ash: fix matching of unicode greek letter rho (cf 81) and similar cases

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/ash.c

@@ -5913,6 +5913,7 @@ rmescapes(char *str, int flag)
 	while (*p) {
 		if ((unsigned char)*p == CTLQUOTEMARK) {
 // Note: both inquotes and protect_against_glob only affect whether
+// CTLESC,<ch> gets converted to <ch> or to \<ch>
 			inquotes = ~inquotes;
 			p++;
 			protect_against_glob = globbing;
@@ -5925,8 +5926,28 @@ rmescapes(char *str, int flag)
 				ash_msg_and_raise_error("CTLESC at EOL (shouldn't happen)");
 #endif
 			if (protect_against_glob) {
+				/*
+				 * We used to trust glob() and fnmatch() to eat
+				 * superfluous escapes (\z where z has no
+				 * special meaning anyway). But this causes
+				 * bugs such as string of one greek letter rho
+				 * (unicode-encoded as two bytes 'cf,81")
+				 * getting encoded as "cf,CTLESC,81"
+				 * and here, converted to "cf,\,81" -
+				 * which does not go well with some flavors
+				 * of fnmatch() in unicode locales.
+				 *
+				 * Lets add "\" only on the chars which need it.
+				 */
+				if (*p == '*'
+				 || *p == '?'
+				 || *p == '['
+				/* || *p == ']' maybe also this? */
+				 || *p == '\\'
+				) {
 					*q++ = '\\';
 				}
+			}
 		} else if (*p == '\\' && !inquotes) {
 			/* naked back slash */
 			protect_against_glob = 0;

shell/ash_test/ash-quoting/unicode_8x_chars.right

@@ -0,0 +1,6 @@
+ok
+ok
+ok
+ok
+ok
+ok

shell/ash_test/ash-quoting/unicode_8x_chars.tests

@@ -0,0 +1,28 @@
+# Unicode: cf 80
+case π in
+( "π" ) echo ok ;;
+( * )   echo WRONG ;;
+esac
+# Unicode: cf 81
+case ρ in
+( "ρ" ) echo ok ;;
+( * )   echo WRONG ;;
+esac
+# Unicode: cf 82
+case ς in
+( "ς" ) echo ok ;;
+( * )   echo WRONG ;;
+esac
+
+case "π" in
+( π ) echo ok ;;
+( * ) echo WRONG ;;
+esac
+case "ρ" in
+( ρ ) echo ok ;;
+( * ) echo WRONG ;;
+esac
+case "ς" in
+( ς ) echo ok ;;
+( * ) echo WRONG ;;
+esac

shell/hush_test/hush-quoting/unicode_8x_chars.right

@@ -0,0 +1,6 @@
+ok
+ok
+ok
+ok
+ok
+ok

shell/hush_test/hush-quoting/unicode_8x_chars.tests

@@ -0,0 +1,28 @@
+# Unicode: cf 80
+case π in
+( "π" ) echo ok ;;
+( * )   echo WRONG ;;
+esac
+# Unicode: cf 81
+case ρ in
+( "ρ" ) echo ok ;;
+( * )   echo WRONG ;;
+esac
+# Unicode: cf 82
+case ς in
+( "ς" ) echo ok ;;
+( * )   echo WRONG ;;
+esac
+
+case "π" in
+( π ) echo ok ;;
+( * ) echo WRONG ;;
+esac
+case "ρ" in
+( ρ ) echo ok ;;
+( * ) echo WRONG ;;
+esac
+case "ς" in
+( ς ) echo ok ;;
+( * ) echo WRONG ;;
+esac