mistserver/lib/procs.cpp

670 lines
18 KiB
C++

/// \file procs.cpp
/// Contains generic functions for managing processes.
#include "procs.h"
#include <string.h>
#include <sys/types.h>
#include <signal.h>
#if defined(__FreeBSD__) || defined(__APPLE__) || defined(__MACH__)
#include <sys/wait.h>
#else
#include <wait.h>
#endif
#include <errno.h>
#include <iostream>
#include <sys/types.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdlib.h>
#include <stdio.h>
#include "timing.h"
std::map<pid_t, std::string> Util::Procs::plist;
std::map<pid_t, Util::TerminationNotifier> Util::Procs::exitHandlers;
bool Util::Procs::handler_set = false;
/// Called at exit of any program that used a Start* function.
/// Waits up to 2.5 seconds, then sends SIGINT signal to all managed processes.
/// After that waits up to 10 seconds for children to exit, then sends SIGKILL to
/// all remaining children. Waits one more second for cleanup to finish, then exits.
void Util::Procs::exit_handler(){
int waiting = 0;
while ( !plist.empty()){
Util::sleep(100);
if (++waiting > 25){
break;
}
}
if ( !plist.empty()){
std::map<pid_t, std::string> listcopy = plist;
std::map<pid_t, std::string>::iterator it;
for (it = listcopy.begin(); it != listcopy.end(); it++){
kill(( *it).first, SIGINT);
}
}
waiting = 0;
while ( !plist.empty()){
Util::sleep(200);
if (++waiting > 25){
break;
}
}
if ( !plist.empty()){
std::map<pid_t, std::string> listcopy = plist;
std::map<pid_t, std::string>::iterator it;
for (it = listcopy.begin(); it != listcopy.end(); it++){
kill(( *it).first, SIGKILL);
}
}
waiting = 0;
while ( !plist.empty()){
Util::sleep(100);
if (++waiting > 10){
break;
}
}
}
/// Sets up exit and childsig handlers.
/// Called by every Start* function.
void Util::Procs::setHandler(){
if ( !handler_set){
struct sigaction new_action;
new_action.sa_handler = childsig_handler;
sigemptyset( &new_action.sa_mask);
new_action.sa_flags = 0;
sigaction(SIGCHLD, &new_action, NULL);
atexit(exit_handler);
handler_set = true;
}
}
/// Used internally to capture child signals and update plist.
void Util::Procs::childsig_handler(int signum){
if (signum != SIGCHLD){
return;
}
int status;
pid_t ret = waitpid( -1, &status, WNOHANG);
if (ret == 0){ //ignore, would block otherwise
return;
}else if (ret < 0){
if (errno == EINTR){
childsig_handler(signum);
return;
}
#if DEBUG >= 3
std::cerr << "SIGCHLD received, but no child died";
#endif
return;
}
int exitcode;
if (WIFEXITED(status)){
exitcode = WEXITSTATUS(status);
}else if (WIFSIGNALED(status)){
exitcode = -WTERMSIG(status);
}else{/* not possible */
return;
}
#if DEBUG >= 1
std::string pname = plist[ret];
#endif
plist.erase(ret);
#if DEBUG >= 1
if (isActive(pname)){
Stop(pname);
} else{
//can this ever happen?
std::cerr << "Process " << pname << " fully terminated." << std::endl;
}
#endif
if (exitHandlers.count(ret) > 0){
TerminationNotifier tn = exitHandlers[ret];
exitHandlers.erase(ret);
#if DEBUG >= 2
std::cerr << "Calling termination handler for " << pname << std::endl;
#endif
tn(ret, exitcode);
}
}
/// Attempts to run the command cmd.
/// Replaces the current process - use after forking first!
/// This function will never return - it will either run the given
/// command or kill itself with return code 42.
void Util::Procs::runCmd(std::string & cmd){
//split cmd into arguments
//supports a maximum of 20 arguments
char * tmp = (char*)cmd.c_str();
char * tmp2 = 0;
char * args[21];
int i = 0;
tmp2 = strtok(tmp, " ");
args[0] = tmp2;
while (tmp2 != 0 && (i < 20)){
tmp2 = strtok(0, " ");
++i;
args[i] = tmp2;
}
if (i == 20){
args[20] = 0;
}
//execute the command
execvp(args[0], args);
#if DEBUG >= 1
std::cerr << "Error running \"" << cmd << "\": " << strerror(errno) << std::endl;
#endif
_exit(42);
}
/// Starts a new process if the name is not already active.
