implement most POSIX parameter expansions (~+500bytes)
This commit is contained in:
Mike Frysinger
parent
42ab86520e
commit
6379bb4fde
152
shell/hush.c
152
shell/hush.c
@ -43,12 +43,13 @@
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* Here Documents ( << word )
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* Functions
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* Tilde Expansion
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* fancy forms of Parameter Expansion: ${var:-val}
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* Parameter Expansion for substring processing ${var#word} ${var%word}
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*
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* Bash stuff maybe optional enable:
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* &> and >& redirection of stdout+stderr
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* Brace expansion
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* reserved words: [[ ]] function select
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* substrings ${var:1:5}
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*
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* Major bugs:
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* job handling woefully incomplete and buggy (improved --vda)
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@ -589,18 +590,20 @@ static const struct built_in_command bltins[] = {
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#if 1
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/* Normal */
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static void syntax(const char *msg)
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static void maybe_die(const char *notice, const char *msg)
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{
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#if ENABLE_HUSH_INTERACTIVE
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/* Was using fancy stuff:
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* (G.interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
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* but it SEGVs. ?! Oh well... explicit temp ptr works around that */
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void FAST_FUNC (*fp)(const char *s, ...);
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void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
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#if ENABLE_HUSH_INTERACTIVE
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fp = (G.interactive_fd ? bb_error_msg : bb_error_msg_and_die);
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fp(msg ? "%s: %s" : "syntax error", "syntax error", msg);
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#else
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bb_error_msg_and_die(msg ? "%s: %s" : "syntax error", "syntax error", msg);
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#endif
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fp(msg ? "%s: %s" : notice, notice, msg);
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}
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static void syntax(const char *msg)
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{
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maybe_die("syntax error", msg);
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}
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#else
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/* Debug */
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@ -920,7 +923,13 @@ static const char *lookup_param(const char *src)
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}
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/* str holds "NAME=VAL" and is expected to be malloced.
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* We take ownership of it. */
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* We take ownership of it.
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* flg_export is used by:
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* 0: do not export
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* 1: export
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* -1: if NAME is set, leave export status alone
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* if NAME is not set, do not export
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*/
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static int set_local_var(char *str, int flg_export)
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{
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struct variable *cur;
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@ -980,7 +989,7 @@ static int set_local_var(char *str, int flg_export)
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set_str_and_exp:
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cur->varstr = str;
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exp:
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if (flg_export)
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if (flg_export == 1)
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cur->flg_export = 1;
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if (cur->flg_export) {
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debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
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@ -1548,6 +1557,9 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
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val = utoa(G.last_return_code);
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break;
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case '#': /* argc */
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if (arg[1] != SPECIAL_VAR_SYMBOL)
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/* actually, it's a ${#var} */
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goto case_default;
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val = utoa(G.global_argc ? G.global_argc-1 : 0);
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break;
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case '*':
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@ -1615,20 +1627,79 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
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}
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#endif
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default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
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case_default: {
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bool exp_len = false, exp_null = false;
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char *var = arg, exp_save, exp_op, *exp_word;
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size_t exp_off = 0;
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*p = '\0';
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arg[0] = first_ch & 0x7f;
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if (isdigit(arg[0])) {
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i = xatoi_u(arg);
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/* prepare for expansions */
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if (var[0] == '#') {
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/* handle length expansion ${#var} */
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exp_len = true;
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++var;
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} else {
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/* maybe handle parameter expansion */
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exp_off = strcspn(var, ":-=+?");
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if (!var[exp_off])
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exp_off = 0;
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if (exp_off) {
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exp_save = var[exp_off];
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exp_null = exp_save == ':';
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exp_word = var + exp_off;
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if (exp_null) ++exp_word;
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exp_op = *exp_word++;
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var[exp_off] = '\0';
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}
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}
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/* lookup the variable in question */
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if (isdigit(var[0])) {
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i = xatoi_u(var);
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if (i < G.global_argc)
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val = G.global_argv[i];
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/* else val remains NULL: $N with too big N */
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} else
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val = lookup_param(arg);
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val = lookup_param(var);
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/* handle any expansions */
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if (exp_len) {
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debug_printf_expand("expand: length of '%s' = ", val);
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val = utoa(val ? strlen(val) : 0);
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debug_printf_expand("%s\n", val);
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} else if (exp_off) {
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/* we need to do an expansion */
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int exp_test = (!val || (exp_null && !val[0]));
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if (exp_op == '+')
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exp_test = !exp_test;
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debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
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exp_null ? "true" : "false", exp_test);
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if (exp_test) {
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if (exp_op == '?')
