conditionally add wordexp, in this case ripped from glibc.

I hate to add this stuff, but it is specified by SuSv3...

3 files changed, 2287 insertions, 1 deletions

diff --git a/libc/misc/Makefile b/libc/misc/Makefile
index 037e2154d..24a963516 100644
--- a/libc/misc/Makefile
+++ b/libc/misc/Makefile
@@ -27,10 +27,13 @@ include $(TOPDIR)Rules.mak
 
 DIRS = assert ctype dirent file fnmatch glob internals \
        mntent syslog time utmp sysvipc statfs \
-       error ttyent gnu search intl locale 
+       error ttyent gnu search intl locale
 ifeq ($(strip $(UCLIBC_HAS_REGEX)),y)
 DIRS += regex
 endif
+ifeq ($(strip $(UCLIBC_HAS_WORDEXP)),y)
+DIRS += wordexp
+endif
 ifeq ($(strip $(UCLIBC_HAS_THREADS)),y)
 DIRS += pthread
 endif
diff --git a/libc/misc/wordexp/Makefile b/libc/misc/wordexp/Makefile
new file mode 100644
index 000000000..edfd819d5
--- /dev/null
+++ b/libc/misc/wordexp/Makefile
@@ -0,0 +1,39 @@
+# Makefile for uClibc
+#
+# Copyright (C) 2003 Erik Andersen <andersen@uclibc.org>
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU Library General Public License as published by the Free
+# Software Foundation; either version 2 of the License, or (at your option) any
+# later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Library General Public License
+# along with this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+TOPDIR=../../../
+include $(TOPDIR)Rules.mak
+
+CSRC=wordexp.c
+COBJS=$(patsubst %.c,%.o, $(CSRC))
+OBJS=$(COBJS)
+
+all: $(OBJS) $(LIBC)
+
+$(LIBC): ar-target
+
+ar-target: $(OBJS)
+	$(AR) $(ARFLAGS) $(LIBC) $(OBJS)
+
+$(COBJS): %.o : %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+	$(STRIPTOOL) -x -R .note -R .comment $*.o
+
+clean:
+	rm -f *.[oa] *~ core
+
diff --git a/libc/misc/wordexp/wordexp.c b/libc/misc/wordexp/wordexp.c
new file mode 100644
index 000000000..628b8f3fe
--- /dev/null
+++ b/libc/misc/wordexp/wordexp.c
@@ -0,0 +1,2244 @@
+/* vi: set sw=4 ts=4: */
+/* POSIX.2 wordexp implementation.
+   Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Tim Waugh <tim@cyberelk.demon.co.uk>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#define _GNU_SOURCE
+#include <sys/cdefs.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <pwd.h>
+#include <errno.h>
+#include <assert.h>
+#include <fnmatch.h>
+#include <glob.h>
+#include <wordexp.h>
+
+#define __WORDEXP_FULL
+//#undef __WORDEXP_FULL
+
+/*
+ * This is a recursive-descent-style word expansion routine.
+ */
+
+/* These variables are defined and initialized in the startup code.  */
+//extern int __libc_argc;
+//extern char **__libc_argv;
+
+/* FIXME!!!! */
+int __libc_argc;
+char **__libc_argv;
+
+/* Some forward declarations */
+static int parse_dollars(char **word, size_t * word_length,
+						 size_t * max_length, const char *words,
+						 size_t * offset, int flags, wordexp_t * pwordexp,
+						 const char *ifs, const char *ifs_white,
+						 int quoted);
+static int parse_backtick(char **word, size_t * word_length,
+						  size_t * max_length, const char *words,
+						  size_t * offset, int flags, wordexp_t * pwordexp,
+						  const char *ifs, const char *ifs_white);
+static int parse_dquote(char **word, size_t * word_length,
+						size_t * max_length, const char *words,
+						size_t * offset, int flags, wordexp_t * pwordexp,
+						const char *ifs, const char *ifs_white);
+
+
+
+/* The w_*() functions manipulate word lists. */
+#define W_CHUNK	(100)
+
+/* Result of w_newword will be ignored if it's the last word. */
+static inline char *w_newword(size_t * actlen, size_t * maxlen)
+{
+	*actlen = *maxlen = 0;
+	return NULL;
+}
+
+/* Add a character to the buffer, allocating room for it if needed.  */
+static inline char *w_addchar(char *buffer, size_t * actlen,
+							  size_t * maxlen, char ch)
+	 /* (lengths exclude trailing zero) */
+{
+
+	if (*actlen == *maxlen) {
+		char *old_buffer = buffer;
+		assert(buffer == NULL || *maxlen != 0);
+		*maxlen += W_CHUNK;
+		buffer = realloc(buffer, 1 + *maxlen);
+		if (buffer == NULL)
+			free(old_buffer);
+	}
+
+	if (buffer != NULL) {
+		buffer[*actlen] = ch;
+		buffer[++(*actlen)] = '\0';
+	}
+
+	return buffer;
+}
+
+#define MAX( a, b ) ( ( ( a ) > ( b ) ) ? ( a ) : ( b ) )
+static char *w_addmem(char *buffer, size_t * actlen, size_t * maxlen,
+					  const char *str, size_t len)
+{
+	/* Add a string to the buffer, allocating room for it if needed.
