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// Fork.C -*- C++ -*- socket library
// Copyright (C) 1992-1996 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: 12Jan97 1.11
#ifndef WIN32
#include <config.h>
#include <iostream>
#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 <socket++/fork.h>
using std::cerr;
using std::endl;
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 (bool kill, bool give_reason)
: kill_child (kill), reason (give_reason), next (0)
{
if (list == 0) {
struct sigaction sa;
sa.sa_handler = (void(*)(int)) sighnd (&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 = (void(*)(int)) sighnd (&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;
#ifdef SOCKETXX_HAVE_STRSIGNAL
if (WIFSTOPPED (status))
cerr << "process " << pid << " gets "
<< strsignal(WSTOPSIG (status)) << endl;
else if (WIFEXITED (status))
cerr << "process " << pid << " exited with status "
<< WEXITSTATUS (status) << endl;
else if (WIFSIGNALED (status))
cerr << "process " << pid << " got "
<< strsignal(WTERMSIG (status)) << endl;
#else
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;
#endif // SOCKETXX_HAVE_STRSIGNAL
}
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 = (void(*)(int)) sighnd (&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");
}
#endif //windows does not get fork
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