proc.h File Reference

#include <core/system.h>
#include <mm/vm.h>
#include <fs/vfs.h>
#include <ds/queue.h>
#include <sys/waitq.h>
#include <sys/thread.h>
#include <sys/signal.h>
#include <dev/dev.h>

Go to the source code of this file.

Data Structures
struct	session
	A session: its process groups, and its controlling terminal. More...
struct	fd
	A file descriptor: the open file it refers to (fs/file.c, shared with the descriptors that dup() and fork() copied), and its own flags. More...
struct	pgroup
	A process group: the processes of a job. More...
struct	proc
	A process. More...

Macros
#define	FD_RESERVED   ((struct file *) -1)
#define	PROC_EXIT(info, code)
#define	PROC_UIO(proc)

Functions
int	proc_fork (struct thread *thread, struct proc **ref)
	Makes a child process, a copy of the process of thread.
int	proc_execve (struct thread *thread, const char *fn, char *const argv[], char *const env[])
	Runs another program in a thread's process, for execve().
void	init_execve (struct proc *proc, int argc, char *const argv[], int envc, char *const envp[])
	Sets up init, the first process, to start its program: its initial stack with its arguments and environment, before it first runs.
pid_t	proc_pid_alloc (void)
	Allocates a process ID, from 1 (init's) on.
void	proc_pid_free (int pid)
	Frees a process ID.
struct proc *	proc_pid_find (pid_t pid)
	Finds a process by its ID.
int	proc_new (struct proc **ref)
	Makes a new process structure, with one thread and an empty address space, on the list of every process.
int	session_new (struct proc *proc)
	Makes a new session, with a new process group, both led by a process and with its ID, and moves the process into it, as setsid() does.
int	proc_setpgid (struct proc *proc, pid_t pgid)
	Moves a process into a process group of its session, as setpgid() does.
void	pgrp_release (struct pgroup *pgrp)
	Frees a process group if no process is left in it, and its session if that was the session's last group.
int	pgrp_orphaned (struct pgroup *pgrp, struct proc *gone)
	Says whether a process group is orphaned (POSIX): none of its members has a parent in another group of the same session, so no one there would continue it once it stops.
void	proc_kill (struct proc *proc)
	Ends a process: its threads end, its descriptors are closed, its memory is freed, its children go to init, and it becomes a zombie that its parent may wait for.
int	proc_threads_end (struct proc *proc, struct thread *keep, int exiting)
	Ends the threads of a process, but one.
void	proc_threads_exec (struct proc *proc)
	Ends every thread of a process but the current one, for execve() (POSIX: they run in the program that is replaced).
int	proc_reap (struct proc *proc)
	Frees a zombie, once its parent waited for it (or doesn't wait for its children).
int	proc_fd_get (struct proc *proc)
	Reserves the lowest free descriptor of a process, while a system call sets it up: no other thread takes it, and it doesn't refer to a file yet.
void	proc_fd_release (struct proc *proc, int fd)
	Frees a reserved descriptor that wasn't set up after all.
void	proc_fd_install (struct proc *proc, int fd, struct file *file, int flags)
	Makes a reserved descriptor refer to an open file.
struct file *	proc_fd_file (struct proc *proc, int fd)
	Finds the open file a descriptor refers to.
int	proc_fd_close (struct proc *proc, int fd)
	Closes a descriptor: it is free again, and its reference to the open file is dropped.
void	proc_dump (struct proc *proc)
int	proc_init (struct proc *proc)
	Gives a new process (init) its ID and its descriptor table.

Variables
struct queue *	procs
struct proc *	initproc
struct queue *	sessions

Macro Definition Documentation

FD_RESERVED

#define FD_RESERVED   ((struct file *) -1)

Definition at line 53 of file proc.h.

Referenced by proc_fd_file(), and proc_fd_get().

PROC_EXIT

#define PROC_EXIT	(		info,
			code )

Value:

((((info) & 0xff) << 8) | ((code) & 0xff))

Definition at line 207 of file proc.h.

