haiku/src/system/kernel/team.c

/*
 * Copyright 2002-2007, Axel Dörfler, axeld@pinc-software.de.
 * Distributed under the terms of the MIT License.
 *
 * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
 * Distributed under the terms of the NewOS License.
 */

/* Team functions */

#include <OS.h>

#include <elf.h>
#include <file_cache.h>
#include <int.h>
#include <kernel.h>
#include <kimage.h>
#include <kscheduler.h>
#include <port.h>
#include <sem.h>
#include <syscall_process_info.h>
#include <syscalls.h>
#include <team.h>
#include <tls.h>
#include <user_runtime.h>
#include <vfs.h>
#include <vm.h>
#include <vm_address_space.h>
#include <util/khash.h>

#include <sys/wait.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

//#define TRACE_TEAM
#ifdef TRACE_TEAM
#	define TRACE(x) dprintf x
#else
#	define TRACE(x) ;
#endif


struct team_key {
	team_id id;
};

struct team_arg {
	uint32	arg_count;
	char	**args;
	uint32	env_count;
	char	**env;
};

struct fork_arg {
	area_id		user_stack_area;
	addr_t		user_stack_base;
	size_t		user_stack_size;
	addr_t		user_local_storage;
	sigset_t	sig_block_mask;

	struct arch_fork_arg arch_info;
};


static void *sTeamHash = NULL;
static void *sGroupHash = NULL;
static struct team *sKernelTeam = NULL;

// some arbitrary chosen limits - should probably depend on the available
// memory (the limit is not yet enforced)
static int32 sMaxTeams = 2048;
static int32 sUsedTeams = 1;

spinlock team_spinlock = 0;


//	#pragma mark - Private functions


static void
_dump_team_info(struct team *team)
{
	kprintf("TEAM: %p\n", team);
	kprintf("id:          0x%lx\n", team->id);
	kprintf("name:        '%s'\n", team->name);
	kprintf("args:        '%s'\n", team->args);
	kprintf("next:        %p\n", team->next);
	kprintf("parent:      %p", team->parent);
	if (team->parent != NULL) {
		kprintf(" (id = 0x%lx)\n", team->parent->id);
	} else
		kprintf("\n");

	kprintf("children:    %p\n", team->children);
	kprintf("num_threads: %d\n", team->num_threads);
	kprintf("state:       %d\n", team->state);
	kprintf("pending_signals: 0x%x\n", team->pending_signals);
	kprintf("io_context:  %p\n", team->io_context);
	if (team->address_space)
		kprintf("address_space: %p (id = 0x%lx)\n", team->address_space, team->address_space->id);
	kprintf("main_thread: %p\n", team->main_thread);
	kprintf("thread_list: %p\n", team->thread_list);
	kprintf("group_id:    0x%lx\n", team->group_id);
	kprintf("session_id:  0x%lx\n", team->session_id);
}


static int
dump_team_info(int argc, char **argv)
{
	struct hash_iterator iterator;
	struct team *team;
	team_id id = -1;
	bool found = false;

	if (argc != 2) {
		kprintf("usage: team [id/address/name]\n");
		return 0;
	}

	id = strtoul(argv[1], NULL, 0);
	if (IS_KERNEL_ADDRESS(id)) {
		// semi-hack
		_dump_team_info((struct team *)id);
		return 0;
	}

	// walk through the thread list, trying to match name or id
	hash_open(sTeamHash, &iterator);
	while ((team = hash_next(sTeamHash, &iterator)) != NULL) {
		if ((team->name && strcmp(argv[1], team->name) == 0) || team->id == id) {
			_dump_team_info(team);
			found = true;
			break;
		}
	}
	hash_close(sTeamHash, &iterator, false);

	if (!found)
		kprintf("team \"%s\" (%ld) doesn't exist!\n", argv[1], id);
	return 0;
}


static int
dump_teams(int argc, char **argv)
{
	struct hash_iterator iterator;
	struct team *team;

	kprintf("team          id  parent      name\n");
	hash_open(sTeamHash, &iterator);

	while ((team = hash_next(sTeamHash, &iterator)) != NULL) {
		kprintf("%p%6lx  %p  %s\n", team, team->id, team->parent, team->name);
	}

	hash_close(sTeamHash, &iterator, false);
	return 0;
}


/**	Frees an array of strings in kernel space.
 *
 *	\param strings strings array
 *	\param count number of strings in array
 */

static void
free_strings_array(char **strings, int32 count)
{
	int32 i;

	if (strings == NULL)
		return;

	for (i = 0; i < count; i++)
		free(strings[i]);

    free(strings);
}


/**	Copy an array of strings in kernel space
 *
 *	\param strings strings array to be copied
 *	\param count number of strings in array
 *	\param kstrings	pointer to the kernel copy
 *	\return \c B_OK on success, or an appropriate error code on
 *		failure.
 */

static status_t
kernel_copy_strings_array(char * const *in, int32 count, char ***_strings)
{
	status_t status;
	char **strings;
	int32 i = 0;

	strings = (char **)malloc((count + 1) * sizeof(char *));
	if (strings == NULL)
		return B_NO_MEMORY;

	for (; i < count; i++) {
		strings[i] = strdup(in[i]);
		if (strings[i] == NULL) {
			status = B_NO_MEMORY;
			goto error;
		}
	}

	strings[count] = NULL;
	*_strings = strings;

	return B_OK;

error:
	free_strings_array(strings, i);
	return status;
}


/**	Copy an array of strings from user space to kernel space
 *
 *	\param strings userspace strings array
 *	\param count number of strings in array
 *	\param kstrings	pointer to the kernel copy
 *	\return \c B_OK on success, or an appropriate error code on
 *		failure.
 */

static status_t
user_copy_strings_array(char * const *userStrings, int32 count, char ***_strings)
{
	char *buffer;
	char **strings;
	status_t err;
	int32 i = 0;

	if (!IS_USER_ADDRESS(userStrings))
		return B_BAD_ADDRESS;

	// buffer for safely accessing the user string
	// TODO: maybe have a user_strdup() instead?
	buffer = (char *)malloc(4 * B_PAGE_SIZE);
	if (buffer == NULL)
		return B_NO_MEMORY;

	strings = (char **)malloc((count + 1) * sizeof(char *));
	if (strings == NULL) {
		err = B_NO_MEMORY;
		goto error;
	}

	if ((err = user_memcpy(strings, userStrings, count * sizeof(char *))) < B_OK)
		goto error;

	// scan all strings and copy to kernel space

	for (; i < count; i++) {
		err = user_strlcpy(buffer, strings[i], 4 * B_PAGE_SIZE);
		if (err < B_OK)
			goto error;

		strings[i] = strdup(buffer);
		if (strings[i] == NULL) {
			err = B_NO_MEMORY;
			goto error;
		}
	}

	strings[count] = NULL;
	*_strings = strings;
	free(buffer);

	return B_OK;

error:
	free_strings_array(strings, i);
	free(buffer);

	TRACE(("user_copy_strings_array failed %ld\n", err));
	return err;
}


static status_t
copy_strings_array(char * const *strings, int32 count, char ***_strings,
	bool kernel)
{
	if (kernel)
		return kernel_copy_strings_array(strings, count, _strings);

	return user_copy_strings_array(strings, count, _strings);
}


static int
team_struct_compare(void *_p, const void *_key)
{
	struct team *p = _p;
	const struct team_key *key = _key;

	if (p->id == key->id)
		return 0;

	return 1;
}


static uint32
team_struct_hash(void *_p, const void *_key, uint32 range)
{
	struct team *p = _p;
	const struct team_key *key = _key;

	if (p != NULL)
		return p->id % range;

	return (uint32)key->id % range;
}


static int
process_group_compare(void *_group, const void *_key)
{
	struct process_group *group = _group;
	const struct team_key *key = _key;

	if (group->id == key->id)
		return 0;

	return 1;
}


static uint32
process_group_hash(void *_group, const void *_key, uint32 range)
{
	struct process_group *group = _group;
	const struct team_key *key = _key;

	if (group != NULL)
		return group->id % range;

	return (uint32)key->id % range;
}


static void
insert_team_into_parent(struct team *parent, struct team *team)
{
	ASSERT(parent != NULL);

	team->siblings_next = parent->children;
	parent->children = team;
	team->parent = parent;
}


