This is the initial checkin of Larry Doolittle's hush.c, using his

April 25, 2001 snapshot, adjusted a bit by me so it has cmdedit support.

This checkin also removes sh.c.  In the future sh.c will be a symlink to
your shell of choice.  For now, this symlink will default to pointing to
lash.c (as in the past).  If you change the symlink to point to hush.c,
then thats what you will get.  This symlink business is a temporary situation,
which will be cleaned up Real Soon Now(tm).

 -Erik

1 files changed, 2191 insertions, 0 deletions

diff --git a/shell/hush.c b/shell/hush.c
new file mode 100644
index 0000000..f2a4ea4
--- /dev/null
+++ b/shell/hush.c
@@ -0,0 +1,2191 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * sh.c -- a prototype Bourne shell grammar parser
+ *      Intended to follow the original Thompson and Ritchie
+ *      "small and simple is beautiful" philosophy, which
+ *      incidentally is a good match to today's BusyBox.
+ *
+ * Copyright (C) 2000,2001  Larry Doolittle  <larry@doolittle.boa.org>
+ *
+ * Credits:
+ *      The parser routines proper are all original material, first
+ *      written Dec 2000 and Jan 2001 by Larry Doolittle.
+ *      The execution engine, the builtins, and much of the underlying
+ *      support has been adapted from busybox-0.49pre's lash,
+ *      which is Copyright (C) 2000 by Lineo, Inc., and
+ *      written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
+ *      That, in turn, is based in part on ladsh.c, by Michael K. Johnson and
+ *      Erik W. Troan, which they placed in the public domain.  I don't know
+ *      how much of the Johnson/Troan code has survived the repeated rewrites.
+ * Other credits:
+ *      simple_itoa() was lifted from boa-0.93.15
+ *      b_addchr() derived from similar w_addchar function in glibc-2.2
+ *      setup_redirect(), redirect_opt_num(), and big chunks of main()
+ *        and many builtins derived from contributions by Erik Andersen
+ *      miscellaneous bugfixes from Matt Kraai
+ *
+ * There are two big (and related) architecture differences between
+ * this parser and the lash parser.  One is that this version is
+ * actually designed from the ground up to understand nearly all
+ * of the Bourne grammar.  The second, consequential change is that
+ * the parser and input reader have been turned inside out.  Now,
+ * the parser is in control, and asks for input as needed.  The old
+ * way had the input reader in control, and it asked for parsing to
+ * take place as needed.  The new way makes it much easier to properly
+ * handle the recursion implicit in the various substitutions, especially
+ * across continuation lines.
+ *
+ * Bash grammar not implemented: (how many of these were in original sh?)
+ *      $@ (those sure look like weird quoting rules)
+ *      $_
+ *      ! negation operator for pipes
+ *      &> and >& redirection of stdout+stderr
+ *      Brace Expansion
+ *      Tilde Expansion
+ *      fancy forms of Parameter Expansion
+ *      Arithmetic Expansion
+ *      <(list) and >(list) Process Substitution
+ *      reserved words: if, then, elif, else, fi, while, until, for,
+ *                      do, done, case
+ *      Here Documents ( << word )
+ *      Functions
+ * Major bugs:
+ *      job handling woefully incomplete and buggy
+ *      reserved word execution woefully incomplete and buggy
+ *      incomplete reserved word sequence doesn't request more lines of input
+ * to-do:
+ *      port selected bugfixes from post-0.49 busybox lash
+ *      finish implementing reserved words
+ *      handle children going into background
+ *      clean up recognition of null pipes
+ *      have builtin_exec set flag to avoid restore_redirects
+ *      figure out if "echo foo}" is fixable
+ *      check setting of global_argc and global_argv
+ *      control-C handling, probably with longjmp
+ *      VAR=value prefix for simple commands
+ *      follow IFS rules more precisely, including update semantics
+ *      write builtin_eval, builtin_ulimit, builtin_umask
+ *      figure out what to do with backslash-newline
+ *      explain why we use signal instead of sigaction
+ *      propagate syntax errors, die on resource errors?
+ *      continuation lines, both explicit and implicit - done?
+ *      memory leak finding and plugging - done?
+ *      more testing, especially quoting rules and redirection
+ *      maybe change map[] to use 2-bit entries
+ *      (eventually) remove all the printf's
+ *      more integration with BusyBox: prompts, cmdedit, applets
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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
+ */
+#include <ctype.h>     /* isalpha, isdigit */
+#include <unistd.h>    /* getpid */
+#include <stdlib.h>    /* getenv, atoi */
+#include <string.h>    /* strchr */
+#include <stdio.h>     /* popen etc. */
+#include <glob.h>      /* glob, of course */
+#include <stdarg.h>    /* va_list */
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>    /* should be pretty obvious */
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+
+/* #include <dmalloc.h> */
+/* #define DEBUG_SHELL */
+
+#ifdef BB_VER
+#include "busybox.h"
+#include "cmdedit.h"
+#else
+/* in place of #include "busybox.h"; much of this is indeed
+ * pasted in from the copy of busybox.h in busybox-0.49pre */
+
+#define xrealloc realloc
+#define applet_name "hush"
+#define shell_main main
+
+extern void *xmalloc(size_t size)
+{
+	void *ptr = malloc(size);
+
+	if (!ptr) {
+		fprintf(stderr, "memory_exhausted\n");
+		exit (EXIT_FAILURE);
+	}
+	return ptr;
+}
+
+extern void usage(const char *usage)
+{
+	fprintf(stderr, "Usage: %s\n", usage);
+	exit(EXIT_FAILURE);
+}
+
+static void verror_msg(const char *s, va_list p)
+{
+	fflush(stdout);
+	fprintf(stderr, "%s: ", applet_name);
+	vfprintf(stderr, s, p);
+	fflush(stderr);
+}
+
+extern void error_msg(const char *s, ...)
+{
+	va_list p;
+
+	va_start(p, s);
+	verror_msg(s, p);
+	va_end(p);
+}
+
+extern void error_msg_and_die(const char *s, ...)
+{
+	va_list p;
+
+	va_start(p, s);
+	verror_msg(s, p);
+	va_end(p);
+	exit(EXIT_FAILURE);
+}
+
+static void vperror_msg(const char *s, va_list p)
+{
+	fflush(stdout);
+	fprintf(stderr, "%s: ", applet_name);
+	if (s && *s) {
+		vfprintf(stderr, s, p);
+		fputs(": ", stderr);
+	}
+	fprintf(stderr, "%s\n", strerror(errno));
+	fflush(stderr);
+}
+
+extern void perror_msg(const char *s, ...)
+{
+	va_list p;
+
+	va_start(p, s);
+	vperror_msg(s, p);
+	va_end(p);
+}
+
+extern void perror_msg_and_die(const char *s, ...)
