shell/msh.c

/* vi: set sw=4 ts=4: */
/*
 * Minix shell port for busybox
 *
 * This version of the Minix shell was adapted for use in busybox
 * by Erik Andersen <andersen@codepoet.org>
 *
 * - backtick expansion did not work properly
 *   Jonas Holmberg <jonas.holmberg@axis.com>
 *   Robert Schwebel <r.schwebel@pengutronix.de>
 *   Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include <sys/times.h>
#include <setjmp.h>

#ifdef STANDALONE
# ifndef _GNU_SOURCE
#  define _GNU_SOURCE
# endif
# include <sys/types.h>
# include <sys/stat.h>
# include <sys/wait.h>
# include <signal.h>
# include <stdio.h>
# include <stdlib.h>
# include <unistd.h>
# include <string.h>
# include <errno.h>
# include <dirent.h>
# include <fcntl.h>
# include <ctype.h>
# include <assert.h>
# define bb_dev_null "/dev/null"
# define DEFAULT_SHELL "/proc/self/exe"
# define CONFIG_BUSYBOX_EXEC_PATH "/proc/self/exe"
# define bb_banner "busybox standalone"
# define ENABLE_FEATURE_SH_STANDALONE 0
# define bb_msg_memory_exhausted "memory exhausted"
# define xmalloc(size) malloc(size)
# define msh_main(argc,argv) main(argc,argv)
# define safe_read(fd,buf,count) read(fd,buf,count)
# define NOT_LONE_DASH(s) ((s)[0] != '-' || (s)[1])
# define LONE_CHAR(s,c) ((s)[0] == (c) && !(s)[1])
# define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
static char *find_applet_by_name(const char *applet)
{
	return NULL;
}
static char *utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
	unsigned i, out, res;
	assert(sizeof(unsigned) == 4);
	if (buflen) {
		out = 0;
		for (i = 1000000000; i; i /= 10) {
			res = n / i;
			if (res || out || i == 1) {
				if (!--buflen) break;
				out++;
				n -= res*i;
				*buf++ = '0' + res;
			}
		}
	}
	return buf;
}
static char *itoa_to_buf(int n, char *buf, unsigned buflen)
{
	if (buflen && n < 0) {
		n = -n;
		*buf++ = '-';
		buflen--;
	}
	return utoa_to_buf((unsigned)n, buf, buflen);
}
static char local_buf[12];
static char *itoa(int n)
{
	*(itoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';
	return local_buf;
}
#else
# include "busybox.h"
extern char **environ;
#endif

/*#define MSHDEBUG 1*/

#ifdef MSHDEBUG
int mshdbg = MSHDEBUG;

#define DBGPRINTF(x)	if (mshdbg>0) printf x
#define DBGPRINTF0(x)	if (mshdbg>0) printf x
#define DBGPRINTF1(x)	if (mshdbg>1) printf x
#define DBGPRINTF2(x)	if (mshdbg>2) printf x
#define DBGPRINTF3(x)	if (mshdbg>3) printf x
#define DBGPRINTF4(x)	if (mshdbg>4) printf x
#define DBGPRINTF5(x)	if (mshdbg>5) printf x
#define DBGPRINTF6(x)	if (mshdbg>6) printf x
#define DBGPRINTF7(x)	if (mshdbg>7) printf x
#define DBGPRINTF8(x)	if (mshdbg>8) printf x
#define DBGPRINTF9(x)	if (mshdbg>9) printf x

int mshdbg_rc = 0;

#define RCPRINTF(x)	if (mshdbg_rc) printf x

#else

#define DBGPRINTF(x)
#define DBGPRINTF0(x) ((void)0)
#define DBGPRINTF1(x) ((void)0)
#define DBGPRINTF2(x) ((void)0)
#define DBGPRINTF3(x) ((void)0)
#define DBGPRINTF4(x) ((void)0)
#define DBGPRINTF5(x) ((void)0)
#define DBGPRINTF6(x) ((void)0)
#define DBGPRINTF7(x) ((void)0)
#define DBGPRINTF8(x) ((void)0)
#define DBGPRINTF9(x) ((void)0)

#define RCPRINTF(x) ((void)0)

#endif							/* MSHDEBUG */


#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
# define DEFAULT_ROOT_PROMPT "\\u:\\w> "
# define DEFAULT_USER_PROMPT "\\u:\\w$ "
#else
# define DEFAULT_ROOT_PROMPT "# "
# define DEFAULT_USER_PROMPT "$ "
#endif


/* -------- sh.h -------- */
/*
 * shell
 */

#define	LINELIM	  2100
#define	NPUSH	  8				/* limit to input nesting */

#undef NOFILE
#define	NOFILE	  20			/* Number of open files */
#define	NUFILE	  10			/* Number of user-accessible files */
#define	FDBASE	  10			/* First file usable by Shell */

/*
 * values returned by wait
 */
#define	WAITSIG(s)  ((s) & 0177)
#define	WAITVAL(s)  (((s) >> 8) & 0377)
#define	WAITCORE(s) (((s) & 0200) != 0)

/*
 * library and system definitions
 */
typedef void xint;				/* base type of jmp_buf, for not broken compilers */

/*
 * shell components
 */
#define	NOBLOCK	((struct op *)NULL)
#define	NOWORD	((char *)NULL)
#define	NOWORDS	((char **)NULL)
#define	NOPIPE	((int *)NULL)

/*
 * redirection
 */
struct ioword {
	short io_unit;				/* unit affected */
	short io_flag;				/* action (below) */
	char *io_name;				/* file name */
};

#define	IOREAD	 1				/* < */
#define	IOHERE	 2				/* << (here file) */
#define	IOWRITE	 4				/* > */
#define	IOCAT	 8				/* >> */
#define	IOXHERE	 16				/* ${}, ` in << */
#define	IODUP	 32				/* >&digit */
#define	IOCLOSE	 64				/* >&- */

#define	IODEFAULT (-1)			/* token for default IO unit */


/*
 * Description of a command or an operation on commands.
 * Might eventually use a union.
 */
struct op {
	int type;					/* operation type, see below */
	char **words;				/* arguments to a command */
	struct ioword **ioact;		/* IO actions (eg, < > >>) */
	struct op *left;
	struct op *right;
	char *str;					/* identifier for case and for */
};

#define	TCOM	1				/* command */
#define	TPAREN	2				/* (c-list) */
#define	TPIPE	3				/* a | b */
#define	TLIST	4				/* a [&;] b */
#define	TOR		5				/* || */
#define	TAND	6				/* && */
#define	TFOR	7
#define	TDO		8
#define	TCASE	9
#define	TIF		10
#define	TWHILE	11
#define	TUNTIL	12
#define	TELIF	13
#define	TPAT	14				/* pattern in case */
#define	TBRACE	15				/* {c-list} */
#define	TASYNC	16				/* c & */
/* Added to support "." file expansion */
#define	TDOT	17

/* Strings for names to make debug easier */
#ifdef MSHDEBUG
static const char *const T_CMD_NAMES[] = {
	"PLACEHOLDER",
	"TCOM",
	"TPAREN",
	"TPIPE",
	"TLIST",
	"TOR",
	"TAND",
	"TFOR",
	"TDO",
	"TCASE",
	"TIF",
	"TWHILE",
	"TUNTIL",
	"TELIF",
	"TPAT",
	"TBRACE",
	"TASYNC",
	"TDOT",
};
#endif

/*
 * actions determining the environment of a process
 */
#define FEXEC    1      /* execute without forking */

#define AREASIZE (90000)

/*
 * flags to control evaluation of words
 */
#define DOSUB    1      /* interpret $, `, and quotes */
#define DOBLANK  2      /* perform blank interpretation */
#define DOGLOB   4      /* interpret [?* */
#define DOKEY    8      /* move words with `=' to 2nd arg. list */
#define DOTRIM   16     /* trim resulting string */

#define DOALL    (DOSUB|DOBLANK|DOGLOB|DOKEY|DOTRIM)


struct brkcon {
	jmp_buf brkpt;
	struct brkcon *nextlev;
};


/*
 * flags:
 * -e: quit on error
 * -k: look for name=value everywhere on command line
 * -n: no execution
 * -t: exit after reading and executing one command
 * -v: echo as read
 * -x: trace
 * -u: unset variables net diagnostic
 */
static char flags['z' - 'a' + 1] ALIGN1;
/* this looks weird, but is OK ... we index FLAG with 'a'...'z' */
#define FLAG (flags - 'a')

/* moved to G: static char *trap[_NSIG + 1]; */
/* moved to G: static char ourtrap[_NSIG + 1]; */
static int trapset;				/* trap pending */

static int yynerrs;				/* yacc */

/* moved to G: static char line[LINELIM]; */

#if ENABLE_FEATURE_EDITING
static char *current_prompt;
static line_input_t *line_input_state;
#endif


/*
 * other functions
 */
static const char *rexecve(char *c, char **v, char **envp);
static char *evalstr(char *cp, int f);
static char *putn(int n);
static char *unquote(char *as);
static int rlookup(char *n);
static struct wdblock *glob(char *cp, struct wdblock *wb);
static int my_getc(int ec);
static int subgetc(char ec, int quoted);
static char **makenv(int all, struct wdblock *wb);
static char **eval(char **ap, int f);
static int setstatus(int s);
static int waitfor(int lastpid, int canintr);

static void onintr(int s);		/* SIGINT handler */

static int newenv(int f);
static void quitenv(void);
static void next(int f);
static void setdash(void);
static void onecommand(void);
static void runtrap(int i);


