cli_hush.c

#ifndef __U_BOOT__
	if (fake_mode==0) {
#endif
		rcode = run_list_real(pi);
#ifndef __U_BOOT__
	}
#endif
	/* free_pipe_list has the side effect of clearing memory
	 * In the long run that function can be merged with run_list_real,
	 * but doing that now would hobble the debugging effort. */
	free_pipe_list(pi,0);
	return rcode;
}

/* The API for glob is arguably broken.  This routine pushes a non-matching
 * string into the output structure, removing non-backslashed backslashes.
 * If someone can prove me wrong, by performing this function within the
 * original glob(3) api, feel free to rewrite this routine into oblivion.
 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
 * XXX broken if the last character is '\\', check that before calling.
 */
#ifndef __U_BOOT__
static int globhack(const char *src, int flags, glob_t *pglob)
{
	int cnt=0, pathc;
	const char *s;
	char *dest;
	for (cnt=1, s=src; s && *s; s++) {
		if (*s == '\\') s++;
		cnt++;
	}
	dest = malloc(cnt);
	if (!dest) return GLOB_NOSPACE;
	if (!(flags & GLOB_APPEND)) {
		pglob->gl_pathv=NULL;
		pglob->gl_pathc=0;
		pglob->gl_offs=0;
		pglob->gl_offs=0;
	}
	pathc = ++pglob->gl_pathc;
	pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
	if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
	pglob->gl_pathv[pathc-1]=dest;
	pglob->gl_pathv[pathc]=NULL;
	for (s=src; s && *s; s++, dest++) {
		if (*s == '\\') s++;
		*dest = *s;
	}
	*dest='\0';
	return 0;
}

/* XXX broken if the last character is '\\', check that before calling */
static int glob_needed(const char *s)
{
	for (; *s; s++) {
		if (*s == '\\') s++;
		if (strchr("*[?",*s)) return 1;
	}
	return 0;
}

#if 0
static void globprint(glob_t *pglob)
{
	int i;
	debug_printf("glob_t at %p:\n", pglob);
	debug_printf("  gl_pathc=%d  gl_pathv=%p  gl_offs=%d  gl_flags=%d\n",
		pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
	for (i=0; i<pglob->gl_pathc; i++)
		debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
			pglob->gl_pathv[i], pglob->gl_pathv[i]);
}
#endif

static int xglob(o_string *dest, int flags, glob_t *pglob)
{
	int gr;

	/* short-circuit for null word */
	/* we can code this better when the debug_printf's are gone */
	if (dest->length == 0) {
		if (dest->nonnull) {
			/* bash man page calls this an "explicit" null */
			gr = globhack(dest->data, flags, pglob);
			debug_printf("globhack returned %d\n",gr);
		} else {
			return 0;
		}
	} else if (glob_needed(dest->data)) {
		gr = glob(dest->data, flags, NULL, pglob);
		debug_printf("glob returned %d\n",gr);
		if (gr == GLOB_NOMATCH) {
			/* quote removal, or more accurately, backslash removal */
			gr = globhack(dest->data, flags, pglob);
			debug_printf("globhack returned %d\n",gr);
		}
	} else {
		gr = globhack(dest->data, flags, pglob);
		debug_printf("globhack returned %d\n",gr);
	}
	if (gr == GLOB_NOSPACE)
		error_msg_and_die("out of memory during glob");
	if (gr != 0) { /* GLOB_ABORTED ? */
		error_msg("glob(3) error %d",gr);
	}
	/* globprint(glob_target); */
	return gr;
}
#endif

#ifdef __U_BOOT__
static char *get_dollar_var(char ch);
#endif

/* This is used to get/check local shell variables */
char *get_local_var(const char *s)
{
	struct variables *cur;

	if (!s)
		return NULL;

#ifdef __U_BOOT__
	if (*s == '$')
		return get_dollar_var(s[1]);
#endif

	for (cur = top_vars; cur; cur=cur->next)
		if(strcmp(cur->name, s)==0)
			return cur->value;
	return NULL;
}