+{
+	va_list p;
+
+	va_start(p, s);
+	vperror_msg(s, p);
+	va_end(p);
+	exit(EXIT_FAILURE);
+}
+
+FILE *xfopen(const char *path, const char *mode)
+{
+	FILE *fp;
+	if ((fp = fopen(path, mode)) == NULL)
+		perror_msg_and_die(path);
+	return fp;
+}
+#endif  /* of busybox.h replacement */
+
+typedef enum {
+	REDIRECT_INPUT     = 1,
+	REDIRECT_OVERWRITE = 2,
+	REDIRECT_APPEND    = 3,
+	REDIRECT_HEREIS    = 4,
+	REDIRECT_IO        = 5
+} redir_type;
+
+/* The descrip member of this structure is only used to make debugging
+ * output pretty */
+struct {int mode; int default_fd; char *descrip;} redir_table[] = {
+	{ 0,                         0, "()" },
+	{ O_RDONLY,                  0, "<"  },
+	{ O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
+	{ O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
+	{ O_RDONLY,                 -1, "<<" },
+	{ O_RDWR,                    1, "<>" }
+};
+
+typedef enum {
+	PIPE_SEQ = 1,
+	PIPE_AND = 2,
+	PIPE_OR  = 3,
+	PIPE_BG  = 4,
+} pipe_style;
+
+/* might eventually control execution */
+typedef enum {
+	RES_NONE  = 0,
+	RES_IF    = 1,
+	RES_THEN  = 2,
+	RES_ELIF  = 3,
+	RES_ELSE  = 4,
+	RES_FI    = 5,
+	RES_FOR   = 6,
+	RES_WHILE = 7,
+	RES_UNTIL = 8,
+	RES_DO    = 9,
+	RES_DONE  = 10,
+	RES_XXXX  = 11
+} reserved_style;
+#define FLAG_END   (1<<RES_NONE)
+#define FLAG_IF    (1<<RES_IF)
+#define FLAG_THEN  (1<<RES_THEN)
+#define FLAG_ELIF  (1<<RES_ELIF)
+#define FLAG_ELSE  (1<<RES_ELSE)
+#define FLAG_FI    (1<<RES_FI)
+#define FLAG_FOR   (1<<RES_FOR)
+#define FLAG_WHILE (1<<RES_WHILE)
+#define FLAG_UNTIL (1<<RES_UNTIL)
+#define FLAG_DO    (1<<RES_DO)
+#define FLAG_DONE  (1<<RES_DONE)
+#define FLAG_START (1<<RES_XXXX)
+
+/* This holds pointers to the various results of parsing */
+struct p_context {
+	struct child_prog *child;
+	struct pipe *list_head;
+	struct pipe *pipe;
+	struct redir_struct *pending_redirect;
+	reserved_style w;
+	int old_flag;				/* for figuring out valid reserved words */
+	struct p_context *stack;
+	/* How about quoting status? */
+};
+
+struct redir_struct {
+	redir_type type;			/* type of redirection */
+	int fd;						/* file descriptor being redirected */
+	int dup;					/* -1, or file descriptor being duplicated */
+	struct redir_struct *next;	/* pointer to the next redirect in the list */ 
+	glob_t word;				/* *word.gl_pathv is the filename */
+};
+
+struct child_prog {
+	pid_t pid;					/* 0 if exited */
+	char **argv;				/* program name and arguments */
+	struct pipe *group;			/* if non-NULL, first in group or subshell */
+	int subshell;				/* flag, non-zero if group must be forked */
+	struct redir_struct *redirects;	/* I/O redirections */
+	glob_t glob_result;			/* result of parameter globbing */
+	int is_stopped;				/* is the program currently running? */
+	struct pipe *family;		/* pointer back to the child's parent pipe */
+};
+
+struct pipe {
+	int jobid;					/* job number */
+	int num_progs;				/* total number of programs in job */
+	int running_progs;			/* number of programs running */
+	char *text;					/* name of job */
+	char *cmdbuf;				/* buffer various argv's point into */
+	pid_t pgrp;					/* process group ID for the job */
+	struct child_prog *progs;	/* array of commands in pipe */
+	struct pipe *next;			/* to track background commands */
+	int stopped_progs;			/* number of programs alive, but stopped */
+	int job_context;			/* bitmask defining current context */
+	pipe_style followup;		/* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
+	reserved_style r_mode;		/* supports if, for, while, until */
+	struct jobset *job_list;
+};
+
+struct jobset {
+	struct pipe *head;			/* head of list of running jobs */
+	struct pipe *fg;			/* current foreground job */
+};
+
+struct close_me {
+	int fd;
+	struct close_me *next;
+};
+
+/* globals, connect us to the outside world
+ * the first three support $?, $#, and $1 */
+char **global_argv;
+unsigned int global_argc;
+unsigned int last_return_code;
+extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
+ 
+/* Variables we export */
+unsigned int shell_context;  /* Used in cmdedit.c to reset the
+                              * context when someone hits ^C */
+
+/* "globals" within this file */
+static char *ifs=NULL;
+static char map[256];
+static int fake_mode=0;
+static int interactive=0;
+static struct close_me *close_me_head = NULL;
+static char *cwd;
+static struct jobset job_list = { NULL, NULL };
+static unsigned int last_bg_pid=0;
+static char *PS1;
+static char *PS2 = "> ";
+
+#define B_CHUNK (100)
+#define B_NOSPAC 1
+#define MAX_LINE 256       /* for cwd */
+#define MAX_READ 256       /* for builtin_read */
+
+typedef struct {
+	char *data;
+	int length;
+	int maxlen;
+	int quote;
+	int nonnull;
+} o_string;
+#define NULL_O_STRING {NULL,0,0,0,0}
+/* used for initialization:
+	o_string foo = NULL_O_STRING; */
+
+/* I can almost use ordinary FILE *.  Is open_memstream() universally
+ * available?  Where is it documented? */
+struct in_str {
+	const char *p;
+	int __promptme;
+	int promptmode;
+	FILE *file;
+	int (*get) (struct in_str *);
+	int (*peek) (struct in_str *);
+};
+#define b_getch(input) ((input)->get(input))
+#define b_peek(input) ((input)->peek(input))
+
+#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
+
+struct built_in_command {
+	char *cmd;					/* name */
+	char *descr;				/* description */
+	int (*function) (struct child_prog *);	/* function ptr */
+};
+
+/* belongs in busybox.h */
+static inline int max(int a, int b) {
+	return (a>b)?a:b;
+}
+
+/* This should be in utility.c */
+#ifdef DEBUG_SHELL
+static void debug_printf(const char *format, ...)
