* Introduced ref-counting for the I/O contexts.

* The I/O context related vfs_*() functions have io_context* instead of void*
  parameters/return values, now.
* vfs_new_io_context(): Lock the parent I/O context before getting its table
  size. Otherwise the table size could change until we do.
* vfs_resize_fd_table(): Fixed use of MutexLocker. We created only a temporary
  object, not one with function scope.
* Renamed load_image_etc() to load_image_internal() and added a parameter for
  specifying the parent team of the one to create.
* Introduced a kernel private load_image_etc() with a few more arguments than
  load_image().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29375 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/team.h

@@ -14,8 +14,6 @@ extern "C" {
 #endif
 
 status_t team_init(struct kernel_args *args);
-team_id team_create_team(const char *path, const char *name, char **args,
-			int argc, char **envp, int envc, int priority);
 status_t wait_for_team(team_id id, status_t *returnCode);
 void team_remove_team(struct team *team);
 void team_delete_team(struct team *team);
@@ -36,6 +34,9 @@ struct team *team_get_team_struct_locked(team_id id);
 int32 team_max_teams(void);
 int32 team_used_teams(void);
 
+thread_id load_image_etc(int32 argCount, const char* const* args,
+	const char* const* env, int32 priority, team_id parentID, uint32 flags);
+
 void team_set_job_control_state(struct team* team, job_control_state newState,
 			int signal, bool threadsLocked);
 void team_set_controlling_tty(int32 index);

headers/private/kernel/thread_types.h

@@ -54,6 +54,7 @@ typedef enum job_control_state {
 
 
 struct image;					// defined in image.c
+struct io_context;
 struct realtime_sem_context;	// defined in realtime_sem.cpp
 struct select_info;
 struct user_thread;				// defined in libroot/user_thread.h
@@ -172,7 +173,7 @@ struct team {
 	int				num_threads;	// number of threads in this team
 	int				state;			// current team state, see above
 	int32			flags;
-	void			*io_context;
+	struct io_context *io_context;
 	struct realtime_sem_context	*realtime_sem_context;
 	struct xsi_sem_context *xsi_sem_context;
 	sem_id			death_sem;		// semaphore to wait on for dying threads

headers/private/kernel/usergroup.h

@@ -21,6 +21,8 @@ extern "C" {
 
 void		inherit_parent_user_and_group(struct team* team,
 				struct team* parent);
+void		inherit_parent_user_and_group_locked(struct team* team,
+				struct team* parent);
 status_t	update_set_id_user_and_group(struct team* team, const char* file);
 
 // syscalls

headers/private/kernel/vfs.h

@@ -46,6 +46,7 @@ typedef struct io_context {
 	struct vnode *root;
 	struct vnode *cwd;
 	mutex		io_mutex;
+	int32		ref_count;
 	uint32		table_size;
 	uint32		num_used_fds;
 	struct file_descriptor **fds;
@@ -69,9 +70,10 @@ extern "C" {
 status_t vfs_init(struct kernel_args *args);
 status_t vfs_bootstrap_file_systems(void);
 void vfs_mount_boot_file_system(struct kernel_args *args);
-void vfs_exec_io_context(void *context);
-void *vfs_new_io_context(void *parentContext);
-status_t vfs_free_io_context(void *context);
+void vfs_exec_io_context(io_context *context);
+io_context *vfs_new_io_context(io_context *parentContext);
+void vfs_get_io_context(io_context *context);
+void vfs_put_io_context(io_context *context);
 
 struct rlimit;
 int vfs_getrlimit(int resource, struct rlimit * rlp);

src/system/kernel/fs/vfs.cpp

@@ -4595,9 +4595,8 @@ vfs_unlock_vnode_if_locked(struct file_descriptor* descriptor)
 	have the O_CLOEXEC flag set.
 */
 void
-vfs_exec_io_context(void* _context)
+vfs_exec_io_context(io_context* context)
 {
-	struct io_context* context = (struct io_context*)_context;
 	uint32 i;
 