/* -------- area stuff -------- */

#define REGSIZE   sizeof(struct region)
#define GROWBY    (256)
/* #define SHRINKBY (64) */
#undef  SHRINKBY
#define FREE      (32767)
#define BUSY      (0)
#define ALIGN     (sizeof(int)-1)


struct region {
	struct region *next;
	int area;
};


/* -------- grammar stuff -------- */
typedef union {
	char *cp;
	char **wp;
	int i;
	struct op *o;
} YYSTYPE;

#define WORD    256
#define LOGAND  257
#define LOGOR   258
#define BREAK   259
#define IF      260
#define THEN    261
#define ELSE    262
#define ELIF    263
#define FI      264
#define CASE    265
#define ESAC    266
#define FOR     267
#define WHILE   268
#define UNTIL   269
#define DO      270
#define DONE    271
#define IN      272
/* Added for "." file expansion */
#define DOT     273

#define	YYERRCODE 300

/* flags to yylex */
#define	CONTIN 01     /* skip new lines to complete command */

static struct op *pipeline(int cf);
static struct op *andor(void);
static struct op *c_list(void);
static int synio(int cf);
static void musthave(int c, int cf);
static struct op *simple(void);
static struct op *nested(int type, int mark);
static struct op *command(int cf);
static struct op *dogroup(int onlydone);
static struct op *thenpart(void);
static struct op *elsepart(void);
static struct op *caselist(void);
static struct op *casepart(void);
static char **pattern(void);
static char **wordlist(void);
static struct op *list(struct op *t1, struct op *t2);
static struct op *block(int type, struct op *t1, struct op *t2, char **wp);
static struct op *newtp(void);
static struct op *namelist(struct op *t);
static char **copyw(void);
static void word(char *cp);
static struct ioword **copyio(void);
static struct ioword *io(int u, int f, char *cp);
static int yylex(int cf);
static int collect(int c, int c1);
static int dual(int c);
static void diag(int ec);
static char *tree(unsigned size);

/* -------- var.h -------- */

struct var {
	char *value;
	char *name;
	struct var *next;
	char status;
};

#define	COPYV	1				/* flag to setval, suggesting copy */
#define	RONLY	01				/* variable is read-only */
#define	EXPORT	02				/* variable is to be exported */
#define	GETCELL	04				/* name & value space was got with getcell */

static int yyparse(void);

static int execute(struct op *t, int *pin, int *pout, int act);


#define AFID_NOBUF	(~0)
#define AFID_ID		0


/* -------- io.h -------- */
/* io buffer */
struct iobuf {
	unsigned id;            /* buffer id */
	char buf[512];          /* buffer */
	char *bufp;             /* pointer into buffer */
	char *ebufp;            /* pointer to end of buffer */
};

/* possible arguments to an IO function */
struct ioarg {
	const char *aword;
	char **awordlist;
	int afile;              /* file descriptor */
	unsigned afid;          /* buffer id */
	long afpos;             /* file position */
	struct iobuf *afbuf;    /* buffer for this file */
};

/* an input generator's state */
struct io {
	int (*iofn) (struct ioarg *, struct io *);
	struct ioarg *argp;
	int peekc;
	char prev;              /* previous character read by readc() */
	char nlcount;           /* for `'s */
	char xchar;             /* for `'s */
	char task;              /* reason for pushed IO */
};

#define	XOTHER	0				/* none of the below */
#define	XDOLL	1				/* expanding ${} */
#define	XGRAVE	2				/* expanding `'s */
#define	XIO	3				/* file IO */

/* in substitution */
#define	INSUB()	(e.iop->task == XGRAVE || e.iop->task == XDOLL)

static struct ioarg temparg = { 0, 0, 0, AFID_NOBUF, 0 };	/* temporary for PUSHIO */
/* moved to G: static struct ioarg ioargstack[NPUSH]; */
static struct io iostack[NPUSH];
/* moved to G: static struct iobuf sharedbuf = { AFID_NOBUF }; */
/* moved to G: static struct iobuf mainbuf = { AFID_NOBUF }; */
static unsigned bufid = AFID_ID;	/* buffer id counter */

#define	RUN(what,arg,gen) ((temparg.what = (arg)), run(&temparg,(gen)))


/*
 * input generators for IO structure
 */
static int nlchar(struct ioarg *ap);
static int strchar(struct ioarg *ap);
static int qstrchar(struct ioarg *ap);
static int filechar(struct ioarg *ap);
static int herechar(struct ioarg *ap);
static int linechar(struct ioarg *ap);
static int gravechar(struct ioarg *ap, struct io *iop);
static int qgravechar(struct ioarg *ap, struct io *iop);
static int dolchar(struct ioarg *ap);
static int wdchar(struct ioarg *ap);
static void scraphere(void);
static void freehere(int area);
static void gethere(void);
static void markhere(char *s, struct ioword *iop);
static int herein(char *hname, int xdoll);
static int run(struct ioarg *argp, int (*f) (struct ioarg *));


static int eofc(void);
static int readc(void);
static void unget(int c);
static void ioecho(char c);


/*
 * IO control
 */
static void pushio(struct ioarg *argp, int (*f) (struct ioarg *));
#define PUSHIO(what,arg,gen) ((temparg.what = (arg)), pushio(&temparg,(gen)))
static int remap(int fd);
static int openpipe(int *pv);
static void closepipe(int *pv);
static struct io *setbase(struct io *ip);

/* -------- word.h -------- */

#define	NSTART	16				/* default number of words to allow for initially */

struct wdblock {
	short w_bsize;
	short w_nword;
	/* bounds are arbitrary */
	char *w_words[1];
};

static struct wdblock *addword(char *wd, struct wdblock *wb);
static struct wdblock *newword(int nw);
static char **getwords(struct wdblock *wb);

/* -------- misc stuff -------- */

static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp);
static int iosetup(struct ioword *iop, int pipein, int pipeout);
static void brkset(struct brkcon *bc);
static int dolabel(struct op *t);
static int dohelp(struct op *t);
static int dochdir(struct op *t);
static int doshift(struct op *t);
static int dologin(struct op *t);
static int doumask(struct op *t);
static int doexec(struct op *t);
static int dodot(struct op *t);
static int dowait(struct op *t);
static int doread(struct op *t);
static int doeval(struct op *t);
static int dotrap(struct op *t);
static int getsig(char *s);
static void setsig(int n, sighandler_t f);
static int getn(char *as);
static int dobreak(struct op *t);
static int docontinue(struct op *t);
static int brkcontin(char *cp, int val);
static int doexit(struct op *t);
static int doexport(struct op *t);
static int doreadonly(struct op *t);
static void rdexp(char **wp, void (*f) (struct var *), int key);
static void badid(char *s);
static int doset(struct op *t);
static void varput(char *s, int out);
static int dotimes(struct op *t);
static int expand(const char *cp, struct wdblock **wbp, int f);
static char *blank(int f);
static int dollar(int quoted);
static int grave(int quoted);
static void globname(char *we, char *pp);
static char *generate(char *start1, char *end1, char *middle, char *end);
static int anyspcl(struct wdblock *wb);
static int xstrcmp(char *p1, char *p2);
static void glob0(char *a0, unsigned a1, int a2,
				  int (*a3) (char *, char *));
static void readhere(char **name, char *s, int ec);
static int xxchar(struct ioarg *ap);

struct here {
	char *h_tag;
	int h_dosub;
	struct ioword *h_iop;
	struct here *h_next;
};

static const char *const signame[] = {
	"Signal 0",
	"Hangup",
	NULL,  /* interrupt */
	"Quit",
	"Illegal instruction",
	"Trace/BPT trap",
	"Abort",
	"Bus error",
	"Floating Point Exception",
	"Killed",
	"SIGUSR1",
	"SIGSEGV",
	"SIGUSR2",
	NULL,  /* broken pipe */
	"Alarm clock",
	"Terminated"
};


struct res {
	const char *r_name;
	int r_val;
};
static const struct res restab[] = {
	{ "for"  , FOR    },
	{ "case" , CASE   },
	{ "esac" , ESAC   },
	{ "while", WHILE  },
	{ "do"   , DO     },
	{ "done" , DONE   },
	{ "if"   , IF     },
	{ "in"   , IN     },
	{ "then" , THEN   },
	{ "else" , ELSE   },
	{ "elif" , ELIF   },
	{ "until", UNTIL  },
	{ "fi"   , FI     },
	{ ";;"   , BREAK  },
	{ "||"   , LOGOR  },
	{ "&&"   , LOGAND },
	{ "{"    , '{'    },
	{ "}"    , '}'    },
	{ "."    , DOT    },
	{ NULL   , 0      },
};

struct builtincmd {
	const char *name;
	int (*builtinfunc)(struct op *t);
};
static const struct builtincmd builtincmds[] = {
	{ "."       , dodot      },
	{ ":"       , dolabel    },
	{ "break"   , dobreak    },
	{ "cd"      , dochdir    },
	{ "continue", docontinue },
	{ "eval"    , doeval     },
	{ "exec"    , doexec     },
	{ "exit"    , doexit     },
	{ "export"  , doexport   },
	{ "help"    , dohelp     },
	{ "login"   , dologin    },
	{ "newgrp"  , dologin    },
	{ "read"    , doread     },
	{ "readonly", doreadonly },
	{ "set"     , doset      },
	{ "shift"   , doshift    },
	{ "times"   , dotimes    },
	{ "trap"    , dotrap     },
	{ "umask"   , doumask    },
	{ "wait"    , dowait     },
	{ NULL      , NULL       },
};

static struct op *scantree(struct op *);
static struct op *dowholefile(int, int);


