Let tests pass more than one FD

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

fdpass.c

@@ -17,19 +17,26 @@
 
 #include "fdpass.h"
 
+#define MAX_FDS		128
+
+struct fd_pass {
+	struct cmsghdr	cmsghdr;
+	int		fd[MAX_FDS];
+};
+
 ssize_t
-sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
+sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd, int *nfdp)
 {
 	ssize_t		size;
 
+	printf ("sock_fd_read\n");
 	if (fd) {
 		struct msghdr	msg;
 		struct iovec	iov;
-		union {
+		struct fd_pass	pass;
-			struct cmsghdr	cmsghdr;
+		int		nfd_passed, nfd;
-			char		control[CMSG_SPACE(sizeof (int))];
+		int		i;
-		} cmsgu;
+		int		*fd_passed;
-		struct cmsghdr	*cmsg;
 
 		iov.iov_base = buf;
 		iov.iov_len = bufsize;
@@ -38,35 +45,47 @@ sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
 		msg.msg_namelen = 0;
 		msg.msg_iov = &iov;
 		msg.msg_iovlen = 1;
-		msg.msg_control = cmsgu.control;
+		msg.msg_control = &pass;
-		msg.msg_controllen = sizeof(cmsgu.control);
+		msg.msg_controllen = sizeof pass;
 		size = recvmsg (sock, &msg, 0);
 		if (size < 0) {
 			perror ("recvmsg");
 			exit(1);
 		}
-		if ((msg.msg_flags & MSG_TRUNC) ||
+		if (size > 0 && pass.cmsghdr.cmsg_len > sizeof (struct cmsghdr)) {
-		    (msg.msg_flags & MSG_CTRUNC)) {
+			if ((msg.msg_flags & MSG_TRUNC) ||
-			fprintf (stderr, "control message truncated");
+			    (msg.msg_flags & MSG_CTRUNC)) {
-			exit(1);
+				fprintf (stderr, "control message truncated");
-		}
-		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) {
+			if (pass.cmsghdr.cmsg_level != SOL_SOCKET) {
+				fprintf (stderr, "invalid cmsg_level %d\n",
+					 pass.cmsghdr.cmsg_level);
+				exit(1);
+			}
+			if (pass.cmsghdr.cmsg_type != SCM_RIGHTS) {
 				fprintf (stderr, "invalid cmsg_type %d\n",
-					 cmsg->cmsg_type);
+					 pass.cmsghdr.cmsg_type);
 				exit(1);
 			}
 
-			*fd = *((int *) CMSG_DATA(cmsg));
+			nfd_passed = (pass.cmsghdr.cmsg_len - sizeof (struct cmsghdr)) / sizeof (int);
-			printf ("received fd %d\n", *fd);
+			fd_passed = (int *) CMSG_DATA(&pass.cmsghdr);
+
+			nfd = *nfdp;
+			if (nfd > nfd_passed)
+				nfd = nfd_passed;
+
+			memcpy(fd, fd_passed, nfd * sizeof (int));
+			for (i = 0; i < nfd; i++)
+				printf ("received fd %d\n", fd[i]);
+			for (i = nfd; i < nfd_passed; i++) {
+				printf ("dropping fd %d\n", fd_passed[i]);
+				close(fd_passed[i]);
+			}
+			*nfdp = nfd;
 		} else
-			*fd = -1;
+			*nfdp = 0;
 	} else {
 		size = read (sock, buf, bufsize);
 		if (size < 0) {
@@ -78,36 +97,43 @@ 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)
+sock_fd_write(int sock, void *buf, ssize_t buflen, int *fd, int nfd)
 {
 	ssize_t		size;
 	struct msghdr	msg;
 	struct iovec	iov;
-	union {
+	struct fd_pass	pass;
-		struct cmsghdr	cmsghdr;
+	int		i;
-		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;
+	if (buflen) {
-	msg.msg_iovlen = 1;
+		msg.msg_iov = &iov;
+		msg.msg_iovlen = 1;
+	} else {
+		msg.msg_iov = NULL;
+		msg.msg_iovlen = 0;
+	}
 
-	if (fd != -1) {
+	if (nfd) {
-		msg.msg_control = cmsgu.control;
+		if (nfd > MAX_FDS) {
-		msg.msg_controllen = sizeof(cmsgu.control);
+			printf ("passing too many fds\n");
+			exit(1);
+		}
 
-		cmsg = CMSG_FIRSTHDR(&msg);
+		msg.msg_control = &pass;
-		cmsg->cmsg_len = CMSG_LEN(sizeof (int));
+		msg.msg_controllen = sizeof (struct cmsghdr) + nfd * sizeof (int);
-		cmsg->cmsg_level = SOL_SOCKET;
-		cmsg->cmsg_type = SCM_RIGHTS;
 
