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/*

 *  linux/kernel/sys.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 */

#include <linux/config.h>

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/kernel.h>

#include <linux/times.h>

#include <linux/utsname.h>

#include <linux/param.h>

#include <linux/resource.h>

#include <linux/signal.h>

#include <linux/string.h>

#include <linux/ptrace.h>

#include <linux/stat.h>

#include <linux/mman.h>

#include <linux/mm.h>

#include <linux/fcntl.h>

#include <linux/acct.h>

#include <linux/tty.h>

#if defined(CONFIG_APM) && defined(CONFIG_APM_POWER_OFF)

#include <linux/apm_bios.h>

#endif

#include <asm/segment.h>

#include <asm/io.h>

/*

 * this indicates whether you can reboot with ctrl-alt-del: the default is yes

 */

int C_A_D = 1;

extern void adjust_clock(void);

extern void DAC960_Finalize(void);

extern void gdth_halt(void);

asmlinkage int sys_ni_syscall(void)

{

        return -ENOSYS;

}

static int proc_sel(struct task_struct *p, int which, int who)

{

        if(p->pid)

        {

                switch (which) {

                        case PRIO_PROCESS:

                                if (!who && p == current)

                                        return 1;

                                return(p->pid == who);

                        case PRIO_PGRP:

                                if (!who)

                                        who = current->pgrp;

                                return(p->pgrp == who);

                        case PRIO_USER:

                                if (!who)

                                        who = current->uid;

                                return(p->uid == who);

                }

        }

        return 0;

}

asmlinkage int sys_setpriority(int which, int who, int niceval)

{

        struct task_struct *p;

        int error = ESRCH;

        unsigned int priority;

        if (which > 2 || which < 0)

                return -EINVAL;

        /* normalize: avoid signed division (rounding problems) */

        priority = niceval;

        if (niceval < 0)

                priority = -niceval;

        if (priority > 20)

                priority = 20;

        priority = (priority * DEF_PRIORITY + 10) / 20 + DEF_PRIORITY;

        if (niceval >= 0) {

                priority = 2*DEF_PRIORITY - priority;

                if (!priority)

                        priority = 1;

        }

        for_each_task(p) {

                if (!proc_sel(p, which, who))

                        continue;

                if (p->uid != current->euid &&

                        p->uid != current->uid && !suser()) {

                        error = EPERM;

                        continue;

                }

                if (error == ESRCH)

                        error = 0;

                if (priority > p->priority && !suser())

                        error = EACCES;

                else

                        p->priority = priority;

        }

        return -error;

}

/*

 * Ugh. To avoid negative return values, "getpriority()" will

 * not return the normal nice-value, but a value that has been

 * offset by 20 (ie it returns 0..40 instead of -20..20)

 */

asmlinkage int sys_getpriority(int which, int who)

{

        struct task_struct *p;

        long max_prio = -ESRCH;

        if (which > 2 || which < 0)

                return -EINVAL;

        for_each_task (p) {

                if (!proc_sel(p, which, who))

                        continue;

                if (p->priority > max_prio)

                        max_prio = p->priority;

        }

        /* scale the priority from timeslice to 0..40 */

        if (max_prio > 0)

                max_prio = (max_prio * 20 + DEF_PRIORITY/2) / DEF_PRIORITY;

        return max_prio;

}

#ifndef __alpha__

/*

 * Why do these exist?  Binary compatibility with some other standard?

 * If so, maybe they should be moved into the appropriate arch

 * directory.

 */

asmlinkage int sys_profil(void)

{

        return -ENOSYS;

}

asmlinkage int sys_ftime(void)

{

        return -ENOSYS;

}

asmlinkage int sys_break(void)

{

        return -ENOSYS;

}

asmlinkage int sys_stty(void)

{

        return -ENOSYS;

}

asmlinkage int sys_gtty(void)

{

        return -ENOSYS;

}

asmlinkage int sys_prof(void)

{

        return -ENOSYS;

}

#endif

extern void hard_reset_now(void);

extern asmlinkage int sys_kill(int, int);

/*

 * Reboot system call: for obvious reasons only root may call it,

 * and even root needs to set up some magic numbers in the registers

 * so that some mistake won't make this reboot the whole machine.

 * You can also set the meaning of the ctrl-alt-del-key here.

 *

 * reboot doesn't sync: do that yourself before calling this.