/* This is used to set local shell variables
   flg_export==0 if only local (not exporting) variable
   flg_export==1 if "new" exporting environ
   flg_export>1  if current startup environ (not call putenv()) */
int set_local_var(const char *s, int flg_export)
{
	char *name, *value;
	int result=0;
	struct variables *cur;

#ifdef __U_BOOT__
	/* might be possible! */
	if (!isalpha(*s))
		return -1;
#endif

	name=strdup(s);

#ifdef __U_BOOT__
	if (getenv(name) != NULL) {
		printf ("ERROR: "
				"There is a global environment variable with the same name.\n");
		free(name);
		return -1;
	}
#endif
	/* Assume when we enter this function that we are already in
	 * NAME=VALUE format.  So the first order of business is to
	 * split 's' on the '=' into 'name' and 'value' */
	value = strchr(name, '=');
	if (value == NULL && ++value == NULL) {
		free(name);
		return -1;
	}
	*value++ = 0;

	for(cur = top_vars; cur; cur = cur->next) {
		if(strcmp(cur->name, name)==0)
			break;
	}

	if(cur) {
		if(strcmp(cur->value, value)==0) {
			if(flg_export>0 && cur->flg_export==0)
				cur->flg_export=flg_export;
			else
				result++;
		} else {
			if(cur->flg_read_only) {
				error_msg("%s: readonly variable", name);
				result = -1;
			} else {
				if(flg_export>0 || cur->flg_export>1)
					cur->flg_export=1;
				free(cur->value);

				cur->value = strdup(value);
			}
		}
	} else {
		cur = malloc(sizeof(struct variables));
		if(!cur) {
			result = -1;
		} else {
			cur->name = strdup(name);
			if (cur->name == NULL) {
				free(cur);
				result = -1;
			} else {
				struct variables *bottom = top_vars;
				cur->value = strdup(value);
				cur->next = NULL;
				cur->flg_export = flg_export;
				cur->flg_read_only = 0;
				while(bottom->next) bottom=bottom->next;
				bottom->next = cur;
			}
		}
	}

#ifndef __U_BOOT__
	if(result==0 && cur->flg_export==1) {
		*(value-1) = '=';
		result = putenv(name);
	} else {
#endif
		free(name);
#ifndef __U_BOOT__
		if(result>0)            /* equivalent to previous set */
			result = 0;
	}
#endif
	return result;
}

void unset_local_var(const char *name)
{
	struct variables *cur;

	if (name) {
		for (cur = top_vars; cur; cur=cur->next) {
			if(strcmp(cur->name, name)==0)
				break;
		}
		if (cur != NULL) {
			struct variables *next = top_vars;
			if(cur->flg_read_only) {
				error_msg("%s: readonly variable", name);
				return;
			} else {
#ifndef __U_BOOT__
				if(cur->flg_export)
					unsetenv(cur->name);
#endif
				free(cur->name);
				free(cur->value);
				while (next->next != cur)
					next = next->next;
				next->next = cur->next;
			}
			free(cur);
		}
	}
}

static int is_assignment(const char *s)
{
	if (s == NULL)
		return 0;

	if (!isalpha(*s)) return 0;
	++s;
	while(isalnum(*s) || *s=='_') ++s;
	return *s=='=';
}

#ifndef __U_BOOT__
/* the src parameter allows us to peek forward to a possible &n syntax
 * for file descriptor duplication, e.g., "2>&1".
 * Return code is 0 normally, 1 if a syntax error is detected in src.
 * Resource errors (in xmalloc) cause the process to exit */
static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
	struct in_str *input)
{
	struct child_prog *child=ctx->child;
	struct redir_struct *redir = child->redirects;
	struct redir_struct *last_redir=NULL;

	/* Create a new redir_struct and drop it onto the end of the linked list */
	while(redir) {
		last_redir=redir;
		redir=redir->next;
	}
	redir = xmalloc(sizeof(struct redir_struct));
	redir->next=NULL;
	redir->word.gl_pathv=NULL;
	if (last_redir) {
		last_redir->next=redir;
	} else {
		child->redirects=redir;
	}

	redir->type=style;
	redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;

	debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);

