Implement raw system call for redbean lua code

You can now call functions like fork() from Lua and it'll work across
all supported platforms, including Windows. This gives you a level of
control of the system that Lua traditionally hasn't been able to have
due to its focus on old portable stdio rather modern POSIX APIs. Demo
code has been added to redbean-demo.com to show how it works.

This change also modifies Lua so that integer literals with a leading
zero will be interpreted as octal. That should help avoid shooting in
the foot with POSIX APIs that frequently use octal mode bits.

This change fixes a bug in opendir(".") on New Technology.

Lastly, redbean will now serve crash reports to private network IPs.
This is consistent with other frameworks. However that isn't served
to public IPs unless the -E flag is passed to redbean at startup.

libc/calls/calls.h

@@ -229,7 +229,7 @@ uint32_t getgid(void) nosideeffect;
 uint32_t getpgrp(void) nosideeffect;
 uint32_t getsid(int) nosideeffect;
 uint32_t getuid(void) nosideeffect;
-uint32_t umask(int32_t);
+uint32_t umask(uint32_t);
 void rewinddir(DIR *);
 void sync(void);
 int getloadavg(double *, int);

libc/calls/dup3.c

@@ -32,7 +32,7 @@
  * @param oldfd isn't closed afterwards
  * @param newfd if already assigned, is silently closed beforehand;
  *     unless it's equal to oldfd, in which case dup2() is a no-op
- * @flags can have O_CLOEXEC
+ * @param flags can have O_CLOEXEC
  * @see dup(), dup2()
  */
 int dup3(int oldfd, int newfd, int flags) {

libc/calls/getppid.c

@@ -17,19 +17,23 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/internal.h"
+#include "libc/calls/strace.internal.h"
 
 /**
  * Returns parent process id.
  * @asyncsignalsafe
  */
 int getppid(void) {
+  int rc;
   if (!IsWindows()) {
     if (!IsNetbsd()) {
-      return sys_getppid();
+      rc = sys_getppid();
     } else {
-      return sys_getpid().dx;
+      rc = sys_getpid().dx;
     }
   } else {
-    return sys_getppid_nt();
+    rc = sys_getppid_nt();
   }
+  STRACE("getppid() → %d% m", rc);
+  return rc;
 }

libc/calls/getpriority.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
+#include "libc/calls/strace.internal.h"
 
 /**
  * Returns nice value of thing.
@@ -28,9 +29,12 @@
  * @see setpriority(), nice()
  */
 int getpriority(int which, unsigned who) {
+  int rc;
   if (!IsWindows()) {
-    return sys_getpriority(which, who) - 20;
+    rc = sys_getpriority(which, who) - 20;
   } else {
-    return sys_getsetpriority_nt(which, who, 0, sys_getpriority_nt);
+    rc = sys_getsetpriority_nt(which, who, 0, sys_getpriority_nt);
   }
+  STRACE("getpriority(%d, %u) → %d% m", which, who, rc);
+  return rc;
 }

libc/calls/internal.h

@@ -220,6 +220,7 @@ u32 sys_getgid(void) hidden;
 u32 sys_getsid(int) hidden;
 u32 sys_gettid(void) hidden;
 u32 sys_getuid(void) hidden;
+u32 sys_umask(u32) hidden;
 void *__sys_mmap(void *, u64, u32, u32, i64, i64, i64) hidden;
 void *sys_mremap(void *, u64, u64, i32, void *) hidden;
 void sys_exit(int) hidden;

libc/calls/setegid.c

@@ -17,10 +17,14 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
+#include "libc/calls/strace.internal.h"
 
 /**
  * Sets effective group ID.
  */
-int setegid(unsigned gid) {
-  return setregid(-1, gid);
+int setegid(unsigned egid) {
+  int rc;
+  rc = setregid(-1, egid);
+  STRACE("%s(%u) → %d% m", "setegid", egid, rc);
+  return rc;
 }

libc/calls/seteuid.c

@@ -17,10 +17,14 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
+#include "libc/calls/strace.internal.h"
 
 /**
  * Sets effective user ID.
  */
 int seteuid(unsigned euid) {
-  return setreuid(-1, euid);
+  int rc;
+  rc = setreuid(-1, euid);
+  STRACE("%s(%u) → %d% m", "seteuid", euid, rc);
+  return rc;
 }

libc/calls/setsid.c

@@ -18,10 +18,15 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
+#include "libc/calls/strace.internal.h"
 
 /**
  * Creates session and sets the process group id.
+ * @return new session id, or -1 w/ errno
  */
 int setsid(void) {
-  return sys_setsid();
+  int rc;
+  rc = sys_setsid();
+  STRACE("setsid() → %d% m", rc);
+  return rc;
 }

libc/calls/umask.c

@@ -0,0 +1,40 @@
+/*-*- 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 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/calls/calls.h"
+#include "libc/calls/internal.h"
+#include "libc/calls/strace.internal.h"
+#include "libc/dce.h"
+
+/**
+ * Sets file mode creation mask.
+ *
+ * @return previous mask
+ * @note always succeeds
+ */
+unsigned umask(unsigned newmask) {
+  unsigned oldmask;
+  if (!IsWindows()) {
+    oldmask = sys_umask(newmask);
+  } else {
+    // TODO(jart): what should we do with this?
+    oldmask = newmask;
+  }
+  STRACE("umask(%#o) → %#o", oldmask);
+  return oldmask;
+}