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sys.c

/*
 *  linux/kernel/sys.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/highuid.h>
#include <linux/fs.h>
#include <linux/resource.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/workqueue.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/key.h>
#include <linux/times.h>
#include <linux/posix-timers.h>
#include <linux/security.h>
#include <linux/dcookies.h>
#include <linux/suspend.h>
#include <linux/tty.h>
#include <linux/signal.h>
#include <linux/cn_proc.h>
#include <linux/getcpu.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/seccomp.h>
#include <linux/cpu.h>

#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/kprobes.h>
#include <linux/user_namespace.h>

#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/unistd.h>

#ifndef SET_UNALIGN_CTL
# define SET_UNALIGN_CTL(a,b) (-EINVAL)
#endif
#ifndef GET_UNALIGN_CTL
# define GET_UNALIGN_CTL(a,b) (-EINVAL)
#endif
#ifndef SET_FPEMU_CTL
# define SET_FPEMU_CTL(a,b)   (-EINVAL)
#endif
#ifndef GET_FPEMU_CTL
# define GET_FPEMU_CTL(a,b)   (-EINVAL)
#endif
#ifndef SET_FPEXC_CTL
# define SET_FPEXC_CTL(a,b)   (-EINVAL)
#endif
#ifndef GET_FPEXC_CTL
# define GET_FPEXC_CTL(a,b)   (-EINVAL)
#endif
#ifndef GET_ENDIAN
# define GET_ENDIAN(a,b)      (-EINVAL)
#endif
#ifndef SET_ENDIAN
# define SET_ENDIAN(a,b)      (-EINVAL)
#endif

/*
 * this is where the system-wide overflow UID and GID are defined, for
 * architectures that now have 32-bit UID/GID but didn't in the past
 */

int overflowuid = DEFAULT_OVERFLOWUID;
int overflowgid = DEFAULT_OVERFLOWGID;

#ifdef CONFIG_UID16
EXPORT_SYMBOL(overflowuid);
EXPORT_SYMBOL(overflowgid);
#endif

/*
 * the same as above, but for filesystems which can only store a 16-bit
 * UID and GID. as such, this is needed on all architectures
 */

int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;

EXPORT_SYMBOL(fs_overflowuid);
EXPORT_SYMBOL(fs_overflowgid);

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

int C_A_D = 1;
struct pid *cad_pid;
EXPORT_SYMBOL(cad_pid);

/*
 * If set, this is used for preparing the system to power off.
 */

void (*pm_power_off_prepare)(void);

static int set_one_prio(struct task_struct *p, int niceval, int error)
{
      int no_nice;

      if (p->uid != current->euid &&
            p->euid != current->euid && !capable(CAP_SYS_NICE)) {
            error = -EPERM;
            goto out;
      }
      if (niceval < task_nice(p) && !can_nice(p, niceval)) {
            error = -EACCES;
            goto out;
      }
      no_nice = security_task_setnice(p, niceval);
      if (no_nice) {
            error = no_nice;
            goto out;
      }
      if (error == -ESRCH)
            error = 0;
      set_user_nice(p, niceval);
out:
      return error;
}

asmlinkage long sys_setpriority(int which, int who, int niceval)
{
      struct task_struct *g, *p;
      struct user_struct *user;
      int error = -EINVAL;
      struct pid *pgrp;

      if (which > PRIO_USER || which < PRIO_PROCESS)
            goto out;

      /* normalize: avoid signed division (rounding problems) */
      error = -ESRCH;
      if (niceval < -20)
            niceval = -20;
      if (niceval > 19)
            niceval = 19;

      read_lock(&tasklist_lock);
      switch (which) {
            case PRIO_PROCESS:
                  if (who)
                        p = find_task_by_vpid(who);
                  else
                        p = current;
                  if (p)
                        error = set_one_prio(p, niceval, error);
                  break;
            case PRIO_PGRP:
                  if (who)
                        pgrp = find_vpid(who);
                  else
                        pgrp = task_pgrp(current);
                  do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
                        error = set_one_prio(p, niceval, error);
                  } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
                  break;
            case PRIO_USER:
                  user = current->user;
                  if (!who)
                        who = current->uid;
                  else
                        if ((who != current->uid) && !(user = find_user(who)))
                              goto out_unlock;  /* No processes for this user */

                  do_each_thread(g, p)
                        if (p->uid == who)
                              error = set_one_prio(p, niceval, error);
                  while_each_thread(g, p);
                  if (who != current->uid)
                        free_uid(user);         /* For find_user() */
                  break;
      }
out_unlock:
      read_unlock(&tasklist_lock);
out:
      return error;
}

/*
 * Ugh. To avoid negative return values, "getpriority()" will
 * not return the normal nice-value, but a negated value that
 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 * to stay compatible.
 */
asmlinkage long sys_getpriority(int which, int who)
{
      struct task_struct *g, *p;
      struct user_struct *user;
      long niceval, retval = -ESRCH;
      struct pid *pgrp;

      if (which > PRIO_USER || which < PRIO_PROCESS)
            return -EINVAL;

      read_lock(&tasklist_lock);
      switch (which) {
            case PRIO_PROCESS:
                  if (who)
                        p = find_task_by_vpid(who);
                  else
                        p = current;
                  if (p) {
                        niceval = 20 - task_nice(p);
                        if (niceval > retval)
                              retval = niceval;
                  }
                  break;
            case PRIO_PGRP:
                  if (who)
                        pgrp = find_vpid(who);
                  else
                        pgrp = task_pgrp(current);
                  do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
                        niceval = 20 - task_nice(p);
                        if (niceval > retval)
                              retval = niceval;
                  } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
                  break;
            case PRIO_USER:
                  user = current->user;
                  if (!who)
                        who = current->uid;
                  else
                        if ((who != current->uid) && !(user = find_user(who)))
                              goto out_unlock;  /* No processes for this user */

