r17293: After the results from the cluster tests in Germany,

fix the messaging code to call the efficient calls :

save_re_uid()
set_effective_uid(0);

messaging_op

restore_re_uid();

instead of using heavyweight become_root()/unbecome_root()
pairs around all messaging code. Fixup the messaging
code to ensure sec_init() is called (only once) so that non-root
processes still work when sending messages.

This is a lighter weight solution to become_root()/unbecome_root()
(which swaps all the supplemental groups) and should be more
efficient. I will migrate all server code over to using this
(a similar technique should be used in the passdb backend
where needed).

Jeremy.
(This used to be commit 4ace291278d9a44f5c577bdd3b282c1231e543df)

11 files changed, 32 insertions, 45 deletions

diff --git a/source3/lib/messages.c b/source3/lib/messages.c
index 57e4514b58..bae4052964 100644
--- a/source3/lib/messages.c
+++ b/source3/lib/messages.c
@@ -117,7 +117,10 @@ static void ping_message(int msg_type, struct process_id src,
 
 BOOL message_init(void)
 {
-	if (tdb) return True;
+	sec_init();
+
+	if (tdb)
+		return True;
 
 	tdb = tdb_open_log(lock_path("messages.tdb"), 
 		       0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
@@ -164,6 +167,10 @@ static TDB_DATA message_key_pid(struct process_id pid)
 static BOOL message_notify(struct process_id procid)
 {
 	pid_t pid = procid.pid;
+	int saved_errno;
+	int ret;
+	uid_t euid = geteuid();
+
 	/*
 	 * Doing kill with a non-positive pid causes messages to be
 	 * sent to places we don't want.
@@ -171,15 +178,28 @@ static BOOL message_notify(struct process_id procid)
 
 	SMB_ASSERT(pid > 0);
 
-	if (kill(pid, SIGUSR1) == -1) {
-		if (errno == ESRCH) {
+	if (euid != 0) {
+	        save_re_uid();
+		set_effective_uid(0);
+	}
+
+	ret = kill(pid, SIGUSR1);
+	saved_errno = errno;
+
+	if (euid != 0) {
+		restore_re_uid();
+	}
+
+	if (ret == -1) {
+		if (saved_errno == ESRCH) {
 			DEBUG(2,("pid %d doesn't exist - deleting messages record\n", (int)pid));
 			tdb_delete(tdb, message_key_pid(procid));
 		} else {
-			DEBUG(2,("message to process %d failed - %s\n", (int)pid, strerror(errno)));
+			DEBUG(2,("message to process %d failed - %s\n", (int)pid, strerror(saved_errno)));
 		}
 		return False;
 	}
+
 	return True;
 }
 
diff --git a/source3/lib/tallocmsg.c b/source3/lib/tallocmsg.c
index b515093cd6..e4364f1ff7 100644
--- a/source3/lib/tallocmsg.c
+++ b/source3/lib/tallocmsg.c
@@ -44,10 +44,8 @@ void msg_pool_usage(int msg_type, struct process_id src_pid,
 		return;
 	}
 	
-	become_root();
 	message_send_pid(src_pid, MSG_POOL_USAGE,
 			 reply, strlen(reply)+1, True);
-	unbecome_root();
 
 	SAFE_FREE(reply);
 }
diff --git a/source3/lib/util_sec.c b/source3/lib/util_sec.c
index 26be27ea51..c13b20ec92 100644
--- a/source3/lib/util_sec.c
+++ b/source3/lib/util_sec.c
@@ -52,10 +52,16 @@ static gid_t initial_gid;
 remember what uid we got started as - this allows us to run correctly
 as non-root while catching trapdoor systems
 ****************************************************************************/
+
 void sec_init(void)
 {
-	initial_uid = geteuid();
-	initial_gid = getegid();
+	static int initialized;
+
+	if (!initialized) {
+		initial_uid = geteuid();
+		initial_gid = getegid();
+		initialized = 1;
+	}
 }
 
 /****************************************************************************
diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 031836ecdf..4a36d938ad 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -816,11 +816,9 @@ static BOOL brl_unlock_windows(struct byte_range_lock *br_lck, const struct lock
 			DEBUG(10,("brl_unlock: sending unlock message to pid %s\n",
 				procid_str_static(&pend_lock->context.pid )));
 