+{
+	va_list args;
+	va_start(args, format);
+	vfprintf(stderr, format, args);
+	va_end(args);
+}
+#else
+static void debug_printf(const char *format, ...) { }
+#endif
+#define final_printf debug_printf
+
+void __syntax(char *file, int line) {
+	fprintf(stderr,"syntax error %s:%d\n",file,line);
+}
+#define syntax() __syntax(__FILE__, __LINE__)
+
+/* Index of subroutines: */
+/*   function prototypes for builtins */
+static int builtin_cd(struct child_prog *child);
+static int builtin_env(struct child_prog *child);
+static int builtin_exec(struct child_prog *child);
+static int builtin_exit(struct child_prog *child);
+static int builtin_export(struct child_prog *child);
+static int builtin_fg_bg(struct child_prog *child);
+static int builtin_help(struct child_prog *child);
+static int builtin_jobs(struct child_prog *child);
+static int builtin_pwd(struct child_prog *child);
+static int builtin_read(struct child_prog *child);
+static int builtin_shift(struct child_prog *child);
+static int builtin_source(struct child_prog *child);
+static int builtin_ulimit(struct child_prog *child);
+static int builtin_umask(struct child_prog *child);
+static int builtin_unset(struct child_prog *child);
+/*   o_string manipulation: */
+static int b_check_space(o_string *o, int len);
+static int b_addchr(o_string *o, int ch);
+static void b_reset(o_string *o);
+static int b_addqchr(o_string *o, int ch, int quote);
+static int b_adduint(o_string *o, unsigned int i);
+/*  in_str manipulations: */
+static int static_get(struct in_str *i);
+static int static_peek(struct in_str *i);
+static int file_get(struct in_str *i);
+static int file_peek(struct in_str *i);
+static void setup_file_in_str(struct in_str *i, FILE *f);
+static void setup_string_in_str(struct in_str *i, const char *s);
+/*  close_me manipulations: */
+static void mark_open(int fd);
+static void mark_closed(int fd);
+static void close_all();
+/*  "run" the final data structures: */
+static char *indenter(int i);
+static int run_list_test(struct pipe *head, int indent);
+static int run_pipe_test(struct pipe *pi, int indent);
+/*  really run the final data structures: */
+static int setup_redirects(struct child_prog *prog, int squirrel[]);
+static int pipe_wait(struct pipe *pi);
+static int run_list_real(struct pipe *pi);
+static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
+static int run_pipe_real(struct pipe *pi);
+/*   extended glob support: */
+static int globhack(const char *src, int flags, glob_t *pglob);
+static int glob_needed(const char *s);
+static int xglob(o_string *dest, int flags, glob_t *pglob);
+/*   data structure manipulation: */
+static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
+static void initialize_context(struct p_context *ctx);
+static int done_word(o_string *dest, struct p_context *ctx);
+static int done_command(struct p_context *ctx);
+static int done_pipe(struct p_context *ctx, pipe_style type);
+/*   primary string parsing: */
+static int redirect_dup_num(struct in_str *input);
+static int redirect_opt_num(o_string *o);
+static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
+static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
+static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
+static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
+static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
+static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
+/*   setup: */
+static int parse_stream_outer(struct in_str *inp);
+static int parse_string_outer(const char *s);
+static int parse_file_outer(FILE *f);
+
+/* Table of built-in functions.  They can be forked or not, depending on
+ * context: within pipes, they fork.  As simple commands, they do not.
+ * When used in non-forking context, they can change global variables
+ * in the parent shell process.  If forked, of course they can not.
+ * For example, 'unset foo | whatever' will parse and run, but foo will
+ * still be set at the end. */
+static struct built_in_command bltins[] = {
+	{"bg", "Resume a job in the background", builtin_fg_bg},
+	{"cd", "Change working directory", builtin_cd},
+	{"env", "Print all environment variables", builtin_env},
+	{"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
+	{"exit", "Exit from shell()", builtin_exit},
+	{"export", "Set environment variable", builtin_export},
+	{"fg", "Bring job into the foreground", builtin_fg_bg},
+	{"jobs", "Lists the active jobs", builtin_jobs},
+	{"pwd", "Print current directory", builtin_pwd},
+	{"read", "Input environment variable", builtin_read},
+	{"shift", "Shift positional parameters", builtin_shift},
+	{"ulimit","Controls resource limits", builtin_ulimit},
+	{"umask","Sets file creation mask", builtin_umask},
+	{"unset", "Unset environment variable", builtin_unset},
+	{".", "Source-in and run commands in a file", builtin_source},
+	{"help", "List shell built-in commands", builtin_help},
+	{NULL, NULL, NULL}
+};
+
+/* built-in 'cd <path>' handler */
+static int builtin_cd(struct child_prog *child)
+{
+	char *newdir;
+	if (child->argv[1] == NULL)
+		newdir = getenv("HOME");
+	else
+		newdir = child->argv[1];
+	if (chdir(newdir)) {
+		printf("cd: %s: %s\n", newdir, strerror(errno));
+		return EXIT_FAILURE;
+	}
+	getcwd(cwd, sizeof(char)*MAX_LINE);
+	return EXIT_SUCCESS;
+}
+
+/* built-in 'env' handler */
+static int builtin_env(struct child_prog *dummy)
+{
+	char **e = environ;
+	if (e == NULL) return EXIT_FAILURE;
+	for (; *e; e++) {
+		puts(*e);
+	}
+	return EXIT_SUCCESS;
+}
+
+/* built-in 'exec' handler */
+static int builtin_exec(struct child_prog *child)
+{
+	if (child->argv[1] == NULL)
+		return EXIT_SUCCESS;   /* Really? */
+	child->argv++;
+	pseudo_exec(child);
+	/* never returns */
+}
+
+/* built-in 'exit' handler */
+static int builtin_exit(struct child_prog *child)
+{
+	if (child->argv[1] == NULL)
+		exit(EXIT_SUCCESS);
+	exit (atoi(child->argv[1]));
+}
+
+/* built-in 'export VAR=value' handler */
+static int builtin_export(struct child_prog *child)
+{
+	int res;
+
+	if (child->argv[1] == NULL) {
+		return (builtin_env(child));
+	}
+	res = putenv(child->argv[1]);
+	if (res)
+		fprintf(stderr, "export: %s\n", strerror(errno));
+	return (res);
+}
+
+/* built-in 'fg' and 'bg' handler */
+static int builtin_fg_bg(struct child_prog *child)
+{
+	int i, jobNum;
+	struct pipe *job=NULL;
+	
+	if (!child->argv[1] || child->argv[2]) {
+		error_msg("%s: exactly one argument is expected\n",
+				child->argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
+		error_msg("%s: bad argument '%s'\n",
+				child->argv[0], child->argv[1]);
+		return EXIT_FAILURE;
+	}
+
+	for (job = child->family->job_list->head; job; job = job->next) {
+		if (job->jobid == jobNum) {
+			break;
+		}
+	}
+
+	if (!job) {
+		error_msg("%s: unknown job %d\n",
+				child->argv[0], jobNum);
+		return EXIT_FAILURE;
+	}
+
+	if (*child->argv[0] == 'f') {
+		/* Make this job the foreground job */
+		/* suppress messages when run from /linuxrc mag@sysgo.de */
+		if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
+			perror_msg("tcsetpgrp"); 
+		child->family->job_list->fg = job;
+	}
+
+	/* Restart the processes in the job */
+	for (i = 0; i < job->num_progs; i++)
+		job->progs[i].is_stopped = 0;
+
+	kill(-job->pgrp, SIGCONT);
+
+	job->stopped_progs = 0;
+	return EXIT_SUCCESS;
+}
+
+/* built-in 'help' handler */
+static int builtin_help(struct child_prog *dummy)
+{
+	struct built_in_command *x;
+
+	printf("\nBuilt-in commands:\n");
+	printf("-------------------\n");
+	for (x = bltins; x->cmd; x++) {
+		if (x->descr==NULL)
+			continue;
+		printf("%s\t%s\n", x->cmd, x->descr);
+	}
+	printf("\n\n");
+	return EXIT_SUCCESS;
+}
+
+/* built-in 'jobs' handler */
+static int builtin_jobs(struct child_prog *child)
+{
+	struct pipe *job;
+	char *status_string;
+
+	for (job = child->family->job_list->head; job; job = job->next) {
+		if (job->running_progs == job->stopped_progs)
+			status_string = "Stopped";
+		else
+			status_string = "Running";
+		printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
+	}
+	return EXIT_SUCCESS;
+}
+
+
+/* built-in 'pwd' handler */
+static int builtin_pwd(struct child_prog *dummy)
+{
+	getcwd(cwd, MAX_LINE);
+	puts(cwd);
+	return EXIT_SUCCESS;
+}
+
+/* built-in 'read VAR' handler */
+static int builtin_read(struct child_prog *child)
+{
+	int res = 0, len, newlen;
+	char *s;
+	char string[MAX_READ];
+
+	if (child->argv[1]) {
+		/* argument (VAR) given: put "VAR=" into buffer */
+		strcpy(string, child->argv[1]);
+		len = strlen(string);
+		string[len++] = '=';
+		string[len]   = '\0';
+		/* XXX would it be better to go through in_str? */
+		fgets(&string[len], sizeof(string) - len, stdin);	/* read string */
+		newlen = strlen(string);
+		if(newlen > len)
+			string[--newlen] = '\0';	/* chomp trailing newline */
+		/*
+		** string should now contain "VAR=<value>"
+		** copy it (putenv() won't do that, so we must make sure
+		** the string resides in a static buffer!)
