cwfs: add optional uid argument to allow command, unify permission override code

the allow command now takes an optional uid argument for the user
to be granted temporary god status on the fileserver for maintenance.

this was kenji okomotos idea, so thanks :)

remove wstatallow and writeallow flags. instead, we have global:

int allowed;

that contains the uid of the currently allowed user id or -1
if permission checking is globally disabled for the fileserver.
when zero, normal permission checking takes place.

added int isallowed(File*) function that returns non-zero when the
context is the console, or the allowed user. this is also used internally
by iaccess(), so all the extra code of in the callers of iaccess()
is gone now.

dont conflate allowed user with noauth flag and auto-allow on ream.
the installer already knows about noauth and allow flags so theres no
problem with bootstraping.

1 files changed, 21 insertions, 5 deletions

diff --git a/sys/src/cmd/cwfs/con.c b/sys/src/cmd/cwfs/con.c
index 00fadf6bb..bace9df29 100644
--- a/sys/src/cmd/cwfs/con.c
+++ b/sys/src/cmd/cwfs/con.c
@@ -461,15 +461,31 @@ cmd_clri(int argc, char *argv[])
 }
 
 static void
-cmd_allow(int, char**)
+cmd_allow(int argc, char *argv[])
 {
-	wstatallow = writeallow = 1;
+	char *name;
+	int uid;
+
+	uid = -1;
+	name = "any user";
+	if(argc > 1){
+		name = argv[1];
+		uid = strtouid(name);
+		if(uid < 0)
+			uid = number(name, -2, 10);
+		if(uid < 0) {
+			print("bad uid %s\n", name);
+			return;
+		}
+	}
+	print("allowed %s\n", name);
+	allowed = uid;
 }
 
 static void
 cmd_disallow(int, char**)
 {
-	wstatallow = writeallow = 0;
+	allowed = 0;
 }
 
 void
@@ -748,14 +764,14 @@ cmd_chatty(int argc, char *argv[])
 static void
 installcmds(void)
 {
-	cmd_install("allow", "-- disable permission checking", cmd_allow);
+	cmd_install("allow", "[uid] -- disable permission checking", cmd_allow);
 	cmd_install("cfs", "[file] -- set current filesystem", cmd_cfs);
 	cmd_install("chatty", "n -- set chattiness", cmd_chatty);
 	cmd_install("clean", "file [bno [addr]] -- block print/fix", cmd_clean);
 	cmd_install("check", "[options]", cmd_check);
 	cmd_install("clri", "[file ...] -- purge files/dirs", cmd_clri);
 	cmd_install("create", "path uid gid perm [lad] -- make a file/dir", cmd_create);
-	cmd_install("disallow", "-- enable permission checking", cmd_disallow);
+	cmd_install("disallow", "-- (re)enable permission checking", cmd_disallow);
 	cmd_install("duallow", "uid -- duallow", cmd_duallow);
 	cmd_install("flag", "-- print set flags", cmd_flag);
 	cmd_install("fstat", "path -- print info on a file/dir", cmd_fstat);