	/* Check for a '2>&1' type redirect */
	redir->dup = redirect_dup_num(input);
	if (redir->dup == -2) return 1;  /* syntax error */
	if (redir->dup != -1) {
		/* Erik had a check here that the file descriptor in question
		 * is legit; I postpone that to "run time"
		 * A "-" representation of "close me" shows up as a -3 here */
		debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
	} else {
		/* We do _not_ try to open the file that src points to,
		 * since we need to return and let src be expanded first.
		 * Set ctx->pending_redirect, so we know what to do at the
		 * end of the next parsed word.
		 */
		ctx->pending_redirect = redir;
	}
	return 0;
}
#endif

static struct pipe *new_pipe(void)
{
	struct pipe *pi;
	pi = xmalloc(sizeof(struct pipe));
	pi->num_progs = 0;
	pi->progs = NULL;
	pi->next = NULL;
	pi->followup = 0;  /* invalid */
	pi->r_mode = RES_NONE;
	return pi;
}

static void initialize_context(struct p_context *ctx)
{
	ctx->pipe=NULL;
#ifndef __U_BOOT__
	ctx->pending_redirect=NULL;
#endif
	ctx->child=NULL;
	ctx->list_head=new_pipe();
	ctx->pipe=ctx->list_head;
	ctx->w=RES_NONE;
	ctx->stack=NULL;
#ifdef __U_BOOT__
	ctx->old_flag=0;
#endif
	done_command(ctx);   /* creates the memory for working child */
}

/* normal return is 0
 * if a reserved word is found, and processed, return 1
 * should handle if, then, elif, else, fi, for, while, until, do, done.
 * case, function, and select are obnoxious, save those for later.
 */
struct reserved_combo {
	char *literal;
	int code;
	long flag;
};
/* Mostly a list of accepted follow-up reserved words.
 * FLAG_END means we are done with the sequence, and are ready
 * to turn the compound list into a command.
 * FLAG_START means the word must start a new compound list.
 */
static struct reserved_combo reserved_list[] = {
	{ "if",    RES_IF,    FLAG_THEN | FLAG_START },
	{ "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
	{ "elif",  RES_ELIF,  FLAG_THEN },
	{ "else",  RES_ELSE,  FLAG_FI   },
	{ "fi",    RES_FI,    FLAG_END  },
	{ "for",   RES_FOR,   FLAG_IN   | FLAG_START },
	{ "while", RES_WHILE, FLAG_DO   | FLAG_START },
	{ "until", RES_UNTIL, FLAG_DO   | FLAG_START },
	{ "in",    RES_IN,    FLAG_DO   },
	{ "do",    RES_DO,    FLAG_DONE },
	{ "done",  RES_DONE,  FLAG_END  }
};
#define NRES (sizeof(reserved_list)/sizeof(struct reserved_combo))

static int reserved_word(o_string *dest, struct p_context *ctx)
{
	struct reserved_combo *r;
	for (r=reserved_list;
		r<reserved_list+NRES; r++) {
		if (strcmp(dest->data, r->literal) == 0) {
			debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
			if (r->flag & FLAG_START) {
				struct p_context *new = xmalloc(sizeof(struct p_context));
				debug_printf("push stack\n");
				if (ctx->w == RES_IN || ctx->w == RES_FOR) {
					syntax();
					free(new);
					ctx->w = RES_SNTX;
					b_reset(dest);
					return 1;
				}
				*new = *ctx;   /* physical copy */
				initialize_context(ctx);
				ctx->stack=new;
			} else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
				syntax();
				ctx->w = RES_SNTX;
				b_reset(dest);
				return 1;
			}
			ctx->w=r->code;
			ctx->old_flag = r->flag;
			if (ctx->old_flag & FLAG_END) {
				struct p_context *old;
				debug_printf("pop stack\n");
				done_pipe(ctx,PIPE_SEQ);
				old = ctx->stack;
				old->child->group = ctx->list_head;
#ifndef __U_BOOT__
				old->child->subshell = 0;
#endif
				*ctx = *old;   /* physical copy */
				free(old);
			}
			b_reset (dest);
			return 1;
		}
	}
	return 0;
}

