[src/trunk]: src/sys/kern Centralize the sockaddr_un allocation code. Set sun...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/387f2c5bdbd3
branches:  trunk
changeset: 790430:387f2c5bdbd3
user:      christos <christos%NetBSD.org@localhost>
date:      Tue Oct 08 17:21:24 2013 +0000

description:
Centralize the sockaddr_un allocation code. Set sun_len appropriately so
that the address length returned is correct, not always 106. Note that
we do things slightly differently than linux and explain why. Unit-tests
to come.

diffstat:

 sys/kern/uipc_usrreq.c |  49 +++++++++++++++++++++++++++----------------------
 1 files changed, 27 insertions(+), 22 deletions(-)

diffs (85 lines):

diff -r 8b9cf274dcc1 -r 387f2c5bdbd3 sys/kern/uipc_usrreq.c
--- a/sys/kern/uipc_usrreq.c    Tue Oct 08 15:09:51 2013 +0000
+++ b/sys/kern/uipc_usrreq.c    Tue Oct 08 17:21:24 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uipc_usrreq.c,v 1.145 2013/10/08 15:09:51 christos Exp $       */
+/*     $NetBSD: uipc_usrreq.c,v 1.146 2013/10/08 17:21:24 christos Exp $       */
 
 /*-
  * Copyright (c) 1998, 2000, 2004, 2008, 2009 The NetBSD Foundation, Inc.
@@ -96,7 +96,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.145 2013/10/08 15:09:51 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.146 2013/10/08 17:21:24 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -882,6 +882,29 @@
                unp_free(unp);
 }
 
+/*
+ * Allocate the new sockaddr.  We have to allocate one
+ * extra byte so that we can ensure that the pathname
+ * is nul-terminated. Note that unlike linux, we don't
+ * include in the address length the NUL in the path
+ * component, because doing so, would exceed sizeof(sockaddr_un)
+ * for fully occupied pathnames. Linux is also inconsistent,
+ * because it does not include the NUL in the length of
+ * what it calls "abstract" unix sockets.
+ */
+static struct sockaddr_un *
+makeun(struct mbuf *nam, size_t *addrlen) {
+       struct sockaddr_un *sun;
+
+       *addrlen = nam->m_len + 1;
+       sun = malloc(*addrlen, M_SONAME, M_WAITOK);
+       m_copydata(nam, 0, nam->m_len, (void *)sun);
+       *(((char *)sun) + nam->m_len) = '\0';
+       sun->sun_len = strlen(sun->sun_path) +
+           offsetof(struct sockaddr_un, sun_path);
+       return sun;
+}
+
 int
 unp_bind(struct socket *so, struct mbuf *nam, struct lwp *l)
 {
@@ -908,16 +931,8 @@
        unp->unp_flags |= UNP_BUSY;
        sounlock(so);
 
-       /*
-        * Allocate the new sockaddr.  We have to allocate one
-        * extra byte so that we can ensure that the pathname
-        * is nul-terminated.
-        */
        p = l->l_proc;
-       addrlen = nam->m_len + 1;
-       sun = malloc(addrlen, M_SONAME, M_WAITOK);
-       m_copydata(nam, 0, nam->m_len, (void *)sun);
-       *(((char *)sun) + nam->m_len) = '\0';
+       sun = makeun(nam, &addrlen);
 
        pb = pathbuf_create(sun->sun_path);
        if (pb == NULL) {
@@ -996,17 +1011,7 @@
        unp->unp_flags |= UNP_BUSY;
        sounlock(so);
 
-       /*
-        * Allocate a temporary sockaddr.  We have to allocate one extra
-        * byte so that we can ensure that the pathname is nul-terminated.
-        * When we establish the connection, we copy the other PCB's
-        * sockaddr to our own.
-        */
-       addrlen = nam->m_len + 1;
-       sun = malloc(addrlen, M_SONAME, M_WAITOK);
-       m_copydata(nam, 0, nam->m_len, (void *)sun);
-       *(((char *)sun) + nam->m_len) = '\0';
-
+       sun = makeun(nam, &addrlen);
        pb = pathbuf_create(sun->sun_path);
        if (pb == NULL) {
                error = ENOMEM;