noux: getdtablesize support

Fixes #1847

repos/ports/include/noux_session/noux_session.h

@@ -85,6 +85,7 @@ namespace Noux {
 			SYSCALL_UTIMES,
 			SYSCALL_SYNC,
 			SYSCALL_KILL,
+			SYSCALL_GETDTABLESIZE,
 			SYSCALL_INVALID = -1
 		};
 
@@ -134,6 +135,7 @@ namespace Noux {
 			NOUX_DECL_SYSCALL_NAME(UTIMES)
 			NOUX_DECL_SYSCALL_NAME(SYNC)
 			NOUX_DECL_SYSCALL_NAME(KILL)
+			NOUX_DECL_SYSCALL_NAME(GETDTABLESIZE)
 			case SYSCALL_INVALID: return 0;
 			}
 			return 0;

repos/ports/include/noux_session/sysio.h

@@ -459,6 +459,8 @@ namespace Noux {
 			SYSIO_DECL(sync,        { }, { });
 
 			SYSIO_DECL(kill,        { int pid; Signal sig; }, { });
+
+			SYSIO_DECL(getdtablesize, { }, { int n; });
 		};
 	};
 };

repos/ports/src/lib/libc_noux/plugin.cc

@@ -227,6 +227,21 @@ extern "C" struct passwd *getpwuid(uid_t uid)
 }
 
 
+extern "C" int getdtablesize()
+{
+	if (!noux_syscall(Noux::Session::SYSCALL_GETDTABLESIZE)) {
+		PWRN("getdtablesize syscall failed");
+		errno = ENOSYS;
+		return -1;
+	}
+
+	int n = sysio()->getdtablesize_out.n;
+	if (verbose)
+		PDBG("%d", n);
+	return n;
+}
+
+
 extern "C" uid_t getgid()
 {
 	sysio()->userinfo_in.request = Noux::Sysio::USERINFO_GET_GID;

repos/ports/src/noux/main.cc

@@ -864,6 +864,14 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 				break;
 			}
 
+		case SYSCALL_GETDTABLESIZE:
+			{
+				_sysio->getdtablesize_out.n =
+					Noux::File_descriptor_registry::MAX_FILE_DESCRIPTORS;
+				result = true;
+				break;
+			}
+
 		case SYSCALL_SOCKET:
 		case SYSCALL_GETSOCKOPT:
 		case SYSCALL_SETSOCKOPT: