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Date:      Sun, 14 Apr 2013 17:08:34 +0000 (UTC)
From:      Mateusz Guzik <mjg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r249480 - in head/sys: kern sys
Message-ID:  <201304141708.r3EH8Y4A057048@svn.freebsd.org>
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Author: mjg
Date: Sun Apr 14 17:08:34 2013
New Revision: 249480
URL: http://svnweb.freebsd.org/changeset/base/249480

Log:
  Add fdallocn function and use it when passing fds over unix socket.
  
  This gets rid of "unp_externalize fdalloc failed" panic.
  
  Reviewed by:	pjd
  MFC after:	1 week

Modified:
  head/sys/kern/kern_descrip.c
  head/sys/kern/uipc_usrreq.c
  head/sys/sys/filedesc.h

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Sun Apr 14 16:49:27 2013	(r249479)
+++ head/sys/kern/kern_descrip.c	Sun Apr 14 17:08:34 2013	(r249480)
@@ -1582,6 +1582,34 @@ fdalloc(struct thread *td, int minfd, in
 }
 
 /*
+ * Allocate n file descriptors for the process.
+ */
+int
+fdallocn(struct thread *td, int minfd, int *fds, int n)
+{
+	struct proc *p = td->td_proc;
+	struct filedesc *fdp = p->p_fd;
+	int i;
+
+	FILEDESC_XLOCK_ASSERT(fdp);
+
+	if (!fdavail(td, n))
+		return (EMFILE);
+
+	for (i = 0; i < n; i++)
+		if (fdalloc(td, 0, &fds[i]) != 0)
+			break;
+
+	if (i < n) {
+		for (i--; i >= 0; i--)
+			fdunused(fdp, fds[i]);
+		return (EMFILE);
+	}
+
+	return (0);
+}
+
+/*
  * Check to see whether n user file descriptors are available to the process
  * p.
  */

Modified: head/sys/kern/uipc_usrreq.c
==============================================================================
--- head/sys/kern/uipc_usrreq.c	Sun Apr 14 16:49:27 2013	(r249479)
+++ head/sys/kern/uipc_usrreq.c	Sun Apr 14 17:08:34 2013	(r249480)
@@ -1706,7 +1706,6 @@ unp_externalize(struct mbuf *control, st
 	void *data;
 	socklen_t clen = control->m_len, datalen;
 	int error, newfds;
-	int f;
 	u_int newlen;
 
 	UNP_LINK_UNLOCK_ASSERT();
@@ -1732,13 +1731,6 @@ unp_externalize(struct mbuf *control, st
 				goto next;
 			}
 			FILEDESC_XLOCK(fdesc);
-			/* if the new FD's will not fit free them.  */
-			if (!fdavail(td, newfds)) {
-				FILEDESC_XUNLOCK(fdesc);
-				error = EMSGSIZE;
-				unp_freerights(fdep, newfds);
-				goto next;
-			}
 
 			/*
 			 * Now change each pointer to an fd in the global
@@ -1758,17 +1750,22 @@ unp_externalize(struct mbuf *control, st
 
 			fdp = (int *)
 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
+			if (fdallocn(td, 0, fdp, newfds) != 0) {
+				FILEDESC_XUNLOCK(td->td_proc->p_fd);
+				error = EMSGSIZE;
+				unp_freerights(fdep, newfds);
+				m_freem(*controlp);
+				*controlp = NULL;
+				goto next;
+			}
 			for (i = 0; i < newfds; i++, fdp++) {
-				if (fdalloc(td, 0, &f))
-					panic("unp_externalize fdalloc failed");
-				fde = &fdesc->fd_ofiles[f];
+				fde = &fdesc->fd_ofiles[*fdp];
 				fde->fde_file = fdep[0]->fde_file;
 				filecaps_move(&fdep[0]->fde_caps,
 				    &fde->fde_caps);
 				if ((flags & MSG_CMSG_CLOEXEC) != 0)
 					fde->fde_flags |= UF_EXCLOSE;
 				unp_externalize_fp(fde->fde_file);
-				*fdp = f;
 			}
 			FILEDESC_XUNLOCK(fdesc);
 			free(fdep[0], M_FILECAPS);

Modified: head/sys/sys/filedesc.h
==============================================================================
--- head/sys/sys/filedesc.h	Sun Apr 14 16:49:27 2013	(r249479)
+++ head/sys/sys/filedesc.h	Sun Apr 14 17:08:34 2013	(r249480)
@@ -150,6 +150,7 @@ int	falloc_noinstall(struct thread *td, 
 int	finstall(struct thread *td, struct file *fp, int *resultfp, int flags,
 	    struct filecaps *fcaps);
 int	fdalloc(struct thread *td, int minfd, int *result);
+int	fdallocn(struct thread *td, int minfd, int *fds, int n);
 int	fdavail(struct thread *td, int n);
 int	fdcheckstd(struct thread *td);
 void	fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td);

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