Add support for non-blocking I/O. Also fixes problems the providers

and popen() caused with concurrent access.

This should match the original portalfs in functionality now.

usr.sbin/puffs/mount_portal/puffs_portal.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: puffs_portal.c,v 1.1 2007/07/02 18:35:14 pooka Exp $	*/
+/*	$NetBSD: puffs_portal.c,v 1.2 2007/07/08 10:43:03 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007  Antti Kantee.  All Rights Reserved.
@@ -27,6 +27,7 @@
  */
 
 #include <sys/types.h>
+#include <sys/wait.h>
 
 #include <assert.h>
 #include <err.h>
@@ -51,9 +52,10 @@ static void usage(void);
 PUFFSOP_PROTOS(portal);
 
 #define PORTAL_ROOT NULL
+#define METADATASIZE (sizeof(int) + sizeof(size_t))
 
 qelem q;
-int readcfg;
+int readcfg, sigchild;
 const char *cfg;
 
 static void
@@ -71,6 +73,13 @@ sighup(int sig)
 	readcfg = 1;
 }
 
+static void
+sigcry(int sig)
+{
+
+	sigchild = 1;
+}
+
 static void
 portal_loopfn(struct puffs_usermount *pu)
 {
@@ -78,6 +87,273 @@ portal_loopfn(struct puffs_usermount *pu)
 	if (readcfg)
 		conf_read(&q, cfg);
 	readcfg = 0;
+
+	if (sigchild) {
+		sigchild = 0;
+		while (waitpid(-1, NULL, WNOHANG) != -1)
+			continue;
+	}
+}
+
+#define PUFBUF_FD	1
+#define PUFBUF_DATA	2
+
+#define CMSIZE (sizeof(struct cmsghdr) + sizeof(int))
+
+/* receive file descriptor produced by our child process */
+static int
+readfd(struct puffs_framebuf *pufbuf, int fd, int *done)
+{
+	struct cmsghdr *cmp;
+	struct msghdr msg;
+	struct iovec iov;
+	ssize_t n;
+	int error, rv;
+
+	rv = 0;
+	cmp = emalloc(CMSG_LEN(sizeof(int)));
+
+	iov.iov_base = &error;
+	iov.iov_len = sizeof(int);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_control = cmp;
+	msg.msg_controllen = CMSG_LEN(sizeof(int));
+
+	n = recvmsg(fd, &msg, 0);
+	if (n == -1) {
+		rv = errno;
+		goto out;
+	}
+	if (n == 0) {
+		rv = ECONNRESET;
+		goto out;
+	}
+
+	/* the data for the server */
+	puffs_framebuf_putdata_atoff(pufbuf, 0, &error, sizeof(int));
+	puffs_framebuf_putdata_atoff(pufbuf, sizeof(int),
+	    CMSG_DATA(cmp), sizeof(int));
+	*done = 1;
+
+ out:
+	free(cmp);
+	return rv;
+}
+
+/* receive data from provider */
+static int
+readdata(struct puffs_framebuf *pufbuf, int fd, int *done)
+{
+	char buf[1024];
+	size_t max;
+	ssize_t n;
+	int moved = 0;
+
+	/* we're always done */
+	*done = 1;
+
+	/* don't override metadata */
+	if (puffs_framebuf_telloff(pufbuf) == 0)
+		puffs_framebuf_seekset(pufbuf, METADATASIZE);
+	puffs_framebuf_getdata_atoff(pufbuf, sizeof(int), &max, sizeof(size_t));
+
+	do {
+		n = read(fd, buf, MIN(sizeof(buf), max));
+		if (n == 0) {
+			if (moved)
+				return 0;
+			else
+				return -1; /* caught by read */
+		}
+		if (n < 0) {
+			if (errno != EAGAIN)
+				return errno;
+			break;
+		}
+
+		puffs_framebuf_putdata(pufbuf, buf, n);
+		moved = 1;
+		max -= n;
+	} while (n == sizeof(buf) || max == 0);
+
+	return 0;
+}
+
+static int
+portal_frame_rf(struct puffs_usermount *pu, struct puffs_framebuf *pufbuf,
+	int fd, int *done)
+{
+	int type;
+
+	if (puffs_framebuf_getdata_atoff(pufbuf, 0, &type, sizeof(int)) == -1)
+		return EINVAL;
+
+	if (type == PUFBUF_FD)
+		return readfd(pufbuf, fd, done);
+	else if (type == PUFBUF_DATA)
+		return readdata(pufbuf, fd, done);
+	else
+		abort();
+}
+
+static int
+portal_frame_wf(struct puffs_usermount *pu, struct puffs_framebuf *pufbuf,
+	int fd, int *done)
+{
+	void *win;
+	size_t pbsize, pboff, winlen;
+	ssize_t n;
+	int moved, error;
+
