diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index c1f0f76291cf3c8ab5a159582bd942d97e2c2ff8..5d258eb4f50645f237b4dd1e0ec880bd1145e26f 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -132,10 +132,10 @@ static int aio_thread(void *arg)
 				{ .data = (void *) (long) event.data,
 						.err	= event.res });
 			reply_fd = ((struct aio_context *) reply.data)->reply_fd;
-			err = os_write_file(reply_fd, &reply, sizeof(reply));
+			err = write(reply_fd, &reply, sizeof(reply));
 			if(err != sizeof(reply))
 				printk("aio_thread - write failed, fd = %d, "
-				       "err = %d\n", reply_fd, -err);
+				       "err = %d\n", reply_fd, errno);
 		}
 	}
 	return 0;
@@ -147,7 +147,7 @@ static int do_not_aio(struct aio_thread_req *req)
 {
 	char c;
 	unsigned long long actual;
-	int err;
+	int n;
 
 	actual = lseek64(req->io_fd, req->offset, SEEK_SET);
 	if(actual != req->offset)
@@ -155,21 +155,22 @@ static int do_not_aio(struct aio_thread_req *req)
 
 	switch(req->type){
 	case AIO_READ:
-		err = os_read_file(req->io_fd, req->buf, req->len);
+		n = read(req->io_fd, req->buf, req->len);
 		break;
 	case AIO_WRITE:
-		err = os_write_file(req->io_fd, req->buf, req->len);
+		n = write(req->io_fd, req->buf, req->len);
 		break;
 	case AIO_MMAP:
-		err = os_read_file(req->io_fd, &c, sizeof(c));
+		n = read(req->io_fd, &c, sizeof(c));
 		break;
 	default:
 		printk("do_not_aio - bad request type : %d\n", req->type);
-		err = -EINVAL;
-		break;
+		return -EINVAL;
 	}
 
-	return err;
+	if(n < 0)
+		return -errno;
+	return 0;
 }
 
 /* These are initialized in initcalls and not changed */
@@ -185,12 +186,12 @@ static int not_aio_thread(void *arg)
 
 	signal(SIGWINCH, SIG_IGN);
 	while(1){
-		err = os_read_file(aio_req_fd_r, &req, sizeof(req));
+		err = read(aio_req_fd_r, &req, sizeof(req));
 		if(err != sizeof(req)){
 			if(err < 0)
 				printk("not_aio_thread - read failed, "
 				       "fd = %d, err = %d\n", aio_req_fd_r,
-				       -err);
+				       errno);
 			else {
 				printk("not_aio_thread - short read, fd = %d, "
 				       "length = %d\n", aio_req_fd_r, err);
@@ -200,10 +201,10 @@ static int not_aio_thread(void *arg)
 		err = do_not_aio(&req);
 		reply = ((struct aio_thread_reply) { .data 	= req.aio,
 						     .err	= err });
-		err = os_write_file(req.aio->reply_fd, &reply, sizeof(reply));
+		err = write(req.aio->reply_fd, &reply, sizeof(reply));
 		if(err != sizeof(reply))
 			printk("not_aio_thread - write failed, fd = %d, "
-			       "err = %d\n", req.aio->reply_fd, -err);
+			       "err = %d\n", req.aio->reply_fd, errno);
 	}
 
 	return 0;
@@ -277,10 +278,12 @@ static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len,
 	if(err){
 		reply = ((struct aio_thread_reply) { .data = aio,
 					 .err  = err });
-		err = os_write_file(aio->reply_fd, &reply, sizeof(reply));
-		if(err != sizeof(reply))
+		err = write(aio->reply_fd, &reply, sizeof(reply));
+		if(err != sizeof(reply)){
+			err = -errno;
 			printk("submit_aio_26 - write failed, "
 			       "fd = %d, err = %d\n", aio->reply_fd, -err);
+		}
 		else err = 0;
 	}
 
@@ -375,9 +378,10 @@ static int submit_aio_24(enum aio_type type, int io_fd, char *buf, int len,
 	};
 	int err;
 
