sh.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 1,098 行 · 第 1/2 页

	 * We could avoid the critical region by grouping all the stuff
	 * in a single structure and pointing at it to move it all at
	 * once.  This is less efficient globally on many variable references
	 * however.
	 */
	getexit(oldexit);
	reenter = 0;
	if (setintr)
		omask = sigblock(sigmask(SIGINT));
	setexit();
	reenter++;
	if (reenter == 1) {
		/* Setup the new values of the state stuff saved above */
		copy((char *)&saveB, (char *)&B, sizeof saveB);
		fbuf = (char **) 0;
		fseekp = feobp = fblocks = 0;
		oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
		intty = isatty(SHIN), whyles = 0, gointr = 0;
		evalvec = 0; evalp = 0;
		enterhist = hflg;
		if (enterhist)
			HIST = '\0';
		/*
		 * Now if we are allowing commands to be interrupted,
		 * we let ourselves be interrupted.
		 */
		if (setintr)
			(void) sigsetmask(omask);
#ifdef TELL
		settell();
#endif
		process(0);		/* 0 -> blow away on errors */
	}
	if (setintr)
		(void) sigsetmask(omask);
	if (oSHIN >= 0) {
		register int i;

		/* We made it to the new state... free up its storage */
		/* This code could get run twice but xfree doesn't care */
		for (i = 0; i < fblocks; i++)
			xfree(fbuf[i]);
		xfree((char *)fbuf);

		/* Reset input arena */
		copy((char *)&B, (char *)&saveB, sizeof B);

		(void) close(SHIN), SHIN = oSHIN;
		arginp = oarginp, onelflg = oonelflg;
		evalp = oevalp, evalvec = oevalvec;
		intty = oldintty, whyles = oldwhyl, gointr = ogointr;
		if (enterhist)
			HIST = OHIST;
		enterhist = oenterhist;
#ifdef TELL
		cantell = otell;
#endif
	}

	resexit(oldexit);
	/*
	 * If process reset() (effectively an unwind) then
	 * we must also unwind.
	 */
	if (reenter >= 2)
		error(NOSTR);
}

rechist()
{
	char buf[BUFSIZ];
	int fp, ftmp, oldidfds;

	if (!fast) {
		if (value("savehist")[0] == '\0')
			return;
		(void) strcpy(buf, value("home"));
		(void) strcat(buf, "/.history");
		fp = creat(buf, 0666);
		if (fp == -1)
			return;
		oldidfds = didfds;
		didfds = 0;
		ftmp = SHOUT;
		SHOUT = fp;
		(void) strcpy(buf, value("savehist"));
		dumphist[2] = buf;
		dohist(dumphist);
		(void) close(fp);
		SHOUT = ftmp;
		didfds = oldidfds;
	}
}

goodbye()
{
	if (loginsh) {
		(void) signal(SIGQUIT, SIG_IGN);
		(void) signal(SIGINT, SIG_IGN);
		(void) signal(SIGTERM, SIG_IGN);
		setintr = 0;		/* No interrupts after "logout" */
		if (adrof("home"))
			srccat(value("home"), "/.logout");
	}
	rechist();
	exitstat();
}

exitstat()
{
#ifdef PROF
	monitor(0);
#endif

	/*
	 * Note that if STATUS is corrupted (i.e. getn bombs)
	 * then error will exit directly because we poke child here.
	 * Otherwise we might continue unwarrantedly (sic).
	 */
	child++;
	exit(getn(value("status")));
}

/*
 * in the event of a HUP we want to save the history
 */
phup()
{
	rechist();
	exit(1);
}

char	*jobargv[2] = { "jobs", 0 };
/*
 * Catch an interrupt, e.g. during lexical input.
 * If we are an interactive shell, we reset the interrupt catch
 * immediately.  In any case we drain the shell output,
 * and finally go through the normal error mechanism, which
 * gets a chance to make the shell go away.
 */
pintr()
{
	pintr1(1);
}

pintr1(wantnl)
	bool wantnl;
{
	register char **v;
	int omask;

	omask = sigblock(0);
	if (setintr) {
		(void) sigsetmask(omask & ~sigmask(SIGINT));
		if (pjobs) {
			pjobs = 0;
			csh_printf("\n");		/* 005 RNF */
			dojobs(jobargv);
			bferr("Interrupted");
		}
	}
	(void) sigsetmask(omask & ~sigmask(SIGCHLD));
	draino();

