msh.c

shell-HHARM9200.rar 华恒 AT91rm9200 中Busybox shell的源代码

/* 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 <[e-mail]>
 *
 * - backtick expansion did not work properly
 *   Jonas Holmberg <[e-mail]>
 *   Robert Schwebel <[e-mail]>
 *   Erik Andersen <[e-mail]>
 *
 * 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
 *
 * Original copyright notice is retained at the end of this file.
 */

#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <setjmp.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/times.h>
#include <sys/types.h>
#include <sys/wait.h>

#include "cmdedit.h"
#include "busybox.h"


/* -------- 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 defintions
 */
typedef void xint;	/* base type of jmp_buf, for not broken compilers */

/*
 * shell components
 */

#define	QUOTE	0200

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

/*
 * 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 & */

/*
 * actions determining the environment of a process
 */
#define	BIT(i)	(1<<(i))
#define	FEXEC	BIT(0)	/* execute without forking */

/*
 * 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)

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 int newfile(char *s);
static char *findeq(char *cp);
static char *cclass(char *p, int sub);
static void initarea(void);
extern int msh_main(int argc, char **argv);


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

/*
 * 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 */

static	struct	wdblock	*wdlist;
static	struct	wdblock	*iolist;

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

/*
 * 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	*flag;

static	char	*null;	/* null value for variable */
static	int	intr;	/* interrupt pending */

static	char	*trap[_NSIG+1];
static	char	ourtrap[_NSIG+1];
static	int	trapset;	/* trap pending */

static	int	heedint;	/* heed interrupt signals */

static	int	yynerrs;	/* yacc */

static	char	line[LINELIM];
static	char	*elinep;

/*
 * other functions
 */
static int(*inbuilt(char *s))(struct op *);


static char *rexecve (char *c , char **v, char **envp );
static char *space (int n );
static char *strsave (char *s, int a );
static char *evalstr (char *cp, int f );
static char *putn (int n );
static char *itoa (int n );
static char *unquote (char *as );
static struct var *lookup (char *n );
static int rlookup (char *n );
static struct wdblock *glob (char *cp, struct wdblock *wb );
static int my_getc( int ec);
static int subgetc (int ec, int quoted );
static char **makenv (void);
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 err (char *s );
static int anys (char *s1, char *s2 );
static int any (int c, char *s );
static void next (int f );
static void setdash (void);
static void onecommand (void);
static void runtrap (int i );
static int gmatch (char *s, char *p );

/*
 * error handling
 */
static void leave (void); /* abort shell (or fail in subshell) */
static void fail (void);	 /* fail but return to process next command */
static void warn (char *s );
static void sig (int i );	 /* default signal handler */



/* -------- 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
#define	YYERRCODE 300

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

#define	SYNTAXERR	zzerr()
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 void zzerr(void);
static void yyerror(char *s );
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	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 yyparse (void);
static struct var *lookup (char *n );
static void setval (struct var *vp, char *val );
static void nameval (struct var *vp, char *val, char *name );
static void export (struct var *vp );
static void ronly (struct var *vp );
static int isassign (char *s );
static int checkname (char *cp );
static int assign (char *s, int cf );
static void putvlist (int f, int out );
static int eqname (char *n1, char *n2 );

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

/* -------- 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 {
	char	*aword;
	char	**awordlist;
	int	afile;		/* file descriptor */
	unsigned afid;		/* buffer id */
	long	afpos;		/* file position */
	struct iobuf *afbuf;	/* buffer for this file */
};
//static struct ioarg ioargstack[NPUSH];
#define AFID_NOBUF	(~0)
#define AFID_ID		0

/* 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 */
};
//static	struct	io	iostack[NPUSH];
#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)

/*
 * 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 *));

/*
 * IO functions
 */
static int eofc (void);
static int readc (void);
static void unget (int c );
static void ioecho (int c );
static void prs (char *s );
static void prn (unsigned u );
static void closef (int i );
static void closeall (void);

/*
 * IO control
 */
static void pushio (struct ioarg *argp, int (*f)(struct ioarg *));
static int remap (int fd );
static int openpipe (int *pv );
static void closepipe (int *pv );
static struct io *setbase (struct io *ip );

static	struct	ioarg	temparg;	/* temporary for PUSHIO */
#define	PUSHIO(what,arg,gen) ((temparg.what = (arg)),pushio(&temparg,(gen)))
#define	RUN(what,arg,gen) ((temparg.what = (arg)), run(&temparg,(gen)))

/* -------- 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 );

/* -------- area.h -------- */

/*
 * storage allocation
 */
static char *getcell (unsigned nbytes );
static void garbage (void);
static void setarea (char *cp, int a );
static int getarea (char *cp );
static void freearea (int a );
static void freecell (char *cp );
static	int	areanum;	/* current allocation area */

#define	NEW(type) (type *)getcell(sizeof(type))
#define	DELETE(obj)	freecell((char *)obj)


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

static int forkexec (struct op *t, int *pin, int *pout, int act, char **wp, int *pforked );
static int iosetup (struct ioword *iop, int pipein, int pipeout );
static void echo(char **wp );
static struct op **find1case (struct op *t, char *w );
static struct op *findcase (struct op *t, char *w );
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 (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 int a1, int a2, int (*a3)(char *, char *));
static void glob1 (char *base, char *lim );
static void glob2 (char *i, char *j );
static void glob3 (char *i, char *j, char *k );
static void readhere (char **name, char *s, int ec );
static void pushio (struct ioarg *argp, int (*f)(struct ioarg *));
static int xxchar(struct ioarg *ap );

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

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

struct res {
	char *r_name;
	int	  r_val;
};
static 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},
    {"{",		'{'},
    {"}",		'}'},
    {0,		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},
    {0,0}
};

/* Globals */
extern	char	**environ;	/* environment pointer */
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;
static char	*trap[_NSIG+1];
static char	ourtrap[_NSIG+1];
static int	trapset;	/* trap pending */
static int	yynerrs;	/* yacc */
static char	line[LINELIM];
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 struct	ioarg ioargstack[NPUSH];
static struct	io	iostack[NPUSH];
static int	areanum;	/* current allocation area */
static int	intr;
static int	inparse;
static char	flags['z'-'a'+1];
static char	*flag = flags-'a';
static char	*elinep = line+sizeof(line)-5;
static char	*null	= "";
static int	heedint =1;
static struct env e ={line, iostack, iostack-1, (xint *)NULL, FDBASE, (struct env *)NULL};
static void (*qflag)(int) = SIG_IGN;
static	int	startl;
static	int	peeksym;
static	int	nlseen;
static	int	iounit = IODEFAULT;
static	YYSTYPE	yylval;
static struct iobuf sharedbuf = {AFID_NOBUF};
static struct iobuf mainbuf = {AFID_NOBUF};
static unsigned bufid = AFID_ID;	/* buffer id counter */
static struct ioarg temparg = {0, 0, 0, AFID_NOBUF, 0};
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;


#ifdef CONFIG_FEATURE_COMMAND_EDITING
static char * current_prompt;
#endif

/* -------- sh.c -------- */
/*
 * shell
 */


extern int msh_main(int argc, char **argv)
{
	register int f;
	register char *s;
	int cflag;
	char *name, **ap;
	int (*iof)(struct ioarg *);

	initarea();
	if ((ap = environ) != NULL) {
		while (*ap)
			assign(*ap++, !COPYV);
		for (ap = environ; *ap;)
			export(lookup(*ap++));
	}
	closeall();
	areanum = 1;

	shell = lookup("SHELL");