[src/trunk]: src/sys/arch/alpha/alpha qemu_find_rootdev(): Zero the buffer th...

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

details:   https://anonhg.NetBSD.org/src/rev/962a0d861e6b
branches:  trunk
changeset: 1021270:962a0d861e6b
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat May 22 15:04:33 2021 +0000

description:
qemu_find_rootdev(): Zero the buffer that we use to fetch the Qemu
"prom" root device variable; junk past the trailing NUL would cause
the way we parse the string to fail.  Also parse rootdev= and root=
the same way ("be liberal in what you accept" approach).

diffstat:

 sys/arch/alpha/alpha/autoconf.c |  60 +++++++++++++++++++++-------------------
 1 files changed, 31 insertions(+), 29 deletions(-)

diffs (95 lines):

diff -r 485704ed28c4 -r 962a0d861e6b sys/arch/alpha/alpha/autoconf.c
--- a/sys/arch/alpha/alpha/autoconf.c   Sat May 22 13:43:50 2021 +0000
+++ b/sys/arch/alpha/alpha/autoconf.c   Sat May 22 15:04:33 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: autoconf.c,v 1.55 2020/10/03 17:31:46 thorpej Exp $ */
+/* $NetBSD: autoconf.c,v 1.56 2021/05/22 15:04:33 thorpej Exp $ */
 
 /*
  * Copyright (c) 1992, 1993
@@ -42,7 +42,7 @@
 
 #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: autoconf.c,v 1.55 2020/10/03 17:31:46 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: autoconf.c,v 1.56 2021/05/22 15:04:33 thorpej Exp $");
 
 #include "pci.h"
 
@@ -100,11 +100,22 @@
 static void
 qemu_find_rootdev(void)
 {
-       char buf[32];
+       char buf[32] = { 0 };
 
        /*
         * Check for "rootdev=wd0".
         */
+       if (! prom_qemu_getenv("rootdev", buf, sizeof(buf))) {
+               /*
+                * Check "root=/dev/wd0a", "root=/dev/hda1", etc.
+                */
+               if (! prom_qemu_getenv("root", buf, sizeof(buf))) {
+                       printf("WARNING: no rootdev= or root= arguments "
+                              "provided by Qemu\n");
+                       return;
+               }
+       }
+
        if (prom_qemu_getenv("rootdev", buf, sizeof(buf))) {
                snprintf(bootinfo.booted_dev, sizeof(bootinfo.booted_dev),
                    "rootdev=%s", buf);
@@ -112,35 +123,26 @@
                return;
        }
 
-       /*
-        * Check for "root=/dev/wd0a", "root=/dev/hda1", etc.
-        */
-       if (prom_qemu_getenv("root", buf, sizeof(buf))) {
-               const size_t devlen = strlen("/dev/");
-               const char *cp = buf;
-               char *ecp = &buf[sizeof(buf) - 1];
-
-               snprintf(bootinfo.booted_dev, sizeof(bootinfo.booted_dev),
-                   "root=%s", buf);
+       const size_t devlen = strlen("/dev/");
+       const char *cp = buf;
+       char *ecp = &buf[sizeof(buf) - 1];
 
-               /* Find the start of the device xname. */
-               if (strlen(cp) > devlen && strncmp(cp, "/dev/", devlen) == 0) {
-                       cp += devlen;
-               }
-
-               /* Now strip any partition letter off the end. */
-               while (ecp != cp) {
-                       if (*ecp >= '0' && *ecp <= '9') {
-                               break;
-                       }
-                       *ecp-- = '\0';
-               }
-
-               booted_device = device_find_by_xname(cp);
-               return;
+       /* Find the start of the device xname. */
+       if (strlen(cp) > devlen && strncmp(cp, "/dev/", devlen) == 0) {
+               cp += devlen;
        }
 
-       printf("WARNING: no rootdev= or root= arguments provided by Qemu\n");
+       /* Now strip any partition letter off the end. */
+       while (ecp != cp) {
+               if (*ecp >= '0' && *ecp <= '9') {
+                       break;
+               }
+               *ecp-- = '\0';
+       }
+
+       snprintf(bootinfo.booted_dev, sizeof(bootinfo.booted_dev),
+           "root=%s", cp);
+       booted_device = device_find_by_xname(cp);
 }
 
 void