/* normal return is 0.
 * Syntax or xglob errors return 1. */
static int done_word(o_string *dest, struct p_context *ctx)
{
	struct child_prog *child=ctx->child;
#ifndef __U_BOOT__
	glob_t *glob_target;
	int gr, flags = 0;
#else
	char *str, *s;
	int argc, cnt;
#endif

	debug_printf("done_word: %s %p\n", dest->data, child);
	if (dest->length == 0 && !dest->nonnull) {
		debug_printf("  true null, ignored\n");
		return 0;
	}
#ifndef __U_BOOT__
	if (ctx->pending_redirect) {
		glob_target = &ctx->pending_redirect->word;
	} else {
#endif
		if (child->group) {
			syntax();
			return 1;  /* syntax error, groups and arglists don't mix */
		}
		if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
			debug_printf("checking %s for reserved-ness\n",dest->data);
			if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
		}
#ifndef __U_BOOT__
		glob_target = &child->glob_result;
		if (child->argv) flags |= GLOB_APPEND;
#else
		for (cnt = 1, s = dest->data; s && *s; s++) {
			if (*s == '\\') s++;
			cnt++;
		}
		str = malloc(cnt);
		if (!str) return 1;
		if ( child->argv == NULL) {
			child->argc=0;
		}
		argc = ++child->argc;
		child->argv = realloc(child->argv, (argc+1)*sizeof(*child->argv));
		if (child->argv == NULL) return 1;
		child->argv_nonnull = realloc(child->argv_nonnull,
					(argc+1)*sizeof(*child->argv_nonnull));
		if (child->argv_nonnull == NULL)
			return 1;
		child->argv[argc-1]=str;
		child->argv_nonnull[argc-1] = dest->nonnull;
		child->argv[argc]=NULL;
		child->argv_nonnull[argc] = 0;
		for (s = dest->data; s && *s; s++,str++) {
			if (*s == '\\') s++;
			*str = *s;
		}
		*str = '\0';
#endif
#ifndef __U_BOOT__
	}
	gr = xglob(dest, flags, glob_target);
	if (gr != 0) return 1;
#endif

	b_reset(dest);
#ifndef __U_BOOT__
	if (ctx->pending_redirect) {
		ctx->pending_redirect=NULL;
		if (glob_target->gl_pathc != 1) {
			error_msg("ambiguous redirect");
			return 1;
		}
	} else {
		child->argv = glob_target->gl_pathv;
	}
#endif
	if (ctx->w == RES_FOR) {
		done_word(dest,ctx);
		done_pipe(ctx,PIPE_SEQ);
	}
	return 0;
}

/* The only possible error here is out of memory, in which case
 * xmalloc exits. */
static int done_command(struct p_context *ctx)
{
	/* The child is really already in the pipe structure, so
	 * advance the pipe counter and make a new, null child.
	 * Only real trickiness here is that the uncommitted
	 * child structure, to which ctx->child points, is not
	 * counted in pi->num_progs. */
	struct pipe *pi=ctx->pipe;
	struct child_prog *prog=ctx->child;

	if (prog && prog->group == NULL
		 && prog->argv == NULL
#ifndef __U_BOOT__
		 && prog->redirects == NULL) {
#else
										) {
#endif
		debug_printf("done_command: skipping null command\n");
		return 0;
	} else if (prog) {
		pi->num_progs++;
		debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
	} else {
		debug_printf("done_command: initializing\n");
	}
	pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));

	prog = pi->progs + pi->num_progs;
#ifndef __U_BOOT__
	prog->redirects = NULL;
#endif
	prog->argv = NULL;
	prog->argv_nonnull = NULL;
#ifndef __U_BOOT__
	prog->is_stopped = 0;
#endif
	prog->group = NULL;
#ifndef __U_BOOT__
	prog->glob_result.gl_pathv = NULL;
	prog->family = pi;
#endif
	prog->sp = 0;
	ctx->child = prog;
	prog->type = ctx->type;

	/* but ctx->pipe and ctx->list_head remain unchanged */
	return 0;
}

static int done_pipe(struct p_context *ctx, pipe_style type)
{
	struct pipe *new_p;
	done_command(ctx);  /* implicit closure of previous command */
	debug_printf("done_pipe, type %d\n", type);
	ctx->pipe->followup = type;
	ctx->pipe->r_mode = ctx->w;
	new_p=new_pipe();
	ctx->pipe->next = new_p;
	ctx->pipe = new_p;
	ctx->child = NULL;
	done_command(ctx);  /* set up new pipe to accept commands */
	return 0;
}

