c%2B%2B/socket%2B%2B-1.10/Fork.C

// Fork.C -*- C++ -*- socket library
// Copyright (C) 1992,1993,1994 Gnanasekaran Swaminathan <gs4t@virginia.edu>
// 
// Permission is granted to use at your own risk and distribute this software
// in source and binary forms provided the above copyright
// notice and this paragraph are preserved on all copies.
// This software is provided "as is" with no express or implied warranty.
//
// Version: 17Oct95 1.10

#include <config.h>

#include <iostream.h>
#include <stdio.h> // perror in solaris2.3 is declared here
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/wait.h>

#include <Fork.h>

Fork::ForkProcess* Fork::ForkProcess::list = 0;
Fork::KillForks Fork::killall;

Fork::~Fork ()
{
  if (process->pid <= 0)
    delete process;
}

Fork::KillForks::~KillForks ()
     // First, kill all children whose kill_child flag is set.
     // Second, wait for other children to die.
{
  for (ForkProcess* cur = Fork::ForkProcess::list; cur; cur = cur->next)
    if (cur->kill_child)
      delete cur;

  while (Fork::ForkProcess::list && wait (0) > 0);
}

Fork::ForkProcess::ForkProcess (int kill, int give_reason)
     : kill_child (kill), reason (give_reason), next (0)
{
  if (list == 0) {
    struct sigaction sa;
    sa.sa_handler = funcptr (&Fork::ForkProcess::reaper_nohang);
    sigemptyset (&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    sigaction (SIGCHLD, &sa, 0);
  }

  pid = fork ();

  if (pid > 0) {
    next = list;
    list = this;
  } else if (pid == 0) {
    // child process. clear list
    ForkProcess* p = list;
    while (p) {
      ForkProcess* nxt = p->next;
      p->pid = 0;
      delete p;
      p = nxt;
    }
    list = 0;

    if (kill_child) {
      struct sigaction sa;
      sa.sa_handler = funcptr (&Fork::ForkProcess::commit_suicide);
      sigemptyset (&sa.sa_mask);
      sa.sa_flags = SA_RESTART;
      sigaction (SIGTERM, &sa, 0);
    }
  }
}

Fork::ForkProcess::~ForkProcess ()
{
  if (pid > 0) {
    if (kill_child)
      kill (pid, SIGTERM);
    reap_child ();

    // I remove myself from list
    if (list == this)
      list = list->next;
    else {
      for (ForkProcess* p = list; p; p = p->next)
        if (p->next == this) {
          p->next = next;
          break;
        }
    }
  }
}

void Fork::ForkProcess::kill_process () const
{
  if (pid > 0) {
    kill (pid, SIGKILL);
    reap_child ();
  }
}

void Fork::ForkProcess::reap_child () const
{
  int status;
  if (pid > 0 && waitpid (pid, &status, 0) == pid && reason)
    infanticide_reason (pid, status);
}

void Fork::ForkProcess::infanticide_reason (pid_t pid, int status)
{
  if (pid <= 0)
    return;

  if (WIFSTOPPED (status))
    cerr << "process " << pid << " gets "
      << SYS_SIGLIST [WSTOPSIG (status)] << endl;
  else if (WIFEXITED (status))
    cerr << "process " << pid << " exited with status "
      << WEXITSTATUS (status) << endl;
  else if (WIFSIGNALED (status))
    cerr << "process " << pid << " got "
      << SYS_SIGLIST [WTERMSIG (status)] << endl;
}

void Fork::ForkProcess::reaper_nohang (int signo)
{
  if (signo != SIGCHLD)
    return;

  int status;
  pid_t wpid;
  if ((wpid = waitpid (-1, &status, WNOHANG)) > 0) {
    ForkProcess* prev = 0;
    ForkProcess* cur  = list;
    while (cur) {
      if (cur->pid == wpid) {
        cur->pid = -1;
        if (prev)
          prev->next = cur->next;
        else
          list = list->next;
        
        if (cur->reason)
          infanticide_reason (wpid, status);

        delete cur;
        break;
      }
      prev = cur;
      cur  = cur->next;
    }
  }
}

void Fork::ForkProcess::commit_suicide (int)
{
  // if this process has any children we kill them.

  ForkProcess* p = list;
  while (p) {
    ForkProcess* next = p->next;
    if (!p->kill_child) // otherwise ForkProcess::~ForkProcess will take care
      kill (p->pid, SIGKILL);
    delete p; // ForkProcess::~ForkProcess will call reap_child ().
    p = next;
  }