 	for (i = 0; i < context->table_size; i++) {
@@ -4626,23 +4625,24 @@ vfs_exec_io_context(void* _context)
 /*! Sets up a new io_control structure, and inherits the properties
 	of the parent io_control if it is given.
 */
-void*
-vfs_new_io_context(void* _parentContext)
+io_context*
+vfs_new_io_context(io_context* parentContext)
 {
 	size_t tableSize;
 	struct io_context* context;
-	struct io_context* parentContext;
 
 	context = (io_context*)malloc(sizeof(struct io_context));
 	if (context == NULL)
 		return NULL;
 
 	memset(context, 0, sizeof(struct io_context));
+	context->ref_count = 1;
 
-	parentContext = (struct io_context*)_parentContext;
-	if (parentContext)
+	MutexLocker parentLocker;
+	if (parentContext) {
+		parentLocker.SetTo(parentContext->io_mutex, false);
 		tableSize = parentContext->table_size;
-	else
+	} else
 		tableSize = DEFAULT_FD_TABLE_SIZE;
 
 	// allocate space for FDs and their close-on-exec flag
@@ -4669,8 +4669,6 @@ vfs_new_io_context(void* _parentContext)
 	if (parentContext) {
 		size_t i;
 
-		mutex_lock(&parentContext->io_mutex);
-
 		mutex_lock(&sIOContextRootLock);
 		context->root = parentContext->root;
 		if (context->root)
@@ -4695,7 +4693,7 @@ vfs_new_io_context(void* _parentContext)
 			}
 		}
 
-		mutex_unlock(&parentContext->io_mutex);
+		parentLocker.Unlock();
 	} else {
 		context->root = sRoot;
 		context->cwd = sRoot;
@@ -4716,10 +4714,9 @@ vfs_new_io_context(void* _parentContext)
 }
 
 
-status_t
-vfs_free_io_context(void* _ioContext)
+static status_t
+vfs_free_io_context(io_context* context)
 {
-	struct io_context* context = (struct io_context*)_ioContext;
 	uint32 i;
 
 	if (context->root)
@@ -4747,13 +4744,26 @@ vfs_free_io_context(void* _ioContext)
 }
 
 
+void vfs_get_io_context(io_context *context)
+{
+	atomic_add(&context->ref_count, 1);
+}
+
+
+void vfs_put_io_context(io_context *context)
+{
+	if (atomic_add(&context->ref_count, -1) == 1)
+		vfs_free_io_context(context);
+}
+
+
 static status_t
 vfs_resize_fd_table(struct io_context* context, const int newSize)
 {
 	if (newSize <= 0 || newSize > MAX_FD_TABLE_SIZE)
 		return EINVAL;
 
-	MutexLocker(context->io_mutex);
+	MutexLocker _(context->io_mutex);
 
 	int oldSize = context->table_size;
 	int oldCloseOnExitBitmapSize = (oldSize + 7) / 8;

src/system/kernel/team.cpp

@@ -1085,37 +1085,33 @@ team_create_thread_start(void *args)
 }
 
 
-/*!	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(char**& _flatArgs, size_t flatArgsSize, int32 argCount,
-	int32 envCount, int32 priority, uint32 flags, port_id errorPort,
-	uint32 errorToken)
+load_image_internal(char**& _flatArgs, size_t flatArgsSize, int32 argCount,
+	int32 envCount, int32 priority, team_id parentID, uint32 flags,
+	port_id errorPort, uint32 errorToken)
 {
 	char** flatArgs = _flatArgs;
-	struct team *team, *parent;
+	struct team *team;
 	const char *threadName;
 	thread_id thread;
 	status_t status;
 	cpu_status state;
 	struct team_arg *teamArgs;
 	struct team_loading_info loadingInfo;
+	io_context* parentIOContext = NULL;
 
 	if (flatArgs == NULL || argCount == 0)
 		return B_BAD_VALUE;
 
 	const char* path = flatArgs[0];
 
