msh.c

来自「手机嵌入式Linux下可用的busybox源码」· C语言 代码 · 共 3,606 行 · 第 1/5 页

static int dolabel(void);
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, void (*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) (), int key);
static void badid(char *s);
static int doset(struct op *t);
static void varput(char *s, int out);
static int dotimes(void);

int execute(t, pin, pout, act)
register struct op *t;
int *pin, *pout;
int act;
{
	register struct op *t1;
	int i, pv[2], rv, child, a;
	char *cp, **wp, **wp2;
	struct var *vp;
	struct brkcon bc;

#if __GNUC__
	/* Avoid longjmp clobbering */
	(void) &i;
	(void) &rv;
	(void) ℘
#endif

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

	switch (t->type) {
	case TPAREN:
	case TCOM:
		rv = forkexec(t, pin, pout, act, wp, &child);
		if (child) {
			exstat = rv;
			leave();
		}
		break;

	case TPIPE:
		if ((rv = openpipe(pv)) < 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:
	{
	        /* save global vars altered by child */
		int hinteractive = interactive;

		i = parent();
		if (i != 0) {
		        /* restore global vars */
			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);
		} else {
			signal(SIGINT, SIG_IGN);
			signal(SIGQUIT, SIG_IGN);
			if (interactive)
				signal(SIGTERM, SIG_DFL);
			interactive = 0;
			if (pin == NULL) {
				close(0);
				open("/dev/null", 0);
			}
			_exit(execute(t->left, pin, pout, FEXEC));
		}
		break;
	}
	case TOR:
	case TAND:
		rv = execute(t->left, pin, pout, 0);
		if ((t1 = t->right) != NULL && (rv == 0) == (t->type == TAND))
			rv = execute(t1, pin, pout, 0);
		break;

	case TFOR:
		if (wp == NULL) {
			wp = dolv + 1;
			if ((i = dolc) < 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:
		if ((cp = evalstr(t->str, DOSUB | DOTRIM)) == 0)
			cp = "";
		if ((t1 = findcase(t->left, cp)) != NULL)
			rv = execute(t1, pin, pout, 0);
		break;

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

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

static int forkexec(t, pin, pout, act, wp, pforked)
register struct op *t;
int *pin, *pout;
int act;
char **wp;
int *pforked;
{
	int i, rv, (*shcom) ();
	register int f;
	char *cp = NULL;
	struct ioword **iopp;
	int resetsig;
	char **owp;

	int *hpin = pin;
	int *hpout = pout;
	int hforked;
	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	

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

		/* strip all initial assignments */
		/* not correct wrt PATH=yyy command  etc */
		if (flag['x'])
			echo(cp ? wp : owp);
		if (cp == NULL && t->ioact == NULL) {
			while ((cp = *owp++) != NULL && assign(cp, COPYV));
			return (setstatus(0));
		} else if (cp != NULL)
			shcom = inbuilt(cp);
	}
	t->words = wp;
	f = act;
	if (shcom == NULL && (f & FEXEC) == 0) {

	        /* save vars altered by child (needed by vfork) */
		hpin = pin;
		hpout = pout;
		hforked = *pforked;
		hwp = *wp;
		hinteractive = interactive;
		hintr = intr;
		hbrklist = brklist;
		hexecflg = execflg;
	
		i = parent();
		if (i != 0) {
		        /* restore vars altered by child (needed by vfork) */
			pin = hpin;
			pout = hpout;
			*pforked = hforked;
			*wp = hwp;
			interactive = hinteractive;
			intr = hintr;
			brklist = hbrklist;
			execflg = hexecflg;

			*pforked = 0;
			if (i == -1)
				return (rv);
			if (pin != NULL)
				closepipe(pin);
			return (pout == NULL ? setstatus(waitfor(i, 0)) : 0);
		}
		if (interactive) {
			signal(SIGINT, SIG_IGN);
			signal(SIGQUIT, SIG_IGN);
			resetsig = 1;
		}
		interactive = 0;
		intr = 0;
		(*pforked)++;
		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");
		return (-1);
	}
#endif
	if (pin != NULL) {
		dup2(pin[0], 0);
		closepipe(pin);
	}
	if (pout != NULL) {
		dup2(pout[1], 1);
		closepipe(pout);
	}
	if ((iopp = t->ioact) != NULL) {
		if (shcom != NULL && shcom != doexec) {
			prs(cp);
			err(": cannot redirect shell command");
			return (-1);
		}
		while (*iopp)
			if (iosetup(*iopp++, pin != NULL, pout != NULL))
				return (rv);
	}
	if (shcom)
		return (setstatus((*shcom) (t)));
	/* 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));
	prs(wp[0]);
	prs(": ");
	warn(cp);
	if (!execflg)
		trap[0] = NULL;
#ifdef __uClinux__
	_exit(1);
#else
	leave();
#endif
	/* NOTREACHED */
}

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

	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;
		if ((cp = evalstr(cp, DOSUB | DOTRIM)) == NULL)
			return (1);
	}
	if (iop->io_flag & IODUP) {
		if (cp[1] || (!digit(*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, 0);
		break;

