From: Karel Zak <kzak@redhat.com>
Date: Thu, 6 May 2021 14:35:50 +0000 (+0200)
Subject: lib/jsonwrt: don't use ctype.h for ASCII chars
X-Git-Tag: v2.37-rc2~16
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=64a89adaa16461bd58730c1408b30aa7244b4f66;p=thirdparty%2Futil-linux.git

lib/jsonwrt: don't use ctype.h for ASCII chars

tolower() does not work "as expected" for tr_TR.UTF-8 (Turkish).
Fortunately, we need to convert only objects and variables names in
JSON output, and this is always old good ASCII.

Anyway, for more details:

	$ cat a.c
	#include <ctype.h>
	#include <stdio.h>
	#include <locale.h>

	int main(void)
	{
		int in, out;

		setlocale(LC_ALL, "");

		in ='I';
		out = tolower(in);

		printf("%1$c [%1$d] --> %2$c [%2$d]\n", in, out);
		return 0;
	}

	$ make a
	cc     a.c   -o a

	$ LANG=en_US.utf8 ./a
	I [73] --> i [105]

	$ LANG=tr_TR.UTF-8 ./a
	I [73] --> I [73]

Fixes: https://github.com/karelzak/util-linux/issues/1302
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/lib/jsonwrt.c b/lib/jsonwrt.c
index 92d64f7464..f2003e8083 100644
--- a/lib/jsonwrt.c
+++ b/lib/jsonwrt.c
@@ -8,6 +8,8 @@
  */
 #include <stdio.h>
 #include <inttypes.h>
+#include <ctype.h>
+#include <cctype.h>
 
 #include "c.h"
 #include "jsonwrt.h"
@@ -31,7 +33,7 @@ static void fputs_quoted_case_json(const char *data, FILE *out, int dir)
 	fputc('"', out);
 	for (p = data; p && *p; p++) {
 
-		const unsigned char c = (unsigned char) *p;
+		const unsigned int c = (unsigned int) *p;
 
 		/* From http://www.json.org
 		 *
@@ -49,8 +51,17 @@ static void fputs_quoted_case_json(const char *data, FILE *out, int dir)
 
 		/* All non-control characters OK; do the case swap as required. */
 		if (c >= 0x20) {
-			fputc(dir ==  1 ? toupper(c) :
-			      dir == -1 ? tolower(c) : *p, out);
+			/*
+			 * Don't use locale sensitive ctype.h functions for regular
+			 * ASCII chars, because for example with Turkish locale
+			 * (aka LANG=tr_TR.UTF-8) toupper('I') returns 'I'.
+			 */
+			if (c <= 127)
+				fputc(dir ==  1 ? c_toupper(c) :
+				      dir == -1 ? c_tolower(c) : *p, out);
+			else
+				fputc(dir ==  1 ? toupper(c) :
+				      dir == -1 ? tolower(c) : *p, out);
 			continue;
 		}