2 This file is part of GNUnet.
3 Copyright (C) 2011, 2012 Christian Grothoff
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
8 or (at your 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 Affero General Public License for more details.
17 * @author Philipp Toelke
18 * @author Christian Grothoff
21 * API for dealing with SUID helper processes
23 * @defgroup helper Helper library
24 * Dealing with SUID helper processes.
26 * Provides an API for dealing with (SUID) helper processes
27 * that communicate via GNUNET_MessageHeaders on STDIN/STDOUT.
32 #ifndef GNUNET_HELPER_LIB_H
33 #define GNUNET_HELPER_LIB_H
35 #include "gnunet_scheduler_lib.h"
36 #include "gnunet_mst_lib.h"
40 * The handle to a helper process.
42 struct GNUNET_HELPER_Handle;
46 * Callback that will be called when the helper process dies. This is not called
47 * when the helper process is stoped using GNUNET_HELPER_stop()
49 * @param cls the closure from GNUNET_HELPER_start()
52 (*GNUNET_HELPER_ExceptionCallback) (void *cls);
56 * Starts a helper and begins reading from it. The helper process is
57 * restarted when it dies except when it is stopped using GNUNET_HELPER_stop()
58 * or when the exp_cb callback is not NULL.
60 * @param with_control_pipe does the helper support the use of a control pipe for signalling?
61 * @param binary_name name of the binary to run
62 * @param binary_argv NULL-terminated list of arguments to give when starting the binary (this
63 * argument must not be modified by the client for
64 * the lifetime of the helper handle)
65 * @param cb function to call if we get messages from the helper
66 * @param exp_cb the exception callback to call. Set this to NULL if the helper
67 * process has to be restarted automatically when it dies/crashes
68 * @param cb_cls closure for the above callbacks
69 * @return the new Handle, NULL on error
71 struct GNUNET_HELPER_Handle *
72 GNUNET_HELPER_start (int with_control_pipe,
73 const char *binary_name,
74 char *const binary_argv[],
75 GNUNET_MessageTokenizerCallback cb,
76 GNUNET_HELPER_ExceptionCallback exp_cb,
81 * Sends termination signal to the helper process. The helper process is not
82 * reaped; call GNUNET_HELPER_wait() for reaping the dead helper process.
84 * @param h the helper handle
85 * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
86 * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
87 * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
90 GNUNET_HELPER_kill (struct GNUNET_HELPER_Handle *h, int soft_kill);
94 * Reap the helper process. This call is blocking (!). The helper process
95 * should either be sent a termination signal before or should be dead before
96 * calling this function
98 * @param h the helper handle
99 * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
102 GNUNET_HELPER_wait (struct GNUNET_HELPER_Handle *h);
106 * Free's the resources occupied by the helper handle
108 * @param h the helper handle to free
111 GNUNET_HELPER_destroy (struct GNUNET_HELPER_Handle *h);
115 * Kills the helper, closes the pipe, frees the handle and calls wait() on the
118 * @param h handle to helper to stop
119 * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
120 * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
123 GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h, int soft_kill);
127 * Continuation function.
130 * @param result #GNUNET_OK on success,
131 * #GNUNET_NO if helper process died
132 * #GNUNET_SYSERR during GNUNET_HELPER_destroy
134 typedef void (*GNUNET_HELPER_Continuation)(void *cls,
139 * Handle to cancel 'send'
141 struct GNUNET_HELPER_SendHandle;
145 * Send an message to the helper.
147 * @param h helper to send message to
148 * @param msg message to send
149 * @param can_drop can the message be dropped if there is already one in the queue?
150 * @param cont continuation to run once the message is out (#GNUNET_OK on succees, #GNUNET_NO
151 * if the helper process died, #GNUNET_SYSERR during #GNUNET_HELPER_destroy).
152 * @param cont_cls closure for @a cont
153 * @return NULL if the message was dropped,
154 * otherwise handle to cancel @a cont (actual transmission may
157 struct GNUNET_HELPER_SendHandle *
158 GNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h,
159 const struct GNUNET_MessageHeader *msg,
161 GNUNET_HELPER_Continuation cont,
166 * Cancel a #GNUNET_HELPER_send operation. If possible, transmitting
167 * the message is also aborted, but at least 'cont' won't be called.
169 * @param sh operation to cancel
172 GNUNET_HELPER_send_cancel (struct GNUNET_HELPER_SendHandle *sh);
176 /* end of include guard: GNUNET_HELPER_LIB_H */
178 /** @} */ /* end of group */