ash: move parse-time quote flag detection to run-time

Because the parser does not recursively parse parameter expansion
with respect to quotes, we can't accurately determine quote status at
parse time.  This patch works around this by moving the quote detection
to run-time where we do interpret it recursively.

Test case:
   foo=\\ echo "<${foo#[\\]}>"
Old result:
   <\>
New result:
   <>

Do not quote back slashes in parameter expansions outside quotes.

Test case:
   a=/b/c/*
   b=\\
   echo ${a%$b*}
Old result:
   /b/c/*
New result:
   /b/c/

Based on commits 880d952, 7cfd8be, 0d7d660 and a7c21a6 from
git://git.kernel.org/pub/scm/utils/dash/dash.git by Herbert Xu

function                                             old     new   delta
argstr                                              1164    1193     +29
memtodest                                            147     174     +27
subevalvar                                          1153    1177     +24
redirect                                            1279    1282      +3
dolatstr                                               5       7      +2
static.spclchars                                      10       9      -1
expandarg                                            962     960      -2
evalcase                                             273     271      -2
evalcommand                                         1204    1197      -7
rmescapes                                            236     227      -9
preglob                                               27       8     -19
evalvar                                              604     582     -22
cmdputs                                              389     334     -55
readtoken1                                          3163    3061    -102
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/9 up/down: 85/-219)          Total: -134 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

5 files changed, 72 insertions, 98 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 33a477d80..e7e70817f 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -598,8 +598,6 @@ out2str(const char *p)
 #define CTLVAR       ((unsigned char)'\202')    /* variable defn */
 #define CTLENDVAR    ((unsigned char)'\203')
 #define CTLBACKQ     ((unsigned char)'\204')
-#define CTLQUOTE 01             /* ored with CTLBACKQ code if in quotes */
-/*      CTLBACKQ | CTLQUOTE == '\205' */
 #define CTLARI       ((unsigned char)'\206')    /* arithmetic expression */
 #define CTLENDARI    ((unsigned char)'\207')
 #define CTLQUOTEMARK ((unsigned char)'\210')
@@ -608,7 +606,6 @@ out2str(const char *p)
 /* variable substitution byte (follows CTLVAR) */
 #define VSTYPE  0x0f            /* type of variable substitution */
 #define VSNUL   0x10            /* colon--treat the empty string as unset */
-#define VSQUOTE 0x80            /* inside double quotes--suppress splitting */
 
 /* values of VSTYPE field */
 #define VSNORMAL        0x1     /* normal variable:  $var or ${var} */
@@ -628,8 +625,9 @@ out2str(const char *p)
 #endif
 
 static const char dolatstr[] ALIGN1 = {
-	CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
+	CTLQUOTEMARK, CTLVAR, VSNORMAL, '@', '=', CTLQUOTEMARK, '\0'
 };
+#define DOLATSTRLEN 6
 