/**	Note: must have TEAM lock held
 */

static void
remove_team_from_parent(struct team *parent, struct team *team)
{
	struct team *child, *last = NULL;

	for (child = parent->children; child != NULL; child = child->siblings_next) {
		if (child == team) {
			if (last == NULL)
				parent->children = child->siblings_next;
			else
				last->siblings_next = child->siblings_next;

			team->parent = NULL;
			break;
		}
		last = child;
	}
}


/**	Reparent each of our children
 *	Note: must have TEAM lock held
 */

static void
reparent_children(struct team *team)
{
	struct team *child;

	while ((child = team->children) != NULL) {
		// remove the child from the current proc and add to the parent
		remove_team_from_parent(team, child);
		insert_team_into_parent(sKernelTeam, child);
	}
}


static bool
is_process_group_leader(struct team *team)
{
	return team->group_id == team->id;
}


/**	You must hold the team lock when calling this function. */

static void
insert_group_into_session(struct process_session *session, struct process_group *group)
{
	if (group == NULL)
		return;

	group->session = session;
	hash_insert(sGroupHash, group);
	session->group_count++;
}


/**	You must hold the team lock when calling this function. */

static void
insert_team_into_group(struct process_group *group, struct team *team)
{
	team->group = group;
	team->group_id = group->id;
	team->session_id = group->session->id;

	team->group_next = group->teams;
	group->teams = team;
}


/** Removes a group from a session, and puts the session object
 *	back into the session cache, if it's not used anymore.
 *	You must hold the team lock when calling this function.
 */

static void
remove_group_from_session(struct process_group *group)
{
	struct process_session *session = group->session;

	// the group must be in any session to let this function have any effect
	if (session == NULL)
		return;

	hash_remove(sGroupHash, group);

	// we cannot free the resource here, so we're keeping the group link
	// around - this way it'll be freed by free_process_group()
	if (--session->group_count > 0)
		group->session = NULL;
}




/**	Removes the team from the group. If that group becomes therefore
 *	unused, it will set \a _freeGroup to point to the group - otherwise
 *	it will be \c NULL.
 *	It cannot be freed here because this function has to be called
 *	with having the team lock held.
 *
 *	\param team the team that'll be removed from it's group
 *	\param _freeGroup points to the group to be freed or NULL
 */

static void
remove_team_from_group(struct team *team, struct process_group **_freeGroup)
{
	struct process_group *group = team->group;
	struct team *current, *last = NULL;

	*_freeGroup = NULL;

	// the team must be in any team to let this function have any effect
	if  (group == NULL)
		return;

	for (current = group->teams; current != NULL; current = current->group_next) {
		if (current == team) {
			if (last == NULL)
				group->teams = current->group_next;
			else
				last->group_next = current->group_next;

			team->group = NULL;
			break;
		}
		last = current;
	}

	team->group = NULL;
	team->group_next = NULL;

	if (group->teams != NULL)
		return;

	// we can remove this group as it is no longer used

	remove_group_from_session(group);
	*_freeGroup = group;
}


static struct process_group *
create_process_group(pid_t id)
{
	struct process_group *group = (struct process_group *)malloc(sizeof(struct process_group));
	if (group == NULL)
		return NULL;

	group->id = id;
	group->session = NULL;
	group->teams = NULL;
	return group;
}


static struct process_session *
create_process_session(pid_t id)
{
	struct process_session *session = (struct process_session *)malloc(sizeof(struct process_session));
	if (session == NULL)
		return NULL;

	session->id = id;
	session->group_count = 0;

	return session;
}


static struct team *
create_team_struct(const char *name, bool kernel)
{
	struct team *team = (struct team *)malloc(sizeof(struct team));
	if (team == NULL)
		return NULL;

	team->next = team->siblings_next = team->children = team->parent = NULL;
	team->id = allocate_thread_id();
	strlcpy(team->name, name, B_OS_NAME_LENGTH);
	team->args[0] = '\0';
	team->num_threads = 0;
	team->io_context = NULL;
	team->address_space = NULL;
	team->thread_list = NULL;
	team->main_thread = NULL;
	team->loading_info = NULL;
	team->state = TEAM_STATE_BIRTH;
	team->pending_signals = 0;
	team->death_sem = -1;

	team->dead_threads_kernel_time = 0;
	team->dead_threads_user_time = 0;

	list_init(&team->dead_children.list);
	team->dead_children.count = 0;
	team->dead_children.wait_for_any = 0;
	team->dead_children.waiters = 0;
	team->dead_children.kernel_time = 0;
	team->dead_children.user_time = 0;
	team->dead_children.sem = create_sem(0, "dead children");
	if (team->dead_children.sem < B_OK)
		goto error1;

	list_init(&team->image_list);
	list_init(&team->watcher_list);

	clear_team_debug_info(&team->debug_info, true);

	if (arch_team_init_team_struct(team, kernel) < 0)
		goto error2;

	return team;

error2:
	delete_sem(team->dead_children.sem);
error1:
	free(team);
	return NULL;
}


static void
delete_team_struct(struct team *team)
{
	struct death_entry *death;

	delete_sem(team->dead_children.sem);

	while ((death = list_remove_head_item(&team->dead_children.list)) != NULL)
		free(death);

	free(team);
}


static uint32
get_arguments_data_size(char **args, int32 argc)
{
	uint32 size = 0;
	int32 count;

	for (count = 0; count < argc; count++)
		size += strlen(args[count]) + 1;

	return size + (argc + 1) * sizeof(char *) + sizeof(struct uspace_program_args);
}


static void
free_team_arg(struct team_arg *teamArg)
{
	free_strings_array(teamArg->args, teamArg->arg_count);
	free_strings_array(teamArg->env, teamArg->env_count);

	free(teamArg);
}


static status_t
create_team_arg(struct team_arg **_teamArg, int32 argCount, char * const *args,
	int32 envCount, char * const *env, bool kernel)
{
	status_t status;
	char **argsCopy;
	char **envCopy;

	struct team_arg *teamArg = (struct team_arg *)malloc(sizeof(struct team_arg));
	if (teamArg == NULL)
		return B_NO_MEMORY;

	// copy the args over
	
	status = copy_strings_array(args, argCount, &argsCopy, kernel);
	if (status != B_OK)
		return status;

	status = copy_strings_array(env, envCount, &envCopy, kernel);
	if (status != B_OK) {
		free_strings_array(argsCopy, argCount);
		return status;
	}

	teamArg->arg_count = argCount;
	teamArg->args = argsCopy;
	teamArg->env_count = envCount;
	teamArg->env = envCopy;

	*_teamArg = teamArg;
	return B_OK;
}


static int32
team_create_thread_start(void *args)
{
	status_t err;
	struct thread *t;
	struct team *team;
	struct team_arg *teamArgs = args;
	const char *path;
	addr_t entry;
	char ustack_name[128];
	uint32 sizeLeft;
	char **uargs;
	char **uenv;
	char *udest;
	struct uspace_program_args *uspa;
	uint32 argCount, envCount, i;

	t = thread_get_current_thread();
	team = t->team;
	cache_node_launched(teamArgs->arg_count, teamArgs->args);