-	TRACE(("load_image_etc: name '%s', args = %p, argCount = %ld\n",
+	TRACE(("load_image_internal: name '%s', args = %p, argCount = %ld\n",
 		path, flatArgs, argCount));
 
 	team = create_team_struct(path, 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;
@@ -1123,21 +1119,38 @@ load_image_etc(char**& _flatArgs, size_t flatArgsSize, int32 argCount,
 		team->loading_info = &loadingInfo;
 	}
 
-	// Inherit the parent's user/group, but also check the executable's
-	// set-user/group-id permission
-	inherit_parent_user_and_group(team, parent);
-	update_set_id_user_and_group(team, path);
+ 	InterruptsSpinLocker teamLocker(gTeamSpinlock);
 
-	state = disable_interrupts();
-	GRAB_TEAM_LOCK();
+	// get the parent team
+	struct team* parent;
+
+	if (parentID == B_CURRENT_TEAM)
+		parent = thread_get_current_thread()->team;
+	else
+		parent = team_get_team_struct_locked(parentID);
+
+	if (parent == NULL) {
+		teamLocker.Unlock();
+		status = B_BAD_TEAM_ID;
+		goto err0;
+	}
+
+	// inherit the parent's user/group
+	inherit_parent_user_and_group_locked(team, parent);
 
 	hash_insert(sTeamHash, team);
 	insert_team_into_parent(parent, team);
 	insert_team_into_group(parent->group, team);
 	sUsedTeams++;
 
-	RELEASE_TEAM_LOCK();
-	restore_interrupts(state);
+	// get a reference to the parent's I/O context -- we need it to create ours
+	parentIOContext = parent->io_context;
+	vfs_get_io_context(parentIOContext);
+
+	teamLocker.Unlock();
+
+	// check the executable's set-user/group-id permission
+	update_set_id_user_and_group(team, path);
 
 	status = create_team_arg(&teamArgs, path, flatArgs, flatArgsSize, argCount,
 		envCount, errorPort, errorToken);
@@ -1149,12 +1162,16 @@ load_image_etc(char**& _flatArgs, size_t flatArgsSize, int32 argCount,
 		// args are owned by the team_arg structure now
 
 	// create a new io_context for this team
-	team->io_context = vfs_new_io_context(parent->io_context);
+	team->io_context = vfs_new_io_context(parentIOContext);
 	if (!team->io_context) {
 		status = B_NO_MEMORY;
 		goto err2;
 	}
 
+	// We don't need the parent's I/O context any longer.
+	vfs_put_io_context(parentIOContext);
+	parentIOContext = NULL;
+
 	// remove any fds that have the CLOEXEC flag set (emulating BeOS behaviour)
 	vfs_exec_io_context(team->io_context);
 
@@ -1229,21 +1246,25 @@ err5:
 err4:
 	vm_put_address_space(team->address_space);
 err3:
-	vfs_free_io_context(team->io_context);
+	vfs_put_io_context(team->io_context);
 err2:
 	free_team_arg(teamArgs);
 err1:
+	if (parentIOContext != NULL)
+		vfs_put_io_context(parentIOContext);
+
 	// 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);
-	remove_team_from_parent(parent, team);
+	remove_team_from_parent(team->parent, team);
 	hash_remove(sTeamHash, team);
 
 	RELEASE_TEAM_LOCK();
 	restore_interrupts(state);
 
+err0:
 	delete_team_struct(team);
 
 	return status;
@@ -1431,7 +1452,8 @@ fork_team(void)
 		return B_NOT_ALLOWED;
 
 	// create a new team
-	// ToDo: this is very similar to team_create_team() - maybe we can do something about it :)
+	// TODO: this is very similar to load_image_internal() - maybe we can do
+	// something about it :)
 
 	team = create_team_struct(parentTeam->name, false);
 	if (team == NULL)
@@ -1562,7 +1584,7 @@ err4:
 err3:
 	delete_realtime_sem_context(team->realtime_sem_context);
 err25:
-	vfs_free_io_context(team->io_context);
+	vfs_put_io_context(team->io_context);
 err2:
 	free(forkArgs);
 err1:
@@ -2354,7 +2376,7 @@ team_delete_team(struct team *team)
 