 #define NCMD      0
 #define NPIPE     1
@@ -865,9 +863,7 @@ trace_puts_quoted(char *s)
 		case '\\': c = '\\'; goto backslash;
 		case CTLESC: c = 'e'; goto backslash;
 		case CTLVAR: c = 'v'; goto backslash;
-		case CTLVAR+CTLQUOTE: c = 'V'; goto backslash;
 		case CTLBACKQ: c = 'q'; goto backslash;
-		case CTLBACKQ+CTLQUOTE: c = 'Q'; goto backslash;
  backslash:
 			putc('\\', tracefile);
 			putc(c, tracefile);
@@ -1030,7 +1026,6 @@ sharg(union node *arg, FILE *fp)
 			putc('}', fp);
 			break;
 		case CTLBACKQ:
-		case CTLBACKQ|CTLQUOTE:
 			putc('$', fp);
 			putc('(', fp);
 			shtree(bqlist->n, -1, NULL, fp);
@@ -4413,11 +4408,7 @@ cmdputs(const char *s)
 				str = "${#";
 			else
 				str = "${";
-			if (!(subtype & VSQUOTE) == !(quoted & 1))
-				goto dostr;
-			quoted ^= 1;
-			c = '"';
-			break;
+			goto dostr;
 		case CTLENDVAR:
 			str = "\"}" + !(quoted & 1);
 			quoted >>= 1;
@@ -4426,9 +4417,6 @@ cmdputs(const char *s)
 		case CTLBACKQ:
 			str = "$(...)";
 			goto dostr;
-		case CTLBACKQ+CTLQUOTE:
-			str = "\"$(...)\"";
-			goto dostr;
 #if ENABLE_SH_MATH_SUPPORT
 		case CTLARI:
 			str = "$((";
@@ -5526,7 +5514,7 @@ ash_arith(const char *s)
 #define EXP_VARTILDE    0x4     /* expand tildes in an assignment */
 #define EXP_REDIR       0x8     /* file glob for a redirection (1 match only) */
 #define EXP_CASE        0x10    /* keeps quotes around for CASE pattern */
-#define EXP_RECORD      0x20    /* need to record arguments for ifs breakup */
+#define EXP_QPAT        0x20    /* pattern in quoted parameter expansion */
 #define EXP_VARTILDE2   0x40    /* expand tildes after colons only */
 #define EXP_WORD        0x80    /* expand word in parameter expansion */
 #define EXP_QUOTED      0x100   /* expand word in double quotes */
@@ -5535,12 +5523,11 @@ ash_arith(const char *s)
  */
 #define RMESCAPE_ALLOC  0x1     /* Allocate a new string */
 #define RMESCAPE_GLOB   0x2     /* Add backslashes for glob */
-#define RMESCAPE_QUOTED 0x4     /* Remove CTLESC unless in quotes */
 #define RMESCAPE_GROW   0x8     /* Grow strings instead of stalloc */
 #define RMESCAPE_HEAP   0x10    /* Malloc strings instead of stalloc */
 
 /* Add CTLESC when necessary. */
-#define QUOTES_ESC     (EXP_FULL | EXP_CASE | EXP_REDIR)
+#define QUOTES_ESC     (EXP_FULL | EXP_CASE | EXP_QPAT | EXP_REDIR)
 /* Do not skip NUL characters. */
 #define QUOTES_KEEPNUL EXP_TILDE
 
@@ -5641,13 +5628,11 @@ rmescapes(char *str, int flag)
 		}
 	}
 
-	inquotes = (flag & RMESCAPE_QUOTED) ^ RMESCAPE_QUOTED;
+	inquotes = 0;
 	globbing = flag & RMESCAPE_GLOB;
 	protect_against_glob = globbing;
 	while (*p) {
 		if ((unsigned char)*p == CTLQUOTEMARK) {
-// TODO: if no RMESCAPE_QUOTED in flags, inquotes never becomes 0
-// (alternates between RMESCAPE_QUOTED and ~RMESCAPE_QUOTED). Is it ok?
 // Note: both inquotes and protect_against_glob only affect whether
 // CTLESC,<ch> gets converted to <ch> or to \<ch>
 			inquotes = ~inquotes;
@@ -5655,16 +5640,15 @@ rmescapes(char *str, int flag)
 			protect_against_glob = globbing;
 			continue;
 		}
-		if (*p == '\\') {
-			/* naked back slash */
-			protect_against_glob = 0;
-			goto copy;
-		}
 		if ((unsigned char)*p == CTLESC) {
 			p++;
-			if (protect_against_glob && inquotes && *p != '/') {
+			if (protect_against_glob) {
 				*q++ = '\\';
 			}
+		} else if (*p == '\\' && !inquotes) {
+			/* naked back slash */
+			protect_against_glob = 0;
+			goto copy;
 		}
 		protect_against_glob = globbing;
  copy:
@@ -5685,13 +5669,9 @@ rmescapes(char *str, int flag)
  * Returns an stalloced string.
  */
 static char *
-preglob(const char *pattern, int quoted, int flag)
+preglob(const char *pattern, int flag)
 {
-	flag |= RMESCAPE_GLOB;
-	if (quoted) {
-		flag |= RMESCAPE_QUOTED;
-	}
-	return rmescapes((char *)pattern, flag);
+	return rmescapes((char *)pattern, flag | RMESCAPE_GLOB);
 }
 
