hush: implement $'str' bashism

function                                             old     new   delta
parse_dollar_squote                                    -     441    +441
encode_then_expand_vararg                            359     380     +21
parse_stream                                        2252    2271     +19
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/0 up/down: 481/0)             Total: 481 bytes

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

7 files changed, 138 insertions, 1 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 1aa0a400d..af6a9a73e 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -384,6 +384,7 @@
 #define BASH_PATTERN_SUBST ENABLE_HUSH_BASH_COMPAT
 #define BASH_SUBSTR        ENABLE_HUSH_BASH_COMPAT
 #define BASH_SOURCE        ENABLE_HUSH_BASH_COMPAT
+#define BASH_DOLLAR_SQUOTE ENABLE_HUSH_BASH_COMPAT
 #define BASH_HOSTNAME_VAR  ENABLE_HUSH_BASH_COMPAT
 #define BASH_EPOCH_VARS    ENABLE_HUSH_BASH_COMPAT
 #define BASH_TEST2         (ENABLE_HUSH_BASH_COMPAT && ENABLE_HUSH_TEST)
@@ -4919,6 +4920,100 @@ static int add_till_closing_bracket(o_string *dest, struct in_str *input, unsign
 }
 #endif /* ENABLE_HUSH_TICK || ENABLE_FEATURE_SH_MATH || ENABLE_HUSH_DOLLAR_OPS */
 
+#if BASH_DOLLAR_SQUOTE
+/* Return code: 1 for "found and parsed", 0 for "seen something else" */
+#if BB_MMU
+#define parse_dollar_squote(as_string, dest, input) \
+        parse_dollar_squote(dest, input)
+#define as_string NULL
+#endif
+static int parse_dollar_squote(o_string *as_string, o_string *dest, struct in_str *input)
+{
+        int start;
+        int ch = i_peek_and_eat_bkslash_nl(input);  /* first character after the $ */
+        debug_printf_parse("parse_dollar_squote entered: ch='%c'\n", ch);
+        if (ch != '\'')
+                return 0;
+
+        dest->has_quoted_part = 1;
+        start = dest->length;
+
+        ch = i_getch(input); /* eat ' */
+        nommu_addchr(as_string, ch);
+        while (1) {
+                ch = i_getch(input);
+                nommu_addchr(as_string, ch);
+                if (ch == EOF) {
+                        syntax_error_unterm_ch('\'');
+                        return 0;
+                }
+                if (ch == '\'')
+                        break;
+                if (ch == SPECIAL_VAR_SYMBOL) {
+                        /* Convert raw ^C to corresponding special variable reference */
+                        o_addchr(dest, SPECIAL_VAR_SYMBOL);
+                        o_addchr(dest, SPECIAL_VAR_QUOTED_SVS);
+                        /* will addchr() another SPECIAL_VAR_SYMBOL (see after the if() block) */
+                } else if (ch == '\\') {
+                        static const char C_escapes[] ALIGN1 = "nrbtfav""x\\01234567";
+
+                        ch = i_getch(input);
+                        nommu_addchr(as_string, ch);
+                        if (strchr(C_escapes, ch)) {
+                                char buf[4];
+                                char *p = buf;
+                                int cnt = 2;
+
+                                buf[0] = ch;
+                                if ((unsigned char)(ch - '0') <= 7) { /* \ooo */
+                                        do {
+                                                ch = i_peek(input);
+                                                if ((unsigned char)(ch - '0') > 7)
+                                                        break;
+                                                *++p = ch = i_getch(input);
+                                                nommu_addchr(as_string, ch);
+                                        } while (--cnt != 0);
+                                } else if (ch == 'x') { /* \xHH */
+                                        do {
+                                                ch = i_peek(input);
+                                                if (!isxdigit(ch))
+                                                        break;
+                                                *++p = ch = i_getch(input);
+                                                nommu_addchr(as_string, ch);
+                                        } while (--cnt != 0);
+                                        if (cnt == 2) { /* \x but next char is "bad" */
+                                                ch = 'x';
+                                                goto unrecognized;
+                                        }
+                                } /* else simple seq like \\ or \t */
+                                *++p = '\0';
+                                p = buf;
+                                ch = bb_process_escape_sequence((void*)&p);
+                                //bb_error_msg("buf:'%s' ch:%x", buf, ch);
+                                if (ch == '\0')
+                                        continue; /* bash compat: $'...\0...' emits nothing */
+                        } else { /* unrecognized "\z": encode both chars unless ' or " */
+                                if (ch != '\'' && ch != '"') {
+ unrecognized:
+                                        o_addqchr(dest, '\\');
+                                }
+                        }
+                } /* if (\...) */
+                o_addqchr(dest, ch);
+        }
+
+        if (dest->length == start) {
+                /* $'', $'\0', $'\000\x00' and the like */
+                o_addchr(dest, SPECIAL_VAR_SYMBOL);
+                o_addchr(dest, SPECIAL_VAR_SYMBOL);
+        }
+
+        return 1;
+}
+#else
+# #define parse_dollar_squote(as_string, dest, input) 0
+#endif /* BASH_DOLLAR_SQUOTE */
+
 /* Return code: 0 for OK, 1 for syntax error */
 #if BB_MMU
 #define parse_dollar(as_string, dest, input, quote_mask) \
@@ -4931,7 +5026,7 @@ static int parse_dollar(o_string *as_string,
 {
         int ch = i_peek_and_eat_bkslash_nl(input);  /* first character after the $ */
 
