Add wait4 syscall to Noux, just blocking for now

ports/include/noux_session/noux_session.h

@@ -48,6 +48,7 @@ namespace Noux {
 			SYSCALL_SELECT,
 			SYSCALL_FORK,
 			SYSCALL_GETPID,
+			SYSCALL_WAIT4,
 			SYSCALL_INVALID = -1
 		};
 
@@ -70,6 +71,7 @@ namespace Noux {
 			NOUX_DECL_SYSCALL_NAME(SELECT)
 			NOUX_DECL_SYSCALL_NAME(FORK)
 			NOUX_DECL_SYSCALL_NAME(GETPID)
+			NOUX_DECL_SYSCALL_NAME(WAIT4)
 			case SYSCALL_INVALID: return 0;
 			}
 			return 0;

ports/include/noux_session/sysio.h

@@ -253,6 +253,9 @@ namespace Noux {
 			                   { int pid; });
 
 			SYSIO_DECL(getpid, { }, { int pid; });
+
+			SYSIO_DECL(wait4,  { int pid; bool nohang; },
+			                   { int pid; int status; });
 		};
 	};
 };

ports/src/lib/libc_noux/plugin.cc

@@ -380,19 +380,17 @@ extern "C" pid_t getpid(void)
 extern "C" pid_t _wait4(pid_t pid, int *status, int options,
                         struct rusage *rusage)
 {
-	/*
-	 * XXX dummy to accomodate the 'reap_zombie_children' function in bash
-	 */
-	if (options & WNOHANG) {
-		PWRN("_wait4 dummy called (with WNOHANG) - not implemented");
-		return 0;
+	sysio()->wait4_in.pid    = pid;
+	sysio()->wait4_in.nohang = !!(options & WNOHANG);
+	if (!noux()->syscall(Noux::Session::SYSCALL_WAIT4)) {
+		PERR("wait4 error %d", sysio()->error.general);
+		return -1;
 	}
 
-	PDBG("_wait4 (pid=%d, options=0x%x) called, waiting forever...",
-	      pid, options);
+	if (status)
+		*status = sysio()->wait4_out.status;
 
-	for (;;);
-	return 0;
+	return sysio()->wait4_out.pid;
 }
 
 

ports/src/noux/main.cc

@@ -323,6 +323,24 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 				return true;
 			}
 
+		case SYSCALL_WAIT4:
+			{
+				PINF("SYSCALL_WAIT4 called");
+
+				/*
+				 * XXX check if one of out children exited
+				 */
+
+				if (!_sysio->wait4_in.nohang)
+					_blocker.down();
+
+				_sysio->wait4_out.pid = -1;
+				_sysio->wait4_out.status = 0;
+
+				PINF("SYSCALL_WAIT4 returning");
+				return true;
+			}
+
 		case SYSCALL_INVALID: break;
 		}
 	}