	TRACE(("team_create_thread_start: entry thread %ld\n", t->id));

	// create an initial primary stack area

	// Main stack area layout is currently as follows (starting from 0):
	//
	// size							| usage
	// -----------------------------+--------------------------------
	// USER_MAIN_THREAD_STACK_SIZE	| actual stack
	// TLS_SIZE						| TLS data
	// ENV_SIZE						| environment variables
	// arguments size				| arguments passed to the team

	// ToDo: ENV_SIZE is a) limited, and b) not used after libroot copied it to the heap
	// ToDo: we could reserve the whole USER_STACK_REGION upfront...

	sizeLeft = PAGE_ALIGN(USER_MAIN_THREAD_STACK_SIZE + TLS_SIZE + ENV_SIZE +
		get_arguments_data_size(teamArgs->args, teamArgs->arg_count));
	t->user_stack_base = USER_STACK_REGION + USER_STACK_REGION_SIZE - sizeLeft;
	t->user_stack_size = USER_MAIN_THREAD_STACK_SIZE;
		// the exact location at the end of the user stack area

	sprintf(ustack_name, "%s_main_stack", team->name);
	t->user_stack_area = create_area_etc(team, ustack_name, (void **)&t->user_stack_base,
		B_EXACT_ADDRESS, sizeLeft, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA | B_STACK_AREA);
	if (t->user_stack_area < 0) {
		dprintf("team_create_thread_start: could not create default user stack region\n");

		free_team_arg(teamArgs);
		return t->user_stack_area;
	}

	// now that the TLS area is allocated, initialize TLS
	arch_thread_init_tls(t);

	argCount = teamArgs->arg_count;
	envCount = teamArgs->env_count;

	uspa = (struct uspace_program_args *)(t->user_stack_base + t->user_stack_size
		+ TLS_SIZE + ENV_SIZE);
	uargs = (char **)(uspa + 1);
	udest = (char *)(uargs + argCount + 1);

	TRACE(("addr: stack base = 0x%lx, uargs = %p, udest = %p, sizeLeft = %lu\n",
		t->user_stack_base, uargs, udest, sizeLeft));

	sizeLeft = t->user_stack_base + sizeLeft - (addr_t)udest;

	for (i = 0; i < argCount; i++) {
		ssize_t length = user_strlcpy(udest, teamArgs->args[i], sizeLeft);
		if (length < B_OK) {
			argCount = 0;
			break;
		}

		uargs[i] = udest;
		udest += ++length;
		sizeLeft -= length;
	}
	uargs[argCount] = NULL;

	uenv = (char **)(t->user_stack_base + t->user_stack_size + TLS_SIZE);
	sizeLeft = ENV_SIZE;
	udest = (char *)uenv + ENV_SIZE - 1;
		// the environment variables are copied from back to front

	TRACE(("team_create_thread_start: envc: %ld, env: %p\n",
		teamArgs->env_count, (void *)teamArgs->env));

	for (i = 0; i < envCount; i++) {
		ssize_t length = strlen(teamArgs->env[i]) + 1;
		udest -= length;
		if (udest < (char *)&uenv[envCount]) {
			envCount = i;
			break;
		}

		uenv[i] = udest;

		if (user_memcpy(udest, teamArgs->env[i], length) < B_OK) {
			envCount = 0;
			break;
		}

		sizeLeft -= length;
	}
	uenv[envCount] = NULL;

	path = teamArgs->args[0];
	user_memcpy(uspa->program_path, path, sizeof(uspa->program_path));
	uspa->argc = argCount;
	uspa->argv = uargs;
	uspa->envc = envCount;
	uspa->envp = uenv;

	TRACE(("team_create_thread_start: loading elf binary '%s'\n", path));

	// add args to info member
	team->args[0] = 0;
	strlcpy(team->args, path, sizeof(team->args));
	for (i = 1; i < argCount; i++) {
		strlcat(team->args, " ", sizeof(team->args));
		strlcat(team->args, teamArgs->args[i], sizeof(team->args));
	}

	free_team_arg(teamArgs);
		// the arguments are already on the user stack, we no longer need them in this form

	// ToDo: don't use fixed paths!
	err = elf_load_user_image("/boot/beos/system/runtime_loader", team, 0, &entry);
	if (err < B_OK) {
		// Luckily, we don't have to clean up the mess we created - that's
		// done for us by the normal team deletion process
		TRACE(("team_create_thread_start: error when elf_load_user_image() %s\n", strerror(err))); 
		return err;
	}

	TRACE(("team_create_thread_start: loaded elf. entry = 0x%lx\n", entry));

	team->state = TEAM_STATE_NORMAL;

	// jump to the entry point in user space
	return arch_thread_enter_userspace(t, entry, uspa, NULL);
		// only returns in case of error
}


/** The BeOS kernel exports a function with this name, but most probably with
 *	different parameters; we should not make it public.
 */

static thread_id
load_image_etc(int32 argCount, char * const *args, int32 envCount, char * const *env,
	int32 priority, uint32 flags, bool kernel)
{
	struct process_group *group;
	struct team *team, *parent;
	const char *threadName;
	thread_id thread;
	status_t status;
	cpu_status state;
	struct team_arg *teamArgs;
	struct team_loading_info loadingInfo;

	if (args == NULL || argCount == 0)
		return B_BAD_VALUE;

	TRACE(("load_image_etc: name '%s', args = %p, argCount = %ld\n",
		args[0], args, argCount));

	team = create_team_struct(args[0], false);
	if (team == NULL)
		return B_NO_MEMORY;

	parent = thread_get_current_thread()->team;

	if (flags & B_WAIT_TILL_LOADED) {
		loadingInfo.thread = thread_get_current_thread();
		loadingInfo.result = B_ERROR;
		loadingInfo.done = false;
		team->loading_info = &loadingInfo;
	}

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	hash_insert(sTeamHash, team);
	insert_team_into_parent(parent, team);
	insert_team_into_group(parent->group, team);
	sUsedTeams++;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	status = create_team_arg(&teamArgs, argCount, args, envCount, env, kernel);
	if (status != B_OK)
		goto err1;

	// create a new io_context for this team
	team->io_context = vfs_new_io_context(parent->io_context);
	if (!team->io_context) {
		status = B_NO_MEMORY;
		goto err2;
	}

	// create an address space for this team
	status = vm_create_address_space(team->id, USER_BASE, USER_SIZE, false,
		&team->address_space);
	if (status < B_OK)
		goto err3;

	// cut the path from the main thread name
	threadName = strrchr(args[0], '/');
	if (threadName != NULL)
		threadName++;
	else
		threadName = args[0];

	// Create a kernel thread, but under the context of the new team
	// The new thread will take over ownership of teamArgs
	thread = spawn_kernel_thread_etc(team_create_thread_start, threadName, B_NORMAL_PRIORITY,
				teamArgs, team->id, team->id);
	if (thread < 0) {
		status = thread;
		goto err4;
	}

	// wait for the loader of the new team to finish its work
	if (flags & B_WAIT_TILL_LOADED) {
		struct thread *mainThread;

		state = disable_interrupts();
		GRAB_THREAD_LOCK();

		mainThread = thread_get_thread_struct_locked(thread);
		if (mainThread) {
			// resume the team's main thread
			if (mainThread->state == B_THREAD_SUSPENDED) {
				mainThread->state = mainThread->next_state = B_THREAD_READY;
				scheduler_enqueue_in_run_queue(mainThread);
			}