+	pboff = puffs_framebuf_telloff(pufbuf);
+	pbsize = puffs_framebuf_tellsize(pufbuf);
+	error = 0;
+
+	do {
+		assert(pbsize > pboff);
+		winlen = pbsize - pboff;
+		if (puffs_framebuf_getwindow(pufbuf, pboff, &win, &winlen)==-1)
+			return errno;
+		n = write(fd, win, winlen);
+		if (n == 0) {
+			if (moved)
+				return 0;
+			else {
+				error = -1; /* caught by node_write */
+				break;
+			}
+		}
+		if (n < 0) {
+			if (errno != EAGAIN) {
+				error = errno;
+				break;
+			}
+			return 0;
+		}
+
+		pboff += n;
+		puffs_framebuf_seekset(pufbuf, pboff);
+		moved = 1;
+	} while (pboff != pbsize);
+
+	*done = 1;
+	puffs_framebuf_putdata_atoff(pufbuf, 0, &pboff, sizeof(size_t));
+	return error;
+}
+
+static void
+portal_frame_notify(struct puffs_usermount *pu, int fd, int what)
+{
+
+	/* nada */
+}
+
+/* transfer file descriptor to master file server */
+static int
+sendfd(int s, int fd, int error)
+{
+	struct cmsghdr *cmp;
+	struct msghdr msg;
+	struct iovec iov;
+	ssize_t n;
+	int rv;
+
+	rv = 0;
+	cmp = emalloc(CMSG_LEN(sizeof(int)));
+
+	iov.iov_base = &error;
+	iov.iov_len = sizeof(int);
+
+	cmp->cmsg_level = SOL_SOCKET;
+	cmp->cmsg_type = SCM_RIGHTS;
+	cmp->cmsg_len = CMSG_LEN(sizeof(int));
+
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_control = cmp;
+	msg.msg_controllen = CMSG_LEN(sizeof(int));
+	*(int *)CMSG_DATA(cmp) = fd;
+
+	n = sendmsg(s, &msg, 0);
+	if (n == -1)
+		rv = errno;
+	else if (n < sizeof(int))
+		rv = EPROTO;
+
+	free(cmp);
+	return rv;
+}
+
+/*
+ * Produce I/O file descriptor by forking (like original portald).
+ * 
+ * child: run provider and transfer produced fd to parent
+ * parent: yield until child produces fd.  receive it and store it.
+ */
+static int
+provide(struct puffs_cc *pcc, struct portal_node *portn,
+	struct portal_cred *portc, char **v)
+{
+	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
+	struct puffs_framebuf *pufbuf;
+	int s[2];
+	int fd, error;
+	int data;
+
+	pufbuf = puffs_framebuf_make();
+	if (pufbuf == NULL)
+		return ENOMEM;
+
+	data = PUFBUF_FD;
+	if (puffs_framebuf_putdata(pufbuf, &data, sizeof(int)) == -1)
+		return errno;
+
+	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, s) == -1) {
+		puffs_framebuf_destroy(pufbuf);
+		return errno;
+	}
+
+	switch (fork()) {
+	case -1:
+		return errno;
+	case 0:
+		error = activate_argv(portc, portn->path, v, &fd);
+		sendfd(s[1], fd, error);
+		exit(0);
+	default:
+		puffs_framev_addfd(pu, s[0], PUFFS_FBIO_READ);
+		puffs_framev_enqueue_directreceive(pcc, s[0], pufbuf, 0);
+		puffs_framev_removefd(pu, s[0], 0);
+		close(s[0]);
+		close(s[1]);
+		if (puffs_framebuf_tellsize(pufbuf) != 2*sizeof(int)) {
+			puffs_framebuf_destroy(pufbuf);
+			return EIO;
+		}
+
+		puffs_framebuf_getdata_atoff(pufbuf, 0, &error, sizeof(int));
+		puffs_framebuf_getdata_atoff(pufbuf, sizeof(int),
+		    &fd, sizeof(int));
+		puffs_framebuf_destroy(pufbuf);
+
+		if (error)
+			return error;
+
+		data = 1;
+		if (ioctl(fd, FIONBIO, &data) == -1)
+			return errno;
+
+		if (puffs_framev_addfd(pu, fd, PUFFS_FBIO_WRITE) == -1)
+			return errno;
+
+		portn->fd = fd;
+		return 0;
+	}
 }
 
 int
@@ -140,6 +416,9 @@ main(int argc, char *argv[])
 
 	if (signal(SIGHUP, sighup) == SIG_ERR)
 		warn("cannot set sighup handler");
+	if (signal(SIGCHLD, sigcry) == SIG_ERR)
+		err(1, "cannot set sigchild handler");
+
 	readcfg = 0;
 	cfg = argv[0];
 	if (*cfg != '/')
@@ -149,6 +428,8 @@ main(int argc, char *argv[])
 		err(1, "cannot read cfg \"%s\"", cfg);
 