/* Globals */
static char **dolv;
static int dolc;
static int exstat;
static char gflg;
static int interactive;			/* Is this an interactive shell */
static int execflg;
static int multiline;			/* \n changed to ; */
static struct op *outtree;		/* result from parser */
static xint *failpt;
static xint *errpt;
static struct brkcon *brklist;
static int isbreak;
static struct wdblock *wdlist;
static struct wdblock *iolist;

#ifdef MSHDEBUG
static struct var *mshdbg_var;
#endif
static struct var *vlist;		/* dictionary */
static struct var *homedir;		/* home directory */
static struct var *prompt;		/* main prompt */
static struct var *cprompt;		/* continuation prompt */
static struct var *path;		/* search path for commands */
static struct var *shell;		/* shell to interpret command files */
static struct var *ifs;			/* field separators */

static int areanum;                     /* current allocation area */
static int intr;                        /* interrupt pending */
static int inparse;
static char *null = (char*)"";          /* null value for variable */
static int heedint = 1;                 /* heed interrupt signals */
static void (*qflag)(int) = SIG_IGN;
static int startl;
static int peeksym;
static int nlseen;
static int iounit = IODEFAULT;
static YYSTYPE yylval;
static char *elinep; /* done in main(): = line + sizeof(line) - 5 */

static struct here *inhere;     /* list of hear docs while parsing */
static struct here *acthere;    /* list of active here documents */
static struct region *areabot;  /* bottom of area */
static struct region *areatop;  /* top of area */
static struct region *areanxt;  /* starting point of scan */
static void *brktop;
static void *brkaddr;

/*
 * parsing & execution environment
 */
struct env {
	char *linep;
	struct io *iobase;
	struct io *iop;
	xint *errpt;		/* void * */
	int iofd;
	struct env *oenv;
};

static struct env e = {
	NULL /* set to line in main() */, /* linep:  char ptr */
	iostack,                /* iobase:  struct io ptr */
	iostack - 1,            /* iop:  struct io ptr */
	(xint *) NULL,          /* errpt:  void ptr for errors? */
	FDBASE,                 /* iofd:  file desc  */
	(struct env *) NULL     /* oenv:  struct env ptr */
};


struct globals {
	char ourtrap[_NSIG + 1];
	char *trap[_NSIG + 1];
	struct iobuf sharedbuf; /* in main(): set to { AFID_NOBUF } */
	struct iobuf mainbuf; /* in main(): set to { AFID_NOBUF } */
	struct ioarg ioargstack[NPUSH];
	char filechar_cmdbuf[BUFSIZ];
	char line[LINELIM];
	char child_cmd[LINELIM];
};

#define G (*ptr_to_globals)
#define ourtrap         (G.ourtrap        )
#define trap            (G.trap           )
#define sharedbuf       (G.sharedbuf      )
#define mainbuf         (G.mainbuf        )
#define ioargstack      (G.ioargstack     )
#define filechar_cmdbuf (G.filechar_cmdbuf)
#define line            (G.line           )
#define child_cmd       (G.child_cmd      )


#ifdef MSHDEBUG
void print_t(struct op *t)
{
	DBGPRINTF(("T: t=%p, type %s, words=%p, IOword=%p\n", t,
	          T_CMD_NAMES[t->type], t->words, t->ioact));

	if (t->words) {
		DBGPRINTF(("T: W1: %s", t->words[0]));
	}
}

void print_tree(struct op *head)
{
	if (head == NULL) {
		DBGPRINTF(("PRINT_TREE: no tree\n"));
		return;
	}

	DBGPRINTF(("NODE: %p,  left %p, right %p\n", head, head->left,
			   head->right));

	if (head->left)
		print_tree(head->left);

	if (head->right)
		print_tree(head->right);
}
#endif /* MSHDEBUG */


/*
 * IO functions
 */
static void prs(const char *s)
{
	if (*s)
		write(2, s, strlen(s));
}

static void prn(unsigned u)
{
	prs(itoa(u));
}

static void echo(char **wp)
{
	int i;

	prs("+");
	for (i = 0; wp[i]; i++) {
		if (i)
			prs(" ");
		prs(wp[i]);
	}
	prs("\n");
}

static void closef(int i)
{
	if (i > 2)
		close(i);
}

static void closeall(void)
{
	int u;

	for (u = NUFILE; u < NOFILE;)
		close(u++);
}


/* fail but return to process next command */
static void fail(void) ATTRIBUTE_NORETURN;
static void fail(void)
{
	longjmp(failpt, 1);
	/* NOTREACHED */
}

/* abort shell (or fail in subshell) */
static void leave(void) ATTRIBUTE_NORETURN;
static void leave(void)
{
	DBGPRINTF(("LEAVE: leave called!\n"));

	if (execflg)
		fail();
	scraphere();
	freehere(1);
	runtrap(0);
	_exit(exstat);
	/* NOTREACHED */
}

static void warn(const char *s)
{
	if (*s) {
		prs(s);
		exstat = -1;
	}
	prs("\n");
	if (FLAG['e'])
		leave();
}

static void err(const char *s)
{
	warn(s);
	if (FLAG['n'])
		return;
	if (!interactive)
		leave();
	if (e.errpt)
		longjmp(e.errpt, 1);
	closeall();
	e.iop = e.iobase = iostack;
}


/* -------- area.c -------- */

/*
 * All memory between (char *)areabot and (char *)(areatop+1) is
 * exclusively administered by the area management routines.
 * It is assumed that sbrk() and brk() manipulate the high end.
 */

#define sbrk(X) ({ \
	void * __q = (void *)-1; \
	if (brkaddr + (int)(X) < brktop) { \
		__q = brkaddr; \
		brkaddr += (int)(X); \
	} \
	__q; \
})

static void initarea(void)
{
	brkaddr = xmalloc(AREASIZE);
	brktop = brkaddr + AREASIZE;

	while ((long) sbrk(0) & ALIGN)
		sbrk(1);
	areabot = (struct region *) sbrk(REGSIZE);

	areabot->next = areabot;
	areabot->area = BUSY;
	areatop = areabot;
	areanxt = areabot;
}

static char *getcell(unsigned nbytes)
{
	int nregio;
	struct region *p, *q;
	int i;

	if (nbytes == 0) {
		puts("getcell(0)");
		abort();
	}
	/* silly and defeats the algorithm */
	/*
	 * round upwards and add administration area
	 */
	nregio = (nbytes + (REGSIZE - 1)) / REGSIZE + 1;
	p = areanxt;
	for (;;) {
		if (p->area > areanum) {
			/*
			 * merge free cells
			 */
			while ((q = p->next)->area > areanum && q != areanxt)
				p->next = q->next;
			/*
			 * exit loop if cell big enough
			 */
			if (q >= p + nregio)
				goto found;
		}
		p = p->next;
		if (p == areanxt)
			break;
	}
	i = nregio >= GROWBY ? nregio : GROWBY;
	p = (struct region *) sbrk(i * REGSIZE);
	if (p == (struct region *) -1)
		return NULL;
	p--;
	if (p != areatop) {
		puts("not contig");
		abort();				/* allocated areas are contiguous */
	}
	q = p + i;
	p->next = q;
	p->area = FREE;
	q->next = areabot;
	q->area = BUSY;
	areatop = q;
 found:
	/*
	 * we found a FREE area big enough, pointed to by 'p', and up to 'q'
	 */
	areanxt = p + nregio;
	if (areanxt < q) {
		/*
		 * split into requested area and rest
		 */
		if (areanxt + 1 > q) {
			puts("OOM");
			abort();			/* insufficient space left for admin */
		}
		areanxt->next = q;
		areanxt->area = FREE;
		p->next = areanxt;
	}
	p->area = areanum;
	return (char *) (p + 1);
}

static void freecell(char *cp)
{
	struct region *p;

	p = (struct region *) cp;
	if (p != NULL) {
		p--;
		if (p < areanxt)
			areanxt = p;
		p->area = FREE;
	}
}
#define	DELETE(obj) freecell((char *)obj)

static void freearea(int a)
{
	struct region *p, *top;

	top = areatop;
	for (p = areabot; p != top; p = p->next)
		if (p->area >= a)
			p->area = FREE;
}

static void setarea(char *cp, int a)
{
	struct region *p;

	p = (struct region *) cp;
	if (p != NULL)
		(p - 1)->area = a;
}

static int getarea(char *cp)
{
	return ((struct region *) cp - 1)->area;
}

static void garbage(void)
{
	struct region *p, *q, *top;

	top = areatop;
	for (p = areabot; p != top; p = p->next) {
		if (p->area > areanum) {
			while ((q = p->next)->area > areanum)
				p->next = q->next;
			areanxt = p;
		}
	}
#ifdef SHRINKBY
	if (areatop >= q + SHRINKBY && q->area > areanum) {
		brk((char *) (q + 1));
		q->next = areabot;
		q->area = BUSY;
		areatop = q;
	}
#endif
}

static char *space(int n)
{
	char *cp;

	cp = getcell(n);
	if (cp == NULL)
		err("out of string space");
	return cp;
}

static char *strsave(const char *s, int a)
{
	char *cp;

	cp = space(strlen(s) + 1);
	if (cp == NULL) {
// FIXME: I highly doubt this is good.
		return (char*)"";
	}
	setarea(cp, a);
	strcpy(cp, s);
	return cp;
}


