523 lines
12 KiB
C
523 lines
12 KiB
C
/*
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* linux/kernel/sys.c
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*
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* (C) 1991 Linus Torvalds
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*/
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#include <errno.h>
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#include <linux/sched.h>
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#include <linux/tty.h>
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#include <linux/kernel.h>
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#include <linux/config.h>
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#include <asm/segment.h>
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#include <sys/times.h>
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#include <sys/utsname.h>
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#include <sys/param.h>
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#include <sys/resource.h>
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#include <string.h>
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/*
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* The timezone where the local system is located. Used as a default by some
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* programs who obtain this value by using gettimeofday.
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*/
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struct timezone sys_tz = { 0, 0};
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extern int session_of_pgrp(int pgrp);
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int sys_ftime()
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{
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return -ENOSYS;
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}
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int sys_break()
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{
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return -ENOSYS;
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}
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int sys_ptrace()
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{
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return -ENOSYS;
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}
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int sys_stty()
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{
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return -ENOSYS;
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}
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int sys_gtty()
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{
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return -ENOSYS;
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}
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int sys_rename()
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{
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return -ENOSYS;
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}
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int sys_prof()
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{
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return -ENOSYS;
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}
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/*
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* This is done BSD-style, with no consideration of the saved gid, except
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* that if you set the effective gid, it sets the saved gid too. This
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* makes it possible for a setgid program to completely drop its privileges,
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* which is often a useful assertion to make when you are doing a security
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* audit over a program.
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*
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* The general idea is that a program which uses just setregid() will be
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* 100% compatible with BSD. A program which uses just setgid() will be
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* 100% compatible with POSIX w/ Saved ID's.
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*/
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int sys_setregid(int rgid, int egid)
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{
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if (rgid>0) {
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if ((current->gid == rgid) ||
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suser())
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current->gid = rgid;
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else
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return(-EPERM);
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}
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if (egid>0) {
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if ((current->gid == egid) ||
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(current->egid == egid) ||
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suser()) {
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current->egid = egid;
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current->sgid = egid;
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} else
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return(-EPERM);
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}
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return 0;
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}
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/*
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* setgid() is implemeneted like SysV w/ SAVED_IDS
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*/
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int sys_setgid(int gid)
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{
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if (suser())
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current->gid = current->egid = current->sgid = gid;
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else if ((gid == current->gid) || (gid == current->sgid))
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current->egid = gid;
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else
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return -EPERM;
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return 0;
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}
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int sys_acct()
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{
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return -ENOSYS;
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}
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int sys_phys()
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{
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return -ENOSYS;
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}
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int sys_lock()
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{
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return -ENOSYS;
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}
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int sys_mpx()
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{
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return -ENOSYS;
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}
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int sys_ulimit()
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{
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return -ENOSYS;
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}
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int sys_time(long * tloc)
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{
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int i;
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i = CURRENT_TIME;
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if (tloc) {
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verify_area(tloc,4);
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put_fs_long(i,(unsigned long *)tloc);
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}
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return i;
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}
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/*
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* Unprivileged users may change the real user id to the effective uid
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* or vice versa. (BSD-style)
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*
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* When you set the effective uid, it sets the saved uid too. This
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* makes it possible for a setuid program to completely drop its privileges,
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* which is often a useful assertion to make when you are doing a security
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* audit over a program.
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*
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* The general idea is that a program which uses just setreuid() will be
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* 100% compatible with BSD. A program which uses just setuid() will be
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* 100% compatible with POSIX w/ Saved ID's.
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*/
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int sys_setreuid(int ruid, int euid)
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{
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int old_ruid = current->uid;
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if (ruid>0) {
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if ((current->euid==ruid) ||
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(old_ruid == ruid) ||
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suser())
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current->uid = ruid;
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else
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return(-EPERM);
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}
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if (euid>0) {
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if ((old_ruid == euid) ||
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(current->euid == euid) ||
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suser()) {
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current->euid = euid;
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current->suid = euid;
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} else {
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current->uid = old_ruid;
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return(-EPERM);
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}
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}
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return 0;
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}
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/*
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* setuid() is implemeneted like SysV w/ SAVED_IDS
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*
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* Note that SAVED_ID's is deficient in that a setuid root program
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* like sendmail, for example, cannot set its uid to be a normal
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* user and then switch back, because if you're root, setuid() sets
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* the saved uid too. If you don't like this, blame the bright people
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* in the POSIX commmittee and/or USG. Note that the BSD-style setreuid()
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* will allow a root program to temporarily drop privileges and be able to
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* regain them by swapping the real and effective uid.
