// SPDX-License-Identifier: GPL-2.0-only

  /*
   *  linux/kernel/compat.c
   *
   *  Kernel compatibililty routines for e.g. 32 bit syscall support
   *  on 64 bit kernels.
   *
   *  Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation

   */
  
  #include <linux/linkage.h>
  #include <linux/compat.h>
  #include <linux/errno.h>
  #include <linux/time.h>
  #include <linux/signal.h>
  #include <linux/sched.h>	/* for MAX_SCHEDULE_TIMEOUT */

  #include <linux/syscalls.h>
  #include <linux/unistd.h>
  #include <linux/security.h>

  #include <linux/export.h>

  #include <linux/migrate.h>

  #include <linux/posix-timers.h>

  #include <linux/times.h>

  #include <linux/ptrace.h>

  #include <linux/gfp.h>

  #include <linux/uaccess.h>

  #ifdef __ARCH_WANT_SYS_SIGPROCMASK

  /*
   * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
   * blocked set of signals to the supplied signal set
   */
  static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)

  {

  	memcpy(blocked->sig, &set, sizeof(set));
  }

  COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
  		       compat_old_sigset_t __user *, nset,
  		       compat_old_sigset_t __user *, oset)

  {
  	old_sigset_t old_set, new_set;
  	sigset_t new_blocked;
  
  	old_set = current->blocked.sig[0];
  
  	if (nset) {
  		if (get_user(new_set, nset))
  			return -EFAULT;
  		new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
  
  		new_blocked = current->blocked;
  
  		switch (how) {
  		case SIG_BLOCK:
  			sigaddsetmask(&new_blocked, new_set);
  			break;
  		case SIG_UNBLOCK:
  			sigdelsetmask(&new_blocked, new_set);
  			break;
  		case SIG_SETMASK:
  			compat_sig_setmask(&new_blocked, new_set);
  			break;
  		default:
  			return -EINVAL;
  		}
  
  		set_current_blocked(&new_blocked);
  	}
  
  	if (oset) {
  		if (put_user(old_set, oset))
  			return -EFAULT;
  	}
  
  	return 0;

  }

  #endif

  int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
  {

  	struct compat_rusage r32;
  	memset(&r32, 0, sizeof(r32));
  	r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
  	r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
  	r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
  	r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
  	r32.ru_maxrss = r->ru_maxrss;
  	r32.ru_ixrss = r->ru_ixrss;
  	r32.ru_idrss = r->ru_idrss;
  	r32.ru_isrss = r->ru_isrss;
  	r32.ru_minflt = r->ru_minflt;
  	r32.ru_majflt = r->ru_majflt;
  	r32.ru_nswap = r->ru_nswap;
  	r32.ru_inblock = r->ru_inblock;
  	r32.ru_oublock = r->ru_oublock;
  	r32.ru_msgsnd = r->ru_msgsnd;
  	r32.ru_msgrcv = r->ru_msgrcv;
  	r32.ru_nsignals = r->ru_nsignals;
  	r32.ru_nvcsw = r->ru_nvcsw;
  	r32.ru_nivcsw = r->ru_nivcsw;
  	if (copy_to_user(ru, &r32, sizeof(r32)))

  		return -EFAULT;
  	return 0;
  }

  static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,

  				    unsigned len, struct cpumask *new_mask)

  {
  	unsigned long *k;

  	if (len < cpumask_size())
  		memset(new_mask, 0, cpumask_size());
  	else if (len > cpumask_size())
  		len = cpumask_size();

  	k = cpumask_bits(new_mask);

  	return compat_get_bitmap(k, user_mask_ptr, len * 8);
  }

  COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
  		       unsigned int, len,
  		       compat_ulong_t __user *, user_mask_ptr)

  {

  	cpumask_var_t new_mask;

  	int retval;

  	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
  		return -ENOMEM;
  
  	retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);

  	if (retval)

  		goto out;

  	retval = sched_setaffinity(pid, new_mask);
  out:
  	free_cpumask_var(new_mask);
  	return retval;

  }

  COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
  		       compat_ulong_t __user *, user_mask_ptr)