+		*/
+		res = -1;
+		if((s = strdup(string)))
+			res = putenv(s);
+		if (res)
+			fprintf(stderr, "read: %s\n", strerror(errno));
+	}
+	else
+		fgets(string, sizeof(string), stdin);
+
+	return (res);
+}
+
+/* Built-in 'shift' handler */
+static int builtin_shift(struct child_prog *child)
+{
+	int n=1;
+	if (child->argv[1]) {
+		n=atoi(child->argv[1]);
+	}
+	if (n>=0 && n<global_argc) {
+		/* XXX This probably breaks $0 */
+		global_argc -= n;
+		global_argv += n;
+		return EXIT_SUCCESS;
+	} else {
+		return EXIT_FAILURE;
+	}
+}
+
+/* Built-in '.' handler (read-in and execute commands from file) */
+static int builtin_source(struct child_prog *child)
+{
+	FILE *input;
+	int status;
+
+	if (child->argv[1] == NULL)
+		return EXIT_FAILURE;
+
+	/* XXX search through $PATH is missing */
+	input = fopen(child->argv[1], "r");
+	if (!input) {
+		fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]);
+		return EXIT_FAILURE;
+	}
+
+	/* Now run the file */
+	/* XXX argv and argc are broken; need to save old global_argv
+	 * (pointer only is OK!) on this stack frame,
+	 * set global_argv=child->argv+1, recurse, and restore. */
+	mark_open(fileno(input));
+	status = parse_file_outer(input);
+	mark_closed(fileno(input));
+	fclose(input);
+	return (status);
+}
+
+static int builtin_ulimit(struct child_prog *child)
+{
+	printf("builtin_ulimit not written\n");
+	return EXIT_FAILURE;
+}
+
+static int builtin_umask(struct child_prog *child)
+{
+	printf("builtin_umask not written\n");
+	return EXIT_FAILURE;
+}
+
+/* built-in 'unset VAR' handler */
+static int builtin_unset(struct child_prog *child)
+{
+	if (child->argv[1] == NULL) {
+		fprintf(stderr, "unset: parameter required.\n");
+		return EXIT_FAILURE;
+	}
+	unsetenv(child->argv[1]);
+	return EXIT_SUCCESS;
+}
+
+static int b_check_space(o_string *o, int len)
+{
+	/* It would be easy to drop a more restrictive policy
+	 * in here, such as setting a maximum string length */
+	if (o->length + len > o->maxlen) {
+		char *old_data = o->data;
+		/* assert (data == NULL || o->maxlen != 0); */
+		o->maxlen += max(2*len, B_CHUNK);
+		o->data = realloc(o->data, 1 + o->maxlen);
+		if (o->data == NULL) {
+			free(old_data);
+		}
+	}
+	return o->data == NULL;
+}
+
+static int b_addchr(o_string *o, int ch)
+{
+	debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
+	if (b_check_space(o, 1)) return B_NOSPAC;
+	o->data[o->length] = ch;
+	o->length++;
+	o->data[o->length] = '\0';
+	return 0;
+}
+
+static void b_reset(o_string *o)
+{
+	o->length = 0;
+	o->nonnull = 0;
+	if (o->data != NULL) *o->data = '\0';
+}
+
+static void b_free(o_string *o)
+{
+	b_reset(o);
+	if (o->data != NULL) free(o->data);
+	o->data = NULL;
+	o->maxlen = 0;
+}
+
+/* My analysis of quoting semantics tells me that state information
+ * is associated with a destination, not a source.
+ */
+static int b_addqchr(o_string *o, int ch, int quote)
+{
+	if (quote && strchr("*?[\\",ch)) {
+		int rc;
+		rc = b_addchr(o, '\\');
+		if (rc) return rc;
+	}
+	return b_addchr(o, ch);
+}
+
+/* belongs in utility.c */
+char *simple_itoa(unsigned int i)
+{
+	/* 21 digits plus null terminator, good for 64-bit or smaller ints */
+	static char local[22];
+	char *p = &local[21];
+	*p-- = '\0';
+	do {
+		*p-- = '0' + i % 10;
+		i /= 10;
+	} while (i > 0);
+	return p + 1;
+}
+
+static int b_adduint(o_string *o, unsigned int i)
+{
+	int r;
+	char *p = simple_itoa(i);
+	/* no escape checking necessary */
+	do r=b_addchr(o, *p++); while (r==0 && *p);
+	return r;
+}
+
+static int static_get(struct in_str *i)
+{
+	int ch=*i->p++;
+	if (ch=='\0') return EOF;
+	return ch;
+}
+
+static int static_peek(struct in_str *i)
+{
+	return *i->p;
+}
+
+static inline void cmdedit_set_initial_prompt(void)
+{
+#ifdef BB_FEATURE_SH_SIMPLE_PROMPT
+	PS1 = NULL;
+#else
+	PS1 = getenv("PS1");
+	if(PS1==0)
+		PS1 = "\\w \\$ ";
+#endif	
+}
+
+static inline void setup_prompt_string(int promptmode, char **prompt_str)
+{
+#ifdef BB_FEATURE_SH_SIMPLE_PROMPT
+	/* Set up the prompt */
+	if (promptmode == 1) {
+		if (PS1)
+			free(PS1);
+		PS1=xmalloc(strlen(cwd)+4);
+		sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
+		*prompt_str = PS1;
+	} else {
+		*prompt_str = PS2;
+	}
+#else
+	*prompt_str = (promptmode==0)? PS1 : PS2;
+#endif	
+}
+
+static void get_user_input(struct in_str *i)
+{
+	char *prompt_str;
+	static char the_command[MAX_LINE];
+
+	setup_prompt_string(i->promptmode, &prompt_str);
+#ifdef BB_FEATURE_COMMAND_EDITING
+	/*
+	 ** enable command line editing only while a command line
+	 ** is actually being read; otherwise, we'll end up bequeathing
+	 ** atexit() handlers and other unwanted stuff to our
+	 ** child processes (rob@sysgo.de)
+	 */
+	cmdedit_read_input(prompt_str, the_command);
+	cmdedit_terminate();
+#else
+	fputs(prompt_str, stdout);
+	fflush(stdout);
+	the_command[0]=fgetc(i->file);
+	the_command[1]='\0';
+#endif
+	i->p = the_command;
+}
+
+/* This is the magic location that prints prompts 
+ * and gets data back from the user */
+static int file_get(struct in_str *i)
+{
+	int ch;
+
+	ch = 0;
+	/* If there is data waiting, eat it up */
+	if (i->p && *i->p) {
+		ch=*i->p++;
+	} else {
+		/* need to double check i->file because we might be doing something
+		 * more complicated by now, like sourcing or substituting. */
+		if (i->__promptme && interactive && i->file == stdin) {
+			get_user_input(i);
+			i->promptmode=2;
+		}
+		i->__promptme = 0;
+
+		if (i->p && *i->p) {
+			ch=*i->p++;
+		}
+		debug_printf("b_getch: got a %d\n", ch);
+	}
+	if (ch == '\n') i->__promptme=1;
+	return ch;
+}
+
+/* All the callers guarantee this routine will never be
+ * used right after a newline, so prompting is not needed.
