[Qemu-devel] [PULL 41/41] checkpatch: Detect newlines in error_report and other error functions

[Markus Armbruster]

From: "Jason J. Herne" <address@hidden>

We don't want newlines embedded in error messages. This seems to be a common
problem with new code so let's try to catch it with checkpatch.

This will not catch cases where newlines are inserted into the middle of an
existing multi-line statement. But those cases should be rare.

Signed-off-by: Jason J. Herne <address@hidden>
Message-Id: <address@hidden>
[Rephrased "Error function text" to "Error messages", dropped
error_vprintf, error_printf, error_printf from $qemu_error_funcs,
because they may legitimately print newlines]
Signed-off-by: Markus Armbruster <address@hidden>
---
 scripts/checkpatch.pl | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index efca817..257126f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2498,6 +2498,42 @@ sub process {
                        WARN("use QEMU instead of Qemu or QEmu\n" . $herecurr);
                }
 
+# Qemu error function tests
+
+       # Find newlines in error messages
+       my $qemu_error_funcs = qr{error_setg|
+                               error_setg_errno|
+                               error_setg_win32|
+                               error_set|
+                               error_vreport|
+                               error_report}x;
+
+       if ($rawline =~ /\b(?:$qemu_error_funcs)\s*\(\s*\".*\\n/) {
+               WARN("Error messages should not contain newlines\n" . 
$herecurr);
+       }
+
+       # Continue checking for error messages that contains newlines. This
+       # check handles cases where string literals are spread over multiple 
lines.
+       # Example:
+       # error_report("Error msg line #1"
+       #              "Error msg line #2\n");
+       my $quoted_newline_regex = qr{\+\s*\".*\\n.*\"};
+       my $continued_str_literal = qr{\+\s*\".*\"};
+
+       if ($rawline =~ /$quoted_newline_regex/) {
+               # Backtrack to first line that does not contain only a quoted 
literal
+               # and assume that it is the start of the statement.
+               my $i = $linenr - 2;
+
+               while (($i >= 0) & $rawlines[$i] =~ /$continued_str_literal/) {
+                       $i--;
+               }
+
+               if ($rawlines[$i] =~ /\b(?:$qemu_error_funcs)\s*\(/) {
+                       WARN("Error messages should not contain newlines\n" . 
$herecurr);
+               }
+       }
+
 # check for non-portable ffs() calls that have portable alternatives in QEMU
                if ($line =~ /\bffs\(/) {
                        ERROR("use ctz32() instead of ffs()\n" . $herecurr);
-- 
2.4.3