/* -------- var.c -------- */

static int eqname(const char *n1, const char *n2)
{
	for (; *n1 != '=' && *n1 != '\0'; n1++)
		if (*n2++ != *n1)
			return 0;
	return *n2 == '\0' || *n2 == '=';
}

static const char *findeq(const char *cp)
{
	while (*cp != '\0' && *cp != '=')
		cp++;
	return cp;
}

/*
 * Find the given name in the dictionary
 * and return its value.  If the name was
 * not previously there, enter it now and
 * return a null value.
 */
static struct var *lookup(const char *n)
{
// FIXME: dirty hack
	static struct var dummy;

	struct var *vp;
	const char *cp;
	char *xp;
	int c;

	if (isdigit(*n)) {
		dummy.name = (char*)n;
		for (c = 0; isdigit(*n) && c < 1000; n++)
			c = c * 10 + *n - '0';
		dummy.status = RONLY;
		dummy.value = (c <= dolc ? dolv[c] : null);
		return &dummy;
	}

	for (vp = vlist; vp; vp = vp->next)
		if (eqname(vp->name, n))
			return vp;

	cp = findeq(n);
	vp = (struct var *) space(sizeof(*vp));
	if (vp == 0 || (vp->name = space((int) (cp - n) + 2)) == 0) {
		dummy.name = dummy.value = (char*)"";
		return &dummy;
	}

	xp = vp->name;
	while ((*xp = *n++) != '\0' && *xp != '=')
		xp++;
	*xp++ = '=';
	*xp = '\0';
	setarea((char *) vp, 0);
	setarea((char *) vp->name, 0);
	vp->value = null;
	vp->next = vlist;
	vp->status = GETCELL;
	vlist = vp;
	return vp;
}

/*
 * if name is not NULL, it must be
 * a prefix of the space `val',
 * and end with `='.
 * this is all so that exporting
 * values is reasonably painless.
 */
static void nameval(struct var *vp, const char *val, const char *name)
{
	const char *cp;
	char *xp;
	int fl;

	if (vp->status & RONLY) {
		xp = vp->name;
		while (*xp && *xp != '=')
			fputc(*xp++, stderr);
		err(" is read-only");
		return;
	}
	fl = 0;
	if (name == NULL) {
		xp = space(strlen(vp->name) + strlen(val) + 2);
		if (xp == NULL)
			return;
		/* make string: name=value */
		setarea(xp, 0);
		name = xp;
		cp = vp->name;
		while ((*xp = *cp++) != '\0' && *xp != '=')
			xp++;
		*xp++ = '=';
		strcpy(xp, val);
		val = xp;
		fl = GETCELL;
	}
	if (vp->status & GETCELL)
		freecell(vp->name);		/* form new string `name=value' */
	vp->name = (char*)name;
	vp->value = (char*)val;
	vp->status |= fl;
}

/*
 * give variable at `vp' the value `val'.
 */
static void setval(struct var *vp, const char *val)
{
	nameval(vp, val, NULL);
}

static void export(struct var *vp)
{
	vp->status |= EXPORT;
}

static void ronly(struct var *vp)
{
	if (isalpha(vp->name[0]) || vp->name[0] == '_')	/* not an internal symbol */
		vp->status |= RONLY;
}

static int isassign(const char *s)
{
	unsigned char c;
	DBGPRINTF7(("ISASSIGN: enter, s=%s\n", s));

	c = *s;
	/* no isalpha() - we shouldn't use locale */
	/* c | 0x20 - lowercase (Latin) letters */
	if (c != '_' && (unsigned)((c|0x20) - 'a') > 25)
		/* not letter */
		return 0;

	while (1) {
		c = *++s;
		if (c == '=')
			return 1;
		if (c == '\0')
			return 0;
		if (c != '_'
		 && (unsigned)(c - '0') > 9  /* not number */
		 && (unsigned)((c|0x20) - 'a') > 25 /* not letter */
		) {
			return 0;
		}
	}
}

static int assign(const char *s, int cf)
{
	const char *cp;
	struct var *vp;

	DBGPRINTF7(("ASSIGN: enter, s=%s, cf=%d\n", s, cf));

	if (!isalpha(*s) && *s != '_')
		return 0;
	for (cp = s; *cp != '='; cp++)
		if (*cp == '\0' || (!isalnum(*cp) && *cp != '_'))
			return 0;
	vp = lookup(s);
	nameval(vp, ++cp, cf == COPYV ? NULL : s);
	if (cf != COPYV)
		vp->status &= ~GETCELL;
	return 1;
}

static int checkname(char *cp)
{
	DBGPRINTF7(("CHECKNAME: enter, cp=%s\n", cp));

	if (!isalpha(*cp++) && *(cp - 1) != '_')
		return 0;
	while (*cp)
		if (!isalnum(*cp++) && *(cp - 1) != '_')
			return 0;
	return 1;
}

static void putvlist(int f, int out)
{
	struct var *vp;

	for (vp = vlist; vp; vp = vp->next) {
		if (vp->status & f && (isalpha(*vp->name) || *vp->name == '_')) {
			if (vp->status & EXPORT)
				write(out, "export ", 7);
			if (vp->status & RONLY)
				write(out, "readonly ", 9);
			write(out, vp->name, (int) (findeq(vp->name) - vp->name));
			write(out, "\n", 1);
		}
	}
}


/*
 * trap handling
 */
static void sig(int i)
{
	trapset = i;
	signal(i, sig);
}

static void runtrap(int i)
{
	char *trapstr;

	trapstr = trap[i];
	if (trapstr == NULL)
		return;

	if (i == 0)
		trap[i] = NULL;

	RUN(aword, trapstr, nlchar);
}


static void setdash(void)
{
	char *cp;
	int c;
	char m['z' - 'a' + 1];

	cp = m;
	for (c = 'a'; c <= 'z'; c++)
		if (FLAG[c])
			*cp++ = c;
	*cp = '\0';
	setval(lookup("-"), m);
}

static int newfile(char *s)
{
	int f;

	DBGPRINTF7(("NEWFILE: opening %s\n", s));

	f = 0;
	if (NOT_LONE_DASH(s)) {
		DBGPRINTF(("NEWFILE: s is %s\n", s));
		f = open(s, O_RDONLY);
		if (f < 0) {
			prs(s);
			err(": cannot open");
			return 1;
		}
	}

	next(remap(f));
	return 0;
}


struct op *scantree(struct op *head)
{
	struct op *dotnode;

	if (head == NULL)
		return NULL;

	if (head->left != NULL) {
		dotnode = scantree(head->left);
		if (dotnode)
			return dotnode;
	}

	if (head->right != NULL) {
		dotnode = scantree(head->right);
		if (dotnode)
			return dotnode;
	}

	if (head->words == NULL)
		return NULL;

	DBGPRINTF5(("SCANTREE: checking node %p\n", head));

	if ((head->type != TDOT) && LONE_CHAR(head->words[0], '.')) {
		DBGPRINTF5(("SCANTREE: dot found in node %p\n", head));
		return head;
	}

	return NULL;
}


static void onecommand(void)
{
	int i;
	jmp_buf m1;

	DBGPRINTF(("ONECOMMAND: enter, outtree=%p\n", outtree));

	while (e.oenv)
		quitenv();

	areanum = 1;
	freehere(areanum);
	freearea(areanum);
	garbage();
	wdlist = 0;
	iolist = 0;
	e.errpt = 0;
	e.linep = line;
	yynerrs = 0;
	multiline = 0;
	inparse = 1;
	intr = 0;
	execflg = 0;

	failpt = m1;
	setjmp(failpt);		/* Bruce Evans' fix */
	failpt = m1;
	if (setjmp(failpt) || yyparse() || intr) {
		DBGPRINTF(("ONECOMMAND: this is not good.\n"));

		while (e.oenv)
			quitenv();
		scraphere();
		if (!interactive && intr)
			leave();
		inparse = 0;
		intr = 0;
		return;
	}

	inparse = 0;
	brklist = 0;
	intr = 0;
	execflg = 0;

	if (!FLAG['n']) {
		DBGPRINTF(("ONECOMMAND: calling execute, t=outtree=%p\n",
				   outtree));
		execute(outtree, NOPIPE, NOPIPE, 0);
	}

	if (!interactive && intr) {
		execflg = 0;
		leave();
	}

	i = trapset;
	if (i != 0) {
		trapset = 0;
		runtrap(i);
	}
}

static int newenv(int f)
{
	struct env *ep;

	DBGPRINTF(("NEWENV: f=%d (indicates quitenv and return)\n", f));

	if (f) {
		quitenv();
		return 1;
	}

	ep = (struct env *) space(sizeof(*ep));
	if (ep == NULL) {
		while (e.oenv)
			quitenv();
		fail();
	}
	*ep = e;
	e.oenv = ep;
	e.errpt = errpt;

	return 0;
}

static void quitenv(void)
{
	struct env *ep;
	int fd;

	DBGPRINTF(("QUITENV: e.oenv=%p\n", e.oenv));

	ep = e.oenv;
	if (ep != NULL) {
		fd = e.iofd;
		e = *ep;
		/* should close `'d files */
		DELETE(ep);
		while (--fd >= e.iofd)
			close(fd);
	}
}

/*
 * Is character c in s?
 */
static int any(int c, const char *s)
{
	while (*s)
		if (*s++ == c)
			return 1;
	return 0;
}