+	 */
+	if (*actlen + len > *maxlen) {
+		char *old_buffer = buffer;
+		assert(buffer == NULL || *maxlen != 0);
+		*maxlen += MAX(2 * len, W_CHUNK);
+		buffer = realloc(old_buffer, 1 + *maxlen);
+		if (buffer == NULL)
+			free(old_buffer);
+	}
+
+	if (buffer != NULL) {
+		*((char *) mempcpy(&buffer[*actlen], str, len)) = '\0';
+		*actlen += len;
+	}
+	return buffer;
+}
+
+/* Add a string to the buffer, allocating room for it if needed.  */
+static char *w_addstr(char *buffer, size_t * actlen, size_t * maxlen,
+					  const char *str)
+	 /* (lengths exclude trailing zero) */
+{
+	size_t len;
+	assert(str != NULL);		/* w_addstr only called from this file */
+	len = strlen(str);
+
+	return w_addmem(buffer, actlen, maxlen, str, len);
+}
+
+/* Add a word to the wordlist */
+static int w_addword(wordexp_t * pwordexp, char *word)
+{
+	size_t num_p;
+	char **new_wordv;
+
+	/* Internally, NULL acts like "".  Convert NULLs to "" before
+	 * the caller sees them.
+	 */
+	if (word == NULL) {
+		word = strdup("");
+		if (word == NULL)
+			goto no_space;
+	}
+
+	num_p = 2 + pwordexp->we_wordc + pwordexp->we_offs;
+	new_wordv = realloc(pwordexp->we_wordv, sizeof(char *) * num_p);
+	if (new_wordv != NULL) {
+		pwordexp->we_wordv = new_wordv;
+		pwordexp->we_wordv[pwordexp->we_offs + pwordexp->we_wordc++] = word;
+		pwordexp->we_wordv[pwordexp->we_offs + pwordexp->we_wordc] = NULL;
+		return 0;
+	}
+
+  no_space:
+	return WRDE_NOSPACE;
+}
+
+/* The parse_*() functions should leave *offset being the offset in 'words'
+ * to the last character processed.
+ */
+static int
+parse_backslash(char **word, size_t * word_length, size_t * max_length,
+				const char *words, size_t * offset)
+{
+	/* We are poised _at_ a backslash, not in quotes */
+
+	switch (words[1 + *offset]) {
+	case 0:
+		/* Backslash is last character of input words */
+		return WRDE_SYNTAX;
+
+	case '\n':
+		++(*offset);
+		break;
+
+	default:
+		*word = w_addchar(*word, word_length, max_length, words[1 + *offset]);
+		if (*word == NULL)
+			return WRDE_NOSPACE;
+
+		++(*offset);
+		break;
+	}
+
+	return 0;
+}
+
+static int
+parse_qtd_backslash(char **word, size_t * word_length, size_t * max_length,
+					const char *words, size_t * offset)
+{
+	/* We are poised _at_ a backslash, inside quotes */
+
+	switch (words[1 + *offset]) {
+	case 0:
+		/* Backslash is last character of input words */
+		return WRDE_SYNTAX;
+
+	case '\n':
+		++(*offset);
+		break;
+
+	case '$':
+	case '`':
+	case '"':
+	case '\\':
+		*word =
+			w_addchar(*word, word_length, max_length, words[1 + *offset]);
+		if (*word == NULL)
+			return WRDE_NOSPACE;
+
+		++(*offset);
+		break;
+
+	default:
+		*word = w_addchar(*word, word_length, max_length, words[*offset]);
+		if (*word != NULL)
+			*word =
+				w_addchar(*word, word_length, max_length,
+						  words[1 + *offset]);
+
+		if (*word == NULL)
+			return WRDE_NOSPACE;
+
+		++(*offset);
+		break;
+	}
+
+	return 0;
+}
+
+static int
+parse_tilde(char **word, size_t * word_length, size_t * max_length,
+			const char *words, size_t * offset, size_t wordc)
+{
+	/* We are poised _at_ a tilde */
+	size_t i;
+
+	if (*word_length != 0) {
+		if (!((*word)[*word_length - 1] == '=' && wordc == 0)) {
+			if (!((*word)[*word_length - 1] == ':'
