exec.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

			bufread(t->file, q0, r, n);
			bufinsert(&snarfbuf, snarfbuf.nc, r, n);
			q0 += n;
		}
		fbuffree(r);
		putsnarf();
	}
	if(docut){
		textdelete(t, t->q0, t->q1, TRUE);
		textsetselect(t, t->q0, t->q0);
		if(t->w){
			textscrdraw(t);
			winsettag(t->w);
		}
	}else if(dosnarf)	/* Snarf command */
		argtext = t;
	if(locked)
		winunlock(t->w);
}

void
paste(Text *et, Text *t, Text*, int selectall, int tobody, Rune*, int)
{
	int c;
	uint q, q0, q1, n;
	Rune *r;

	/* if(tobody), use body of executing window  (Paste or Send command) */
	if(tobody && et!=nil && et->w!=nil){
		t = &et->w->body;
		filemark(t->file);	/* seq has been incremented by execute */
	}
	if(t == nil)
		return;

	getsnarf();
	if(t==nil || snarfbuf.nc==0)
		return;
	if(t->w!=nil && et->w!=t->w){
		c = 'M';
		if(et->w)
			c = et->w->owner;
		winlock(t->w, c);
	}
	cut(t, t, nil, FALSE, TRUE, nil, 0);
	q = 0;
	q0 = t->q0;
	q1 = t->q0+snarfbuf.nc;
	r = fbufalloc();
	while(q0 < q1){
		n = q1 - q0;
		if(n > RBUFSIZE)
			n = RBUFSIZE;
		if(r == nil)
			r = runemalloc(n);
		bufread(&snarfbuf, q, r, n);
		textinsert(t, q0, r, n, TRUE);
		q += n;
		q0 += n;
	}
	fbuffree(r);
	if(selectall)
		textsetselect(t, t->q0, q1);
	else
		textsetselect(t, q1, q1);
	if(t->w){
		textscrdraw(t);
		winsettag(t->w);
	}
	if(t->w!=nil && et->w!=t->w)
		winunlock(t->w);
}

void
look(Text *et, Text *t, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *r;
	int n;

	if(et && et->w){
		t = &et->w->body;
		if(narg > 0){
			search(t, arg, narg);
			return;
		}
		getarg(argt, FALSE, FALSE, &r, &n);
		if(r == nil){
			n = t->q1-t->q0;
			r = runemalloc(n);
			bufread(t->file, t->q0, r, n);
		}
		search(t, r, n);
		free(r);
	}
}

void
sendx(Text *et, Text *t, Text*, int, int, Rune*, int)
{
	if(et->w==nil)
		return;
	t = &et->w->body;
	if(t->q0 != t->q1)
		cut(t, t, nil, TRUE, FALSE, nil, 0);
	textsetselect(t, t->file->nc, t->file->nc);
	paste(t, t, nil, TRUE, TRUE, nil, 0);
	if(textreadc(t, t->file->nc-1) != '\n'){
		textinsert(t, t->file->nc, L"\n", 1, TRUE);
		textsetselect(t, t->file->nc, t->file->nc);
	}
}

void
edit(Text *et, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *r;
	int len;

	if(et == nil)
		return;
	getarg(argt, FALSE, TRUE, &r, &len);
	seq++;
	if(r != nil){
		editcmd(et, r, len);
		free(r);
	}else
		editcmd(et, arg, narg);
}

void
exit(Text*, Text*, Text*, int, int, Rune*, int)
{
	if(rowclean(&row)){
		sendul(cexit, 0);
		threadexits(nil);
	}
}

void
putall(Text*, Text*, Text*, int, int, Rune*, int)
{
	int i, j, e;
	Window *w;
	Column *c;
	char *a;

	for(i=0; i<row.ncol; i++){
		c = row.col[i];
		for(j=0; j<c->nw; j++){
			w = c->w[j];
			if(w->isscratch || w->isdir || w->body.file->nname==0)
				continue;
			if(w->nopen[QWevent] > 0)
				continue;
			a = runetobyte(w->body.file->name, w->body.file->nname);
			e = access(a, 0);
			if(w->body.file->mod || w->body.ncache)
				if(e < 0)
					warning(nil, "no auto-Put of %s: %r\n", a);
				else{
					wincommit(w, &w->body);
					put(&w->body, nil, nil, XXX, XXX, nil, 0);
				}
			free(a);
		}
	}
}


void
id(Text *et, Text*, Text*, int, int, Rune*, int)
{
	if(et && et->w)
		warning(nil, "/mnt/acme/%d/\n", et->w->id);
}

void
local(Text *et, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	char *a, *aa;
	Runestr dir;

	aa = getbytearg(argt, TRUE, TRUE, &a);

