GNUnet  0.11.x
child_management.c
Go to the documentation of this file.
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 
28 #include "platform.h"
29 #include "gnunet_util_lib.h"
31 
32 
37 {
57  void *cb_cls;
58 };
59 
60 
65 
67 
69 
71 
73 
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,
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  {
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 (
126  GNUNET_DISK_pipe_handle (sigpipe,
129  NULL);
130 }
131 
132 
137 static void
139 {
140  static char c;
141  int old_errno = errno; /* back-up errno */
142 
143  GNUNET_break (
144  1 ==
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 */
159  GNUNET_assert (sigpipe != NULL);
160  shc_chld =
162 }
163 
164 
165 struct GNUNET_ChildWaitHandle *
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 (
184  GNUNET_DISK_pipe_handle (sigpipe,
187  NULL);
188  }
189  return cwh;
190 }
191 
192 
193 void
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 
211 void __attribute__ ((destructor))
212 GNUNET_CM_done ()
213 {
214  GNUNET_assert (NULL == sig_task);
216  shc_chld = NULL;
217  GNUNET_DISK_pipe_close (sigpipe);
218  sigpipe = NULL;
219 }
static struct GNUNET_SIGNAL_Context * shc_chld
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
No special options, use non-blocking read/write operations.
struct GNUNET_ChildWaitHandle * GNUNET_wait_child(struct GNUNET_OS_Process *proc, GNUNET_ChildCompletedCallback cb, void *cb_cls)
Starts the handling of the child processes.
#define GNUNET_CONTAINER_DLL_insert(head, tail, element)
Insert an element at the head of a DLL.
static struct GNUNET_DISK_PipeHandle * sigpipe
Pipe used to communicate shutdown via signal.
#define GNUNET_SIGCHLD
Definition: platform.h:42
ssize_t GNUNET_DISK_file_read(const struct GNUNET_DISK_FileHandle *h, void *result, size_t len)
Read the contents of a binary file into a buffer.
Definition: disk.c:602
int GNUNET_OS_process_status(struct GNUNET_OS_Process *proc, enum GNUNET_OS_ProcessStatusType *type, unsigned long *code)
Retrieve the status of a process.
Definition: os_priority.c:946
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_read_file(struct GNUNET_TIME_Relative delay, const struct GNUNET_DISK_FileHandle *rfd, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay or when the specified file descriptor is ready f...
Definition: scheduler.c:1667
void GNUNET_SIGNAL_handler_uninstall(struct GNUNET_SIGNAL_Context *ctx)
Uninstall a previously installed signal handler.
Definition: signal.c:77
#define GNUNET_new(type)
Allocate a struct or union of the given type.
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur...
const struct GNUNET_DISK_FileHandle * GNUNET_DISK_pipe_handle(const struct GNUNET_DISK_PipeHandle *p, enum GNUNET_DISK_PipeEnd n)
Get the handle to a particular pipe end.
Definition: disk.c:1436
static void sighandler_child_death(void)
Signal handler called for SIGCHLD.
struct GNUNET_OS_Process * proc
Child process which is managed.
void * cb_cls
Closure for the handle.
enum GNUNET_GenericReturnValue GNUNET_DISK_pipe_close(struct GNUNET_DISK_PipeHandle *p)
Closes an interprocess channel.
Definition: disk.c:1405
ssize_t GNUNET_DISK_file_write(const struct GNUNET_DISK_FileHandle *h, const void *buffer, size_t n)
Write a buffer to a file.
Definition: disk.c:666
GNUNET_OS_ProcessStatusType
Process status types.
static char buf[2048]
#define GNUNET_TIME_UNIT_FOREVER_REL
Constant used to specify "forever".
The writing-end of a pipe.
The reading-end of a pipe.
static void maint_child_death(void *cls)
Task triggered whenever we receive a SIGCHLD (child process died) or when user presses CTRL-C...
struct GNUNET_DISK_PipeHandle * GNUNET_DISK_pipe(enum GNUNET_DISK_PipeFlags pf)
Creates an interprocess channel.
Definition: disk.c:1262
struct GNUNET_ChildWaitHandle * next
Linked list to the next child.
struct GNUNET_SIGNAL_Context * GNUNET_SIGNAL_handler_install(int signal, GNUNET_SIGNAL_Handler handler)
Install a signal handler that will be run if the given signal is received.
Definition: signal.c:51
GNUNET_ChildCompletedCallback cb
Callback which is called upon completion/death of the child task.
static struct GNUNET_ChildWaitHandle * cwh_tail
void __attribute__((constructor))
void(* GNUNET_ChildCompletedCallback)(void *cls, enum GNUNET_OS_ProcessStatusType type, long unsigned int exit_code)
Defines a GNUNET_ChildCompletedCallback which is sent back upon death or completion of a child proces...
enum GNUNET_GenericReturnValue GNUNET_DISK_handle_invalid(const struct GNUNET_DISK_FileHandle *h)
Checks whether a handle is invalid.
Definition: disk.c:186
GNUnet child management api.
static struct GNUNET_ChildWaitHandle * cwh_head
Entry in list of pending tasks.
Definition: scheduler.c:134
static struct GNUNET_SCHEDULER_Task * sig_task
Struct which defines a Child Wait handle.
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model
struct GNUNET_ChildWaitHandle * prev
Linked list to the previous child.
void GNUNET_wait_child_cancel(struct GNUNET_ChildWaitHandle *cwh)
Stop waiting on this child.
Handle used to access files (and pipes).
Handle used to manage a pipe.
Definition: disk.c:68
#define GNUNET_free(ptr)
Wrapper around free.
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:972
static long unsigned int exit_code
Handler exit code.
Definition: gnunet-qr.c:54