	/*
	 * If we have an active "onintr" then we search for the label.
	 * Note that if one does "onintr -" then we shan't be interruptible
	 * so we needn't worry about that here.
	 */
	if (gointr) {
		search(ZGOTO, 0, gointr);
		timflg = 0;
		if (v = pargv)
			pargv = 0, blkfree(v);
		if (v = gargv)
			gargv = 0, blkfree(v);
		reset();
	} else if (intty && wantnl)
		csh_printf("\n");/* 005 RNF */	/* Some like this, others don't */
	error(NOSTR);
}

/*
 * Process is the main driving routine for the shell.
 * It runs all command processing, except for those within { ... }
 * in expressions (which is run by a routine evalav in sh.exp.c which
 * is a stripped down process), and `...` evaluation which is run
 * also by a subset of this code in sh.glob.c in the routine backeval.
 *
 * The code here is a little strange because part of it is interruptible
 * and hence freeing of structures appears to occur when none is necessary
 * if this is ignored.
 *
 * Note that if catch is not set then we will unwind on any error.
 * If an end-of-file occurs, we return.
 */
process(catch)
	bool catch;
{
	jmp_buf osetexit;
	register struct command *t;

	getexit(osetexit);
	for (;;) {
		pendjob();
		paraml.next = paraml.prev = &paraml;
		paraml.word = "";
		t = 0;
		setexit();
		justpr = enterhist;	/* execute if not entering history */
#ifdef CSHEDIT
		editline = 0;		/* clear flag */
#endif

		/*
		 * Interruptible during interactive reads
		 */
		if (setintr)
			(void) sigsetmask(sigblock(0) & ~sigmask(SIGINT));

		/*
		 * For the sake of reset()
		 */
		freelex(&paraml), freesyn(t), t = 0;

		if (haderr) {
			if (!catch) {
				/* unwind */
				doneinp = 0;
				resexit(osetexit);
				reset();
			}
			haderr = 0;
			/*
			 * Every error is eventually caught here or
			 * the shell dies.  It is at this
			 * point that we clean up any left-over open
			 * files, by closing all but a fixed number
			 * of pre-defined files.  Thus routines don't
			 * have to worry about leaving files open due
			 * to deeper errors... they will get closed here.
			 */
			closem();
			continue;
		}
		if (doneinp) {
			doneinp = 0;
			break;
		}
		if (chkstop)
			chkstop--;
		if (neednote)
			pnote();
		if (intty && prompt && evalvec == 0) {
			mailchk();
			/*
			 * If we are at the end of the input buffer
			 * then we are going to read fresh stuff.
			 * Otherwise, we are rereading input and don't
			 * need or want to prompt.
			 */
			if (fseekp == feobp)
			    printprompt();
			flush();
		}
		err = 0;
		/*
		 * Initialize the last event here so that relative history
		 * accesses (ie !$ !*) remain relative.
		 */
		lastev = eventno;
		/*
		 * Echo not only on VERBOSE, but also with history expansion.
		 * If there is a lexical error then we forego history echo.
		 * If :v option was given (for edit) then skip echo.
		 */
#ifdef CSHEDIT
		if (lex(&paraml, 0) && !err && intty && !editline ||
		    adrof("verbose")) {
#else
		if (lex(&paraml) && !err && intty ||
		    adrof("verbose")) {
#endif
			haderr = 1;
			prlex(&paraml);
			haderr = 0;
		}

#ifdef CSHEDIT
		/*
		 * If had a history command :v modifier then
		 * go into edit mode. - afd
		 */
		if (editline) {
			editcmd(&paraml);
			editline = 0;
			paraml.next = paraml.prev = &paraml;
			paraml.word = "";
			err = 0;
			/*
			 * Echo new command line.
			 */
			if (lex(&paraml, 1) && !err && intty ||
			    adrof("verbose")) {
				haderr = 1;
				prlex(&paraml);
				haderr = 0;
			}
			
		}
#endif

		/*
		 * The parser may lose space if interrupted.
		 */
		if (setintr)
			(void) sigblock(sigmask(SIGINT));

		/*
		 * Save input text on the history list if 
		 * reading in old history, or it
		 * is from the terminal at the top level and not
		 * in a loop.
		 */
		if (enterhist || catch && intty && !whyles)
			savehist(&paraml);

		/*
		 * Print lexical error messages, except when sourcing
		 * history lists.
		 */
		if (!enterhist && err)
			/*
			 * It would be nice if we could bury eventno++ in
			 * error().  
			 * To many "uninteresting events" use error() to 
			 * jump back here.
			 */
			eventno++, error(err);

		/*
		 * If had a history command :p modifier then
		 * this is as far as we should go
		 */
		if (justpr)
			eventno++, reset();
		alias(&paraml);

		/*
		 * Parse the words of the input into a parse tree.
		 */
		t = syntax(paraml.next, &paraml, 0);
		if (err)
			eventno++, error(err);