	dir = dirname(et, nil, 0);
	if(dir.nr==1 && dir.r[0]=='.'){	/* sigh */
		free(dir.r);
		dir.r = nil;
		dir.nr = 0;
	}
	run(nil, runetobyte(arg, narg), dir.r, dir.nr, FALSE, aa, a, FALSE);
}

void
kill(Text*, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *a, *cmd, *r;
	int na;

	getarg(argt, FALSE, FALSE, &r, &na);
	if(r)
		kill(nil, nil, nil, 0, 0, r, na);
	/* loop condition: *arg is not a blank */
	for(;;){
		a = findbl(arg, narg, &na);
		if(a == arg)
			break;
		cmd = runemalloc(narg-na+1);
		runemove(cmd, arg, narg-na);
		sendp(ckill, cmd);
		arg = skipbl(a, na, &narg);
	}
}

void
fontx(Text *et, Text *t, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *a, *r, *flag, *file;
	int na, nf;
	char *aa;
	Reffont *newfont;
	Dirlist *dp;
	int i, fix;

	if(et==nil || et->w==nil)
		return;
	t = &et->w->body;
	flag = nil;
	file = nil;
	/* loop condition: *arg is not a blank */
	nf = 0;
	for(;;){
		a = findbl(arg, narg, &na);
		if(a == arg)
			break;
		r = runemalloc(narg-na+1);
		runemove(r, arg, narg-na);
		if(runeeq(r, narg-na, L"fix", 3) || runeeq(r, narg-na, L"var", 3)){
			free(flag);
			flag = r;
		}else{
			free(file);
			file = r;
			nf = narg-na;
		}
		arg = skipbl(a, na, &narg);
	}
	getarg(argt, FALSE, TRUE, &r, &na);
	if(r)
		if(runeeq(r, na, L"fix", 3) || runeeq(r, na, L"var", 3)){
			free(flag);
			flag = r;
		}else{
			free(file);
			file = r;
			nf = na;
		}
	fix = 1;
	if(flag)
		fix = runeeq(flag, runestrlen(flag), L"fix", 3);
	else if(file == nil){
		newfont = rfget(FALSE, FALSE, FALSE, nil);
		if(newfont)
			fix = strcmp(newfont->f->name, t->font->name)==0;
	}
	if(file){
		aa = runetobyte(file, nf);
		newfont = rfget(fix, flag!=nil, FALSE, aa);
		free(aa);
	}else
		newfont = rfget(fix, FALSE, FALSE, nil);
	if(newfont){
		draw(screen, t->w->r, textcols[BACK], nil, ZP);
		rfclose(t->reffont);
		t->reffont = newfont;
		t->font = newfont->f;
		frinittick(t);
		if(t->w->isdir){
			t->all.min.x++;	/* force recolumnation; disgusting! */
			for(i=0; i<t->w->ndl; i++){
				dp = t->w->dlp[i];
				aa = runetobyte(dp->r, dp->nr);
				dp->wid = stringwidth(newfont->f, aa);
				free(aa);
			}
		}
		/* avoid shrinking of window due to quantization */
		colgrow(t->w->col, t->w, -1);
	}
	free(file);
	free(flag);
}

void
incl(Text *et, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *a, *r;
	Window *w;
	int na, n, len;

	if(et==nil || et->w==nil)
		return;
	w = et->w;
	n = 0;
	getarg(argt, FALSE, TRUE, &r, &len);
	if(r){
		n++;
		winaddincl(w, r, len);
	}
	/* loop condition: *arg is not a blank */
	for(;;){
		a = findbl(arg, narg, &na);
		if(a == arg)
			break;
		r = runemalloc(narg-na+1);
		runemove(r, arg, narg-na);
		n++;
		winaddincl(w, r, narg-na);
		arg = skipbl(a, na, &narg);
	}
	if(n==0 && w->nincl){
		for(n=w->nincl; --n>=0; )
			warning(nil, "%S ", w->incl[n]);
		warning(nil, "\n");
	}
}

enum {
	IGlobal = -2,
	IError = -1,
	Ion = 0,
	Ioff = 1,
};

static int
indentval(Rune *s, int n)
{
	if(n < 2)
		return IError;
	if(runestrncmp(s, L"ON", n) == 0){
		globalautoindent = TRUE;
		warning(nil, "Indent ON\n");
		return IGlobal;
	}
	if(runestrncmp(s, L"OFF", n) == 0){
		globalautoindent = FALSE;
		warning(nil, "Indent OFF\n");
		return IGlobal;
	}
	return runestrncmp(s, L"on", n) == 0;
}

void
indent(Text *et, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *a, *r;
	Window *w;
	int na, len, autoindent;