			// Now suspend ourselves until loading is finished.
			// We will be woken either by the thread, when it finished or
			// aborted loading, or when the team is going to die (e.g. is
			// killed). In either case the one setting `loadingInfo.done' is
			// responsible for removing the info from the team structure.
			while (!loadingInfo.done) {
				thread_get_current_thread()->next_state = B_THREAD_SUSPENDED;
				scheduler_reschedule();
			}
		} else {
			// Impressive! Someone managed to kill the thread in this short
			// time.
		}

		RELEASE_THREAD_LOCK();
		restore_interrupts(state);

		if (loadingInfo.result < B_OK)
			return loadingInfo.result;
	}	

	// notify the debugger
	user_debug_team_created(team->id);

	return thread;

err4:
	vm_put_address_space(team->address_space);
err3:
	vfs_free_io_context(team->io_context);
err2:
	free_team_arg(teamArgs);
err1:
	// remove the team structure from the team hash table and delete the team structure
	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	remove_team_from_group(team, &group);
	remove_team_from_parent(parent, team);
	hash_remove(sTeamHash, team);

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	team_delete_process_group(group);
	delete_team_struct(team);

	return status;
}


/**	Almost shuts down the current team and loads a new image into it.
 *	If successful, this function does not return and will takeover ownership of
 *	the arguments provided.
 *	This function may only be called from user space.
 */

static status_t
exec_team(const char *path, int32 argCount, char * const *args,
	int32 envCount, char * const *env)
{
	struct team *team = thread_get_current_thread()->team;
	struct team_arg *teamArgs;
	const char *threadName;
	status_t status = B_OK;
	cpu_status state;
	struct thread *thread;
	thread_id nubThreadID = -1;

	TRACE(("exec_team(path = \"%s\", argc = %ld, envCount = %ld): team %lx\n", args[0], argCount, envCount, team->id));

	// switching the kernel at run time is probably not a good idea :)
	if (team == team_get_kernel_team())
		return B_NOT_ALLOWED;

	// we currently need to be single threaded here
	// ToDo: maybe we should just kill all other threads and
	//	make the current thread the team's main thread?
	if (team->main_thread != thread_get_current_thread())
		return B_NOT_ALLOWED;

	// The debug nub thread, a pure kernel thread, is allowed to survive.
	// We iterate through the thread list to make sure that there's no other
	// thread.
	state = disable_interrupts();
	GRAB_TEAM_LOCK();
	GRAB_TEAM_DEBUG_INFO_LOCK(team->debug_info);

	if (team->debug_info.flags & B_TEAM_DEBUG_DEBUGGER_INSTALLED)
		nubThreadID = team->debug_info.nub_thread;

	RELEASE_TEAM_DEBUG_INFO_LOCK(team->debug_info);

	for (thread = team->thread_list; thread; thread = thread->team_next) {
		if (thread != team->main_thread && thread->id != nubThreadID) {
			status = B_NOT_ALLOWED;
			break;
		}
	}

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (status != B_OK)
		return status;

	// ToDo: maybe we should make sure upfront that the target path is an app?

	status = create_team_arg(&teamArgs, argCount, args, envCount, env, false);
	if (status != B_OK)
		return status;

	// replace args[0] with the path argument, just to be on the safe side
	free(teamArgs->args[0]);
	teamArgs->args[0] = strdup(path);

	// ToDo: remove team resources if there are any left
	// alarm, signals
	// thread_atkernel_exit() might not be called at all

	user_debug_prepare_for_exec();

	vm_delete_areas(team->address_space);
	delete_owned_ports(team->id);
	sem_delete_owned_sems(team->id);
	remove_images(team);
	vfs_exec_io_context(team->io_context);

	user_debug_finish_after_exec();

	// rename the team

	strlcpy(team->name, path, B_OS_NAME_LENGTH);

	// cut the path from the team name and rename the main thread, too
	threadName = strrchr(path, '/');
	if (threadName != NULL)
		threadName++;
	else
		threadName = path;
	rename_thread(thread_get_current_thread_id(), threadName);

	status = team_create_thread_start(teamArgs);
		// this one usually doesn't return...

	// sorry, we have to kill us, there is no way out anymore
	// (without any areas left and all that)
	exit_thread(status);

	// we return a status here since the signal that is sent by the
	// call above is not immediately handled
	return B_ERROR;
}


/** This is the first function to be called from the newly created
 *	main child thread.
 *	It will fill in everything what's left to do from fork_arg, and
 *	return from the parent's fork() syscall to the child.
 */

static int32
fork_team_thread_start(void *_args)
{
	struct thread *thread = thread_get_current_thread();
	struct fork_arg *forkArgs = (struct fork_arg *)_args;

	struct arch_fork_arg archArgs = forkArgs->arch_info;
		// we need a local copy of the arch dependent part

	thread->user_stack_area = forkArgs->user_stack_area;
	thread->user_stack_base = forkArgs->user_stack_base;
	thread->user_stack_size = forkArgs->user_stack_size;
	thread->user_local_storage = forkArgs->user_local_storage;
	thread->sig_block_mask = forkArgs->sig_block_mask;

	arch_thread_init_tls(thread);

	free(forkArgs);

	// set frame of the parent thread to this one, too

	arch_restore_fork_frame(&archArgs);
		// This one won't return here

	return 0;
}


static thread_id
fork_team(void)
{
	struct team *parentTeam = thread_get_current_thread()->team, *team;
	struct thread *parentThread = thread_get_current_thread();
	struct process_group *group = NULL;
	struct fork_arg *forkArgs;
	struct area_info info;
	thread_id threadID;
	cpu_status state;
	status_t status;
	int32 cookie;

	TRACE(("fork_team(): team %lx\n", parentTeam->id));

	if (parentTeam == team_get_kernel_team())
		return B_NOT_ALLOWED;

	// create a new team
	// ToDo: this is very similar to team_create_team() - maybe we can do something about it :)

	team = create_team_struct(parentTeam->name, false);
	if (team == NULL)
		return B_NO_MEMORY;

	strlcpy(team->args, parentTeam->args, sizeof(team->args));

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	hash_insert(sTeamHash, team);
	insert_team_into_parent(parentTeam, team);
	insert_team_into_group(parentTeam->group, team);
	sUsedTeams++;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	forkArgs = (struct fork_arg *)malloc(sizeof(struct fork_arg));
	if (forkArgs == NULL) {
		status = B_NO_MEMORY;
		goto err1;
	}

	// create a new io_context for this team
	team->io_context = vfs_new_io_context(parentTeam->io_context);
	if (!team->io_context) {
		status = B_NO_MEMORY;
		goto err2;
	}

	// create an address space for this team
	status = vm_create_address_space(team->id, USER_BASE, USER_SIZE, false,
		&team->address_space);
	if (status < B_OK)
		goto err3;

	// copy all areas of the team
	// ToDo: should be able to handle stack areas differently (ie. don't have them copy-on-write)
	// ToDo: all stacks of other threads than the current one could be left out

	cookie = 0;
	while (get_next_area_info(B_CURRENT_TEAM, &cookie, &info) == B_OK) {
		void *address;
		area_id area = vm_copy_area(team->address_space->id, info.name,
			&address, B_CLONE_ADDRESS, info.protection, info.area);
		if (area < B_OK) {
			status = area;
			break;
		}

		if (info.area == parentThread->user_stack_area)
			forkArgs->user_stack_area = area;
	}

	if (status < B_OK)
		goto err4;

	forkArgs->user_stack_base = parentThread->user_stack_base;
	forkArgs->user_stack_size = parentThread->user_stack_size;
	forkArgs->user_local_storage = parentThread->user_local_storage;
	forkArgs->sig_block_mask = parentThread->sig_block_mask;
	arch_store_fork_frame(&forkArgs->arch_info);