/*
 * Is any character from s1 in s2?
 */
static int anys(const char *s1, const char *s2)
{
	while (*s1)
		if (any(*s1++, s2))
			return 1;
	return 0;
}

static char *putn(int n)
{
	return itoa(n);
}

static void next(int f)
{
	PUSHIO(afile, f, filechar);
}

static void onintr(int s)					/* ANSI C requires a parameter */
{
	signal(SIGINT, onintr);
	intr = 1;
	if (interactive) {
		if (inparse) {
			prs("\n");
			fail();
		}
	} else if (heedint) {
		execflg = 0;
		leave();
	}
}


/* -------- gmatch.c -------- */
/*
 * int gmatch(string, pattern)
 * char *string, *pattern;
 *
 * Match a pattern as in sh(1).
 */

#define	CMASK	0377
#define	QUOTE	0200
#define	QMASK	(CMASK & ~QUOTE)
#define	NOT	'!'					/* might use ^ */

static const char *cclass(const char *p, int sub)
{
	int c, d, not, found;

	not = (*p == NOT);
	if (not != 0)
		p++;
	found = not;
	do {
		if (*p == '\0')
			return NULL;
		c = *p & CMASK;
		if (p[1] == '-' && p[2] != ']') {
			d = p[2] & CMASK;
			p++;
		} else
			d = c;
		if (c == sub || (c <= sub && sub <= d))
			found = !not;
	} while (*++p != ']');
	return found ? p + 1 : NULL;
}

static int gmatch(const char *s, const char *p)
{
	int sc, pc;

	if (s == NULL || p == NULL)
		return 0;

	while ((pc = *p++ & CMASK) != '\0') {
		sc = *s++ & QMASK;
		switch (pc) {
		case '[':
			p = cclass(p, sc);
			if (p == NULL)
				return 0;
			break;

		case '?':
			if (sc == 0)
				return 0;
			break;

		case '*':
			s--;
			do {
				if (*p == '\0' || gmatch(s, p))
					return 1;
			} while (*s++ != '\0');
			return 0;

		default:
			if (sc != (pc & ~QUOTE))
				return 0;
		}
	}
	return *s == '\0';
}


/* -------- csyn.c -------- */
/*
 * shell: syntax (C version)
 */

static void yyerror(const char *s) ATTRIBUTE_NORETURN;
static void yyerror(const char *s)
{
	yynerrs++;
	if (interactive && e.iop <= iostack) {
		multiline = 0;
		while (eofc() == 0 && yylex(0) != '\n');
	}
	err(s);
	fail();
}

static void zzerr(void) ATTRIBUTE_NORETURN;
static void zzerr(void)
{
	yyerror("syntax error");
}

int yyparse(void)
{
	DBGPRINTF7(("YYPARSE: enter...\n"));

	startl = 1;
	peeksym = 0;
	yynerrs = 0;
	outtree = c_list();
	musthave('\n', 0);
	return (yynerrs != 0);
}

static struct op *pipeline(int cf)
{
	struct op *t, *p;
	int c;

	DBGPRINTF7(("PIPELINE: enter, cf=%d\n", cf));

	t = command(cf);

	DBGPRINTF9(("PIPELINE: t=%p\n", t));

	if (t != NULL) {
		while ((c = yylex(0)) == '|') {
			p = command(CONTIN);
			if (p == NULL) {
				DBGPRINTF8(("PIPELINE: error!\n"));
				zzerr();
			}

			if (t->type != TPAREN && t->type != TCOM) {
				/* shell statement */
				t = block(TPAREN, t, NOBLOCK, NOWORDS);
			}

			t = block(TPIPE, t, p, NOWORDS);
		}
		peeksym = c;
	}

	DBGPRINTF7(("PIPELINE: returning t=%p\n", t));
	return t;
}

static struct op *andor(void)
{
	struct op *t, *p;
	int c;

	DBGPRINTF7(("ANDOR: enter...\n"));

	t = pipeline(0);

	DBGPRINTF9(("ANDOR: t=%p\n", t));

	if (t != NULL) {
		while ((c = yylex(0)) == LOGAND || c == LOGOR) {
			p = pipeline(CONTIN);
			if (p == NULL) {
				DBGPRINTF8(("ANDOR: error!\n"));
				zzerr();
			}

			t = block(c == LOGAND ? TAND : TOR, t, p, NOWORDS);
		}						/* WHILE */

		peeksym = c;
	}

	DBGPRINTF7(("ANDOR: returning t=%p\n", t));
	return t;
}

static struct op *c_list(void)
{
	struct op *t, *p;
	int c;

	DBGPRINTF7(("C_LIST: enter...\n"));

	t = andor();

	if (t != NULL) {
		peeksym = yylex(0);
		if (peeksym == '&')
			t = block(TASYNC, t, NOBLOCK, NOWORDS);

		while ((c = yylex(0)) == ';' || c == '&'
			   || (multiline && c == '\n')) {

			p = andor();
			if (p== NULL)
				return t;

			peeksym = yylex(0);
			if (peeksym == '&')
				p = block(TASYNC, p, NOBLOCK, NOWORDS);

			t = list(t, p);
		}						/* WHILE */

		peeksym = c;
	}
	/* IF */
	DBGPRINTF7(("C_LIST: returning t=%p\n", t));
	return t;
}

static int synio(int cf)
{
	struct ioword *iop;
	int i;
	int c;

	DBGPRINTF7(("SYNIO: enter, cf=%d\n", cf));

	c = yylex(cf);
	if (c != '<' && c != '>') {
		peeksym = c;
		return 0;
	}

	i = yylval.i;
	musthave(WORD, 0);
	iop = io(iounit, i, yylval.cp);
	iounit = IODEFAULT;

	if (i & IOHERE)
		markhere(yylval.cp, iop);

	DBGPRINTF7(("SYNIO: returning 1\n"));
	return 1;
}

static void musthave(int c, int cf)
{
	peeksym = yylex(cf);
	if (peeksym != c) {
		DBGPRINTF7(("MUSTHAVE: error!\n"));
		zzerr();
	}

	peeksym = 0;
}

static struct op *simple(void)
{
	struct op *t;

	t = NULL;
	for (;;) {
		switch (peeksym = yylex(0)) {
		case '<':
		case '>':
			(void) synio(0);
			break;

		case WORD:
			if (t == NULL) {
				t = newtp();
				t->type = TCOM;
			}
			peeksym = 0;
			word(yylval.cp);
			break;

		default:
			return t;
		}
	}
}

static struct op *nested(int type, int mark)
{
	struct op *t;

	DBGPRINTF3(("NESTED: enter, type=%d, mark=%d\n", type, mark));

	multiline++;
	t = c_list();
	musthave(mark, 0);
	multiline--;
	return block(type, t, NOBLOCK, NOWORDS);
}

static struct op *command(int cf)
{
	struct op *t;
	struct wdblock *iosave;
	int c;

	DBGPRINTF(("COMMAND: enter, cf=%d\n", cf));

	iosave = iolist;
	iolist = NULL;

	if (multiline)
		cf |= CONTIN;

	while (synio(cf))
		cf = 0;

	c = yylex(cf);

	switch (c) {
	default:
		peeksym = c;
		t = simple();
		if (t == NULL) {
			if (iolist == NULL)
				return NULL;
			t = newtp();
			t->type = TCOM;
		}
		break;

	case '(':
		t = nested(TPAREN, ')');
		break;

	case '{':
		t = nested(TBRACE, '}');
		break;

	case FOR:
		t = newtp();
		t->type = TFOR;
		musthave(WORD, 0);
		startl = 1;
		t->str = yylval.cp;
		multiline++;
		t->words = wordlist();
		c = yylex(0);
		if (c != '\n' && c != ';')
			peeksym = c;
		t->left = dogroup(0);
		multiline--;
		break;

	case WHILE:
	case UNTIL:
		multiline++;
		t = newtp();
		t->type = c == WHILE ? TWHILE : TUNTIL;
		t->left = c_list();
		t->right = dogroup(1);
		t->words = NULL;
		multiline--;
		break;

	case CASE:
		t = newtp();
		t->type = TCASE;
		musthave(WORD, 0);
		t->str = yylval.cp;
		startl++;
		multiline++;
		musthave(IN, CONTIN);
		startl++;

		t->left = caselist();

		musthave(ESAC, 0);
		multiline--;
		break;

	case IF:
		multiline++;
		t = newtp();
		t->type = TIF;
		t->left = c_list();
		t->right = thenpart();
		musthave(FI, 0);
		multiline--;
		break;

	case DOT:
		t = newtp();
		t->type = TDOT;

		musthave(WORD, 0);		/* gets name of file */
		DBGPRINTF7(("COMMAND: DOT clause, yylval.cp is %s\n", yylval.cp));

		word(yylval.cp);		/* add word to wdlist */
		word(NOWORD);			/* terminate  wdlist */
		t->words = copyw();		/* dup wdlist */
		break;

	}

	while (synio(0));

	t = namelist(t);
	iolist = iosave;

	DBGPRINTF(("COMMAND: returning %p\n", t));

	return t;
}

static struct op *dowholefile(int type, int mark)
{
	struct op *t;