                  do_each_thread(g, p)
                        if (p->uid == who) {
                              niceval = 20 - task_nice(p);
                              if (niceval > retval)
                                    retval = niceval;
                        }
                  while_each_thread(g, p);
                  if (who != current->uid)
                        free_uid(user);         /* for find_user() */
                  break;
      }
out_unlock:
      read_unlock(&tasklist_lock);

      return retval;
}

/**
 *    emergency_restart - reboot the system
 *
 *    Without shutting down any hardware or taking any locks
 *    reboot the system.  This is called when we know we are in
 *    trouble so this is our best effort to reboot.  This is
 *    safe to call in interrupt context.
 */
void emergency_restart(void)
{
      machine_emergency_restart();
}
EXPORT_SYMBOL_GPL(emergency_restart);

static void kernel_restart_prepare(char *cmd)
{
      blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
      system_state = SYSTEM_RESTART;
      device_shutdown();
      sysdev_shutdown();
}

/**
 *    kernel_restart - reboot the system
 *    @cmd: pointer to buffer containing command to execute for restart
 *          or %NULL
 *
 *    Shutdown everything and perform a clean reboot.
 *    This is not safe to call in interrupt context.
 */
void kernel_restart(char *cmd)
{
      kernel_restart_prepare(cmd);
      if (!cmd)
            printk(KERN_EMERG "Restarting system.\n");
      else
            printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
      machine_restart(cmd);
}
EXPORT_SYMBOL_GPL(kernel_restart);

/**
 *    kernel_kexec - reboot the system
 *
 *    Move into place and start executing a preloaded standalone
 *    executable.  If nothing was preloaded return an error.
 */
static void kernel_kexec(void)
{
#ifdef CONFIG_KEXEC
      struct kimage *image;
      image = xchg(&kexec_image, NULL);
      if (!image)
            return;
      kernel_restart_prepare(NULL);
      printk(KERN_EMERG "Starting new kernel\n");
      machine_shutdown();
      machine_kexec(image);
#endif
}

void kernel_shutdown_prepare(enum system_states state)
{
      blocking_notifier_call_chain(&reboot_notifier_list,
            (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
      system_state = state;
      device_shutdown();
}
/**
 *    kernel_halt - halt the system
 *
 *    Shutdown everything and perform a clean system halt.
 */
void kernel_halt(void)
{
      kernel_shutdown_prepare(SYSTEM_HALT);
      sysdev_shutdown();
      printk(KERN_EMERG "System halted.\n");
      machine_halt();
}

EXPORT_SYMBOL_GPL(kernel_halt);

/**
 *    kernel_power_off - power_off the system
 *
 *    Shutdown everything and perform a clean system power_off.
 */
void kernel_power_off(void)
{
      kernel_shutdown_prepare(SYSTEM_POWER_OFF);
      if (pm_power_off_prepare)
            pm_power_off_prepare();
      disable_nonboot_cpus();
      sysdev_shutdown();
      printk(KERN_EMERG "Power down.\n");
      machine_power_off();
}
EXPORT_SYMBOL_GPL(kernel_power_off);
/*
 * 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 long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
{
      char buffer[256];

      /* We only trust the superuser with rebooting the system. */
      if (!capable(CAP_SYS_BOOT))
            return -EPERM;

      /* For safety, we require "magic" arguments. */
      if (magic1 != LINUX_REBOOT_MAGIC1 ||
          (magic2 != LINUX_REBOOT_MAGIC2 &&
                      magic2 != LINUX_REBOOT_MAGIC2A &&
                  magic2 != LINUX_REBOOT_MAGIC2B &&
                      magic2 != LINUX_REBOOT_MAGIC2C))
            return -EINVAL;

      /* Instead of trying to make the power_off code look like
       * halt when pm_power_off is not set do it the easy way.
       */
      if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
            cmd = LINUX_REBOOT_CMD_HALT;

      lock_kernel();
      switch (cmd) {
      case LINUX_REBOOT_CMD_RESTART:
            kernel_restart(NULL);
            break;

      case LINUX_REBOOT_CMD_CAD_ON:
            C_A_D = 1;
            break;

      case LINUX_REBOOT_CMD_CAD_OFF:
            C_A_D = 0;
            break;

      case LINUX_REBOOT_CMD_HALT:
            kernel_halt();
            unlock_kernel();
            do_exit(0);
            break;

      case LINUX_REBOOT_CMD_POWER_OFF:
            kernel_power_off();
            unlock_kernel();
            do_exit(0);
            break;

      case LINUX_REBOOT_CMD_RESTART2:
            if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
                  unlock_kernel();
                  return -EFAULT;
            }
            buffer[sizeof(buffer) - 1] = '\0';

            kernel_restart(buffer);
            break;

      case LINUX_REBOOT_CMD_KEXEC:
            kernel_kexec();
            unlock_kernel();
            return -EINVAL;

#ifdef CONFIG_HIBERNATION
      case LINUX_REBOOT_CMD_SW_SUSPEND:
            {
                  int ret = hibernate();
                  unlock_kernel();
                  return ret;
            }
#endif

      default:
            unlock_kernel();
            return -EINVAL;
      }
      unlock_kernel();
      return 0;
}

static void deferred_cad(struct work_struct *dummy)
{
      kernel_restart(NULL);
}