+				  && strchr(*word, '=') && wordc == 0)) {
+				*word = w_addchar(*word, word_length, max_length, '~');
+				return *word ? 0 : WRDE_NOSPACE;
+			}
+		}
+	}
+
+	for (i = 1 + *offset; words[i]; i++) {
+		if (words[i] == ':' || words[i] == '/' || words[i] == ' ' ||
+			words[i] == '\t' || words[i] == 0)
+			break;
+
+		if (words[i] == '\\') {
+			*word = w_addchar(*word, word_length, max_length, '~');
+			return *word ? 0 : WRDE_NOSPACE;
+		}
+	}
+
+	if (i == 1 + *offset) {
+		/* Tilde appears on its own */
+		uid_t uid;
+		struct passwd pwd, *tpwd;
+		int buflen = 1000;
+		char *home;
+		char *buffer;
+		int result;
+
+		/* POSIX.2 says ~ expands to $HOME and if HOME is unset the
+		   results are unspecified.  We do a lookup on the uid if
+		   HOME is unset. */
+
+		home = getenv("HOME");
+		if (home != NULL) {
+			*word = w_addstr(*word, word_length, max_length, home);
+			if (*word == NULL)
+				return WRDE_NOSPACE;
+		} else {
+			uid = getuid();
+			buffer = alloca(buflen);
+
+			while ((result = getpwuid_r(uid, &pwd, buffer, buflen, &tpwd)) 
+					!= 0 && errno == ERANGE) 
+			{
+				buflen += 1000;
+				buffer = alloca(buflen);
+			}
+
+			if (result == 0 && tpwd != NULL && pwd.pw_dir != NULL) {
+				*word = w_addstr(*word, word_length, max_length, pwd.pw_dir);
+				if (*word == NULL)
+					return WRDE_NOSPACE;
+			} else {
+				*word = w_addchar(*word, word_length, max_length, '~');
+				if (*word == NULL)
+					return WRDE_NOSPACE;
+			}
+		}
+	} else {
+		/* Look up user name in database to get home directory */
+		char *user = strndup(&words[1 + *offset], i - (1 + *offset));
+		struct passwd pwd, *tpwd;
+		int buflen = 1000;
+		char *buffer = alloca(buflen);
+		int result;
+
+		while ((result = getpwnam_r(user, &pwd, buffer, buflen, &tpwd)) != 0
+			   && errno == ERANGE) {
+			buflen += 1000;
+			buffer = alloca(buflen);
+		}
+
+		if (result == 0 && tpwd != NULL && pwd.pw_dir)
+			*word = w_addstr(*word, word_length, max_length, pwd.pw_dir);
+		else {
+			/* (invalid login name) */
+			*word = w_addchar(*word, word_length, max_length, '~');
+			if (*word != NULL)
+				*word = w_addstr(*word, word_length, max_length, user);
+		}
+
+		*offset = i - 1;
+	}
+	return *word ? 0 : WRDE_NOSPACE;
+}
+
+
+static int
+do_parse_glob(const char *glob_word, char **word, size_t * word_length,
+			  size_t * max_length, wordexp_t * pwordexp, const char *ifs,
+			  const char *ifs_white)
+{
+	int error;
+	int match;
+	glob_t globbuf;
+
+	error = glob(glob_word, GLOB_NOCHECK, NULL, &globbuf);
+
+	if (error != 0) {
+		/* We can only run into memory problems.  */
+		assert(error == GLOB_NOSPACE);
+		return WRDE_NOSPACE;
+	}
+
+	if (ifs && !*ifs) {
+		/* No field splitting allowed. */
+		assert(globbuf.gl_pathv[0] != NULL);
+		*word = w_addstr(*word, word_length, max_length, globbuf.gl_pathv[0]);
+		for (match = 1; match < globbuf.gl_pathc && *word != NULL; ++match) {
+			*word = w_addchar(*word, word_length, max_length, ' ');
+			if (*word != NULL)
+				*word = w_addstr(*word, word_length, max_length,
+								 globbuf.gl_pathv[match]);
+		}
+
+		globfree(&globbuf);
+		return *word ? 0 : WRDE_NOSPACE;
+	}
+
+	assert(ifs == NULL || *ifs != '\0');
+	if (*word != NULL) {
+		free(*word);