 /*
@@ -5712,7 +5692,9 @@ memtodest(const char *p, size_t len, int syntax, int quotes)
 		if (c) {
 			int n = SIT(c, syntax);
 			if ((quotes & QUOTES_ESC) &&
-					(n == CCTL || n == CBACK))
+					((n == CCTL) ||
+					(((quotes & EXP_FULL) || syntax != BASESYNTAX) &&
+					n == CBACK)))
 				USTPUTC(CTLESC, q);
 		} else if (!(quotes & QUOTES_KEEPNUL))
 			continue;
@@ -5905,7 +5887,7 @@ evalbackcmd(union node *n, struct backcmd *result)
  * Expand stuff in backwards quotes.
  */
 static void
-expbackq(union node *cmd, int quoted, int quotes)
+expbackq(union node *cmd, int flag)
 {
 	struct backcmd in;
 	int i;
@@ -5913,7 +5895,7 @@ expbackq(union node *cmd, int quoted, int quotes)
 	char *p;
 	char *dest;
 	int startloc;
-	int syntax = quoted ? DQSYNTAX : BASESYNTAX;
+	int syntax = flag & EXP_QUOTED ? DQSYNTAX : BASESYNTAX;
 	struct stackmark smark;
 
 	INT_OFF;
@@ -5929,7 +5911,7 @@ expbackq(union node *cmd, int quoted, int quotes)
 	if (i == 0)
 		goto read;
 	for (;;) {
-		memtodest(p, i, syntax, quotes);
+		memtodest(p, i, syntax, flag & QUOTES_ESC);
  read:
 		if (in.fd < 0)
 			break;
@@ -5953,7 +5935,7 @@ expbackq(union node *cmd, int quoted, int quotes)
 		STUNPUTC(dest);
 	expdest = dest;
 
-	if (quoted == 0)
+	if (!(flag & EXP_QUOTED))
 		recordregion(startloc, dest - (char *)stackblock(), 0);
 	TRACE(("evalbackq: size:%d:'%.*s'\n",
 		(int)((dest - (char *)stackblock()) - startloc),
@@ -5967,11 +5949,10 @@ expbackq(union node *cmd, int quoted, int quotes)
  * evaluate, place result in (backed up) result, adjust string position.
  */
 static void
-expari(int quotes)
+expari(int flag)
 {
 	char *p, *start;
 	int begoff;
-	int flag;
 	int len;
 
 	/* ifsfree(); */
@@ -6009,16 +5990,14 @@ expari(int quotes)
 
 	removerecordregions(begoff);
 
-	flag = p[1];
-
 	expdest = p;
 
-	if (quotes)
-		rmescapes(p + 2, 0);
+	if (flag & QUOTES_ESC)
+		rmescapes(p + 1, 0);
 
-	len = cvtnum(ash_arith(p + 2));
+	len = cvtnum(ash_arith(p + 1));
 