/*
 * 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)
{
      static DECLARE_WORK(cad_work, deferred_cad);

      if (C_A_D)
            schedule_work(&cad_work);
      else
            kill_cad_pid(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 with saved IDs. 
 *
 * SMP: There are not races, the GIDs are checked only by filesystem
 *      operations (as far as semantic preservation is concerned).
 */
asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
{
      int old_rgid = current->gid;
      int old_egid = current->egid;
      int new_rgid = old_rgid;
      int new_egid = old_egid;
      int retval;

      retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
      if (retval)
            return retval;

      if (rgid != (gid_t) -1) {
            if ((old_rgid == rgid) ||
                (current->egid==rgid) ||
                capable(CAP_SETGID))
                  new_rgid = rgid;
            else
                  return -EPERM;
      }
      if (egid != (gid_t) -1) {
            if ((old_rgid == egid) ||
                (current->egid == egid) ||
                (current->sgid == egid) ||
                capable(CAP_SETGID))
                  new_egid = egid;
            else
                  return -EPERM;
      }
      if (new_egid != old_egid) {
            set_dumpable(current->mm, suid_dumpable);
            smp_wmb();
      }
      if (rgid != (gid_t) -1 ||
          (egid != (gid_t) -1 && egid != old_rgid))
            current->sgid = new_egid;
      current->fsgid = new_egid;
      current->egid = new_egid;
      current->gid = new_rgid;
      key_fsgid_changed(current);
      proc_id_connector(current, PROC_EVENT_GID);
      return 0;
}

/*
 * setgid() is implemented like SysV w/ SAVED_IDS 
 *
 * SMP: Same implicit races as above.
 */
asmlinkage long sys_setgid(gid_t gid)
{
      int old_egid = current->egid;
      int retval;

      retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
      if (retval)
            return retval;

      if (capable(CAP_SETGID)) {
            if (old_egid != gid) {
                  set_dumpable(current->mm, suid_dumpable);
                  smp_wmb();
            }
            current->gid = current->egid = current->sgid = current->fsgid = gid;
      } else if ((gid == current->gid) || (gid == current->sgid)) {
            if (old_egid != gid) {
                  set_dumpable(current->mm, suid_dumpable);
                  smp_wmb();
            }
            current->egid = current->fsgid = gid;
      }
      else
            return -EPERM;

      key_fsgid_changed(current);
      proc_id_connector(current, PROC_EVENT_GID);
      return 0;
}
  
static int set_user(uid_t new_ruid, int dumpclear)
{
      struct user_struct *new_user;

      new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
      if (!new_user)
            return -EAGAIN;

      if (atomic_read(&new_user->processes) >=
                        current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
                  new_user != current->nsproxy->user_ns->root_user) {
            free_uid(new_user);
            return -EAGAIN;
      }

      switch_uid(new_user);

      if (dumpclear) {
            set_dumpable(current->mm, suid_dumpable);
            smp_wmb();
      }
      current->uid = new_ruid;
      return 0;
}

/*
 * 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 with saved IDs. 
 */
asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
{
      int old_ruid, old_euid, old_suid, new_ruid, new_euid;
      int retval;

      retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
      if (retval)
            return retval;

      new_ruid = old_ruid = current->uid;
      new_euid = old_euid = current->euid;
      old_suid = current->suid;

      if (ruid != (uid_t) -1) {
            new_ruid = ruid;
            if ((old_ruid != ruid) &&
                (current->euid != ruid) &&
                !capable(CAP_SETUID))
                  return -EPERM;
      }

      if (euid != (uid_t) -1) {
            new_euid = euid;
            if ((old_ruid != euid) &&
                (current->euid != euid) &&
                (current->suid != euid) &&
                !capable(CAP_SETUID))
                  return -EPERM;
      }

      if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
            return -EAGAIN;

      if (new_euid != old_euid) {
            set_dumpable(current->mm, suid_dumpable);
            smp_wmb();
      }
      current->fsuid = current->euid = new_euid;
      if (ruid != (uid_t) -1 ||
          (euid != (uid_t) -1 && euid != old_ruid))
            current->suid = current->euid;
      current->fsuid = current->euid;

      key_fsuid_changed(current);
      proc_id_connector(current, PROC_EVENT_UID);

      return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
}


            
/*
 * setuid() is implemented like SysV with 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 long sys_setuid(uid_t uid)
{
      int old_euid = current->euid;
      int old_ruid, old_suid, new_suid;
      int retval;

      retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
      if (retval)
            return retval;

      old_ruid = current->uid;
      old_suid = current->suid;
      new_suid = old_suid;
      
      if (capable(CAP_SETUID)) {
            if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
                  return -EAGAIN;
            new_suid = uid;
      } else if ((uid != current->uid) && (uid != new_suid))
            return -EPERM;

      if (old_euid != uid) {
            set_dumpable(current->mm, suid_dumpable);
            smp_wmb();
      }
      current->fsuid = current->euid = uid;
      current->suid = new_suid;

      key_fsuid_changed(current);
      proc_id_connector(current, PROC_EVENT_UID);

      return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
}


/*
 * This function implements a generic ability to update ruid, euid,
 * and suid.  This allows you to implement the 4.4 compatible seteuid().
 */
asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
{
      int old_ruid = current->uid;
      int old_euid = current->euid;
      int old_suid = current->suid;
      int retval;

      retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
      if (retval)
            return retval;

      if (!capable(CAP_SETUID)) {
            if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
                (ruid != current->euid) && (ruid != current->suid))
                  return -EPERM;
            if ((euid != (uid_t) -1) && (euid != current->uid) &&
                (euid != current->euid) && (euid != current->suid))
                  return -EPERM;
            if ((suid != (uid_t) -1) && (suid != current->uid) &&
                (suid != current->euid) && (suid != current->suid))
                  return -EPERM;
      }
      if (ruid != (uid_t) -1) {
            if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
                  return -EAGAIN;
      }
      if (euid != (uid_t) -1) {
            if (euid != current->euid) {
                  set_dumpable(current->mm, suid_dumpable);
                  smp_wmb();
            }
            current->euid = euid;
      }
      current->fsuid = current->euid;
      if (suid != (uid_t) -1)
            current->suid = suid;