+		*word = w_newword(word_length, max_length);
+	}
+
+	for (match = 0; match < globbuf.gl_pathc; ++match) {
+		char *matching_word = strdup(globbuf.gl_pathv[match]);
+
+		if (matching_word == NULL || w_addword(pwordexp, matching_word)) {
+			globfree(&globbuf);
+			return WRDE_NOSPACE;
+		}
+	}
+
+	globfree(&globbuf);
+	return 0;
+}
+
+static int
+parse_glob(char **word, size_t * word_length, size_t * max_length,
+		   const char *words, size_t * offset, int flags,
+		   wordexp_t * pwordexp, const char *ifs, const char *ifs_white)
+{
+	/* We are poised just after a '*', a '[' or a '?'. */
+	int error = WRDE_NOSPACE;
+	int quoted = 0;				/* 1 if singly-quoted, 2 if doubly */
+	int i;
+	wordexp_t glob_list;		/* List of words to glob */
+
+	glob_list.we_wordc = 0;
+	glob_list.we_wordv = NULL;
+	glob_list.we_offs = 0;
+	for (; words[*offset] != '\0'; ++*offset) {
+		if ((ifs && strchr(ifs, words[*offset])) ||
+			(!ifs && strchr(" \t\n", words[*offset])))
+			/* Reached IFS */
+			break;
+
+		/* Sort out quoting */
+		if (words[*offset] == '\'') {
+			if (quoted == 0) {
+				quoted = 1;
+				continue;
+			} else if (quoted == 1) {
+				quoted = 0;
+				continue;
+			}
+		} else if (words[*offset] == '"') {
+			if (quoted == 0) {
+				quoted = 2;
+				continue;
+			} else if (quoted == 2) {
+				quoted = 0;
+				continue;
+			}
+		}
+
+		/* Sort out other special characters */
+		if (quoted != 1 && words[*offset] == '$') {
+			error = parse_dollars(word, word_length, max_length, words,
+								  offset, flags, &glob_list, ifs,
+								  ifs_white, quoted == 2);
+			if (error)
+				goto tidy_up;
+
+			continue;
+		} else if (words[*offset] == '\\') {
+			if (quoted)
+				error = parse_qtd_backslash(word, word_length, max_length,
+											words, offset);
+			else
+				error = parse_backslash(word, word_length, max_length,
+										words, offset);
+
+			if (error)
+				goto tidy_up;
+
+			continue;
+		}
+
+		*word = w_addchar(*word, word_length, max_length, words[*offset]);
+		if (*word == NULL)
+			goto tidy_up;
+	}
+
+	/* Don't forget to re-parse the character we stopped at. */
+	--*offset;
+
+	/* Glob the words */
+	error = w_addword(&glob_list, *word);
+	*word = w_newword(word_length, max_length);
+	for (i = 0; error == 0 && i < glob_list.we_wordc; i++)
+		error = do_parse_glob(glob_list.we_wordv[i], word, word_length,
+							  max_length, pwordexp, ifs, ifs_white);
+
+	/* Now tidy up */
+  tidy_up:
+	wordfree(&glob_list);
+	return error;
+}
+
+static int
+parse_squote(char **word, size_t * word_length, size_t * max_length,
+			 const char *words, size_t * offset)
+{
+	/* We are poised just after a single quote */
+	for (; words[*offset]; ++(*offset)) {
+		if (words[*offset] != '\'') {
+			*word = w_addchar(*word, word_length, max_length, words[*offset]);
+			if (*word == NULL)
+				return WRDE_NOSPACE;
+		} else
+			return 0;
+	}
+
+	/* Unterminated string */
+	return WRDE_SYNTAX;
+}
+
+#ifdef __WORDEXP_FULL
+static int eval_expr(char *expr, long int *result);
+
+static char *_itoa(unsigned long long int value, char *buflim)
+{
+	sprintf(buflim, "%llu", value);
+	return buflim;
+}
+
+/* Functions to evaluate an arithmetic expression */
+static int eval_expr_val(char **expr, long int *result)
