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// Fork.C -*- C++ -*- socket library |
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// Copyright (C) 1992,1993,1994 Gnanasekaran Swaminathan <gs4t@virginia.edu> |
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// |
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// Permission is granted to use at your own risk and distribute this software |
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// in source and binary forms provided the above copyright |
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// notice and this paragraph are preserved on all copies. |
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// This software is provided "as is" with no express or implied warranty. |
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// |
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// Version: 17Oct95 1.10 |
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|
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#include <config.h> |
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|
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#include <iostream.h> |
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#include <stdio.h> // perror in solaris2.3 is declared here |
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#include <stdlib.h> |
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#include <unistd.h> |
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#include <errno.h> |
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#include <signal.h> |
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#include <sys/wait.h> |
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|
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#include <Fork.h> |
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|
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Fork::ForkProcess* Fork::ForkProcess::list = 0; |
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Fork::KillForks Fork::killall; |
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|
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Fork::~Fork () |
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{ |
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if (process->pid <= 0) |
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delete process; |
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} |
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|
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Fork::KillForks::~KillForks () |
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// First, kill all children whose kill_child flag is set. |
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// Second, wait for other children to die. |
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{ |
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for (ForkProcess* cur = Fork::ForkProcess::list; cur; cur = cur->next) |
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if (cur->kill_child) |
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delete cur; |
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|
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while (Fork::ForkProcess::list && wait (0) > 0); |
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} |
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|
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Fork::ForkProcess::ForkProcess (int kill, int give_reason) |
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: kill_child (kill), reason (give_reason), next (0) |
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{ |
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if (list == 0) { |
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struct sigaction sa; |
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sa.sa_handler = funcptr (&Fork::ForkProcess::reaper_nohang); |
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sigemptyset (&sa.sa_mask); |
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sa.sa_flags = SA_RESTART; |
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sigaction (SIGCHLD, &sa, 0); |
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} |
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|
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pid = fork (); |
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|
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if (pid > 0) { |
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next = list; |
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list = this; |
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} else if (pid == 0) { |
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// child process. clear list |
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ForkProcess* p = list; |
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while (p) { |
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ForkProcess* nxt = p->next; |
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p->pid = 0; |
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delete p; |
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p = nxt; |
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} |
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list = 0; |
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|
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if (kill_child) { |
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struct sigaction sa; |
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sa.sa_handler = funcptr (&Fork::ForkProcess::commit_suicide); |
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sigemptyset (&sa.sa_mask); |
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sa.sa_flags = SA_RESTART; |
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sigaction (SIGTERM, &sa, 0); |
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} |
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} |
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} |
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|
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Fork::ForkProcess::~ForkProcess () |
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{ |
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if (pid > 0) { |
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if (kill_child) |
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kill (pid, SIGTERM); |
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reap_child (); |
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|
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// I remove myself from list |
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if (list == this) |
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list = list->next; |
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else { |
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for (ForkProcess* p = list; p; p = p->next) |
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if (p->next == this) { |
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p->next = next; |
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break; |
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} |
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} |
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} |
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} |
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|
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void Fork::ForkProcess::kill_process () const |
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{ |
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if (pid > 0) { |
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kill (pid, SIGKILL); |
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reap_child (); |
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} |
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} |
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|
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void Fork::ForkProcess::reap_child () const |
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{ |
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int status; |
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if (pid > 0 && waitpid (pid, &status, 0) == pid && reason) |
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infanticide_reason (pid, status); |
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} |
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|
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void Fork::ForkProcess::infanticide_reason (pid_t pid, int status) |
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{ |
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if (pid <= 0) |
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return; |
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|
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if (WIFSTOPPED (status)) |
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cerr << "process " << pid << " gets " |
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<< SYS_SIGLIST [WSTOPSIG (status)] << endl; |
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else if (WIFEXITED (status)) |
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cerr << "process " << pid << " exited with status " |
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<< WEXITSTATUS (status) << endl; |
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else if (WIFSIGNALED (status)) |
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cerr << "process " << pid << " got " |
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<< SYS_SIGLIST [WTERMSIG (status)] << endl; |
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} |
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|
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void Fork::ForkProcess::reaper_nohang (int signo) |
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{ |
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if (signo != SIGCHLD) |
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return; |
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|
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int status; |
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pid_t wpid; |
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if ((wpid = waitpid (-1, &status, WNOHANG)) > 0) { |
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ForkProcess* prev = 0; |
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ForkProcess* cur = list; |
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while (cur) { |
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if (cur->pid == wpid) { |
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cur->pid = -1; |
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if (prev) |
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prev->next = cur->next; |
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else |
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list = list->next; |
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|
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if (cur->reason) |
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infanticide_reason (wpid, status); |
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|
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delete cur; |
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break; |
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} |
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prev = cur; |
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cur = cur->next; |
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} |
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} |
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} |
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|
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void Fork::ForkProcess::commit_suicide (int) |
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{ |
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// if this process has any children we kill them. |
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|
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ForkProcess* p = list; |
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while (p) { |
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ForkProcess* next = p->next; |
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if (!p->kill_child) // otherwise ForkProcess::~ForkProcess will take care |
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kill (p->pid, SIGKILL); |
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delete p; // ForkProcess::~ForkProcess will call reap_child (). |
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p = next; |
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} |
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|
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exit (0x0f); |
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} |
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|
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void Fork::suicide_signal (int signo) |
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// commit suicide at the signal signo |
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{ |
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struct sigaction sa; |
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sa.sa_handler = funcptr (&Fork::ForkProcess::commit_suicide); |
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sigemptyset (&sa.sa_mask); |
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sa.sa_flags = 0; |
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if (sigaction (signo, &sa, 0) == -1) |
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perror ("Fork: Cannot commit suicide with the specified signal"); |
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} |
