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1 | /* |
2 | * Copyright (C) 2011 Red Hat, Inc. All rights reserved. | |
3 | * | |
4 | * This file is part of LVM2. | |
5 | * | |
6 | * This copyrighted material is made available to anyone wishing to use, | |
7 | * modify, copy, or redistribute it subject to the terms and conditions | |
8 | * of the GNU Lesser General Public License v.2.1. | |
9 | * | |
10 | * You should have received a copy of the GNU Lesser General Public License | |
11 | * along with this program; if not, write to the Free Software Foundation, | |
12 | * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
13 | */ | |
14 | ||
15 | #ifndef _LVM_DAEMON_COMMON_CLIENT_H | |
16 | #define _LVM_DAEMON_COMMON_CLIENT_H | |
17 | ||
18 | typedef struct { | |
19 | int socket_fd; /* the fd we use to talk to the client */ | |
20 | pthread_t thread_id; | |
21 | char *read_buf; | |
22 | void *private; /* this holds per-client state */ | |
23 | } client_handle; | |
24 | ||
25 | typedef struct { | |
d7448a72 PR |
26 | /* |
27 | * The maximal stack size for individual daemon threads. This is | |
28 | * essential for daemons that need to be locked into memory, since | |
29 | * pthread's default is 10M per thread. | |
30 | */ | |
31 | int thread_stack_size; | |
32 | ||
33 | /* Flags & attributes affecting the behaviour of the daemon. */ | |
34 | unsigned avoid_oom:1; | |
35 | unsigned foreground:1; | |
36 | const char *name; | |
37 | const char *pidfile; | |
73ffd6e7 PR |
38 | const char *socket_path; |
39 | ||
40 | /* Global runtime info maintained by the framework. */ | |
41 | int socket_fd; | |
d7448a72 | 42 | |
56517bad PR |
43 | void *private; /* the global daemon state */ |
44 | } daemon_state; | |
45 | ||
46 | typedef struct { | |
47 | struct config_tree *cft; | |
48 | } request; | |
49 | ||
50 | typedef struct { | |
51 | struct config_tree *cft; | |
52 | } response; | |
53 | ||
54 | /* | |
55 | * The callback. Called once per request issued, in the respective client's | |
56 | * thread. It is presented by a parsed request (in the form of a config tree). | |
57 | * The output is a new config tree that is serialised and sent back to the | |
58 | * client. The client blocks until the request processing is done and reply is | |
59 | * sent. | |
60 | */ | |
61 | typedef response (*handle_request)(daemon_state s, client_handle h, request r); | |
62 | ||
63 | /* | |
64 | * Start serving the requests. This does all the daemonisation, socket setup | |
d7448a72 PR |
65 | * work and so on. This function takes over the process, and upon failure, it |
66 | * will terminate execution. It may be called at most once. | |
56517bad PR |
67 | */ |
68 | void daemon_start(daemon_state s, handle_request r); | |
69 | ||
70 | /* | |
71 | * Take over from an already running daemon. This function handles connecting | |
72 | * to the running daemon and telling it we are going to take over. The takeover | |
73 | * request may be customised by passing in a non-NULL request. | |
74 | * | |
75 | * The takeover sequence: the old daemon stops accepting new clients, then it | |
76 | * waits until all current client connections are closed. When that happens, it | |
77 | * serializes its current state and sends that as a reply, which is then | |
78 | * returned by this function (therefore, this function won't return until the | |
79 | * previous instance has shut down). | |
80 | * | |
81 | * The daemon, after calling daemon_takeover is expected to set up its | |
82 | * daemon_state using the reply from this function and call daemon_start as | |
83 | * usual. | |
84 | */ | |
85 | daemon_reply daemon_takeover(daemon_info i, daemon_request r); | |
86 | ||
87 | /* Call this to request a clean shutdown of the daemon. Async safe. */ | |
88 | void daemon_stop(); | |
89 | ||
90 | #endif |