+{
+	int sgn = +1;
+	char *digit;
+
+	/* Skip white space */
+	for (digit = *expr; digit && *digit && isspace(*digit); ++digit);
+
+	switch (*digit) {
+	case '(':
+
+		/* Scan for closing paren */
+		for (++digit; **expr && **expr != ')'; ++(*expr));
+
+		/* Is there one? */
+		if (!**expr)
+			return WRDE_SYNTAX;
+
+		*(*expr)++ = 0;
+
+		if (eval_expr(digit, result))
+			return WRDE_SYNTAX;
+
+		return 0;
+
+	case '+':					/* Positive value */
+		++digit;
+		break;
+
+	case '-':					/* Negative value */
+		++digit;
+		sgn = -1;
+		break;
+
+	default:
+		if (!isdigit(*digit))
+			return WRDE_SYNTAX;
+	}
+
+	*result = 0;
+	for (; *digit && isdigit(*digit); ++digit)
+		*result = (*result * 10) + (*digit - '0');
+
+	*expr = digit;
+	*result *= sgn;
+	return 0;
+}
+
+static int eval_expr_multdiv(char **expr, long int *result)
+{
+	long int arg;
+
+	/* Read a Value */
+	if (eval_expr_val(expr, result) != 0)
+		return WRDE_SYNTAX;
+
+	while (**expr) {
+		/* Skip white space */
+		for (; *expr && **expr && isspace(**expr); ++(*expr));
+
+		if (**expr == '*') {
+			++(*expr);
+			if (eval_expr_val(expr, &arg) != 0)
+				return WRDE_SYNTAX;
+
+			*result *= arg;
+		} else if (**expr == '/') {
+			++(*expr);
+			if (eval_expr_val(expr, &arg) != 0)
+				return WRDE_SYNTAX;
+
+			*result /= arg;
+		} else
+			break;
+	}
+
+	return 0;
+}
+
+static int eval_expr(char *expr, long int *result)
+{
+	long int arg;
+
+	/* Read a Multdiv */
+	if (eval_expr_multdiv(&expr, result) != 0)
+		return WRDE_SYNTAX;
+
+	while (*expr) {
+		/* Skip white space */
+		for (; expr && *expr && isspace(*expr); ++expr);
+
+		if (*expr == '+') {
+			++expr;
+			if (eval_expr_multdiv(&expr, &arg) != 0)
+				return WRDE_SYNTAX;
+
+			*result += arg;
+		} else if (*expr == '-') {
+			++expr;
+			if (eval_expr_multdiv(&expr, &arg) != 0)
+				return WRDE_SYNTAX;
+
+			*result -= arg;
+		} else
+			break;
+	}
+
+	return 0;
+}
+
+static int
+parse_arith(char **word, size_t * word_length, size_t * max_length,
+			const char *words, size_t * offset, int flags, int bracket)
+{
+	/* We are poised just after "$((" or "$[" */
+	int error;
+	int paren_depth = 1;
+	size_t expr_length;
+	size_t expr_maxlen;
+	char *expr;
+
+	expr = w_newword(&expr_length, &expr_maxlen);
+	for (; words[*offset]; ++(*offset)) {
+		switch (words[*offset]) {
+		case '$':
+			error = parse_dollars(&expr, &expr_length, &expr_maxlen,
+								  words, offset, flags, NULL, NULL, NULL,
+								  1);
+			/* The ``1'' here is to tell parse_dollars not to
+			 * split the fields.
+			 */
+			if (error) {
+				free(expr);
+				return error;
+			}
+			break;
+
+		case '`':
+			(*offset)++;
+			error = parse_backtick(&expr, &expr_length, &expr_maxlen,
+								   words, offset, flags, NULL, NULL, NULL);
+			/* The first NULL here is to tell parse_backtick not to
+			 * split the fields.
+			 */
+			if (error) {
+				free(expr);
+				return error;
+			}
+			break;
+
+		case '\\':
+			error = parse_qtd_backslash(&expr, &expr_length, &expr_maxlen,
+										words, offset);
+			if (error) {
+				free(expr);
+				return error;
+			}
+			/* I think that a backslash within an
+			 * arithmetic expansion is bound to
+			 * cause an error sooner or later anyway though.