	DBGPRINTF(("DOWHOLEFILE: enter, type=%d, mark=%d\n", type, mark));

	multiline++;
	t = c_list();
	multiline--;
	t = block(type, t, NOBLOCK, NOWORDS);
	DBGPRINTF(("DOWHOLEFILE: return t=%p\n", t));
	return t;
}

static struct op *dogroup(int onlydone)
{
	int c;
	struct op *mylist;

	c = yylex(CONTIN);
	if (c == DONE && onlydone)
		return NULL;
	if (c != DO)
		zzerr();
	mylist = c_list();
	musthave(DONE, 0);
	return mylist;
}

static struct op *thenpart(void)
{
	int c;
	struct op *t;

	c = yylex(0);
	if (c != THEN) {
		peeksym = c;
		return NULL;
	}
	t = newtp();
	t->type = 0;
	t->left = c_list();
	if (t->left == NULL)
		zzerr();
	t->right = elsepart();
	return t;
}

static struct op *elsepart(void)
{
	int c;
	struct op *t;

	switch (c = yylex(0)) {
	case ELSE:
		t = c_list();
		if (t == NULL)
			zzerr();
		return t;

	case ELIF:
		t = newtp();
		t->type = TELIF;
		t->left = c_list();
		t->right = thenpart();
		return t;

	default:
		peeksym = c;
		return NULL;
	}
}

static struct op *caselist(void)
{
	struct op *t;

	t = NULL;
	while ((peeksym = yylex(CONTIN)) != ESAC) {
		DBGPRINTF(("CASELIST, doing yylex, peeksym=%d\n", peeksym));
		t = list(t, casepart());
	}

	DBGPRINTF(("CASELIST, returning t=%p\n", t));
	return t;
}

static struct op *casepart(void)
{
	struct op *t;

	DBGPRINTF7(("CASEPART: enter...\n"));

	t = newtp();
	t->type = TPAT;
	t->words = pattern();
	musthave(')', 0);
	t->left = c_list();
	peeksym = yylex(CONTIN);
	if (peeksym != ESAC)
		musthave(BREAK, CONTIN);

	DBGPRINTF7(("CASEPART: made newtp(TPAT, t=%p)\n", t));

	return t;
}

static char **pattern(void)
{
	int c, cf;

	cf = CONTIN;
	do {
		musthave(WORD, cf);
		word(yylval.cp);
		cf = 0;
		c = yylex(0);
	} while (c == '|');
	peeksym = c;
	word(NOWORD);

	return copyw();
}

static char **wordlist(void)
{
	int c;

	c = yylex(0);
	if (c != IN) {
		peeksym = c;
		return NULL;
	}
	startl = 0;
	while ((c = yylex(0)) == WORD)
		word(yylval.cp);
	word(NOWORD);
	peeksym = c;
	return copyw();
}

/*
 * supporting functions
 */
static struct op *list(struct op *t1, struct op *t2)
{
	DBGPRINTF7(("LIST: enter, t1=%p, t2=%p\n", t1, t2));

	if (t1 == NULL)
		return t2;
	if (t2 == NULL)
		return t1;

	return block(TLIST, t1, t2, NOWORDS);
}

static struct op *block(int type, struct op *t1, struct op *t2, char **wp)
{
	struct op *t;

	DBGPRINTF7(("BLOCK: enter, type=%d (%s)\n", type, T_CMD_NAMES[type]));

	t = newtp();
	t->type = type;
	t->left = t1;
	t->right = t2;
	t->words = wp;

	DBGPRINTF7(("BLOCK: inserted %p between %p and %p\n", t, t1,
				t2));

	return t;
}

/* See if given string is a shell multiline (FOR, IF, etc) */
static int rlookup(char *n)
{
	const struct res *rp;

	DBGPRINTF7(("RLOOKUP: enter, n is %s\n", n));

	for (rp = restab; rp->r_name; rp++)
		if (strcmp(rp->r_name, n) == 0) {
			DBGPRINTF7(("RLOOKUP: match, returning %d\n", rp->r_val));
			return rp->r_val;	/* Return numeric code for shell multiline */
		}

	DBGPRINTF7(("RLOOKUP: NO match, returning 0\n"));
	return 0;					/* Not a shell multiline */
}

static struct op *newtp(void)
{
	struct op *t;

	t = (struct op *) tree(sizeof(*t));
	t->type = 0;
	t->words = NULL;
	t->ioact = NULL;
	t->left = NULL;
	t->right = NULL;
	t->str = NULL;

	DBGPRINTF3(("NEWTP: allocated %p\n", t));

	return t;
}

static struct op *namelist(struct op *t)
{
	DBGPRINTF7(("NAMELIST: enter, t=%p, type %s, iolist=%p\n", t,
				T_CMD_NAMES[t->type], iolist));

	if (iolist) {
		iolist = addword((char *) NULL, iolist);
		t->ioact = copyio();
	} else
		t->ioact = NULL;

	if (t->type != TCOM) {
		if (t->type != TPAREN && t->ioact != NULL) {
			t = block(TPAREN, t, NOBLOCK, NOWORDS);
			t->ioact = t->left->ioact;
			t->left->ioact = NULL;
		}
		return t;
	}

	word(NOWORD);
	t->words = copyw();

	return t;
}

static char **copyw(void)
{
	char **wd;

	wd = getwords(wdlist);
	wdlist = 0;
	return wd;
}

static void word(char *cp)
{
	wdlist = addword(cp, wdlist);
}

static struct ioword **copyio(void)
{
	struct ioword **iop;

	iop = (struct ioword **) getwords(iolist);
	iolist = 0;
	return iop;
}

static struct ioword *io(int u, int f, char *cp)
{
	struct ioword *iop;

	iop = (struct ioword *) tree(sizeof(*iop));
	iop->io_unit = u;
	iop->io_flag = f;
	iop->io_name = cp;
	iolist = addword((char *) iop, iolist);
	return iop;
}

static int yylex(int cf)
{
	int c, c1;
	int atstart;

	c = peeksym;
	if (c > 0) {
		peeksym = 0;
		if (c == '\n')
			startl = 1;
		return c;
	}

	nlseen = 0;
	atstart = startl;
	startl = 0;
	yylval.i = 0;
	e.linep = line;

/* MALAMO */
	line[LINELIM - 1] = '\0';

 loop:
	while ((c = my_getc(0)) == ' ' || c == '\t')	/* Skip whitespace */
		;

	switch (c) {
	default:
		if (any(c, "0123456789")) {
			c1 = my_getc(0);
			unget(c1);
			if (c1 == '<' || c1 == '>') {
				iounit = c - '0';
				goto loop;
			}
			*e.linep++ = c;
			c = c1;
		}
		break;

	case '#':					/* Comment, skip to next newline or End-of-string */
		while ((c = my_getc(0)) != '\0' && c != '\n');
		unget(c);
		goto loop;

	case 0:
		DBGPRINTF5(("YYLEX: return 0, c=%d\n", c));
		return c;

	case '$':
		DBGPRINTF9(("YYLEX: found $\n"));
		*e.linep++ = c;
		c = my_getc(0);
		if (c == '{') {
			c = collect(c, '}');
			if (c != '\0')
				return c;
			goto pack;
		}
		break;

	case '`':
	case '\'':
	case '"':
		c = collect(c, c);
		if (c != '\0')
			return c;
		goto pack;

	case '|':
	case '&':
	case ';':
		startl = 1;
		/* If more chars process them, else return NULL char */
		c1 = dual(c);
		if (c1 != '\0')
			return c1;
		return c;

	case '^':
		startl = 1;
		return '|';
	case '>':
	case '<':
		diag(c);
		return c;

	case '\n':
		nlseen++;
		gethere();
		startl = 1;
		if (multiline || cf & CONTIN) {
			if (interactive && e.iop <= iostack) {
#if ENABLE_FEATURE_EDITING
				current_prompt = cprompt->value;
#else
				prs(cprompt->value);
#endif
			}
			if (cf & CONTIN)
				goto loop;
		}
		return c;

	case '(':
	case ')':
		startl = 1;
		return c;
	}

	unget(c);

 pack:
	while ((c = my_getc(0)) != '\0' && !any(c, "`$ '\"\t;&<>()|^\n")) {
		if (e.linep >= elinep)
			err("word too long");
		else
			*e.linep++ = c;
	};

	unget(c);

	if (any(c, "\"'`$"))
		goto loop;

	*e.linep++ = '\0';

	if (atstart) {
		c = rlookup(line);
		if (c != 0) {
			startl = 1;
			return c;
		}
	}

	yylval.cp = strsave(line, areanum);
	return WORD;
}


static int collect(int c, int c1)
{
	char s[2];

	DBGPRINTF8(("COLLECT: enter, c=%d, c1=%d\n", c, c1));

	*e.linep++ = c;
	while ((c = my_getc(c1)) != c1) {
		if (c == 0) {
			unget(c);
			s[0] = c1;
			s[1] = 0;
			prs("no closing ");
			yyerror(s);
			return YYERRCODE;
		}
		if (interactive && c == '\n' && e.iop <= iostack) {
#if ENABLE_FEATURE_EDITING
			current_prompt = cprompt->value;
#else
			prs(cprompt->value);
#endif
		}
		*e.linep++ = c;
	}

	*e.linep++ = c;

	DBGPRINTF8(("COLLECT: return 0, line is %s\n", line));

	return 0;
}

/* "multiline commands" helper func */
/* see if next 2 chars form a shell multiline */
static int dual(int c)
{
	char s[3];
	char *cp = s;

	DBGPRINTF8(("DUAL: enter, c=%d\n", c));

	*cp++ = c;              /* c is the given "peek" char */
	*cp++ = my_getc(0);     /* get next char of input */
	*cp = '\0';             /* add EOS marker */

	c = rlookup(s);	        /* see if 2 chars form a shell multiline */
	if (c == 0)
		unget(*--cp);   /* String is not a shell multiline, put peek char back */

	return c;               /* String is multiline, return numeric multiline (restab) code */
}

static void diag(int ec)
{
	int c;

