Process groups

Process groups. More...

Collaboration diagram for Process groups:

Detailed Description

Process groups.

Process groups allow related processes to be grouped together, enabling operations such as sending notes to all processes within a group.

As an example, if a user wishes to terminate a shell they most likely additionally want to terminate all child processes started by that shell. By placing all such processes in the same group, a single "terminate" note can be sent to the entire group, effectively terminating all related processes.

Data Structures
struct	group_entry_t
	Group entry structure. More...
struct	group_t
	Process group structure. More...

Functions
void	group_entry_init (group_entry_t *entry)
	Initializes a group entry.
void	group_entry_deinit (group_entry_t *entry)
	Deinitializes a group entry.
uint64_t	group_add (gid_t gid, group_entry_t *entry)
	Adds a process to a group.
void	group_remove (group_entry_t *entry)
	Removes a process from its group.
gid_t	group_get_id (group_entry_t *entry)
	Gets the ID of the group of the specified entry.
uint64_t	group_send_note (group_entry_t *entry, const char *note)
	Sends a note to all processes in the group of the specified entry.

Function Documentation

group_entry_init()

void group_entry_init

(

group_entry_t *

entry

)

Initializes a group entry.

Parameters

entry

The group entry to initialize.

Definition at line 14 of file group.c.

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group_entry_deinit()

void group_entry_deinit

(

group_entry_t *

entry

)

Deinitializes a group entry.

Parameters

entry

The group entry to deinitialize.

Definition at line 20 of file group.c.

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group_add()

uint64_t group_add	(	gid_t	gid,
		group_entry_t *	entry
	)

Adds a process to a group.

Parameters

gid	The group ID to add the process to, or GID_NONE to create a new group.
entry	The group entry of the process to add to the group.

Returns

On success, 0. On failure, ERR and errno is set to:

• EINVAL: Invalid parameters.
• ENOENT: The specified group does not exist.
• EBUSY: The entry is already part of a group.
• ENOMEM: Out of memory.

Definition at line 25 of file group.c.

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group_remove()

void group_remove

(

group_entry_t *

entry

)

Removes a process from its group.

If the group becomes empty after removing the process, it will be freed.

Parameters

entry

The group entry of the process to remove from its group, or NULL for no-op.

Definition at line 73 of file group.c.

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group_get_id()

gid_t group_get_id

(

group_entry_t *

entry

)

Gets the ID of the group of the specified entry.

Parameters

entry

The group entry to get the group ID from.

Returns

The group ID or GID_NONE if the entry is not part of a group.

Definition at line 98 of file group.c.

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group_send_note()

uint64_t group_send_note	(	group_entry_t *	entry,
		const char *	note
	)

Sends a note to all processes in the group of the specified entry.

Parameters

entry	The entry within the group to send the note to.
note	The note string to send.

Returns

On success, 0. On failure, ERR and errno is set to:

• EINVAL: Invalid parameters.
• Other values from thread_send_note().

Definition at line 115 of file group.c.

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