C++ pid_alive函数代码示例

static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
                              struct pid *pid, struct task_struct *p)
{
    struct user_namespace *user_ns = seq_user_ns(m);
    struct group_info *group_info;
    int g;
    struct fdtable *fdt = NULL;
    const struct cred *cred;
    pid_t ppid, tpid;

    rcu_read_lock();
    ppid = pid_alive(p) ?
           task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
    tpid = 0;
    if (pid_alive(p)) {
        struct task_struct *tracer = ptrace_parent(p);
        if (tracer)
            tpid = task_pid_nr_ns(tracer, ns);
    }
    cred = get_task_cred(p);
    seq_printf(m,
               "State:\t%s\n"
               "Tgid:\t%d\n"
               "Pid:\t%d\n"
               "PPid:\t%d\n"
               "TracerPid:\t%d\n"
               "Uid:\t%d\t%d\t%d\t%d\n"
               "Gid:\t%d\t%d\t%d\t%d\n",
               get_task_state(p),
               task_tgid_nr_ns(p, ns),
               pid_nr_ns(pid, ns),
               ppid, tpid,
               from_kuid_munged(user_ns, cred->uid),
               from_kuid_munged(user_ns, cred->euid),
               from_kuid_munged(user_ns, cred->suid),
               from_kuid_munged(user_ns, cred->fsuid),
               from_kgid_munged(user_ns, cred->gid),
               from_kgid_munged(user_ns, cred->egid),
               from_kgid_munged(user_ns, cred->sgid),
               from_kgid_munged(user_ns, cred->fsgid));

    task_lock(p);
    if (p->files)
        fdt = files_fdtable(p->files);
    seq_printf(m,
               "FDSize:\t%d\n"
               "Groups:\t",
               fdt ? fdt->max_fds : 0);
    rcu_read_unlock();

    group_info = cred->group_info;
    task_unlock(p);

    for (g = 0; g < group_info->ngroups; g++)
        seq_printf(m, "%d ",
                   from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
    put_cred(cred);

    seq_putc(m, '\n');
}

static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
				struct pid *pid, struct task_struct *p)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;
	const struct cred *cred;
	pid_t ppid, tpid, vpid;

	rcu_read_lock();
	ppid = pid_alive(p) ? ve_task_ppid_nr_ns(p, ns) : 0;

	tpid = 0;
	if (pid_alive(p)) {
		struct task_struct *tracer = tracehook_tracer_task(p);
		if (tracer)
			tpid = task_pid_nr_ns(tracer, ns);
	}
	vpid = task_virtual_pid(p);
	cred = get_task_cred(p);
	seq_printf(m,
		"State:\t%s\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		task_tgid_nr_ns(p, ns),
		pid_nr_ns(pid, ns),
		ppid, tpid,
		cred->uid, cred->euid, cred->suid, cred->fsuid,
		cred->gid, cred->egid, cred->sgid, cred->fsgid);

	task_utrace_proc_status(m, p);

	task_lock(p);
	if (p->files)
		fdt = files_fdtable(p->files);
	seq_printf(m,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = cred->group_info;
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
		seq_printf(m, "%d ", GROUP_AT(group_info, g));
	put_cred(cred);

	seq_printf(m, "\n");

	seq_printf(m, "envID:\t%d\nVPid:\t%d\n",
			p->ve_task_info.owner_env->veid, vpid);
	seq_printf(m, "StopState:\t%u\n", p->stopped_state);
}

static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
				struct pid *pid, struct task_struct *p)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;
	pid_t ppid, tpid;

	rcu_read_lock();
	ppid = pid_alive(p) ?
		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
	tpid = 0;
	if (pid_alive(p)) {
		struct task_struct *tracer = tracehook_tracer_task(p);
		if (tracer)
			tpid = task_pid_nr_ns(tracer, ns);
	}
	seq_printf(m,
		"State:\t%s\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		task_tgid_nr_ns(p, ns),
		pid_nr_ns(pid, ns),
		ppid, tpid,
		p->uid, p->euid, p->suid, p->fsuid,
		p->gid, p->egid, p->sgid, p->fsgid);

	task_lock(p);
	if (p->files)
		fdt = files_fdtable(p->files);
	seq_printf(m,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = p->group_info;
	get_group_info(group_info);
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
		seq_printf(m, "%d ", GROUP_AT(group_info, g));
	put_group_info(group_info);

	seq_printf(m, "\n");
}

/*
 * Check that the processes holding locks are still alive.
 */
static bool check_lock(lock_t *_lock)
{
	pid_t pid;