  exit (0x0f); 
}

void Fork::suicide_signal (int signo)
     // commit suicide at the signal signo
{
  struct sigaction sa;
  sa.sa_handler = funcptr (&Fork::ForkProcess::commit_suicide);
  sigemptyset (&sa.sa_mask);
  sa.sa_flags = 0;
  if (sigaction (signo, &sa, 0) == -1)
    perror ("Fork: Cannot commit suicide with the specified signal");
}
Revision:	1.2
Committed:	Mon Jun 10 14:10:43 2002 UTC (22 years, 4 months ago) by tdb
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.1:	+0 -0 lines
State:	*FILE REMOVED*
Error occurred while calculating annotation data.
Log Message:	Tidy up of files. These are all old things that are not only no longer used but are also probably useless to anyone other than us. This saves checking them out all the time, and makes the "cms/source" tree contain only current stuff. They'll still exist in the attic's though :)
#	Content
1	// Fork.C -- C++ -- socket library
2	// Copyright (C) 1992,1993,1994 Gnanasekaran Swaminathan <gs4t@virginia.edu>
3	//
4	// Permission is granted to use at your own risk and distribute this software
5	// in source and binary forms provided the above copyright
6	// notice and this paragraph are preserved on all copies.
7	// This software is provided "as is" with no express or implied warranty.
8	//
9	// Version: 17Oct95 1.10
10
11	#include <config.h>
12
13	#include <iostream.h>
14	#include <stdio.h> // perror in solaris2.3 is declared here
15	#include <stdlib.h>
16	#include <unistd.h>
17	#include <errno.h>
18	#include <signal.h>
19	#include <sys/wait.h>
20
21	#include <Fork.h>
22
23	Fork::ForkProcess* Fork::ForkProcess::list = 0;
24	Fork::KillForks Fork::killall;
25
26	Fork::~Fork ()
27	{
28	if (process->pid <= 0)
29	delete process;
30	}
31
32	Fork::KillForks::~KillForks ()
33	// First, kill all children whose kill_child flag is set.
34	// Second, wait for other children to die.
35	{
36	for (ForkProcess* cur = Fork::ForkProcess::list; cur; cur = cur->next)
37	if (cur->kill_child)
38	delete cur;
39
40	while (Fork::ForkProcess::list && wait (0) > 0);
41	}
42
43	Fork::ForkProcess::ForkProcess (int kill, int give_reason)
44	: kill_child (kill), reason (give_reason), next (0)
45	{
46	if (list == 0) {
47	struct sigaction sa;
48	sa.sa_handler = funcptr (&Fork::ForkProcess::reaper_nohang);
49	sigemptyset (&sa.sa_mask);
50	sa.sa_flags = SA_RESTART;
51	sigaction (SIGCHLD, &sa, 0);
52	}
53
54	pid = fork ();
55
56	if (pid > 0) {
57	next = list;
58	list = this;
59	} else if (pid == 0) {
60	// child process. clear list
61	ForkProcess* p = list;
62	while (p) {
63	ForkProcess* nxt = p->next;
64	p->pid = 0;
65	delete p;
66	p = nxt;
67	}
68	list = 0;
69
70	if (kill_child) {
71	struct sigaction sa;
72	sa.sa_handler = funcptr (&Fork::ForkProcess::commit_suicide);
73	sigemptyset (&sa.sa_mask);
74	sa.sa_flags = SA_RESTART;
75	sigaction (SIGTERM, &sa, 0);
76	}
77	}
78	}
79
80	Fork::ForkProcess::~ForkProcess ()
81	{
82	if (pid > 0) {
83	if (kill_child)
84	kill (pid, SIGTERM);
85	reap_child ();
86
87	// I remove myself from list
88	if (list == this)
89	list = list->next;
90	else {
91	for (ForkProcess* p = list; p; p = p->next)
92	if (p->next == this) {
93	p->next = next;
94	break;
95	}
96	}
97	}
98	}
99
100	void Fork::ForkProcess::kill_process () const
101	{
102	if (pid > 0) {
103	kill (pid, SIGKILL);
104	reap_child ();
105	}
106	}
107
108	void Fork::ForkProcess::reap_child () const
109	{
110	int status;
111	if (pid > 0 && waitpid (pid, &status, 0) == pid && reason)
112	infanticide_reason (pid, status);
113	}
114
115	void Fork::ForkProcess::infanticide_reason (pid_t pid, int status)
116	{
117	if (pid <= 0)
118	return;
119
120	if (WIFSTOPPED (status))
121	cerr << "process " << pid << " gets "
122	<< SYS_SIGLIST [WSTOPSIG (status)] << endl;
123	else if (WIFEXITED (status))
124	cerr << "process " << pid << " exited with status "
125	<< WEXITSTATUS (status) << endl;
126	else if (WIFSIGNALED (status))
127	cerr << "process " << pid << " got "
128	<< SYS_SIGLIST [WTERMSIG (status)] << endl;
129	}
130
131	void Fork::ForkProcess::reaper_nohang (int signo)
132	{
133	if (signo != SIGCHLD)
134	return;
135
136	int status;
137	pid_t wpid;
138	if ((wpid = waitpid (-1, &status, WNOHANG)) > 0) {
139	ForkProcess* prev = 0;
140	ForkProcess* cur = list;
141	while (cur) {
142	if (cur->pid == wpid) {
143	cur->pid = -1;
144	if (prev)
145	prev->next = cur->next;
146	else
147	list = list->next;
148
149	if (cur->reason)
150	infanticide_reason (wpid, status);
151
152	delete cur;
153	break;
154	}
155	prev = cur;
156	cur = cur->next;
157	}
158	}
159	}
160
161	void Fork::ForkProcess::commit_suicide (int)
162	{
163	// if this process has any children we kill them.
164
165	ForkProcess* p = list;
166	while (p) {
167	ForkProcess* next = p->next;
168	if (!p->kill_child) // otherwise ForkProcess::~ForkProcess will take care
169	kill (p->pid, SIGKILL);
170	delete p; // ForkProcess::~ForkProcess will call reap_child ().
171	p = next;
172	}
173
174	exit (0x0f);
175	}
176
177	void Fork::suicide_signal (int signo)
178	// commit suicide at the signal signo
179	{
180	struct sigaction sa;
181	sa.sa_handler = funcptr (&Fork::ForkProcess::commit_suicide);
182	sigemptyset (&sa.sa_mask);
183	sa.sa_flags = 0;
184	if (sigaction (signo, &sa, 0) == -1)
185	perror ("Fork: Cannot commit suicide with the specified signal");
186	}