 */

asmlinkage int sys_reboot(int magic, int magic_too, int flag)

{

        if (!suser())

                return -EPERM;

        if (magic != 0xfee1dead || magic_too != 672274793)

                return -EINVAL;

        if (flag == 0x01234567) {

#ifdef CONFIG_BLK_DEV_DAC960

                DAC960_Finalize();

#endif

#ifdef CONFIG_SCSI_GDTH

                gdth_halt();

#endif

                hard_reset_now();

        } else if (flag == 0x89ABCDEF)

                C_A_D = 1;

        else if (!flag)

                C_A_D = 0;

        else if (flag == 0xCDEF0123) {

#ifdef CONFIG_BLK_DEV_DAC960

                DAC960_Finalize();

#endif

#ifdef CONFIG_SCSI_GDTH

                gdth_halt();

#endif

                printk(KERN_EMERG "System halted\n");

                sys_kill(-1, SIGKILL);

#if defined(CONFIG_APM) && defined(CONFIG_APM_POWER_OFF)

                apm_power_off();

#endif

                do_exit(0);

        } else

                return -EINVAL;

        return (0);

}

/*

 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.

 * As it's called within an interrupt, it may NOT sync: the only choice

 * is whether to reboot at once, or just ignore the ctrl-alt-del.

 */

void ctrl_alt_del(void)

{

        if (C_A_D) {

#ifdef CONFIG_BLK_DEV_DAC960

                DAC960_Finalize();

#endif

#ifdef CONFIG_SCSI_GDTH

                gdth_halt();

#endif

                hard_reset_now();

        } else

                kill_proc(1, SIGINT, 1);

}

/*

 * Unprivileged users may change the real gid to the effective gid

 * or vice versa.  (BSD-style)

 *

 * If you set the real gid at all, or set the effective gid to a value not

 * equal to the real gid, then the saved gid is set to the new effective gid.

 *

 * This makes it possible for a setgid program to completely drop its

 * privileges, which is often a useful assertion to make when you are doing

 * a security audit over a program.

 *

 * The general idea is that a program which uses just setregid() will be

 * 100% compatible with BSD.  A program which uses just setgid() will be

 * 100% compatible with POSIX w/ Saved ID's.

 */

asmlinkage int sys_setregid(gid_t rgid, gid_t egid)

{

        int old_rgid = current->gid;

        int old_egid = current->egid;

        if (rgid != (gid_t) -1) {

                if ((old_rgid == rgid) ||

                    (current->egid==rgid) ||

                    suser())

                        current->gid = rgid;

                else

                        return(-EPERM);

        }

        if (egid != (gid_t) -1) {

                if ((old_rgid == egid) ||

                    (current->egid == egid) ||

                    (current->sgid == egid) ||

                    suser())

                        current->fsgid = current->egid = egid;

                else {

                        current->gid = old_rgid;

                        return(-EPERM);

                }

        }

        if (rgid != (gid_t) -1 ||

            (egid != (gid_t) -1 && egid != old_rgid))

                current->sgid = current->egid;

        current->fsgid = current->egid;

        if (current->egid != old_egid)

                current->dumpable = 0;

        return 0;

}

/*

 * setgid() is implemented like SysV w/ SAVED_IDS

 */

asmlinkage int sys_setgid(gid_t gid)

{

        int old_egid = current->egid;

        if (suser())

                current->gid = current->egid = current->sgid = current->fsgid = gid;

        else if ((gid == current->gid) || (gid == current->sgid))

                current->egid = current->fsgid = gid;

        else

                return -EPERM;

        if (current->egid != old_egid)

                current->dumpable = 0;

        return 0;

}

static char acct_active = 0;

static struct file acct_file;

int acct_process(long exitcode)

{

   struct acct ac;

   unsigned short fs;

   if (acct_active) {

      strncpy(ac.ac_comm, current->comm, ACCT_COMM);

      ac.ac_comm[ACCT_COMM-1] = '\0';

      ac.ac_utime = current->utime;

      ac.ac_stime = current->stime;

      ac.ac_btime = CT_TO_SECS(current->start_time) + (xtime.tv_sec - (jiffies / HZ));

      ac.ac_etime = CURRENT_TIME - ac.ac_btime;

      ac.ac_uid   = current->uid;

      ac.ac_gid   = current->gid;

      ac.ac_tty   = (current)->tty == NULL ? -1 :

          kdev_t_to_nr(current->tty->device);

      ac.ac_flag  = 0;

      if (current->flags & PF_FORKNOEXEC)

         ac.ac_flag |= AFORK;

      if (current->flags & PF_SUPERPRIV)

         ac.ac_flag |= ASU;

      if (current->flags & PF_DUMPCORE)

         ac.ac_flag |= ACORE;

      if (current->flags & PF_SIGNALED)

         ac.ac_flag |= AXSIG;

      ac.ac_minflt = current->min_flt;

      ac.ac_majflt = current->maj_flt;

      ac.ac_exitcode = exitcode;

