mistserver/lib/procs.cpp

462 lines
13 KiB
C++

/// \file procs.cpp
/// Contains generic functions for managing processes.
#include "procs.h"
#include "defines.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::set<pid_t> Util::Procs::plist;
std::set<int> Util::Procs::socketList;
bool Util::Procs::handler_set = false;
bool Util::Procs::thread_handler = false;
tthread::mutex Util::Procs::plistMutex;
tthread::thread * Util::Procs::reaper_thread = 0;
/// Local-only function. Attempts to reap child and returns current running status.
bool Util::Procs::childRunning(pid_t p) {
int status;
pid_t ret = waitpid(p, &status, WNOHANG);
if (ret == p) {
tthread::lock_guard<tthread::mutex> guard(plistMutex);
int exitcode = -1;
if (WIFEXITED(status)) {
exitcode = WEXITSTATUS(status);
} else if (WIFSIGNALED(status)) {
exitcode = -WTERMSIG(status);
}
if (plist.count(ret)) {
HIGH_MSG("Process %d fully terminated with code %d", ret, exitcode);
plist.erase(ret);
} else {
HIGH_MSG("Child process %d exited with code %d", ret, exitcode);
}
return false;
}
if (ret < 0 && errno == EINTR) {
return childRunning(p);
}
return !kill(p, 0);
}
/// sends sig 0 to process (pid). returns true if process is running
bool Util::Procs::isRunning(pid_t pid){
return !kill(pid, 0);
}
/// Called at exit of any program that used a Start* function.
/// Waits up to 1 second, then sends SIGINT signal to all managed processes.
/// After that waits up to 5 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() {
if (!handler_set){return;}
int waiting = 0;
std::set<pid_t> listcopy;
{
tthread::lock_guard<tthread::mutex> guard(plistMutex);
listcopy = plist;
thread_handler = false;
}
if (reaper_thread){
reaper_thread->join();
delete reaper_thread;
reaper_thread = 0;
}
std::set<pid_t>::iterator it;
if (listcopy.empty()) {
return;
}
//wait up to 0.5 second for applications to shut down
while (!listcopy.empty() && waiting <= 25) {
for (it = listcopy.begin(); it != listcopy.end(); it++) {
if (!childRunning(*it)) {
listcopy.erase(it);
break;
}
if (!listcopy.empty()) {
Util::wait(20);
++waiting;
}
}
}
if (listcopy.empty()) {
return;
}
INFO_MSG("Sending SIGINT and waiting up to 10 seconds for %d children to terminate.", (int)listcopy.size());
waiting = 0;
//wait up to 10 seconds for applications to shut down
while (!listcopy.empty() && waiting <= 500) {
bool doWait = true;
for (it = listcopy.begin(); it != listcopy.end(); it++) {
if (!childRunning(*it)) {
listcopy.erase(it);
doWait = false;
break;
}
}
if (doWait && !listcopy.empty()) {
if ((waiting % 50) == 0){
for (it = listcopy.begin(); it != listcopy.end(); it++) {
INFO_MSG("SIGINT %d", *it);
kill(*it, SIGINT);
}
}
Util::wait(20);
++waiting;
}
}
if (listcopy.empty()) {
return;
}
ERROR_MSG("Sending SIGKILL to remaining %d children", (int)listcopy.size());
//send sigkill to all remaining
if (!listcopy.empty()) {
for (it = listcopy.begin(); it != listcopy.end(); it++) {
INFO_MSG("SIGKILL %d", *it);
kill(*it, SIGKILL);
}
}
INFO_MSG("Waiting up to a second for %d children to terminate.", (int)listcopy.size());
waiting = 0;
//wait up to 1 second for applications to shut down
while (!listcopy.empty() && waiting <= 50) {
for (it = listcopy.begin(); it != listcopy.end(); it++) {
if (!childRunning(*it)) {
listcopy.erase(it);
break;
}
if (!listcopy.empty()) {
Util::wait(20);
++waiting;
}
}
}
if (listcopy.empty()) {
return;
}
FAIL_MSG("Giving up with %d children left.", (int)listcopy.size());
}
/// Sets up exit and childsig handlers.
/// Spawns grim_reaper. exit handler despawns grim_reaper
/// Called by every Start* function.
void Util::Procs::setHandler() {
tthread::lock_guard<tthread::mutex> guard(plistMutex);
if (!handler_set) {
thread_handler = true;
reaper_thread = new tthread::thread(grim_reaper, 0);
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;
}
}
///Thread that loops until thread_handler is false.
///Reaps available children and then sleeps for a second.
///Not done in signal handler so we can use a mutex to prevent race conditions.
void Util::Procs::grim_reaper(void * n){
VERYHIGH_MSG("Grim reaper start");
while (thread_handler){
{
tthread::lock_guard<tthread::mutex> guard(plistMutex);
int status;
pid_t ret = -1;
while (ret != 0) {
ret = waitpid(-1, &status, WNOHANG);
if (ret <= 0) { //ignore, would block otherwise
if (ret == 0 || errno != EINTR) {
break;
}
continue;
}
int exitcode;
if (WIFEXITED(status)) {
exitcode = WEXITSTATUS(status);
} else if (WIFSIGNALED(status)) {
exitcode = -WTERMSIG(status);
} else { // not possible
break;
}
if (plist.count(ret)) {
HIGH_MSG("Process %d fully terminated with code %d", ret, exitcode);
plist.erase(ret);
} else {
HIGH_MSG("Child process %d exited with code %d", ret, exitcode);
}
}
}
Util::sleep(500);
}
VERYHIGH_MSG("Grim reaper stop");
}
/// Ignores everything. Separate thread handles waiting for children.