+			 */
+			break;
+
+		case ')':
+			if (--paren_depth == 0) {
+				char result[21];	/* 21 = ceil(log10(2^64)) + 1 */
+				long int numresult = 0;
+				long long int convertme;
+
+				if (bracket || words[1 + *offset] != ')') {
+					free(expr);
+					return WRDE_SYNTAX;
+				}
+
+				++(*offset);
+
+				/* Go - evaluate. */
+				if (*expr && eval_expr(expr, &numresult) != 0) {
+					free(expr);
+					return WRDE_SYNTAX;
+				}
+
+				if (numresult < 0) {
+					convertme = -numresult;
+					*word = w_addchar(*word, word_length, max_length, '-');
+					if (!*word) {
+						free(expr);
+						return WRDE_NOSPACE;
+					}
+				} else
+					convertme = numresult;
+
+				result[20] = '\0';
+				*word = w_addstr(*word, word_length, max_length,
+								 _itoa(convertme, &result[20]));
+				free(expr);
+				return *word ? 0 : WRDE_NOSPACE;
+			}
+			expr =
+				w_addchar(expr, &expr_length, &expr_maxlen,
+						  words[*offset]);
+			if (expr == NULL)
+				return WRDE_NOSPACE;
+
+			break;
+
+		case ']':
+			if (bracket && paren_depth == 1) {
+				char result[21];	/* 21 = ceil(log10(2^64)) + 1 */
+				long int numresult = 0;
+
+				/* Go - evaluate. */
+				if (*expr && eval_expr(expr, &numresult) != 0) {
+					free(expr);
+					return WRDE_SYNTAX;
+				}
+
+				result[20] = '\0';
+				*word = w_addstr(*word, word_length, max_length,
+								 _itoa(numresult, &result[20]));
+				free(expr);
+				return *word ? 0 : WRDE_NOSPACE;
+			}
+
+			free(expr);
+			return WRDE_SYNTAX;
+
+		case '\n':
+		case ';':
+		case '{':
+		case '}':
+			free(expr);
+			return WRDE_BADCHAR;
+
+		case '(':
+			++paren_depth;
+		default:
+			expr =
+				w_addchar(expr, &expr_length, &expr_maxlen,
+						  words[*offset]);
+			if (expr == NULL)
+				return WRDE_NOSPACE;
+		}
+	}
+
+	/* Premature end */
+	free(expr);
+	return WRDE_SYNTAX;
+}
+
+/* Function called by child process in exec_comm() */
+static void
+exec_comm_child(char *comm, int *fildes, int showerr, int noexec)
+{
+	const char *args[4] = { _PATH_BSHELL, "-c", comm, NULL };
+
+	/* Execute the command, or just check syntax? */
+	if (noexec)
+		args[1] = "-nc";
+
+	/* Redirect output.  */
+	dup2(fildes[1], 1);
+	close(fildes[1]);
+
+	/* Redirect stderr to /dev/null if we have to.  */
+	if (showerr == 0) {
+		int fd;
+
+		close(2);
+		fd = open(_PATH_DEVNULL, O_WRONLY);
+		if (fd >= 0 && fd != 2) {
+			dup2(fd, 2);
+			close(fd);
+		}
+	}
+
+	/* Make sure the subshell doesn't field-split on our behalf. */
+	unsetenv("IFS");
+
+	close(fildes[0]);
+	execve(_PATH_BSHELL, (char *const *) args, __environ);
+
+	/* Bad.  What now?  */
+	abort();
+}
+
+/* Function to execute a command and retrieve the results */
+/* pwordexp contains NULL if field-splitting is forbidden */
+static int
+exec_comm(char *comm, char **word, size_t * word_length,
+		  size_t * max_length, int flags, wordexp_t * pwordexp,
+		  const char *ifs, const char *ifs_white)
+{
+	int fildes[2];
+	int bufsize = 128;
+	int buflen;
+	int i;
+	int status = 0;
+	size_t maxnewlines = 0;
+	char *buffer;
+	pid_t pid;
+
+	/* Don't fork() unless necessary */
+	if (!comm || !*comm)
+		return 0;
+
+	if (pipe(fildes))
+		/* Bad */
+		return WRDE_NOSPACE;
+
+	if ((pid = fork()) < 0) {
+		/* Bad */
+		close(fildes[0]);
+		close(fildes[1]);
+		return WRDE_NOSPACE;
+	}
+
+	if (pid == 0)
+		exec_comm_child(comm, fildes, (flags & WRDE_SHOWERR), 0);
+
+	/* Parent */
+
+	close(fildes[1]);
+	buffer = alloca(bufsize);
+
+	if (!pwordexp)
+		/* Quoted - no field splitting */
+	{
+		while (1) {
+			if ((buflen = read(fildes[0], buffer, bufsize)) < 1) {
+				if (waitpid(pid, &status, WNOHANG) == 0)
+					continue;
+				if ((buflen = read(fildes[0], buffer, bufsize)) < 1)
+					break;
+			}
+
+			maxnewlines += buflen;
+
+			*word = w_addmem(*word, word_length, max_length, buffer, buflen);
+			if (*word == NULL)
+				goto no_space;
+		}
+	} else
+		/* Not quoted - split fields */
+	{
+		int copying = 0;
+
+		/* 'copying' is:
+		 *  0 when searching for first character in a field not IFS white space
+		 *  1 when copying the text of a field
+		 *  2 when searching for possible non-whitespace IFS
+		 *  3 when searching for non-newline after copying field
+		 */
+
+		while (1) {
+			if ((buflen = read(fildes[0], buffer, bufsize)) < 1) {
+				if (waitpid(pid, &status, WNOHANG) == 0)
+					continue;
+				if ((buflen = read(fildes[0], buffer, bufsize)) < 1)
+					break;
+			}
+
+			for (i = 0; i < buflen; ++i) {
+				if (strchr(ifs, buffer[i]) != NULL) {
+					/* Current character is IFS */
+					if (strchr(ifs_white, buffer[i]) == NULL) {
+						/* Current character is IFS but not whitespace */
+						if (copying == 2) {
+							/*            current character
+							 *                   |
+							 *                   V
+							 * eg: text<space><comma><space>moretext
+							 *
+							 * So, strip whitespace IFS (like at the start)
+							 */
+							copying = 0;
+							continue;
+						}
+
+						copying = 0;
+						/* fall through and delimit field.. */
+					} else {
+						if (buffer[i] == '\n') {
+							/* Current character is (IFS) newline */
+
+							/* If copying a field, this is the end of it,
+							   but maybe all that's left is trailing newlines.
