1 #ifndef GIT_SIMPLE_IPC_H
2 #define GIT_SIMPLE_IPC_H
5 * See Documentation/technical/api-simple-ipc.txt
8 #ifdef SUPPORTS_SIMPLE_IPC
12 * Simple IPC Client Side API.
15 enum ipc_active_state
{
17 * The pipe/socket exists and the daemon is waiting for connections.
19 IPC_STATE__LISTENING
= 0,
22 * The pipe/socket exists, but the daemon is not listening.
23 * Perhaps it is very busy.
24 * Perhaps the daemon died without deleting the path.
25 * Perhaps it is shutting down and draining existing clients.
26 * Perhaps it is dead, but other clients are lingering and
27 * still holding a reference to the pathname.
29 IPC_STATE__NOT_LISTENING
,
32 * The requested pathname is bogus and no amount of retries
35 IPC_STATE__INVALID_PATH
,
38 * The requested pathname is not found. This usually means
39 * that there is no daemon present.
41 IPC_STATE__PATH_NOT_FOUND
,
43 IPC_STATE__OTHER_ERROR
,
46 struct ipc_client_connect_options
{
48 * Spin under timeout if the server is running but can't
49 * accept our connection yet. This should always be set
50 * unless you just want to poke the server and see if it
53 unsigned int wait_if_busy
:1;
56 * Spin under timeout if the pipe/socket is not yet present
57 * on the file system. This is useful if we just started
58 * the service and need to wait for it to become ready.
60 unsigned int wait_if_not_found
:1;
63 * Disallow chdir() when creating a Unix domain socket.
65 unsigned int uds_disallow_chdir
:1;
68 #define IPC_CLIENT_CONNECT_OPTIONS_INIT { \
70 .wait_if_not_found = 0, \
71 .uds_disallow_chdir = 0, \
75 * Determine if a server is listening on this named pipe or socket using
76 * platform-specific logic. This might just probe the filesystem or it
77 * might make a trivial connection to the server using this pathname.
79 enum ipc_active_state
ipc_get_active_state(const char *path
);
81 struct ipc_client_connection
{
86 * Try to connect to the daemon on the named pipe or socket.
88 * Returns IPC_STATE__LISTENING and a connection handle.
90 * Otherwise, returns info to help decide whether to retry or to
91 * spawn/respawn the server.
93 enum ipc_active_state
ipc_client_try_connect(
95 const struct ipc_client_connect_options
*options
,
96 struct ipc_client_connection
**p_connection
);
98 void ipc_client_close_connection(struct ipc_client_connection
*connection
);
101 * Used by the client to synchronously send and receive a message with
102 * the server on the provided client connection.
104 * Returns 0 when successful.
106 * Calls error() and returns non-zero otherwise.
108 int ipc_client_send_command_to_connection(
109 struct ipc_client_connection
*connection
,
110 const char *message
, struct strbuf
*answer
);
113 * Used by the client to synchronously connect and send and receive a
114 * message to the server listening at the given path.
116 * Returns 0 when successful.
118 * Calls error() and returns non-zero otherwise.
120 int ipc_client_send_command(const char *path
,
121 const struct ipc_client_connect_options
*options
,
122 const char *message
, struct strbuf
*answer
);
125 * Simple IPC Server Side API.
128 struct ipc_server_reply_data
;
130 typedef int (ipc_server_reply_cb
)(struct ipc_server_reply_data
*,
131 const char *response
,
132 size_t response_len
);
135 * Prototype for an application-supplied callback to process incoming
136 * client IPC messages and compose a reply. The `application_cb` should
137 * use the provided `reply_cb` and `reply_data` to send an IPC response
138 * back to the client. The `reply_cb` callback can be called multiple
139 * times for chunking purposes. A reply message is optional and may be
140 * omitted if not necessary for the application.
142 * The return value from the application callback is ignored.
143 * The value `SIMPLE_IPC_QUIT` can be used to shutdown the server.
145 typedef int (ipc_server_application_cb
)(void *application_data
,
147 ipc_server_reply_cb
*reply_cb
,
148 struct ipc_server_reply_data
*reply_data
);
150 #define SIMPLE_IPC_QUIT -2
153 * Opaque instance data to represent an IPC server instance.
155 struct ipc_server_data
;
158 * Control parameters for the IPC server instance.
159 * Use this to hide platform-specific settings.
161 struct ipc_server_opts
166 * Disallow chdir() when creating a Unix domain socket.
168 unsigned int uds_disallow_chdir
:1;
172 * Start an IPC server instance in one or more background threads
173 * and return a handle to the pool.
175 * Returns 0 if the asynchronous server pool was started successfully.
177 * Returns -2 if we could not startup because another server is using
178 * the socket or named pipe.
180 * When a client IPC message is received, the `application_cb` will be
181 * called (possibly on a random thread) to handle the message and
182 * optionally compose a reply message.
184 int ipc_server_run_async(struct ipc_server_data
**returned_server_data
,
185 const char *path
, const struct ipc_server_opts
*opts
,
186 ipc_server_application_cb
*application_cb
,
187 void *application_data
);
190 * Gently signal the IPC server pool to shutdown. No new client
191 * connections will be accepted, but existing connections will be
192 * allowed to complete.
194 int ipc_server_stop_async(struct ipc_server_data
*server_data
);
197 * Block the calling thread until all threads in the IPC server pool
198 * have completed and been joined.
200 int ipc_server_await(struct ipc_server_data
*server_data
);
203 * Close and free all resource handles associated with the IPC server
206 void ipc_server_free(struct ipc_server_data
*server_data
);
209 * Run an IPC server instance and block the calling thread of the
210 * current process. It does not return until the IPC server has
211 * either shutdown or had an unrecoverable error.
213 * The IPC server handles incoming IPC messages from client processes
214 * and may use one or more background threads as necessary.
216 * Returns 0 after the server has completed successfully.
217 * Returns -1 if the server cannot be started.
218 * Returns -2 if we could not startup because another server is using
219 * the socket or named pipe.
221 * When a client IPC message is received, the `application_cb` will be
222 * called (possibly on a random thread) to handle the message and
223 * optionally compose a reply message.
225 * Note that `ipc_server_run()` is a synchronous wrapper around the
226 * above asynchronous routines. It effectively hides all of the
227 * server state and thread details from the caller and presents a
228 * simple synchronous interface.
230 int ipc_server_run(const char *path
, const struct ipc_server_opts
*opts
,
231 ipc_server_application_cb
*application_cb
,
232 void *application_data
);
234 #endif /* SUPPORTS_SIMPLE_IPC */
235 #endif /* GIT_SIMPLE_IPC_H */