Category : Files from Magazines
Archive   : DDJ8_91.ZIP
Filename : 386BSD.ASC

_PORTING UNIX TO THE 386: THE BASIC KERNEL_
by William Frederick Jolitz and Lynne Greer Jolitz

[LISTING ONE]

/* Copyright (c) 1986, 1989, 1991 The Regents of the University of California.
* All rights reserved.
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
* @(#)proc.h 7.28 (Berkeley) 5/30/91
*/

#ifndef _PROC_H_
#define _PROC_H_

#include /* machine-dependent proc substruct */

/* One structure allocated per session. */
struct session {
int s_count; /* ref cnt; pgrps in session */
struct proc *s_leader; /* session leader */
struct vnode *s_ttyvp; /* vnode of controlling terminal */
struct tty *s_ttyp; /* controlling terminal */
char s_login[MAXLOGNAME]; /* setlogin() name */
};
/* One structure allocated per process group. */
struct pgrp {
struct pgrp *pg_hforw; /* forward link in hash bucket */
struct proc *pg_mem; /* pointer to pgrp members */
struct session *pg_session; /* pointer to session */
pid_t pg_id; /* pgrp id */
int pg_jobc; /* # procs qualifying pgrp for job control */
};
/* Description of a process. This structure contains information needed to
* manage a thread of control, known in UNIX as a process; it has references
* to substructures containing descriptions of things that process uses, but
* may share with related processes. Process structure and substructures are
* always addressible except for those marked "(PROC ONLY)" below, which might
* be addressible only on a processor on which the process is running. */
struct proc {
struct proc *p_link; /* doubly-linked run/sleep queue */
struct proc *p_rlink;
struct proc *p_nxt; /* linked list of active procs */
struct proc **p_prev; /* and zombies */
/* substructures: */
struct pcred *p_cred; /* process owner's identity */
struct filedesc *p_fd; /* ptr to open files structure */
struct pstats *p_stats; /* accounting/statistics (PROC ONLY) */
struct plimit *p_limit; /* process limits */
struct vmspace *p_vmspace; /* address space */
struct sigacts *p_sigacts; /* signal actions, state (PROC ONLY) */
#define p_ucred p_cred->pc_ucred
#define p_rlimit p_limit->pl_rlimit
int p_flag;
char p_stat;

pid_t p_pid; /* unique process id */
struct proc *p_hash; /* hashed based on p_pid for kill+exit+... */
struct proc *p_pgrpnxt; /* pointer to next process in process group */
struct proc *p_pptr; /* pointer to process structure of parent */
struct proc *p_osptr; /* pointer to older sibling processes */
/* The following fields are all zeroed upon creation in fork */
#define p_startzero p_ysptr
struct proc *p_ysptr; /* pointer to younger siblings */
struct proc *p_cptr; /* pointer to youngest living child */
/* scheduling */
u_int p_cpu; /* cpu usage for scheduling */
int p_cpticks; /* ticks of cpu time */
fixpt_t p_pctcpu; /* %cpu for this process during p_time */
caddr_t p_wchan; /* event process is awaiting */
u_int p_time; /* resident/nonresident time for swapping */
u_int p_slptime; /* time since last block */
struct itimerval p_realtimer; /* alarm timer */
struct timeval p_utime; /* user time */
struct timeval p_stime; /* system time */
int p_traceflag; /* kernel trace points */
struct vnode *p_tracep;/* trace to vnode */
int p_sig; /* signals pending to this process */
/* end area that is zeroed on creation */
#define p_endzero p_startcopy
/* The following fields are all copied upon creation in fork */
sigset_t p_sigmask; /* current signal mask */
#define p_startcopy p_sigmask
sigset_t p_sigignore; /* signals being ignored */
sigset_t p_sigcatch; /* signals being caught by user */
u_char p_pri; /* priority, negative is high */
u_char p_usrpri; /* user-priority based on p_cpu and p_nice */
char p_nice; /* nice for cpu usage */
struct pgrp *p_pgrp; /* pointer to process group */
char p_comm[MAXCOMLEN+1];
/* end area that is copied on creation */
#define p_endcopy p_wmesg
char *p_wmesg; /* reason for sleep */
struct user *p_addr; /* kernel virtual addr of u-area (PROC ONLY) */
swblk_t p_swaddr; /* disk address of u area when swapped */
int *p_regs; /* saved registers during syscall/trap */
struct mdproc p_md; /* any machine-dependent fields */
u_short p_xstat; /* Exit status for wait; also stop signal */
u_short p_acflag; /* accounting flags */
};
#define p_session p_pgrp->pg_session
#define p_pgid p_pgrp->pg_id
/* Shareable process credentials (always resident). Includes a reference to
* current user credentials as well as real and saved ids that may be used to
* change ids. */
struct pcred {
struct ucred *pc_ucred; /* current credentials */
uid_t p_ruid; /* real user id */
uid_t p_svuid; /* saved effective user id */
gid_t p_rgid; /* real group id */
gid_t p_svgid; /* saved effective group id */
int p_refcnt; /* number of references */
};
/* stat codes */
#define SSLEEP 1 /* awaiting an event */
#define SWAIT 2 /* (abandoned state) */
#define SRUN 3 /* running */
#define SIDL 4 /* intermediate state in process creation */
#define SZOMB 5 /* intermediate state in process termination */
#define SSTOP 6 /* process being traced */
/* flag codes */
#define SLOAD 0x0000001 /* in core */
#define SSYS 0x0000002 /* swapper or pager process */
#define SSINTR 0x0000004 /* sleep is interruptible */
#define SCTTY 0x0000008 /* has a controlling terminal */
#define SPPWAIT 0x0000010 /* parent is waiting for child to exec/exit */
#define SEXEC 0x0000020 /* process called exec */
#define STIMO 0x0000040 /* timing out during sleep */
#define SSEL 0x0000080 /* selecting; wakeup/waiting danger */
#define SWEXIT 0x0000100 /* working on exiting */
#define SNOCLDSTOP 0x0000200 /* no SIGCHLD when children stop */
#define STRC 0x0004000 /* process is being traced */
#define SWTED 0x0008000 /* another tracing flag */
#define SADVLCK 0x0040000 /* process may hold a POSIX advisory lock */

#ifdef KERNEL
/* We use process IDs <= PID_MAX; PID_MAX + 1 must also fit in a pid_t
* (used to represent "no process group"). */
#define PID_MAX 30000
#define NO_PID 30001
#define PIDHASH(pid) ((pid) & pidhashmask)
#define SESS_LEADER(p) ((p)->p_session->s_leader == (p))
#define SESSHOLD(s) ((s)->s_count++)
#define SESSRELE(s) { \
if (--(s)->s_count == 0) \
FREE(s, M_SESSION); \
}
extern int pidhashmask; /* in param.c */
extern struct proc *pidhash[]; /* in param.c */
struct proc *pfind(); /* find process by id */
extern struct pgrp *pgrphash[]; /* in param.c */
struct pgrp *pgfind(); /* find process group by id */
struct proc *zombproc, *allproc; /* lists of procs in various states */
extern struct proc proc0; /* process slot for swapper */
struct proc *initproc, *pageproc; /* process slots for init, pager */
extern struct proc *curproc; /* current running proc */
extern int nprocs, maxproc; /* current and max number of procs */

#define NQS 32 /* 32 run queues */
struct prochd {
struct proc *ph_link; /* linked list of running processes */
struct proc *ph_rlink;
} qs[NQS];
int whichqs; /* bit mask summarizing non-empty qs's */
#endif /* KERNEL */
#endif /* !_PROC_H_ */