      /* Kernel segment override */

      fs = get_fs();

      set_fs(KERNEL_DS);

      acct_file.f_op->write(acct_file.f_inode, &acct_file,

                             (char *)&ac, sizeof(struct acct));

      set_fs(fs);

   }

   return 0;

}

asmlinkage int sys_acct(const char *name)

{

   struct inode *inode = (struct inode *)0;

   char *tmp;

   int error;

   if (!suser())

      return -EPERM;

   if (name == (char *)0) {

      if (acct_active) {

         if (acct_file.f_op->release)

            acct_file.f_op->release(acct_file.f_inode, &acct_file);

         if (acct_file.f_inode != (struct inode *) 0)

            iput(acct_file.f_inode);

         acct_active = 0;

      }

      return 0;

   } else {

      if (!acct_active) {

         if ((error = getname(name, &tmp)) != 0)

            return (error);

         error = open_namei(tmp, O_RDWR, 0600, &inode, 0);

         putname(tmp);

         if (error)

            return (error);

         if (!S_ISREG(inode->i_mode)) {

            iput(inode);

            return -EACCES;

         }

         if (!inode->i_op || !inode->i_op->default_file_ops ||

             !inode->i_op->default_file_ops->write) {

            iput(inode);

            return -EIO;

         }

         acct_file.f_mode = 3;

         acct_file.f_flags = 0;

         acct_file.f_count = 1;

         acct_file.f_inode = inode;

         acct_file.f_pos = inode->i_size;

         acct_file.f_reada = 0;

         acct_file.f_op = inode->i_op->default_file_ops;

         if (acct_file.f_op->open)

            if (acct_file.f_op->open(acct_file.f_inode, &acct_file)) {

               iput(inode);

               return -EIO;

            }

         acct_active = 1;

         return 0;

      } else

         return -EBUSY;

   }

}

#ifndef __alpha__

/*

 * Why do these exist?  Binary compatibility with some other standard?

 * If so, maybe they should be moved into the appropriate arch

 * directory.

 */

asmlinkage int sys_phys(void)

{

        return -ENOSYS;

}

asmlinkage int sys_lock(void)

{

        return -ENOSYS;

}

asmlinkage int sys_mpx(void)

{

        return -ENOSYS;

}

asmlinkage int sys_ulimit(void)

{

        return -ENOSYS;

}

asmlinkage int sys_old_syscall(void)

{

        return -ENOSYS;

}

#endif

/*

 * Unprivileged users may change the real uid to the effective uid

 * or vice versa.  (BSD-style)

 *

 * If you set the real uid at all, or set the effective uid to a value not

 * equal to the real uid, then the saved uid is set to the new effective uid.

 *

 * This makes it possible for a setuid program to completely drop its

 * privileges, which is often a useful assertion to make when you are doing

 * a security audit over a program.

 *

 * The general idea is that a program which uses just setreuid() will be

 * 100% compatible with BSD.  A program which uses just setuid() will be

 * 100% compatible with POSIX w/ Saved ID's.

 */

asmlinkage int sys_setreuid(uid_t ruid, uid_t euid)

{

        int old_ruid = current->uid;

        int old_euid = current->euid;

        if (ruid != (uid_t) -1) {

                if ((old_ruid == ruid) ||

                    (current->euid==ruid) ||

                    suser())

                        current->uid = ruid;

                else

                        return(-EPERM);

        }

        if (euid != (uid_t) -1) {

                if ((old_ruid == euid) ||

                    (current->euid == euid) ||

                    (current->suid == euid) ||

                    suser())

                        current->fsuid = current->euid = euid;

                else {

                        current->uid = old_ruid;

                        return(-EPERM);

                }

        }

        if (ruid != (uid_t) -1 ||

            (euid != (uid_t) -1 && euid != old_ruid))

                current->suid = current->euid;

        current->fsuid = current->euid;

        if (current->euid != old_euid)

                current->dumpable = 0;

        return 0;

}

/*

 * setuid() is implemented like SysV w/ SAVED_IDS

 *

 * Note that SAVED_ID's is deficient in that a setuid root program

 * like sendmail, for example, cannot set its uid to be a normal

 * user and then switch back, because if you're root, setuid() sets

 * the saved uid too.  If you don't like this, blame the bright people

 * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()

 * will allow a root program to temporarily drop privileges and be able to

 * regain them by swapping the real and effective uid.