 	// free team resources
 
-	vfs_free_io_context(team->io_context);
+	vfs_put_io_context(team->io_context);
 	delete_realtime_sem_context(team->realtime_sem_context);
 	xsi_sem_undo(team);
 	delete_owned_ports(teamID);
@@ -2638,6 +2660,15 @@ team_free_user_thread(struct thread* thread)
 
 thread_id
 load_image(int32 argCount, const char **args, const char **env)
+{
+	return load_image_etc(argCount, args, env, B_NORMAL_PRIORITY,
+		B_CURRENT_TEAM, B_WAIT_TILL_LOADED);
+}
+
+
+thread_id
+load_image_etc(int32 argCount, const char* const* args,
+	const char* const* env, int32 priority, team_id parentID, uint32 flags)
 {
 	// we need to flatten the args and environment
 
@@ -2685,11 +2716,11 @@ load_image(int32 argCount, const char **args, const char **env)
 
 	*slot++ = NULL;
 
-	thread_id thread = load_image_etc(flatArgs, size, argCount, envCount,
-		B_NORMAL_PRIORITY, B_WAIT_TILL_LOADED, -1, 0);
+	thread_id thread = load_image_internal(flatArgs, size, argCount, envCount,
+		B_NORMAL_PRIORITY, parentID, B_WAIT_TILL_LOADED, -1, 0);
 
 	free(flatArgs);
-		// load_image_etc() unset our variable if it took over ownership
+		// load_image_internal() unset our variable if it took over ownership
 
 	return thread;
 }
@@ -3277,7 +3308,7 @@ _user_load_image(const char* const* userFlatArgs, size_t flatArgsSize,
 	int32 argCount, int32 envCount, int32 priority, uint32 flags,
 	port_id errorPort, uint32 errorToken)
 {
-	TRACE(("_user_load_image_etc: argc = %ld\n", argCount));
+	TRACE(("_user_load_image: argc = %ld\n", argCount));
 
 	if (argCount < 1)
 		return B_BAD_VALUE;
@@ -3289,11 +3320,12 @@ _user_load_image(const char* const* userFlatArgs, size_t flatArgsSize,
 	if (error != B_OK)
 		return error;
 
-	thread_id thread = load_image_etc(flatArgs, _ALIGN(flatArgsSize), argCount,
-		envCount, priority, flags, errorPort, errorToken);
+	thread_id thread = load_image_internal(flatArgs, _ALIGN(flatArgsSize),
+		argCount, envCount, priority, B_CURRENT_TEAM, flags, errorPort,
+		errorToken);
 
 	free(flatArgs);
-		// load_image_etc() unset our variable if it took over ownership
+		// load_image_internal() unset our variable if it took over ownership
 
 	return thread;
 }

src/system/kernel/usergroup.cpp

@@ -243,10 +243,8 @@ common_setgroups(int groupCount, const gid_t* groupList, bool kernel)
 
 
 void
-inherit_parent_user_and_group(struct team* team, struct team* parent)
+inherit_parent_user_and_group_locked(struct team* team, struct team* parent)
 {
-	InterruptsSpinLocker _(gTeamSpinlock);
-
 	team->saved_set_uid = parent->saved_set_uid;
 	team->real_uid = parent->real_uid;
 	team->effective_uid = parent->effective_uid;
@@ -260,6 +258,14 @@ inherit_parent_user_and_group(struct team* team, struct team* parent)
 }
 
 
+void
+inherit_parent_user_and_group(struct team* team, struct team* parent)
+{
+	InterruptsSpinLocker _(gTeamSpinlock);
+	inherit_parent_user_and_group_locked(team, parent);
+}
+
+
 status_t
 update_set_id_user_and_group(struct team* team, const char* file)
 {