-	err = os_write_file(aio_req_fd_w, &req, sizeof(req));
+	err = write(aio_req_fd_w, &req, sizeof(req));
 	if(err == sizeof(req))
 		err = 0;
+	else err = -errno;
 
 	return err;
 }
diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index fd6cfa5b4a78226e76c7c5b2b220439542175933..acba301612879b4af1d45b96f9b416f8e35a98f6 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -48,9 +48,9 @@ static void etap_change(int op, unsigned char *addr, unsigned char *netmask,
 	change.what = op;
 	memcpy(change.addr, addr, sizeof(change.addr));
 	memcpy(change.netmask, netmask, sizeof(change.netmask));
-	n = os_write_file(fd, &change, sizeof(change));
+	CATCH_EINTR(n = write(fd, &change, sizeof(change)));
 	if(n != sizeof(change)){
-		printk("etap_change - request failed, err = %d\n", -n);
+		printk("etap_change - request failed, err = %d\n", errno);
 		return;
 	}
 
@@ -123,10 +123,11 @@ static int etap_tramp(char *dev, char *gate, int control_me,
 		err = pid;
 	os_close_file(data_remote);
 	os_close_file(control_remote);
-	n = os_read_file(control_me, &c, sizeof(c));
+	CATCH_EINTR(n = read(control_me, &c, sizeof(c)));
 	if(n != sizeof(c)){
-		printk("etap_tramp : read of status failed, err = %d\n", -n);
-		return -EINVAL;
+		err = -errno;
+		printk("etap_tramp : read of status failed, err = %d\n", -err);
+		return err;
 	}
 	if(c != 1){
 		printk("etap_tramp : uml_net failed\n");
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 8a4c9e47326c62d9bb72f97574b2a21c36570ae5..97bed16bf4c73c2817ceffa283589a8aa02753ef 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -36,7 +36,7 @@ static int helper_child(void *arg)
 	errval = execvp_noalloc(data->buf, argv[0], argv);
 	printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0],
 	       -errval);
-	os_write_file(data->fd, &errval, sizeof(errval));
+	write(data->fd, &errval, sizeof(errval));
 	kill(os_getpid(), SIGKILL);
 	return 0;
 }
@@ -92,11 +92,12 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
 	 * Read the errno value from the child, if the exec failed, or get 0 if
 	 * the exec succeeded because the pipe fd was set as close-on-exec.
 	 */
-	n = os_read_file(fds[0], &ret, sizeof(ret));
+	n = read(fds[0], &ret, sizeof(ret));
 	if (n == 0) {
 		ret = pid;
 	} else {
 		if (n < 0) {
+			n = -errno;
 			printk("run_helper : read on pipe failed, ret = %d\n",
 			       -n);
 			ret = n;
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index 77d16023c286cfcb7dbc1e88e72d2705586ac180..c6378c6d10d2821f2d4da93a7618d5ce1935302d 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -232,10 +232,9 @@ int __init create_tmp_file(unsigned long long len)
 
 	zero = 0;
 
-	err = os_write_file(fd, &zero, 1);
+	err = write(fd, &zero, 1);
 	if(err != 1){
-		errno = -err;
-		perror("os_write_file");
+		perror("write");
 		exit(1);
 	}
 
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index a84a45843f83a04de1b61fd3cfce096e2ecf33d1..92a7b59120d616692021376bea33ff5226053b04 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -42,10 +42,10 @@ unsigned long os_process_pc(int pid)
 		       proc_stat, -fd);
 		return ARBITRARY_ADDR;
 	}
-	err = os_read_file(fd, buf, sizeof(buf));
+	CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
 	if(err < 0){
 		printk("os_process_pc - couldn't read '%s', err = %d\n",
-		       proc_stat, -err);
+		       proc_stat, errno);
 		os_close_file(fd);
 		return ARBITRARY_ADDR;
 	}
@@ -75,11 +75,11 @@ int os_process_parent(int pid)
 		return FAILURE_PID;
 	}
 
-	n = os_read_file(fd, data, sizeof(data));
+	CATCH_EINTR(n = read(fd, data, sizeof(data)));
 	os_close_file(fd);
 
 	if(n < 0){
-		printk("Couldn't read '%s', err = %d\n", stat, -n);
+		printk("Couldn't read '%s', err = %d\n", stat, errno);
 		return FAILURE_PID;
 	}
 