      key_fsuid_changed(current);
      proc_id_connector(current, PROC_EVENT_UID);

      return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
}

asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
{
      int retval;

      if (!(retval = put_user(current->uid, ruid)) &&
          !(retval = put_user(current->euid, euid)))
            retval = put_user(current->suid, suid);

      return retval;
}

/*
 * Same as above, but for rgid, egid, sgid.
 */
asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
{
      int retval;

      retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
      if (retval)
            return retval;

      if (!capable(CAP_SETGID)) {
            if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
                (rgid != current->egid) && (rgid != current->sgid))
                  return -EPERM;
            if ((egid != (gid_t) -1) && (egid != current->gid) &&
                (egid != current->egid) && (egid != current->sgid))
                  return -EPERM;
            if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
                (sgid != current->egid) && (sgid != current->sgid))
                  return -EPERM;
      }
      if (egid != (gid_t) -1) {
            if (egid != current->egid) {
                  set_dumpable(current->mm, suid_dumpable);
                  smp_wmb();
            }
            current->egid = egid;
      }
      current->fsgid = current->egid;
      if (rgid != (gid_t) -1)
            current->gid = rgid;
      if (sgid != (gid_t) -1)
            current->sgid = sgid;

      key_fsgid_changed(current);
      proc_id_connector(current, PROC_EVENT_GID);
      return 0;
}

asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
{
      int retval;

      if (!(retval = put_user(current->gid, rgid)) &&
          !(retval = put_user(current->egid, egid)))
            retval = put_user(current->sgid, sgid);

      return retval;
}


/*
 * "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 long sys_setfsuid(uid_t uid)
{
      int old_fsuid;

      old_fsuid = current->fsuid;
      if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
            return old_fsuid;

      if (uid == current->uid || uid == current->euid ||
          uid == current->suid || uid == current->fsuid || 
          capable(CAP_SETUID)) {
            if (uid != old_fsuid) {
                  set_dumpable(current->mm, suid_dumpable);
                  smp_wmb();
            }
            current->fsuid = uid;
      }

      key_fsuid_changed(current);
      proc_id_connector(current, PROC_EVENT_UID);

      security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);

      return old_fsuid;
}

/*
 * Samma på svenska..
 */
asmlinkage long sys_setfsgid(gid_t gid)
{
      int old_fsgid;

      old_fsgid = current->fsgid;
      if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
            return old_fsgid;

      if (gid == current->gid || gid == current->egid ||
          gid == current->sgid || gid == current->fsgid || 
          capable(CAP_SETGID)) {
            if (gid != old_fsgid) {
                  set_dumpable(current->mm, suid_dumpable);
                  smp_wmb();
            }
            current->fsgid = gid;
            key_fsgid_changed(current);
            proc_id_connector(current, PROC_EVENT_GID);
      }
      return old_fsgid;
}

asmlinkage long sys_times(struct tms __user * tbuf)
{
      /*
       *    In the SMP world we might just be unlucky and have one of
       *    the times increment as we use it. Since the value is an
       *    atomically safe type this is just fine. Conceptually its
       *    as if the syscall took an instant longer to occur.
       */
      if (tbuf) {
            struct tms tmp;
            struct task_struct *tsk = current;
            struct task_struct *t;
            cputime_t utime, stime, cutime, cstime;

            spin_lock_irq(&tsk->sighand->siglock);
            utime = tsk->signal->utime;
            stime = tsk->signal->stime;
            t = tsk;
            do {
                  utime = cputime_add(utime, t->utime);
                  stime = cputime_add(stime, t->stime);
                  t = next_thread(t);
            } while (t != tsk);

            cutime = tsk->signal->cutime;
            cstime = tsk->signal->cstime;
            spin_unlock_irq(&tsk->sighand->siglock);

            tmp.tms_utime = cputime_to_clock_t(utime);
            tmp.tms_stime = cputime_to_clock_t(stime);
            tmp.tms_cutime = cputime_to_clock_t(cutime);
            tmp.tms_cstime = cputime_to_clock_t(cstime);
            if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
                  return -EFAULT;
      }
      return (long) jiffies_64_to_clock_t(get_jiffies_64());
}

/*
 * 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 long sys_setpgid(pid_t pid, pid_t pgid)
{
      struct task_struct *p;
      struct task_struct *group_leader = current->group_leader;
      int err = -EINVAL;
      struct pid_namespace *ns;

      if (!pid)
            pid = task_pid_vnr(group_leader);
      if (!pgid)
            pgid = pid;
      if (pgid < 0)
            return -EINVAL;

