Greatly expand system() shell code features

The cosmopolitan command interpreter now has 13 builtin commands,
variable support, support for ; / && / || syntax, asynchronous support,
and plenty of unit tests with bug fixes.

This change fixes a bug in posix_spawn() with null envp arg. strace
logging now uses atomic writes for scatter functions. Breaking change
renaming GetCpuCount() to _getcpucount(). TurfWar is now updated to use
the new token bucket algorithm. WIN32 affinity masks now inherit across
fork() and execve().

libc/runtime/daemon.c

@@ -16,39 +16,51 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
 #include "libc/calls/calls.h"
+#include "libc/calls/syscall_support-sysv.internal.h"
+#include "libc/dce.h"
+#include "libc/nt/enum/processcreationflags.h"
 #include "libc/paths.h"
+#include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/o.h"
 
 /**
- * Daemonizes process.
+ * Runs process in background.
+ *
+ * On Unix this calls fork() and setsid(). On Windows this is
+ * implemented using CreateProcess(kNtDetachedProcess).
+ *
+ * @return 0 on success, or -1 w/ errno
  */
 int daemon(int nochdir, int noclose) {
   int fd;
 
-  switch (fork()) {
+  switch (_fork(kNtDetachedProcess)) {
     case -1:
-      return (-1);
+      return -1;
     case 0:
       break;
     default:
       _Exit(0);
   }
 
-  if (setsid() == -1) {
-    return -1;
+  if (!IsWindows()) {
+    if (setsid() == -1) {
+      return -1;
+    }
   }
 
   if (!nochdir) {
-    chdir("/");
+    _unassert(!chdir("/"));
   }
 
   if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
-    dup2(fd, 0);
-    dup2(fd, 1);
-    dup2(fd, 2);
+    _unassert(dup2(fd, 0) == 0);
+    _unassert(dup2(fd, 1) == 1);
+    _unassert(dup2(fd, 2) == 2);
     if (fd > 2) {
-      close(fd);
+      _unassert(!close(fd));
     }
   }
 

libc/runtime/fork-nt.c

@@ -19,6 +19,7 @@
 #include "libc/calls/internal.h"
 #include "libc/calls/ntspawn.h"
 #include "libc/calls/state.internal.h"
+#include "libc/calls/syscall-nt.internal.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/calls/wincrash.internal.h"
 #include "libc/errno.h"
@@ -260,7 +261,7 @@ textwindows void WinMainForked(void) {
   longjmp(jb, 1);
 }
 
-textwindows int sys_fork_nt(void) {
+textwindows int sys_fork_nt(uint32_t dwCreationFlags) {
   bool ok;
   jmp_buf jb;
   uint32_t oldprot;
@@ -302,7 +303,7 @@ textwindows int sys_fork_nt(void) {
       }
 #endif
       if (ntspawn(GetProgramExecutableName(), args, environ, forkvar, 0, 0,
-                  true, 0, 0, &startinfo, &procinfo) != -1) {
+                  true, dwCreationFlags, 0, &startinfo, &procinfo) != -1) {
         CloseHandle(procinfo.hThread);
         ok = WriteAll(writer, jb, sizeof(jb)) &&
              WriteAll(writer, &_mmi.i, sizeof(_mmi.i)) &&

libc/runtime/fork.c

@@ -21,6 +21,7 @@
 #include "libc/calls/struct/sigset.internal.h"
 #include "libc/calls/syscall-nt.internal.h"
 #include "libc/calls/syscall-sysv.internal.h"
+#include "libc/calls/syscall_support-sysv.internal.h"
 #include "libc/dce.h"
 #include "libc/intrin/strace.internal.h"
 #include "libc/nt/process.h"
@@ -28,15 +29,7 @@
 #include "libc/sysv/consts/sig.h"
 #include "libc/thread/tls.h"
 
-/**
- * Creates new process.
- *
- * @return 0 to child, child pid to parent, or -1 w/ errno
- * @raise EAGAIN if `RLIMIT_NPROC` was exceeded or system lacked resources
- * @raise ENOMEM if we require more vespene gas
- * @asyncsignalsafe
- */
-int fork(void) {
+int _fork(uint32_t dwCreationFlags) {
   axdx_t ad;
   sigset_t old, all;
   int ax, dx, parent;
@@ -52,7 +45,7 @@ int fork(void) {
       ax &= dx - 1;
     }
   } else {
-    ax = sys_fork_nt();
+    ax = sys_fork_nt(dwCreationFlags);
   }
   if (!ax) {
     if (!IsWindows()) {
@@ -73,3 +66,15 @@ int fork(void) {
   }
   return ax;
 }
+
+/**
+ * Creates new process.
+ *
+ * @return 0 to child, child pid to parent, or -1 w/ errno
+ * @raise EAGAIN if `RLIMIT_NPROC` was exceeded or system lacked resources
+ * @raise ENOMEM if we require more vespene gas
+ * @asyncsignalsafe
+ */
+int fork(void) {
+  return _fork(0);
+}

libc/runtime/runtime.h

@@ -103,6 +103,7 @@ void _intsort(int *, size_t);
 void _longsort(long *, size_t);
 bool _isheap(void *);
 int NtGetVersion(void) pureconst;
+unsigned _getcpucount(void) pureconst;
 long _missingno();
 void __oom_hook(size_t);
 void _loadxmm(void *);

libc/runtime/sysconf.c

@@ -49,7 +49,7 @@ long sysconf(int name) {
     case _SC_PAGESIZE:
       return FRAMESIZE;
     case _SC_NPROCESSORS_ONLN:
-      n = GetCpuCount();
+      n = _getcpucount();
       return n > 0 ? n : -1;
     default:
       return -1;

libc/runtime/sysconf.h

@@ -147,7 +147,6 @@
 COSMOPOLITAN_C_START_
 
 long sysconf(int);
-unsigned GetCpuCount(void);
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

libc/runtime/vfork.S

@@ -35,7 +35,7 @@
 //	@return	pid of child process or 0 if forked process
 //	@returnstwice
 //	@vforksafe
-vfork:
+vfork:	xor	%edi,%edi		# dwCreationFlags
 #ifdef __SANITIZE_ADDRESS__
 	jmp	fork			# TODO: asan and vfork don't mix?
 	.endfn	vfork,globl