	// ToDo: copy image list

	// create a kernel thread under the context of the new team
	threadID = spawn_kernel_thread_etc(fork_team_thread_start,
		parentThread->name, parentThread->priority, forkArgs,
		team->id, team->id);
	if (threadID < 0) {
		status = threadID;
		goto err4;
	}

	// notify the debugger
	user_debug_team_created(team->id);

	resume_thread(threadID);
	return threadID;

err4:
	vm_delete_address_space(team->address_space);
err3:
	vfs_free_io_context(team->io_context);
err2:
	free(forkArgs);
err1:
	// remove the team structure from the team hash table and delete the team structure
	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	remove_team_from_group(team, &group);
	remove_team_from_parent(parentTeam, team);
	hash_remove(sTeamHash, team);

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	team_delete_process_group(group);
	delete_team_struct(team);

	return status;
}


/**	Returns if the specified \a team has any children belonging to the specified \a group.
 *	Must be called with the team lock held.
 */

static bool
has_children_in_group(struct team *parent, pid_t groupID)
{
	struct team *team;

	struct process_group *group = team_get_process_group_locked(
		parent->group->session, groupID);
	if (group == NULL)
		return false;

	for (team = group->teams; team; team = team->group_next) {
		if (team->parent == parent)
			return true;
	}

	return false;
}


/** This is the kernel backend for waitpid(). It is a bit more powerful when it comes
 *	to the reason why a thread has died than waitpid() can be.
 */

static thread_id
wait_for_child(thread_id child, uint32 flags, int32 *_reason, status_t *_returnCode)
{
	struct team *team = thread_get_current_thread()->team;
	struct death_entry death, *freeDeath = NULL;
	status_t status = B_OK;
	bool childrenExist = false;

	TRACE(("wait_for_child(child = %ld, flags = %ld)\n", child, flags));

	if (child == 0) {
		// wait for all children in the process group of the calling team
		child = -team->group_id;
	}
	if (child < 0) {
		// we need to make sure the death entries won't get deleted too soon
		atomic_add(&team->dead_children.wait_for_any, 1);
	}

	while (true) {
		sem_id waitSem = -1;

		cpu_status state = disable_interrupts();
		GRAB_THREAD_LOCK();

		if (child > 0 && !childrenExist) {
			// wait for the specified child

			struct thread *childThread = thread_get_thread_struct_locked(child);
			if (childThread != NULL) {
				// team is still running, so we would need to block
				if ((flags & WNOHANG) != 0)
					status = B_WOULD_BLOCK;

				// make sure this child is one of ours
				if (childThread->team->parent != team)
					status = ECHILD;

				childrenExist = true;
			}
		}

		RELEASE_THREAD_LOCK();

		if (status != B_OK) {
			restore_interrupts(state);
			return status;
		}

		// see if there is any death entry for us already

		GRAB_TEAM_LOCK();

		status = team_get_death_entry(team, child, &death, &freeDeath);
		if (status < B_OK) {
			// there is no matching death entry
			if (child == -1)
				childrenExist = team->children != NULL;
			else if (child < -1)
				childrenExist = has_children_in_group(team, -child);

			if (!childrenExist) {
				// there is no child we could wait for
				status = ECHILD;
			} else {
				// the children we're waiting for are still running
				status = B_WOULD_BLOCK;
			}
		}
		if (status == B_WOULD_BLOCK && (flags & WNOHANG) == 0) {
			// We need to hold the team lock when changing this counter,
			// but of course only if we really will wait later
			waitSem = team->dead_children.sem;
			team->dead_children.waiters++;
		}

		RELEASE_TEAM_LOCK();
		restore_interrupts(state);

		// we got our death entry and can return to our caller
		if (status == B_OK)
			break;
		if (status != B_WOULD_BLOCK || (flags & WNOHANG) != 0)
			goto err;

		status = acquire_sem_etc(waitSem, 1, B_CAN_INTERRUPT, 0);
		if (status == B_INTERRUPTED)
			goto err;
	}

	free(freeDeath);

	// when we got here, we have a valid death entry, and
	// already got unregistered from the team or group
	*_returnCode = death.status;
	*_reason = (death.signal << 16) | death.reason;

	return death.thread;

err:
	if (child < 0)
		atomic_add(&team->dead_children.wait_for_any, -1);

	return status;
}


/** Fills the team_info structure with information from the specified
 *	team.
 *	The team lock must be held when called.
 */

static status_t
fill_team_info(struct team *team, team_info *info, size_t size)
{
	if (size != sizeof(team_info))
		return B_BAD_VALUE;

	// ToDo: Set more informations for team_info
	memset(info, 0, size);

	info->team = team->id;
	info->thread_count = team->num_threads;
	info->image_count = count_images(team);
	//info->area_count = 
	info->debugger_nub_thread = team->debug_info.nub_thread;
	info->debugger_nub_port = team->debug_info.nub_port;
	//info->uid = 
	//info->gid = 

	strlcpy(info->args, team->args, sizeof(info->args));
	info->argc = 1;

	return B_OK;
}


//	#pragma mark - Private kernel API


status_t
team_init(kernel_args *args)
{
	struct process_session *session;
	struct process_group *group;

	// create the team hash table
	sTeamHash = hash_init(16, offsetof(struct team, next),
		&team_struct_compare, &team_struct_hash);

	sGroupHash = hash_init(16, offsetof(struct process_group, next),
		&process_group_compare, &process_group_hash);

	// create initial session and process groups

	session = create_process_session(1);
	if (session == NULL)
		panic("Could not create initial session.\n");

	group = create_process_group(1);
	if (group == NULL)
		panic("Could not create initial process group.\n");

	insert_group_into_session(session, group);

	// create the kernel team
	sKernelTeam = create_team_struct("kernel_team", true);
	if (sKernelTeam == NULL)
		panic("could not create kernel team!\n");
	strcpy(sKernelTeam->args, sKernelTeam->name);
	sKernelTeam->state = TEAM_STATE_NORMAL;

	insert_team_into_group(group, sKernelTeam);

	sKernelTeam->io_context = vfs_new_io_context(NULL);
	if (sKernelTeam->io_context == NULL)
		panic("could not create io_context for kernel team!\n");

	// stick it in the team hash
	hash_insert(sTeamHash, sKernelTeam);

	add_debugger_command("team", &dump_team_info, "list info about a particular team");
	add_debugger_command("teams", &dump_teams, "list all teams");
	return 0;
}


int32
team_max_teams(void)
{
	return sMaxTeams;
}


int32
team_used_teams(void)
{
	return sUsedTeams;
}


/** Fills the provided death entry if it's in the team.
 *	The \a child parameter follows waitpid() semantics.
 *	You need to have the team lock held when calling this function.
 */

status_t
team_get_death_entry(struct team *team, thread_id child, struct death_entry *death,
	struct death_entry **_freeDeath)
{
	struct death_entry *entry = NULL;

	// find matching death entry structure

	if (child == 0) {
		// wait for all children in the process group of the calling team
		child = -team->group_id;
	}

	while ((entry = list_get_next_item(&team->dead_children.list, entry)) != NULL) {
		if (child != -1 && entry->thread != child && entry->group_id != -child)
			continue;

		// we found one

		*death = *entry;

		// only remove the death entry if there aren't any other interested parties
		if ((child < 0 && atomic_add(&team->dead_children.wait_for_any, -1) == 1)
			|| (child > 0 && team->dead_children.wait_for_any == 0)) {
			list_remove_link(entry);
			team->dead_children.count--;
			*_freeDeath = entry;
		}

		return B_OK;
	}

	return B_ERROR;
}


/** Quick check to see if we have a valid team ID.
 */

bool
team_is_valid(team_id id)
{
	struct team *team;
	cpu_status state;

	if (id <= 0)
		return false;

