[src/trunk]: src/sys/kern simplify unp_externalize(), some from gimpy, some f...

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

details:   https://anonhg.NetBSD.org/src/rev/607a9e4b7119
branches:  trunk
changeset: 780575:607a9e4b7119
user:      christos <christos%NetBSD.org@localhost>
date:      Mon Jul 30 10:42:24 2012 +0000

description:
simplify unp_externalize(), some from gimpy, some from me.

diffstat:

 sys/kern/uipc_usrreq.c |  87 +++++++++++++++++++++++++------------------------
 1 files changed, 45 insertions(+), 42 deletions(-)

diffs (165 lines):

diff -r 0b02f68767fc -r 607a9e4b7119 sys/kern/uipc_usrreq.c
--- a/sys/kern/uipc_usrreq.c    Mon Jul 30 10:25:24 2012 +0000
+++ b/sys/kern/uipc_usrreq.c    Mon Jul 30 10:42:24 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uipc_usrreq.c,v 1.137 2012/06/02 16:16:16 martin Exp $ */
+/*     $NetBSD: uipc_usrreq.c,v 1.138 2012/07/30 10:42:24 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 1.137 2012/06/02 16:16:16 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.138 2012/07/30 10:42:24 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1235,25 +1235,22 @@
 int
 unp_externalize(struct mbuf *rights, struct lwp *l, int flags)
 {
-       struct cmsghdr *cm = mtod(rights, struct cmsghdr *);
-       struct proc *p = l->l_proc;
-       int i, *fdp;
+       struct cmsghdr * const cm = mtod(rights, struct cmsghdr *);
+       struct proc * const p = l->l_proc;
        file_t **rp;
-       file_t *fp;
-       int nfds, error = 0;
+       int error = 0;
 
-       nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) /
+       const size_t nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) /
            sizeof(file_t *);
-       rp = (file_t **)CMSG_DATA(cm);
 
-       fdp = malloc(nfds * sizeof(int), M_TEMP, M_WAITOK);
+       int * const fdp = kmem_alloc(nfds * sizeof(int), KM_SLEEP);
        rw_enter(&p->p_cwdi->cwdi_lock, RW_READER);
 
        /* Make sure the recipient should be able to see the files.. */
        if (p->p_cwdi->cwdi_rdir != NULL) {
                rp = (file_t **)CMSG_DATA(cm);
-               for (i = 0; i < nfds; i++) {
-                       fp = *rp++;
+               for (size_t i = 0; i < nfds; i++) {
+                       file_t * const fp = *rp++;
                        /*
                         * If we are in a chroot'ed directory, and
                         * someone wants to pass us a directory, make
@@ -1265,7 +1262,7 @@
                                if ((vp->v_type == VDIR) &&
                                    !vn_isunder(vp, p->p_cwdi->cwdi_rdir, l)) {
                                        error = EPERM;
-                                       break;
+                                       goto out;
                                }
                        }
                }
@@ -1273,40 +1270,30 @@
 
  restart:
        rp = (file_t **)CMSG_DATA(cm);
-       if (error != 0) {
-               for (i = 0; i < nfds; i++) {
-                       fp = *rp;
-                       *rp++ = 0;
-                       unp_discard_now(fp);
-               }
-               goto out;
-       }
-
        /*
         * First loop -- allocate file descriptor table slots for the
         * new files.
         */
-       for (i = 0; i < nfds; i++) {
-               fp = *rp++;
+       for (size_t i = 0; i < nfds; i++) {
                if ((error = fd_alloc(p, 0, &fdp[i])) != 0) {
                        /*
                         * Back out what we've done so far.
                         */
-                       for (--i; i >= 0; i--) {
+                       while (i-- > 0) {
                                fd_abort(p, NULL, fdp[i]);
                        }
                        if (error == ENOSPC) {
                                fd_tryexpand(p);
                                error = 0;
-                       } else {
-                               /*
-                                * This is the error that has historically
-                                * been returned, and some callers may
-                                * expect it.
-                                */
-                               error = EMSGSIZE;
+                               goto restart;
                        }
-                       goto restart;
+                       /*
+                        * This is the error that has historically
+                        * been returned, and some callers may
+                        * expect it.
+                        */
+                       error = EMSGSIZE;
+                       goto out;
                }
        }
 
@@ -1315,12 +1302,17 @@
         * file passing state and affix the descriptors.
         */
        rp = (file_t **)CMSG_DATA(cm);
-       for (i = 0; i < nfds; i++) {
-               int fd = fdp[i];
-               fp = *rp++;
+       int *ofdp = (int *)CMSG_DATA(cm);
+       for (size_t i = 0; i < nfds; i++) {
+               file_t * const fp = *rp++;
+               const int fd = fdp[i];
                atomic_dec_uint(&unp_rights);
                fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0);
                fd_affix(p, fp, fd);
+               /*
+                * Done with this file pointer, replace it with a fd;
+                */
+               *ofdp++ = fd;
                mutex_enter(&fp->f_lock);
                fp->f_msgcount--;
                mutex_exit(&fp->f_lock);
@@ -1334,15 +1326,26 @@
        }
 
        /*
-        * Copy temporary array to message and adjust length, in case of
-        * transition from large file_t pointers to ints.
+        * Adjust length, in case of transition from large file_t
+        * pointers to ints.
         */
-       memcpy(CMSG_DATA(cm), fdp, nfds * sizeof(int));
-       cm->cmsg_len = CMSG_LEN(nfds * sizeof(int));
-       rights->m_len = CMSG_SPACE(nfds * sizeof(int));
+       if (sizeof(file_t *) != sizeof(int)) {
+               cm->cmsg_len = CMSG_LEN(nfds * sizeof(int));
+               rights->m_len = CMSG_SPACE(nfds * sizeof(int));
+       }
  out:
+       if (__predict_false(error != 0)) {
+               rp = (file_t **)CMSG_DATA(cm);
+               for (size_t i = 0; i < nfds; i++) {
+                       file_t * const fp = *rp;
+                       *rp++ = 0;
+                       unp_discard_now(fp);
+               }
+               goto out;
+       }
+
        rw_exit(&p->p_cwdi->cwdi_lock);
-       free(fdp, M_TEMP);
+       kmem_free(fdp, nfds * sizeof(int));
        return (error);
 }