-	if (flag != '"')
+	if (!(flag & EXP_QUOTED))
 		recordregion(begoff, begoff + len, 0);
 }
 #endif
@@ -6046,14 +6025,12 @@ argstr(char *p, int flags, struct strlist *var_str_list)
 		CTLESC,
 		CTLVAR,
 		CTLBACKQ,
-		CTLBACKQ | CTLQUOTE,
 #if ENABLE_SH_MATH_SUPPORT
 		CTLENDARI,
 #endif
 		'\0'
 	};
 	const char *reject = spclchars;
-	int quotes = flags & QUOTES_ESC;
 	int breakall = (flags & (EXP_WORD | EXP_QUOTED)) == EXP_WORD;
 	int inquotes;
 	size_t length;
@@ -6128,19 +6105,14 @@ argstr(char *p, int flags, struct strlist *var_str_list)
 		case CTLENDVAR: /* ??? */
 			goto breakloop;
 		case CTLQUOTEMARK:
+			inquotes ^= EXP_QUOTED;
 			/* "$@" syntax adherence hack */
-			if (!inquotes
-			 && memcmp(p, dolatstr, 4) == 0
-			 && (  p[4] == (char)CTLQUOTEMARK
-			    || (p[4] == (char)CTLENDVAR && p[5] == (char)CTLQUOTEMARK)
-			    )
-			) {
-				p = evalvar(p + 1, flags, /* var_str_list: */ NULL) + 1;
+			if (inquotes && !memcmp(p, dolatstr + 1, DOLATSTRLEN - 1)) {
+				p = evalvar(p + 1, flags | inquotes, /* var_str_list: */ NULL) + 1;
 				goto start;
 			}
-			inquotes = !inquotes;
  addquote:
-			if (quotes) {
+			if (flags & QUOTES_ESC) {
 				p--;
 				length++;
 				startloc++;
@@ -6149,22 +6121,30 @@ argstr(char *p, int flags, struct strlist *var_str_list)
 		case CTLESC:
 			startloc++;
 			length++;
+
+			/*
+			 * Quoted parameter expansion pattern: remove quote
+			 * unless inside inner quotes or we have a literal
+			 * backslash.
+			 */
+			if (((flags | inquotes) & (EXP_QPAT | EXP_QUOTED)) ==
+			    EXP_QPAT && *p != '\\')
+				break;
+
 			goto addquote;
 		case CTLVAR:
 			TRACE(("argstr: evalvar('%s')\n", p));
-			p = evalvar(p, flags, var_str_list);
+			p = evalvar(p, flags | inquotes, var_str_list);
 			TRACE(("argstr: evalvar:'%s'\n", (char *)stackblock()));
 			goto start;
 		case CTLBACKQ:
-			c = '\0';
-		case CTLBACKQ|CTLQUOTE:
-			expbackq(argbackq->n, c, quotes);
+			expbackq(argbackq->n, flags | inquotes);
 			argbackq = argbackq->next;
 			goto start;
 #if ENABLE_SH_MATH_SUPPORT
 		case CTLENDARI:
 			p--;
-			expari(quotes);
+			expari(flags | inquotes);
 			goto start;
 #endif
 		}
@@ -6296,13 +6276,13 @@ varunset(const char *end, const char *var, const char *umsg, int varflags)
 
 #if ENABLE_ASH_BASH_COMPAT
 static char *
-parse_sub_pattern(char *arg, int varflags)
+parse_sub_pattern(char *arg, int quoted)
 {
 	char *idx, *repl = NULL;
 	unsigned char c;
 
 	//char *org_arg = arg;
-	//bb_error_msg("arg:'%s' varflags:%x", arg, varflags);
+	//bb_error_msg("arg:'%s' quoted:%x", arg, quoted);
 	idx = arg;
 	while (1) {
 		c = *arg;
@@ -6318,7 +6298,7 @@ parse_sub_pattern(char *arg, int varflags)
 		*idx++ = c;
 		arg++;
 		/*
-		 * Example: v='ab\c'; echo ${v/\\b/_\\_\z_}
+		 * Example: v='a\bc'; echo ${v/\\b/_\\_\z_}
 		 * The result is a_\_z_c (not a\_\_z_c)!
 		 *
 		 * Enable debug prints in this function and you'll see:
@@ -6328,7 +6308,7 @@ parse_sub_pattern(char *arg, int varflags)
 		 * IOW: search pattern and replace string treat backslashes
 		 * differently! That is the reason why we check repl below:
 		 */
-		if (c == '\\' && *arg == '\\' && repl && !(varflags & VSQUOTE))
+		if (c == '\\' && *arg == '\\' && repl && !quoted)
 			arg++; /* skip both '\', not just first one */
 	}
 	*idx = c; /* NUL */
@@ -6340,9 +6320,10 @@ parse_sub_pattern(char *arg, int varflags)
 
 static const char *
 subevalvar(char *p, char *varname, int strloc, int subtype,
-		int startloc, int varflags, int quotes, struct strlist *var_str_list)
+		int startloc, int varflags, int flag, struct strlist *var_str_list)
 {
 	struct nodelist *saveargbackq = argbackq;
+	int quotes = flag & QUOTES_ESC;
 	char *startp;
 	char *loc;
 	char *rmesc, *rmescend;
@@ -6360,7 +6341,8 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 
 	herefd = -1;
 	argstr(p, EXP_TILDE | (subtype != VSASSIGN && subtype != VSQUESTION ?
-			EXP_CASE : 0), var_str_list);
+			(flag & (EXP_QUOTED | EXP_QPAT) ? EXP_QPAT : EXP_CASE) : 0),
+			var_str_list);
 	STPUTC('\0', expdest);
 	herefd = saveherefd;
 	argbackq = saveargbackq;
@@ -6471,7 +6453,7 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 	}
 	rmescend--;
 	str = (char *)stackblock() + strloc;
-	preglob(str, varflags & VSQUOTE, 0);
+	preglob(str, 0);
 
