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Diffstat (limited to 'src/util/child_management.c')
-rw-r--r-- | src/util/child_management.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/src/util/child_management.c b/src/util/child_management.c new file mode 100644 index 000000000..7edc33dc1 --- /dev/null +++ b/src/util/child_management.c | |||
@@ -0,0 +1,219 @@ | |||
1 | /* | ||
2 | This file is part of GNUnet | ||
3 | Copyright (C) 2021 GNUnet e.V. | ||
4 | |||
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. | ||
9 | |||
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. | ||
14 | |||
15 | You should have received a copy of the GNU Affero General Public License | ||
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
17 | |||
18 | SPDX-License-Identifier: AGPL3.0-or-later | ||
19 | */ | ||
20 | |||
21 | /** | ||
22 | * @file testing/child_management.c | ||
23 | * @brief Handling of child processes in GNUnet. | ||
24 | * @author Christian Grothoff (ANASTASIS) | ||
25 | * @author Dominik Meister (ANASTASIS) | ||
26 | * @author t3sserakt | ||
27 | */ | ||
28 | #include "platform.h" | ||
29 | #include "gnunet_util_lib.h" | ||
30 | #include "gnunet_child_management_lib.h" | ||
31 | |||
32 | |||
33 | /** | ||
34 | * Struct which defines a Child Wait handle | ||
35 | */ | ||
36 | struct GNUNET_ChildWaitHandle | ||
37 | { | ||
38 | /** | ||
39 | * Linked list to the next child | ||
40 | */ | ||
41 | struct GNUNET_ChildWaitHandle *next; | ||
42 | /** | ||
43 | * Linked list to the previous child | ||
44 | */ | ||
45 | struct GNUNET_ChildWaitHandle *prev; | ||
46 | /** | ||
47 | * Child process which is managed | ||
48 | */ | ||
49 | struct GNUNET_OS_Process *proc; | ||
50 | /** | ||
51 | * Callback which is called upon completion/death of the child task | ||
52 | */ | ||
53 | GNUNET_ChildCompletedCallback cb; | ||
54 | /** | ||
55 | * Closure for the handle | ||
56 | */ | ||
57 | void *cb_cls; | ||
58 | }; | ||
59 | |||
60 | |||
61 | /** | ||
62 | * Pipe used to communicate shutdown via signal. | ||
63 | */ | ||
64 | static struct GNUNET_DISK_PipeHandle *sigpipe; | ||
65 | |||
66 | static struct GNUNET_SIGNAL_Context *shc_chld; | ||
67 | |||
68 | static struct GNUNET_SCHEDULER_Task *sig_task; | ||
69 | |||
70 | static struct GNUNET_ChildWaitHandle *cwh_head; | ||
71 | |||
72 | static struct GNUNET_ChildWaitHandle *cwh_tail; | ||
73 | |||
74 | /** | ||
75 | * Task triggered whenever we receive a SIGCHLD (child | ||
76 | * process died) or when user presses CTRL-C. | ||
77 | * | ||
78 | * @param cls closure, NULL | ||
79 | */ | ||
80 | static void | ||
81 | maint_child_death (void *cls) | ||
82 | { | ||
83 | char buf[16]; | ||
84 | const struct GNUNET_DISK_FileHandle *pr; | ||
85 | struct GNUNET_ChildWaitHandle *nxt; | ||
86 | |||
87 | (void) cls; | ||
88 | sig_task = NULL; | ||
89 | /* drain pipe */ | ||
90 | pr = GNUNET_DISK_pipe_handle (sigpipe, | ||
91 | GNUNET_DISK_PIPE_END_READ); | ||
92 | GNUNET_assert (! GNUNET_DISK_handle_invalid (pr)); | ||
93 | |||
94 | (void) GNUNET_DISK_file_read (pr, | ||
95 | buf, | ||
96 | sizeof(buf)); | ||
97 | |||
98 | /* find applicable processes that exited */ | ||
99 | for (struct GNUNET_ChildWaitHandle *cwh = cwh_head; | ||
100 | NULL != cwh; | ||
101 | cwh = nxt) | ||
102 | { | ||
103 | enum GNUNET_OS_ProcessStatusType type; | ||
