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more boilerplate before work really begins

--- /dev/null

+++ b/9curses.h

@@ -1,0 +1,57 @@

+/* This header is cursed.

+ *

+ * The functions and whatnot here are aimed at providing a layer of compatibility

+ * between ncurses-like interfaces and cursedfs to avoid too much rewriting.

+ */

+ 

+//  stub

+#define KEY_UP L'↑'

+//  stub

+#define KEY_DOWN L'↓'

+// Stub

+#define stdscr 0

+

+typedef struct WINDOW WINDOW;

+

+// Clear the screen

+void clear();

+

+// Initialize a new WINDOW

+WINDOW* newwin(uint, uint, uint, uint);

+

+// Clean up and close a WINDOW

+endwin();

+

+// Analogue to print for a string from origin y,x

+int mvprintw(int y, int x, char *fmt, ...);

+

+// Sets a character at y,x

+mvaddch(int y, int x, char c);

+

+// Get a 'raw' character input from the user

+getch();

+

+// Initialize the screen

+initscr();

+

+// Set raw mode for the screen

+raw();

+

+// Don't echo keypress characters to the screen

+noecho();

+

+// Place the cursor at location y,x

+curs_set();

+

+// Set delay until escape sequence potential is ignored

+set_escdelay();

+

+// Refresh the screen

+refresh();

+

+// Refresh a window

+wrefresh(WINDOW*);

+

+struct WINDOW{

+	s8int naught;// Stub

+};

--- /dev/null

+++ b/cursed.c

@@ -1,0 +1,72 @@

+#include <u.h>

+#include <libc.h>

+#include <fcall.h>

+#include <thread.h>

+#include <9p.h>

+#include "cursed.h"

+

+Sem *sems[Nsems];

+

+Sem *

+newsem(char *name)

+{

+	int i;

+

+	for(i = 0; i < Nsems; i++)

+		if(sems[i] == nil)

+			break;

+	if(i == Nsems)

+		return nil;

+	sems[i] = emalloc9p(sizeof(Sem));

+	memset(sems[i], 0, sizeof(Sem));

+	sems[i]->ref = 2;

+	sems[i]->name = estrdup9p(name);

+	return sems[i];

+}

+

+void

+closesem(Sem *s)

+{

+	if(s != nil && decref(s) == 0){

+		assert(s->reqs == nil);

+		assert(sems[s->id] == s);

+		sems[s->id] = nil;

+		free(s->name);

+		free(s);

+	}

+}

+

+void

+queuereq(Sem *s, Req *r)

+{

+	QReq *q;

+	QReq **l;

+

+	q = emalloc9p(sizeof(QReq));

+	q->r = r;

+	q->next = nil;

+	for(l = &s->reqs; *l != nil; l = &(*l)->next)

+		;

+	*l = q;

+}

+

+Req *

+dequeuereq(Sem *s)

+{

+	QReq *q;

+	Req *r;

+

+	if(s->reqs == nil)

+		return nil;

+	q = s->reqs;

+	s->reqs = q->next;

+	r = q->r;

+	free(q);

+	return r;

+}

+

+int

+queuedreqs(Sem *s)

+{

+	return s->reqs != nil;

+}

--- /dev/null

+++ b/cursed.h

@@ -1,0 +1,24 @@

+typedef struct Sem Sem;

+typedef struct QReq QReq;

+

+struct Sem{

+	Ref;

+	int		id;		// index in array; qid.path

+	char		*name;	// of file

+	int		tickets;

+	QReq	*reqs;	// reads (i.e., downs) pending

+};

+

+struct QReq{

+	QReq	*next;	// in pending request list

+	Req		*r;		// the request pending

+};

+

+#define Nsems 32

+extern Sem *sems[];

+

+extern Sem *newsem(char *name);

+extern void closesem(Sem *s);

+extern void queuereq(Sem *s, Req *r);

+extern Req *dequeuereq(Sem *s);

+extern int queuedreqs(Sem *s);

--- /dev/null

+++ b/cursedfs.c

@@ -1,0 +1,250 @@

+#include <u.h>

+#include <libc.h>

+#include <auth.h>

+#include <fcall.h>

+#include <thread.h>

+#include <9p.h>

+#include "cursed.h"

+

+static void

+fsattach(Req *r)

+{

+	r->fid->qid = (Qid) { 0, 0, QTDIR };

+	r->ofcall.qid = r->fid->qid;

+	respond(r, nil);

+}

+

+static void

+fscreate(Req *r)

+{

+	Fid *fid;

+	Qid q;

+	Sem *s;

+

+	fid = r->fid;

+	q = fid->qid;

+	if(!(q.type & QTDIR)){

+		respond(r, "not a directory");

+		return;

+	}

+	s = newsem(r->ifcall.name);

+	fid->qid = (Qid){s->id, 0, 0};

+	fid->aux = s;

+	fid->omode = r->ifcall.mode;

+	incref(s);

+	r->ofcall.qid = fid->qid;

+	respond(r, nil);

+}

+

+static void

+fsremove(Req *r)

+{

+	Req *q;

+	Sem *s;

+

+	s = r->fid->aux;

+	while(q = dequeuereq(s))

+		respond(q, "file has bee removed");

+	closesem(s);

+	r->fid->aux = nil;

+	closesem(s);	// release reference from sems[]

+	respond(r, nil);

+}

+

+static int

+getdirent(int n, Dir *d, void *)