#ifndef __U_BOOT__
/* peek ahead in the in_str to find out if we have a "&n" construct,
 * as in "2>&1", that represents duplicating a file descriptor.
 * returns either -2 (syntax error), -1 (no &), or the number found.
 */
static int redirect_dup_num(struct in_str *input)
{
	int ch, d=0, ok=0;
	ch = b_peek(input);
	if (ch != '&') return -1;

	b_getch(input);  /* get the & */
	ch=b_peek(input);
	if (ch == '-') {
		b_getch(input);
		return -3;  /* "-" represents "close me" */
	}
	while (isdigit(ch)) {
		d = d*10+(ch-'0');
		ok=1;
		b_getch(input);
		ch = b_peek(input);
	}
	if (ok) return d;

	error_msg("ambiguous redirect");
	return -2;
}

/* If a redirect is immediately preceded by a number, that number is
 * supposed to tell which file descriptor to redirect.  This routine
 * looks for such preceding numbers.  In an ideal world this routine
 * needs to handle all the following classes of redirects...
 *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
 *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
 *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
 *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
 * A -1 output from this program means no valid number was found, so the
 * caller should use the appropriate default for this redirection.
 */
static int redirect_opt_num(o_string *o)
{
	int num;

	if (o->length==0) return -1;
	for(num=0; num<o->length; num++) {
		if (!isdigit(*(o->data+num))) {
			return -1;
		}
	}
	/* reuse num (and save an int) */
	num=atoi(o->data);
	b_reset(o);
	return num;
}

FILE *generate_stream_from_list(struct pipe *head)
{
	FILE *pf;
#if 1
	int pid, channel[2];
	if (pipe(channel)<0) perror_msg_and_die("pipe");
	pid=fork();
	if (pid<0) {
		perror_msg_and_die("fork");
	} else if (pid==0) {
		close(channel[0]);
		if (channel[1] != 1) {
			dup2(channel[1],1);
			close(channel[1]);
		}
#if 0
#define SURROGATE "surrogate response"
		write(1,SURROGATE,sizeof(SURROGATE));
		_exit(run_list(head));
#else
		_exit(run_list_real(head));   /* leaks memory */
#endif
	}
	debug_printf("forked child %d\n",pid);
	close(channel[1]);
	pf = fdopen(channel[0],"r");
	debug_printf("pipe on FILE *%p\n",pf);
#else
	free_pipe_list(head,0);
	pf=popen("echo surrogate response","r");
	debug_printf("started fake pipe on FILE *%p\n",pf);
#endif
	return pf;
}

/* this version hacked for testing purposes */
/* return code is exit status of the process that is run. */
static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
{
	int retcode;
	o_string result=NULL_O_STRING;
	struct p_context inner;
	FILE *p;
	struct in_str pipe_str;
	initialize_context(&inner);

	/* recursion to generate command */
	retcode = parse_stream(&result, &inner, input, subst_end);
	if (retcode != 0) return retcode;  /* syntax error or EOF */
	done_word(&result, &inner);
	done_pipe(&inner, PIPE_SEQ);
	b_free(&result);

	p=generate_stream_from_list(inner.list_head);
	if (p==NULL) return 1;
	mark_open(fileno(p));
	setup_file_in_str(&pipe_str, p);

	/* now send results of command back into original context */
	retcode = parse_stream(dest, ctx, &pipe_str, '\0');
	/* XXX In case of a syntax error, should we try to kill the child?
	 * That would be tough to do right, so just read until EOF. */
	if (retcode == 1) {
		while (b_getch(&pipe_str)!=EOF) { /* discard */ };
	}

	debug_printf("done reading from pipe, pclose()ing\n");
	/* This is the step that wait()s for the child.  Should be pretty
	 * safe, since we just read an EOF from its stdout.  We could try
	 * to better, by using wait(), and keeping track of background jobs
	 * at the same time.  That would be a lot of work, and contrary
	 * to the KISS philosophy of this program. */
	mark_closed(fileno(p));
	retcode=pclose(p);
	free_pipe_list(inner.list_head,0);
	debug_printf("pclosed, retcode=%d\n",retcode);
	/* XXX this process fails to trim a single trailing newline */
	return retcode;
}