	/* We don't care about unlocked or locking-in-progress */
	if (_lock->lock != LOCKED)
		return FALSE;

	/* First the easy case. If it's held by a dead pid, release it. */
	pid = _lock->owner;

	/* if we're in the process of unlocking, it can show up as LOCKED
	 * but with no owner. Just bail, we'll try again next time around.
	 */
	if (pid == 0)
		return FALSE;

	if (pid_alive(pid) == FALSE) {
		if (errno != ESRCH)
			return TRUE;

		debugf("Found a lock held by dead pid %d. Freeing.\n", pid);
		unlock(_lock);
		return TRUE;
	}
	return FALSE;
}

static void check_lock(lock_t *_lock)
{
	pid_t pid;

	if (_lock->lock != LOCKED)
		return;

	/* First the easy case. If it's held by a dead pid, release it. */
	pid = _lock->owner;
	if (pid_alive(pid) == -1) {
		if (errno != ESRCH)
			return;

		debugf("Found a lock held by dead pid %d. Freeing.\n", pid);
		unlock(_lock);
		return;
	}

	/* If a pid has had a lock a long time, something is up. */
	if (_lock->contention > STEAL_THRESHOLD) {
		debugf("pid %d has held lock for too long. Releasing, and killing.\n", pid);
		kill_pid(pid);
		unlock(_lock);
		return;
	}
	return;
}

/* send kill to all forked processes */
void kill_child_checks(void) {
    int retval;
    pid_t pid;

    signal(SIGINT, SIG_IGN);
    pid = getpid();
    if(current_child_pid > 0 && current_child_pid != pid) {
        gm_log( GM_LOG_TRACE, "kill_child_checks(): send SIGINT to %d\n", current_child_pid);
        kill(-current_child_pid, SIGINT);
        kill(current_child_pid, SIGINT);
        sleep(1);
        if(waitpid(current_child_pid,&retval,WNOHANG)!=0) {
            signal(SIGINT, SIG_DFL);
            return;
        }
        if(pid_alive(current_child_pid)) {
            gm_log( GM_LOG_TRACE, "kill_child_checks(): send SIGKILL to %d\n", current_child_pid);
            kill(current_child_pid, SIGKILL);
        }
    }
    gm_log( GM_LOG_TRACE, "send SIGINT to %d\n", pid);
    kill(0, SIGINT);
    signal(SIGINT, SIG_DFL);
    return;
}

/* Main function for TLB walkthrough
 * Check accessed page every Memmap_wakeupsIinterval ms
 */
int Moca_MonitorThread(void * arg)
{
    task_data data;
    moca_task t;
    struct task_struct * task;
    //Init tlb walk data
    int pos;
    unsigned long long lastwake=0;

    MOCA_DEBUG_PRINT("Moca monitor thread alive \n");
    while(!kthread_should_stop())
    {
        pos=0;
        while((t=Moca_NextTask(&pos)))
        {
            data=t->data;
            task=(struct task_struct *)(t->key);
            MOCA_DEBUG_PRINT("Moca monitor thread testing task %p\n", task);
            if(pid_alive(task) && task->sched_info.last_arrival >= lastwake)
            {
                lastwake=task->sched_info.last_arrival;
                MOCA_DEBUG_PRINT("Moca monitor thread found task %p\n",task);
                Moca_MonitorPage(data);
            }
        }
        Moca_UpdateClock();
        MOCA_DEBUG_PRINT("Moca monitor thread going to sleep for %d\n",
                Moca_wakeupInterval);
        msleep(Moca_wakeupInterval);
    }
    MOCA_DEBUG_PRINT("Moca monitor thread finished\n");
    return 0;
}

