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ream: add special "adm" snapshot for users file

Until now, we loaded users from /adm/users in the
main snapshot; this made main more special than
necessary, and made it ambiguous which snapshot
users would get permissions from when traveling
through time.

Now, the adm label makes it unambiguous.

--- a/load.c

+++ b/load.c

@@ -105,8 +105,9 @@

 	fprint(2, "\tnextgen:\t%lld\n", fs->nextgen);

 	fprint(2, "\tblocksize:\t%lld\n", Blksz);

 	fprint(2, "\tcachesz:\t%lld MiB\n", fs->cmax*Blksz/MiB);

-	if((t = opensnap("main")) == nil)

+	if((t = opensnap("adm")) == nil)

 		sysfatal("load users: no main label");

 	if((e = loadusers(2, t)) != nil)

 		sysfatal("load users: %s\n", e);

+	closesnap(t);

 }

--- a/ream.c

+++ b/ream.c

@@ -6,8 +6,80 @@

 #include "dat.h"

 #include "fns.h"

+enum {

+	Qmainroot,

+	Qadmroot,

+	Qadmuser,

+	Nreamqid,

+};

+char *defaultusers =

+	"-1:adm::glenda\n"

+	"0:none::\n"

+	"1:tor:tor:\n"

+	"2:glenda:glenda:\n"

+	"10000:sys::\n"

+	"10001:map:map:\n"

+	"10002:doc::\n"

+	"10003:upas:upas:\n"

+	"10004:font::\n"

+	"10005:bootes:bootes:\n";

+

 static void

+fillxdir(Xdir *d, vlong qid, char *name, int type, int mode)

+{

+	memset(d, 0, sizeof(Xdir));

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

+	d->mode = mode;

+	d->atime = 0;

+	d->mtime = 0;

+	d->length = 0;

+	d->name = name;

+	d->uid = -1;

+	d->gid = -1;

+	d->muid = 0;

+}

+

+static void

+initadm(Blk *r, Blk *u)

+{

+	char *p, kbuf[Keymax], vbuf[Inlmax];

+	Kvp kv;

+	Xdir d;

+

+	/* nb: values must be inserted in key order */

+	kv.k = kbuf;

+	kv.nk = Offksz;

+	kv.v = vbuf;

+	kv.nv = Ptrsz;

+	kbuf[0] = Kdat;

+	PACK64(kbuf+1, (uvlong)Qadmuser);

+	PACK64(kbuf+9, 0ULL);

+	packbp(kv.v, kv.nv, &u->bp);

+	setval(r, &kv);

+

+	fillxdir(&d, Qadmuser, "users", QTFILE, 0664);

+	d.length = strlen(defaultusers);

+	if(dir2kv(Qadmroot, &d, &kv, vbuf, sizeof(vbuf)) == -1)

+		sysfatal("ream: pack users: %r");

+	setval(r, &kv);

+	fillxdir(&d, Qadmroot, "", QTDIR, DMDIR|0775);

+	if(dir2kv(-1, &d, &kv, vbuf, sizeof(vbuf)) == -1)

+		sysfatal("ream: pack root: %r");

+	setval(r, &kv);

+

+	if((p = packsuper(kbuf, sizeof(kbuf), 0)) == nil)

+		sysfatal("ream: pack super");

+	kv.k = kbuf;

+	kv.nk = p - kbuf;

+	if((p = packdkey(vbuf, sizeof(vbuf), -1, "")) == nil)

+		sysfatal("ream: pack super");

+	kv.v = vbuf;

+	kv.nv = p - vbuf;

+	setval(r, &kv);

+}

+

+static void

 initroot(Blk *r)

 {

 	char *p, kbuf[Keymax], vbuf[Inlmax];

@@ -15,16 +87,7 @@

 	Xdir d;

 	/* nb: values must be inserted in key order */

-	memset(&d, 0, sizeof(Xdir));

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

-	d.mode = DMDIR|0775;

-	d.atime = 0;

-	d.mtime = 0;

-	d.length = 0;