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 8ccf6a36f1c62b9faba9c5f3e0ec83c8adf8c47c..8d4e0c6b8c92e085e697557f68e59b87af7afe23 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -69,11 +69,12 @@ static int write_sigio_thread(void *unused)
 			p = &fds->poll[i];
 			if(p->revents == 0) continue;
 			if(p->fd == sigio_private[1]){
-				n = os_read_file(sigio_private[1], &c, sizeof(c));
+				CATCH_EINTR(n = read(sigio_private[1], &c,
+						     sizeof(c)));
 				if(n != sizeof(c))
 					printk("write_sigio_thread : "
 					       "read on socket failed, "
-					       "err = %d\n", -n);
+					       "err = %d\n", errno);
 				tmp = current_poll;
 				current_poll = next_poll;
 				next_poll = tmp;
@@ -86,10 +87,10 @@ static int write_sigio_thread(void *unused)
 					(fds->used - i) * sizeof(*fds->poll));
 			}
 
-			n = os_write_file(respond_fd, &c, sizeof(c));
+			CATCH_EINTR(n = write(respond_fd, &c, sizeof(c)));
 			if(n != sizeof(c))
 				printk("write_sigio_thread : write on socket "
-				       "failed, err = %d\n", -n);
+				       "failed, err = %d\n", errno);
 		}
 	}
 
@@ -127,15 +128,15 @@ static void update_thread(void)
 	char c;
 
 	flags = set_signals(0);
-	n = os_write_file(sigio_private[0], &c, sizeof(c));
+	n = write(sigio_private[0], &c, sizeof(c));
 	if(n != sizeof(c)){
-		printk("update_thread : write failed, err = %d\n", -n);
+		printk("update_thread : write failed, err = %d\n", errno);
 		goto fail;
 	}
 
-	n = os_read_file(sigio_private[0], &c, sizeof(c));
+	CATCH_EINTR(n = read(sigio_private[0], &c, sizeof(c)));
 	if(n != sizeof(c)){
-		printk("update_thread : read failed, err = %d\n", -n);
+		printk("update_thread : read failed, err = %d\n", errno);
 		goto fail;
 	}
 
@@ -459,10 +460,10 @@ static void tty_output(int master, int slave)
 
 	memset(buf, 0, sizeof(buf));
 
-	while(os_write_file(master, buf, sizeof(buf)) > 0) ;
+	while(write(master, buf, sizeof(buf)) > 0) ;
 	if(errno != EAGAIN)
 		panic("tty_output : write failed, errno = %d\n", errno);
-	while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
+	while(((n = read(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
 
 	if(got_sigio){
 		printk("Yes\n");
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 470ec531aa5dda4cd92a4baed2b2aa2952f00427..6cdfda807b658cf66b1b05a122333a106ab93224 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -6,6 +6,7 @@
 #include <signal.h>
 #include <errno.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
 #include <asm/page.h>
@@ -199,9 +200,11 @@ int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
 					   .fd	= phys_fd,
 					   .offset= offset
 					 } } } );
-		ret = os_write_file(fd, &map, sizeof(map));
-		if(ret != sizeof(map))
+		CATCH_EINTR(ret = write(fd, &map, sizeof(map)));
+		if(ret != sizeof(map)){
+			ret = -errno;
 			printk("map : /proc/mm map failed, err = %d\n", -ret);
+		}
 		else ret = 0;
 	}
 	else {
@@ -231,9 +234,11 @@ int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
 					   { .addr	=
 					     (unsigned long) addr,
 					     .len		= len } } } );
-		ret = os_write_file(fd, &unmap, sizeof(unmap));
-		if(ret != sizeof(unmap))
+		CATCH_EINTR(ret = write(fd, &unmap, sizeof(unmap)));
+		if(ret != sizeof(unmap)){
+			ret = -errno;
 			printk("unmap - proc_mm write returned %d\n", ret);
+		}
 		else ret = 0;
 	}
 	else {
@@ -266,9 +271,11 @@ int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
 					       .len	= len,
 					       .prot	= prot } } } );
 