+ */
+static int file_peek(struct in_str *i)
+{
+	if (i->p && *i->p) {
+		return *i->p;
+	} else {
+		static char buffer;
+		buffer = fgetc(i->file);
+		i->p = &buffer;
+		debug_printf("b_peek: got a %d\n", *i->p);
+		return *i->p; 
+	}
+}
+
+static void setup_file_in_str(struct in_str *i, FILE *f)
+{
+	i->peek = file_peek;
+	i->get = file_get;
+	i->__promptme=1;
+	i->promptmode=1;
+	i->file = f;
+	i->p = NULL;
+}
+
+static void setup_string_in_str(struct in_str *i, const char *s)
+{
+	i->peek = static_peek;
+	i->get = static_get;
+	i->__promptme=1;
+	i->promptmode=1;
+	i->p = s;
+}
+
+static void mark_open(int fd)
+{
+	struct close_me *new = xmalloc(sizeof(struct close_me));
+	new->fd = fd;
+	new->next = close_me_head;
+	close_me_head = new;
+}
+
+static void mark_closed(int fd)
+{
+	struct close_me *tmp;
+	if (close_me_head == NULL || close_me_head->fd != fd)
+		error_msg_and_die("corrupt close_me");
+	tmp = close_me_head;
+	close_me_head = close_me_head->next;
+	free(tmp);
+}
+
+static void close_all()
+{
+	struct close_me *c;
+	for (c=close_me_head; c; c=c->next) {
+		close(c->fd);
+	}
+	close_me_head = NULL;
+}
+
+/* squirrel != NULL means we squirrel away copies of stdin, stdout,
+ * and stderr if they are redirected. */
+static int setup_redirects(struct child_prog *prog, int squirrel[])
+{
+	int openfd, mode;
+	struct redir_struct *redir;
+
+	for (redir=prog->redirects; redir; redir=redir->next) {
+		if (redir->dup == -1) {
+			mode=redir_table[redir->type].mode;
+			openfd = open(redir->word.gl_pathv[0], mode, 0666);
+			if (openfd < 0) {
+			/* this could get lost if stderr has been redirected, but
+			   bash and ash both lose it as well (though zsh doesn't!) */
+				fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0],
+					strerror(errno));
+				return 1;
+			}
+		} else {
+			openfd = redir->dup;
+		}
+
+		if (openfd != redir->fd) {
+			if (squirrel && redir->fd < 3) {
+				squirrel[redir->fd] = dup(redir->fd);
+			}
+			dup2(openfd, redir->fd);
+			close(openfd);
+		}
+	}
+	return 0;
+}
+
+static void restore_redirects(int squirrel[])
+{
+	int i, fd;
+	for (i=0; i<3; i++) {
+		fd = squirrel[i];
+		if (fd != -1) {
+			/* No error checking.  I sure wouldn't know what
+			 * to do with an error if I found one! */
+			dup2(fd, i);
+			close(fd);
+		}
+	}
+}
+
+/* XXX this definitely needs some more thought, work, and
+ * cribbing from other shells */
+static int pipe_wait(struct pipe *pi)
+{
+	int rcode=0, i, pid, running, status;
+	running = pi->num_progs;
+	while (running) {
+		pid=waitpid(-1, &status, 0);
+		if (pid < 0) perror_msg_and_die("waitpid");
+		for (i=0; i < pi->num_progs; i++) {
+			if (pi->progs[i].pid == pid) {
+				if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
+				pi->progs[i].pid = 0;
+				running--;
+				break;
+			}
+		}
+	}
+	return rcode;
+}
+
+/* very simple version for testing */
+static void pseudo_exec(struct child_prog *child)
+{
+	int rcode;
+	struct built_in_command *x;
+	if (child->argv) {
+		/*
+		 * Check if the command matches any of the builtins.
+		 * Depending on context, this might be redundant.  But it's
+		 * easier to waste a few CPU cycles than it is to figure out
+		 * if this is one of those cases.
+		 */
+		for (x = bltins; x->cmd; x++) {
+			if (strcmp(child->argv[0], x->cmd) == 0 ) {
+				debug_printf("builtin exec %s\n", child->argv[0]);
+				exit(x->function(child));
+			}
+		}
+		debug_printf("exec of %s\n",child->argv[0]);
+		execvp(child->argv[0],child->argv);
+		perror("execvp");
+		exit(1);
+	} else if (child->group) {
+		debug_printf("runtime nesting to group\n");
+		interactive=0;    /* crucial!!!! */
+		rcode = run_list_real(child->group);
+		/* OK to leak memory by not calling run_list_test,
+		 * since this process is about to exit */
+		exit(rcode);
+	} else {
+		/* Can happen.  See what bash does with ">foo" by itself. */
+		debug_printf("trying to pseudo_exec null command\n");
+		exit(EXIT_SUCCESS);
+	}
+}
+
+/* run_pipe_real() starts all the jobs, but doesn't wait for anything
+ * to finish.  See pipe_wait().
+ *
+ * return code is normally -1, when the caller has to wait for children
+ * to finish to determine the exit status of the pipe.  If the pipe
+ * is a simple builtin command, however, the action is done by the
+ * time run_pipe_real returns, and the exit code is provided as the
+ * return value.
+ *
+ * The input of the pipe is always stdin, the output is always
+ * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
+ * because it tries to avoid running the command substitution in
+ * subshell, when that is in fact necessary.  The subshell process
+ * now has its stdout directed to the input of the appropriate pipe,
+ * so this routine is noticeably simpler.
+ */
+static int run_pipe_real(struct pipe *pi)
+{
+	int i;
+	int nextin, nextout;
+	int pipefds[2];				/* pipefds[0] is for reading */
+	struct child_prog *child;
+	struct built_in_command *x;
+
+	nextin = 0;
+	pi->pgrp = 0;
+
+	/* Check if this is a simple builtin (not part of a pipe).