-			become_root();
 			message_send_pid(pend_lock->context.pid,
 					MSG_SMB_UNLOCK,
 					NULL, 0, True);
-			unbecome_root();
 		}
 	}
 
@@ -985,11 +983,9 @@ static BOOL brl_unlock_posix(struct byte_range_lock *br_lck, const struct lock_s
 			DEBUG(10,("brl_unlock: sending unlock message to pid %s\n",
 				procid_str_static(&pend_lock->context.pid )));
 
-			become_root();
 			message_send_pid(pend_lock->context.pid,
 					MSG_SMB_UNLOCK,
 					NULL, 0, True);
-			unbecome_root();
 		}
 	}
 
@@ -1306,11 +1302,9 @@ void brl_close_fnum(struct byte_range_lock *br_lck)
 
 				/* We could send specific lock info here... */
 				if (brl_pending_overlap(lock, pend_lock)) {
-					become_root();
 					message_send_pid(pend_lock->context.pid,
 							MSG_SMB_UNLOCK,
 							NULL, 0, True);
-					unbecome_root();
 				}
 			}
 
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index 3cbf318007..3879d40cba 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -851,10 +851,8 @@ BOOL rename_share_filename(struct share_mode_lock *lck,
 			(unsigned int)lck->dev, (double)lck->ino,
 			lck->servicepath, lck->filename ));
 
-		become_root();
 		message_send_pid(se->pid, MSG_SMB_FILE_RENAME,
 				frm, msg_len, True);
-		unbecome_root();
 	}
 
 	return True;
diff --git a/source3/printing/printing.c b/source3/printing/printing.c
index bb756c8870..fbb8166565 100644
--- a/source3/printing/printing.c
+++ b/source3/printing/printing.c
@@ -1535,10 +1535,8 @@ static void print_queue_update(int snum, BOOL force)
 
 	/* finally send the message */
 	
-	become_root();
 	message_send_pid(pid_to_procid(background_lpq_updater_pid),
 		 MSG_PRINTER_UPDATE, buffer, len, False);
-	unbecome_root();
 
 	SAFE_FREE( buffer );
 
diff --git a/source3/rpc_server/srv_srvsvc_nt.c b/source3/rpc_server/srv_srvsvc_nt.c
index e4e5bde215..de3148aae8 100644
--- a/source3/rpc_server/srv_srvsvc_nt.c
+++ b/source3/rpc_server/srv_srvsvc_nt.c
@@ -1303,7 +1303,6 @@ WERROR _srv_net_sess_del(pipes_struct *p, SRV_Q_NET_SESS_DEL *q_u, SRV_R_NET_SES
 	int num_sessions, snum;
 	fstring username;
 	fstring machine;
-	BOOL not_root = False;
 
 	rpcstr_pull_unistr2_fstring(username, &q_u->uni_user_name);
 	rpcstr_pull_unistr2_fstring(machine, &q_u->uni_cli_name);
@@ -1332,16 +1331,8 @@ WERROR _srv_net_sess_del(pipes_struct *p, SRV_Q_NET_SESS_DEL *q_u, SRV_R_NET_SES
 		if ((strequal(session_list[snum].username, username) || username[0] == '\0' ) &&
 		    strequal(session_list[snum].remote_machine, machine)) {
 		
-			if (p->pipe_user.ut.uid != sec_initial_uid()) {
-				not_root = True;
-				become_root();
-			}
-
 			if (message_send_pid(pid_to_procid(session_list[snum].pid), MSG_SHUTDOWN, NULL, 0, False))
 				r_u->status = WERR_OK;
-
-			if (not_root) 
-				unbecome_root();
 		}
 	}
 
diff --git a/source3/smbd/blocking.c b/source3/smbd/blocking.c
index a0b93f5032..ed57c9f621 100644
--- a/source3/smbd/blocking.c
+++ b/source3/smbd/blocking.c
@@ -837,9 +837,6 @@ BOOL blocking_lock_cancel(files_struct *fsp,
 	memcpy(msg, &blr, sizeof(blr));
 	memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
 