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maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
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else
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val = exp_word;
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if (exp_op == '=') {
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if (isdigit(var[0]) || var[0] == '#') {
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maybe_die(var, "special vars cannot assign in this way");
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val = NULL;
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} else {
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char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
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sprintf(new_var, "%s=%s", var, val);
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set_local_var(new_var, -1);
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}
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}
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}
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var[exp_off] = exp_save;
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}
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arg[0] = first_ch;
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#if ENABLE_HUSH_TICK
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store_val:
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#endif
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*p = SPECIAL_VAR_SYMBOL;
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if (!(first_ch & 0x80)) { /* unquoted $VAR */
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debug_printf_expand("unquoted '%s', output->o_quote:%d\n", val, output->o_quote);
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if (val) {
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@ -1643,9 +1714,13 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
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debug_printf_expand("quoted '%s', output->o_quote:%d\n", val, output->o_quote);
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}
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}
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}
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if (val) {
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o_addQstr(output, val, strlen(val));
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}
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/* Do the check to avoid writing to a const string */
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if (p && *p != SPECIAL_VAR_SYMBOL)
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*p = SPECIAL_VAR_SYMBOL;
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#if ENABLE_HUSH_TICK
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o_free(&subst_result);
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@ -3625,6 +3700,7 @@ static void add_till_closing_curly_brace(o_string *dest, struct in_str *input)
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/* Return code: 0 for OK, 1 for syntax error */
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static int handle_dollar(o_string *dest, struct in_str *input)
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{
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int expansion;
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int ch = i_peek(input); /* first character after the $ */
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unsigned char quote_mask = dest->o_quote ? 0x80 : 0;
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@ -3658,25 +3734,71 @@ static int handle_dollar(o_string *dest, struct in_str *input)
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case '*': /* args */
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case '@': /* args */
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goto make_one_char_var;
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case '{':
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case '{': {
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bool first_char;
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o_addchr(dest, SPECIAL_VAR_SYMBOL);
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i_getch(input);
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/* XXX maybe someone will try to escape the '}' */
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expansion = 0;
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first_char = true;
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while (1) {
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ch = i_getch(input);
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if (ch == '}')
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break;
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if (!isalnum(ch) && ch != '_') {
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if (ch == '#' && first_char)
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/* ${#var}: length of var contents */;
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else if (expansion < 2 && !isalnum(ch) && ch != '_') {
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/* handle parameter expansions
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* http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
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*/
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if (first_char)
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goto case_default;
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switch (ch) {
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case ':': /* null modifier */
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if (expansion == 0) {
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debug_printf_parse(": null modifier\n");
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++expansion;
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break;
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}
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goto case_default;
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#if 0 /* not implemented yet :( */
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case '#': /* remove prefix */
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case '%': /* remove suffix */
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if (expansion == 0) {
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debug_printf_parse(": remove suffix/prefix\n");
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expansion = 2;
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break;
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}
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goto case_default;
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#endif
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case '-': /* default value */
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case '=': /* assign default */
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case '+': /* alternative */
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case '?': /* error indicate */
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debug_printf_parse(": parameter expansion\n");
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expansion = 2;
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break;
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default:
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case_default:
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syntax("unterminated ${name}");
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debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
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return 1;
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}
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}
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debug_printf_parse(": '%c'\n", ch);
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o_addchr(dest, ch | quote_mask);
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quote_mask = 0;
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first_char = false;
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}
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o_addchr(dest, SPECIAL_VAR_SYMBOL);
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break;
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}
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#if ENABLE_HUSH_TICK
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case '(': {
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//int pos = dest->length;
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