hush: fix handling of by backslash-newline in $((arith)) and $(cmd)

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

diff --git a/shell/hush.c b/shell/hush.c
index e3dcf2c382f3a058bfec8bf6b97dcd0e26bb035d..177a794b5ae7863e88bdeb779ba26a21f56efc92 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2387,6 +2387,15 @@ static void o_addchr(o_string *o, int ch)
        o->data[o->length] = '\0';
 }
 
+#if 0
+/* Valid only if we know o_string is not empty */
+static void o_delchr(o_string *o)
+{
+       o->length--;
+       o->data[o->length] = '\0';
+}
+#endif
+
 static void o_addblock(o_string *o, const char *str, int len)
 {
        o_grow_by(o, len);
@@ -3900,6 +3909,23 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
        /* command remains "open", available for possible redirects */
 }
 
+static int i_peek_and_eat_bkslash_nl(struct in_str *input)
+{
+       for (;;) {
+               int ch, ch2;
+
+               ch = i_peek(input);
+               if (ch != '\\')
+                       return ch;
+               ch2 = i_peek2(input);
+               if (ch2 != '\n')
+                       return ch;
+               /* backslash+newline, skip it */
+               i_getch(input);
+               i_getch(input);
+       }
+}
+
 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_DOLLAR_OPS
 /* Subroutines for copying $(...) and `...` things */
 static int add_till_backquote(o_string *dest, struct in_str *input, int in_dquote);
@@ -4017,7 +4043,7 @@ static int add_till_closing_bracket(o_string *dest, struct in_str *input, unsign
                        if (!dbl)
                                break;
                        /* we look for closing )) of $((EXPR)) */
-                       if (i_peek(input) == end_ch) {
+                       if (i_peek_and_eat_bkslash_nl(input) == end_ch) {
                                i_getch(input); /* eat second ')' */
                                break;
                        }
@@ -4055,6 +4081,13 @@ static int add_till_closing_bracket(o_string *dest, struct in_str *input, unsign
                                syntax_error_unterm_ch(')');
                                return 0;
                        }
+#if 0
+                       if (ch == '\n') {
+                               /* "backslash+newline", ignore both */
+                               o_delchr(dest); /* undo insertion of '\' */
+                               continue;
+                       }
+#endif
                        o_addchr(dest, ch);
                        continue;
                }
@@ -4073,7 +4106,7 @@ static int parse_dollar(o_string *as_string,
                o_string *dest,
                struct in_str *input, unsigned char quote_mask)
 {
-       int ch = i_peek(input);  /* first character after the $ */
+       int ch = i_peek_and_eat_bkslash_nl(input);  /* first character after the $ */
 
        debug_printf_parse("parse_dollar entered: ch='%c'\n", ch);
        if (isalpha(ch)) {
@@ -4085,18 +4118,8 @@ static int parse_dollar(o_string *as_string,
                        debug_printf_parse(": '%c'\n", ch);
                        o_addchr(dest, ch | quote_mask);
                        quote_mask = 0;
- next_ch:
-                       ch = i_peek(input);
+                       ch = i_peek_and_eat_bkslash_nl(input);
                        if (!isalnum(ch) && ch != '_') {
-                               if (ch == '\\') {
-                                       /* If backslash+newline, skip it */
-                                       int ch2 = i_peek2(input);
-                                       if (ch2 == '\n') {
-                                               i_getch(input);
-                                               i_getch(input);
-                                               goto next_ch;
-                                       }
-                               }
                                /* End of variable name reached */
                                break;
                        }
@@ -4126,6 +4149,7 @@ static int parse_dollar(o_string *as_string,
                ch = i_getch(input); /* eat '{' */
                nommu_addchr(as_string, ch);
 
+               i_peek_and_eat_bkslash_nl(input);
                ch = i_getch(input); /* first char after '{' */
                /* It should be ${?}, or ${#var},
                 * or even ${?+subst} - operator acting on a special variable,
@@ -4232,7 +4256,7 @@ static int parse_dollar(o_string *as_string,
                ch = i_getch(input);
                nommu_addchr(as_string, ch);
 # if ENABLE_SH_MATH_SUPPORT
-               if (i_peek(input) == '(') {
+               if (i_peek_and_eat_bkslash_nl(input) == '(') {
                        ch = i_getch(input);
                        nommu_addchr(as_string, ch);
                        o_addchr(dest, SPECIAL_VAR_SYMBOL);
@@ -4269,7 +4293,7 @@ static int parse_dollar(o_string *as_string,
        case '_':
                ch = i_getch(input);
                nommu_addchr(as_string, ch);
-               ch = i_peek(input);
+               ch = i_peek_and_eat_bkslash_nl(input);
                if (isalnum(ch)) { /* it's $_name or $_123 */
                        ch = '_';
                        goto make_var;