+							   So start searching for a non-newline. */
+							if (copying == 1)
+								copying = 3;
+
+							continue;
+						} else {
+							/* Current character is IFS white space, but
+							   not a newline */
+
+							/* If not either copying a field or searching
+							   for non-newline after a field, ignore it */
+							if (copying != 1 && copying != 3)
+								continue;
+
+							/* End of field (search for non-ws IFS afterwards) */
+							copying = 2;
+						}
+					}
+
+					/* First IFS white space (non-newline), or IFS non-whitespace.
+					 * Delimit the field.  Nulls are converted by w_addword. */
+					if (w_addword(pwordexp, *word) == WRDE_NOSPACE)
+						goto no_space;
+
+					*word = w_newword(word_length, max_length);
+
+					maxnewlines = 0;
+					/* fall back round the loop.. */
+				} else {
+					/* Not IFS character */
+
+					if (copying == 3) {
+						/* Nothing but (IFS) newlines since the last field,
+						   so delimit it here before starting new word */
+						if (w_addword(pwordexp, *word) == WRDE_NOSPACE)
+							goto no_space;
+
+						*word = w_newword(word_length, max_length);
+					}
+
+					copying = 1;
+
+					if (buffer[i] == '\n')	/* happens if newline not in IFS */
+						maxnewlines++;
+					else
+						maxnewlines = 0;
+
+					*word = w_addchar(*word, word_length, max_length,
+									  buffer[i]);
+					if (*word == NULL)
+						goto no_space;
+				}
+			}
+		}
+	}
+
+	/* Chop off trailing newlines (required by POSIX.2)  */
+	/* Ensure we don't go back further than the beginning of the
+	   substitution (i.e. remove maxnewlines bytes at most) */
+	while (maxnewlines-- != 0 &&
+		   *word_length > 0 && (*word)[*word_length - 1] == '\n') {
+		(*word)[--*word_length] = '\0';
+
+		/* If the last word was entirely newlines, turn it into a new word
+		 * which can be ignored if there's nothing following it. */
+		if (*word_length == 0) {
+			free(*word);
+			*word = w_newword(word_length, max_length);
+			break;
+		}
+	}
+
+	close(fildes[0]);
+
+	/* Check for syntax error (re-execute but with "-n" flag) */
+	if (buflen < 1 && status != 0) {
+		if ((pid = fork()) < 0) {
+			/* Bad */
+			return WRDE_NOSPACE;
+		}
+
+		if (pid == 0) {
+			fildes[0] = fildes[1] = -1;
+			exec_comm_child(comm, fildes, 0, 1);
+		}
+
+		if (waitpid(pid, &status, 0) == pid && status != 0)
+			return WRDE_SYNTAX;
+	}
+
+	return 0;
+
+  no_space:
+	kill(pid, SIGKILL);
+	waitpid(pid, NULL, 0);
+	close(fildes[0]);
+	return WRDE_NOSPACE;
+}
+
+static int
+parse_comm(char **word, size_t * word_length, size_t * max_length,
+		   const char *words, size_t * offset, int flags,
+		   wordexp_t * pwordexp, const char *ifs, const char *ifs_white)
+{
+	/* We are poised just after "$(" */
+	int paren_depth = 1;
+	int error = 0;
+	int quoted = 0;				/* 1 for singly-quoted, 2 for doubly-quoted */
+	size_t comm_length;
+	size_t comm_maxlen;
+	char *comm = w_newword(&comm_length, &comm_maxlen);
+
+	for (; words[*offset]; ++(*offset)) {
+		switch (words[*offset]) {
+		case '\'':
+			if (quoted == 0)
+				quoted = 1;
+			else if (quoted == 1)
+				quoted = 0;
+
+			break;
+
+		case '"':
+			if (quoted == 0)
+				quoted = 2;
+			else if (quoted == 2)
+				quoted = 0;
+
+			break;
+
+		case ')':
+			if (!quoted && --paren_depth == 0) {