-        debug_printf_parse("parse_dollar entered: ch='%c'\n", ch);
+        debug_printf_parse("parse_dollar entered: ch='%c' quote_mask:0x%x\n", ch, quote_mask);
         if (isalpha(ch)) {
  make_var:
                 ch = i_getch(input);
@@ -5247,6 +5342,8 @@ static int encode_string(o_string *as_string,
                 goto again;
         }
         if (ch == '$') {
+                //if (parse_dollar_squote(as_string, dest, input))
+                //      goto again;
                 if (!parse_dollar(as_string, dest, input, /*quote_mask:*/ 0x80)) {
                         debug_printf_parse("encode_string return 0: "
                                         "parse_dollar returned 0 (error)\n");
@@ -5723,6 +5820,8 @@ static struct pipe *parse_stream(char **pstring,
                         o_addchr(&ctx.word, ch);
                         continue; /* get next char */
                 case '$':
+                        if (parse_dollar_squote(&ctx.as_string, &ctx.word, input))
+                                continue; /* get next char */
                         if (!parse_dollar(&ctx.as_string, &ctx.word, input, /*quote_mask:*/ 0)) {
                                 debug_printf_parse("parse_stream parse error: "
                                         "parse_dollar returned 0 (error)\n");
@@ -6166,6 +6265,8 @@ static char *encode_then_expand_vararg(const char *str, int handle_squotes, int
                         continue;
                 }
                 if (ch == '$') {
+                        if (parse_dollar_squote(NULL, &dest, &input))
+                                continue;
                         if (!parse_dollar(NULL, &dest, &input, /*quote_mask:*/ 0x80)) {
                                 debug_printf_parse("%s: error: parse_dollar returned 0 (error)\n", __func__);
                                 goto ret;
diff --git a/shell/hush_test/hush-quoting/dollar_squote_bash1.right b/shell/hush_test/hush-quoting/dollar_squote_bash1.right
new file mode 100644
index 000000000..9f4e25efa
--- /dev/null
+++ b/shell/hush_test/hush-quoting/dollar_squote_bash1.right
@@ -0,0 +1,10 @@
+a       b
+$'a\tb'
+a
+b c
+def
+a'b c"d e\f
+a3b c3b e33f
+a\80b c08b
+a3b c30b
+x       y
diff --git a/shell/hush_test/hush-quoting/dollar_squote_bash1.tests b/shell/hush_test/hush-quoting/dollar_squote_bash1.tests
new file mode 100755
index 000000000..6fc411b93
--- /dev/null
+++ b/shell/hush_test/hush-quoting/dollar_squote_bash1.tests
@@ -0,0 +1,8 @@
+echo $'a\tb'
+echo "$'a\tb'"
+echo $'a\nb' $'c\nd''ef'
+echo $'a\'b' $'c\"d' $'e\\f'
+echo $'a\63b' $'c\063b' $'e\0633f'
+echo $'a\80b' $'c\608b'
+echo $'a\x33b' $'c\x330b'
+echo $'x\x9y'
diff --git a/shell/hush_test/hush-quoting/dollar_squote_bash2.right b/shell/hush_test/hush-quoting/dollar_squote_bash2.right
new file mode 100644
index 000000000..f7a1731dd
--- /dev/null
+++ b/shell/hush_test/hush-quoting/dollar_squote_bash2.right
@@ -0,0 +1,6 @@
+strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+80:\�
+81:\�
+82:\�
+Done:0
diff --git a/shell/hush_test/hush-quoting/dollar_squote_bash2.tests b/shell/hush_test/hush-quoting/dollar_squote_bash2.tests
new file mode 100755
index 000000000..449772813
--- /dev/null
+++ b/shell/hush_test/hush-quoting/dollar_squote_bash2.tests
@@ -0,0 +1,10 @@
+# Embedded NULs
+echo $'str\x00'strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+echo $'str\000'strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+
+# The chars after '\' are hex 0x80,81,82...
+echo 80:$'\�'
+echo 81:$'\�'
+echo 82:$'\�'
+
+echo Done:$?
diff --git a/shell/hush_test/hush-vars/var_bash7.right b/shell/hush_test/hush-vars/var_bash7.right
new file mode 100644
index 000000000..223b7836f
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_bash7.right
@@ -0,0 +1 @@
+B
diff --git a/shell/hush_test/hush-vars/var_bash7.tests b/shell/hush_test/hush-vars/var_bash7.tests
new file mode 100755
index 000000000..c4ce03f7f
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_bash7.tests
@@ -0,0 +1 @@
+x=AB; echo "${x#$'\x41'}"