diff --git a/headers/posix/unistd.h b/headers/posix/unistd.h
index ea43538c92..15333ea6db 100644
--- a/headers/posix/unistd.h
+++ b/headers/posix/unistd.h
@@ -39,6 +39,7 @@
 #define _POSIX_THREADS			(200112L)
 
 /* pathconf() constants */
+/* BeOS supported values, do not touch */
 #define _PC_CHOWN_RESTRICTED	1
 #define _PC_MAX_CANON			2
 #define _PC_MAX_INPUT			3
@@ -48,8 +49,25 @@
 #define _PC_PIPE_BUF			7
 #define _PC_VDISABLE			8
 #define _PC_LINK_MAX			25
+/* new values */
+/* TODO: reorder */
+#define _PC_SYNC_IO				26
+#define _PC_ASYNC_IO			27
+#define _PC_PRIO_IO				28
+#define _PC_SOCK_MAXBUF			29
+#define _PC_FILESIZEBITS		30
+#define _PC_REC_INCR_XFER_SIZE	31
+#define _PC_REC_MAX_XFER_SIZE	32
+#define _PC_REC_MIN_XFER_SIZE	33
+#define _PC_REC_XFER_ALIGN		34
+#define _PC_ALLOC_SIZE_MIN		35
+#define _PC_SYMLINK_MAX			36
+#define _PC_2_SYMLINKS			37
+#define _PC_XATTR_EXISTS		38
+#define _PC_XATTR_ENABLED		39
 
 /* sysconf() constants */
+/* BeOS supported values, do not touch */
 #define _SC_ARG_MAX				15
 #define _SC_CHILD_MAX			16
 #define _SC_CLK_TCK				17
diff --git a/src/system/libroot/posix/unistd/conf.c b/src/system/libroot/posix/unistd/conf.c
index fccf5dd6c7..fc9a05640e 100644
--- a/src/system/libroot/posix/unistd/conf.c
+++ b/src/system/libroot/posix/unistd/conf.c
@@ -80,6 +80,11 @@ sysconf(int name)
 long
 fpathconf(int fd, int name)
 {
+	if (fd < 0) {
+		errno = EBADF;
+		return -1;
+	}
+
 	// TODO: should query the underlying filesystem
 	// for correct value, as most are fs-dependant
 	// (which is why it's a different call than sysconf() btw).
@@ -111,6 +116,32 @@ fpathconf(int fd, int name)
 		case _PC_VDISABLE:
 			return _POSIX_VDISABLE;
 
+		case _PC_FILESIZEBITS:
+			return 64;
+
+		case _PC_XATTR_EXISTS:
+		case _PC_XATTR_ENABLED:
+			/* those seem to be Solaris specific,
+			 * else we should return 1 I suppose.
+			 */
+			errno = EINVAL;
+			return -1;
+
+		case _PC_SYNC_IO:
+		case _PC_ASYNC_IO:
+		case _PC_PRIO_IO:
+		case _PC_SOCK_MAXBUF:
+		case _PC_REC_INCR_XFER_SIZE:
+		case _PC_REC_MAX_XFER_SIZE:
+		case _PC_REC_MIN_XFER_SIZE:
+		case _PC_REC_XFER_ALIGN:
+		case _PC_ALLOC_SIZE_MIN:
+		case _PC_SYMLINK_MAX:
+		case _PC_2_SYMLINKS:
+			/* not yet supported */
+			errno = EINVAL;
+			return -1;
+
 	}
 
 	errno = EINVAL;