  {
  	int ret;

  	cpumask_var_t mask;

  	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
  		return -EINVAL;
  	if (len & (sizeof(compat_ulong_t)-1))

  		return -EINVAL;

  	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  		return -ENOMEM;
  
  	ret = sched_getaffinity(pid, mask);

  	if (ret == 0) {

  		unsigned int retlen = min(len, cpumask_size());

  		if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
  			ret = -EFAULT;
  		else
  			ret = retlen;
  	}

  	free_cpumask_var(mask);

  	return ret;

  }

  /*
   * We currently only need the following fields from the sigevent
   * structure: sigev_value, sigev_signo, sig_notify and (sometimes
   * sigev_notify_thread_id).  The others are handled in user mode.
   * We also assume that copying sigev_value.sival_int is sufficient
   * to keep all the bits of sigev_value.sival_ptr intact.
   */
  int get_compat_sigevent(struct sigevent *event,
  		const struct compat_sigevent __user *u_event)
  {

  	memset(event, 0, sizeof(*event));

  	return (!access_ok(u_event, sizeof(*u_event)) ||

  		__get_user(event->sigev_value.sival_int,
  			&u_event->sigev_value.sival_int) ||
  		__get_user(event->sigev_signo, &u_event->sigev_signo) ||
  		__get_user(event->sigev_notify, &u_event->sigev_notify) ||
  		__get_user(event->sigev_notify_thread_id,
  			&u_event->sigev_notify_thread_id))
  		? -EFAULT : 0;
  }

  long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,

  		       unsigned long bitmap_size)
  {

  	unsigned long nr_compat_longs;
  
  	/* align bitmap up to nearest compat_long_t boundary */
  	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);

  	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);

  	if (!user_read_access_begin(umask, bitmap_size / 8))

  		return -EFAULT;

  	while (nr_compat_longs > 1) {
  		compat_ulong_t l1, l2;
  		unsafe_get_user(l1, umask++, Efault);
  		unsafe_get_user(l2, umask++, Efault);
  		*mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
  		nr_compat_longs -= 2;

  	}

  	if (nr_compat_longs)
  		unsafe_get_user(*mask, umask++, Efault);

  	user_read_access_end();

  	return 0;

  
  Efault:

  	user_read_access_end();

  	return -EFAULT;

  }
  
  long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
  		       unsigned long bitmap_size)
  {

  	unsigned long nr_compat_longs;
  
  	/* align bitmap up to nearest compat_long_t boundary */
  	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);

  	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);

  	if (!user_write_access_begin(umask, bitmap_size / 8))

  		return -EFAULT;

  	while (nr_compat_longs > 1) {
  		unsigned long m = *mask++;
  		unsafe_put_user((compat_ulong_t)m, umask++, Efault);
  		unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
  		nr_compat_longs -= 2;

  	}

  	if (nr_compat_longs)
  		unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);

  	user_write_access_end();

  	return 0;

  Efault:

  	user_write_access_end();

  	return -EFAULT;

  }

  int
  get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)

  {

  #ifdef __BIG_ENDIAN
  	compat_sigset_t v;
  	if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
  		return -EFAULT;

  	switch (_NSIG_WORDS) {

  	case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );

  		fallthrough;

  	case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );

  		fallthrough;

  	case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );

  		fallthrough;

  	case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );

  	}

  #else
  	if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
  		return -EFAULT;
  #endif
  	return 0;

  }

  EXPORT_SYMBOL_GPL(get_compat_sigset);

  /*
   * Allocate user-space memory for the duration of a single system call,
   * in order to marshall parameters inside a compat thunk.
   */
  void __user *compat_alloc_user_space(unsigned long len)
  {
  	void __user *ptr;
  
  	/* If len would occupy more than half of the entire compat space... */
  	if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
  		return NULL;
  
  	ptr = arch_compat_alloc_user_space(len);

  	if (unlikely(!access_ok(ptr, len)))

  		return NULL;
  
  	return ptr;
  }
  EXPORT_SYMBOL_GPL(compat_alloc_user_space);