-	/* Don't need to be root here as we're only ever
-		sending to ourselves. */
-
 	message_send_pid(pid_to_procid(sys_getpid()),
 			MSG_SMB_BLOCKING_LOCK_CANCEL,
 			&msg, sizeof(msg), True);
diff --git a/source3/smbd/close.c b/source3/smbd/close.c
index 08e4a24a56..a3ddcae11d 100644
--- a/source3/smbd/close.c
+++ b/source3/smbd/close.c
@@ -134,10 +134,8 @@ static void notify_deferred_opens(struct share_mode_lock *lck)
 
 			share_mode_entry_to_message(msg, e);
 
-			become_root();
  			message_send_pid(e->pid, MSG_SMB_OPEN_RETRY,
  					 msg, MSG_SMB_SHARE_MODE_ENTRY_SIZE, True);
-			unbecome_root();
  		}
  	}
 }
diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index ef59da6447..5c10c59054 100644
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -713,10 +713,8 @@ static BOOL delay_for_oplocks(struct share_mode_lock *lck,
 		SSVAL(msg,6,exclusive->op_type | FORCE_OPLOCK_BREAK_TO_NONE);
 	}
 
-	become_root();
 	ret = message_send_pid(exclusive->pid, MSG_SMB_BREAK_REQUEST,
 			       msg, MSG_SMB_SHARE_MODE_ENTRY_SIZE, True);
-	unbecome_root();
 	if (!ret) {
 		DEBUG(3, ("Could not send oplock break message\n"));
 	}
diff --git a/source3/smbd/oplock.c b/source3/smbd/oplock.c
index 99ce79296f..d9850ee051 100644
--- a/source3/smbd/oplock.c
+++ b/source3/smbd/oplock.c
@@ -504,13 +504,10 @@ static void process_oplock_break_message(int msg_type, struct process_id src,
 		 * get to process this message, we have closed the file. Reply
 		 * with 'ok, oplock broken' */
 		DEBUG(3, ("Did not find fsp\n"));
-		become_root();
 
 		/* We just send the same message back. */
 		message_send_pid(src, MSG_SMB_BREAK_RESPONSE,
 				 buf, MSG_SMB_SHARE_MODE_ENTRY_SIZE, True);
-
-		unbecome_root();
 		return;
 	}
 
@@ -529,13 +526,9 @@ static void process_oplock_break_message(int msg_type, struct process_id src,
 		DEBUG(3, ("Already downgraded oplock on 0x%x/%.0f: %s\n",
 			  (unsigned int)fsp->dev, (double)fsp->inode,
 			  fsp->fsp_name));
-		become_root();
-
 		/* We just send the same message back. */
 		message_send_pid(src, MSG_SMB_BREAK_RESPONSE,
 				 buf, MSG_SMB_SHARE_MODE_ENTRY_SIZE, True);
-
-		unbecome_root();
 		return;
 	}
 
@@ -656,7 +649,6 @@ void reply_to_oplock_break_requests(files_struct *fsp)
 {
 	int i;
 
-	become_root();
 	for (i=0; i<fsp->num_pending_break_messages; i++) {
 		struct share_mode_entry *e = &fsp->pending_break_messages[i];
 		char msg[MSG_SMB_SHARE_MODE_ENTRY_SIZE];
@@ -666,7 +658,6 @@ void reply_to_oplock_break_requests(files_struct *fsp)
 		message_send_pid(e->pid, MSG_SMB_BREAK_RESPONSE,
 				 msg, MSG_SMB_SHARE_MODE_ENTRY_SIZE, True);
 	}
-	unbecome_root();
 
 	SAFE_FREE(fsp->pending_break_messages);
 	fsp->num_pending_break_messages = 0;
@@ -801,10 +792,8 @@ void release_level_2_oplocks_on_change(files_struct *fsp)
 
 		share_mode_entry_to_message(msg, share_entry);
 
-		become_root();
 		message_send_pid(share_entry->pid, MSG_SMB_ASYNC_LEVEL2_BREAK,
 				 msg, MSG_SMB_SHARE_MODE_ENTRY_SIZE, True);
-		unbecome_root();
 	}
 
 	/* We let the message receivers handle removing the oplock state