Split out I/O functions to separate file

Signed-off-by: Keith Packard <keithp@keithp.com>

Makefile

@@ -1,4 +1,6 @@
 CFLAGS=-O0 -g
 
-fdpassing: fdpassing.o
+all: fdpassing
-	$(CC) -o $@ fdpassing.o
+
+fdpassing: fdpassing.o fdpass.o
+	$(CC) -o $@ fdpassing.o fdpass.o

fdpass.c

@@ -0,0 +1,116 @@
+/*
+ * Copyright © 2012 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "fdpass.h"
+
+int
+sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
+{
+	ssize_t		size;
+	struct msghdr	msg;
+	struct iovec	iov;
+	union {
+		struct cmsghdr	cmsghdr;
+		char		control[CMSG_SPACE(sizeof (int))];
+	} cmsgu;
+	struct cmsghdr	*cmsg;
+
+	iov.iov_base = buf;
+	iov.iov_len = bufsize;
+
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	if (fd) {
+		msg.msg_control = cmsgu.control;
+		msg.msg_controllen = sizeof(cmsgu.control);
+		size = recvmsg (sock, &msg, 0);
+	} else {
+		size = read (sock, buf, bufsize);
+	}
+
+	if (size < 0) {
+		perror("recvmsg");
+		exit(1);
+	}
+
+	
+	if (fd && (cmsg = CMSG_FIRSTHDR(&msg)) &&
+	    cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
+		if (cmsg->cmsg_level != SOL_SOCKET) {
+			fprintf (stderr, "invalid cmsg_level %d\n",
+				 cmsg->cmsg_level);
+			exit(1);
+		}
+		if (cmsg->cmsg_type != SCM_RIGHTS) {
+			fprintf (stderr, "invalid cmsg_type %d\n",
+				 cmsg->cmsg_type);
+			exit(1);
+		}
+
+		*fd = *((int *) CMSG_DATA(cmsg));
+		printf ("received fd %d\n", *fd);
+	} else if (fd) {
+		*fd = -1;
+	}
+	return size;
+}
+
+ssize_t
+sock_fd_write(int sock, void *buf, ssize_t buflen, int fd)
+{
+	ssize_t		size;
+	struct msghdr	msg;
+	struct iovec	iov;
+	union {
+		struct cmsghdr	cmsghdr;
+		char		control[CMSG_SPACE(sizeof (int))];
+	} cmsgu;
+	struct cmsghdr	*cmsg;
+
+	iov.iov_base = buf;
+	iov.iov_len = buflen;
+
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	if (fd != -1) {
+		msg.msg_control = cmsgu.control;
+		msg.msg_controllen = sizeof(cmsgu.control);
+
+		cmsg = CMSG_FIRSTHDR(&msg);
+		cmsg->cmsg_len = CMSG_LEN(sizeof (int));
+		cmsg->cmsg_level = SOL_SOCKET;
+		cmsg->cmsg_type = SCM_RIGHTS;
+
+		printf ("passing fd %d\n", fd);
+		*((int *) CMSG_DATA(cmsg)) = fd;
+	} else {
+		msg.msg_control = NULL;
+		msg.msg_controllen = 0;
+		printf ("not passing fd\n");
+	}
+
+	size = sendmsg(sock, &msg, 0);
+
+	if (size < 0)
+		perror ("sendmsg");
+	return size;
+}

fdpass.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright © 2012 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef _FDPASS_H_
+#define _FDPASS_H_
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+int
+sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd);
+
+ssize_t
+sock_fd_write(int sock, void *buf, ssize_t buflen, int fd);
+
+#endif

fdpassing.c

@@ -15,129 +15,73 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  */
 
-#include <sys/types.h>
+#include "fdpass.h"
-#include <sys/socket.h>
-#include <signal.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdio.h>
 
-int
+char *
-sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
+itoa(int i, char *buf)
 {
-	ssize_t		size;
+	buf += 10;
-	struct msghdr	msg;
+	*--buf = '\0';
-	struct iovec	iov;
+	do {
-	union {
+		*--buf = '0' + i % 10;
-		struct cmsghdr	cmsghdr;
+	} while ((i /= 10));
-		char		control[CMSG_SPACE(sizeof (int))];
+	return buf;
-	} cmsgu;
+}
-	struct cmsghdr	*cmsg;
 