-		printf ("passing fd %d\n", fd);
+		pass.cmsghdr.cmsg_len = msg.msg_controllen;
-		*((int *) CMSG_DATA(cmsg)) = fd;
+		pass.cmsghdr.cmsg_level = SOL_SOCKET;
+		pass.cmsghdr.cmsg_type = SCM_RIGHTS;
+
+		memcpy(&pass.fd, fd, nfd * sizeof (int));
+		for (i = 0; i < nfd; i++)
+			printf ("passing fd %d\n", pass.fd[i]);
 	} else {
 		msg.msg_control = NULL;
 		msg.msg_controllen = 0;

fdpass.h

@@ -20,16 +20,18 @@
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/stat.h>
 #include <signal.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <fcntl.h>
 
 ssize_t
-sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd);
+sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd, int *nfd);
 
 ssize_t
-sock_fd_write(int sock, void *buf, ssize_t buflen, int fd);
+sock_fd_write(int sock, void *buf, ssize_t buflen, int *fd, int nfd);
 
 #endif

fdpassing.c

@@ -17,22 +17,29 @@
 
 #include "fdpass.h"
 
+#define NFD	128
+
 void
 child(int sock)
 {
-	int	fd;
+	int	fd[NFD];
+	int	nfd;
 	char	buf[16];
 	ssize_t	size;
+	int	i;
 
 	sleep(1);
 	for (;;) {
-		size = sock_fd_read(sock, buf, sizeof(buf), &fd);
+		nfd = NFD;
+		size = sock_fd_read(sock, buf, sizeof(buf), fd, &nfd);
 		if (size <= 0)
 			break;
 		printf ("read %d\n", size);
-		if (fd != -1) {
+		if (nfd) {
-			write(fd, "hello, world\n", 13);
+			for (i = 0; i < nfd; i++) {
-			close(fd);
+				write(fd[i], "hello, world\n", 13);
+				close(fd[i]);
+			}
 		}
 	}
 }
@@ -42,10 +49,11 @@ parent(int sock)
 {
 	ssize_t	size;
 	int	i;
-	int	fd;
+	int	fd[NFD];
 
-	fd = 1;
+	for (i = 0; i < NFD; i++)
-	size = sock_fd_write(sock, "1", 1, 1);
+		fd[i] = 1 + (i & 1);
+	size = sock_fd_write(sock, "1", 1, fd, NFD);
 	printf ("wrote %d\n", size);
 }
 

lostfd.c

@@ -17,25 +17,32 @@
 
 #include "fdpass.h"
 
+#define NFD	16
+
 void
 child(int sock)
 {
-	int	fd;
+	int	fd[NFD];
+	int	nfd;
 	char	buf[16];
 	ssize_t	size;
+	int	i;
 
 	sleep(1);
-	size = sock_fd_read(sock, buf, sizeof(buf), NULL);
+	size = sock_fd_read(sock, buf, sizeof(buf), NULL, NULL);
 	if (size <= 0)
 		return;
 	printf ("read %d\n", size);
-	size = sock_fd_read(sock, buf, sizeof(buf), &fd);
+	nfd = NFD;
+	size = sock_fd_read(sock, buf, sizeof(buf), fd, &nfd);
 	if (size <= 0)
 		return;
 	printf ("read %d\n", size);
-	if (fd != -1) {
+	if (nfd) {
-		write(fd, "hello, world\n", 13);
+		for (i = 0; i < nfd; i++) {
-		close(fd);
+			write(fd[i], "hello, world\n", 13);
+			close(fd[i]);
+		}
 	}
 }
 
@@ -47,9 +54,10 @@ parent(int sock)
 	int	fd;
 
 	fd = 1;
-	size = sock_fd_write(sock, "1", 1, 1);
+	size = sock_fd_write(sock, "1", 1, &fd, 1);
 	printf ("wrote %d without fd\n", size);
-	size = sock_fd_write(sock, "1", 1, 2);
+	fd = 2;
+	size = sock_fd_write(sock, "1", 1, &fd, 1);
 	printf ("wrote %d with fd\n", size);
 }
 

multiwrite.c

@@ -17,22 +17,29 @@
 
 #include "fdpass.h"
 