Referenced by proc_execve(), signal_exit(), and sys_exit().

PROC_UIO

#define PROC_UIO

(

proc

)

Value:

((struct uio){.cwd = (proc)->cwd, .uid = (proc)->uid, .gid = (proc)->gid, .mask = (proc)->mask})

Definition at line 210 of file proc.h.

Referenced by at_uio(), binfmt_load(), cwd_set(), exec_script(), socket_unix_bind(), socket_unix_connect(), sys_chdir(), sys_fchmod(), sys_fchown(), sys_mount(), and sys_utimensat().

Function Documentation

init_execve()

void init_execve	(	struct proc *	proc,
		int	argc,
		char *const	argv[],
		int	envc,
		char *const	envp[] )

Sets up init, the first process, to start its program: its initial stack with its arguments and environment, before it first runs.

The kernel calls it at boot, when no process runs yet.

Parameters

proc	init's process, with its program loaded
argc	how many arguments there are
argv	the arguments, in kernel memory
envc	how many environment strings there are
envp	the environment strings, in kernel memory

Definition at line 332 of file execve.c.

References curthread, exec_start(), queue::head, init_execve(), NULL, vm_space::pmap, pmap_switch(), proc::threads, qnode::value, and proc::vm_space.

Referenced by init_execve(), and kmain().

pgrp_orphaned()

int pgrp_orphaned	(	struct pgroup *	pgrp,
		struct proc *	gone )

Says whether a process group is orphaned (POSIX): none of its members has a parent in another group of the same session, so no one there would continue it once it stops.

Init doesn't count as such a parent, since it isn't a shell.

Parameters

pgrp	the process group
gone	a process on its way out, which doesn't count as a member or a parent; or NULL

Returns

1 if it is orphaned, 0 if not

Definition at line 227 of file proc.c.

References initproc, proc::parent, proc::pgrp, pgrp_orphaned(), pgroup::procs, queue_for, pgroup::session, and proc::zombie.

Referenced by pgrp_orphaned(), pgrp_orphaned_hangup(), signal_take(), and tty_background().

pgrp_release()

void pgrp_release

(

struct pgroup *

pgrp

)

Frees a process group if no process is left in it, and its session if that was the session's last group.

A terminal whose foreground group or session it was loses it.

Parameters

pgrp	the process group

Definition at line 742 of file proc.c.

References queue::count, session::ctty, tty::fg, kfree(), NULL, session::pgps, pgrp_release(), pgroup::procs, pgroup::session, tty::session, and pgroup::session_node.

Referenced by pgrp_release(), proc_reap(), proc_setpgid(), and sys_setsid().

proc_dump()

void proc_dump

(

struct proc *

proc

)

References proc_dump(), and proc_init().

Referenced by proc_dump().

proc_execve()

int proc_execve	(	struct thread *	thread,
		const char *	fn,
		char *const	_argp[],
		char *const	_envp[] )

Runs another program in a thread's process, for execve().

On success, the thread starts the new program when it returns to user mode.

Parameters

thread	the thread calling execve()
fn	the program's path
_argp	the arguments, in user memory
_envp	the environment, in user memory

Returns

0, or a negative errno: -EFAULT, -E2BIG, -ENOMEM, -ELOOP (too many nested scripts), or the loader's. If loading fails after the old program is gone, the process is killed (SIGSEGV) instead.

Definition at line 358 of file execve.c.

References arch_sleep(), binfmt_load(), queue::count, EXEC_ARG_MAX, exec_script(), exec_script_args(), EXEC_SCRIPT_DEPTH, exec_start(), exec_strings_free(), exec_strings_get(), proc::exit, proc::fds, FDS_COUNT, fd::flags, kfree(), kmalloc(), NULL, thread::owner, proc_execve(), PROC_EXIT, proc_fd_close(), proc_fd_file(), proc_kill(), SIG_DFL, SIG_IGN, SIG_MAX, proc::sigaction, thread::spawned, vm_space::vm_entries, and proc::vm_space.

