diff --git a/tasks/libposix/lseek.c b/tasks/libposix/lseek.c
index 683c096..7df100f 100644
--- a/tasks/libposix/lseek.c
+++ b/tasks/libposix/lseek.c
@@ -20,15 +20,14 @@ static inline off_t l4_lseek(int fildes, off_t offset, int whence)
 	write_mr(L4SYS_ARG2, whence);
 
 	/* Call pager with shmget() request. Check ipc error. */
-	if ((errno = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_LSEEK)) < 0) {
-		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, errno);
-		return -1;
+	if ((offres = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_LSEEK)) < 0) {
+		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, offres);
+		return offres;
 	}
 	/* Check if syscall itself was successful */
 	if ((offres = l4_get_retval()) < 0) {
 		printf("%s: OPEN Error: %d.\n", __FUNCTION__, (int)offres);
-		errno = (int)offres;
-		return -1;
+		return offres;
 
 	}
 	return offres;
@@ -36,6 +35,15 @@ static inline off_t l4_lseek(int fildes, off_t offset, int whence)
 
 off_t lseek(int fildes, off_t offset, int whence)
 {
-	return l4_lseek(fildes, offset, whence);
+	int ret = l4_lseek(fildes, offset, whence);
+
+	/* If error, return positive error code */
+	if (ret < 0) {
+		errno = -ret;
+		return -1;
+	}
+	/* else return value */
+	return ret;
+
 }
 
diff --git a/tasks/libposix/mmap.c b/tasks/libposix/mmap.c
index 6eb99f5..dd5078d 100644
--- a/tasks/libposix/mmap.c
+++ b/tasks/libposix/mmap.c
@@ -12,6 +12,11 @@
 #include <l4lib/arch/syslib.h>
 #include <l4lib/ipcdefs.h>
 
+/* FIXME: Implement the same separation that is in read.c write.c etc. such that
+ * l4_syscall returns negative value and then the actual posix glue sets the errno
+ * rather than the l4_syscall sets it itself
+ */
+
 struct mmap_descriptor {
 	void *start;
 	size_t length;
diff --git a/tasks/libposix/open.c b/tasks/libposix/open.c
index a53569f..cb57247 100644
--- a/tasks/libposix/open.c
+++ b/tasks/libposix/open.c
@@ -23,22 +23,21 @@ static inline int l4_open(const char *pathname, int flags, mode_t mode)
 	write_mr(L4SYS_ARG2, (u32)mode);
 
 	/* Call pager with shmget() request. Check ipc error. */
-	if ((errno = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_OPEN)) < 0) {
-		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, errno);
-		return -1;
+	if ((fd = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_OPEN)) < 0) {
+		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, fd);
+		return fd;
 	}
 	/* Check if syscall itself was successful */
 	if ((fd = l4_get_retval()) < 0) {
 		printf("%s: OPEN Error: %d.\n", __FUNCTION__, fd);
-		errno = fd;
-		return -1;
-
+		return fd;
 	}
 	return fd;
 }
 
 int open(const char *pathname, int oflag, ...)
 {
+	int ret;
 	mode_t mode = 0;
 
 	if (oflag & O_CREAT) {
@@ -47,6 +46,15 @@ int open(const char *pathname, int oflag, ...)
 		mode = va_arg(arg, mode_t);
 		va_end(arg);
 	}
-	return l4_open(pathname, oflag, mode);
+	ret = l4_open(pathname, oflag, mode);
+
+	/* If error, return positive error code */
+	if (ret < 0) {
+		errno = -ret;
+		return -1;
+	}
+	/* else return value */
+	return ret;
+
 }
 
diff --git a/tasks/libposix/write.c b/tasks/libposix/write.c
index a0d25af..b64b31c 100644
--- a/tasks/libposix/write.c
+++ b/tasks/libposix/write.c
@@ -20,15 +20,14 @@ static inline int l4_write(int fd, const void *buf, size_t count)
 	write_mr(L4SYS_ARG2, count);
 
 	/* Call pager with shmget() request. Check ipc error. */
-	if ((errno = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_WRITE)) < 0) {
-		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, errno);
-		return -1;
+	if ((wrcnt = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_WRITE)) < 0) {
+		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, wrcnt);
+		return wrcnt;
 	}
 	/* Check if syscall itself was successful */
 	if ((wrcnt = l4_get_retval()) < 0) {
 		printf("%s: WRITE Error: %d.\n", __FUNCTION__, (int)wrcnt);
-		errno = (int)wrcnt;
-		return -1;
+		return wrcnt;
 
 	}
 	return wrcnt;
@@ -36,9 +35,19 @@ static inline int l4_write(int fd, const void *buf, size_t count)
 
 ssize_t write(int fd, const void *buf, size_t count)
 {
+	int ret;
+
 	if (!count)
 		return 0;
 
-	return l4_write(fd, buf, count);
+	ret = l4_write(fd, buf, count);
+
+	/* If error, return positive error code */
+	if (ret < 0) {
+		errno = -ret;
+		return -1;
+	}
+	/* else return value */
+	return ret;
 }