[src/trunk]: src/sys/lib/libsa Support loading boot.cfg from non file-system ...

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

details:   https://anonhg.NetBSD.org/src/rev/41fa19aca5c2
branches:  trunk
changeset: 973345:41fa19aca5c2
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sat Jun 27 17:22:12 2020 +0000

description:
Support loading boot.cfg from non file-system based devices.

diffstat:

 sys/lib/libsa/bootcfg.c |  14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diffs (46 lines):

diff -r 9680abb311b5 -r 41fa19aca5c2 sys/lib/libsa/bootcfg.c
--- a/sys/lib/libsa/bootcfg.c   Sat Jun 27 17:07:49 2020 +0000
+++ b/sys/lib/libsa/bootcfg.c   Sat Jun 27 17:22:12 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bootcfg.c,v 1.4 2019/03/31 20:08:45 christos Exp $     */
+/*     $NetBSD: bootcfg.c,v 1.5 2020/06/27 17:22:12 jmcneill Exp $     */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -99,7 +99,7 @@
 {
        char *bc, *c;
        int cmenu, cbanner;
-       ssize_t len, off;
+       ssize_t len, off, resid;
        int fd, err;
        struct stat st;
        char *next, *key, *value, *v2;
@@ -119,8 +119,8 @@
 
        err = fstat(fd, &st);
        if (err == -1) {
-               close(fd);
-               return EIO;
+               /* file descriptor may not be backed by a libsa file-system */
+               st.st_size = maxsz;
        }
 
        /* if a maximum size is being requested for the boot.cfg enforce it. */
@@ -146,12 +146,14 @@
         *       the storage anyway.
         */
        off = 0;
+       resid = st.st_size;
        do {
-               len = read(fd, bc + off, 1024);
+               len = read(fd, bc + off, uimin(1024, resid));
                if (len <= 0)
                        break;
                off += len;
-       } while (len > 0);
+               resid -= len;
+       } while (len > 0 && resid > 0);
        bc[off] = '\0';
 
        close(fd);