#/* *//* * Everything in this file is a routine implementing a system call. */#include "../param.h"#include "../user.h"#include "../reg.h"#include "../inode.h"#include "../systm.h"#include "../proc.h"getswit(){	u.u_ar0[R0] = SW->integ;}gtime(){	u.u_ar0[R0] = time[0];	u.u_ar0[R1] = time[1];}stime(){	if(suser()) {		time[0] = u.u_ar0[R0];		time[1] = u.u_ar0[R1];		wakeup(tout);	}}setuid(){	register uid;	uid = u.u_ar0[R0].lobyte;	if(u.u_ruid == uid.lobyte || suser()) {		u.u_uid = uid;		u.u_procp->p_uid = uid;		u.u_ruid = uid;	}}getuid(){	u.u_ar0[R0].lobyte = u.u_ruid;	u.u_ar0[R0].hibyte = u.u_uid;}setgid(){	register gid;	gid = u.u_ar0[R0].lobyte;	if(u.u_rgid == gid.lobyte || suser()) {		u.u_gid = gid;		u.u_rgid = gid;	}}getgid(){	u.u_ar0[R0].lobyte = u.u_rgid;	u.u_ar0[R0].hibyte = u.u_gid;}getpid(){	u.u_ar0[R0] = u.u_procp->p_pid;}sync(){	update();}nice(){	register n;	n = u.u_ar0[R0];	if(n > 20)		n = 20;	if(n < 0 && !suser())		n = 0;	u.u_procp->p_nice = n;}/* * Unlink system call. * panic: unlink -- "cannot happen" */unlink(){	register *ip, *pp;	extern uchar;	pp = namei(&uchar, 2);	if(pp == NULL)		return;	prele(pp);	ip = iget(pp->i_dev, u.u_dent.u_ino);	if(ip == NULL)		panic("unlink -- iget");	if((ip->i_mode&IFMT)==IFDIR && !suser())		goto out;	u.u_offset[1] =- DIRSIZ+2;	u.u_base = &u.u_dent;	u.u_count = DIRSIZ+2;	u.u_dent.u_ino = 0;	writei(pp);	ip->i_nlink--;	ip->i_flag =| IUPD;out:	iput(pp);	iput(ip);}chdir(){	register *ip;	extern uchar;	ip = namei(&uchar, 0);	if(ip == NULL)		return;	if((ip->i_mode&IFMT) != IFDIR) {		u.u_error = ENOTDIR;	bad:		iput(ip);		return;	}	if(access(ip, IEXEC))		goto bad;	iput(u.u_cdir);	u.u_cdir = ip;	prele(ip);}chmod(){	register *ip;	if ((ip = owner()) == NULL)		return;	ip->i_mode =& ~07777;	if (u.u_uid)		u.u_arg[1] =& ~ISVTX;	ip->i_mode =| u.u_arg[1]&07777;	ip->i_flag =| IUPD;	iput(ip);}chown(){	register *ip;	if (!suser() || (ip = owner()) == NULL)		return;	ip->i_uid = u.u_arg[1].lobyte;	ip->i_gid = u.u_arg[1].hibyte;	ip->i_flag =| IUPD;	iput(ip);}/* * Change modified date of file: * time to r0-r1; sys smdate; file * This call has been withdrawn because it messes up * incremental dumps (pseudo-old files aren't dumped). * It works though and you can uncomment it if you like.smdate(){	register struct inode *ip;	register int *tp;	int tbuf[2];	if ((ip = owner()) == NULL)		return;	ip->i_flag =| IUPD;	tp = &tbuf[2];	*--tp = u.u_ar0[R1];	*--tp = u.u_ar0[R0];	iupdat(ip, tp);	ip->i_flag =& ~IUPD;	iput(ip);}*/ssig(){	register a;	a = u.u_arg[0];	if(a<=0 || a>=NSIG || a ==SIGKIL) {		u.u_error = EINVAL;		return;	}	u.u_ar0[R0] = u.u_signal[a];	u.u_signal[a] = u.u_arg[1];	if(u.u_procp->p_sig == a)		u.u_procp->p_sig = 0;}kill(){	register struct proc *p, *q;	register a;	int f;	f = 0;	a = u.u_ar0[R0];	q = u.u_procp;	for(p = &proc[0]; p < &proc[NPROC]; p++) {		if(p == q)			continue;		if(a != 0 && p->p_pid != a)			continue;		if(a == 0 && (p->p_ttyp != q->p_ttyp || p <= &proc[1]))			continue;		if(u.u_uid != 0 && u.u_uid != p->p_uid)			continue;		f++;		psignal(p, u.u_arg[0]);	}	if(f == 0)		u.u_error = ESRCH;}times(){	register *p;	for(p = &u.u_utime; p  < &u.u_utime+6;) {		suword(u.u_arg[0], *p++);		u.u_arg[0] =+ 2;	}}profil(){	u.u_prof[0] = u.u_arg[0] & ~1;	/* base of sample buf */	u.u_prof[1] = u.u_arg[1];	/* size of same */	u.u_prof[2] = u.u_arg[2];	/* pc offset */	u.u_prof[3] = (u.u_arg[3]>>1) & 077777; /* pc scale */}