Make fixes and improvements

- Invent iso8601us() for faster timestamps
- Improve --strace descriptions of sigset_t
- Rebuild the Landlock Make bootstrap binary
- Introduce MODE=sysv for non-Windows builds
- Permit OFD fcntl() locks under pledge(flock)
- redbean can now protect your kernel from ddos
- Have vfork() fallback to sys_fork() not fork()
- Change kmalloc() to not die when out of memory
- Improve documentation for some termios functions
- Rewrite putenv() and friends to conform to POSIX
- Fix linenoise + strace verbosity issue on Windows
- Fix regressions in our ability to show backtraces
- Change redbean SetHeader() to no-op if value is nil
- Improve fcntl() so SQLite locks work in non-WAL mode
- Remove some unnecessary work during fork() on Windows
- Create redbean-based SSL reverse proxy for IPv4 TurfWar
- Fix ape/apeinstall.sh warning when using non-bash shells
- Add ProgramTrustedIp(), and IsTrustedIp() APIs to redbean
- Support $PWD, $UID, $GID, and $EUID in command interpreter
- Introduce experimental JTqFpD APE prefix for non-Windows builds
- Invent blackhole daemon for firewalling IP addresses via UNIX named socket
- Add ProgramTokenBucket(), AcquireToken(), and CountTokens() APIs to redbean

test/libc/calls/sigaction_test.c

@@ -20,6 +20,7 @@
 #include "libc/calls/struct/rusage.h"
 #include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/siginfo.h"
+#include "libc/calls/struct/sigset.h"
 #include "libc/calls/ucontext.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
@@ -175,3 +176,27 @@ TEST(sigaction, ignoringSignalDiscardsSignal) {
   ASSERT_EQ(0, sigprocmask(SIG_UNBLOCK, &blocked, NULL));
   EXPECT_EQ(0, OnSignalCnt);
 }
+
+TEST(sigaction, autoZombieSlayer) {
+  if (IsWindows()) return;
+  int pid;
+  struct sigaction sa;
+  // make sure we're starting in expected state
+  ASSERT_SYS(0, 0, sigaction(SIGCHLD, 0, &sa));
+  ASSERT_EQ(SIG_DFL, sa.sa_handler);
+  // verify child becomes zombie
+  ASSERT_NE(-1, (pid = fork()));
+  if (!pid) _Exit(0);
+  ASSERT_SYS(0, pid, wait(0));
+  // enable automatic zombie slayer
+  sa.sa_handler = SIG_IGN;
+  sa.sa_flags = SA_NOCLDWAIT;  // seems to be optional
+  sigemptyset(&sa.sa_mask);
+  ASSERT_SYS(0, 0, sigaction(SIGCHLD, &sa, &sa));
+  // verify it works
+  ASSERT_NE(-1, (pid = fork()));
+  if (!pid) _Exit(0);
+  ASSERT_SYS(ECHILD, -1, wait(0));
+  // clean up
+  ASSERT_SYS(0, 0, sigaction(SIGCHLD, &sa, 0));
+}