 	puffs_ml_setloopfn(pu, portal_loopfn);
+	puffs_framev_init(pu, portal_frame_rf, portal_frame_wf,
+	    NULL, portal_frame_notify);
 	if (puffs_mount(pu,  argv[1], mntflags, PORTAL_ROOT) == -1)
 		err(1, "mount");
 	if (puffs_mainloop(pu, lflags) == -1)
@@ -259,7 +540,6 @@ portal_node_open(struct puffs_cc *pcc, void *opc, int mode,
 	struct portal_node *portn = opc;
 	struct portal_cred portc;
 	char **v;
-	int fd;
 
 	if (opc == PORTAL_ROOT)
 		return 0;
@@ -269,29 +549,63 @@ portal_node_open(struct puffs_cc *pcc, void *opc, int mode,
 		return ENOENT;
 
 	credtr(&portc, pcr, mode);
-	if (activate_argv(&portc, portn->path, v, &fd) != 0)
+	return provide(pcc, portn, &portc, v);
-		return ENOENT;
-
-	portn->fd = fd;
-
-	return 0;
 }
 
 int
 portal_node_read(struct puffs_cc *pcc, void *opc, uint8_t *buf, off_t offset,
 	size_t *resid, const struct puffs_cred *pcr, int ioflag)
 {
+	struct puffs_usermount *pu = puffs_cc_getusermount(pcc);
 	struct portal_node *portn = opc;
-	ssize_t n;
+	struct puffs_framebuf *pufbuf;
+	size_t xfersize, winsize, boff;
+	void *win;
+	int rv, error;
+	int data;
 
 	assert(opc != PORTAL_ROOT);
+	error = 0;
 
-	n = read(portn->fd, buf, *resid);
+	/* if we can't (re-)enable it, treat it as EOF */
-	if (n == -1)
+	rv = puffs_framev_enablefd(pu, portn->fd, PUFFS_FBIO_READ);
-		return errno;
+	if (rv == -1)
+		return 0;
 
-	*resid -= n;
+	pufbuf = puffs_framebuf_make();
-	return 0;
+	data = PUFBUF_DATA;
+	puffs_framebuf_putdata(pufbuf, &data, sizeof(int));
+	puffs_framebuf_putdata(pufbuf, resid, sizeof(size_t));
+
+	rv = puffs_framev_enqueue_directreceive(pcc, portn->fd, pufbuf, 0);
+	if (rv == -1) {
+		error = errno;
+		goto out;
+	}
+
+	xfersize = puffs_framebuf_tellsize(pufbuf) - METADATASIZE;
+	*resid -= xfersize;
+	boff = 0;
+	do {
+		winsize = xfersize;
+		rv = puffs_framebuf_getwindow(pufbuf, METADATASIZE,
+		    &win, &winsize);
+		assert(rv == 0);
+		assert(winsize > 0);
+
+		memcpy(buf + boff, win, winsize);
+		xfersize -= winsize;
+		boff += winsize;
+	} while (xfersize);
+
+ out:
+	puffs_framev_disablefd(pu, portn->fd, PUFFS_FBIO_READ);
+	puffs_framebuf_destroy(pufbuf);
+
+	/* a trickery, from readdata() */
+	if (error == -1)
+		return 0;
+	return error;
 }
 
 int
@@ -299,15 +613,30 @@ portal_node_write(struct puffs_cc *pcc, void *opc, uint8_t *buf, off_t offset,
 	size_t *resid, const struct puffs_cred *pcr, int ioflag)
 {
 	struct portal_node *portn = opc;
-	ssize_t n;
+	struct puffs_framebuf *pufbuf;
+	size_t written;
+	int error, rv;
 
 	assert(opc != PORTAL_ROOT);
 
-	n = write(portn->fd, buf, *resid);
+	pufbuf = puffs_framebuf_make();
-	if (n == -1)
+	puffs_framebuf_putdata(pufbuf, buf, *resid);
-		return errno;
 
-	*resid -= n;
+	error = 0;
+	if (puffs_framev_enqueue_directsend(pcc, portn->fd, pufbuf, 0) == -1) {
+		error = errno;
+		goto out;
+	}
+
+	rv = puffs_framebuf_getdata_atoff(pufbuf, 0, &written, sizeof(size_t));
+	assert(rv == 0);
+	assert(written <= *resid);
+	*resid -= written;
+
+ out:
+	puffs_framebuf_destroy(pufbuf);
+	if (error == -1)
+		error = 0;
 	return 0;
 }
 
@@ -316,6 +645,9 @@ portal_node_inactive(struct puffs_cc *pcc, void *opc,
 	const struct puffs_cid *pcid)
 {
 
+	if (opc == PORTAL_ROOT)
+		return 0;
+
 	puffs_setback(pcc, PUFFS_SETBACK_NOREF_N1);
 	return 0;
 }