Referenced by proc_execve(), and sys_execve().

proc_fd_close()

int proc_fd_close	(	struct proc *	proc,
		int	fd )

Closes a descriptor: it is free again, and its reference to the open file is dropped.

Dropping the last reference closes the file.

Parameters

proc	the process
fd	the descriptor

Returns

what closing the file returned (0 or a negative errno), or -EBADF if the descriptor isn't open

Definition at line 578 of file proc.c.

References proc::fds, file_put(), proc_fd_close(), and proc_fd_file().

Referenced by proc_execve(), proc_fd_close(), proc_fork(), proc_kill(), sys_accept(), sys_close(), and sys_pipe().

proc_fd_file()

struct file * proc_fd_file	(	struct proc *	proc,
		int	fd )

Finds the open file a descriptor refers to.

Parameters

proc	the process
fd	the descriptor

Returns

the open file, or NULL if the descriptor is free, being set up, or out of range

Definition at line 560 of file proc.c.

References FD_RESERVED, proc::fds, FDS_COUNT, fd::file, NULL, and proc_fd_file().

Referenced by copy_fds(), fd_file(), fd_peek(), proc_execve(), proc_fd_close(), and proc_fd_file().

proc_fd_get()

int proc_fd_get

(

struct proc *

proc

)

Reserves the lowest free descriptor of a process, while a system call sets it up: no other thread takes it, and it doesn't refer to a file yet.

proc_fd_install() or proc_fd_release() ends the reservation.

Parameters

proc	the process

Returns

the descriptor, or -1 if there is no free one

Definition at line 514 of file proc.c.

References FD_RESERVED, proc::fds, FDS_COUNT, fd::file, and proc_fd_get().

Referenced by do_openat(), proc_fd_get(), sys_accept(), sys_pipe(), and sys_socket().

proc_fd_install()

void proc_fd_install	(	struct proc *	proc,
		int	fd,
		struct file *	file,
		int	flags )

Makes a reserved descriptor refer to an open file.

The caller's reference to the file becomes the descriptor's.

Parameters

proc	the process
fd	the descriptor, reserved by proc_fd_get()
file	the open file
flags	the descriptor's flags (FD_CLOEXEC)

Definition at line 547 of file proc.c.

References proc::fds, fd::file, fd::flags, file::flags, and proc_fd_install().

Referenced by do_openat(), proc_fd_install(), sys_accept(), sys_fcntl(), sys_pipe(), and sys_socket().

proc_fd_release()

void proc_fd_release	(	struct proc *	proc,
		int	fd )

Frees a reserved descriptor that wasn't set up after all.

Parameters

proc	the process
fd	the descriptor

Definition at line 532 of file proc.c.

References proc::fds, FDS_COUNT, and proc_fd_release().

Referenced by do_openat(), proc_fd_release(), sys_accept(), sys_pipe(), and sys_socket().

proc_fork()

int proc_fork	(	struct thread *	thread,
		struct proc **	ref )

Makes a child process, a copy of the process of thread.

The child's one thread is a copy of thread, which will return 0 from fork(); it isn't made ready to run, the caller does that.

Parameters

thread	the thread calling fork()
ref	if not NULL, set to the child

Returns

0, or a negative errno: -ENOMEM, or -EAGAIN if there is no free process ID

Definition at line 81 of file fork.c.

References arch_proc_fork(), arch_syscall_return(), copy_fds(), proc::cwd, proc::fds, FDS_COUNT, fork_proc_copy(), queue::head, proc::heap_vm, kfree(), proc::name, qnode::next, NULL, thread::owner, proc::parent, proc::pgrp, proc::pgrp_node, proc::pid, vm_space::pmap, pmap_decref(), proc_fd_close(), proc_fork(), proc_new(), proc_pid_alloc(), proc_pid_free(), pgroup::procs, procs, vnode::ref, thread::spawned, proc::stack_vm, proc::threads, qnode::value, vfs_close(), vm_space::vm_entries, proc::vm_space, vm_space_destroy(), and vm_space_fork().