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(id);

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	return team != NULL;
}


struct team *
team_get_team_struct_locked(team_id id)
{
	struct team_key key;
	key.id = id;

	return hash_lookup(sTeamHash, &key);
}


/** This searches the session of the team for the specified group ID.
 *	You must hold the team lock when you call this function.
 */

struct process_group *
team_get_process_group_locked(struct process_session *session, pid_t id)
{
	struct process_group *group;
	struct team_key key;
	key.id = id;

	group = (struct process_group *)hash_lookup(sGroupHash, &key);
	if (group != NULL && (session == NULL || session == group->session))
		return group;

	return NULL;
}


void
team_delete_process_group(struct process_group *group)
{
	if (group == NULL)
		return;

	TRACE(("team_delete_process_group(id = %ld)\n", group->id));

	// remove_group_from_session() keeps this pointer around
	// only if the session can be freed as well
	if (group->session) {
		TRACE(("team_delete_process_group(): frees session %ld\n", group->session->id));
		free(group->session);
	}

	free(group);
}


/**	Removes the specified team from the global team hash, and from its parent.
 *	It also moves all of its children up to the parent.
 *	You must hold the team lock when you call this function.
 *	If \a _freeGroup is set to a value other than \c NULL, it must be freed
 *	from the calling function.
 */

void
team_remove_team(struct team *team, struct process_group **_freeGroup)
{
	struct team *parent = team->parent;

	// remember how long this team lasted
	parent->dead_children.kernel_time += team->dead_threads_kernel_time
		+ team->dead_children.kernel_time;
	parent->dead_children.user_time += team->dead_threads_user_time
		+ team->dead_children.user_time;

	hash_remove(sTeamHash, team);
	sUsedTeams--;

	team->state = TEAM_STATE_DEATH;

	// reparent each of the team's children
	reparent_children(team);

	// remove us from our process group
	remove_team_from_group(team, _freeGroup);

	// remove us from our parent
	remove_team_from_parent(parent, team);
}


void
team_delete_team(struct team *team)
{
	team_id teamID = team->id;
	port_id debuggerPort = -1;
	cpu_status state;

	if (team->num_threads > 0) {
		// there are other threads still in this team,
		// cycle through and signal kill on each of the threads
		// ToDo: this can be optimized. There's got to be a better solution.
		struct thread *temp_thread;
		char death_sem_name[B_OS_NAME_LENGTH];
		sem_id deathSem;
		int32 threadCount;

		sprintf(death_sem_name, "team %ld death sem", teamID);
		deathSem = create_sem(0, death_sem_name);
		if (deathSem < 0)
			panic("team_delete_team: cannot init death sem for team %ld\n", teamID);

		state = disable_interrupts();
		GRAB_TEAM_LOCK();

		team->death_sem = deathSem;
		threadCount = team->num_threads;

		// If the team was being debugged, that will stop with the termination
		// of the nub thread. The team structure has already been removed from
		// the team hash table at this point, so noone can install a debugger
		// anymore. We fetch the debugger's port to send it a message at the
		// bitter end.
		GRAB_TEAM_DEBUG_INFO_LOCK(team->debug_info);

		if (team->debug_info.flags & B_TEAM_DEBUG_DEBUGGER_INSTALLED)
			debuggerPort = team->debug_info.debugger_port;

		RELEASE_TEAM_DEBUG_INFO_LOCK(team->debug_info);

		// we can safely walk the list because of the lock. no new threads can be created
		// because of the TEAM_STATE_DEATH flag on the team
		temp_thread = team->thread_list;
		while (temp_thread) {
			struct thread *next = temp_thread->team_next;

			send_signal_etc(temp_thread->id, SIGKILLTHR, B_DO_NOT_RESCHEDULE);
			temp_thread = next;
		}

		RELEASE_TEAM_LOCK();
		restore_interrupts(state);

		// wait until all threads in team are dead.
		acquire_sem_etc(team->death_sem, threadCount, 0, 0);
		delete_sem(team->death_sem);
	}

	// If someone is waiting for this team to be loaded, but it dies
	// unexpectedly before being done, we need to notify the waiting
	// thread now.

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	if (team->loading_info) {
		// there's indeed someone waiting
		struct team_loading_info *loadingInfo = team->loading_info;
		team->loading_info = NULL;

		loadingInfo->result = B_ERROR;
		loadingInfo->done = true;

		GRAB_THREAD_LOCK();

		// wake up the waiting thread
		if (loadingInfo->thread->state == B_THREAD_SUSPENDED) {
			loadingInfo->thread->state = B_THREAD_READY;
			loadingInfo->thread->next_state = B_THREAD_READY;
			scheduler_enqueue_in_run_queue(loadingInfo->thread);
		}

		RELEASE_THREAD_LOCK();
	}

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	// notify team watchers

	{
		// we're not reachable from anyone anymore at this point, so we
		// can safely access the list without any locking
		struct team_watcher *watcher;
		while ((watcher = list_remove_head_item(&team->watcher_list)) != NULL) {
			watcher->hook(teamID, watcher->data);
			free(watcher);
		}
	}

	// free team resources

	vm_delete_address_space(team->address_space);
	delete_owned_ports(teamID);
	sem_delete_owned_sems(teamID);
	remove_images(team);
	vfs_free_io_context(team->io_context);

	// ToDo: should our death_entries be moved one level up?
	delete_team_struct(team);

	// notify the debugger, that the team is gone
	user_debug_team_deleted(teamID, debuggerPort);
}


struct team *
team_get_kernel_team(void)
{
	return sKernelTeam;
}


team_id
team_get_kernel_team_id(void)
{
	if (!sKernelTeam)
		return 0;

	return sKernelTeam->id;
}


team_id
team_get_current_team_id(void)
{
	return thread_get_current_thread()->team->id;
}


status_t
team_get_address_space(team_id id, vm_address_space **_addressSpace)
{
	cpu_status state;
	struct team *team;
	status_t status;

	// ToDo: we need to do something about B_SYSTEM_TEAM vs. its real ID (1)
	if (id == 1) {
		// we're the kernel team, so we don't have to go through all
		// the hassle (locking and hash lookup)
		*_addressSpace = vm_get_kernel_address_space();
		return B_OK;
	}

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(id);
	if (team != NULL) {
		atomic_add(&team->address_space->ref_count, 1);
		*_addressSpace = team->address_space;
		status = B_OK;
	} else
		status = B_BAD_VALUE;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	return status;
}


/** Adds a hook to the team that is called as soon as this
 *	team goes away.
 *	This call might get public in the future.
 */

status_t
start_watching_team(team_id teamID, void (*hook)(team_id, void *), void *data)
{
	struct team_watcher *watcher;
	struct team *team;
	cpu_status state;

	if (hook == NULL || teamID < B_OK)
		return B_BAD_VALUE;

	watcher = malloc(sizeof(struct team_watcher));
	if (watcher == NULL)
		return B_NO_MEMORY;

	watcher->hook = hook;
	watcher->data = data;

	// find team and add watcher

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(teamID);
	if (team != NULL)
		list_add_item(&team->watcher_list, watcher);

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (team == NULL) {
		free(watcher);
		return B_BAD_TEAM_ID;
	}

	return B_OK;
}
	
	
status_t
stop_watching_team(team_id teamID, void (*hook)(team_id, void *), void *data)
{
	struct team_watcher *watcher = NULL;
	struct team *team;
	cpu_status state;

	if (hook == NULL || teamID < B_OK)
		return B_BAD_VALUE;

	// find team and remove watcher (if present)