	DBGPRINTF8(("DIAG: enter, ec=%d\n", ec));

	c = my_getc(0);
	if (c == '>' || c == '<') {
		if (c != ec)
			zzerr();
		yylval.i = (ec == '>' ? IOWRITE | IOCAT : IOHERE);
		c = my_getc(0);
	} else
		yylval.i = (ec == '>' ? IOWRITE : IOREAD);
	if (c != '&' || yylval.i == IOHERE)
		unget(c);
	else
		yylval.i |= IODUP;
}

static char *tree(unsigned size)
{
	char *t;

	t = getcell(size);
	if (t == NULL) {
		DBGPRINTF2(("TREE: getcell(%d) failed!\n", size));
		prs("command line too complicated\n");
		fail();
		/* NOTREACHED */
	}
	return t;
}


/* VARARGS1 */
/* ARGSUSED */

/* -------- exec.c -------- */

static struct op **find1case(struct op *t, const char *w)
{
	struct op *t1;
	struct op **tp;
	char **wp;
	char *cp;

	if (t == NULL) {
		DBGPRINTF3(("FIND1CASE: enter, t==NULL, returning.\n"));
		return NULL;
	}

	DBGPRINTF3(("FIND1CASE: enter, t->type=%d (%s)\n", t->type,
				T_CMD_NAMES[t->type]));

	if (t->type == TLIST) {
		tp = find1case(t->left, w);
		if (tp != NULL) {
			DBGPRINTF3(("FIND1CASE: found one to the left, returning tp=%p\n", tp));
			return tp;
		}
		t1 = t->right;			/* TPAT */
	} else
		t1 = t;

	for (wp = t1->words; *wp;) {
		cp = evalstr(*wp++, DOSUB);
		if (cp && gmatch(w, cp)) {
			DBGPRINTF3(("FIND1CASE: returning &t1->left= %p.\n",
						&t1->left));
			return &t1->left;
		}
	}

	DBGPRINTF(("FIND1CASE: returning NULL\n"));
	return NULL;
}

static struct op *findcase(struct op *t, const char *w)
{
	struct op **tp;

	tp = find1case(t, w);
	return tp != NULL ? *tp : NULL;
}

/*
 * execute tree
 */

static int execute(struct op *t, int *pin, int *pout, int act)
{
	struct op *t1;
	volatile int i, rv, a;
	const char *cp;
	char **wp, **wp2;
	struct var *vp;
	struct op *outtree_save;
	struct brkcon bc;

#if __GNUC__
	/* Avoid longjmp clobbering */
	(void) &wp;
#endif

	if (t == NULL) {
		DBGPRINTF4(("EXECUTE: enter, t==null, returning.\n"));
		return 0;
	}

	DBGPRINTF(("EXECUTE: t=%p, t->type=%d (%s), t->words is %s\n", t,
			   t->type, T_CMD_NAMES[t->type],
			   ((t->words == NULL) ? "NULL" : t->words[0])));

	rv = 0;
	a = areanum++;
	wp = (wp2 = t->words) != NULL
		? eval(wp2, t->type == TCOM ? DOALL : DOALL & ~DOKEY)
		: NULL;

	switch (t->type) {
	case TDOT:
		DBGPRINTF3(("EXECUTE: TDOT\n"));

		outtree_save = outtree;

		newfile(evalstr(t->words[0], DOALL));

		t->left = dowholefile(TLIST, 0);
		t->right = NULL;

		outtree = outtree_save;

		if (t->left)
			rv = execute(t->left, pin, pout, 0);
		if (t->right)
			rv = execute(t->right, pin, pout, 0);
		break;

	case TPAREN:
		rv = execute(t->left, pin, pout, 0);
		break;

	case TCOM:
		rv = forkexec(t, pin, pout, act, wp);
		break;

	case TPIPE:
		{
			int pv[2];

			rv = openpipe(pv);
			if (rv < 0)
				break;
			pv[0] = remap(pv[0]);
			pv[1] = remap(pv[1]);
			(void) execute(t->left, pin, pv, 0);
			rv = execute(t->right, pv, pout, 0);
		}
		break;

	case TLIST:
		(void) execute(t->left, pin, pout, 0);
		rv = execute(t->right, pin, pout, 0);
		break;

	case TASYNC:
		{
			int hinteractive = interactive;

			DBGPRINTF7(("EXECUTE: TASYNC clause, calling vfork()...\n"));

			i = vfork();
			if (i == 0) { /* child */
				signal(SIGINT, SIG_IGN);
				signal(SIGQUIT, SIG_IGN);
				if (interactive)
					signal(SIGTERM, SIG_DFL);
				interactive = 0;
				if (pin == NULL) {
					close(0);
					xopen(bb_dev_null, O_RDONLY);
				}
				_exit(execute(t->left, pin, pout, FEXEC));
			}
			interactive = hinteractive;
			if (i != -1) {
				setval(lookup("!"), putn(i));
				if (pin != NULL)
					closepipe(pin);
				if (interactive) {
					prs(putn(i));
					prs("\n");
				}
			} else
				rv = -1;
			setstatus(rv);
		}
		break;

	case TOR:
	case TAND:
		rv = execute(t->left, pin, pout, 0);
		t1 = t->right;
		if (t1 != NULL && (rv == 0) == (t->type == TAND))
			rv = execute(t1, pin, pout, 0);
		break;

	case TFOR:
		if (wp == NULL) {
			wp = dolv + 1;
			i = dolc;
			if (i < 0)
				i = 0;
		} else {
			i = -1;
			while (*wp++ != NULL);
		}
		vp = lookup(t->str);
		while (setjmp(bc.brkpt))
			if (isbreak)
				goto broken;
		brkset(&bc);
		for (t1 = t->left; i-- && *wp != NULL;) {
			setval(vp, *wp++);
			rv = execute(t1, pin, pout, 0);
		}
		brklist = brklist->nextlev;
		break;

	case TWHILE:
	case TUNTIL:
		while (setjmp(bc.brkpt))
			if (isbreak)
				goto broken;
		brkset(&bc);
		t1 = t->left;
		while ((execute(t1, pin, pout, 0) == 0) == (t->type == TWHILE))
			rv = execute(t->right, pin, pout, 0);
		brklist = brklist->nextlev;
		break;

	case TIF:
	case TELIF:
		if (t->right != NULL) {
			rv = !execute(t->left, pin, pout, 0) ?
				execute(t->right->left, pin, pout, 0) :
				execute(t->right->right, pin, pout, 0);
		}
		break;

	case TCASE:
		cp = evalstr(t->str, DOSUB | DOTRIM);
		if (cp == NULL)
			cp = "";

		DBGPRINTF7(("EXECUTE: TCASE, t->str is %s, cp is %s\n",
					((t->str == NULL) ? "NULL" : t->str),
					((cp == NULL) ? "NULL" : cp)));

		t1 = findcase(t->left, cp);
		if (t1 != NULL) {
			DBGPRINTF7(("EXECUTE: TCASE, calling execute(t=%p, t1=%p)...\n", t, t1));
			rv = execute(t1, pin, pout, 0);
			DBGPRINTF7(("EXECUTE: TCASE, back from execute(t=%p, t1=%p)...\n", t, t1));
		}
		break;

	case TBRACE:
/*
		iopp = t->ioact;
		if (i)
			while (*iopp)
				if (iosetup(*iopp++, pin!=NULL, pout!=NULL)) {
					rv = -1;
					break;
				}
*/
		if (rv >= 0) {
			t1 = t->left;
			if (t1) {
				rv = execute(t1, pin, pout, 0);
			}
		}
		break;

	};

 broken:
	t->words = wp2;
	isbreak = 0;
	freehere(areanum);
	freearea(areanum);
	areanum = a;
	if (interactive && intr) {
		closeall();
		fail();
	}

	i = trapset;
	if (i != 0) {
		trapset = 0;
		runtrap(i);
	}

	DBGPRINTF(("EXECUTE: returning from t=%p, rv=%d\n", t, rv));
	return rv;
}

typedef int (*builtin_func_ptr)(struct op *);

static builtin_func_ptr inbuilt(const char *s)
{
	const struct builtincmd *bp;

	for (bp = builtincmds; bp->name; bp++)
		if (strcmp(bp->name, s) == 0)
			return bp->builtinfunc;
	return NULL;
}

static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp)
{
	pid_t newpid;
	int i, rv;
	builtin_func_ptr shcom = NULL;
	int f;
	const char *cp = NULL;
	struct ioword **iopp;
	int resetsig;
	char **owp;
	int forked = 0;

	int *hpin = pin;
	int *hpout = pout;
	char *hwp;
	int hinteractive;
	int hintr;
	struct brkcon *hbrklist;
	int hexecflg;

#if __GNUC__
	/* Avoid longjmp clobbering */
	(void) &pin;
	(void) &pout;
	(void) &wp;
	(void) &shcom;
	(void) &cp;
	(void) &resetsig;
	(void) &owp;
#endif

	DBGPRINTF(("FORKEXEC: t=%p, pin %p, pout %p, act %d\n", t, pin,
			   pout, act));
	DBGPRINTF7(("FORKEXEC: t->words is %s\n",
				((t->words == NULL) ? "NULL" : t->words[0])));

	owp = wp;
	resetsig = 0;
	rv = -1;					/* system-detected error */
	if (t->type == TCOM) {
		while (*wp++ != NULL)
			continue;
		cp = *wp;

