instead of messing about with pointer arithmetic, add an empty array

to the end of the defer structure. solves sizing and alignment concerns.

diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index ea4c716..775aedf 100644 (file)
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uipc_usrreq.c,v 1.99 2016/07/12 14:28:02 tedu Exp $   */
+/*     $OpenBSD: uipc_usrreq.c,v 1.100 2016/07/19 05:30:48 tedu Exp $  */
 /*     $NetBSD: uipc_usrreq.c,v 1.18 1996/02/09 19:00:50 christos Exp $        */
 
 /*
@@ -64,6 +64,7 @@ struct        unp_deferral {
        SLIST_ENTRY(unp_deferral)       ud_link;
        int     ud_n;
        /* followed by ud_n struct file * pointers */
+       struct file *ud_fp[];
 };
 
 /* list of sets of files that were sent over sockets that are now closed */
@@ -896,8 +897,7 @@ unp_gc(void *arg __unused)
        while ((defer = SLIST_FIRST(&unp_deferred)) != NULL) {
                SLIST_REMOVE_HEAD(&unp_deferred, ud_link);
                for (i = 0; i < defer->ud_n; i++) {
-                       memcpy(&fp, &((struct file **)(defer + 1))[i],
-                           sizeof(fp));
+                       fp = defer->ud_fp[i];
                        if (fp == NULL)
                                continue;
                        FREF(fp);
@@ -1059,7 +1059,7 @@ unp_discard(struct file **rp, int nfds)
        /* copy the file pointers to a deferral structure */
        defer = malloc(sizeof(*defer) + sizeof(*rp) * nfds, M_TEMP, M_WAITOK);
        defer->ud_n = nfds;
-       memcpy(defer + 1, rp, sizeof(*rp) * nfds);
+       memcpy(&defer->ud_fp[0], rp, sizeof(*rp) * nfds);
        memset(rp, 0, sizeof(*rp) * nfds);
        SLIST_INSERT_HEAD(&unp_deferred, defer, ud_link);