static int parse_group(o_string *dest, struct p_context *ctx,
	struct in_str *input, int ch)
{
	int rcode, endch=0;
	struct p_context sub;
	struct child_prog *child = ctx->child;
	if (child->argv) {
		syntax();
		return 1;  /* syntax error, groups and arglists don't mix */
	}
	initialize_context(&sub);
	switch(ch) {
		case '(': endch=')'; child->subshell=1; break;
		case '{': endch='}'; break;
		default: syntax();   /* really logic error */
	}
	rcode=parse_stream(dest,&sub,input,endch);
	done_word(dest,&sub); /* finish off the final word in the subcontext */
	done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
	child->group = sub.list_head;
	return rcode;
	/* child remains "open", available for possible redirects */
}
#endif

/* basically useful version until someone wants to get fancier,
 * see the bash man page under "Parameter Expansion" */
static char *lookup_param(char *src)
{
	char *p;
	char *sep;
	char *default_val = NULL;
	int assign = 0;
	int expand_empty = 0;

	if (!src)
		return NULL;

	sep = strchr(src, ':');

	if (sep) {
		*sep = '\0';
		if (*(sep + 1) == '-')
			default_val = sep+2;
		if (*(sep + 1) == '=') {
			default_val = sep+2;
			assign = 1;
		}
		if (*(sep + 1) == '+') {
			default_val = sep+2;
			expand_empty = 1;
		}
	}

	p = getenv(src);
	if (!p)
		p = get_local_var(src);

	if (!p || strlen(p) == 0) {
		p = default_val;
		if (assign) {
			char *var = malloc(strlen(src)+strlen(default_val)+2);
			if (var) {
				sprintf(var, "%s=%s", src, default_val);
				set_local_var(var, 0);
			}
			free(var);
		}
	} else if (expand_empty) {
		p += strlen(p);
	}

	if (sep)
		*sep = ':';

	return p;
}

#ifdef __U_BOOT__
static char *get_dollar_var(char ch)
{
	static char buf[40];

	buf[0] = '\0';
	switch (ch) {
		case '?':
			sprintf(buf, "%u", (unsigned int)last_return_code);
			break;
		default:
			return NULL;
	}
	return buf;
}
#endif

/* return code: 0 for OK, 1 for syntax error */
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
{
#ifndef __U_BOOT__
	int i, advance=0;
#else
	int advance=0;
#endif
#ifndef __U_BOOT__
	char sep[]=" ";
#endif
	int ch = input->peek(input);  /* first character after the $ */
	debug_printf("handle_dollar: ch=%c\n",ch);
	if (isalpha(ch)) {
		b_addchr(dest, SPECIAL_VAR_SYMBOL);
		ctx->child->sp++;
		while(ch=b_peek(input),isalnum(ch) || ch=='_') {
			b_getch(input);
			b_addchr(dest,ch);
		}
		b_addchr(dest, SPECIAL_VAR_SYMBOL);
#ifndef __U_BOOT__
	} else if (isdigit(ch)) {
		i = ch-'0';  /* XXX is $0 special? */
		if (i<global_argc) {
			parse_string(dest, ctx, global_argv[i]); /* recursion */
		}
		advance = 1;
#endif
	} else switch (ch) {
#ifndef __U_BOOT__
		case '$':
			b_adduint(dest,getpid());
			advance = 1;
			break;
		case '!':
			if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
			advance = 1;
			break;
#endif
		case '?':
#ifndef __U_BOOT__
			b_adduint(dest,last_return_code);
#else
			ctx->child->sp++;
			b_addchr(dest, SPECIAL_VAR_SYMBOL);
			b_addchr(dest, '$');
			b_addchr(dest, '?');
			b_addchr(dest, SPECIAL_VAR_SYMBOL);
#endif
			advance = 1;
			break;
#ifndef __U_BOOT__
		case '#':
			b_adduint(dest,global_argc ? global_argc-1 : 0);
			advance = 1;
			break;
#endif
		case '{':
			b_addchr(dest, SPECIAL_VAR_SYMBOL);
			ctx->child->sp++;
			b_getch(input);
			/* XXX maybe someone will try to escape the '}' */
			while(ch=b_getch(input),ch!=EOF && ch!='}') {
				b_addchr(dest,ch);
			}
			if (ch != '}') {
				syntax();
				return 1;
			}
			b_addchr(dest, SPECIAL_VAR_SYMBOL);
			break;
#ifndef __U_BOOT__
		case '(':
			b_getch(input);
			process_command_subs(dest, ctx, input, ')');
			break;
		case '*':
			sep[0]=ifs[0];
			for (i=1; i<global_argc; i++) {
				parse_string(dest, ctx, global_argv[i]);
				if (i+1 < global_argc) parse_string(dest, ctx, sep);
			}
			break;
		case '@':
		case '-':
		case '_':
			/* still unhandled, but should be eventually */
			error_msg("unhandled syntax: $%c",ch);
			return 1;
			break;
#endif
		default:
			b_addqchr(dest,'$',dest->quote);
	}
	/* Eat the character if the flag was set.  If the compiler
	 * is smart enough, we could substitute "b_getch(input);"
	 * for all the "advance = 1;" above, and also end up with
	 * a nice size-optimized program.  Hah!  That'll be the day.
	 */
	if (advance) b_getch(input);
	return 0;
}

