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/*
* thread.c: A simple thread base class
*
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* $Id: thread.c 2.3 2009/04/13 13:50:39 kls Exp $
*/
#include "thread.h"
#include <errno.h>
#include <linux/unistd.h>
#include <malloc.h>
#include <stdarg.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/prctl.h>
#include <unistd.h>
#include "tools.h"
static bool GetAbsTime(struct timespec *Abstime, int MillisecondsFromNow)
{
struct timeval now;
if (gettimeofday(&now, NULL) == 0) { // get current time
now.tv_sec += MillisecondsFromNow / 1000; // add full seconds
now.tv_usec += (MillisecondsFromNow % 1000) * 1000; // add microseconds
if (now.tv_usec >= 1000000) { // take care of an overflow
now.tv_sec++;
now.tv_usec -= 1000000;
}
Abstime->tv_sec = now.tv_sec; // seconds
Abstime->tv_nsec = now.tv_usec * 1000; // nano seconds
return true;
}
return false;
}
// --- cCondWait -------------------------------------------------------------
cCondWait::cCondWait(void)
{
signaled = false;
pthread_mutex_init(&mutex, NULL);
pthread_cond_init(&cond, NULL);
}
cCondWait::~cCondWait()
{
pthread_cond_broadcast(&cond); // wake up any sleepers
pthread_cond_destroy(&cond);
pthread_mutex_destroy(&mutex);
}
void cCondWait::SleepMs(int TimeoutMs)
{
cCondWait w;
w.Wait(max(TimeoutMs, 3)); // making sure the time is >2ms to avoid a possible busy wait
}
bool cCondWait::Wait(int TimeoutMs)
{
pthread_mutex_lock(&mutex);
if (!signaled) {
if (TimeoutMs) {
struct timespec abstime;
if (GetAbsTime(&abstime, TimeoutMs)) {
while (!signaled) {
if (pthread_cond_timedwait(&cond, &mutex, &abstime) == ETIMEDOUT)
break;
}
}
}
else
pthread_cond_wait(&cond, &mutex);
}
bool r = signaled;
signaled = false;
pthread_mutex_unlock(&mutex);
return r;
}
void cCondWait::Signal(void)
{
pthread_mutex_lock(&mutex);
signaled = true;
pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&mutex);
}
// --- cCondVar --------------------------------------------------------------
cCondVar::cCondVar(void)
{
pthread_cond_init(&cond, 0);
}
cCondVar::~cCondVar()
{
pthread_cond_broadcast(&cond); // wake up any sleepers
pthread_cond_destroy(&cond);
}
void cCondVar::Wait(cMutex &Mutex)
{
if (Mutex.locked) {
int locked = Mutex.locked;
Mutex.locked = 0; // have to clear the locked count here, as pthread_cond_wait
// does an implicit unlock of the mutex
pthread_cond_wait(&cond, &Mutex.mutex);
Mutex.locked = locked;
}
}
bool cCondVar::TimedWait(cMutex &Mutex, int TimeoutMs)
{
bool r = true; // true = condition signaled, false = timeout
if (Mutex.locked) {
struct timespec abstime;
if (GetAbsTime(&abstime, TimeoutMs)) {
int locked = Mutex.locked;
Mutex.locked = 0; // have to clear the locked count here, as pthread_cond_timedwait
// does an implicit unlock of the mutex.