      /* From this point forward we keep holding onto the tasklist lock
       * so that our parent does not change from under us. -DaveM
       */
      ns = current->nsproxy->pid_ns;

      write_lock_irq(&tasklist_lock);

      err = -ESRCH;
      p = find_task_by_pid_ns(pid, ns);
      if (!p)
            goto out;

      err = -EINVAL;
      if (!thread_group_leader(p))
            goto out;

      if (p->real_parent->tgid == group_leader->tgid) {
            err = -EPERM;
            if (task_session(p) != task_session(group_leader))
                  goto out;
            err = -EACCES;
            if (p->did_exec)
                  goto out;
      } else {
            err = -ESRCH;
            if (p != group_leader)
                  goto out;
      }

      err = -EPERM;
      if (p->signal->leader)
            goto out;

      if (pgid != pid) {
            struct task_struct *g;

            g = find_task_by_pid_type_ns(PIDTYPE_PGID, pgid, ns);
            if (!g || task_session(g) != task_session(group_leader))
                  goto out;
      }

      err = security_task_setpgid(p, pgid);
      if (err)
            goto out;

      if (task_pgrp_nr_ns(p, ns) != pgid) {
            struct pid *pid;

            detach_pid(p, PIDTYPE_PGID);
            pid = find_vpid(pgid);
            attach_pid(p, PIDTYPE_PGID, pid);
            set_task_pgrp(p, pid_nr(pid));
      }

      err = 0;
out:
      /* All paths lead to here, thus we are safe. -DaveM */
      write_unlock_irq(&tasklist_lock);
      return err;
}

asmlinkage long sys_getpgid(pid_t pid)
{
      if (!pid)
            return task_pgrp_vnr(current);
      else {
            int retval;
            struct task_struct *p;
            struct pid_namespace *ns;

            ns = current->nsproxy->pid_ns;

            read_lock(&tasklist_lock);
            p = find_task_by_pid_ns(pid, ns);
            retval = -ESRCH;
            if (p) {
                  retval = security_task_getpgid(p);
                  if (!retval)
                        retval = task_pgrp_nr_ns(p, ns);
            }
            read_unlock(&tasklist_lock);
            return retval;
      }
}

#ifdef __ARCH_WANT_SYS_GETPGRP

asmlinkage long sys_getpgrp(void)
{
      /* SMP - assuming writes are word atomic this is fine */
      return task_pgrp_vnr(current);
}

#endif

asmlinkage long sys_getsid(pid_t pid)
{
      if (!pid)
            return task_session_vnr(current);
      else {
            int retval;
            struct task_struct *p;
            struct pid_namespace *ns;

            ns = current->nsproxy->pid_ns;

            read_lock(&tasklist_lock);
            p = find_task_by_pid_ns(pid, ns);
            retval = -ESRCH;
            if (p) {
                  retval = security_task_getsid(p);
                  if (!retval)
                        retval = task_session_nr_ns(p, ns);
            }
            read_unlock(&tasklist_lock);
            return retval;
      }
}

asmlinkage long sys_setsid(void)
{
      struct task_struct *group_leader = current->group_leader;
      pid_t session;
      int err = -EPERM;

      write_lock_irq(&tasklist_lock);

      /* Fail if I am already a session leader */
      if (group_leader->signal->leader)
            goto out;

      session = group_leader->pid;
      /* Fail if a process group id already exists that equals the
       * proposed session id.
       *
       * Don't check if session id == 1 because kernel threads use this
       * session id and so the check will always fail and make it so
       * init cannot successfully call setsid.
       */
      if (session > 1 && find_task_by_pid_type_ns(PIDTYPE_PGID,
                        session, &init_pid_ns))
            goto out;

      group_leader->signal->leader = 1;
      __set_special_pids(session, session);

      spin_lock(&group_leader->sighand->siglock);
      group_leader->signal->tty = NULL;
      spin_unlock(&group_leader->sighand->siglock);

      err = task_pgrp_vnr(group_leader);
out:
      write_unlock_irq(&tasklist_lock);
      return err;
}

/*
 * Supplementary group IDs
 */

/* init to 2 - one for init_task, one to ensure it is never freed */
struct group_info init_groups = { .usage = ATOMIC_INIT(2) };

struct group_info *groups_alloc(int gidsetsize)
{
      struct group_info *group_info;
      int nblocks;
      int i;

      nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
      /* Make sure we always allocate at least one indirect block pointer */
      nblocks = nblocks ? : 1;
      group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
      if (!group_info)
            return NULL;
      group_info->ngroups = gidsetsize;
      group_info->nblocks = nblocks;
      atomic_set(&group_info->usage, 1);

      if (gidsetsize <= NGROUPS_SMALL)
            group_info->blocks[0] = group_info->small_block;
      else {
            for (i = 0; i < nblocks; i++) {
                  gid_t *b;
                  b = (void *)__get_free_page(GFP_USER);
                  if (!b)
                        goto out_undo_partial_alloc;
                  group_info->blocks[i] = b;
            }
      }
      return group_info;

out_undo_partial_alloc:
      while (--i >= 0) {
            free_page((unsigned long)group_info->blocks[i]);
      }
      kfree(group_info);
      return NULL;
}

EXPORT_SYMBOL(groups_alloc);

void groups_free(struct group_info *group_info)
{
      if (group_info->blocks[0] != group_info->small_block) {
            int i;
            for (i = 0; i < group_info->nblocks; i++)
                  free_page((unsigned long)group_info->blocks[i]);
      }
      kfree(group_info);
}

EXPORT_SYMBOL(groups_free);

/* export the group_info to a user-space array */
static int groups_to_user(gid_t __user *grouplist,
    struct group_info *group_info)
{
      int i;
      int count = group_info->ngroups;

      for (i = 0; i < group_info->nblocks; i++) {
            int cp_count = min(NGROUPS_PER_BLOCK, count);
            int off = i * NGROUPS_PER_BLOCK;
            int len = cp_count * sizeof(*grouplist);

            if (copy_to_user(grouplist+off, group_info->blocks[i], len))
                  return -EFAULT;

            count -= cp_count;
      }
      return 0;
}

/* fill a group_info from a user-space array - it must be allocated already */
static int groups_from_user(struct group_info *group_info,
    gid_t __user *grouplist)
{
      int i;
      int count = group_info->ngroups;

      for (i = 0; i < group_info->nblocks; i++) {
            int cp_count = min(NGROUPS_PER_BLOCK, count);
            int off = i * NGROUPS_PER_BLOCK;
            int len = cp_count * sizeof(*grouplist);