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

	case IOWRITE | IOCAT:
		if ((u = open(cp, 1)) >= 0) {
			lseek(u, (long) 0, 2);
			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);
	default:
		u = -1;
		break;
	}
	if (u < 0) {
		int sav_err = errno;

		prs(cp);
		if (iop->io_flag & IOHERE)
			prs(iop->io_name);
		prs(": cannot ");
		prs(msg);
		prs(" (");
		prs(strerror(sav_err));
		warn(")");
		return (1);
	} else {
		if (u != iop->io_unit) {
			dup2(u, iop->io_unit);
			close(u);
		}
	}
	return (0);
}

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

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

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

	if (t == NULL)
		return ((struct op **) NULL);
	if (t->type == TLIST) {
		if ((tp = find1case(t->left, w)) != NULL)
			return (tp);
		t1 = t->right;			/* TPAT */
	} else
		t1 = t;
	for (wp = t1->words; *wp;)
		if ((cp = evalstr(*wp++, DOSUB)) && gmatch(w, cp))
			return (&t1->left);
	return ((struct op **) NULL);
}

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

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

/*
 * Enter a new loop level (marked for break/continue).
 */
static void brkset(bc)
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.
 */
int waitfor(lastpid, canintr)
register int lastpid;
int canintr;
{
	register 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 {
			if ((rv = WAITSIG(s)) != 0) {
				if (rv < NSIGNAL) {
					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 >= NSIGNAL || 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);
}

int setstatus(s)
register 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.
 */
char *rexecve(c, v, envp)
char *c, **v, **envp;
{
	register int i;
	register char *sp, *tp;
	int eacces = 0, asis = 0;

#ifdef BB_FEATURE_SH_STANDALONE_SHELL
	char *name = c;
#ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
	name = get_last_path_component(name);
#endif
	optind = 1;
	if (find_applet_by_name(name)) {
		/* We have to exec here since we vforked.  Running 
		 * run_applet_by_name() won't work and bad things
		 * will happen. */
		execve("/proc/self/exe", v, envp);
		execve("busybox", v, envp);
	}
#endif

	sp = any('/', c)? "": path->value;
	asis = *sp == '\0';
	while (asis || *sp != '\0') {
		asis = 0;
		tp = e.linep;
		for (; *sp != '\0'; tp++)
			if ((*tp = *sp++) == ':') {
				asis = *sp == '\0';
				break;
			}
		if (tp != e.linep)
			*tp++ = '/';
		for (i = 0; (*tp++ = c[i++]) != '\0';);
		execve(e.linep, v, envp);
		switch (errno) {
		case ENOEXEC:
			*v = e.linep;
			tp = *--v;
			*v = e.linep;
			execve("/bin/sh", v, envp);
			*v = tp;
			return ("no Shell");

		case ENOMEM:
			return ("program too big");

		case E2BIG:
			return ("argument list too long");

		case EACCES:
			eacces++;
			break;
		}
	}
	return (errno == ENOENT ? "not found" : "cannot execute");
}

/*
 * Run the command produced by generator `f'
 * applied to stream `arg'.
 */
int run(argp, f)
struct ioarg *argp;
int (*f) ();
{
	struct op *otree;
	struct wdblock *swdlist;
	struct wdblock *siolist;
	jmp_buf ev, rt;
	xint *ofail;
	int rv;

#if __GNUC__
	/* Avoid longjmp clobbering */
	(void) &rv;
#endif
	areanum++;
	swdlist = wdlist;
	siolist = iolist;
	otree = outtree;
	ofail = failpt;
	rv = -1;
	if (newenv(setjmp(errpt = ev)) == 0) {
		wdlist = 0;
		iolist = 0;
		pushio(argp, f);
		e.iobase = e.iop;
		yynerrs = 0;
		if (setjmp(failpt = rt) == 0 && yyparse() == 0)
			rv = execute(outtree, NOPIPE, NOPIPE, 0);
		quitenv();
	}
	wdlist = swdlist;
	iolist = siolist;
	failpt = ofail;
	outtree = otree;
	freearea(areanum--);
	return (rv);
}

/* -------- do.c -------- */

/*
 * built-in commands: doX
 */

static int
dolabel()
{
	return (0);
}

static int
dochdir(t)
register struct op *t;
{
	register char *cp, *er;

	if ((cp = t->words[1]) == NULL && (cp = homedir->value) == NULL)
		er = ": no home directory";
	else if (chdir(cp) < 0)
		er = ": bad directory";
	else {
#ifdef TEST_NEW_VERSION
#ifdef BB_FEATURE_SH_FANCY_PROMPT
		char *cated = NULL;

		if (*cp != '/')
			cp = cated = concat_path_file(cwd, cp);
		if (cwd != unknown)
			free(cwd);
		cwd = simplify_path(cp);
		free(cated);
#endif
#endif
		return (0);
	}
	prs(cp != NULL ? cp : "cd");
	err(er);
	return (1);
}

int doshift(t)
register struct op *t;
{
	int n;

	n = t->words[1] ? getn(t->words[1]) : 1;
	if (dolc < n) {
		err("nothing to shift");
		return (1);
	}