;
-    if (atomic_compare_exchange_strong_explicit(
-            &once2, &bZero, true, memory_order_relaxed, memory_order_relaxed)) {
-      __minicrash(sig, si, ctx, "WHILE CRASHING");
-    } else {
-      // somehow __minicrash() crashed not possible
-      for (;;) {
-        abort();
-      }
-    }
-  } else {
-    // multiple threads have crashed
-    // kill current thread assuming process dies soon
-    // TODO(jart): It'd be nice to report on all threads.
-    _Exit1(8);
+  err = errno;
+  if ((gdbpid = IsDebuggerPresent(true))) {
+    DebugBreak();
+  }
+  if (!(gdbpid > 0 && (sig == SIGTRAP || sig == SIGQUIT))) {
+    __restore_tty();
+    ShowCrashReport(err, sig, si, ctx);
+    RaiseCrash(sig);
   }
-ItsATrap:
-  strace_enabled(+1);
-  ftrace_enabled(+1);
 }
 
 #endif /* __x86_64__ */

libc/log/oncrash_arm64.c

@@ -21,6 +21,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/struct/aarch64.internal.h"
 #include "libc/calls/struct/rusage.internal.h"
+#include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/siginfo.h"
 #include "libc/calls/struct/sigset.h"
 #include "libc/calls/struct/sigset.internal.h"
@@ -63,18 +64,28 @@ struct Buffer {
   int i;
 };
 
-static bool IsCode(uintptr_t p) {
+static relegated bool IsCode(uintptr_t p) {
   return __executable_start <= (uint8_t *)p && (uint8_t *)p < _etext;
 }
 
-static void Append(struct Buffer *b, const char *fmt, ...) {
+static relegated void Append(struct Buffer *b, const char *fmt, ...) {
   va_list va;
   va_start(va, fmt);
   b->i += kvsnprintf(b->p + b->i, b->n - b->i, fmt, va);
   va_end(va);
 }
 
-static const char *ColorRegister(int r) {
+static relegated wontreturn void RaiseCrash(int sig) {
+  sigset_t ss;
+  sigfillset(&ss);
+  sigdelset(&ss, sig);
+  sigprocmask(SIG_SETMASK, &ss, 0);
+  signal(sig, SIG_DFL);
+  kill(getpid(), sig);
+  _Exit(128 + sig);
+}
+
+static relegated const char *ColorRegister(int r) {
   if (__nocolor) return "";
   switch (r) {
     case 0:  // arg / res
@@ -115,8 +126,8 @@ static const char *ColorRegister(int r) {
   }
 }
 
-static bool AppendFileLine(struct Buffer *b, const char *addr2line,
-                           const char *debugbin, long addr) {
+static relegated bool AppendFileLine(struct Buffer *b, const char *addr2line,
+                                     const char *debugbin, long addr) {
   ssize_t rc;
   char *p, *q, buf[128];
   int j, k, ws, pid, pfd[2];
@@ -167,8 +178,8 @@ static bool AppendFileLine(struct Buffer *b, const char *addr2line,
   }
 }
 
-static char *GetSymbolName(struct SymbolTable *st, int symbol, char **mem,
-                           size_t *memsz) {
+static relegated char *GetSymbolName(struct SymbolTable *st, int symbol,
+                                     char **mem, size_t *memsz) {
   char *s, *t;
   if ((s = __get_symbol_name(st, symbol)) &&  //
       s[0] == '_' && s[1] == 'Z' &&           //
@@ -348,7 +359,7 @@ relegated void __oncrash_arm64(int sig, struct siginfo *si, void *arg) {
   }
   sys_write(2, b->p, MIN(b->i, b->n));
   __print_maps();
-  _Exit(128 + sig);
+  RaiseCrash(sig);
 }
 
 #endif /* __aarch64__ */

libc/log/showcrashreports.c

@@ -97,7 +97,7 @@ static void RemoveCrashHandler(void *arg) {
   strace_enabled(+1);
 }
 
-static void InstallCrashHandler(int sig, sigaction_f thunk, int extraflags) {
+static void InstallCrashHandler(int sig, sigaction_f thunk) {
   int e;
   struct sigaction sa;
   struct CrashHandler *ch;
@@ -114,7 +114,7 @@ static void InstallCrashHandler(int sig, sigaction_f thunk, int extraflags) {
     sigdelset(&sa.sa_mask, SIGABRT);
     sigdelset(&sa.sa_mask, SIGBUS);
     sigdelset(&sa.sa_mask, SIGURG);
-    sa.sa_flags = SA_SIGINFO | SA_NODEFER | extraflags;
+    sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
     if (!sigaction(sig, &sa, &ch->old)) {
       __cxa_atexit(RemoveCrashHandler, ch, 0);
     }
@@ -138,24 +138,21 @@ static void InstallCrashHandler(int sig, sigaction_f thunk, int extraflags) {
  * useful, for example, if a program is caught in an infinite loop.
  */
 void ShowCrashReports(void) {
-  int ef = 0;
-  struct sigaltstack ss;
-  _wantcrashreports = true;
   if (!IsWindows()) {
-    ef = SA_ONSTACK;
+    struct sigaltstack ss;
     ss.ss_flags = 0;
-    ss.ss_size = GetStackSize();
-    // FreeBSD sigaltstack() will EFAULT if we use MAP_STACK here
-    // OpenBSD sigaltstack() auto-applies MAP_STACK to the memory
-    npassert((ss.ss_sp = _mapanon(GetStackSize())));
-    npassert(!sigaltstack(&ss, 0));
+    ss.ss_size = SIGSTKSZ;
+    ss.ss_sp = malloc(SIGSTKSZ);
+    sigaltstack(&ss, 0);
+    __cxa_atexit(free, ss.ss_sp, 0);
   }
-  InstallCrashHandler(SIGQUIT, __got_sigquit, ef);  // ctrl+\ aka ctrl+break
-  InstallCrashHandler(SIGFPE, __got_sigfpe, ef);    // 1 / 0
-  InstallCrashHandler(SIGILL, __got_sigill, ef);    // illegal instruction
-  InstallCrashHandler(SIGSEGV, __got_sigsegv, ef);  // bad memory access
-  InstallCrashHandler(SIGTRAP, __got_sigtrap, ef);  // bad system call
-  InstallCrashHandler(SIGBUS, __got_sigbus, ef);    // misalign, mmap i/o failed
-  InstallCrashHandler(SIGURG, __got_sigurg, ef);    // placeholder
+  InstallCrashHandler(SIGQUIT, __got_sigquit);  // ctrl+\ aka ctrl+break
+  InstallCrashHandler(SIGFPE, __got_sigfpe);    // 1 / 0
+  InstallCrashHandler(SIGILL, __got_sigill);    // illegal instruction
+  InstallCrashHandler(SIGSEGV, __got_sigsegv);  // bad memory access
+  InstallCrashHandler(SIGTRAP, __got_sigtrap);  // bad system call
+  InstallCrashHandler(SIGBUS, __got_sigbus);    // misalign, mmap i/o failed
+  InstallCrashHandler(SIGURG, __got_sigurg);    // placeholder
+  _wantcrashreports = true;
   GetSymbolTable();
 }