		/* strip all initial assignments */
		/* not correct wrt PATH=yyy command  etc */
		if (FLAG['x']) {
			DBGPRINTF9(("FORKEXEC: echo'ing, cp=%p, wp=%p, owp=%p\n",
						cp, wp, owp));
			echo(cp ? wp : owp);
		}

		if (cp == NULL && t->ioact == NULL) {
			while ((cp = *owp++) != NULL && assign(cp, COPYV))
				continue;
			DBGPRINTF(("FORKEXEC: returning setstatus()\n"));
			return setstatus(0);
		}
		if (cp != NULL) {
			shcom = inbuilt(cp);
		}
	}

	t->words = wp;
	f = act;

	DBGPRINTF(("FORKEXEC: shcom %p, f&FEXEC 0x%x, owp %p\n", shcom,
			   f & FEXEC, owp));

	if (shcom == NULL && (f & FEXEC) == 0) {
		/* Save values in case the child process alters them */
		hpin = pin;
		hpout = pout;
		hwp = *wp;
		hinteractive = interactive;
		hintr = intr;
		hbrklist = brklist;
		hexecflg = execflg;

		DBGPRINTF3(("FORKEXEC: calling vfork()...\n"));

		newpid = vfork();

		if (newpid == -1) {
			DBGPRINTF(("FORKEXEC: ERROR, cannot vfork()!\n"));
			return -1;
		}

		if (newpid > 0) {  /* Parent */
			/* Restore values */
			pin = hpin;
			pout = hpout;
			*wp = hwp;
			interactive = hinteractive;
			intr = hintr;
			brklist = hbrklist;
			execflg = hexecflg;
/* moved up
			if (i == -1)
				return rv;
*/
			if (pin != NULL)
				closepipe(pin);

			return (pout == NULL ? setstatus(waitfor(newpid, 0)) : 0);
		}

		/* Must be the child process, pid should be 0 */
		DBGPRINTF(("FORKEXEC: child process, shcom=%p\n", shcom));

		if (interactive) {
			signal(SIGINT, SIG_IGN);
			signal(SIGQUIT, SIG_IGN);
			resetsig = 1;
		}
		interactive = 0;
		intr = 0;
		forked = 1;
		brklist = 0;
		execflg = 0;
	}

	if (owp != NULL)
		while ((cp = *owp++) != NULL && assign(cp, COPYV))
			if (shcom == NULL)
				export(lookup(cp));

#ifdef COMPIPE
	if ((pin != NULL || pout != NULL) && shcom != NULL && shcom != doexec) {
		err("piping to/from shell builtins not yet done");
		if (forked)
			_exit(-1);
		return -1;
	}
#endif

	if (pin != NULL) {
		xmove_fd(pin[0], 0);
		if (pin[1] != 0) close(pin[1]);
	}
	if (pout != NULL) {
		xmove_fd(pout[1], 1);
		if (pout[1] != 1) close(pout[0]);
	}

	iopp = t->ioact;
	if (iopp != NULL) {
		if (shcom != NULL && shcom != doexec) {
			prs(cp);
			err(": cannot redirect shell command");
			if (forked)
				_exit(-1);
			return -1;
		}
		while (*iopp)
			if (iosetup(*iopp++, pin != NULL, pout != NULL)) {
				if (forked)
					_exit(rv);
				return rv;
			}
	}

	if (shcom) {
		i = setstatus((*shcom) (t));
		if (forked)
			_exit(i);
		DBGPRINTF(("FORKEXEC: returning i=%d\n", i));
		return i;
	}

	/* should use FIOCEXCL */
	for (i = FDBASE; i < NOFILE; i++)
		close(i);
	if (resetsig) {
		signal(SIGINT, SIG_DFL);
		signal(SIGQUIT, SIG_DFL);
	}

	if (t->type == TPAREN)
		_exit(execute(t->left, NOPIPE, NOPIPE, FEXEC));
	if (wp[0] == NULL)
		_exit(0);

	cp = rexecve(wp[0], wp, makenv(0, NULL));
	prs(wp[0]);
	prs(": ");
	err(cp);
	if (!execflg)
		trap[0] = NULL;

	DBGPRINTF(("FORKEXEC: calling leave(), pid=%d\n", newpid));

	leave();
	/* NOTREACHED */
	_exit(1);
}

/*
 * 0< 1> are ignored as required
 * within pipelines.
 */
static int iosetup(struct ioword *iop, int pipein, int pipeout)
{
	int u = -1;
	char *cp = NULL;
	const char *msg;

	DBGPRINTF(("IOSETUP: iop %p, pipein %i, pipeout %i\n", iop,
			   pipein, pipeout));

	if (iop->io_unit == IODEFAULT)	/* take default */
		iop->io_unit = iop->io_flag & (IOREAD | IOHERE) ? 0 : 1;

	if (pipein && iop->io_unit == 0)
		return 0;

	if (pipeout && iop->io_unit == 1)
		return 0;

	msg = iop->io_flag & (IOREAD | IOHERE) ? "open" : "create";
	if ((iop->io_flag & IOHERE) == 0) {
		cp = iop->io_name; /* huh?? */
		cp = evalstr(cp, DOSUB | DOTRIM);
		if (cp == NULL)
			return 1;
	}

	if (iop->io_flag & IODUP) {
		if (cp[1] || (!isdigit(*cp) && *cp != '-')) {
			prs(cp);
			err(": illegal >& argument");
			return 1;
		}
		if (*cp == '-')
			iop->io_flag = IOCLOSE;
		iop->io_flag &= ~(IOREAD | IOWRITE);
	}
	switch (iop->io_flag) {
	case IOREAD:
		u = open(cp, O_RDONLY);
		break;

	case IOHERE:
	case IOHERE | IOXHERE:
		u = herein(iop->io_name, iop->io_flag & IOXHERE);
		cp = (char*)"here file";
		break;

	case IOWRITE | IOCAT:
		u = open(cp, O_WRONLY);
		if (u >= 0) {
			lseek(u, (long) 0, SEEK_END);
			break;
		}
	case IOWRITE:
		u = creat(cp, 0666);
		break;

	case IODUP:
		u = dup2(*cp - '0', iop->io_unit);
		break;

	case IOCLOSE:
		close(iop->io_unit);
		return 0;
	}
	if (u < 0) {
		prs(cp);
		prs(": cannot ");
		warn(msg);
		return 1;
	}
	if (u != iop->io_unit) {
		dup2(u, iop->io_unit);
		close(u);
	}
	return 0;
}

/*
 * Enter a new loop level (marked for break/continue).
 */
static void brkset(struct brkcon *bc)
{
	bc->nextlev = brklist;
	brklist = bc;
}

/*
 * Wait for the last process created.
 * Print a message for each process found
 * that was killed by a signal.
 * Ignore interrupt signals while waiting
 * unless `canintr' is true.
 */
static int waitfor(int lastpid, int canintr)
{
	int pid, rv;
	int s;
	int oheedint = heedint;

	heedint = 0;
	rv = 0;
	do {
		pid = wait(&s);
		if (pid == -1) {
			if (errno != EINTR || canintr)
				break;
		} else {
			rv = WAITSIG(s);
			if (rv != 0) {
				if (rv < ARRAY_SIZE(signame)) {
					if (signame[rv] != NULL) {
						if (pid != lastpid) {
							prn(pid);
							prs(": ");
						}
						prs(signame[rv]);
					}
				} else {
					if (pid != lastpid) {
						prn(pid);
						prs(": ");
					}
					prs("Signal ");
					prn(rv);
					prs(" ");
				}
				if (WAITCORE(s))
					prs(" - core dumped");
				if (rv >= ARRAY_SIZE(signame) || signame[rv])
					prs("\n");
				rv = -1;
			} else
				rv = WAITVAL(s);
		}
	} while (pid != lastpid);
	heedint = oheedint;
	if (intr) {
		if (interactive) {
			if (canintr)
				intr = 0;
		} else {
			if (exstat == 0)
				exstat = rv;
			onintr(0);
		}
	}
	return rv;
}

static int setstatus(int s)
{
	exstat = s;
	setval(lookup("?"), putn(s));
	return s;
}

/*
 * PATH-searching interface to execve.
 * If getenv("PATH") were kept up-to-date,
 * execvp might be used.
 */
static const char *rexecve(char *c, char **v, char **envp)
{
	int i;
	const char *sp;
	char *tp;
	int eacces = 0, asis = 0;
	char *name = c;

	if (ENABLE_FEATURE_SH_STANDALONE) {
		if (find_applet_by_name(name)) {
			/* We have to exec here since we vforked.  Running
			 * run_applet_and_exit() won't work and bad things
			 * will happen. */
			execve(bb_busybox_exec_path, v, envp);
		}
	}

	DBGPRINTF(("REXECVE: c=%p, v=%p, envp=%p\n", c, v, envp));

	sp = any('/', c) ? "" : path->value;
	asis = (*sp == '\0');
	while (asis || *sp != '\0') {
		asis = 0;
		tp = e.linep;
		for (; *sp != '\0'; tp++) {
			*tp = *sp++;
			if (*tp == ':') {
				asis = (*sp == '\0');
				break;
			}
		}
		if (tp != e.linep)
			*tp++ = '/';
		for (i = 0; (*tp++ = c[i++]) != '\0';);

		DBGPRINTF3(("REXECVE: e.linep is %s\n", e.linep));

		execve(e.linep, v, envp);

		switch (errno) {
		case ENOEXEC:
			*v = e.linep;
			tp = *--v;
			*v = e.linep;
			execve(DEFAULT_SHELL, v, envp);
			*v = tp;
			return "no Shell";

		case ENOMEM:
			return (char *) bb_msg_memory_exhausted;