+#define NFD	32
+
 void
 child(int sock)
 {
-	int	fd;
+	int	fd[NFD];
 	char	buf[16];
 	ssize_t	size;
+	int	nfd;
+	int	i;
 
 	sleep(1);
 	for (;;) {
-		size = sock_fd_read(sock, buf, sizeof(buf), &fd);
+		nfd = NFD;
+		size = sock_fd_read(sock, buf, sizeof(buf), fd, &nfd);
 		if (size <= 0)
 			break;
 		printf ("read %d\n", size);
-		if (fd != -1) {
+		if (nfd) {
-			write(fd, "hello, world\n", 13);
+			for (i = 0; i < nfd; i++) {
-			close(fd);
+				write(fd[i], "hello, world\n", 13);
+				close(fd[i]);
+			}
 		}
 	}
 }
@@ -45,11 +52,11 @@ parent(int sock)
 	int	fd;
 
 	fd = 1;
-	size = sock_fd_write(sock, "1", 1, -1);
+	size = sock_fd_write(sock, "1", 1, NULL, 0);
 	printf ("wrote %d without fd\n", size);
-	size = sock_fd_write(sock, "1", 1, 1);
+	size = sock_fd_write(sock, "1", 1, &fd, 1);
 	printf ("wrote %d with fd\n", size);
-	size = sock_fd_write(sock, "1", 1, -1);
+	size = sock_fd_write(sock, "1", 1, NULL, 0);
 	printf ("wrote %d without fd\n", size);
 }
 

xreq.c

@@ -27,11 +27,13 @@ child(int sock)
 	int	i, reqlen;
 	ssize_t	size, fdsize;
 	int	fd = -1, *fdp;
+	int	nfd;
 	int	j;
 
 	sleep (1);
 	for (j = 0;; j++) {
-		size = sock_fd_read(sock, xreq, sizeof (xreq), NULL);
+		nfd = 0;
+		size = sock_fd_read(sock, xreq, sizeof (xreq), NULL, &nfd);
 		printf ("got %d\n", size);
 		if (size == 0)
 			break;
@@ -48,7 +50,8 @@ child(int sock)
 					fprintf (stderr, "Got fd req, but not at end of input %d < %d\n",
 						 i, size);
 				}
-				fdsize = sock_fd_read(sock, xnop, sizeof (xnop), &fd);
+				nfd = 1;
+				fdsize = sock_fd_read(sock, xnop, sizeof (xnop), &fd, &nfd);
 				if (fd == -1) {
 					fprintf (stderr, "no fd received\n");
 				} else {
@@ -89,19 +92,20 @@ parent(int sock)
 		for (i = 0; i < 8; i++) {
 			xreq[0] = 0;
 			xreq[1] = sizeof (xreq);
-			sock_fd_write(sock, xreq, sizeof (xreq), -1);
+			sock_fd_write(sock, xreq, sizeof (xreq), NULL, 0);
 		}
 
 		/* Write our 'pass an fd' request with a 'useless' FD to block the receiver */
 		xreq[0] = 1;
 		xreq[1] = sizeof(xreq);
-		sock_fd_write(sock, xreq, sizeof (xreq), 1);
+		fd = 1;
+		sock_fd_write(sock, xreq, sizeof (xreq), &fd, 1);
 
 		/* Pass an fd */
 		xnop[0] = 2;
 		xnop[1] = sizeof (xnop);
 		fd = tmp_file(j);
-		sock_fd_write(sock, xnop, sizeof (xnop), fd);
+		sock_fd_write(sock, xnop, sizeof (xnop), &fd, 1);
 		close(fd);
 	}
 }

zerowrite.c

@@ -20,17 +20,18 @@
 void
 child(int sock)
 {
-	int	fd;
+	int	fd, nfd;
 	char	buf[16];
 	ssize_t	size;
 
 	sleep(1);
 	for (;;) {
-		size = sock_fd_read(sock, buf, sizeof(buf), &fd);
+		nfd = 1;
+		size = sock_fd_read(sock, buf, sizeof(buf), &fd, &nfd);
 		if (size <= 0)
 			break;
-		printf ("read %d\n", size);
+		printf ("read %d nfd %d\n", size, nfd);
-		if (fd != -1) {
+		if (nfd == 1) {
 			write(fd, "hello, world\n", 13);
 			close(fd);
 		}
@@ -45,11 +46,11 @@ parent(int sock)
 	int	fd;
 
 	fd = 1;
-	size = sock_fd_write(sock, "1", 1, -1);
+	size = sock_fd_write(sock, "1", 1, NULL, 0);
 	printf ("wrote %d without fd\n", size);
-	size = sock_fd_write(sock, NULL, 0, 1);
+	size = sock_fd_write(sock, NULL, 0, &fd, 1);
 	printf ("wrote %d with fd\n", size);
-	size = sock_fd_write(sock, "1", 1, -1);
+	size = sock_fd_write(sock, "1", 1, NULL, 0);
 	printf ("wrote %d without fd\n", size);
 }