Function safe_arg

options.c:2539–2594

* Do backslash quoting of any weird chars in "arg", append the resulting * string to the end of the "opt" (which gets a "=" appended if it is not * an empty or NULL string), and return the (perhaps malloced) result. * If opt is NULL, arg is considered a filename arg that allows wildcards. * If it is "" or any other value, it is considered an option. **/

 * If it is "" or any other value, it is considered an option.
 **/
char *safe_arg(const char *opt, const char *arg)
{
#define SHELL_CHARS "!#$&;|<>(){}\"'` \t\\"
#define WILD_CHARS  "*?[]" /* We don't allow remote brace expansion */
	BOOL is_filename_arg = !opt;
	char *escapes = is_filename_arg ? SHELL_CHARS : WILD_CHARS SHELL_CHARS;
	BOOL escape_leading_dash = is_filename_arg && *arg == '-';
	BOOL escape_leading_tilde = 0;
	int len1 = opt && *opt ? strlen(opt) + 1 : 0;
	int len2 = strlen(arg);
	int extras = escape_leading_dash ? 2 : 0;
	char *ret;
	if (!protect_args && old_style_args < 2 && (!old_style_args || (!is_filename_arg && opt != SPLIT_ARG_WHEN_OLD))) {
		const char *f;
		if (*arg == '~' && is_filename_arg && !am_sender && !trust_sender_args
		 && ((relative_paths && !strstr(arg, "/./"))
		  || !strchr(arg, '/'))) {
			extras++;
			escape_leading_tilde = 1;
		}
		for (f = arg; *f; f++) {
			if (strchr(escapes, *f))
				extras++;
		}
	}
	if (!len1 && !extras)
		return (char*)arg;
	ret = new_array(char, len1 + len2 + extras + 1);
	if (len1) {
		memcpy(ret, opt, len1-1);
		ret[len1-1] = '=';
	}
	if (escape_leading_dash) {
		ret[len1++] = '.';
		ret[len1++] = '/';
		extras -= 2;
	}
	if (!extras)
		memcpy(ret + len1, arg, len2);
	else {
		const char *f = arg;
		char *t = ret + len1;
		if (escape_leading_tilde)
			*t++ = '\\';
		while (*f) {
			if (*f == '\\') {
				if (!is_filename_arg || !strchr(WILD_CHARS, f[1]))
					*t++ = '\\';
			} else if (strchr(escapes, *f))
				*t++ = '\\';
			*t++ = *f++;
		}
	}
	ret[len1+len2+extras] = '\0';
	return ret;
}