            if (copy_from_user(group_info->blocks[i], grouplist+off, len))
                  return -EFAULT;

            count -= cp_count;
      }
      return 0;
}

/* a simple Shell sort */
static void groups_sort(struct group_info *group_info)
{
      int base, max, stride;
      int gidsetsize = group_info->ngroups;

      for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
            ; /* nothing */
      stride /= 3;

      while (stride) {
            max = gidsetsize - stride;
            for (base = 0; base < max; base++) {
                  int left = base;
                  int right = left + stride;
                  gid_t tmp = GROUP_AT(group_info, right);

                  while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
                        GROUP_AT(group_info, right) =
                            GROUP_AT(group_info, left);
                        right = left;
                        left -= stride;
                  }
                  GROUP_AT(group_info, right) = tmp;
            }
            stride /= 3;
      }
}

/* a simple bsearch */
int groups_search(struct group_info *group_info, gid_t grp)
{
      unsigned int left, right;

      if (!group_info)
            return 0;

      left = 0;
      right = group_info->ngroups;
      while (left < right) {
            unsigned int mid = (left+right)/2;
            int cmp = grp - GROUP_AT(group_info, mid);
            if (cmp > 0)
                  left = mid + 1;
            else if (cmp < 0)
                  right = mid;
            else
                  return 1;
      }
      return 0;
}

/* validate and set current->group_info */
int set_current_groups(struct group_info *group_info)
{
      int retval;
      struct group_info *old_info;

      retval = security_task_setgroups(group_info);
      if (retval)
            return retval;

      groups_sort(group_info);
      get_group_info(group_info);

      task_lock(current);
      old_info = current->group_info;
      current->group_info = group_info;
      task_unlock(current);

      put_group_info(old_info);

      return 0;
}

EXPORT_SYMBOL(set_current_groups);

asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
{
      int i = 0;

      /*
       *    SMP: Nobody else can change our grouplist. Thus we are
       *    safe.
       */

      if (gidsetsize < 0)
            return -EINVAL;

      /* no need to grab task_lock here; it cannot change */
      i = current->group_info->ngroups;
      if (gidsetsize) {
            if (i > gidsetsize) {
                  i = -EINVAL;
                  goto out;
            }
            if (groups_to_user(grouplist, current->group_info)) {
                  i = -EFAULT;
                  goto out;
            }
      }
out:
      return i;
}

/*
 *    SMP: Our groups are copy-on-write. We can set them safely
 *    without another task interfering.
 */
 
asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
{
      struct group_info *group_info;
      int retval;

      if (!capable(CAP_SETGID))
            return -EPERM;
      if ((unsigned)gidsetsize > NGROUPS_MAX)
            return -EINVAL;

      group_info = groups_alloc(gidsetsize);
      if (!group_info)
            return -ENOMEM;
      retval = groups_from_user(group_info, grouplist);
      if (retval) {
            put_group_info(group_info);
            return retval;
      }

      retval = set_current_groups(group_info);
      put_group_info(group_info);

      return retval;
}

/*
 * Check whether we're fsgid/egid or in the supplemental group..
 */
int in_group_p(gid_t grp)
{
      int retval = 1;
      if (grp != current->fsgid)
            retval = groups_search(current->group_info, grp);
      return retval;
}

EXPORT_SYMBOL(in_group_p);

int in_egroup_p(gid_t grp)
{
      int retval = 1;
      if (grp != current->egid)
            retval = groups_search(current->group_info, grp);
      return retval;
}

EXPORT_SYMBOL(in_egroup_p);

DECLARE_RWSEM(uts_sem);

EXPORT_SYMBOL(uts_sem);

asmlinkage long sys_newuname(struct new_utsname __user * name)
{
      int errno = 0;

      down_read(&uts_sem);
      if (copy_to_user(name, utsname(), sizeof *name))
            errno = -EFAULT;
      up_read(&uts_sem);
      return errno;
}

asmlinkage long sys_sethostname(char __user *name, int len)
{
      int errno;
      char tmp[__NEW_UTS_LEN];

      if (!capable(CAP_SYS_ADMIN))
            return -EPERM;
      if (len < 0 || len > __NEW_UTS_LEN)
            return -EINVAL;
      down_write(&uts_sem);
      errno = -EFAULT;
      if (!copy_from_user(tmp, name, len)) {
            memcpy(utsname()->nodename, tmp, len);
            utsname()->nodename[len] = 0;
            errno = 0;
      }
      up_write(&uts_sem);
      return errno;
}

#ifdef __ARCH_WANT_SYS_GETHOSTNAME

asmlinkage long sys_gethostname(char __user *name, int len)
{
      int i, errno;

      if (len < 0)
            return -EINVAL;
      down_read(&uts_sem);
      i = 1 + strlen(utsname()->nodename);
      if (i > len)
            i = len;
      errno = 0;
      if (copy_to_user(name, utsname()->nodename, i))
            errno = -EFAULT;
      up_read(&uts_sem);
      return errno;
}

#endif

/*
 * Only setdomainname; getdomainname can be implemented by calling
 * uname()
 */
asmlinkage long sys_setdomainname(char __user *name, int len)
{
      int errno;
      char tmp[__NEW_UTS_LEN];

      if (!capable(CAP_SYS_ADMIN))
            return -EPERM;
      if (len < 0 || len > __NEW_UTS_LEN)
            return -EINVAL;

      down_write(&uts_sem);
      errno = -EFAULT;
      if (!copy_from_user(tmp, name, len)) {
            memcpy(utsname()->domainname, tmp, len);
            utsname()->domainname[len] = 0;
            errno = 0;
      }
      up_write(&uts_sem);
      return errno;
}

asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
{
      if (resource >= RLIM_NLIMITS)
            return -EINVAL;
      else {
            struct rlimit value;
            task_lock(current->group_leader);
            value = current->signal->rlim[resource];
            task_unlock(current->group_leader);
            return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
      }
}