Referenced by proc_fork(), and sys_fork().

proc_init()

int proc_init

(

struct proc *

proc

)

Gives a new process (init) its ID and its descriptor table.

Parameters

proc	the process

Returns

0, -EINVAL if proc is NULL, -EAGAIN if no ID is free, or -ENOMEM

Definition at line 197 of file proc.c.

References proc::fds, FDS_COUNT, kmalloc(), M_ZERO, proc::pid, proc_init(), proc_pid_alloc(), and proc_pid_free().

Referenced by proc_dump(), proc_init(), and sched_init_spawn().

proc_kill()

void proc_kill

(

struct proc *

proc

)

Ends a process: its threads end, its descriptors are closed, its memory is freed, its children go to init, and it becomes a zombie that its parent may wait for.

If the current thread is the process's, it doesn't return. Ending init restarts the machine.

Parameters

proc	the process; its exit status is set already

Definition at line 375 of file proc.c.

References arch_cur_thread_kill(), arch_interrupts_disable(), arch_reboot(), session::ctty, curthread, proc::cwd, proc::exit, proc::fds, FDS_COUNT, queue::head, initproc, kfree(), kvm_space, session::leader, qnode::next, NULL, panic, proc::parent, proc::pgrp, pgrp_orphaned_hangup(), pgrp_other_same_session(), proc::pid, vm_space::pmap, pmap_decref(), printk(), proc_fd_close(), proc_kill(), proc_threads_end(), proc_zombie_notify(), procs, proc::running, sched_alarm(), pgroup::session, proc::sig_pending, thread_files_release(), proc::threads, tty_hangup(), qnode::value, vfs_close(), proc::vm_space, vm_space_destroy(), and proc::zombie.

Referenced by proc_execve(), proc_kill(), signal_exit(), and sys_exit().

proc_new()

int proc_new

(

struct proc **

ref

)

Makes a new process structure, with one thread and an empty address space, on the list of every process.

It has no ID yet.

Parameters

ref	if not NULL, set to the new process

Returns

0, or -ENOMEM

Definition at line 114 of file proc.c.

References kfree(), kmalloc(), M_ZERO, NULL, vm_space::pmap, pmap_create(), pmap_decref(), proc_new(), procs, pmap::ref, proc::running, SIG_DFL, SIG_MAX, proc::sigaction, thread_new(), proc::threads, and proc::vm_space.

Referenced by kmain(), proc_fork(), and proc_new().

proc_pid_alloc()

pid_t proc_pid_alloc

(

void

)

Allocates a process ID, from 1 (init's) on.

Returns

the ID, or -1 if none is free

Definition at line 80 of file proc.c.

References last_pid, bitmap::max_idx, pid_bitmap, pid_is_group(), and proc_pid_alloc().

Referenced by proc_fork(), proc_init(), and proc_pid_alloc().

proc_pid_find()

struct proc * proc_pid_find

(

pid_t

pid

)

Finds a process by its ID.

Parameters

pid

the ID

Returns

the process (it may be a zombie), or NULL

Definition at line 179 of file proc.c.

References NULL, proc::pid, proc_pid_find(), procs, and queue_for.

Referenced by kernel_ctrlaltdel(), proc_alive(), proc_pid_find(), procfs_proc_maps(), procfs_proc_status(), procfs_proc_vmstats(), signal_send(), sys_setpgid(), and vt_signal().

proc_pid_free()

void proc_pid_free

(

int

pid

)

Frees a process ID.

Parameters

pid

the ID

Definition at line 102 of file proc.c.

References pid_bitmap, and proc_pid_free().

Referenced by proc_fork(), proc_init(), proc_pid_free(), and proc_reap().

proc_reap()

int proc_reap

(

struct proc *

proc

)

Frees a zombie, once its parent waited for it (or doesn't wait for its children).