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*/
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int sys_setuid(int uid)
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{
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if (suser())
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current->uid = current->euid = current->suid = uid;
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else if ((uid == current->uid) || (uid == current->suid))
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current->euid = uid;
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else
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return -EPERM;
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return(0);
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}
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int sys_stime(long * tptr)
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{
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if (!suser())
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return -EPERM;
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startup_time = get_fs_long((unsigned long *)tptr) - jiffies/HZ;
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jiffies_offset = 0;
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return 0;
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}
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int sys_times(struct tms * tbuf)
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{
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if (tbuf) {
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verify_area(tbuf,sizeof *tbuf);
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put_fs_long(current->utime,(unsigned long *)&tbuf->tms_utime);
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put_fs_long(current->stime,(unsigned long *)&tbuf->tms_stime);
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put_fs_long(current->cutime,(unsigned long *)&tbuf->tms_cutime);
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put_fs_long(current->cstime,(unsigned long *)&tbuf->tms_cstime);
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}
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return jiffies;
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}
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int sys_brk(unsigned long end_data_seg)
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{
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if (end_data_seg >= current->end_code &&
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end_data_seg < current->start_stack - 16384)
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current->brk = end_data_seg;
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return current->brk;
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}
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/*
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* This needs some heave checking ...
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* I just haven't get the stomach for it. I also don't fully
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* understand sessions/pgrp etc. Let somebody who does explain it.
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*
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* OK, I think I have the protection semantics right.... this is really
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* only important on a multi-user system anyway, to make sure one user
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* can't send a signal to a process owned by another. -TYT, 12/12/91
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*/
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int sys_setpgid(int pid, int pgid)
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{
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int i;
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if (!pid)
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pid = current->pid;
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if (!pgid)
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pgid = current->pid;
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if (pgid < 0)
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return -EINVAL;
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for (i=0 ; i<NR_TASKS ; i++)
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if (task[i] && (task[i]->pid == pid) &&
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((task[i]->p_pptr == current) ||
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(task[i] == current))) {
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if (task[i]->leader)
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return -EPERM;
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if ((task[i]->session != current->session) ||
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((pgid != pid) &&
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(session_of_pgrp(pgid) != current->session)))
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return -EPERM;
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task[i]->pgrp = pgid;
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return 0;
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}
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return -ESRCH;
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}
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int sys_getpgrp(void)
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{
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return current->pgrp;
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}
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int sys_setsid(void)
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{
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if (current->leader && !suser())
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return -EPERM;
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current->leader = 1;
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current->session = current->pgrp = current->pid;
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current->tty = -1;
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return current->pgrp;
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}
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/*
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* Supplementary group ID's
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*/
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int sys_getgroups(int gidsetsize, gid_t *grouplist)
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{
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int i;
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if (gidsetsize)
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verify_area(grouplist, sizeof(gid_t) * gidsetsize);
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for (i = 0; (i < NGROUPS) && (current->groups[i] != NOGROUP);
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i++, grouplist++) {
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if (gidsetsize) {
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if (i >= gidsetsize)
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return -EINVAL;
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put_fs_word(current->groups[i], (short *) grouplist);
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}
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}
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return(i);
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}
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int sys_setgroups(int gidsetsize, gid_t *grouplist)
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{
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int i;
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if (!suser())
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return -EPERM;
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if (gidsetsize > NGROUPS)
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return -EINVAL;
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for (i = 0; i < gidsetsize; i++, grouplist++) {
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current->groups[i] = get_fs_word((unsigned short *) grouplist);
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}
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if (i < NGROUPS)
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current->groups[i] = NOGROUP;
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return 0;
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}
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int in_group_p(gid_t grp)
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{
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int i;
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if (grp == current->egid)
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return 1;
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for (i = 0; i < NGROUPS; i++) {
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if (current->groups[i] == NOGROUP)
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break;
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if (current->groups[i] == grp)
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return 1;
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}
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return 0;
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}
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static struct utsname thisname = {
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UTS_SYSNAME, UTS_NODENAME, UTS_RELEASE, UTS_VERSION, UTS_MACHINE
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};
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int sys_uname(struct utsname * name)
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{
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int i;
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if (!name) return -ERROR;
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verify_area(name,sizeof *name);
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for(i=0;i<sizeof *name;i++)
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put_fs_byte(((char *) &thisname)[i],i+(char *) name);
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return 0;
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}
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/*
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* Only sethostname; gethostname can be implemented by calling uname()
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*/
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int sys_sethostname(char *name, int len)
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{
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int i;
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if (!suser())
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return -EPERM;
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if (len > MAXHOSTNAMELEN)
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return -EINVAL;
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for (i=0; i < len; i++) {
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if ((thisname.nodename[i] = get_fs_byte(name+i)) == 0)
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break;
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}
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if (thisname.nodename[i]) {
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thisname.nodename[i>MAXHOSTNAMELEN ? MAXHOSTNAMELEN : i] = 0;
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}
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return 0;
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}
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int sys_getrlimit(int resource, struct rlimit *rlim)
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{
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if (resource >= RLIM_NLIMITS)
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return -EINVAL;
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verify_area(rlim,sizeof *rlim);
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put_fs_long(current->rlim[resource].rlim_cur,
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(unsigned long *) rlim);
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put_fs_long(current->rlim[resource].rlim_max,
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((unsigned long *) rlim)+1);
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return 0;
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}
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int sys_setrlimit(int resource, struct rlimit *rlim)
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{
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struct rlimit new, *old;
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if (resource >= RLIM_NLIMITS)
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return -EINVAL;
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old = current->rlim + resource;
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new.rlim_cur = get_fs_long((unsigned long *) rlim);
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new.rlim_max = get_fs_long(((unsigned long *) rlim)+1);
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if (((new.rlim_cur > old->rlim_max) ||
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(new.rlim_max > old->rlim_max)) &&
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!suser())
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return -EPERM;
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*old = new;
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return 0;
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}
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/*
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* It would make sense to put struct rusuage in the task_struct,
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* except that would make the task_struct be *really big*. After
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* task_struct gets moved into malloc'ed memory, it would
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* make sense to do this. It will make moving the rest of the information
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* a lot simpler! (Which we're not doing right now because we're not
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* measuring them yet).