+	 * Builtins within pipes have to fork anyway, and are handled in
+	 * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
+	 */
+	if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
+		child = & (pi->progs[0]);
+		if (child->group && ! child->subshell) {
+			int squirrel[] = {-1, -1, -1};
+			int rcode;
+			debug_printf("non-subshell grouping\n");
+			setup_redirects(child, squirrel);
+			/* XXX could we merge code with following builtin case,
+			 * by creating a pseudo builtin that calls run_list_real? */
+			rcode = run_list_real(child->group);
+			restore_redirects(squirrel);
+			return rcode;
+		}
+		for (x = bltins; x->cmd; x++) {
+			if (strcmp(child->argv[0], x->cmd) == 0 ) {
+				int squirrel[] = {-1, -1, -1};
+				int rcode;
+				debug_printf("builtin inline %s\n", child->argv[0]);
+				/* XXX setup_redirects acts on file descriptors, not FILEs.
+				 * This is perfect for work that comes after exec().
+				 * Is it really safe for inline use?  Experimentally,
+				 * things seem to work with glibc. */
+				setup_redirects(child, squirrel);
+				rcode = x->function(child);
+				restore_redirects(squirrel);
+				return rcode;
+			}
+		}
+	}
+
+	for (i = 0; i < pi->num_progs; i++) {
+		child = & (pi->progs[i]);
+
+		/* pipes are inserted between pairs of commands */
+		if ((i + 1) < pi->num_progs) {
+			if (pipe(pipefds)<0) perror_msg_and_die("pipe");
+			nextout = pipefds[1];
+		} else {
+			nextout=1;
+			pipefds[0] = -1;
+		}
+
+		/* XXX test for failed fork()? */
+		if (!(child->pid = fork())) {
+			close_all();
+
+			if (nextin != 0) {
+				dup2(nextin, 0);
+				close(nextin);
+			}
+			if (nextout != 1) {
+				dup2(nextout, 1);
+				close(nextout);
+			}
+			if (pipefds[0]!=-1) {
+				close(pipefds[0]);  /* opposite end of our output pipe */
+			}
+
+			/* Like bash, explicit redirects override pipes,
+			 * and the pipe fd is available for dup'ing. */
+			setup_redirects(child,NULL);
+
+			pseudo_exec(child);
+		}
+		if (interactive) {
+			/* Put our child in the process group whose leader is the
+			 * first process in this pipe. */
+			if (pi->pgrp==0) {
+				pi->pgrp = child->pid;
+			}
+			/* Don't check for errors.  The child may be dead already,
+			 * in which case setpgid returns error code EACCES. */
+			setpgid(child->pid, pi->pgrp);
+		}
+		/* In the non-interactive case, do nothing.  Leave the children
+		 * with the process group that they inherited from us. */
+	
+		if (nextin != 0)
+			close(nextin);
+		if (nextout != 1)
+			close(nextout);
+
+		/* If there isn't another process, nextin is garbage 
+		   but it doesn't matter */
+		nextin = pipefds[0];
+	}
+	return -1;
+}
+
+static int run_list_real(struct pipe *pi)
+{
+	int rcode=0;
+	int if_code=0, next_if_code=0;  /* need double-buffer to handle elif */
+	reserved_style rmode=RES_NONE;
+	for (;pi;pi=pi->next) {
+		rmode = pi->r_mode;
+		debug_printf("rmode=%d  if_code=%d  next_if_code=%d\n", rmode, if_code, next_if_code);
+		if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
+		if (rmode == RES_THEN &&  if_code) continue;
+		if (rmode == RES_ELSE && !if_code) continue;
+		if (rmode == RES_ELIF && !if_code) continue;
+		if (pi->num_progs == 0) break;
+		rcode = run_pipe_real(pi);
+		if (rcode!=-1) {
+			/* We only ran a builtin: rcode was set by the return value
+			 * of run_pipe_real(), and we don't need to wait for anything. */
+		} else if (pi->followup==PIPE_BG) {
+			/* XXX check bash's behavior with nontrivial pipes */
+			/* XXX compute jobid */
+			/* XXX what does bash do with attempts to background builtins? */
+			printf("[%d] %d\n", pi->jobid, pi->pgrp);
+			last_bg_pid = pi->pgrp;
+			rcode = EXIT_SUCCESS;
+		} else {
+			if (interactive) {
+				/* move the new process group into the foreground */
+				/* suppress messages when run from /linuxrc mag@sysgo.de */
+				signal(SIGTTIN, SIG_IGN);
+				signal(SIGTTOU, SIG_IGN);
+				if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
+					perror_msg("tcsetpgrp");
+				rcode = pipe_wait(pi);
+				if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
+					perror_msg("tcsetpgrp");
+				signal(SIGTTIN, SIG_DFL);
+				signal(SIGTTOU, SIG_DFL);
+			} else {
+				rcode = pipe_wait(pi);
+			}
+		}
+		last_return_code=rcode;
+		if ( rmode == RES_IF || rmode == RES_ELIF )
+			next_if_code=rcode;  /* can be overwritten a number of times */
+		if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
+		     (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
+			return rcode;  /* XXX broken if list is part of if/then/else */
+	}
+	return rcode;
+}
+
+/* broken, of course, but OK for testing */
+static char *indenter(int i)
+{
+	static char blanks[]="                                    ";
+	return &blanks[sizeof(blanks)-i-1];
+}
+
+/* return code is the exit status of the pipe */
+static int run_pipe_test(struct pipe *pi, int indent)
+{
+	char **p;
+	struct child_prog *child;
+	struct redir_struct *r, *rnext;
+	int a, i, ret_code=0;
+	char *ind = indenter(indent);
+	final_printf("%s run pipe: (pid %d)\n",ind,getpid());
+	for (i=0; i<pi->num_progs; i++) {
+		child = &pi->progs[i];
+		final_printf("%s  command %d:\n",ind,i);
+		if (child->argv) {
+			for (a=0,p=child->argv; *p; a++,p++) {
+				final_printf("%s   argv[%d] = %s\n",ind,a,*p);
+			}
+			globfree(&child->glob_result);
+			child->argv=NULL;
+		} else if (child->group) {
+			final_printf("%s   begin group (subshell:%d)\n",ind, child->subshell);
+			ret_code = run_list_test(child->group,indent+3);
+			final_printf("%s   end group\n",ind);
+		} else {
+			final_printf("%s   (nil)\n",ind);
+		}
+		for (r=child->redirects; r; r=rnext) {
+			final_printf("%s   redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
+			if (r->dup == -1) {
+				final_printf(" %s\n", *r->word.gl_pathv);
+				globfree(&r->word);
+			} else {
+				final_printf("&%d\n", r->dup);
+			}
+			rnext=r->next;
+			free(r);
+		}
+		child->redirects=NULL;
+	}
+	free(pi->progs);   /* children are an array, they get freed all at once */
+	pi->progs=NULL;
+	return ret_code;
+}
+
+static int run_list_test(struct pipe *head, int indent)
+{
+	int rcode=0;   /* if list has no members */
+	struct pipe *pi, *next;
+	char *ind = indenter(indent);
+	for (pi=head; pi; pi=next) {
+		if (pi->num_progs == 0) break;
+		final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
+		rcode = run_pipe_test(pi, indent);
+		final_printf("%s pipe followup code %d\n", ind, pi->followup);
+		next=pi->next;
+		pi->next=NULL;
+		free(pi);
+	}
+	return rcode;	
+}
+
+/* Select which version we will use */
+static int run_list(struct pipe *pi)
+{
+	int rcode=0;
+	if (fake_mode==0) {
+		rcode = run_list_real(pi);
+	} 
+	/* run_list_test 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. */
+	run_list_test(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.