 */

asmlinkage int sys_setuid(uid_t uid)

{

        int old_euid = current->euid;

        if (suser())

                current->uid = current->euid = current->suid = current->fsuid = uid;

        else if ((uid == current->uid) || (uid == current->suid))

                current->fsuid = current->euid = uid;

        else

                return -EPERM;

        if (current->euid != old_euid)

                current->dumpable = 0;

        return(0);

}

/*

 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This

 * is used for "access()" and for the NFS daemon (letting nfsd stay at

 * whatever uid it wants to). It normally shadows "euid", except when

 * explicitly set by setfsuid() or for access..

 */

asmlinkage int sys_setfsuid(uid_t uid)

{

        int old_fsuid = current->fsuid;

        if (uid == current->uid || uid == current->euid ||

            uid == current->suid || uid == current->fsuid || suser())

                current->fsuid = uid;

        if (current->fsuid != old_fsuid)

                current->dumpable = 0;

        return old_fsuid;

}

/*

 * Samma på svenska..

 */

asmlinkage int sys_setfsgid(gid_t gid)

{

        int old_fsgid = current->fsgid;

        if (gid == current->gid || gid == current->egid ||

            gid == current->sgid || gid == current->fsgid || suser())

                current->fsgid = gid;

        if (current->fsgid != old_fsgid)

                current->dumpable = 0;

        return old_fsgid;

}

asmlinkage long sys_times(struct tms * tbuf)

{

        if (tbuf) {

                int error = verify_area(VERIFY_WRITE,tbuf,sizeof *tbuf);

                if (error)

                        return error;

                put_user(current->utime,&tbuf->tms_utime);

                put_user(current->stime,&tbuf->tms_stime);

                put_user(current->cutime,&tbuf->tms_cutime);

                put_user(current->cstime,&tbuf->tms_cstime);

        }

        return jiffies;

}

/*

 * This needs some heavy checking ...

 * I just haven't the stomach for it. I also don't fully

 * understand sessions/pgrp etc. Let somebody who does explain it.

 *

 * OK, I think I have the protection semantics right.... this is really

 * only important on a multi-user system anyway, to make sure one user

 * can't send a signal to a process owned by another.  -TYT, 12/12/91

 *

 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.

 * LBT 04.03.94

 */

asmlinkage int sys_setpgid(pid_t pid, pid_t pgid)

{

        struct task_struct * p;

        if (!pid)

                pid = current->pid;

        if (!pgid)

                pgid = pid;

        if (pgid < 0)

                return -EINVAL;

        for_each_task(p) {

                if (p->pid == pid)

                        goto found_task;

        }

        return -ESRCH;

found_task:

        if (p->p_pptr == current || p->p_opptr == current) {

                if (p->session != current->session)

                        return -EPERM;

                if (p->did_exec)

                        return -EACCES;

        } else if (p != current)

                return -ESRCH;

        if (p->leader)

                return -EPERM;

        if (pgid != pid) {

                struct task_struct * tmp;

                for_each_task (tmp) {

                        if (tmp->pgrp == pgid &&

                         tmp->session == current->session)

                                goto ok_pgid;

                }

                return -EPERM;

        }

ok_pgid:

        p->pgrp = pgid;

        return 0;

}

asmlinkage int sys_getpgid(pid_t pid)

{

        struct task_struct * p;

        if (!pid)

                return current->pgrp;

        for_each_task(p) {

                if (p->pid == pid)

                        return p->pgrp;

        }

        return -ESRCH;

}

asmlinkage int sys_getpgrp(void)

{

        return current->pgrp;

}

asmlinkage int sys_getsid(pid_t pid)

{

        struct task_struct * p;

        if (!pid)

                return current->session;

        for_each_task(p) {

                if (p->pid == pid)

                        return p->session;

        }

        return -ESRCH;

}

asmlinkage int sys_setsid(void)

{

        struct task_struct * p;

        for_each_task(p) {

                if (p->pgrp == current->pid)

                        return -EPERM;

        }

        current->leader = 1;

        current->session = current->pgrp = current->pid;

        current->tty = NULL;

        current->tty_old_pgrp = 0;

        return current->pgrp;

}

/*

 * Supplementary group ID's

 */

asmlinkage int sys_getgroups(int gidsetsize, gid_t *grouplist)

{

        int i;

        int * groups;

        /* Avoid an integer overflow on systems with 32 bit gid_t (Alpha) */

        if (gidsetsize & ~0x3FFFFFFF)

                return -EINVAL;

        groups = current->groups;

        for (i = 0 ; i < NGROUPS ; i++) {

                if (groups[i] == NOGROUP)

                        break;