/// \return 0 if process was not started, process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Commandline for this process.
pid_t Util::Procs::Start(std::string name, std::string cmd){
if (isActive(name)){
return getPid(name);
}
setHandler();
pid_t ret = fork();
if (ret == 0){
runCmd(cmd);
}else{
if (ret > 0){
#if DEBUG >= 1
std::cerr << "Process " << name << " started, PID " << ret << ": " << cmd << std::endl;
#endif
plist.insert(std::pair<pid_t, std::string>(ret, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
return 0;
}
}
return ret;
}
/// Starts two piped processes if the name is not already active.
/// \return 0 if process was not started, sub (sending) process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Commandline for sub (sending) process.
/// \arg cmd2 Commandline for main (receiving) process.
pid_t Util::Procs::Start(std::string name, std::string cmd, std::string cmd2){
if (isActive(name)){
return getPid(name);
}
setHandler();
int pfildes[2];
if (pipe(pfildes) == -1){
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. Pipe creation failed." << std::endl;
#endif
return 0;
}
int devnull = open("/dev/null", O_RDWR);
pid_t ret = fork();
if (ret == 0){
close(pfildes[0]);
dup2(pfildes[1], STDOUT_FILENO);
close(pfildes[1]);
dup2(devnull, STDIN_FILENO);
dup2(devnull, STDERR_FILENO);
runCmd(cmd);
}else{
if (ret > 0){
plist.insert(std::pair<pid_t, std::string>(ret, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
close(pfildes[1]);
close(pfildes[0]);
return 0;
}
}
pid_t ret2 = fork();
if (ret2 == 0){
close(pfildes[1]);
dup2(pfildes[0], STDIN_FILENO);
close(pfildes[0]);
dup2(devnull, STDOUT_FILENO);
dup2(devnull, STDERR_FILENO);
runCmd(cmd2);
}else{
if (ret2 > 0){
#if DEBUG >= 1
std::cerr << "Process " << name << " started, PIDs (" << ret << ", " << ret2 << "): " << cmd << " | " << cmd2 << std::endl;
#endif
plist.insert(std::pair<pid_t, std::string>(ret2, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
Stop(name);
close(pfildes[1]);
close(pfildes[0]);
return 0;
}
}
close(pfildes[1]);
close(pfildes[0]);
return ret;
}
/// Starts three piped processes if the name is not already active.
/// \return 0 if process was not started, sub (sending) process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Commandline for sub (sending) process.
/// \arg cmd2 Commandline for sub (middle) process.
/// \arg cmd3 Commandline for main (receiving) process.
pid_t Util::Procs::Start(std::string name, std::string cmd, std::string cmd2, std::string cmd3){
if (isActive(name)){
return getPid(name);
}
setHandler();
int pfildes[2];
int pfildes2[2];
if (pipe(pfildes) == -1){
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. Pipe creation failed." << std::endl;
#endif
return 0;
}
if (pipe(pfildes2) == -1){
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. Pipe creation failed." << std::endl;
#endif
return 0;
}
int devnull = open("/dev/null", O_RDWR);
pid_t ret = fork();
if (ret == 0){
close(pfildes[0]);
dup2(pfildes[1], STDOUT_FILENO);
close(pfildes[1]);
dup2(devnull, STDIN_FILENO);
dup2(devnull, STDERR_FILENO);
close(pfildes2[1]);
close(pfildes2[0]);
runCmd(cmd);
}else{
if (ret > 0){
plist.insert(std::pair<pid_t, std::string>(ret, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
close(pfildes[1]);
close(pfildes[0]);
close(pfildes2[1]);
close(pfildes2[0]);
return 0;
}
}
pid_t ret2 = fork();
if (ret2 == 0){
close(pfildes[1]);
close(pfildes2[0]);
dup2(pfildes[0], STDIN_FILENO);
close(pfildes[0]);
dup2(pfildes2[1], STDOUT_FILENO);
close(pfildes2[1]);
dup2(devnull, STDERR_FILENO);
runCmd(cmd2);
}else{
if (ret2 > 0){
#if DEBUG >= 1
std::cerr << "Process " << name << " started, PIDs (" << ret << ", " << ret2 << "): " << cmd << " | " << cmd2 << std::endl;
#endif
plist.insert(std::pair<pid_t, std::string>(ret2, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
Stop(name);
close(pfildes[1]);
close(pfildes[0]);
close(pfildes2[1]);
close(pfildes2[0]);
return 0;
}
}
close(pfildes[1]);
close(pfildes[0]);
pid_t ret3 = fork();
if (ret3 == 0){
close(pfildes[1]);
close(pfildes[0]);
close(pfildes2[1]);
dup2(pfildes2[0], STDIN_FILENO);
close(pfildes2[0]);
dup2(devnull, STDOUT_FILENO);
dup2(devnull, STDERR_FILENO);
runCmd(cmd3);
}else{
if (ret3 > 0){
#if DEBUG >= 1
std::cerr << "Process " << name << " started, PIDs (" << ret << ", " << ret2 << ", " << ret3 << "): " << cmd << " | " << cmd2 << " | " << cmd3 << std::endl;
#endif
plist.insert(std::pair<pid_t, std::string>(ret3, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
Stop(name);
close(pfildes[1]);
close(pfildes[0]);
close(pfildes2[1]);
close(pfildes2[0]);
return 0;
}
}
return ret3;
}
/// Starts a new process with given fds if the name is not already active.