	w = nil;
	if(et!=nil && et->w!=nil)
		w = et->w;
	autoindent = IError;
	getarg(argt, FALSE, TRUE, &r, &len);
	if(r!=nil && len>0)
		autoindent = indentval(r, len);
	else{
		a = findbl(arg, narg, &na);
		if(a != arg)
			autoindent = indentval(arg, narg-na);
	}
	if(w != nil){
		switch(autoindent){
		case Ion:
		case Ioff:
			w->autoindent = autoindent;
			break;
		case IGlobal:
			w->autoindent = globalautoindent;
			break;
		}
	}
}

void
tab(Text *et, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	Rune *a, *r;
	Window *w;
	int na, len, tab;
	char *p;

	if(et==nil || et->w==nil)
		return;
	w = et->w;
	getarg(argt, FALSE, TRUE, &r, &len);
	tab = 0;
	if(r!=nil && len>0){
		p = runetobyte(r, len);
		if('0'<=p[0] && p[0]<='9')
			tab = atoi(p);
		free(p);
	}else{
		a = findbl(arg, narg, &na);
		if(a != arg){
			p = runetobyte(arg, narg-na);
			if('0'<=p[0] && p[0]<='9')
				tab = atoi(p);
			free(p);
		}
	}
	if(tab > 0){
		if(w->body.tabstop != tab){
			w->body.tabstop = tab;
			winresize(w, w->r, 1);
		}
	}else
		warning(nil, "%.*S: Tab %d\n", w->body.file->nname, w->body.file->name, w->body.tabstop);
}

void
runproc(void *argvp)
{
	/* args: */
		Window *win;
		char *s;
		Rune *rdir;
		int ndir;
		int newns;
		char *argaddr;
		char *arg;
		Command *c;
		Channel *cpid;
		int iseditcmd;
	/* end of args */
	char *e, *t, *name, *filename, *dir, **av, *news;
	Rune r, **incl;
	int ac, w, inarg, i, n, fd, nincl, winid;
	int pipechar;
	char buf[512];
	static void *parg[2];
	void **argv;

	argv = argvp;
	win = argv[0];
	s = argv[1];
	rdir = argv[2];
	ndir = (uintptr)argv[3];
	newns = (uintptr)argv[4];
	argaddr = argv[5];
	arg = argv[6];
	c = argv[7];
	cpid = argv[8];
	iseditcmd = (uintptr)argv[9];
	free(argv);

	t = s;
	while(*t==' ' || *t=='\n' || *t=='\t')
		t++;
	for(e=t; *e; e++)
		if(*e==' ' || *e=='\n' || *e=='\t' )
			break;
	name = emalloc((e-t)+2);
	memmove(name, t, e-t);
	name[e-t] = 0;
	e = utfrrune(name, '/');
	if(e)
		memmove(name, e+1, strlen(e+1)+1);	/* strcpy but overlaps */
	strcat(name, " ");	/* add blank here for ease in waittask */
	c->name = bytetorune(name, &c->nname);
	free(name);
	pipechar = 0;
	if(*t=='<' || *t=='|' || *t=='>')
		pipechar = *t++;
	c->iseditcmd = iseditcmd;
	c->text = s;
	if(rdir != nil){
		dir = runetobyte(rdir, ndir);
		chdir(dir);	/* ignore error: probably app. window */
		free(dir);
	}
	if(newns){
		nincl = 0;
		incl = nil;
		if(win){
			filename = smprint("%.*S", win->body.file->nname, win->body.file->name);
			nincl = win->nincl;
			if(nincl > 0){
				incl = emalloc(nincl*sizeof(Rune*));
				for(i=0; i<nincl; i++){
					n = runestrlen(win->incl[i]);
					incl[i] = runemalloc(n+1);
					runemove(incl[i], win->incl[i], n);
				}
			}
			winid = win->id;
		}else{
			filename = nil;
			winid = 0;
			if(activewin)
				winid = activewin->id;
		}
		rfork(RFNAMEG|RFENVG|RFFDG|RFNOTEG);
		sprint(buf, "%d", winid);
		putenv("winid", buf);