void Util::Procs::childsig_handler(int signum) {
return;
}
/// Runs the given command and returns the stdout output as a string.
std::string Util::Procs::getOutputOf(char * const * argv) {
std::string ret;
int fin = 0, fout = -1, ferr = 0;
pid_t myProc = StartPiped(argv, &fin, &fout, &ferr);
while (childRunning(myProc)) {
Util::sleep(100);
}
FILE * outFile = fdopen(fout, "r");
char * fileBuf = 0;
size_t fileBufLen = 0;
while (!(feof(outFile) || ferror(outFile)) && (getline(&fileBuf, &fileBufLen, outFile) != -1)) {
ret += fileBuf;
}
fclose(outFile);
free(fileBuf);
return ret;
}
///This function prepares a deque for getOutputOf and automatically inserts a NULL at the end of the char* const*
char* const* Util::Procs::dequeToArgv(std::deque<std::string> & argDeq){
char** ret = (char**)malloc((argDeq.size()+1)*sizeof(char*));
for (int i = 0; i<argDeq.size(); i++){
ret[i] = (char*)argDeq[i].c_str();
}
ret[argDeq.size()] = NULL;
return ret;
}
std::string Util::Procs::getOutputOf(std::deque<std::string> & argDeq){
std::string ret;
char* const* argv = dequeToArgv(argDeq);//Note: Do not edit deque before executing command
ret = getOutputOf(argv);
return ret;
}
pid_t Util::Procs::StartPiped(std::deque<std::string> & argDeq, int * fdin, int * fdout, int * fderr) {
pid_t ret;
char* const* argv = dequeToArgv(argDeq);//Note: Do not edit deque before executing command
ret = Util::Procs::StartPiped(argv, fdin, fdout, fderr);
return ret;
}
/// 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 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(const char * const * argv, int * fdin, int * fdout, int * fderr) {
pid_t pid;
int pipein[2], pipeout[2], pipeerr[2];
setHandler();
if (fdin && *fdin == -1 && pipe(pipein) < 0) {
ERROR_MSG("stdin pipe creation failed for process %s, reason: %s", argv[0], strerror(errno));
return 0;
}
if (fdout && *fdout == -1 && pipe(pipeout) < 0) {
ERROR_MSG("stdout pipe creation failed for process %s, reason: %s", argv[0], strerror(errno));
if (*fdin == -1) {
close(pipein[0]);
close(pipein[1]);
}
return 0;
}
if (fderr && *fderr == -1 && pipe(pipeerr) < 0) {
ERROR_MSG("stderr pipe creation failed for process %s, reason: %s", argv[0], strerror(errno));
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) {
ERROR_MSG("Could not open /dev/null for process %s, reason: %s", argv[0], strerror(errno));
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
handler_set = false;
//Close all sockets in the socketList
for (std::set<int>::iterator it = Util::Procs::socketList.begin(); it != Util::Procs::socketList.end(); ++it){
close(*it);
}
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);
}
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);
}
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);
}
if (fdin && *fdin != -1 && *fdin != STDIN_FILENO) {
close(*fdin);
}
if (fdout && *fdout != -1 && *fdout != STDOUT_FILENO) {
close(*fdout);
}
if (fderr && *fderr != -1 && *fderr != STDERR_FILENO) {
close(*fderr);
}
if (devnull != -1) {
close(devnull);
}
//Because execvp requires a char* const* and we have a const char* const*
execvp(argv[0], (char* const*)argv);
ERROR_MSG("execvp failed for process %s, reason: %s", argv[0], strerror(errno));
exit(42);
} else if (pid == -1) {
ERROR_MSG("fork failed for process %s, reason: %s", argv[0], strerror(errno));
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
{
tthread::lock_guard<tthread::mutex> guard(plistMutex);
plist.insert(pid);
}
HIGH_MSG("Piped process %s started, PID %d", argv[0], pid);
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];
}
}
return pid;
}
/// Stops the process with this pid, if running.
/// \arg name The PID of the process to stop.
void Util::Procs::Stop(pid_t name) {
kill(name, SIGTERM);
}
/// Stops the process with this pid, if running.
/// \arg name The PID of the process to murder.
void Util::Procs::Murder(pid_t name) {
kill(name, SIGKILL);
}
/// (Attempts to) stop all running child processes.
void Util::Procs::StopAll() {
std::set<pid_t> listcopy;
{
tthread::lock_guard<tthread::mutex> guard(plistMutex);
listcopy = plist;
}
std::set<pid_t>::iterator it;
for (it = listcopy.begin(); it != listcopy.end(); it++) {
Stop(*it);
}
}
/// Returns the number of active child processes.
int Util::Procs::Count() {
tthread::lock_guard<tthread::mutex> guard(plistMutex);
return plist.size();
}
/// Returns true if a process with this PID is currently active.
bool Util::Procs::isActive(pid_t name) {
tthread::lock_guard<tthread::mutex> guard(plistMutex);
return (kill(name, 0) == 0);
}
/// Forget about the given PID, keeping it running on shutdown.
void Util::Procs::forget(pid_t pid) {
tthread::lock_guard<tthread::mutex> guard(plistMutex);
plist.erase(pid);
}
/// Remember the given PID, killing it on shutdown.
void Util::Procs::remember(pid_t pid) {
tthread::lock_guard<tthread::mutex> guard(plistMutex);
plist.insert(pid);
}