		/*
		 * Increment the acutal event number here.
		 * If we waited till after execute(), interupted commands
		 * would not get their history counter incremented.
		 * We pad the eventno when savehist() above calls enthist() 
		 * to place the current command in the history list.
		 */
		if ( t && intty && !whyles ) 
			eventno++;
		/*
		 * Execute the parse tree
		 */
		execute(t, tpgrp);

		/*
		 * Made it!
		 */
		freelex(&paraml), freesyn(t);
	}
	resexit(osetexit);
}

dosource(t)
	register char **t;
{
	register char *f;
	register int u;
	bool hflg = 0;
	char buf[BUFSIZ];
	struct stat stb;

	t++;
	if (*t && eq(*t, "-h")) {
		t++;
		hflg++;
	}
	(void) strcpy(buf, *t);
	f = globone(buf);
	if(!hflg)					/* 004  RNF  */
	{
		if(stat(f, &stb) < 0)
			Perror(f);
		else
			if((stb.st_mode & S_IFMT) != S_IFREG)
			{
				seterr2(f, ": Not a regular file");
				error(err);
			}
	}
	u = dmove(open(f, 0), -1);
	xfree(f);
	if (u < 0 && !hflg)
		Perror(f);
	srcunit(u, 0, hflg);
}

/*
 * Check for mail.
 * If we are a login shell, then we don't want to tell
 * about any mail file unless its been modified
 * after the time we started.
 * This prevents us from telling the user things he already
 * knows, since the login program insists on saying
 * "You have mail."
 */
mailchk()
{
	register struct varent *v;
	register char **vp;
	time_t t;
	int intvl, cnt;
	struct stat stb;
	bool new;

	v = adrof("mail");
	if (v == 0)
		return;
	(void) time(&t);
	vp = v->vec;
	cnt = blklen(vp);
	intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
	if (intvl < 1)
		intvl = 1;
	if (chktim + intvl > t)
		return;
	for (; *vp; vp++) {
		if (stat(*vp, &stb) < 0)
			continue;
		new = stb.st_mtime > time0.tv_sec;
		if (stb.st_size == 0 || stb.st_atime > stb.st_mtime ||
		    (stb.st_atime < chktim && stb.st_mtime < chktim) ||
		    loginsh && !new)
			continue;
		if (cnt == 1)
			csh_printf("You have %smail.\n", new ? "new " : ""); /* 005 RNF */
		else
			csh_printf("%s in %s.\n", new ? "New mail" : "Mail", *vp);  /* 005 RNF */
	}
	chktim = t;
}

#include <pwd.h>
/*
 * Extract a home directory from the password file
 * The argument points to a buffer where the name of the
 * user whose home directory is sought is currently.
 * We write the home directory of the user back there.
 */
gethdir(home)
	char *home;
{
	register struct passwd *pp = getpwnam(home);

	if (pp == 0)
		return (1);
	(void) strcpy(home, pp->pw_dir);
	return (0);
}

/*
 * Move the initial descriptors to their eventual
 * resting places, closin all other units.
 */
initdesc()
{
	didfds = 0;			/* 0, 1, 2 aren't set up */
	SHIN = dcopy(0, FSHIN);
	SHOUT = dcopy(1, FSHOUT);
	SHDIAG = dcopy(2, FSHDIAG);
	OLDSTD = dcopy(SHIN, FOLDSTD);
	closem();
}

#ifdef PROF
done(i)
#else
exit(i)
#endif
	int i;
{

	untty();
	_exit(i);
}

printprompt ()
{
    register char *cp;
    register char **promptv;
    register struct varent *pvar;
    static int next_prompt = 0;
    register int pcount;

    if (!whyles) {
	/*
	 * Find end of prompts or next_prompt'th member
	 */

	pvar = adrof("prompt");
	if (pvar == 0 || (promptv = pvar->vec) == 0 || promptv[0] == 0) {
		cp = "";
	} else {
		pcount = 0;
		while (pcount <= next_prompt) {
			if (promptv[pcount] == 0) {
				next_prompt = 0;
				break;
			}
			pcount++;
		}
		cp = promptv[next_prompt];
		next_prompt++;
	}
	while (*cp) {
	    if (*cp == HIST) {
		csh_printf ("%d", eventno + 1);			/* 005 RNF */
	    } else {
		if (*cp == '\\' && cp[1] == HIST) {
		    cp++;
		}
		putchar (*cp | QUOTE);
	    }
	    cp++;
	}
    } else {
    /* 
     * Prompt for forward reading loop
     * body content.
     */
	csh_printf ("? ");					/* 005 RNF */
    }
    flush ();
}