/// \return 0 if process was not started, process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg argv Command for this process.
/// \arg fdin Standard input file descriptor. If null, /dev/null is assumed. Otherwise, if arg contains -1, a new fd is automatically allocated and written into this arg. Then the arg will be used as fd.
/// \arg fdout Same as fdin, but for stdout.
/// \arg fdout Same as fdin, but for stderr.
pid_t Util::Procs::StartPiped(std::string name, char * argv[], int * fdin, int * fdout, int * fderr){
if (isActive(name)){
return getPid(name);
}
pid_t pid;
int pipein[2], pipeout[2], pipeerr[2];
setHandler();
if (fdin && *fdin == -1 && pipe(pipein) < 0){
#if DEBUG >= 1
std::cerr << "Pipe (in) creation failed for " << name << std::endl;
#endif
return 0;
}
if (fdout && *fdout == -1 && pipe(pipeout) < 0){
#if DEBUG >= 1
std::cerr << "Pipe (out) creation failed for " << name << std::endl;
#endif
if ( *fdin == -1){
close(pipein[0]);
close(pipein[1]);
}
return 0;
}
if (fderr && *fderr == -1 && pipe(pipeerr) < 0){
#if DEBUG >= 1
std::cerr << "Pipe (err) creation failed for " << name << std::endl;
#endif
if ( *fdin == -1){
close(pipein[0]);
close(pipein[1]);
}
if ( *fdout == -1){
close(pipeout[0]);
close(pipeout[1]);
}
return 0;
}
int devnull = -1;
if ( !fdin || !fdout || !fderr){
devnull = open("/dev/null", O_RDWR);
if (devnull == -1){
#if DEBUG >= 1
std::cerr << "Could not open /dev/null for " << name << ": " << strerror(errno) << std::endl;
#endif
if ( *fdin == -1){
close(pipein[0]);
close(pipein[1]);
}
if ( *fdout == -1){
close(pipeout[0]);
close(pipeout[1]);
}
if ( *fderr == -1){
close(pipeerr[0]);
close(pipeerr[1]);
}
return 0;
}
}
pid = fork();
if (pid == 0){ //child
if ( !fdin){
dup2(devnull, STDIN_FILENO);
}else if ( *fdin == -1){
close(pipein[1]); // close unused write end
dup2(pipein[0], STDIN_FILENO);
close(pipein[0]);
}else if ( *fdin != STDIN_FILENO){
dup2( *fdin, STDIN_FILENO);
close( *fdin);
}
if ( !fdout){
dup2(devnull, STDOUT_FILENO);
}else if ( *fdout == -1){
close(pipeout[0]); // close unused read end
dup2(pipeout[1], STDOUT_FILENO);
close(pipeout[1]);
}else if ( *fdout != STDOUT_FILENO){
dup2( *fdout, STDOUT_FILENO);
close( *fdout);
}
if ( !fderr){
dup2(devnull, STDERR_FILENO);
}else if ( *fderr == -1){
close(pipeerr[0]); // close unused read end
dup2(pipeerr[1], STDERR_FILENO);
close(pipeerr[1]);
}else if ( *fderr != STDERR_FILENO){
dup2( *fderr, STDERR_FILENO);
close( *fderr);
}
if (devnull != -1){
close(devnull);
}
execvp(argv[0], argv);
#if DEBUG >= 1
perror("execvp failed");
#endif
exit(42);
}else if (pid == -1){
#if DEBUG >= 1
std::cerr << "Failed to fork for pipe: " << name << std::endl;
#endif
if (fdin && *fdin == -1){
close(pipein[0]);
close(pipein[1]);
}
if (fdout && *fdout == -1){
close(pipeout[0]);
close(pipeout[1]);
}
if (fderr && *fderr == -1){
close(pipeerr[0]);
close(pipeerr[1]);
}
if (devnull != -1){
close(devnull);
}
return 0;
}else{ //parent
#if DEBUG >= 1
std::cerr << "Piped process " << name << " started";
if (fdin ) std::cerr << " in=" << (*fdin == -1 ? pipein [1] : *fdin );
if (fdout) std::cerr << " out=" << (*fdout == -1 ? pipeout[0] : *fdout);
if (fderr) std::cerr << " err=" << (*fderr == -1 ? pipeerr[0] : *fderr);
if (devnull != -1) std::cerr << " null=" << devnull;
std::cerr << ", PID " << pid << ": " << argv[0] << std::endl;
#endif
if (devnull != -1){
close(devnull);
}
if (fdin && *fdin == -1){
close(pipein[0]); // close unused end end
*fdin = pipein[1];
}
if (fdout && *fdout == -1){
close(pipeout[1]); // close unused write end
*fdout = pipeout[0];
}
if (fderr && *fderr == -1){
close(pipeerr[1]); // close unused write end
*fderr = pipeerr[0];
}
plist.insert(std::pair<pid_t, std::string>(pid, name));
}
return pid;
}
/// Starts a new process with given fds if the name is not already active.