#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT

/*
 *    Back compatibility for getrlimit. Needed for some apps.
 */
 
asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
{
      struct rlimit x;
      if (resource >= RLIM_NLIMITS)
            return -EINVAL;

      task_lock(current->group_leader);
      x = current->signal->rlim[resource];
      task_unlock(current->group_leader);
      if (x.rlim_cur > 0x7FFFFFFF)
            x.rlim_cur = 0x7FFFFFFF;
      if (x.rlim_max > 0x7FFFFFFF)
            x.rlim_max = 0x7FFFFFFF;
      return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
}

#endif

asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
{
      struct rlimit new_rlim, *old_rlim;
      unsigned long it_prof_secs;
      int retval;

      if (resource >= RLIM_NLIMITS)
            return -EINVAL;
      if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
            return -EFAULT;
      if (new_rlim.rlim_cur > new_rlim.rlim_max)
            return -EINVAL;
      old_rlim = current->signal->rlim + resource;
      if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
          !capable(CAP_SYS_RESOURCE))
            return -EPERM;
      if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
            return -EPERM;

      retval = security_task_setrlimit(resource, &new_rlim);
      if (retval)
            return retval;

      if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
            /*
             * The caller is asking for an immediate RLIMIT_CPU
             * expiry.  But we use the zero value to mean "it was
             * never set".  So let's cheat and make it one second
             * instead
             */
            new_rlim.rlim_cur = 1;
      }

      task_lock(current->group_leader);
      *old_rlim = new_rlim;
      task_unlock(current->group_leader);

      if (resource != RLIMIT_CPU)
            goto out;

      /*
       * RLIMIT_CPU handling.   Note that the kernel fails to return an error
       * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
       * very long-standing error, and fixing it now risks breakage of
       * applications, so we live with it
       */
      if (new_rlim.rlim_cur == RLIM_INFINITY)
            goto out;

      it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
      if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
            unsigned long rlim_cur = new_rlim.rlim_cur;
            cputime_t cputime;

            cputime = secs_to_cputime(rlim_cur);
            read_lock(&tasklist_lock);
            spin_lock_irq(&current->sighand->siglock);
            set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
            spin_unlock_irq(&current->sighand->siglock);
            read_unlock(&tasklist_lock);
      }
out:
      return 0;
}

/*
 * It would make sense to put struct rusage in the task_struct,
 * except that would make the task_struct be *really big*.  After
 * task_struct gets moved into malloc'ed memory, it would
 * make sense to do this.  It will make moving the rest of the information
 * a lot simpler!  (Which we're not doing right now because we're not
 * measuring them yet).
 *
 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
 * races with threads incrementing their own counters.  But since word
 * reads are atomic, we either get new values or old values and we don't
 * care which for the sums.  We always take the siglock to protect reading
 * the c* fields from p->signal from races with exit.c updating those
 * fields when reaping, so a sample either gets all the additions of a
 * given child after it's reaped, or none so this sample is before reaping.
 *
 * Locking:
 * We need to take the siglock for CHILDEREN, SELF and BOTH
 * for  the cases current multithreaded, non-current single threaded
 * non-current multithreaded.  Thread traversal is now safe with
 * the siglock held.
 * Strictly speaking, we donot need to take the siglock if we are current and
 * single threaded,  as no one else can take our signal_struct away, no one
 * else can  reap the  children to update signal->c* counters, and no one else
 * can race with the signal-> fields. If we do not take any lock, the
 * signal-> fields could be read out of order while another thread was just
 * exiting. So we should  place a read memory barrier when we avoid the lock.
 * On the writer side,  write memory barrier is implied in  __exit_signal
 * as __exit_signal releases  the siglock spinlock after updating the signal->
 * fields. But we don't do this yet to keep things simple.
 *
 */

static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
{
      struct task_struct *t;
      unsigned long flags;
      cputime_t utime, stime;

      memset((char *) r, 0, sizeof *r);
      utime = stime = cputime_zero;

      rcu_read_lock();
      if (!lock_task_sighand(p, &flags)) {
            rcu_read_unlock();
            return;
      }

      switch (who) {
            case RUSAGE_BOTH:
            case RUSAGE_CHILDREN:
                  utime = p->signal->cutime;
                  stime = p->signal->cstime;
                  r->ru_nvcsw = p->signal->cnvcsw;
                  r->ru_nivcsw = p->signal->cnivcsw;
                  r->ru_minflt = p->signal->cmin_flt;
                  r->ru_majflt = p->signal->cmaj_flt;
                  r->ru_inblock = p->signal->cinblock;
                  r->ru_oublock = p->signal->coublock;

                  if (who == RUSAGE_CHILDREN)
                        break;

            case RUSAGE_SELF:
                  utime = cputime_add(utime, p->signal->utime);
                  stime = cputime_add(stime, p->signal->stime);
                  r->ru_nvcsw += p->signal->nvcsw;
                  r->ru_nivcsw += p->signal->nivcsw;
                  r->ru_minflt += p->signal->min_flt;
                  r->ru_majflt += p->signal->maj_flt;
                  r->ru_inblock += p->signal->inblock;
                  r->ru_oublock += p->signal->oublock;
                  t = p;
                  do {
                        utime = cputime_add(utime, t->utime);
                        stime = cputime_add(stime, t->stime);
                        r->ru_nvcsw += t->nvcsw;
                        r->ru_nivcsw += t->nivcsw;
                        r->ru_minflt += t->min_flt;
                        r->ru_majflt += t->maj_flt;
                        r->ru_inblock += task_io_get_inblock(t);
                        r->ru_oublock += task_io_get_oublock(t);
                        t = next_thread(t);
                  } while (t != p);
                  break;