#ifndef __U_BOOT__
int parse_string(o_string *dest, struct p_context *ctx, const char *src)
{
	struct in_str foo;
	setup_string_in_str(&foo, src);
	return parse_stream(dest, ctx, &foo, '\0');
}
#endif

/* return code is 0 for normal exit, 1 for syntax error */
static int parse_stream(o_string *dest, struct p_context *ctx,
			struct in_str *input, int end_trigger)
{
	unsigned int ch, m;
#ifndef __U_BOOT__
	int redir_fd;
	redir_type redir_style;
#endif
	int next;

	/* Only double-quote state is handled in the state variable dest->quote.
	 * A single-quote triggers a bypass of the main loop until its mate is
	 * found.  When recursing, quote state is passed in via dest->quote. */

	debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
	while ((ch=b_getch(input))!=EOF) {
		m = map[ch];
#ifdef __U_BOOT__
		if (input->__promptme == 0) return 1;
#endif
		next = (ch == '\n') ? 0 : b_peek(input);

		debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d - %c\n",
			ch >= ' ' ? ch : '.', ch, m,
			dest->quote, ctx->stack == NULL ? '*' : '.');

		if (m==0 || ((m==1 || m==2) && dest->quote)) {
			b_addqchr(dest, ch, dest->quote);
		} else {
			if (m==2) {  /* unquoted IFS */
				if (done_word(dest, ctx)) {
					return 1;
				}
				/* If we aren't performing a substitution, treat a newline as a
				 * command separator.  */
				if (end_trigger != '\0' && ch=='\n')
					done_pipe(ctx,PIPE_SEQ);
			}
			if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
				debug_printf("leaving parse_stream (triggered)\n");
				return 0;
			}
#if 0
			if (ch=='\n') {
				/* Yahoo!  Time to run with it! */
				done_pipe(ctx,PIPE_SEQ);
				run_list(ctx->list_head);
				initialize_context(ctx);
			}
#endif
			if (m!=2) switch (ch) {
		case '#':
			if (dest->length == 0 && !dest->quote) {
				while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
			} else {
				b_addqchr(dest, ch, dest->quote);
			}
			break;
		case '\\':
			if (next == EOF) {
				syntax();
				return 1;
			}
			b_addqchr(dest, '\\', dest->quote);
			b_addqchr(dest, b_getch(input), dest->quote);
			break;
		case '$':
			if (handle_dollar(dest, ctx, input)!=0) return 1;
			break;
		case '\'':
			dest->nonnull = 1;
			while(ch=b_getch(input),ch!=EOF && ch!='\'') {
#ifdef __U_BOOT__
				if(input->__promptme == 0) return 1;
#endif
				b_addchr(dest,ch);