		if(filename){
			putenv("%", filename);
			free(filename);
		}
		c->md = fsysmount(rdir, ndir, incl, nincl);
		if(c->md == nil){
			fprint(2, "child: can't mount /dev/cons: %r\n");
			threadexits("mount");
		}
		close(0);
		if(winid>0 && (pipechar=='|' || pipechar=='>')){
			sprint(buf, "/mnt/acme/%d/rdsel", winid);
			open(buf, OREAD);
		}else
			open("/dev/null", OREAD);
		close(1);
		if((winid>0 || iseditcmd) && (pipechar=='|' || pipechar=='<')){
			if(iseditcmd){
				if(winid > 0)
					sprint(buf, "/mnt/acme/%d/editout", winid);
				else
					sprint(buf, "/mnt/acme/editout");
			}else
				sprint(buf, "/mnt/acme/%d/wrsel", winid);
			open(buf, OWRITE);
			close(2);
			open("/dev/cons", OWRITE);
		}else{
			open("/dev/cons", OWRITE);
			dup(1, 2);
		}
	}else{
		rfork(RFFDG|RFNOTEG);
		fsysclose();
		close(0);
		open("/dev/null", OREAD);
		close(1);
		open(acmeerrorfile, OWRITE);
		dup(1, 2);
	}

	if(win)
		winclose(win);

	if(argaddr)
		putenv("acmeaddr", argaddr);
	if(strlen(t) > sizeof buf-10)	/* may need to print into stack */
		goto Hard;
	inarg = FALSE;
	for(e=t; *e; e+=w){
		w = chartorune(&r, e);
		if(r==' ' || r=='\t')
			continue;
		if(r < ' ')
			goto Hard;
		if(utfrune("#;&|^$=`'{}()<>[]*?^~`", r))
			goto Hard;
		inarg = TRUE;
	}
	if(!inarg)
		goto Fail;

	ac = 0;
	av = nil;
	inarg = FALSE;
	for(e=t; *e; e+=w){
		w = chartorune(&r, e);
		if(r==' ' || r=='\t'){
			inarg = FALSE;
			*e = 0;
			continue;
		}
		if(!inarg){
			inarg = TRUE;
			av = realloc(av, (ac+1)*sizeof(char**));
			av[ac++] = e;
		}
	}
	av = realloc(av, (ac+2)*sizeof(char**));
	av[ac++] = arg;
	av[ac] = nil;
	c->av = av;
	procexec(cpid, av[0], av);
	e = av[0];
	if(e[0]=='/' || (e[0]=='.' && e[1]=='/'))
		goto Fail;
	if(cputype){
		sprint(buf, "%s/%s", cputype, av[0]);
		procexec(cpid, buf, av);
	}
	sprint(buf, "/bin/%s", av[0]);
	procexec(cpid, buf, av);
	goto Fail;

Hard:

	/*
	 * ugly: set path = (. $cputype /bin)
	 * should honor $path if unusual.
	 */
	if(cputype){
		n = 0;
		memmove(buf+n, ".", 2);
		n += 2;
		i = strlen(cputype)+1;
		memmove(buf+n, cputype, i);
		n += i;
		memmove(buf+n, "/bin", 5);
		n += 5;
		fd = create("/env/path", OWRITE, 0666);
		write(fd, buf, n);
		close(fd);
	}

	if(arg){
		news = emalloc(strlen(t) + 1 + 1 + strlen(arg) + 1 + 1);
		if(news){
			sprint(news, "%s '%s'", t, arg);	/* BUG: what if quote in arg? */
			free(s);
			t = news;
			c->text = news;
		}
	}
	procexecl(cpid, "/bin/rc", "rc", "-c", t, nil);

   Fail:
	/* procexec hasn't happened, so send a zero */
	sendul(cpid, 0);
	threadexits(nil);
}

void
runwaittask(void *v)
{
	Command *c;
	Channel *cpid;
	void **a;

	threadsetname("runwaittask");
	a = v;
	c = a[0];
	cpid = a[1];
	free(a);
	do
		c->pid = recvul(cpid);
	while(c->pid == ~0);
	free(c->av);
	if(c->pid != 0)	/* successful exec */
		sendp(ccommand, c);
	else{
		if(c->iseditcmd)
			sendul(cedit, 0);
		free(c->name);
		free(c->text);
		free(c);
	}
	chanfree(cpid);
}

void
run(Window *win, char *s, Rune *rdir, int ndir, int newns, char *argaddr, char *xarg, int iseditcmd)
{
	void **arg;
	Command *c;
	Channel *cpid;

	if(s == nil)
		return;

	arg = emalloc(10*sizeof(void*));
	c = emalloc(sizeof *c);
	cpid = chancreate(sizeof(ulong), 0);
	arg[0] = win;
	arg[1] = s;
	arg[2] = rdir;
	arg[3] = (void*)ndir;
	arg[4] = (void*)newns;
	arg[5] = argaddr;
	arg[6] = xarg;
	arg[7] = c;
	arg[8] = cpid;
	arg[9] = (void*)iseditcmd;
	proccreate(runproc, arg, STACK);
	/* mustn't block here because must be ready to answer mount() call in run() */
	arg = emalloc(2*sizeof(void*));
	arg[0] = c;
	arg[1] = cpid;
	threadcreate(runwaittask, arg, STACK);
}