 #if ENABLE_ASH_BASH_COMPAT
 	workloc = expdest - (char *)stackblock();
@@ -6479,7 +6461,7 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 		char *idx, *end;
 
 		if (!repl) {
-			repl = parse_sub_pattern(str, varflags);
+			repl = parse_sub_pattern(str, flag & EXP_QUOTED);
 			//bb_error_msg("repl:'%s'", repl);
 			if (!repl)
 				repl = nullstr;
@@ -6618,7 +6600,7 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
 	int i;
 	ssize_t len = 0;
 	int sep;
-	int quoted = varflags & VSQUOTE;
+	int quoted = flags & EXP_QUOTED;
 	int subtype = varflags & VSTYPE;
 	int discard = subtype == VSPLUS || subtype == VSLENGTH;
 	int quotes = (discard ? 0 : (flags & QUOTES_ESC)) | QUOTES_KEEPNUL;
@@ -6758,7 +6740,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
 {
 	char varflags;
 	char subtype;
-	char quoted;
+	int quoted;
 	char easy;
 	char *var;
 	int patloc;
@@ -6767,7 +6749,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
 
 	varflags = (unsigned char) *p++;
 	subtype = varflags & VSTYPE;
-	quoted = varflags & VSQUOTE;
+	quoted = flags & EXP_QUOTED;
 	var = p;
 	easy = (!quoted || (*var == '@' && shellparam.nparam));
 	startloc = expdest - (char *)stackblock();
@@ -6788,7 +6770,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
 		if (varlen < 0) {
 			argstr(
 				p,
-				flags | EXP_TILDE | EXP_WORD | (quoted ? EXP_QUOTED : 0),
+				flags | EXP_TILDE | EXP_WORD,
 				var_str_list
 			);
 			goto end;
@@ -6802,7 +6784,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
 		if (varlen < 0) {
 			if (subevalvar(p, var, /* strloc: */ 0,
 					subtype, startloc, varflags,
-					/* quotes: */ 0,
+					/* quotes: */ flags & ~QUOTES_ESC,
 					var_str_list)
 			) {
 				varflags &= ~VSNUL;
@@ -6859,10 +6841,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
 		STPUTC('\0', expdest);
 		patloc = expdest - (char *)stackblock();
 		if (NULL == subevalvar(p, /* varname: */ NULL, patloc, subtype,
-				startloc, varflags,
-				/* quotes: */ flags & QUOTES_ESC,
-				var_str_list)
-		) {
+				startloc, varflags, flags, var_str_list)) {
 			int amount = expdest - (
 				(char *)stackblock() + patloc - 1
 			);
@@ -6881,7 +6860,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
 			unsigned char c = *p++;
 			if (c == CTLESC)
 				p++;
-			else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
+			else if (c == CTLBACKQ) {
 				if (varlen >= 0)
 					argbackq = argbackq->next;
 			} else if (c == CTLVAR) {
@@ -7217,7 +7196,7 @@ expandmeta(struct strlist *str /*, int flag*/)
 		savelastp = exparg.lastp;
 
 		INT_OFF;
-		p = preglob(str->text, 0, RMESCAPE_ALLOC | RMESCAPE_HEAP);
+		p = preglob(str->text, RMESCAPE_ALLOC | RMESCAPE_HEAP);
 		{
 			int i = strlen(str->text);
 			expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
@@ -7307,7 +7286,7 @@ static void
 expandhere(union node *arg, int fd)
 {
 	herefd = fd;
-	expandarg(arg, (struct arglist *)NULL, 0);
+	expandarg(arg, (struct arglist *)NULL, EXP_QUOTED);
 	full_write(fd, stackblock(), expdest - (char *)stackblock());
 }
 