104 | long unsigned int exit_code = 0; | ||
105 | |||
106 | nxt = cwh->next; | ||
107 | if (GNUNET_OK == | ||
108 | GNUNET_OS_process_status (cwh->proc, | ||
109 | &type, | ||
110 | &exit_code)) | ||
111 | { | ||
112 | GNUNET_CONTAINER_DLL_remove (cwh_head, | ||
113 | cwh_tail, | ||
114 | cwh); | ||
115 | cwh->cb (cwh->cb_cls, | ||
116 | type, | ||
117 | exit_code); | ||
118 | GNUNET_free (cwh); | ||
119 | } | ||
120 | } | ||
121 | if (NULL == cwh_head) | ||
122 | return; | ||
123 | /* wait for more */ | ||
124 | sig_task = GNUNET_SCHEDULER_add_read_file ( | ||
125 | GNUNET_TIME_UNIT_FOREVER_REL, | ||
126 | GNUNET_DISK_pipe_handle (sigpipe, | ||
127 | GNUNET_DISK_PIPE_END_READ), | ||
128 | &maint_child_death, | ||
129 | NULL); | ||
130 | } | ||
131 | |||
132 | |||
133 | /** | ||
134 | * Signal handler called for SIGCHLD. Triggers the | ||
135 | * respective handler by writing to the trigger pipe. | ||
136 | */ | ||
137 | static void | ||
138 | sighandler_child_death (void) | ||
139 | { | ||
140 | static char c; | ||
141 | int old_errno = errno; /* back-up errno */ | ||
142 | |||
143 | GNUNET_break ( | ||
144 | 1 == | ||
145 | GNUNET_DISK_file_write (GNUNET_DISK_pipe_handle (sigpipe, | ||
146 | GNUNET_DISK_PIPE_END_WRITE), | ||
147 | &c, | ||
148 | sizeof(c))); | ||
149 | errno = old_errno; /* restore errno */ | ||
150 | } | ||
151 | |||
152 | |||
153 | void __attribute__ ((constructor)) | ||
154 | child_management_start () | ||
155 | { | ||
156 | if (NULL != sigpipe) | ||
157 | return; /* already initialized */ | ||
158 | sigpipe = GNUNET_DISK_pipe (GNUNET_DISK_PF_NONE); | ||
159 | GNUNET_assert (sigpipe != NULL); | ||
160 | shc_chld = | ||
161 | GNUNET_SIGNAL_handler_install (GNUNET_SIGCHLD, &sighandler_child_death); | ||
162 | } | ||
163 | |||
164 | |||
165 | struct GNUNET_ChildWaitHandle * | ||
166 | GNUNET_wait_child (struct GNUNET_OS_Process *proc, | ||
167 | GNUNET_ChildCompletedCallback cb, | ||
168 | void *cb_cls) | ||
169 | { | ||
170 | struct GNUNET_ChildWaitHandle *cwh; | ||
171 | |||
172 | child_management_start (); | ||
173 | cwh = GNUNET_new (struct GNUNET_ChildWaitHandle); | ||
174 | cwh->proc = proc; | ||
175 | cwh->cb = cb; | ||
176 | cwh->cb_cls = cb_cls; | ||
177 | GNUNET_CONTAINER_DLL_insert (cwh_head, | ||
178 | cwh_tail, | ||
179 | cwh); | ||
180 | if (NULL == sig_task) | ||
181 | { | ||
182 | sig_task = GNUNET_SCHEDULER_add_read_file ( | ||
183 | GNUNET_TIME_UNIT_FOREVER_REL, | ||
184 | GNUNET_DISK_pipe_handle (sigpipe, | ||
185 | GNUNET_DISK_PIPE_END_READ), | ||
186 | &maint_child_death, | ||
187 | NULL); | ||
188 | } | ||
189 | return cwh; | ||
190 | } | ||
191 | |||
192 | |||
193 | void | ||
194 | GNUNET_wait_child_cancel (struct GNUNET_ChildWaitHandle *cwh) | ||
195 | { | ||
196 | GNUNET_CONTAINER_DLL_remove (cwh_head, | ||
197 | cwh_tail, | ||
198 | cwh); | ||
199 | if (NULL == cwh_head) | ||
200 | { | ||
201 | GNUNET_SCHEDULER_cancel (sig_task); | ||
202 | sig_task = NULL; | ||
203 | } | ||
204 | GNUNET_free (cwh); | ||
205 | } | ||
206 | |||
207 | |||
208 | /** | ||
209 | * Clean up. | ||
210 | */ | ||
211 | void __attribute__ ((destructor)) | ||
212 | GNUNET_CM_done () | ||
213 | { | ||
214 | GNUNET_assert (NULL == sig_task); | ||
215 | GNUNET_SIGNAL_handler_uninstall (shc_chld); | ||
216 | shc_chld = NULL; | ||
217 | GNUNET_DISK_pipe_close (sigpipe); | ||
218 | sigpipe = NULL; | ||
219 | } | ||