+ */
+static int globhack(const char *src, int flags, glob_t *pglob)
+{
+	int cnt, pathc;
+	const char *s;
+	char *dest;
+	for (cnt=1, s=src; *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++, 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) {
+		fprintf(stderr,"out of memory during glob\n");
+		exit(1);
+	}
+	if (gr != 0) { /* GLOB_ABORTED ? */
+		fprintf(stderr,"glob(3) error %d\n",gr);
+	}
+	/* globprint(glob_target); */
+	return gr;
+}
+
+/* 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;
+	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" */
+		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;
+}
+
+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 */
+	return pi;
+}
+
+static void initialize_context(struct p_context *ctx)
+{
+	ctx->pipe=NULL;
+	ctx->pending_redirect=NULL;
+	ctx->child=NULL;
+	ctx->list_head=new_pipe();
+	ctx->pipe=ctx->list_head;
+	ctx->w=RES_NONE;
+	ctx->stack=NULL;
+	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.
+ */
+int reserved_word(o_string *dest, struct p_context *ctx)
+{
+	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_DO   | FLAG_START },
+		{ "while", RES_WHILE, FLAG_DO   | FLAG_START },
+		{ "until", RES_UNTIL, FLAG_DO   | FLAG_START },
+		{ "do",    RES_DO,    FLAG_DONE },
+		{ "done",  RES_DONE,  FLAG_END  }
+	};
+	struct reserved_combo *r;
+	for (r=reserved_list;
+#define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
+		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");
+				*new = *ctx;   /* physical copy */
+				initialize_context(ctx);
+				ctx->stack=new;
+			} else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
+				syntax();  /* XXX how do we get out? */
+			}
+			ctx->w=r->code;
+			ctx->old_flag = r->flag;
+			if (ctx->old_flag & FLAG_END) {
+				struct p_context *old;
+				debug_printf("pop stack\n");
+				old = ctx->stack;
+				old->child->group = ctx->list_head;
+				*ctx = *old;   /* physical copy */
+				free(old);
+				ctx->w=RES_NONE;
+			}
+			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;
+	glob_t *glob_target;
+	int gr, flags = 0;
+
+	debug_printf("done_word: %s %p\n", dest->data, child);
+	if (dest->length == 0 && !dest->nonnull) {
+		debug_printf("  true null, ignored\n");
+		return 0;
+	}
+	if (ctx->pending_redirect) {
+		glob_target = &ctx->pending_redirect->word;
+	} else {
+		if (child->group) {
+			syntax();
+			return 1;  /* syntax error, groups and arglists don't mix */
+		}
+		if (!child->argv) {
+			debug_printf("checking %s for reserved-ness\n",dest->data);
+			if (reserved_word(dest,ctx)) return 0;
+		}
+		glob_target = &child->glob_result;
+ 		if (child->argv) flags |= GLOB_APPEND;
+	}
+	gr = xglob(dest, flags, glob_target);
+	if (gr != 0) return 1;
+
+	b_reset(dest);
+	if (ctx->pending_redirect) {
+		ctx->pending_redirect=NULL;
+		if (glob_target->gl_pathc != 1) {
+			fprintf(stderr, "ambiguous redirect\n");
+			return 1;
+		}
+	} else {
+		child->argv = glob_target->gl_pathv;
+	}
+	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
+	         && prog->redirects == NULL) {
+		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;
+	prog->redirects = NULL;
+	prog->argv = NULL;
+	prog->is_stopped = 0;
+	prog->group = NULL;
+	prog->glob_result.gl_pathv = NULL;
+	prog->family = pi;
+
+	ctx->child=prog;
+	/* 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;
+}
+
+/* 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 & */
+	while (ch=b_peek(input),isdigit(ch)) {
+		d = d*10+(ch-'0');
+		ok=1;
+		b_getch(input);
+	}
+	if (ok) return d;
+
+	fprintf(stderr, "ambiguous redirect\n");
+	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
+	run_list_test(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);
+	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 */
+}
+
+/* basically useful version until someone wants to get fancier,
+ * see the bash man page under "Parameter Expansion" */
+static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
+{
+	const char *p=NULL;
+	if (src->data) p = getenv(src->data);
+	if (p) parse_string(dest, ctx, p);   /* recursion */
+	b_free(src);
+}
+
+/* return code: 0 for OK, 1 for syntax error */
+static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
+{
+	int i, advance=0;
+	o_string alt=NULL_O_STRING;
+	char sep[]=" ";
+	int ch = input->peek(input);  /* first character after the $ */
+	debug_printf("handle_dollar: ch=%c\n",ch);
+	if (isalpha(ch)) {
+		while(ch=b_peek(input),isalnum(ch) || ch=='_') {
+			b_getch(input);
+			b_addchr(&alt,ch);
+		}
+		lookup_param(dest, ctx, &alt);
+	} else if (isdigit(ch)) {
+		i = ch-'0';  /* XXX is $0 special? */
+		if (i<global_argc) {
+			parse_string(dest, ctx, global_argv[i]); /* recursion */
+		}
+		advance = 1;
+	} else switch (ch) {
+		case '$':
+			b_adduint(dest,getpid());
+			advance = 1;
+			break;
+		case '!':
+			if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
+			advance = 1;
+			break;
+		case '?':
+			b_adduint(dest,last_return_code);
+			advance = 1;
+			break;
+		case '#':
+			b_adduint(dest,global_argc ? global_argc-1 : 0);
+			advance = 1;
+			break;
+		case '{':
+			b_getch(input);
+			/* XXX maybe someone will try to escape the '}' */
+			while(ch=b_getch(input),ch!=EOF && ch!='}') {
+				b_addchr(&alt,ch);
+			}
+			if (ch != '}') {
+				syntax();
+				return 1;
+			}
+			lookup_param(dest, ctx, &alt);
+			break;
+		case '(':
+			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 */
+			fprintf(stderr,"unhandled syntax: $%c\n",ch);
+			return 1;
+			break;
+		default:
+			b_addqchr(dest,'$',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;
+}
+
+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');
+}
+
+/* return code is 0 for normal exit, 1 for syntax error */
+int parse_stream(o_string *dest, struct p_context *ctx,
+	struct in_str *input, int end_trigger)
+{
+	unsigned int ch, m;
+	int redir_fd;
+	redir_type redir_style;
+	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];
+		next = (ch == '\n') ? 0 : b_peek(input);
+		debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
+			ch,ch,m,dest->quote);
+		if (m==0 || ((m==1 || m==2) && dest->quote)) {
+			b_addqchr(dest, ch, dest->quote);
+		} else if (ch == end_trigger && !dest->quote) {
+			debug_printf("leaving parse_stream\n");
+			return 0;
+		} else if (m==2 && !dest->quote) {  /* IFS */
+			done_word(dest, ctx);
+#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
+		} else 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!='\'') {
+				b_addchr(dest,ch);
+			}
+			if (ch==EOF) {
+				syntax();
+				return 1;
+			}
+			break;
+		case '"':
+			dest->nonnull = 1;
+			dest->quote = !dest->quote;
+			break;
+		case '`':
+			process_command_subs(dest, ctx, input, '`');
+			break;
+		case '>':
+			redir_fd = redirect_opt_num(dest);
+			done_word(dest, ctx);
+			redir_style=REDIRECT_OVERWRITE;
+			if (next == '>') {
+				redir_style=REDIRECT_APPEND;
+				b_getch(input);
+			} else if (next == '(') {
+				syntax();   /* until we support >(list) Process Substitution */
+				return 1;
+			}
+			setup_redirect(ctx, redir_fd, redir_style, input);
+			break;
+		case '<':
+			redir_fd = redirect_opt_num(dest);
+			done_word(dest, ctx);
+			redir_style=REDIRECT_INPUT;
+			if (next == '<') {
+				redir_style=REDIRECT_HEREIS;
+				b_getch(input);
+			} else if (next == '>') {
+				redir_style=REDIRECT_IO;
+				b_getch(input);
+			} else if (next == '(') {
+				syntax();   /* until we support <(list) Process Substitution */
+				return 1;
+			}
+			setup_redirect(ctx, redir_fd, redir_style, input);
+			break;
+		case ';':
+			done_word(dest, ctx);
+			done_pipe(ctx,PIPE_SEQ);
+			break;
+		case '&':
+			done_word(dest, ctx);
+			if (next=='&') {
+				b_getch(input);
+				done_pipe(ctx,PIPE_AND);
+			} else {
+				done_pipe(ctx,PIPE_BG);
+			}
+			break;
+		case '|':
+			done_word(dest, ctx);
+			if (next=='|') {
+				b_getch(input);
+				done_pipe(ctx,PIPE_OR);
+			} else {
+				/* we could pick up a file descriptor choice here
+				 * with redirect_opt_num(), but bash doesn't do it.