// Add pid to the monitored process if pid is a monitored process
moca_task Moca_AddTaskIfNeeded(struct task_struct *t)
{
    moca_task ret=NULL;
    if(t && pid_alive(t) && t->real_parent && Moca_ShouldMonitorTask(t))
        ret=Moca_AddTask(t);
    return ret;
}

/*
 * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
 * tasks (sum on group iteration) belonging to @tsk's group.
 */
void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
{
	struct signal_struct *sig = tsk->signal;
	cputime_t utime, stime;
	struct task_struct *t;

	times->utime = sig->utime;
	times->stime = sig->stime;
	times->sum_exec_runtime = sig->sum_sched_runtime;

	rcu_read_lock();
	/* make sure we can trust tsk->thread_group list */
	if (!likely(pid_alive(tsk)))
		goto out;

	t = tsk;
	do {
		task_cputime(tsk, &utime, &stime);
		times->utime += utime;
		times->stime += stime;
		times->sum_exec_runtime += task_sched_runtime(t);
	} while_each_thread(tsk, t);
out:
	rcu_read_unlock();
}

void init_child(int childno)
{
	cpu_set_t set;
	pid_t pid = getpid();
	char childname[17];

	this_child = childno;

	set_seed(childno);

	shm->kill_count[childno] = 0;

	shm->num_mappings[childno] = 0;
	shm->mappings[childno] = zmalloc(sizeof(struct map));
	INIT_LIST_HEAD(&shm->mappings[childno]->list);

	setup_page_maps();

	if (sched_getaffinity(pid, sizeof(set), &set) == 0) {
		CPU_ZERO(&set);
		CPU_SET(childno, &set);
		sched_setaffinity(pid, sizeof(set), &set);
	}

	shm->child_syscall_count[childno] = 0;

	memset(childname, 0, sizeof(childname));
	sprintf(childname, "trinity-c%d", childno);
	prctl(PR_SET_NAME, (unsigned long) &childname);

	oom_score_adj(500);

	/* Wait for parent to set our pidslot */
	while (shm->pids[childno] != getpid()) {
		int ret = 0;

		/* Make sure parent is actually alive to wait for us. */
		ret = pid_alive(shm->mainpid);
		if (ret != 0) {
			shm->exit_reason = EXIT_SHM_CORRUPTION;
			outputerr(BUGTXT "parent (%d) went away!\n", shm->mainpid);
			sleep(20000);
		}
	}

	/* Wait for all the children to start up. */
	while (shm->ready == FALSE)
		sleep(1);

	set_make_it_fail();

	if (rand() % 100 < 50)
		use_fpu();

	mask_signals_child();

	disable_coredumps();
}

static inline char * task_state(struct task_struct *p, char *buffer)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;

	read_lock(&tasklist_lock);
	buffer += sprintf(buffer,
		"State:\t%s\n"
		"SleepAVG:\t%lu%%\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		(p->sleep_avg/1024)*100/(1020000000/1024),
	       	p->tgid,
		p->pid, pid_alive(p) ? p->group_leader->real_parent->tgid : 0,
		pid_alive(p) && p->ptrace ? p->parent->pid : 0,
		p->uid, p->euid, p->suid, p->fsuid,
		p->gid, p->egid, p->sgid, p->fsgid);
	read_unlock(&tasklist_lock);
	task_lock(p);
	rcu_read_lock();
	if (p->files)
		fdt = files_fdtable(p->files);
	buffer += sprintf(buffer,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = p->group_info;
	get_group_info(group_info);
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups,NGROUPS_SMALL); g++)
		buffer += sprintf(buffer, "%d ", GROUP_AT(group_info,g));
	put_group_info(group_info);

	buffer += sprintf(buffer, "\n");
	return buffer;
}

static inline void task_state(struct seq_file *m, struct pid *pid,
				struct task_struct *p)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;