-	iov.iov_base = buf;
+void
-	iov.iov_len = bufsize;
+handler(int i)
-
+{
-	msg.msg_name = NULL;
+	char	buf[12];
-	msg.msg_namelen = 0;
+	char	*b = itoa(i, buf);
-	msg.msg_iov = &iov;
+	
-	msg.msg_iovlen = 1;
+	write (2, "signal ", 7);
-	msg.msg_control = cmsgu.control;
+	write (2, b, strlen(b));
-	msg.msg_controllen = sizeof(cmsgu.control);
+	write (2, "\n", 1);
-
+	_exit(1);
-	size = recvmsg (sock, &msg, 0);
-	if (size < 0) {
-		perror("recvmsg");
-		exit(1);
-	}
-
-	cmsg = CMSG_FIRSTHDR(&msg);
-	if (cmsg &&
-	    cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
-		if (cmsg->cmsg_level != SOL_SOCKET) {
-			fprintf (stderr, "invalid cmsg_level %d\n",
-				 cmsg->cmsg_level);
-			exit(1);
-		}
-		if (cmsg->cmsg_type != SCM_RIGHTS) {
-			fprintf (stderr, "invalid cmsg_type %d\n",
-				 cmsg->cmsg_type);
-			exit(1);
-		}
-
-		*fd = *((int *) CMSG_DATA(cmsg));
-		printf ("received fd %d\n", *fd);
-	} else {
-		*fd = -1;
-	}
-	return size;
 }
 
 void
 child(int sock)
 {
-	int	fd;
+	int	fd, *fdp;
 	char	buf[16];
 	ssize_t	size;
+	int	i = 0;
 
-	size = sock_fd_read(sock, buf, sizeof(buf), &fd);
+	signal(SIGSEGV, handler);
-	if (size == 0)
+	sleep(1);
-		return;
+	for (;;) {
-	printf ("read %d\n", size);
+		if (!(i & 1))
-	if (fd != -1)
+			fdp = NULL;
-		write(fd, "hello, world\n", 13);
+		else
-}
+			fdp = &fd;
-
+		size = sock_fd_read(sock, buf, sizeof(buf), fdp);
-ssize_t
+		if (size == 0)
-sock_fd_write(int sock, void *buf, ssize_t buflen, int fd)
+			break;
-{
+		printf ("read %d\n", size);
-	ssize_t		size;
+		if (fdp && fd != -1)
-	struct msghdr	msg;
+			write(fd, "hello, world\n", 13);
-	struct iovec	iov;
+		i++;
-	union {
-		struct cmsghdr	cmsghdr;
-		char		control[CMSG_SPACE(sizeof (int))];
-	} cmsgu;
-	struct cmsghdr	*cmsg;
-
-	iov.iov_base = buf;
-	iov.iov_len = buflen;
-
-	msg.msg_name = NULL;
-	msg.msg_namelen = 0;
-	msg.msg_iov = &iov;
-	msg.msg_iovlen = 1;
-
-	if (fd != -1) {
-		msg.msg_control = cmsgu.control;
-		msg.msg_controllen = sizeof(cmsgu.control);
-
-		cmsg = CMSG_FIRSTHDR(&msg);
-		cmsg->cmsg_len = CMSG_LEN(sizeof (int));
-		cmsg->cmsg_level = SOL_SOCKET;
-		cmsg->cmsg_type = SCM_RIGHTS;
-
-		printf ("passing fd %d\n", fd);
-		*((int *) CMSG_DATA(cmsg)) = fd;
-	} else {
-		msg.msg_control = NULL;
-		msg.msg_controllen = 0;
-		printf ("not passing fd\n");
 	}
-
+	printf ("child done\n");
-	size = sendmsg(sock, &msg, 0);
-
-	if (size < 0)
-		perror ("sendmsg");
-	return size;
 }
 
 void
 parent(int sock)
 {
 	ssize_t	size;
-	size = sock_fd_write(sock, "1", 1, 1);
+	int	i;
+	int	fd;
 
-	printf ("wrote %d\n", size);
+	for (i = 0; i < 8; i++) {
+		if ((i & 1))
+			fd = -1;
+		else
+			fd = 1;
+		size = sock_fd_write(sock, "1", 1, fd);
+		printf ("wrote %d\n", size);
+	}
+	close(sock);
 }
 
 int
@@ -152,15 +96,16 @@ main(int argc, char **argv)
 	}
 	switch ((pid = fork())) {
 	case 0:
+		close(sv[0]);
 		child(sv[1]);
 		break;
 	case -1:
 		perror("fork");
 		exit(1);
 	default:
+		close(sv[1]);
 		parent(sv[0]);
-		sleep(1);
-		kill(pid, SIGTERM);
 		break;
 	}
+	return 0;
 }