            default:
                  BUG();
      }

      unlock_task_sighand(p, &flags);
      rcu_read_unlock();

      cputime_to_timeval(utime, &r->ru_utime);
      cputime_to_timeval(stime, &r->ru_stime);
}

int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
{
      struct rusage r;
      k_getrusage(p, who, &r);
      return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
}

asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
{
      if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
            return -EINVAL;
      return getrusage(current, who, ru);
}

asmlinkage long sys_umask(int mask)
{
      mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
      return mask;
}
    
asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                    unsigned long arg4, unsigned long arg5)
{
      long error;

      error = security_task_prctl(option, arg2, arg3, arg4, arg5);
      if (error)
            return error;

      switch (option) {
            case PR_SET_PDEATHSIG:
                  if (!valid_signal(arg2)) {
                        error = -EINVAL;
                        break;
                  }
                  current->pdeath_signal = arg2;
                  break;
            case PR_GET_PDEATHSIG:
                  error = put_user(current->pdeath_signal, (int __user *)arg2);
                  break;
            case PR_GET_DUMPABLE:
                  error = get_dumpable(current->mm);
                  break;
            case PR_SET_DUMPABLE:
                  if (arg2 < 0 || arg2 > 1) {
                        error = -EINVAL;
                        break;
                  }
                  set_dumpable(current->mm, arg2);
                  break;

            case PR_SET_UNALIGN:
                  error = SET_UNALIGN_CTL(current, arg2);
                  break;
            case PR_GET_UNALIGN:
                  error = GET_UNALIGN_CTL(current, arg2);
                  break;
            case PR_SET_FPEMU:
                  error = SET_FPEMU_CTL(current, arg2);
                  break;
            case PR_GET_FPEMU:
                  error = GET_FPEMU_CTL(current, arg2);
                  break;
            case PR_SET_FPEXC:
                  error = SET_FPEXC_CTL(current, arg2);
                  break;
            case PR_GET_FPEXC:
                  error = GET_FPEXC_CTL(current, arg2);
                  break;
            case PR_GET_TIMING:
                  error = PR_TIMING_STATISTICAL;
                  break;
            case PR_SET_TIMING:
                  if (arg2 == PR_TIMING_STATISTICAL)
                        error = 0;
                  else
                        error = -EINVAL;
                  break;

            case PR_GET_KEEPCAPS:
                  if (current->keep_capabilities)
                        error = 1;
                  break;
            case PR_SET_KEEPCAPS:
                  if (arg2 != 0 && arg2 != 1) {
                        error = -EINVAL;
                        break;
                  }
                  current->keep_capabilities = arg2;
                  break;
            case PR_SET_NAME: {
                  struct task_struct *me = current;
                  unsigned char ncomm[sizeof(me->comm)];

                  ncomm[sizeof(me->comm)-1] = 0;
                  if (strncpy_from_user(ncomm, (char __user *)arg2,
                                    sizeof(me->comm)-1) < 0)
                        return -EFAULT;
                  set_task_comm(me, ncomm);
                  return 0;
            }
            case PR_GET_NAME: {
                  struct task_struct *me = current;
                  unsigned char tcomm[sizeof(me->comm)];

                  get_task_comm(tcomm, me);
                  if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
                        return -EFAULT;
                  return 0;
            }
            case PR_GET_ENDIAN:
                  error = GET_ENDIAN(current, arg2);
                  break;
            case PR_SET_ENDIAN:
                  error = SET_ENDIAN(current, arg2);
                  break;

            case PR_GET_SECCOMP:
                  error = prctl_get_seccomp();
                  break;
            case PR_SET_SECCOMP:
                  error = prctl_set_seccomp(arg2);
                  break;

            default:
                  error = -EINVAL;
                  break;
      }
      return error;
}

asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
                     struct getcpu_cache __user *unused)
{
      int err = 0;
      int cpu = raw_smp_processor_id();
      if (cpup)
            err |= put_user(cpu, cpup);
      if (nodep)
            err |= put_user(cpu_to_node(cpu), nodep);
      return err ? -EFAULT : 0;
}

char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";

static void argv_cleanup(char **argv, char **envp)
{
      argv_free(argv);
}

/**
 * orderly_poweroff - Trigger an orderly system poweroff
 * @force: force poweroff if command execution fails
 *
 * This may be called from any context to trigger a system shutdown.
 * If the orderly shutdown fails, it will force an immediate shutdown.
 */
int orderly_poweroff(bool force)
{
      int argc;
      char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
      static char *envp[] = {
            "HOME=/",
            "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
            NULL
      };
      int ret = -ENOMEM;
      struct subprocess_info *info;

      if (argv == NULL) {
            printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
                   __func__, poweroff_cmd);
            goto out;
      }

      info = call_usermodehelper_setup(argv[0], argv, envp);
      if (info == NULL) {
            argv_free(argv);
            goto out;
      }

      call_usermodehelper_setcleanup(info, argv_cleanup);

      ret = call_usermodehelper_exec(info, UMH_NO_WAIT);

  out:
      if (ret && force) {
            printk(KERN_WARNING "Failed to start orderly shutdown: "
                   "forcing the issue\n");

            /* I guess this should try to kick off some daemon to
               sync and poweroff asap.  Or not even bother syncing
               if we're doing an emergency shutdown? */
            emergency_sync();
            kernel_power_off();
      }

      return ret;
}
EXPORT_SYMBOL_GPL(orderly_poweroff);

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