+{

+	d->atime = time(nil);

+	d->mtime = d->atime;

+	d->uid = estrdup9p(getuser());

+	d->gid = estrdup9p(d->uid);

+	d->muid = estrdup9p(d->uid);

+	if(n == -1){

+		d->qid = (Qid) {0, 0, QTDIR};

+		d->mode = 0775;

+		d->name = estrdup9p("/");

+		d->length = 0;

+	}else if(n >= 0 && n < Nsems && sems[n] != nil){

+		d->qid = (Qid) {n, 0, 0};

+		d->mode = 0664;

+		d->name = estrdup9p(sems[n]->name);

+		d->length = sems[n]->tickets;

+	}else

+		return -1;

+	return 0;

+}

+

+static void

+fsread(Req *r)

+{

+	Fid *fid;

+	Qid q;

+	Sem	*s;

+	char	nl[] = "\n";

+

+	fid = r->fid;

+	q = fid->qid;

+	if(q.type & QTDIR){

+		dirread9p(r, getdirent, nil);

+		respond(r, nil);

+		return;

+	}

+	s = fid->aux;

+	if(s->tickets > 0){

+		s->tickets--;

+		readstr(r, nl);

+		respond(r, nil);

+	}else

+		queuereq(s, r);

+}

+

+static void

+fswrite(Req *r)

+{

+	Fid *fid;

+	Qid q;

+	Sem	*s;

+	Req *qr;

+	char	str[10];

+	char	nl[] = "\n";

+

+	fid = r->fid;

+	q = fid->qid;

+	if(q.type & QTDIR){

+		respond(r, "permission denied");

+		return;

+	}

+	if(r->ifcall.count > sizeof(str) - 1){

+		respond(r, "string too large");

+		return;

+	}

+	memmove(str, r->ifcall.data, r->ifcall.count);

+	str[r->ifcall.count] = 0;

+	s = fid->aux;

+	s->tickets += atoi(str);

+

+	while(s->tickets > 0 && queuedreqs(s)){

+		qr = dequeuereq(s);

+		qr->ofcall.count = 1;

+		s->tickets--;

+		readstr(qr, nl);

+		respond(qr, nil);

+	}

+	respond(r, nil);

+}

+

+static char *

+fswalkl(Fid * fid, char *name, Qid *qid)

+{

+	Qid q;

+	Sem	*s;

+	int i;

+

+	q = fid->qid;

+	s = fid->aux;

+	if(!(q.type && QTDIR)){

+		if(!strcmp(name, "..")){

+			fid->qid = (Qid) {0, 0, QTDIR};

+			*qid = fid->qid;

+			closesem(s);

+			fid->aux = nil;

+			return nil;

+		}

+	}else{

+		for(i = 0; i < Nsems; i++)

+			if(sems[i] && !strcmp(name, sems[i]->name)){

+				fid->qid = (Qid){i, 0, 0};

+				incref(sems[i]);

+				closesem(fid->aux);

+				fid->aux = sems[i];

+				*qid = fid->qid;

+				return nil;

+			}

+	}

+	return "no such file";

+}

+

+static char *

+fsclone(Fid *fid, Fid *newfid)

+{

+	Sem *s;

+

+	s  = fid->aux;

+	if(s != nil)

+		incref(s);

+	newfid->aux = s;

+	return nil;

+}

+

+static void

+fsstat(Req *r)

+{

+	Fid *fid;

+	Qid q;

+

+	fid = r->fid;

+	q = fid->qid;

+	if(q.type & QTDIR)

+		getdirent(-1, &r->d, nil);

+	else

+		getdirent(q.path, &r->d, nil);

+	respond(r, nil);

+}

+

+static void

+freefid(Fid *fid)

+{

+	Sem *s;

+

+	s = fid->aux;

+	fid->aux = nil;

+	closesem(s);

+}

+

+static Srv sfs = 

+{

+	.attach	=	fsattach,

+	.create	=	fscreate,

+	.remove	=	fsremove,

+	.read		=	fsread,

+	.write	=	fswrite,

+	.walk1	=	fswalkl,

+	.clone	=	fsclone,

+	.stat		=	fsstat,

+	.destroyfid =	freefid,

+};

+

+

+void

+usage(void)

+{

+	fprint(2, "usage: %s [-D] [-s srv] [-m mnt]\n", argv0);

+	threadexitsall("usage");

+}

+

+void

+threadmain(int argc, char *argv[])

+{

+	char	*mnt, *srv;

+

+	srv = nil;

+	mnt = "/mnt/sem";

+	ARGBEGIN{

+	case 'D':

+		chatty9p++;

+		break;

+	case 's':

+		srv = EARGF(usage());

+		break;

+	case 'm':

+		mnt = EARGF(usage());

+		break;

+	default:

+		usage();

+	}ARGEND;

+

+	if(argc != 0)

+		usage();

+	threadpostmountsrv(&sfs, srv, mnt, MREPL|MCREATE);

+	threadexits(nil);

+}

--- /dev/null

+++ b/mkfile

@@ -1,0 +1,15 @@

+</$objtype/mkfile

+

+TARG = cursedfs

+

+OFILES = \

+	cursed.$O \

+	cursedfs.$O

+

+HFILES = \

+	cursed.h \

+	9curses.h

+

+BIN = $home/bin/$objtype

+

+</sys/src/cmd/mkone