skel(3) → skelfs(4)

The original intention was to put devskel in to the
kernel to detach what it provides from devsrv.
That is not a good reason, just move it to userspace.

auth/box has been changed to exec skelfs instead
of relying on '#z'.

1 files changed, 251 insertions, 0 deletions

diff --git a/sys/src/cmd/skelfs.c b/sys/src/cmd/skelfs.c
new file mode 100644
index 000000000..137e19397
--- /dev/null
+++ b/sys/src/cmd/skelfs.c
@@ -0,0 +1,251 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+
+typedef struct Skel Skel;
+struct Skel {
+	char name[64];
+	char mode;
+};
+
+static uvlong 	sessions;
+static char	defmode;
+
+enum{
+	Qroot,
+	Qdir,
+	Qskel,
+};
+
+#define qtype(x)	(((ulong)x)&0x1f)
+#define qsess(x)	((((ulong)x))>>5)
+#define mkqid(i,t)	((((ulong)i)<<5)|(t))
+
+static int
+step(Fid *f, int way, Qid *res, Dir *dp)
+{
+	Skel *s;
+	int path;
+	char *name;
+	ulong perm;
+
+	s = f->aux;
+	name = s->name;
+	perm = 0550|DMDIR;
+	path = qtype(f->qid.path) + way;
+	if(!name[0] && way > 0)
+		return -1;
+
+	if(path < 0)
+		goto Root;
+	switch(path){
+	Root:
+	case Qroot:
+		name = "/";
+		/* fallthrough */
+	case Qdir:
+		res->type = QTDIR;
+		break;
+	case Qskel:
+		switch(s->mode){
+		case 'd':
+			res->type = QTDIR;
+			break;
+		case 'f':
+		default:
+			res->type = QTFILE;
+			perm = 0;
+			break;
+		}
+		break;
+	default:
+		return -1;
+	}
+	res->vers = qsess(f->qid.path);
+	res->path = mkqid(res->vers, path);
+	if(dp){
+		dp->mode = perm;
+		dp->name = estrdup9p(name);
+		dp->uid = estrdup9p("sys");
+		dp->gid = estrdup9p("sys");
+		dp->qid = *res;
+		dp->length = 0;
+	}
+	return 1;
+}
+
+static int
+dirgen(int i, Dir *d, void *a)
+{
+	Fid *f;
+	Qid q;
+
+	if(i > 0)
+		return -1;
+	f = a;
+	return step(f, 1, &q, d);
+}
+
+static void
+fidclunk(Fid *fid)
+{
+	free(fid->aux);
+}
+
+static char*
+fsclone(Fid *old, Fid *new, void*)
+{
+	Skel *s, *s2;
+
+	s = old->aux;
+	s2 = emalloc9p(sizeof *s2);
+	if(s2 == nil)
+		return "out of memory";
+	memset(s2, 0, sizeof *s2);
+
+	s2->mode = s->mode;
+	utfecpy(s2->name, &s2->name[sizeof s2->name-1], s->name);
+	new->aux = s2;
+	return nil;
+}
+
+static char*
+fswalk1(Fid *old, char *name, void*)
+{
+	Skel *s;
+
+	if(strcmp("..", name) == 0){
+		step(old, -1, &old->qid, nil);
+		return nil;
+	}
+
+	s = old->aux;
+	if(!s->name[0] && qtype(old->qid.path) == Qroot && s->mode != 'e'){
+		utfecpy(s->name, &s->name[sizeof s->name-1], name);
+		old->qid.vers = sessions++;
+		old->qid.path = mkqid(old->qid.vers, qtype(old->qid.path));
+	} else if(strcmp(name, s->name) != 0)
+		return "does not exist";
+
+	if(step(old, 1, &old->qid, nil) < 0)
+		return "does not exist";
+
+	return nil;
+}
+
+static void
+fswalk(Req *r)
+{
+	walkandclone(r, fswalk1, fsclone, nil);
+}
+
+static void
+fsattach(Req *r)
+{
+	Skel s;
+	Fid root;
+	char *spec;
+	Qid *q;
+
+	spec = r->ifcall.aname;
+	if(spec && spec[0] != '\0')
+		s.mode = spec[0];
+	else
+		s.mode = defmode;
+
+	q = &r->fid->qid;
+	q->vers = sessions++;
+	q->path = mkqid(q->vers, Qroot);
+	q->type = QTDIR;
+	r->ofcall.qid = *q;
+
+	s.name[0] = '\0';
+	root.aux = &s;
+	respond(r, fsclone(&root, r->fid, nil));
+}
+
+static void
+fsstat(Req *r)
+{
+	Qid q;
+
+	if(step(r->fid, 0, &q, &r->d) < 0)
+		respond(r, "does not exist");
+	respond(r, nil);
+}
+
+static void
+fsread(Req *r)
+{
+	dirread9p(r, dirgen, r->fid);
+	respond(r, nil);
+}
+
+static void
+fsopen(Req *r)
+{
+	r->ofcall.mode = r->ifcall.mode;
+	if(r->ifcall.mode != OREAD)
+		respond(r, "permission denied");
+	else
+		respond(r, nil);
+}
+
+Srv fs=
+{
+.attach=	fsattach,
+.open=		fsopen,
+.read=		fsread,
+.stat=		fsstat,
+.walk=		fswalk,
+.destroyfid=	fidclunk
+};
+
+void
+usage(void)
+{
+	fprint(2, "usage: %s [ -Di ] [ -s service ] [ -t mode ] [ mntpt ]\n", argv0);
+	exits("usage");
+}
+
+void
+main(int argc, char **argv)
+{
+	char *s, *mode;
+	int stdio;
+
+	s = nil;
+	stdio = 0;
+	defmode = 'f';
+	ARGBEGIN{
+	case 'D':
+		chatty9p++;
+		break;
+	case 's':
+		s = EARGF(usage());
+		break;
+	case 'i':
+		stdio = 1;
+		break;
+	case 't':
+		mode = EARGF(usage());
+		defmode = mode[0];
+		break;
+	default:
+		usage();
+	}ARGEND
+
+	if(argc > 1)
+		usage();
+
+	if(stdio == 0){
+		postmountsrv(&fs, s, argc ? argv[0] : "/mnt/skel", MREPL);
+		exits(nil);
+	}
+	fs.infd = 0;
+	fs.outfd = 1;
+	srv(&fs);
+	exits(nil);
+}