-		ret = os_write_file(fd, &protect, sizeof(protect));
-		if(ret != sizeof(protect))
+		CATCH_EINTR(ret = write(fd, &protect, sizeof(protect)));
+		if(ret != sizeof(protect)){
+			ret = -errno;
 			printk("protect failed, err = %d", -ret);
+		}
 		else ret = 0;
 	}
 	else {
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 47852698d5e1920b7776488472979be7924bfb85..5b1943dc15e9930204ad9f441b077b40364b279f 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -431,12 +431,13 @@ void map_stub_pages(int fd, unsigned long code,
 					  .fd      = code_fd,
 					  .offset  = code_offset
 	} } });
-	n = os_write_file(fd, &mmop, sizeof(mmop));
+	CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
 	if(n != sizeof(mmop)){
+		n = errno;
 		printk("mmap args - addr = 0x%lx, fd = %d, offset = %llx\n",
 		       code, code_fd, (unsigned long long) code_offset);
 		panic("map_stub_pages : /proc/mm map for code failed, "
-		      "err = %d\n", -n);
+		      "err = %d\n", n);
 	}
 
 	if ( stack ) {
@@ -453,10 +454,10 @@ void map_stub_pages(int fd, unsigned long code,
 				      .fd      = map_fd,
 				      .offset  = map_offset
 		} } });
-		n = os_write_file(fd, &mmop, sizeof(mmop));
+		CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
 		if(n != sizeof(mmop))
 			panic("map_stub_pages : /proc/mm map for data failed, "
-			      "err = %d\n", -n);
+			      "err = %d\n", errno);
 	}
 }
 
diff --git a/arch/um/os-Linux/tty_log.c b/arch/um/os-Linux/tty_log.c
index ae9adb1b74f28fa6054178a5ee3f690f83254cf3..d11a55baa6bd59800860bd0acc822adf89b7ef6b 100644
--- a/arch/um/os-Linux/tty_log.c
+++ b/arch/um/os-Linux/tty_log.c
@@ -53,8 +53,8 @@ int open_tty_log(void *tty, void *current_tty)
 					       .direction = 0,
 					       .sec = tv.tv_sec,
 					       .usec = tv.tv_usec } );
-		os_write_file(tty_log_fd, &data, sizeof(data));
-		os_write_file(tty_log_fd, &current_tty, data.len);
+		write(tty_log_fd, &data, sizeof(data));
+		write(tty_log_fd, &current_tty, data.len);
 		return tty_log_fd;
 	}
 
@@ -83,7 +83,7 @@ void close_tty_log(int fd, void *tty)
 					       .direction = 0,
 					       .sec = tv.tv_sec,
 					       .usec = tv.tv_usec } );
-		os_write_file(tty_log_fd, &data, sizeof(data));
+		write(tty_log_fd, &data, sizeof(data));
 		return;
 	}
 	os_close_file(fd);
@@ -98,10 +98,10 @@ static int log_chunk(int fd, const char *buf, int len)
 		try = (len > sizeof(chunk)) ? sizeof(chunk) : len;
 		missed = copy_from_user_proc(chunk, (char *) buf, try);
 		try -= missed;
-		n = os_write_file(fd, chunk, try);
+		n = write(fd, chunk, try);
 		if(n != try) {
 			if(n < 0)
-				return n;
+				return -errno;
 			return -EIO;
 		}
 		if(missed != 0)
@@ -130,7 +130,7 @@ int write_tty_log(int fd, const char *buf, int len, void *tty, int is_read)
 					       .direction = direction,
 					       .sec = tv.tv_sec,
 					       .usec = tv.tv_usec } );
-		os_write_file(tty_log_fd, &data, sizeof(data));
+		write(tty_log_fd, &data, sizeof(data));
 	}
 
 	return log_chunk(fd, buf, len);
@@ -161,7 +161,7 @@ void log_exec(char **argv, void *tty)
 				       .direction = 0,
 				       .sec = tv.tv_sec,
 				       .usec = tv.tv_usec } );
-	os_write_file(tty_log_fd, &data, sizeof(data));
+	write(tty_log_fd, &data, sizeof(data));
 
 	for(ptr = argv; ; ptr++){
 		if(copy_from_user_proc(&arg, ptr, sizeof(arg)))