Show crash reports on SIGSYS

This will help make it easier to troubleshoot ABI breakages with on
operating systems that, unlike Linux don't have ironclad guarantees
to not break userspace.

libc/calls/syscall_support-sysv.internal.h

@@ -12,6 +12,7 @@ int __notziposat(int, const char *);
 int gethostname_bsd(char *, size_t) hidden;
 int gethostname_linux(char *, size_t) hidden;
 int gethostname_nt(char *, size_t, int) hidden;
+long sys_bogus(void);
 void *__vdsosym(const char *, const char *) hidden;
 void __onfork(void) hidden;
 void __restore_rt() hidden;

libc/log/getsicodename.c

@@ -16,6 +16,7 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/fmt/itoa.h"
 #include "libc/log/log.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/sicode.h"
@@ -29,13 +30,17 @@ static bool IsSiUser(int si_code) {
   }
 }
 
+static void NameIt(char p[17], const char *s, int si_code) {
+  p = stpcpy(p, s);
+  FormatInt32(p, si_code);
+}
+
 /**
  * Returns symbolic name for siginfo::si_code value.
  */
 const char *GetSiCodeName(int sig, int si_code) {
-  static char b[16];
-  bzero(b, sizeof(b));
-  strcpy(b, "SI_???");
+  static char b[17];
+  NameIt(b, "SI_", si_code);
   if (si_code == SI_QUEUE) {
     strcpy(b + 3, "QUEUE"); /* sent by sigqueue(2) */
   } else if (si_code == SI_TIMER) {
@@ -55,7 +60,7 @@ const char *GetSiCodeName(int sig, int si_code) {
   } else if (IsSiUser(si_code)) {
     strcpy(b + 3, "USER"); /* sent by kill(2) i.e. from userspace */
   } else if (sig == SIGCHLD) {
-    strcpy(b, "CLD_???");
+    NameIt(b, "CLD_", si_code);
     if (si_code == CLD_EXITED) {
       strcpy(b + 4, "EXITED"); /* child exited */
     } else if (si_code == CLD_KILLED) {
@@ -70,14 +75,14 @@ const char *GetSiCodeName(int sig, int si_code) {
       strcpy(b + 4, "CONTINUED"); /* stopped child continued */
     }
   } else if (sig == SIGTRAP) {
-    strcpy(b, "TRAP_???");
+    NameIt(b, "TRAP_", si_code);
     if (si_code == TRAP_BRKPT) {
       strcpy(b + 5, "BRKPT"); /* process breakpoint */
     } else if (si_code == TRAP_TRACE) {
       strcpy(b + 5, "TRACE"); /* process trace trap */
     }
   } else if (sig == SIGSEGV) {
-    strcpy(b, "SEGV_???");
+    NameIt(b, "SEGV_", si_code);
     if (si_code == SEGV_MAPERR) {
       strcpy(b + 5, "MAPERR"); /* address not mapped to object */
     } else if (si_code == SEGV_ACCERR) {
@@ -86,7 +91,7 @@ const char *GetSiCodeName(int sig, int si_code) {
       strcpy(b + 5, "PKUERR"); /* FreeBSD: x86: PKU violation */
     }
   } else if (sig == SIGFPE) {
-    strcpy(b, "FPE_???");
+    NameIt(b, "FPE_???", si_code);
     if (si_code == FPE_INTDIV) {
       strcpy(b + 4, "INTDIV"); /* integer divide by zero */
     } else if (si_code == FPE_INTOVF) {
@@ -105,7 +110,7 @@ const char *GetSiCodeName(int sig, int si_code) {
       strcpy(b + 4, "FLTSUB"); /* subscript out of range */
     }
   } else if (sig == SIGILL) {
-    strcpy(b, "ILL_???");
+    NameIt(b, "ILL_", si_code);
     if (si_code == ILL_ILLOPC) {
       strcpy(b + 4, "ILLOPC"); /* illegal opcode */
     } else if (si_code == ILL_ILLOPN) {
@@ -124,7 +129,7 @@ const char *GetSiCodeName(int sig, int si_code) {
       strcpy(b + 4, "BADSTK"); /* internal stack error */
     }
   } else if (sig == SIGBUS) {
-    strcpy(b, "BUS_???");
+    NameIt(b, "BUS_", si_code);
     if (si_code == BUS_ADRALN) {
       strcpy(b + 4, "ADRALN"); /* invalid address alignment */
     } else if (si_code == BUS_ADRERR) {
@@ -139,7 +144,7 @@ const char *GetSiCodeName(int sig, int si_code) {
       strcpy(b + 4, "MCEERR_AO"); /* Linux 2.6.32+ */
     }
   } else if (sig == SIGIO) {
-    strcpy(b, "POLL_???");
+    NameIt(b, "POLL_", si_code);
     if (si_code == POLL_IN) {
       strcpy(b + 5, "IN"); /* data input available */
     } else if (si_code == POLL_OUT) {

libc/log/internal.h

@@ -8,7 +8,7 @@
 COSMOPOLITAN_C_START_
 
 extern hidden bool __nocolor;
-extern hidden int kCrashSigs[7];
+extern hidden int kCrashSigs[8];
 extern hidden bool g_isrunningundermake;
 
 void __start_fatal(const char *, int) hidden;

libc/log/oncrash.c

@@ -58,7 +58,7 @@ static const char kGregNames[17][4] forcealign(1) = {
 static const char kCpuFlags[12] forcealign(1) = "CVPRAKZSTIDO";
 static const char kFpuExceptions[6] forcealign(1) = "IDZOUP";
 