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*/
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int sys_getrusage(int who, struct rusage *ru)
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{
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struct rusage r;
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unsigned long *lp, *lpend, *dest;
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if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
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return -EINVAL;
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verify_area(ru, sizeof *ru);
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memset((char *) &r, 0, sizeof(r));
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if (who == RUSAGE_SELF) {
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r.ru_utime.tv_sec = CT_TO_SECS(current->utime);
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r.ru_utime.tv_usec = CT_TO_USECS(current->utime);
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r.ru_stime.tv_sec = CT_TO_SECS(current->stime);
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r.ru_stime.tv_usec = CT_TO_USECS(current->stime);
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} else {
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r.ru_utime.tv_sec = CT_TO_SECS(current->cutime);
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r.ru_utime.tv_usec = CT_TO_USECS(current->cutime);
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r.ru_stime.tv_sec = CT_TO_SECS(current->cstime);
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r.ru_stime.tv_usec = CT_TO_USECS(current->cstime);
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}
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lp = (unsigned long *) &r;
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lpend = (unsigned long *) (&r+1);
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dest = (unsigned long *) ru;
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for (; lp < lpend; lp++, dest++)
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put_fs_long(*lp, dest);
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return(0);
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}
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int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
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{
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if (tv) {
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verify_area(tv, sizeof *tv);
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put_fs_long(startup_time + CT_TO_SECS(jiffies+jiffies_offset),
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(unsigned long *) tv);
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put_fs_long(CT_TO_USECS(jiffies+jiffies_offset),
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((unsigned long *) tv)+1);
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}
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if (tz) {
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verify_area(tz, sizeof *tz);
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put_fs_long(sys_tz.tz_minuteswest, (unsigned long *) tz);
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put_fs_long(sys_tz.tz_dsttime, ((unsigned long *) tz)+1);
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}
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return 0;
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}
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/*
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* The first time we set the timezone, we will warp the clock so that
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* it is ticking GMT time instead of local time. Presumably,
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* if someone is setting the timezone then we are running in an
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* environment where the programs understand about timezones.
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* This should be done at boot time in the /etc/rc script, as
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* soon as possible, so that the clock can be set right. Otherwise,
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* various programs will get confused when the clock gets warped.
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*/
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int sys_settimeofday(struct timeval *tv, struct timezone *tz)
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{
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static int firsttime = 1;
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void adjust_clock();
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if (!suser())
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return -EPERM;
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if (tz) {
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sys_tz.tz_minuteswest = get_fs_long((unsigned long *) tz);
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sys_tz.tz_dsttime = get_fs_long(((unsigned long *) tz)+1);
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if (firsttime) {
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firsttime = 0;
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if (!tv)
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adjust_clock();
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}
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}
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if (tv) {
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int sec, usec;
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sec = get_fs_long((unsigned long *)tv);
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usec = get_fs_long(((unsigned long *)tv)+1);
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startup_time = sec - jiffies/HZ;
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jiffies_offset = usec * HZ / 1000000 - jiffies%HZ;
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}
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return 0;
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}
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/*
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* Adjust the time obtained from the CMOS to be GMT time instead of
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* local time.
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*
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* This is ugly, but preferable to the alternatives. Otherwise we
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* would either need to write a program to do it in /etc/rc (and risk
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* confusion if the program gets run more than once; it would also be
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* hard to make the program warp the clock precisely n hours) or
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* compile in the timezone information into the kernel. Bad, bad....
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*
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* XXX Currently does not adjust for daylight savings time. May not
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* need to do anything, depending on how smart (dumb?) the BIOS
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* is. Blast it all.... the best thing to do not depend on the CMOS
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* clock at all, but get the time via NTP or timed if you're on a
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* network.... - TYT, 1/1/92
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*/
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void adjust_clock()
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{
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startup_time += sys_tz.tz_minuteswest*60;
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}
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int sys_umask(int mask)
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{
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int old = current->umask;
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current->umask = mask & 0777;
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return (old);
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}
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