/* *  linux/kernel/sys.c * *  (C) 1991  Linus Torvalds */#include <errno.h>#include <linux/sched.h>#include <linux/tty.h>#include <linux/kernel.h>#include <asm/segment.h>#include <sys/times.h>#include <sys/utsname.h>int sys_ftime(){	return -ENOSYS;}int sys_break(){	return -ENOSYS;}int sys_ptrace(){	return -ENOSYS;}int sys_stty(){	return -ENOSYS;}int sys_gtty(){	return -ENOSYS;}int sys_rename(){	return -ENOSYS;}int sys_prof(){	return -ENOSYS;}int sys_setregid(int rgid, int egid){	if (rgid>0) {		if ((current->gid == rgid) || 		    suser())			current->gid = rgid;		else			return(-EPERM);	}	if (egid>0) {		if ((current->gid == egid) ||		    (current->egid == egid) ||		    (current->sgid == egid) ||		    suser())			current->egid = egid;		else			return(-EPERM);	}	return 0;}int sys_setgid(int gid){	return(sys_setregid(gid, gid));}int sys_acct(){	return -ENOSYS;}int sys_phys(){	return -ENOSYS;}int sys_lock(){	return -ENOSYS;}int sys_mpx(){	return -ENOSYS;}int sys_ulimit(){	return -ENOSYS;}int sys_time(long * tloc){	int i;	i = CURRENT_TIME;	if (tloc) {		verify_area(tloc,4);		put_fs_long(i,(unsigned long *)tloc);	}	return i;}/* * Unprivileged users may change the real user id to the effective uid * or vice versa. */int sys_setreuid(int ruid, int euid){	int old_ruid = current->uid;		if (ruid>0) {		if ((current->euid==ruid) ||                    (old_ruid == ruid) ||		    suser())			current->uid = ruid;		else			return(-EPERM);	}	if (euid>0) {		if ((old_ruid == euid) ||                    (current->euid == euid) ||		    suser())			current->euid = euid;		else {			current->uid = old_ruid;			return(-EPERM);		}	}	return 0;}int sys_setuid(int uid){	return(sys_setreuid(uid, uid));}int sys_stime(long * tptr){	if (!suser())		return -EPERM;	startup_time = get_fs_long((unsigned long *)tptr) - jiffies/HZ;	return 0;}int sys_times(struct tms * tbuf){	if (tbuf) {		verify_area(tbuf,sizeof *tbuf);		put_fs_long(current->utime,(unsigned long *)&tbuf->tms_utime);		put_fs_long(current->stime,(unsigned long *)&tbuf->tms_stime);		put_fs_long(current->cutime,(unsigned long *)&tbuf->tms_cutime);		put_fs_long(current->cstime,(unsigned long *)&tbuf->tms_cstime);	}	return jiffies;}int sys_brk(unsigned long end_data_seg){	if (end_data_seg >= current->end_code &&	    end_data_seg < current->start_stack - 16384)		current->brk = end_data_seg;	return current->brk;}/* * This needs some heave checking ... * I just haven't get the stomach for it. I also don't fully * understand sessions/pgrp etc. Let somebody who does explain it. */int sys_setpgid(int pid, int pgid){	int i;	if (!pid)		pid = current->pid;	if (!pgid)		pgid = current->pid;	for (i=0 ; i<NR_TASKS ; i++)		if (task[i] && task[i]->pid==pid) {			if (task[i]->leader)				return -EPERM;			if (task[i]->session != current->session)				return -EPERM;			task[i]->pgrp = pgid;			return 0;		}	return -ESRCH;}int sys_getpgrp(void){	return current->pgrp;}int sys_setsid(void){	if (current->leader && !suser())		return -EPERM;	current->leader = 1;	current->session = current->pgrp = current->pid;	current->tty = -1;	return current->pgrp;}int sys_uname(struct utsname * name){	static struct utsname thisname = {		"linux .0","nodename","release ","version ","machine "	};	int i;	if (!name) return -ERROR;	verify_area(name,sizeof *name);	for(i=0;i<sizeof *name;i++)		put_fs_byte(((char *) &thisname)[i],i+(char *) name);	return 0;}int sys_umask(int mask){	int old = current->umask;	current->umask = mask & 0777;	return (old);}