-int kCrashSigs[7];
+int kCrashSigs[8];
 
 relegated static void ShowFunctionCalls(ucontext_t *ctx) {
   struct StackFrame *bp;

libc/log/oncrashthunks.S

@@ -24,7 +24,7 @@
 
 __oncrash_thunks:
 
-//	<SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c
+//	<SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c, internal.h
 
 	.org	11*0
 __oncrash_sigquit:
@@ -89,6 +89,15 @@ __oncrash_sigbus:
 	ret
 	.endfn	__oncrash_sigbus,globl
 
-//	</SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c
+	.org	11*7
+__oncrash_sigsys:
+	push	%rbp
+	mov	%rsp,%rbp
+	call	__oncrash
+	pop	%rbp
+	ret
+	.endfn	__oncrash_sigsys,globl
+
+//	</SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c, internal.h
 
 	.endobj	__oncrash_thunks,globl

libc/log/showcrashreports.c

@@ -39,7 +39,7 @@ STATIC_YOINK("__get_symbol_by_addr");        // for asan memory origin
 
 extern const unsigned char __oncrash_thunks[8][11];
 static struct sigaltstack g_oldsigaltstack;
-static struct sigaction g_oldcrashacts[7];
+static struct sigaction g_oldcrashacts[8];
 
 static void InstallCrashHandlers(int extraflags) {
   size_t i;
@@ -104,6 +104,7 @@ void ShowCrashReports(void) {
   kCrashSigs[4] = SIGTRAP; /* bad system call */
   kCrashSigs[5] = SIGABRT; /* abort() called */
   kCrashSigs[6] = SIGBUS;  /* misaligned, noncanonical ptr, etc. */
+  kCrashSigs[7] = SIGSYS;  /* bad system call */
   /* </SYNC-LIST>: showcrashreports.c, oncrashthunks.S, oncrash.c */
   if (!IsWindows()) {
     bzero(&ss, sizeof(ss));

libc/log/showcrashreportsearly.S

@@ -0,0 +1,35 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 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/macros.internal.h"
+
+//	Normally we call ShowCrashReports() from main, but if
+//	there's a crash in a constructor, this will help with
+//	troubleshooting it. You need to add:
+//
+//	    STATIC_YOINK("ShowCrashReportsEarly");
+//
+//	To the top of your main module to use this.
+
+	.init.start 400,ShowCrashReportsEarly
+	push	%rdi
+	push	%rsi
+	call	ShowCrashReports
+	pop	%rsi
+	pop	%rdi
+	.init.end 400,ShowCrashReportsEarly

libc/sysv/calls/sys_bogus.s

@@ -0,0 +1,2 @@
+.include "o/libc/sysv/macros.internal.inc"
+.scall sys_bogus,0x5005005002500500,globl

libc/sysv/syscalls.sh

@@ -375,6 +375,7 @@ scall	io_uring_register	0xfffffffffffff1ab	globl
 #────────────────────────RHEL CLOUD────────────────────────── # ←┬─ red hat terminates community release of enterprise linux circa 2020
 scall	sys_pledge		0xfff06cffffffffff	globl #  └─ online linux services ban the president of united states of america
 scall	msyscall		0xfff025ffffffffff	globl
+scall	sys_bogus		0x5005005002500500	globl
 
 #	The Fifth Bell System Interface, Community Edition
 #	» besiyata dishmaya

libc/sysv/systemfive.S

@@ -164,8 +164,17 @@ systemfive_bsdscrub:
 systemfive_bsd:
 	cmp	$0xfff,%ax
 	je	systemfive_enosys
-	mov	%rcx,%r10		# note: we do not create a stack frame
+	mov	%rcx,%r10
+	push	%rbx
+	push	32(%rsp)
+	push	24(%rsp)
+	push	16(%rsp)
+	mov	%rax,%rbx		# save ordinal for SIGSYS crash report
 	syscall				# bsd will need arg on stack sometimes
+	pop	%rbx
+	pop	%rbx
+	pop	%rbx
+	pop	%rbx
 	jc	systemfive_errno	# bsd sets carry flag if %rax is errno
 	ret
 	.endfn	systemfive_bsd

tool/net/redbean.c

@@ -29,6 +29,7 @@
 #include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/stat.h"
 #include "libc/calls/struct/termios.h"
+#include "libc/dce.h"
 #include "libc/dns/dns.h"
 #include "libc/dns/hoststxt.h"
 #include "libc/dos.h"
@@ -114,6 +115,9 @@
 
 STATIC_STACK_SIZE(0x40000);
 STATIC_YOINK("zip_uri_support");
+#if !IsTiny()
+STATIC_YOINK("ShowCrashReportsEarly");
+#endif
 
 /**
  * @fileoverview redbean - single-file distributable web server
@@ -7310,9 +7314,6 @@ void RedBean(int argc, char *argv[]) {
 
 int main(int argc, char *argv[]) {
   LoadZipArgs(&argc, &argv);
-  if (!IsTiny()) {
-    ShowCrashReports();
-  }
   RedBean(argc, argv);
   if (IsModeDbg()) {
     CheckForMemoryLeaks();