-	d.name = "";

-	d.uid = -1;

-	d.gid = -1;

-	d.muid = 0;

+	fillxdir(&d, Qmainroot, "", QTDIR, DMDIR|0775);

 	if(dir2kv(-1, &d, &kv, vbuf, sizeof(vbuf)) == -1)

 		sysfatal("ream: pack root: %r");

 	setval(r, &kv);

@@ -41,12 +104,20 @@

 }

 static void

-initsnap(Blk *s, Blk *r)

+initsnap(Blk *s, Blk *r, Blk *a)

 {

 	char *p, kbuf[Keymax], vbuf[Treesz];

 	Tree t;

 	Kvp kv;

+	p = packlabel(kbuf, sizeof(kbuf), "adm");

+	kv.k = kbuf;

+	kv.nk = p - kbuf;

+	p = packsnap(vbuf, sizeof(vbuf), 1);

+	kv.v = vbuf;

+	kv.nv = p - vbuf;

+	setval(s, &kv);

+

 	p = packlabel(kbuf, sizeof(kbuf), "empty");

 	kv.k = kbuf;

 	kv.nk = p - kbuf;

@@ -54,6 +125,7 @@

 	kv.v = vbuf;

 	kv.nv = p - vbuf;

 	setval(s, &kv);

+

 	p = packlabel(kbuf, sizeof(kbuf), "main");

 	kv.k = kbuf;

 	kv.nk = p - kbuf;

@@ -67,7 +139,7 @@

 	kv.nk = p - kbuf;

 	memset(&t, 0, sizeof(Tree));

-	t.nsucc = 0;

+	t.nsucc = 1;

 	t.nlbl = 2;

 	t.ht = 1;

 	t.gen = fs->nextgen++;

@@ -77,6 +149,22 @@

 	kv.v = vbuf;

 	kv.nv = p - vbuf;

 	setval(s, &kv);

+

+	p = packsnap(kbuf, sizeof(kbuf), 1);

+	kv.k = kbuf;

+	kv.nk = p - kbuf;

+

+	memset(&t, 0, sizeof(Tree));

+	t.nsucc = 0;

+	t.nlbl = 1;

+	t.ht = 1;

+	t.gen = fs->nextgen++;

+	t.prev = -1ULL;

+	t.bp = a->bp;

+	p = packtree(vbuf, sizeof(vbuf), &t);

+	kv.v = vbuf;

+	kv.nv = p - vbuf;

+	setval(s, &kv);

 }

 static void

@@ -135,9 +223,9 @@

 void

 reamfs(char *dev)

 {

+	Blk *sb, *mb, *ab, *ub;

 	vlong sz, asz, off;

-	Blk *rb, *tb;

-	Mount *mnt;

+	Mount *mnt, *adm;

 	Arena *a;

 	Dir *d;

 	int i;

@@ -155,6 +243,11 @@

 	if((mnt->root = mallocz(sizeof(Tree), 1)) == nil)

 		sysfatal("ream: alloc tree: %r");

+	if((adm = mallocz(sizeof(Mount), 1)) == nil)

+		sysfatal("ream: alloc mount: %r");

+	if((adm->root = mallocz(sizeof(Tree), 1)) == nil)

+		sysfatal("ream: alloc tree: %r");

+

 	fs->narena = (sz + 64ULL*GiB - 1) / (64ULL*GiB);

 	if(fs->narena < 8)

 		fs->narena = 8;

@@ -182,33 +275,53 @@

 		if(compresslog(a) == -1)

 			sysfatal("compress log: %r");

 	}

-	if((tb = newblk(mnt->root, Tleaf)) == nil)

+	if((mb = newblk(mnt->root, Tleaf)) == nil)

 		sysfatal("ream: allocate root: %r");

-	holdblk(tb);

-	initroot(tb);

-	finalize(tb);

-	syncblk(tb);

+	holdblk(mb);

+	initroot(mb);

+	finalize(mb);

+	syncblk(mb);

 	mnt->root->ht = 1;

