1/*-
2 * Copyright (c) 2009 Robert N. M. Watson
3 * All rights reserved.
4 *
5 * This software was developed at the University of Cambridge Computer
6 * Laboratory with support from a grant from Google, Inc.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32#ifndef _SYS_PROCDESC_H_
33#define	_SYS_PROCDESC_H_
34
35#ifdef _KERNEL
36#include <sys/selinfo.h>	/* struct selinfo */
37#include <sys/_lock.h>
38#include <sys/_mutex.h>
39
40/*-
41 * struct procdesc describes a process descriptor, and essentially consists
42 * of two pointers -- one to the file descriptor, and one to the process.
43 * When both become NULL, the process descriptor will be freed.  An important
44 * invariant is that there is only ever one process descriptor for a process,
45 * so a single file pointer will suffice.
46 *
47 * Locking key:
48 * (c) - Constant after initial setup.
49 * (p) - Protected by the process descriptor mutex.
50 * (r) - Atomic reference count.
51 * (s) - Protected by selinfo.
52 * (t) - Protected by the proctree_lock
53 */
54struct proc;
55struct sigio;
56struct procdesc {
57	/*
58	 * Basic process descriptor state: the process, a cache of its pid to
59	 * satisfy queries after the process exits, and process descriptor
60	 * refcount.
61	 */
62	struct proc	*pd_proc;		/* (t) Process. */
63	pid_t		 pd_pid;		/* (c) Cached pid. */
64	u_int		 pd_refcount;		/* (r) Reference count. */
65
66	/*
67	 * In-flight data and notification of events.
68	 */
69	int		 pd_flags;		/* (p) PD_ flags. */
70	struct selinfo	 pd_selinfo;		/* (p) Event notification. */
71	struct mtx	 pd_lock;		/* Protect data + events. */
72};
73
74/*
75 * Locking macros for the procdesc itself.
76 */
77#define	PROCDESC_LOCK_DESTROY(pd)	mtx_destroy(&(pd)->pd_lock)
78#define	PROCDESC_LOCK_INIT(pd)	mtx_init(&(pd)->pd_lock, "procdesc", NULL, \
79				    MTX_DEF)
80#define	PROCDESC_LOCK(pd)	mtx_lock(&(pd)->pd_lock)
81#define	PROCDESC_UNLOCK(pd)	mtx_unlock(&(pd)->pd_lock)
82
83/*
84 * Flags for the pd_flags field.
85 */
86#define	PDF_CLOSED	0x00000001	/* Descriptor has closed. */
87#define	PDF_SELECTED	0x00000002	/* Issue selwakeup(). */
88#define	PDF_EXITED	0x00000004	/* Process exited. */
89#define	PDF_DAEMON	0x00000008	/* Don't exit when procdesc closes. */
90
91/*
92 * In-kernel interfaces to process descriptors.
93 */
94int	 procdesc_exit(struct proc *);
95int	 procdesc_find(struct thread *, int fd, cap_rights_t *, struct proc **);
96int	 kern_pdgetpid(struct thread *, int fd, cap_rights_t *, pid_t *pidp);
97void	 procdesc_new(struct proc *, int);
98void	 procdesc_finit(struct procdesc *, struct file *);
99pid_t	 procdesc_pid(struct file *);
100void	 procdesc_reap(struct proc *);
101
102#else /* !_KERNEL */
103
104/*
105 * Process descriptor system calls.
106 */
107struct rusage;
108int	 pdfork(int *, int);
109int	 pdkill(int, int);
110int	 pdgetpid(int, pid_t *);
111
112#endif /* _KERNEL */
113
114/*
115 * Flags which can be passed to pdfork(2).
116 */
117#define	PD_DAEMON	0x00000001	/* Don't exit when procdesc closes. */
118
119#endif /* !_SYS_PROCDESC_H_ */
120