Its CPU times are added to its parent's children's times.

Parameters

proc	the zombie

Returns

0

Definition at line 484 of file proc.c.

References proc::cstime, proc::cutime, kfree(), proc::name, proc::parent, proc::pgrp, proc::pgrp_node, pgrp_release(), proc::pid, proc_pid_free(), proc_reap(), pgroup::procs, procs, proc::stime, and proc::utime.

Referenced by proc_reap(), proc_zombie_notify(), and sys_waitpid().

proc_setpgid()

int proc_setpgid	(	struct proc *	proc,
		pid_t	pgid )

Moves a process into a process group of its session, as setpgid() does.

A group can only be joined if it exists and has members; a process can only start a new group with its own ID as the group's ID.

Parameters

proc	the process
pgid	the group's ID

Returns

0, -EPERM if there is no such group and pgid isn't the process's ID, or -ENOMEM

Definition at line 667 of file proc.c.

References queue::count, kfree(), kmalloc(), pgroup::leader, M_ZERO, NULL, pgroup::pgid, session::pgps, proc::pgrp, proc::pgrp_node, pgrp_release(), proc::pid, proc_setpgid(), pgroup::procs, queue_for, pgroup::session, and pgroup::session_node.

Referenced by proc_setpgid(), and sys_setpgid().

proc_threads_end()

int proc_threads_end	(	struct proc *	proc,
		struct thread *	keep,
		int	exiting )

Ends the threads of a process, but one.

A thread that isn't running is freed. One running on another CPU (in user mode, since this CPU has the kernel lock) is marked killed and made to enter the kernel now, where it frees itself.

Parameters

proc	the process
keep	the thread to keep, or NULL
exiting	whether the process is ending: then the threads running elsewhere are detached from it at once; otherwise they leave its list when they go, and wake up proc->thread_join

Returns

how many threads were running on other CPUs

Definition at line 305 of file proc.c.

References queue::head, kfree(), thread::killed, NULL, thread::owner, proc_threads_end(), thread::run_link, sched_thread_cpu(), sched_thread_kick(), sched_timer_cancel(), thread::state, thread_files_release(), thread_kill(), proc::threads, thread::waitq, and ZOMBIE.

Referenced by proc_kill(), proc_threads_end(), and proc_threads_exec().

proc_threads_exec()

void proc_threads_exec

(

struct proc *

proc

)

Ends every thread of a process but the current one, for execve() (POSIX: they run in the program that is replaced).

It waits for the threads running on other CPUs to be gone.

Parameters

proc	the process, which must be the current thread's

Definition at line 358 of file proc.c.

References curthread, proc_threads_end(), proc_threads_exec(), proc::thread_join, and waitq_sleep_unint().

Referenced by binfmt_fmt_load(), and proc_threads_exec().

session_new()

int session_new

(

struct proc *

proc

)

Makes a new session, with a new process group, both led by a process and with its ID, and moves the process into it, as setsid() does.

Parameters

proc	the process

Returns

0, or -ENOMEM

Definition at line 596 of file proc.c.

References kfree(), kmalloc(), pgroup::leader, session::leader, M_ZERO, NULL, pgroup::pgid, session::pgps, proc::pgrp, proc::pgrp_node, proc::pid, pgroup::procs, pgroup::session, session_new(), pgroup::session_node, and session::sid.

Referenced by kproc_init(), sched_init_spawn(), session_new(), and sys_setsid().

Variable Documentation

initproc

struct proc* initproc

extern

Definition at line 39 of file proc.c.

Referenced by kmain(), pgrp_orphaned(), and proc_kill().

procs

struct queue* procs

extern

Definition at line 37 of file proc.c.

Referenced by kproc_init(), proc_fork(), proc_kill(), proc_new(), proc_pid_find(), proc_reap(), procfs_finddir(), procfs_readdir(), signal_send(), and sys_waitpid().

sessions

struct queue* sessions

extern

Definition at line 42 of file proc.c.

Referenced by pid_is_group().