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(teamID);
	if (team != NULL) {
		// search for watcher
		while ((watcher = list_get_next_item(&team->watcher_list, watcher)) != NULL) {
			if (watcher->hook == hook && watcher->data == data) {
				// got it!
				list_remove_item(&team->watcher_list, watcher);
				break;
			}
		}
	}

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (watcher == NULL)
		return B_ENTRY_NOT_FOUND;

	free(watcher);
	return B_OK;
}


//	#pragma mark - Public kernel API


thread_id
load_image(int32 argCount, const char **args, const char **env)
{
	int32 envCount = 0;

	// count env variables
	while (env && env[envCount] != NULL)
		envCount++;

	return load_image_etc(argCount, (char * const *)args, envCount,
		(char * const *)env, B_NORMAL_PRIORITY, B_WAIT_TILL_LOADED, true);
}


status_t
wait_for_team(team_id id, status_t *_returnCode)
{
	struct team *team;
	thread_id thread;
	cpu_status state;

	// find main thread and wait for that

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(id);
	if (team != NULL && team->main_thread != NULL)
		thread = team->main_thread->id;
	else
		thread = B_BAD_THREAD_ID;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (thread < 0)
		return thread;

	return wait_for_thread(thread, _returnCode);
}


status_t
kill_team(team_id id)
{
	status_t status = B_OK;
	thread_id threadID = -1;
	struct team *team;
	cpu_status state;

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(id);
	if (team != NULL) {
		if (team != sKernelTeam) {
			threadID = team->id;
				// the team ID is the same as the ID of its main thread
		} else
			status = B_NOT_ALLOWED;
	} else
		status = B_BAD_THREAD_ID;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (status < B_OK)
		return status;

	// just kill the main thread in the team. The cleanup code there will
	// take care of the team
	return kill_thread(threadID);
}


status_t
_get_team_info(team_id id, team_info *info, size_t size)
{
	cpu_status state;
	status_t status = B_OK;
	struct team *team;

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	if (id == B_CURRENT_TEAM)
		team = thread_get_current_thread()->team;
	else
		team = team_get_team_struct_locked(id);

	if (team == NULL) {
		status = B_BAD_TEAM_ID;
		goto err;
	}

	status = fill_team_info(team, info, size);

err:
	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	return status;
}


status_t
_get_next_team_info(int32 *cookie, team_info *info, size_t size)
{
	status_t status = B_BAD_TEAM_ID;
	struct team *team = NULL;
	int32 slot = *cookie;
	team_id lastTeamID;
	cpu_status state;

	if (slot < 1)
		slot = 1;

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	lastTeamID = peek_next_thread_id();
	if (slot >= lastTeamID)
		goto err;

	// get next valid team
	while (slot < lastTeamID && !(team = team_get_team_struct_locked(slot)))
		slot++;

	if (team) {
		status = fill_team_info(team, info, size);
		*cookie = ++slot;
	}

err:
	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	return status;
}


status_t
_get_team_usage_info(team_id id, int32 who, team_usage_info *info, size_t size)
{
	bigtime_t kernelTime = 0, userTime = 0;
	status_t status = B_OK;
	struct team *team;
	cpu_status state;

	if (size != sizeof(team_usage_info)
		|| (who != B_TEAM_USAGE_SELF && who != B_TEAM_USAGE_CHILDREN))
		return B_BAD_VALUE;

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	if (id == B_CURRENT_TEAM)
		team = thread_get_current_thread()->team;
	else
		team = team_get_team_struct_locked(id);

	if (team == NULL) {
		status = B_BAD_TEAM_ID;
		goto out;
	}

	switch (who) {
		case B_TEAM_USAGE_SELF:
		{
			struct thread *thread = team->thread_list;

			for (; thread != NULL; thread = thread->team_next) {
				kernelTime += thread->kernel_time;
				userTime += thread->user_time;
			}

			kernelTime += team->dead_threads_kernel_time;
			userTime += team->dead_threads_user_time;
			break;
		}

		case B_TEAM_USAGE_CHILDREN:
		{
			struct team *child = team->children;
			for (; child != NULL; child = child->siblings_next) {
				struct thread *thread = team->thread_list;

				for (; thread != NULL; thread = thread->team_next) {
					kernelTime += thread->kernel_time;
					userTime += thread->user_time;
				}

				kernelTime += child->dead_threads_kernel_time;
				userTime += child->dead_threads_user_time;
			}

			kernelTime += team->dead_children.kernel_time;
			userTime += team->dead_children.user_time;
			break;
		}
	}

out:
	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (status == B_OK) {
		info->kernel_time = kernelTime;
		info->user_time = userTime;
	}

	return status;
}


pid_t
getpid(void)
{
	return thread_get_current_thread()->team->id;
}


pid_t
getppid(void)
{
	struct team *team = thread_get_current_thread()->team;
	cpu_status state;
	pid_t parent;

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	parent = team->parent->id;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	return parent;
}


pid_t
getpgid(pid_t process)
{
	struct thread *thread;
	pid_t result = -1;
	cpu_status state;

	if (process == 0)
		process = thread_get_current_thread()->team->id;

	state = disable_interrupts();
	GRAB_THREAD_LOCK();

	thread = thread_get_thread_struct_locked(process);
	if (thread != NULL)
		result = thread->team->group_id;

	RELEASE_THREAD_LOCK();
	restore_interrupts(state);

	return thread != NULL ? result : B_BAD_VALUE;
}


pid_t
getsid(pid_t process)
{
	struct thread *thread;
	pid_t result = -1;
	cpu_status state;

	if (process == 0)
		process = thread_get_current_thread()->team->id;

	state = disable_interrupts();
	GRAB_THREAD_LOCK();

	thread = thread_get_thread_struct_locked(process);
	if (thread != NULL)
		result = thread->team->session_id;

	RELEASE_THREAD_LOCK();
	restore_interrupts(state);

	return thread != NULL ? result : B_BAD_VALUE;
}


//	#pragma mark - User syscalls


status_t
_user_exec(const char *userPath, int32 argCount, char * const *userArgs,
	int32 envCount, char * const *userEnvironment)
{
	char path[B_PATH_NAME_LENGTH];

	if (argCount < 1)
		return B_BAD_VALUE;

	if (!IS_USER_ADDRESS(userPath) || !IS_USER_ADDRESS(userArgs)
		|| !IS_USER_ADDRESS(userEnvironment)
		|| user_strlcpy(path, userPath, sizeof(path)) < B_OK)
		return B_BAD_ADDRESS;

	return exec_team(path, argCount, userArgs, envCount, userEnvironment);
		// this one only returns in case of error
}


thread_id
_user_fork(void)
{
	return fork_team();
}


thread_id
_user_wait_for_child(thread_id child, uint32 flags, int32 *_userReason, status_t *_userReturnCode)
{
	status_t returnCode;
	int32 reason;
	thread_id deadChild;

	if ((_userReason != NULL && !IS_USER_ADDRESS(_userReason))
		|| (_userReturnCode != NULL && !IS_USER_ADDRESS(_userReturnCode)))
		return B_BAD_ADDRESS;

	deadChild = wait_for_child(child, flags, &reason, &returnCode);

	if (deadChild >= B_OK) {
		// copy result data on successful completion
		if ((_userReason != NULL && user_memcpy(_userReason, &reason, sizeof(int32)) < B_OK)
			|| (_userReturnCode != NULL && user_memcpy(_userReturnCode, &returnCode, sizeof(status_t)) < B_OK))
			return B_BAD_ADDRESS;
	}

	return deadChild;
}


pid_t
_user_process_info(pid_t process, int32 which)
{
	// we only allow to return the parent of the current process
	if (which == PARENT_ID
		&& process != 0 && process != thread_get_current_thread()->team->id)
		return B_BAD_VALUE;

	switch (which) {
		case SESSION_ID:
			return getsid(process);
		case GROUP_ID:
			return getpgid(process);
		case PARENT_ID:
			return getppid();
	}

	return B_BAD_VALUE;
}


pid_t
_user_setpgid(pid_t processID, pid_t groupID)
{
	struct thread *thread = thread_get_current_thread();
	struct team *currentTeam = thread->team;
	struct process_group *group = NULL, *freeGroup = NULL;
	struct team *team;
	cpu_status state;
	team_id teamID = -1;
	status_t status = B_OK;