if (pthread_cond_timedwait(&cond, &Mutex.mutex, &abstime) == ETIMEDOUT)
r = false;
Mutex.locked = locked;
}
}
return r;
}
void cCondVar::Broadcast(void)
{
pthread_cond_broadcast(&cond);
}
// --- cRwLock ---------------------------------------------------------------
cRwLock::cRwLock(bool PreferWriter)
{
pthread_rwlockattr_t attr;
pthread_rwlockattr_init(&attr);
pthread_rwlockattr_setkind_np(&attr, PreferWriter ? PTHREAD_RWLOCK_PREFER_WRITER_NP : PTHREAD_RWLOCK_PREFER_READER_NP);
pthread_rwlock_init(&rwlock, &attr);
}
cRwLock::~cRwLock()
{
pthread_rwlock_destroy(&rwlock);
}
bool cRwLock::Lock(bool Write, int TimeoutMs)
{
int Result = 0;
struct timespec abstime;
if (TimeoutMs) {
if (!GetAbsTime(&abstime, TimeoutMs))
TimeoutMs = 0;
}
if (Write)
Result = TimeoutMs ? pthread_rwlock_timedwrlock(&rwlock, &abstime) : pthread_rwlock_wrlock(&rwlock);
else
Result = TimeoutMs ? pthread_rwlock_timedrdlock(&rwlock, &abstime) : pthread_rwlock_rdlock(&rwlock);
return Result == 0;
}
void cRwLock::Unlock(void)
{
pthread_rwlock_unlock(&rwlock);
}
// --- cMutex ----------------------------------------------------------------
cMutex::cMutex(void)
{
locked = 0;
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK_NP);
pthread_mutex_init(&mutex, &attr);
}
cMutex::~cMutex()
{
pthread_mutex_destroy(&mutex);
}
void cMutex::Lock(void)
{
pthread_mutex_lock(&mutex);
locked++;
}
void cMutex::Unlock(void)
{
if (!--locked)
pthread_mutex_unlock(&mutex);
}
// --- cThread ---------------------------------------------------------------
tThreadId cThread::mainThreadId = 0;
cThread::cThread(const char *Description)
{
active = running = false;
childTid = 0;
childThreadId = 0;
description = NULL;
if (Description)
SetDescription("%s", Description);
}
cThread::~cThread()
{
Cancel(); // just in case the derived class didn't call it
free(description);
}
void cThread::SetPriority(int Priority)
{
if (setpriority(PRIO_PROCESS, 0, Priority) < 0)
LOG_ERROR;
}
void cThread::SetIOPriority(int Priority)
{
if (syscall(SYS_ioprio_set, 1, 0, (Priority & 0xff) | (2 << 13)) < 0) // best effort class
LOG_ERROR;
}
void cThread::SetDescription(const char *Description, ...)
{
free(description);
description = NULL;
if (Description) {
va_list ap;
va_start(ap, Description);
description = strdup(cString::sprintf(Description, ap));
va_end(ap);
}
}
void *cThread::StartThread(cThread *Thread)
{
Thread->childThreadId = ThreadId();
if (Thread->description) {
dsyslog("%s thread started (pid=%d, tid=%d)", Thread->description, getpid(), Thread->childThreadId);
#ifdef PR_SET_NAME
if (prctl(PR_SET_NAME, Thread->description, 0, 0, 0) < 0)
esyslog("%s thread naming failed (pid=%d, tid=%d)", Thread->description, getpid(), Thread->childThreadId);
#endif
}
Thread->Action();
if (Thread->description)
dsyslog("%s thread ended (pid=%d, tid=%d)", Thread->description, getpid(), Thread->childThreadId);
Thread->running = false;
Thread->active = false;
return NULL;
}
#define THREAD_STOP_TIMEOUT 3000 // ms to wait for a thread to stop before newly starting it
#define THREAD_STOP_SLEEP 30 // ms to sleep while waiting for a thread to stop
bool cThread::Start(void)
{
if (!running) {
if (active) {
// Wait until the previous incarnation of this thread has completely ended
// before starting it newly:
cTimeMs RestartTimeout;
while (!running && active && RestartTimeout.Elapsed() < THREAD_STOP_TIMEOUT)
cCondWait::SleepMs(THREAD_STOP_SLEEP);
}
if (!active) {
active = running = true;
if (pthread_create(&childTid, NULL, (void *(*) (void *))&StartThread, (void *)this) == 0) {
pthread_detach(childTid); // auto-reap
}
else {
LOG_ERROR;
active = running = false;
return false;
}
}
}
return true;
}
bool cThread::Active(void)
{
if (active) {
//
// Single UNIX Spec v2 says:
//
// The pthread_kill() function is used to request
// that a signal be delivered to the specified thread.
//
// As in kill(), if sig is zero, error checking is
// performed but no signal is actually sent.
