[PATCH v2 2/3] bootconfig: Trim unquoted values at end of file

[Eduardo Mucelli Rezende Oliveira <edumucelli@gmail.com>]

__xbc_parse_value() trims an unquoted value when it encounters a
delimiter, but leaves trailing whitespace intact when it reaches the end
of the input. Thus "key = value   " has a different value depending on
whether the file ends with a newline. The extra whitespace also reaches
the rendered kernel command line.

Trim unquoted values after the scan finishes, including at end of input.
Skip trimming after a closing quote so intentional whitespace in quoted
values remains unchanged. Add checks for scalars, arrays and quoted
values without a final newline.

Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support")
Signed-off-by: Eduardo Mucelli Rezende Oliveira <edumucelli@gmail.com>
---
I tested inputs ending in unquoted spaces, tabs and carriage returns,
including arrays and appended or overridden values. The checks compare
the parser's actual values and the tool's rendered kernel command line.
Quoted whitespace and inputs ending in delimiters are controls.

The original parser fails nine of the 18 focused checks. With the fix,
all 18 pass, independently and in the combined series. The full
bootconfig test suite also passes with the regression checks added.

 lib/bootconfig.c                    |  5 +++--
 tools/bootconfig/test-bootconfig.sh | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 819685d6c68d..bd071c394c36 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -793,16 +793,17 @@ static int __init __xbc_parse_value(char **__v, char **__n)
 				return xbc_parse_error("No value delimiter", p);
 			if (*p)
 				p++;
-			break;
+			goto skip_trim;
 		}
 		if (strchr(",;\n#}", c)) {
 			*p++ = '\0';
-			v = strim(v);
 			break;
 		}
 	}
 	if (quotes)
 		return xbc_parse_error("No closing quotes", p);
+	v = strim(v);
+skip_trim:
 	if (c == '#') {
 		p = skip_comment(p);
 		c = '\n';	/* A comment must be treated as a newline */
diff --git a/tools/bootconfig/test-bootconfig.sh b/tools/bootconfig/test-bootconfig.sh
index 530ce7e28d63..a2e8311d4d19 100755
--- a/tools/bootconfig/test-bootconfig.sh
+++ b/tools/bootconfig/test-bootconfig.sh
@@ -171,6 +171,24 @@ $BOOTCONF $INITRD > $OUTFILE
 xfail grep -q 'val[[:space:]]' $OUTFILE
 xpass grep -q 'val2[[:space:]]' $OUTFILE
 
+echo "Remove unquoted trailing whitespace at end of file"
+printf 'foo = val \t' > $TEMPCONF
+$BOOTCONF -l $TEMPCONF > $OUTFILE
+printf 'foo = "val"\n' > $TEMPCONF
+xpass cmp $TEMPCONF $OUTFILE
+
+echo "Remove trailing whitespace from the last array value at end of file"
+printf 'foo = first, last \t' > $TEMPCONF
+$BOOTCONF -l $TEMPCONF > $OUTFILE
+printf 'foo = "first", "last"\n' > $TEMPCONF
+xpass cmp $TEMPCONF $OUTFILE
+
+echo "Keep quoted trailing whitespace at end of file"
+printf 'foo = "val "' > $TEMPCONF
+$BOOTCONF -l $TEMPCONF > $OUTFILE
+printf 'foo = "val "\n' > $TEMPCONF
+xpass cmp $TEMPCONF $OUTFILE
+
 echo "Showing correct line:column of no closing brace"
 cat > $TEMPCONF << EOF
 foo {
-- 
2.53.0