Process Subsystem

Process management. More...

Collaboration diagram for Process Subsystem:

Detailed Description

Process management.

Processes store the shared resources for threads of execution, for example the address space and open files.

Modules
	Environment
	Environment variables.
	Process groups
	Process groups.
	Process reaper
	Process reaper for delayed process freeing.

Data Structures
struct	process_threads_t
	Represents the threads in a process. More...
struct	process_status_t
	Process exit status structure. More...
struct	process_t
	Process structure. More...

Macros
#define	PROCESS_STATUS_MAX   256
	Maximum length of a process exit status.
#define	PROCESS_RCU_THREAD_FOR_EACH(thread, process)   LIST_FOR_EACH(thread, &(process)->threads.list, processEntry)
	Macro to iterate over all threads in a process.
#define	PROCESS_RCU_FOR_EACH(process)   LIST_FOR_EACH(process, &_processes, entry)
	Macro to iterate over all processes.

Enumerations
enum	process_flags_t { PROCESS_NONE = 0 , PROCESS_DYING = 1 << 0 , PROCESS_SUSPENDED = 1 << 1 }
	Process flags enum. More...

Functions
process_t *	process_new (priority_t priority, group_member_t *group, namespace_t *ns)
	Allocates and initializes a new process.
static process_t *	process_current (void)
	Retrieves the process of the currently running thread.
static process_t *	process_current_unsafe (void)
	Retrieves the process of the currently running thread without disabling interrupts.
process_t *	process_get (pid_t id)
	Gets a process by its ID.
namespace_t *	process_get_ns (process_t *process)
	Gets the namespace of a process.
void	process_set_ns (process_t *process, namespace_t *ns)
	Sets the namespace of a process.
void	process_kill (process_t *process, const char *status)
	Kills a process, pushing it to the reaper.
void	process_remove (process_t *process)
	Removes a process from the system.
static thread_t *	process_rcu_first_thread (process_t *process)
	Gets the first thread of a process.
static uint64_t	process_rcu_thread_count (process_t *process)
	Gets the amount of threads in a process.
uint64_t	process_set_cmdline (process_t *process, char **argv, uint64_t argc)
	Sets the command line arguments for a process.
bool	process_has_thread (process_t *process, tid_t tid)
	Checks if a process has a thread with the specified thread ID.
process_t *	process_get_kernel (void)
	Gets the kernel process.

Variables
list_t	_processes
	Global list of all processes.

Macro Definition Documentation

PROCESS_STATUS_MAX

#define PROCESS_STATUS_MAX   256

Maximum length of a process exit status.

Definition at line 59 of file process.h.

PROCESS_RCU_THREAD_FOR_EACH

#define PROCESS_RCU_THREAD_FOR_EACH	(		thread,
			process
	)		LIST_FOR_EACH(thread, &(process)->threads.list, processEntry)

Macro to iterate over all threads in a process.

Warning

Must be used within a RCU read-side critical section.

Parameters

thread	Loop variable, a pointer to thread_t.
process	The process to iterate the threads of.

Definition at line 232 of file process.h.

PROCESS_RCU_FOR_EACH

#define PROCESS_RCU_FOR_EACH

(

process

)

LIST_FOR_EACH(process, &_processes, entry)

Macro to iterate over all processes.

Warning

Must be used within a RCU read-side critical section.

Parameters

process

Loop variable, a pointer to process_t.

Definition at line 241 of file process.h.

Enumeration Type Documentation

process_flags_t

enum process_flags_t

Process flags enum.

Enumerator
PROCESS_NONE
PROCESS_DYING
PROCESS_SUSPENDED

Definition at line 37 of file process.h.

Function Documentation

process_new()

process_t * process_new	(	priority_t	priority,
		group_member_t *	group,
		namespace_t *	ns
	)

Allocates and initializes a new process.

It is the responsibility of the caller to UNREF() the returned process.

Parameters

priority	The priority of the new process.
group	A member of the group to add the new process to, or NULL to create a new group for the process.
ns	The namespace to use for the new process.

