1/*-
  2 * SPDX-License-Identifier: BSD-2-Clause
  3 *
  4 * Copyright (c) 2009 Robert N. M. Watson
  5 * All rights reserved.
  6 *
  7 * This software was developed at the University of Cambridge Computer
  8 * Laboratory with support from a grant from Google, Inc.
  9 *
 10 * Redistribution and use in source and binary forms, with or without
 11 * modification, are permitted provided that the following conditions
 12 * are met:
 13 * 1. Redistributions of source code must retain the above copyright
 14 *    notice, this list of conditions and the following disclaimer.
 15 * 2. Redistributions in binary form must reproduce the above copyright
 16 *    notice, this list of conditions and the following disclaimer in the
 17 *    documentation and/or other materials provided with the distribution.
 18 *
 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 29 * SUCH DAMAGE.
 30 */
 31
 32#ifndef _SYS_PROCDESC_H_
 33#define	_SYS_PROCDESC_H_
 34
 35#ifdef _KERNEL
 36
 37#include <sys/selinfo.h>	/* struct selinfo */
 38#include <sys/_lock.h>
 39#include <sys/_mutex.h>
 40
 41/*-
 42 * struct procdesc describes a process descriptor, and essentially consists
 43 * of two pointers -- one to the file descriptor, and one to the process.
 44 * When both become NULL, the process descriptor will be freed.  An important
 45 * invariant is that there is only ever one process descriptor for a process,
 46 * so a single file pointer will suffice.
 47 *
 48 * Locking key:
 49 * (c) - Constant after initial setup.
 50 * (p) - Protected by the process descriptor mutex.
 51 * (r) - Atomic reference count.
 52 * (s) - Protected by selinfo.
 53 * (t) - Protected by the proctree_lock
 54 */
 55struct proc;
 56struct sigio;
 57struct procdesc {
 58	/*
 59	 * Basic process descriptor state: the process, a cache of its pid to
 60	 * satisfy queries after the process exits, and process descriptor
 61	 * refcount.
 62	 */
 63	struct proc	*pd_proc;		/* (t) Process. */
 64	pid_t		 pd_pid;		/* (c) Cached pid. */
 65	u_int		 pd_refcount;		/* (r) Reference count. */
 66
 67	/*
 68	 * In-flight data and notification of events.
 69	 */
 70	int		 pd_flags;		/* (p) PD_ flags. */
 71	u_short		 pd_xstat;		/* (p) Exit status. */
 72	struct selinfo	 pd_selinfo;		/* (p) Event notification. */
 73	struct mtx	 pd_lock;		/* Protect data + events. */
 74};
 75
 76/*
 77 * Locking macros for the procdesc itself.
 78 */
 79#define	PROCDESC_LOCK_DESTROY(pd)	mtx_destroy(&(pd)->pd_lock)
 80#define	PROCDESC_LOCK_INIT(pd)	mtx_init(&(pd)->pd_lock, "procdesc", NULL, \
 81				    MTX_DEF)
 82#define	PROCDESC_LOCK(pd)	mtx_lock(&(pd)->pd_lock)
 83#define	PROCDESC_UNLOCK(pd)	mtx_unlock(&(pd)->pd_lock)
 84
 85/*
 86 * Flags for the pd_flags field.
 87 */
 88#define	PDF_CLOSED	0x00000001	/* Descriptor has closed. */
 89#define	PDF_SELECTED	0x00000002	/* Issue selwakeup(). */
 90#define	PDF_EXITED	0x00000004	/* Process exited. */
 91#define	PDF_DAEMON	0x00000008	/* Don't exit when procdesc closes. */
 92
 93/*
 94 * In-kernel interfaces to process descriptors.
 95 */
 96int	 procdesc_exit(struct proc *);
 97int	 procdesc_find(struct thread *, int fd, cap_rights_t *, struct proc **);
 98int	 kern_pdgetpid(struct thread *, int fd, cap_rights_t *, pid_t *pidp);
 99void	 procdesc_new(struct proc *, int);
100void	 procdesc_finit(struct procdesc *, struct file *);
101pid_t	 procdesc_pid(struct file *);
102void	 procdesc_reap(struct proc *);
103
104int	 procdesc_falloc(struct thread *, struct file **, int *, int,
105	    struct filecaps *);
106
107#else /* !_KERNEL */
108
109#include <sys/_types.h>
110
111#ifndef _PID_T_DECLARED
112typedef	__pid_t		pid_t;
113#define	_PID_T_DECLARED
114#endif
115
116struct rusage;
117
118/*
119 * Process descriptor system calls.
120 */
121__BEGIN_DECLS
122pid_t	 pdfork(int *, int);
123int	 pdkill(int, int);
124int	 pdgetpid(int, pid_t *);
125__END_DECLS
126
127#endif /* _KERNEL */
128
129/*
130 * Flags which can be passed to pdfork(2).
131 */
132#define	PD_DAEMON	0x00000001	/* Don't exit when procdesc closes. */
133#define	PD_CLOEXEC	0x00000002	/* Close file descriptor on exec. */
134
135#define	PD_ALLOWED_AT_FORK	(PD_DAEMON | PD_CLOEXEC)
136
137#endif /* !_SYS_PROCDESC_H_ */