	// TODO: we might want to notify waiting wait_for_child() threads in case
	//	they wait for children of the former process group ID (see wait_test_4.cpp)

	if (groupID < 0)
		return B_BAD_VALUE;

	if (processID == 0)
		processID = currentTeam->id;

	if (processID == currentTeam->id) {
		// we set our own group
		teamID = currentTeam->id;

		// we must not change our process group ID if we're a group leader
		if (is_process_group_leader(currentTeam)) {
			// if the group ID was not specified, we just return the
			// process ID as we already are a process group leader
			if (groupID == 0 || groupID == processID)
				return processID;

			return B_NOT_ALLOWED;
		}

		status = B_OK;
	} else {
		state = disable_interrupts();
		GRAB_THREAD_LOCK();

		thread = thread_get_thread_struct_locked(processID);

		// the thread must be the team's main thread, as that
		// determines its process ID
		if (thread != NULL && thread == thread->team->main_thread) {
			// check if the thread is in a child team of the calling team and
			// if it's already a process group leader and in the same session
			if (thread->team->parent != currentTeam
				|| is_process_group_leader(thread->team)
				|| thread->team->session_id != currentTeam->session_id)
				status = B_NOT_ALLOWED;
			else
				teamID = thread->team->id;
		} else
			status = B_BAD_THREAD_ID;

		RELEASE_THREAD_LOCK();
		restore_interrupts(state);
	}

	if (status != B_OK)
		return status;

	// if the group ID is not specified, a new group should be created
	if (groupID == 0)
		groupID = processID;

	if (groupID == processID) {
		// We need to create a new process group for this team
		group = create_process_group(groupID);
		if (group == NULL)
			return B_NO_MEMORY;
	}

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	team = team_get_team_struct_locked(teamID);
	if (team != NULL) {
		if (processID == groupID) {
			// we created a new process group, let us insert it into the team's session
			insert_group_into_session(team->group->session, group);
			remove_team_from_group(team, &freeGroup);
			insert_team_into_group(group, team);
		} else {
			// check if this team can have the group ID; there must be one matching
			// process ID in the team's session

			struct process_group *group =
				team_get_process_group_locked(team->group->session, groupID);
			if (group) {
				// we got a group, let's move the team there
				remove_team_from_group(team, &freeGroup);
				insert_team_into_group(group, team);
			} else
				status = B_NOT_ALLOWED;
		}
	} else
		status = B_NOT_ALLOWED;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (status != B_OK && group != NULL) {
		// in case of error, the group hasn't been added into the hash
		team_delete_process_group(group);
	}

	team_delete_process_group(freeGroup);

	return status == B_OK ? groupID : status;
}


pid_t
_user_setsid(void)
{
	struct team *team = thread_get_current_thread()->team;
	struct process_session *session;
	struct process_group *group, *freeGroup = NULL;
	cpu_status state;
	bool failed = false;

	// the team must not already be a process group leader
	if (is_process_group_leader(team))
		return B_NOT_ALLOWED;

	group = create_process_group(team->id);
	if (group == NULL)
		return B_NO_MEMORY;

	session = create_process_session(group->id);
	if (session == NULL) {
		team_delete_process_group(group);
		return B_NO_MEMORY;
	}

	state = disable_interrupts();
	GRAB_TEAM_LOCK();

	// this may have changed since the check above
	if (!is_process_group_leader(team)) {
		remove_team_from_group(team, &freeGroup);

		insert_group_into_session(session, group);
		insert_team_into_group(group, team);
	} else
		failed = true;

	RELEASE_TEAM_LOCK();
	restore_interrupts(state);

	if (failed) {
		team_delete_process_group(group);
		free(session);
		return B_NOT_ALLOWED;
	} else
		team_delete_process_group(freeGroup);

	return team->group_id;
}


status_t
_user_wait_for_team(team_id id, status_t *_userReturnCode)
{
	status_t returnCode;
	status_t status;

	if (_userReturnCode != NULL && !IS_USER_ADDRESS(_userReturnCode))
		return B_BAD_ADDRESS;

	status = wait_for_team(id, &returnCode);
	if (status >= B_OK && _userReturnCode != NULL) {
		if (user_memcpy(_userReturnCode, &returnCode, sizeof(returnCode)) < B_OK)
			return B_BAD_ADDRESS;
	}

	return status;
}


team_id
_user_load_image(int32 argCount, const char **userArgs, int32 envCount,
	const char **userEnv, int32 priority, uint32 flags)
{
	TRACE(("_user_load_image_etc: argc = %ld\n", argCount));

	if (argCount < 1 || userArgs == NULL || userEnv == NULL)
		return B_BAD_VALUE;

	if (!IS_USER_ADDRESS(userArgs) || !IS_USER_ADDRESS(userEnv))
		return B_BAD_ADDRESS;

	return load_image_etc(argCount, (char * const *)userArgs,
		envCount, (char * const *)userEnv, priority, flags, false);
}


void
_user_exit_team(status_t returnValue)
{
	struct thread *thread = thread_get_current_thread();

	thread->exit.status = returnValue;
	thread->exit.reason = THREAD_RETURN_EXIT;

	send_signal(thread->id, SIGKILL);
}


status_t
_user_kill_team(team_id team)
{
	return kill_team(team);
}


status_t
_user_get_team_info(team_id id, team_info *userInfo)
{
	status_t status;
	team_info info;

	if (!IS_USER_ADDRESS(userInfo))
		return B_BAD_ADDRESS;	

	status = _get_team_info(id, &info, sizeof(team_info));
	if (status == B_OK) {
		if (user_memcpy(userInfo, &info, sizeof(team_info)) < B_OK)
			return B_BAD_ADDRESS;
	}

	return status;
}


status_t
_user_get_next_team_info(int32 *userCookie, team_info *userInfo)
{
	status_t status;
	team_info info;
	int32 cookie;

	if (!IS_USER_ADDRESS(userCookie)
		|| !IS_USER_ADDRESS(userInfo)
		|| user_memcpy(&cookie, userCookie, sizeof(int32)) < B_OK)
		return B_BAD_ADDRESS;

	status = _get_next_team_info(&cookie, &info, sizeof(team_info));
	if (status != B_OK)
		return status;

	if (user_memcpy(userCookie, &cookie, sizeof(int32)) < B_OK
		|| user_memcpy(userInfo, &info, sizeof(team_info)) < B_OK)
		return B_BAD_ADDRESS;

	return status;
}


team_id
_user_get_current_team(void)
{
	return team_get_current_team_id();
}


status_t
_user_get_team_usage_info(team_id team, int32 who, team_usage_info *userInfo, size_t size)
{
	team_usage_info info;
	status_t status;

	if (!IS_USER_ADDRESS(userInfo))
		return B_BAD_ADDRESS;

	status = _get_team_usage_info(team, who, &info, size);
	if (status != B_OK)
		return status;

	if (user_memcpy(userInfo, &info, size) < B_OK)
		return B_BAD_ADDRESS;

	return status;
}