@@ -7317,7 +7296,7 @@ expandhere(union node *arg, int fd)
 static int
 patmatch(char *pattern, const char *string)
 {
-	return pmatch(preglob(pattern, 0, 0), string);
+	return pmatch(preglob(pattern, 0), string);
 }
 
 /*
@@ -8570,7 +8549,7 @@ evalfor(union node *n, int flags)
 	arglist.list = NULL;
 	arglist.lastp = &arglist.list;
 	for (argp = n->nfor.args; argp; argp = argp->narg.next) {
-		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE | EXP_RECORD);
+		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 		/* XXX */
 		if (evalskip)
 			goto out;
@@ -11260,11 +11239,9 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
 				 && c != '$'
 				 && (c != '"' || eofmark != NULL)
 				) {
-					USTPUTC(CTLESC, out);
 					USTPUTC('\\', out);
 				}
-				if (SIT(c, SQSYNTAX) == CCTL)
-					USTPUTC(CTLESC, out);
+				USTPUTC(CTLESC, out);
 				USTPUTC(c, out);
 				quotef = 1;
 			}
@@ -11637,8 +11614,6 @@ parsesub: {
  do_pungetc:
 			pungetc();
 		}
-		if (dblquote || arinest)
-			flags |= VSQUOTE;
 		((unsigned char *)stackblock())[typeloc] = subtype | flags;
 		if (subtype != VSNORMAL) {
 			varnest++;
@@ -11792,10 +11767,7 @@ parsebackq: {
 	}
 	parsebackquote = savepbq;
 	exception_handler = savehandler;
-	if (arinest || dblquote)
-		USTPUTC(CTLBACKQ | CTLQUOTE, out);
-	else
-		USTPUTC(CTLBACKQ, out);
+	USTPUTC(CTLBACKQ, out);
 	if (oldstyle)
 		goto parsebackq_oldreturn;
 	goto parsebackq_newreturn;
@@ -11811,10 +11783,6 @@ parsearith: {
 		syntax = ARISYNTAX;
 	}
 	USTPUTC(CTLARI, out);
-	if (dblquote)
-		USTPUTC('"', out);
-	else
-		USTPUTC(' ', out);
 	goto parsearith_return;
 }
 #endif
@@ -12129,7 +12097,7 @@ expandstr(const char *ps)
 	n.narg.text = wordtext;
 	n.narg.backquote = backquotelist;
 
-	expandarg(&n, NULL, 0);
+	expandarg(&n, NULL, EXP_QUOTED);
 	return stackblock();
 }
 #endif
diff --git a/shell/ash_test/ash-vars/var-do-not-quote-backslashes-in-parameter-expansions-outside-quotes.right b/shell/ash_test/ash-vars/var-do-not-quote-backslashes-in-parameter-expansions-outside-quotes.right
new file mode 100644
index 000000000..030ebdeb6
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-do-not-quote-backslashes-in-parameter-expansions-outside-quotes.right
@@ -0,0 +1 @@
+/b/c/
diff --git a/shell/ash_test/ash-vars/var-do-not-quote-backslashes-in-parameter-expansions-outside-quotes.tests b/shell/ash_test/ash-vars/var-do-not-quote-backslashes-in-parameter-expansions-outside-quotes.tests
new file mode 100755
index 000000000..fb9371467
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-do-not-quote-backslashes-in-parameter-expansions-outside-quotes.tests
@@ -0,0 +1,3 @@
+a=/b/c/*
+b=\\
+echo ${a%$b*}
diff --git a/shell/ash_test/ash-vars/var-runtime-quote-detection.right b/shell/ash_test/ash-vars/var-runtime-quote-detection.right
new file mode 100644
index 000000000..b554d9e46
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-runtime-quote-detection.right
@@ -0,0 +1 @@
+<>
diff --git a/shell/ash_test/ash-vars/var-runtime-quote-detection.tests b/shell/ash_test/ash-vars/var-runtime-quote-detection.tests
new file mode 100755
index 000000000..e570631fd
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-runtime-quote-detection.tests
@@ -0,0 +1 @@
+foo=\\ echo "<${foo#[\\]}>"