-	mnt->root->bp = tb->bp;

+	mnt->root->bp = mb->bp;

+	if((ab = newblk(adm->root, Tleaf)) == nil)

+		sysfatal("ream: allocate root: %r");

+	if((ub = newblk(adm->root, Tdat)) == nil)

+		sysfatal("ream: allocate root: %r");

+	holdblk(ab);

+	holdblk(ub);

+	memcpy(ub->data, defaultusers, strlen(defaultusers));

+	finalize(ub);

+	syncblk(ub);

+	initadm(ab, ub);

+	finalize(ab);

+	syncblk(ab);

+

+	adm->root->ht = 1;

+	adm->root->bp = ab->bp;

+

 	/*

 	 * Now that we have a completely empty fs, give it

 	 * a single snap block that the tree will insert

 	 * into, and take a snapshot as the initial state.

 	 */

-	if((rb = newblk(mnt->root, Tleaf)) == nil)

+	if((sb = newblk(mnt->root, Tleaf)) == nil)

 		sysfatal("ream: allocate snaps: %r");

-	holdblk(rb);

-	initsnap(rb, tb);

-	finalize(rb);

-	syncblk(rb);

+	holdblk(sb);

+	initsnap(sb, mb, ab);

+	finalize(sb);

+	syncblk(sb);

-	fs->snap.bp = rb->bp;

+	fs->snap.bp = sb->bp;

 	fs->snap.ht = 1;

-	dropblk(tb);

-	dropblk(rb);

+	dropblk(mb);

+	dropblk(ab);

+	dropblk(ub);

+	dropblk(sb);

+	fs->nextqid = Nreamqid;

+

 	for(i = 0; i < fs->narena; i++){

 		a = &fs->arenas[i];

 		finalize(a->tail);

--- a/snap.c

+++ b/snap.c

@@ -315,7 +315,7 @@

 	Msg m[2];

 	int nm;

-	if(strcmp(name, "dump") == 0 || strcmp(name, "empty") == 0)

+	if(strcmp(name, "dump") == 0 || strcmp(name, "empty") == 0 || strcmp(name, "adm") == 0)

 		return Ename;

 	nm = 0;

@@ -363,7 +363,7 @@

 	char buf[2][Kvmax];

 	Msg m[2];

-	if(strcmp(name, "dump") == 0 || strcmp(name, "empty") == 0)

+	if(strcmp(name, "dump") == 0 || strcmp(name, "empty") == 0 || strcmp(name, "adm") == 0)

 		return Ename;

 	t->nlbl++;

 	m[0].op = Oinsert;

--- a/user.c

+++ b/user.c

@@ -6,18 +6,6 @@

 #include "dat.h"

 #include "fns.h"

-char *defaultusers =

-	"-1:adm::glenda\n"

-	"0:none::\n"

-	"1:tor:tor:\n"

-	"2:glenda:glenda:\n"

-	"10000:sys::\n"

-	"10001:map:map:\n"

-	"10002:doc::\n"

-	"10003:upas:upas:\n"

-	"10004:font::\n"

-	"10005:bootes:bootes:\n";

-

 static int

 walk1(Tree *t, vlong up, char *name, Qid *qid, vlong *len)

 {

@@ -260,13 +248,10 @@

 	vlong len;

 	Qid q;

-	s = defaultusers;

 	if(walk1(t, -1, "", &q, &len) == -1)

 		return Efs;

-	if(walk1(t, q.path, "adm", &q, &len) == -1)

-		goto Defaulted;

 	if(walk1(t, q.path, "users", &q, &len) == -1)

-		goto Defaulted;

+		return Eio;

 	if(q.type != QTFILE)

 		return Etype;

 	if(len >= 1*MiB)

@@ -273,9 +258,7 @@

 		return Efsize;

 	if((s = slurp(t, q.path, len)) == nil)

 		return Eio;

-Defaulted:

 	e = parseusers(fd, s);

-	if(s != defaultusers)

-		free(s);

+	free(s);

 	return e;

 }