sys/sys/procdesc.h

root/sys/sys/procdesc.h
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009 Robert N. M. Watson
 * All rights reserved.
 *
 * This software was developed at the University of Cambridge Computer
 * Laboratory with support from a grant from Google, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _SYS_PROCDESC_H_
#define _SYS_PROCDESC_H_

#ifdef _KERNEL

#include <sys/selinfo.h>        /* struct selinfo */
#include <sys/_lock.h>
#include <sys/_mutex.h>

/*-
 * struct procdesc describes a process descriptor, and essentially consists
 * of two pointers -- one to the file descriptor, and one to the process.
 * When both become NULL, the process descriptor will be freed.  An important
 * invariant is that there is only ever one process descriptor for a process,
 * so a single file pointer will suffice.
 *
 * Locking key:
 * (c) - Constant after initial setup.
 * (p) - Protected by the process descriptor mutex.
 * (r) - Atomic reference count.
 * (s) - Protected by selinfo.
 * (t) - Protected by the proctree_lock
 */
struct proc;
struct sigio;
struct procdesc {
        /*
         * Basic process descriptor state: the process, a cache of its pid to
         * satisfy queries after the process exits, and process descriptor
         * refcount.
         */
        struct proc     *pd_proc;               /* (t) Process. */
        pid_t            pd_pid;                /* (c) Cached pid. */
        u_int            pd_refcount;           /* (r) Reference count. */

        /*
         * In-flight data and notification of events.
         */
        int              pd_flags;              /* (p) PD_ flags. */
        u_short          pd_xstat;              /* (p) Exit status. */
        struct selinfo   pd_selinfo;            /* (p) Event notification. */
        struct mtx       pd_lock;               /* Protect data + events. */
};

/*
 * Locking macros for the procdesc itself.
 */
#define PROCDESC_LOCK_DESTROY(pd)       mtx_destroy(&(pd)->pd_lock)
#define PROCDESC_LOCK_INIT(pd)  mtx_init(&(pd)->pd_lock, "procdesc", NULL, \
                                    MTX_DEF)
#define PROCDESC_LOCK(pd)       mtx_lock(&(pd)->pd_lock)
#define PROCDESC_UNLOCK(pd)     mtx_unlock(&(pd)->pd_lock)

/*
 * Flags for the pd_flags field.
 */
#define PDF_CLOSED      0x00000001      /* Descriptor has closed. */
#define PDF_SELECTED    0x00000002      /* Issue selwakeup(). */
#define PDF_EXITED      0x00000004      /* Process exited. */
#define PDF_DAEMON      0x00000008      /* Don't exit when procdesc closes. */

/*
 * In-kernel interfaces to process descriptors.
 */
int      procdesc_exit(struct proc *);
int      procdesc_find(struct thread *, int fd, const cap_rights_t *,
            struct proc **);
int      kern_pdgetpid(struct thread *, int fd, const cap_rights_t *,
            pid_t *pidp);
void     procdesc_new(struct proc *, int);
void     procdesc_finit(struct procdesc *, struct file *);
pid_t    procdesc_pid(struct file *);
void     procdesc_reap(struct proc *);

int      procdesc_falloc(struct thread *, struct file **, int *, int,
            struct filecaps *);

#else /* !_KERNEL */

#include <sys/cdefs.h>
#include <sys/_types.h>

#ifndef _PID_T_DECLARED
typedef __pid_t         pid_t;
#define _PID_T_DECLARED
#endif

struct rusage;

/*
 * Process descriptor system calls.
 */
__BEGIN_DECLS
struct __wrusage;
struct __siginfo;

pid_t    pdfork(int *, int);
pid_t    pdrfork(int *, int, int);
int      pdkill(int, int);
int      pdgetpid(int, pid_t *);
int      pdwait(int, int *, int, struct __wrusage *, struct __siginfo *);
pid_t    pdrfork_thread(int *, int, int, void *, int (*)(void *), void *);
__END_DECLS

#endif /* _KERNEL */

/*
 * Flags which can be passed to pdfork(2).
 */
#define PD_DAEMON       0x00000001      /* Don't exit when procdesc closes. */
#define PD_CLOEXEC      0x00000002      /* Close file descriptor on exec. */

#define PD_ALLOWED_AT_FORK      (PD_DAEMON | PD_CLOEXEC)

#endif /* !_SYS_PROCDESC_H_ */
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