2 This file is part of GNUnet.
3 (C) 2011, 2012 Christian Grothoff
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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22 * @file include/gnunet_helper_lib.h
23 * @brief API for dealing with (SUID) helper processes that communicate via GNUNET_MessageHeaders on stdin/stdout
24 * @author Philipp Toelke
25 * @author Christian Grothoff
28 #ifndef GNUNET_HELPER_LIB_H
29 #define GNUNET_HELPER_LIB_H
31 #include "gnunet_scheduler_lib.h"
32 #include "gnunet_server_lib.h"
35 * The handle to a helper process.
37 struct GNUNET_HELPER_Handle;
41 * Callback that will be called when the helper process dies. This is not called
42 * when the helper process is stoped using GNUNET_HELPER_stop()
44 * @param cls the closure from GNUNET_HELPER_start()
46 typedef void (*GNUNET_HELPER_ExceptionCallback) (void *cls);
50 * Starts a helper and begins reading from it. The helper process is
51 * restarted when it dies except when it is stopped using GNUNET_HELPER_stop()
52 * or when the exp_cb callback is not NULL.
54 * @param with_control_pipe does the helper support the use of a control pipe for signalling?
55 * @param binary_name name of the binary to run
56 * @param binary_argv NULL-terminated list of arguments to give when starting the binary (this
57 * argument must not be modified by the client for
58 * the lifetime of the helper handle)
59 * @param cb function to call if we get messages from the helper
60 * @param exp_cb the exception callback to call. Set this to NULL if the helper
61 * process has to be restarted automatically when it dies/crashes
62 * @param cb_cls closure for the above callbacks
63 * @return the new Handle, NULL on error
65 struct GNUNET_HELPER_Handle *
66 GNUNET_HELPER_start (int with_control_pipe,
67 const char *binary_name,
68 char *const binary_argv[],
69 GNUNET_SERVER_MessageTokenizerCallback cb,
70 GNUNET_HELPER_ExceptionCallback exp_cb,
75 * Kills the helper, closes the pipe and frees the handle
77 * @param h handle to helper to stop
80 GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h);
84 * Kills the helper by closing its stdin (the helper is expected to catch the
85 * resulting SIGPIPE and shutdown), closes the pipe and frees the handle
87 * @param h handle to helper to stop
90 GNUNET_HELPER_soft_stop (struct GNUNET_HELPER_Handle *h);
94 * Continuation function.
97 * @param result GNUNET_OK on success,
98 * GNUNET_NO if helper process died
99 * GNUNET_SYSERR during GNUNET_HELPER_stop
101 typedef void (*GNUNET_HELPER_Continuation)(void *cls,
106 * Handle to cancel 'send'
108 struct GNUNET_HELPER_SendHandle;
112 * Send an message to the helper.
114 * @param h helper to send message to
115 * @param msg message to send
116 * @param can_drop can the message be dropped if there is already one in the queue?
117 * @param cont continuation to run once the message is out
118 * @param cont_cls closure for 'cont'
119 * @return NULL if the message was dropped,
120 * otherwise handle to cancel *cont* (actual transmission may
123 struct GNUNET_HELPER_SendHandle *
124 GNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h,
125 const struct GNUNET_MessageHeader *msg,
127 GNUNET_HELPER_Continuation cont,
132 * Cancel a 'send' operation. If possible, transmitting the
133 * message is also aborted, but at least 'cont' won't be
136 * @param sh operation to cancel
139 GNUNET_HELPER_send_cancel (struct GNUNET_HELPER_SendHandle *sh);
141 #endif /* end of include guard: GNUNET_HELPER_LIB_H */