+				 * "echo foo 2| cat" yields "foo 2". */
+				done_command(ctx);
+			}
+			break;
+		case '(':
+		case '{':
+			if (parse_group(dest, ctx, input, ch)!=0) return 1;
+			break;
+		case ')':
+		case '}':
+			syntax();   /* Proper use of this character caught by end_trigger */
+			return 1;
+			break;
+		default:
+			syntax();   /* this is really an internal logic error */
+			return 1;
+		}
+	}
+	/* complain if quote?  No, maybe we just finished a command substitution
+	 * that was quoted.  Example:
+	 * $ echo "`cat foo` plus more" 
+	 * and we just got the EOF generated by the subshell that ran "cat foo"
+	 * The only real complaint is if we got an EOF when end_trigger != '\0',
+	 * that is, we were really supposed to get end_trigger, and never got
+	 * one before the EOF.  Can't use the standard "syntax error" return code,
+	 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
+	if (end_trigger != '\0') return -1;
+	return 0;
+}
+
+void mapset(const unsigned char *set, int code)
+{
+	const unsigned char *s;
+	for (s=set; *s; s++) map[*s] = code;
+}
+
+void update_ifs_map(void)
+{
+	/* char *ifs and char map[256] are both globals. */
+	ifs = getenv("IFS");
+	if (ifs == NULL) ifs=" \t\n";
+	/* Precompute a list of 'flow through' behavior so it can be treated
+	 * quickly up front.  Computation is necessary because of IFS.
+	 * Special case handling of IFS == " \t\n" is not implemented.
+	 * The map[] array only really needs two bits each, and on most machines
+	 * that would be faster because of the reduced L1 cache footprint.
+	 */
+	memset(map,0,256);        /* most characters flow through always */
+	mapset("\\$'\"`", 3);     /* never flow through */
+	mapset("<>;&|(){}#", 1);  /* flow through if quoted */
+	mapset(ifs, 2);           /* also flow through if quoted */
+}
+
+/* most recursion does not come through here, the exeception is
+ * from builtin_source() */
+int parse_stream_outer(struct in_str *inp)
+{
+
+	struct p_context ctx;
+	o_string temp=NULL_O_STRING;
+	int rcode;
+	do {
+		initialize_context(&ctx);
+		update_ifs_map();
+		inp->promptmode=1;
+		rcode = parse_stream(&temp, &ctx, inp, '\n');
+		done_word(&temp, &ctx);
+		done_pipe(&ctx,PIPE_SEQ);
+		run_list(ctx.list_head);
+	} while (rcode != -1);   /* loop on syntax errors, return on EOF */
+	return 0;
+}
+
+static int parse_string_outer(const char *s)
+{
+	struct in_str input;
+	setup_string_in_str(&input, s);
+	return parse_stream_outer(&input);
+}
+
+static int parse_file_outer(FILE *f)
+{
+	int rcode;
+	struct in_str input;
+	setup_file_in_str(&input, f);
+	rcode = parse_stream_outer(&input);
+	return rcode;
+}
+
+int shell_main(int argc, char **argv)
+{
+	int opt;
+	FILE *input;
+
+	/* XXX what should these be while sourcing /etc/profile? */
+	global_argc = argc;
+	global_argv = argv;
+
+	if (argv[0] && argv[0][0] == '-') {
+		debug_printf("\nsourcing /etc/profile\n");
+		input = xfopen("/etc/profile", "r");
+		mark_open(fileno(input));
+		parse_file_outer(input);
+		mark_closed(fileno(input));
+		fclose(input);
+	}
+	input=stdin;
+	
+	/* initialize the cwd -- this is never freed...*/
+	cwd = xgetcwd(0);
+#ifdef BB_FEATURE_COMMAND_EDITING
+	cmdedit_set_initial_prompt();
+#else
+	PS1 = NULL;
+#endif
+	
+	while ((opt = getopt(argc, argv, "c:xif")) > 0) {
+		switch (opt) {
+			case 'c':
+				{
+					global_argv = argv+optind;
+					global_argc = argc-optind;
+					opt = parse_string_outer(optarg);
+					exit(opt);
+				}
+				break;
+			case 'i':
+				interactive++;
+				break;
+			case 'f':
+				fake_mode++;
+				break;
+			default:
+				fprintf(stderr, "Usage: sh [FILE]...\n"
+						"   or: sh -c command [args]...\n\n");
+				exit(EXIT_FAILURE);
+		}
+	}
+	/* A shell is interactive if the `-i' flag was given, or if all of
+	 * the following conditions are met:
+	 *	  no -c command
+	 *    no arguments remaining or the -s flag given
+	 *    standard input is a terminal
+	 *    standard output is a terminal
+	 *    Refer to Posix.2, the description of the `sh' utility. */
+	if (argv[optind]==NULL && input==stdin &&
+			isatty(fileno(stdin)) && isatty(fileno(stdout))) {
+		interactive++;
+	}
+	
+	if (interactive) {
+		/* Looks like they want an interactive shell */
+		fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
+		exit(parse_file_outer(stdin));
+	}
+	debug_printf("\ninteractive=%d\n", interactive);
+
+	debug_printf("\nrunning script '%s'\n", argv[optind]);
+	global_argv = argv+optind;
+	global_argc = argc-optind;
+	input = xfopen(argv[optind], "r");
+	opt = parse_file_outer(input);
+
+#ifdef BB_FEATURE_CLEAN_UP
+	fclose(input.file);
+#endif
+
+	return(opt);
+}