/// \return 0 if process was not started, process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Command for this process.
/// \arg fdin Standard input file descriptor. If null, /dev/null is assumed. Otherwise, if arg contains -1, a new fd is automatically allocated and written into this arg. Then the arg will be used as fd.
/// \arg fdout Same as fdin, but for stdout.
/// \arg fdout Same as fdin, but for stderr.
pid_t Util::Procs::StartPiped(std::string name, std::string cmd, int * fdin, int * fdout, int * fderr){
//Convert the given command to a char * []
char * tmp = (char*)cmd.c_str();
char * tmp2 = 0;
char * args[21];
int i = 0;
tmp2 = strtok(tmp, " ");
args[0] = tmp2;
while (tmp2 != 0 && (i < 20)){
tmp2 = strtok(0, " ");
++i;
args[i] = tmp2;
}
if (i == 20){
args[20] = 0;
}
return StartPiped(name,args,fdin,fdout,fderr);
}
pid_t Util::Procs::StartPiped2(std::string name, std::string cmd1, std::string cmd2, int * fdin, int * fdout, int * fderr1, int * fderr2){
int pfildes[2];
if (pipe(pfildes) == -1){
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. Pipe creation failed." << std::endl;
#endif
return 0;
}
pid_t res1 = StartPiped(name, cmd1, fdin, &pfildes[1], fderr1);
if ( !res1){
close(pfildes[1]);
close(pfildes[0]);
return 0;
}
pid_t res2 = StartPiped(name+"receiving", cmd2, &pfildes[0], fdout, fderr2);
if ( !res2){
Stop(res1);
close(pfildes[1]);
close(pfildes[0]);
return 0;
}
//we can close these because the fork in StartPiped() copies them.
close(pfildes[1]);
close(pfildes[0]);
return res1;
}
/// Stops the named process, if running.
/// \arg name (Internal) name of process to stop
void Util::Procs::Stop(std::string name){
int max = 5;
while (isActive(name)){
Stop(getPid(name));
max--;
if (max <= 0){
return;
}
}
}
/// Stops the process with this pid, if running.
/// \arg name The PID of the process to stop.
void Util::Procs::Stop(pid_t name){
if (isActive(name)){
kill(name, SIGTERM);
}
}
/// (Attempts to) stop all running child processes.
void Util::Procs::StopAll(){
std::map<pid_t, std::string> listcopy = plist;
std::map<pid_t, std::string>::iterator it;
for (it = listcopy.begin(); it != listcopy.end(); it++){
Stop(( *it).first);
}
}
/// Returns the number of active child processes.
int Util::Procs::Count(){
return plist.size();
}
/// Returns true if a process by this name is currently active.
bool Util::Procs::isActive(std::string name){
std::map<pid_t, std::string>::iterator it;
for (it = plist.begin(); it != plist.end(); it++){
if (( *it).second == name){
if (kill(( *it).first, 0) == 0){
return true;
}
}
}
return false;
}
/// Returns true if a process with this PID is currently active.
bool Util::Procs::isActive(pid_t name){
return (plist.count(name) == 1) && (kill(name, 0) == 0);
}
/// Gets PID for this named process, if active.
/// \return NULL if not active, process PID otherwise.
pid_t Util::Procs::getPid(std::string name){
std::map<pid_t, std::string>::iterator it;
for (it = plist.begin(); it != plist.end(); it++){
if (( *it).second == name){
return ( *it).first;
}
}
return 0;
}
/// Gets name for this process PID, if active.
/// \return Empty string if not active, name otherwise.
std::string Util::Procs::getName(pid_t name){
if (plist.count(name) == 1){
return plist[name];
}
return "";
}
/// Registers one notifier function for when a process indentified by PID terminates.
/// \return true if the notifier could be registered, false otherwise.
bool Util::Procs::SetTerminationNotifier(pid_t pid, TerminationNotifier notifier){
if (plist.find(pid) != plist.end()){
exitHandlers[pid] = notifier;
return true;
}
return false;
}