	rcu_read_lock();
	seq_printf(m,
		"State:\t%s\n"
		"SleepAVG:\t%lu%%\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		(p->sleep_avg/1024)*100/(1020000000/1024),
	       	p->tgid, p->pid,
	       	pid_alive(p) ? rcu_dereference(p->real_parent)->tgid : 0,
		pid_alive(p) && p->ptrace ? rcu_dereference(p->parent)->pid : 0,
		p->uid, p->euid, p->suid, p->fsuid,
		p->gid, p->egid, p->sgid, p->fsgid);

	task_lock(p);
	if (p->files)
		fdt = files_fdtable(p->files);
	seq_printf(m,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = p->group_info;
	get_group_info(group_info);
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
		seq_printf(m, "%d ", GROUP_AT(group_info, g));
	put_group_info(group_info);

	seq_printf(m, "\n");
}

/* This is a special case for things like execve, which would replace our
 * child process with something unknown to us. We use a 'throwaway' process
 * to do the execve in, and let it run for a max of a second before we kill it
 */
static void do_extrafork(struct syscallrecord *rec)
{
	pid_t pid = 0;
	pid_t extrapid;

	extrapid = fork();
	if (extrapid == 0) {
		/* grand-child */
		char childname[]="trinity-subchild";
		prctl(PR_SET_NAME, (unsigned long) &childname);

		__do_syscall(rec, GOING_AWAY);
		/* if this was for eg. an successful execve, we should never get here.
		 * if it failed though... */
		_exit(EXIT_SUCCESS);
	}

	/* misc failure. */
	if (extrapid == -1) {
		//debugf("Couldn't fork grandchild: %s\n", strerror(errno));
		return;
	}

	/* small pause to let grandchild do some work. */
	if (pid_alive(extrapid) == TRUE)
		usleep(100);

	/* We take the rec lock here even though we don't obviously use it.
	 * The reason, is that the grandchild is using it. */
	lock(&rec->lock);
	while (pid == 0) {
		int childstatus;

		pid = waitpid(extrapid, &childstatus, WUNTRACED | WCONTINUED | WNOHANG);
		if (pid_alive(extrapid) == TRUE)
			kill(extrapid, SIGKILL);
		usleep(1000);
	}
	unlock(&rec->lock);
}

static void timer_function(unsigned long par)
{ 
  ushort cpu_share; 

  if (unlikely(!pid_alive(check_task))) {
    del_timer(&check_timer);
    printk(KERN_INFO "sendsig: cannot find pid %i. Is the process still active? Timer removed\n", pid);
    return;
  }

  cpu_share = thread_group_cpu_share(check_task);

  if (cpu_share >= max_cpu_share) {
    count_check++;
    printk(KERN_INFO "sendsig: current cpu share over limit of %i (check #%i)\n", 
	   max_cpu_share, count_check);

/* the ratio is: if the process has a cpu share higher than
   max_cpu_share for more than max_checks * wait_timeout seconds, then
   we'll send the signal sig_to_send to it
 */    
    if (count_check >= max_checks) {
      /*
	sending the signal to the process
      */
      signal_send(check_task);
      /*
	remove the timer
      */ 
      del_timer(&check_timer);
      printk(KERN_INFO "sendsig: sent signal to process %i, timer removed\n", pid);
      return;
    } 
  } else {
    /*
      if the process is being good, let's reset its counter
    */
    count_check = 0;
  }  
  /*
    update the timer
  */
  mod_timer(&check_timer, jiffies + wait_timeout * HZ); 

  return;
}

static void restart_lost_procs(void)
{
	svc_t *svc;

	for (svc = svc_iterator(1); svc; svc = svc_iterator(0)) {
		if (svc->pid > 0 && pid_alive(svc->pid))
			continue;

		/* Only restart lost daemons, not task/run/inetd services */
		if (SVC_TYPE_SERVICE != svc->type) {
			svc->pid = 0;
			continue;
		}

		service_start(svc);
	}
}