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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 | ||
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15 | #include "daemon-client.h" |
16 | ||
17 | #ifndef _LVM_DAEMON_COMMON_SERVER_H | |
18 | #define _LVM_DAEMON_COMMON_SERVER_H | |
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19 | |
20 | typedef struct { | |
21 | int socket_fd; /* the fd we use to talk to the client */ | |
22 | pthread_t thread_id; | |
23 | char *read_buf; | |
24 | void *private; /* this holds per-client state */ | |
25 | } client_handle; | |
26 | ||
27 | typedef struct { | |
c033ea01 | 28 | struct dm_config_tree *cft; |
92658f56 | 29 | char *buffer; |
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30 | } request; |
31 | ||
32 | typedef struct { | |
33 | int error; | |
c033ea01 | 34 | struct dm_config_tree *cft; |
92658f56 | 35 | char *buffer; |
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36 | } response; |
37 | ||
38 | struct daemon_state; | |
39 | ||
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40 | /* |
41 | * Craft a simple reply, without the need to construct a config_tree. See | |
42 | * daemon_send_simple in daemon-client.h for the description of the parameters. | |
43 | */ | |
e68a6fbf | 44 | response daemon_reply_simple(const char *id, ...); |
aaca7f11 | 45 | |
94bb67ab | 46 | static inline int daemon_request_int(request r, const char *path, int def) { |
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47 | if (!r.cft) |
48 | return def; | |
c033ea01 | 49 | return dm_config_find_int(r.cft->root, path, def); |
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50 | } |
51 | ||
52 | static inline const char *daemon_request_str(request r, const char *path, const char *def) { | |
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53 | if (!r.cft) |
54 | return def; | |
c033ea01 | 55 | return dm_config_find_str(r.cft->root, path, def); |
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56 | } |
57 | ||
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58 | /* |
59 | * The callback. Called once per request issued, in the respective client's | |
60 | * thread. It is presented by a parsed request (in the form of a config tree). | |
61 | * The output is a new config tree that is serialised and sent back to the | |
62 | * client. The client blocks until the request processing is done and reply is | |
63 | * sent. | |
64 | */ | |
65 | typedef response (*handle_request)(struct daemon_state s, client_handle h, request r); | |
66 | ||
67 | typedef struct daemon_state { | |
d7448a72 PR |
68 | /* |
69 | * The maximal stack size for individual daemon threads. This is | |
70 | * essential for daemons that need to be locked into memory, since | |
71 | * pthread's default is 10M per thread. | |
72 | */ | |
73 | int thread_stack_size; | |
74 | ||
75 | /* Flags & attributes affecting the behaviour of the daemon. */ | |
76 | unsigned avoid_oom:1; | |
77 | unsigned foreground:1; | |
78 | const char *name; | |
79 | const char *pidfile; | |
73ffd6e7 | 80 | const char *socket_path; |
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81 | int log_level; |
82 | handle_request handler; | |
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83 | int (*daemon_init)(struct daemon_state *st); |
84 | int (*daemon_fini)(struct daemon_state *st); | |
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85 | |
86 | /* Global runtime info maintained by the framework. */ | |
87 | int socket_fd; | |
d7448a72 | 88 | |
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89 | void *private; /* the global daemon state */ |
90 | } daemon_state; | |
91 | ||
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92 | /* |
93 | * Start serving the requests. This does all the daemonisation, socket setup | |
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94 | * work and so on. This function takes over the process, and upon failure, it |
95 | * will terminate execution. It may be called at most once. | |
56517bad | 96 | */ |
dc85d3fb | 97 | void daemon_start(daemon_state s); |
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98 | |
99 | /* | |
100 | * Take over from an already running daemon. This function handles connecting | |
101 | * to the running daemon and telling it we are going to take over. The takeover | |
102 | * request may be customised by passing in a non-NULL request. | |
103 | * | |
104 | * The takeover sequence: the old daemon stops accepting new clients, then it | |
105 | * waits until all current client connections are closed. When that happens, it | |
106 | * serializes its current state and sends that as a reply, which is then | |
107 | * returned by this function (therefore, this function won't return until the | |
108 | * previous instance has shut down). | |
109 | * | |
110 | * The daemon, after calling daemon_takeover is expected to set up its | |
111 | * daemon_state using the reply from this function and call daemon_start as | |
112 | * usual. | |
113 | */ | |
114 | daemon_reply daemon_takeover(daemon_info i, daemon_request r); | |
115 | ||
116 | /* Call this to request a clean shutdown of the daemon. Async safe. */ | |
08a95743 | 117 | void daemon_stop(void); |
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118 | |
119 | #endif |