//
int err;
if ((err = pthread_kill(childTid, 0)) != 0) {
if (err != ESRCH)
LOG_ERROR;
childTid = 0;
active = running = false;
}
else
return true;
}
return false;
}
void cThread::Cancel(int WaitSeconds)
{
running = false;
if (active && WaitSeconds > -1) {
if (WaitSeconds > 0) {
for (time_t t0 = time(NULL) + WaitSeconds; time(NULL) < t0; ) {
if (!Active())
return;
cCondWait::SleepMs(10);
}
esyslog("ERROR: %s thread %d won't end (waited %d seconds) - canceling it...", description ? description : "", childThreadId, WaitSeconds);
}
pthread_cancel(childTid);
childTid = 0;
active = false;
}
}
tThreadId cThread::ThreadId(void)
{
return syscall(__NR_gettid);
}
void cThread::SetMainThreadId(void)
{
if (mainThreadId == 0)
mainThreadId = ThreadId();
else
esyslog("ERROR: attempt to set main thread id to %d while it already is %d", ThreadId(), mainThreadId);
}
// --- cMutexLock ------------------------------------------------------------
cMutexLock::cMutexLock(cMutex *Mutex)
{
mutex = NULL;
locked = false;
Lock(Mutex);
}
cMutexLock::~cMutexLock()
{
if (mutex && locked)
mutex->Unlock();
}
bool cMutexLock::Lock(cMutex *Mutex)
{
if (Mutex && !mutex) {
mutex = Mutex;
Mutex->Lock();
locked = true;
return true;
}
return false;
}
// --- cThreadLock -----------------------------------------------------------
cThreadLock::cThreadLock(cThread *Thread)
{
thread = NULL;
locked = false;
Lock(Thread);
}
cThreadLock::~cThreadLock()
{
if (thread && locked)
thread->Unlock();
}
bool cThreadLock::Lock(cThread *Thread)
{
if (Thread && !thread) {
thread = Thread;
Thread->Lock();
locked = true;
return true;
}
return false;
}
// --- cPipe -----------------------------------------------------------------
// cPipe::Open() and cPipe::Close() are based on code originally received from
// Andreas Vitting <Andreas@huji.de>
cPipe::cPipe(void)
{
pid = -1;
f = NULL;
}
cPipe::~cPipe()
{
Close();
}
bool cPipe::Open(const char *Command, const char *Mode)
{
int fd[2];
if (pipe(fd) < 0) {
LOG_ERROR;
return false;
}
if ((pid = fork()) < 0) { // fork failed
LOG_ERROR;
close(fd[0]);
close(fd[1]);
return false;
}
const char *mode = "w";
int iopipe = 0;
if (pid > 0) { // parent process
if (strcmp(Mode, "r") == 0) {
mode = "r";
iopipe = 1;
}
close(fd[iopipe]);
if ((f = fdopen(fd[1 - iopipe], mode)) == NULL) {
LOG_ERROR;
close(fd[1 - iopipe]);
}
return f != NULL;
}
else { // child process
int iofd = STDOUT_FILENO;
if (strcmp(Mode, "w") == 0) {
mode = "r";
iopipe = 1;
iofd = STDIN_FILENO;
}
close(fd[iopipe]);
if (dup2(fd[1 - iopipe], iofd) == -1) { // now redirect
LOG_ERROR;
close(fd[1 - iopipe]);
_exit(-1);
}
else {
int MaxPossibleFileDescriptors = getdtablesize();
for (int i = STDERR_FILENO + 1; i < MaxPossibleFileDescriptors; i++)
close(i); //close all dup'ed filedescriptors
if (execl("/bin/sh", "sh", "-c", Command, NULL) == -1) {
LOG_ERROR_STR(Command);
close(fd[1 - iopipe]);
_exit(-1);
}
}
_exit(0);
}
}
int cPipe::Close(void)
{
int ret = -1;
if (f) {
fclose(f);
f = NULL;
}
if (pid > 0) {
int status = 0;
int i = 5;
while (i > 0) {
ret = waitpid(pid, &status, WNOHANG);
if (ret < 0) {
if (errno != EINTR && errno != ECHILD) {
LOG_ERROR;
break;
}
}
else if (ret == pid)
break;
i--;
cCondWait::SleepMs(100);
}
if (!i) {
kill(pid, SIGKILL);
ret = -1;
}
else if (ret == -1 || !WIFEXITED(status))
ret = -1;
pid = -1;
}
return ret;
}
// --- SystemExec ------------------------------------------------------------
int SystemExec(const char *Command, bool Detached)
{
pid_t pid;
if ((pid = fork()) < 0) { // fork failed
LOG_ERROR;
return -1;
}
if (pid > 0) { // parent process
int status = 0;
if (waitpid(pid, &status, 0) < 0) {
LOG_ERROR;
return -1;
}
return status;
}
else { // child process
if (Detached) {
// Fork again and let first child die - grandchild stays alive without parent
if (fork() > 0)
_exit(0);
// Start a new session
pid_t sid = setsid();
if (sid < 0)
LOG_ERROR;
// close STDIN and re-open as /dev/null
int devnull = open("/dev/null", O_RDONLY);
if (devnull < 0 || dup2(devnull, 0) < 0)
LOG_ERROR;
}
int MaxPossibleFileDescriptors = getdtablesize();
for (int i = STDERR_FILENO + 1; i < MaxPossibleFileDescriptors; i++)
close(i); //close all dup'ed filedescriptors
if (execl("/bin/sh", "sh", "-c", Command, NULL) == -1) {
LOG_ERROR_STR(Command);
_exit(-1);
}
_exit(0);
}
}
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