+				/* Go -- give script to the shell */
+				if (comm) {
+					error = exec_comm(comm, word, word_length, max_length,
+									  flags, pwordexp, ifs, ifs_white);
+					free(comm);
+				}
+
+				return error;
+			}
+
+			/* This is just part of the script */
+			break;
+
+		case '(':
+			if (!quoted)
+				++paren_depth;
+		}
+
+		comm = w_addchar(comm, &comm_length, &comm_maxlen, words[*offset]);
+		if (comm == NULL)
+			return WRDE_NOSPACE;
+	}
+
+	/* Premature end */
+	if (comm)
+		free(comm);
+
+	return WRDE_SYNTAX;
+}
+
+static int
+parse_backtick(char **word, size_t * word_length, size_t * max_length,
+			   const char *words, size_t * offset, int flags,
+			   wordexp_t * pwordexp, const char *ifs,
+			   const char *ifs_white)
+{
+	/* We are poised just after "`" */
+	int error;
+	int squoting = 0;
+	size_t comm_length;
+	size_t comm_maxlen;
+	char *comm = w_newword(&comm_length, &comm_maxlen);
+
+	for (; words[*offset]; ++(*offset)) {
+		switch (words[*offset]) {
+		case '`':
+			/* Go -- give the script to the shell */
+			error = exec_comm(comm, word, word_length, max_length, flags,
+							  pwordexp, ifs, ifs_white);
+			free(comm);
+			return error;
+
+		case '\\':
+			if (squoting) {
+				error = parse_qtd_backslash(&comm, &comm_length, &comm_maxlen,
+										words, offset);
+
+				if (error) {
+					free(comm);
+					return error;
+				}
+
+				break;
+			}
+
+			++(*offset);
+			error = parse_backslash(&comm, &comm_length, &comm_maxlen, words,
+								offset);
+
+			if (error) {
+				free(comm);
+				return error;
+			}
+
+			break;
+
+		case '\'':
+			squoting = 1 - squoting;
+		default:
+			comm = w_addchar(comm, &comm_length, &comm_maxlen,
+						  words[*offset]);
+			if (comm == NULL)
+				return WRDE_NOSPACE;
+		}
+	}
+
+	/* Premature end */
+	free(comm);
+	return WRDE_SYNTAX;
+}
+
+static int
+parse_param(char **word, size_t * word_length, size_t * max_length,
+			const char *words, size_t * offset, int flags,
+			wordexp_t * pwordexp, const char *ifs, const char *ifs_white,
+			int quoted)
+{
+	/* We are poised just after "$" */
+	enum action {
+		ACT_NONE,
+		ACT_RP_SHORT_LEFT = '#',
+		ACT_RP_LONG_LEFT = 'L',
+		ACT_RP_SHORT_RIGHT = '%',
+		ACT_RP_LONG_RIGHT = 'R',
+		ACT_NULL_ERROR = '?',
+		ACT_NULL_SUBST = '-',
+		ACT_NONNULL_SUBST = '+',
+		ACT_NULL_ASSIGN = '='
+	};
+	size_t env_length;
+	size_t env_maxlen;
+	size_t pat_length;
+	size_t pat_maxlen;
+	size_t start = *offset;
+	char *env;
+	char *pattern;
+	char *value = NULL;
+	enum action action = ACT_NONE;
+	int depth = 0;
+	int colon_seen = 0;
+	int seen_hash = 0;
+	int free_value = 0;
+	int pattern_is_quoted = 0;	/* 1 for singly-quoted, 2 for doubly-quoted */
+	int error;
+	int special = 0;
+	char buffer[21];
+	int brace = words[*offset] == '{';
+
+	env = w_newword(&env_length, &env_maxlen);
+	pattern = w_newword(&pat_length, &pat_maxlen);
+
+	if (brace)
+		++ * offset;
+
+	/* First collect the parameter name. */
+
+	if (words[*offset] == '#') {
+		seen_hash = 1;
+		if (!brace)
+			goto envsubst;
+		++*offset;
+	}
+
+	if (isalpha(words[*offset]) || words[*offset] == '_') {
+		/* Normal parameter name. */
+		do {
+			env = w_addchar(env, &env_length, &env_maxlen, words[*offset]);
+			if (env == NULL)
+				goto no_space;
+		}
+		while (isalnum(words[++*offset]) || words[*offset] == '_');