Returns

On success, the newly created process. On failure, NULL and errno is set.

Definition at line 125 of file process.c.

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process_current()

static process_t * process_current ( void  )

inlinestatic

Retrieves the process of the currently running thread.

Note

Will not increment the reference count of the returned process, as we consider the currently running thread to always be referencing its process.

Returns

The process of the currently running thread.

Definition at line 131 of file process.h.

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process_current_unsafe()

static process_t * process_current_unsafe ( void  )

inlinestatic

Retrieves the process of the currently running thread without disabling interrupts.

Note

Will not increment the reference count of the returned process, as we consider the currently running thread to always be referencing its process.

Returns

The process of the currently running thread.

Definition at line 145 of file process.h.

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process_get()

process_t * process_get

(

pid_t

id

)

Gets a process by its ID.

It is the responsibility of the caller to UNREF() the returned process.

Parameters

id	The ID of the process to get.

Returns

A reference to the process with the specified ID or NULL if no such process exists.

Definition at line 192 of file process.c.

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process_get_ns()

namespace_t * process_get_ns

(

process_t *

process

)

Gets the namespace of a process.

It is the responsibility of the caller to UNREF() the returned namespace.

Parameters

process

The process to get the namespace of.

Returns

On success, a reference to the namespace of the process. On failure, NULL and errno is set:

• EINVAL: Invalid parameters.

Definition at line 206 of file process.c.

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process_set_ns()

void process_set_ns	(	process_t *	process,
		namespace_t *	ns
	)

Sets the namespace of a process.

Parameters

process	The process to set the namespace of.
ns	The new namespace for the process.

Definition at line 227 of file process.c.

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process_kill()

void process_kill	(	process_t *	process,
		const char *	status
	)

Kills a process, pushing it to the reaper.

The process will still exist until the reaper removes it.

Parameters

process	The process to kill.
status	The exit status of the process.

Definition at line 240 of file process.c.

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process_remove()

void process_remove

(

process_t *

process

)

Removes a process from the system.

This should only be called by the reaper.

Parameters

process

The process to remove.

Definition at line 284 of file process.c.

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process_rcu_first_thread()

static thread_t * process_rcu_first_thread ( process_t *  process )

inlinestatic

Gets the first thread of a process.

Warning

Must be used within a RCU read-side critical section.

Parameters

process

The process to get the first thread of.

Returns

The first thread of the process, or NULL if the process has no threads.

Definition at line 206 of file process.h.

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process_rcu_thread_count()

static uint64_t process_rcu_thread_count ( process_t *  process )

inlinestatic

Gets the amount of threads in a process.

Warning

Must be used within a RCU read-side critical section.

Parameters

process

The process to get the thread amount of.

Returns

The amount of threads in the process.

Definition at line 219 of file process.h.

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process_set_cmdline()

uint64_t process_set_cmdline	(	process_t *	process,
		char **	argv,
		uint64_t	argc
	)

Sets the command line arguments for a process.

This value is only used for the /proc/[pid]/cmdline file.

Parameters

process	The process to set the cmdline for.
argv	The array of argument strings.
argc	The number of arguments.

Returns

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

• EINVAL: Invalid parameters.
• ENOMEM: Out of memory.

Definition at line 294 of file process.c.

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process_has_thread()

bool process_has_thread	(	process_t *	process,
		tid_t	tid
	)

Checks if a process has a thread with the specified thread ID.

Parameters

process	The process to check.
tid	The thread ID to look for.

Returns

true if the process has a thread with the specified ID, false otherwise.

Definition at line 358 of file process.c.

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process_get_kernel()

process_t * process_get_kernel

(

void

)

Gets the kernel process.

The kernel process will be initalized lazily on the first call to this function, which should happen during early boot.

Will never return NULL and will not increment the reference count of the returned process.

Returns

The kernel process.

Definition at line 374 of file process.c.

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Variable Documentation

_processes

list_t _processes

extern

Global list of all processes.

Warning

Should only be read while in a RCU read-side critical section.