/*      $NetBSD: linux_misc.c,v 1.267 2024/10/01 16:41:29 riastradh Exp $       */

/*-
 * Copyright (c) 1995, 1998, 1999, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Frank van der Linden and Eric Haszlakiewicz; by Jason R. Thorpe
 * of the Numerical Aerospace Simulation Facility, NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Linux compatibility module. Try to deal with various Linux system calls.
 */

/*
 * These functions have been moved to multiarch to allow
 * selection of which machines include them to be
 * determined by the individual files.linux_<arch> files.
 *
 * Function in multiarch:
 *      linux_sys_break                 : linux_break.c
 *      linux_sys_alarm                 : linux_misc_notalpha.c
 *      linux_sys_getresgid             : linux_misc_notalpha.c
 *      linux_sys_nice                  : linux_misc_notalpha.c
 *      linux_sys_readdir               : linux_misc_notalpha.c
 *      linux_sys_setresgid             : linux_misc_notalpha.c
 *      linux_sys_time                  : linux_misc_notalpha.c
 *      linux_sys_utime                 : linux_misc_notalpha.c
 *      linux_sys_waitpid               : linux_misc_notalpha.c
 *      linux_sys_old_mmap              : linux_oldmmap.c
 *      linux_sys_oldolduname           : linux_oldolduname.c
 *      linux_sys_oldselect             : linux_oldselect.c
 *      linux_sys_olduname              : linux_olduname.c
 *      linux_sys_pipe                  : linux_pipe.c
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_misc.c,v 1.267 2024/10/01 16:41:29 riastradh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/dirent.h>
#include <sys/epoll.h>
#include <sys/eventfd.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/poll.h>
#include <sys/prot.h>
#include <sys/reboot.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/select.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/vnode.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <sys/utsname.h>
#include <sys/unistd.h>
#include <sys/vfs_syscalls.h>
#include <sys/swap.h>           /* for SWAP_ON */
#include <sys/sysctl.h>         /* for KERN_DOMAINNAME */
#include <sys/kauth.h>
#include <sys/futex.h>

#include <sys/ptrace.h>
#include <machine/ptrace.h>

#include <sys/syscall.h>
#include <sys/syscallargs.h>

#include <compat/sys/resource.h>

#include <compat/linux/common/linux_machdep.h>
#include <compat/linux/common/linux_types.h>
#include <compat/linux/common/linux_signal.h>
#include <compat/linux/common/linux_ipc.h>
#include <compat/linux/common/linux_sem.h>

#include <compat/linux/common/linux_fcntl.h>
#include <compat/linux/common/linux_mmap.h>
#include <compat/linux/common/linux_dirent.h>
#include <compat/linux/common/linux_util.h>
#include <compat/linux/common/linux_misc.h>
#include <compat/linux/common/linux_statfs.h>
#include <compat/linux/common/linux_limit.h>
#include <compat/linux/common/linux_ptrace.h>
#include <compat/linux/common/linux_reboot.h>
#include <compat/linux/common/linux_emuldata.h>
#include <compat/linux/common/linux_sched.h>

#include <compat/linux/linux_syscallargs.h>

const int linux_ptrace_request_map[] = {
        LINUX_PTRACE_TRACEME,   PT_TRACE_ME,
        LINUX_PTRACE_PEEKTEXT,  PT_READ_I,
        LINUX_PTRACE_PEEKDATA,  PT_READ_D,
        LINUX_PTRACE_POKETEXT,  PT_WRITE_I,
        LINUX_PTRACE_POKEDATA,  PT_WRITE_D,
        LINUX_PTRACE_CONT,      PT_CONTINUE,
        LINUX_PTRACE_KILL,      PT_KILL,
        LINUX_PTRACE_ATTACH,    PT_ATTACH,
        LINUX_PTRACE_DETACH,    PT_DETACH,
# ifdef PT_STEP
        LINUX_PTRACE_SINGLESTEP,        PT_STEP,
# endif
        LINUX_PTRACE_SYSCALL,   PT_SYSCALL,
        -1
};

const struct linux_mnttypes linux_fstypes[] = {
        { MOUNT_FFS,            LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_NFS,            LINUX_NFS_SUPER_MAGIC           },
        { MOUNT_MFS,            LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_MSDOS,          LINUX_MSDOS_SUPER_MAGIC         },
        { MOUNT_LFS,            LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_FDESC,          LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_NULL,           LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_OVERLAY,        LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_UMAP,           LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_KERNFS,         LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_PROCFS,         LINUX_PROC_SUPER_MAGIC          },
        { MOUNT_AFS,            LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_CD9660,         LINUX_ISOFS_SUPER_MAGIC         },
        { MOUNT_UNION,          LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_ADOSFS,         LINUX_ADFS_SUPER_MAGIC          },
        { MOUNT_EXT2FS,         LINUX_EXT2_SUPER_MAGIC          },
        { MOUNT_CFS,            LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_CODA,           LINUX_CODA_SUPER_MAGIC          },
        { MOUNT_FILECORE,       LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_NTFS,           LINUX_DEFAULT_SUPER_MAGIC       },
        { MOUNT_SMBFS,          LINUX_SMB_SUPER_MAGIC           },
        { MOUNT_PTYFS,          LINUX_DEVPTS_SUPER_MAGIC        },
        { MOUNT_TMPFS,          LINUX_TMPFS_SUPER_MAGIC         }
};
const int linux_fstypes_cnt = sizeof(linux_fstypes) / sizeof(linux_fstypes[0]);

#ifdef DEBUG_LINUX
#define DPRINTF(a, ...) uprintf(a, __VA_ARGS__)
#else
#define DPRINTF(a, ...)
#endif

/* Local linux_misc.c functions: */
static void linux_to_bsd_mmap_args(struct sys_mmap_args *,
    const struct linux_sys_mmap_args *);
static int linux_mmap(struct lwp *, const struct linux_sys_mmap_args *,
    register_t *, off_t);
static int linux_to_native_wait_options(int);

/*
 * The information on a terminated (or stopped) process needs
 * to be converted in order for Linux binaries to get a valid signal
 * number out of it.
 */
int
bsd_to_linux_wstat(int st)
{

        int sig;

        if (WIFSIGNALED(st)) {
                sig = WTERMSIG(st);
                if (sig >= 0 && sig < NSIG)
                        st= (st & ~0177) | native_to_linux_signo[sig];
        } else if (WIFSTOPPED(st)) {
                sig = WSTOPSIG(st);
                if (sig >= 0 && sig < NSIG)
                        st = (st & ~0xff00) |
                            (native_to_linux_signo[sig] << 8);
        }
        return st;
}

/*
 * wait4(2).  Passed on to the NetBSD call, surrounded by code to
 * reserve some space for a NetBSD-style wait status, and converting
 * it to what Linux wants.
 */
int
linux_sys_wait4(struct lwp *l, const struct linux_sys_wait4_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) pid;
                syscallarg(int *) status;
                syscallarg(int) options;
                syscallarg(struct rusage50 *) rusage;
        } */
        int error, status, options, linux_options, pid = SCARG(uap, pid);
        struct rusage50 ru50;
        struct rusage ru;
        proc_t *p;

        linux_options = SCARG(uap, options);
        if (linux_options & ~(LINUX_WAIT4_KNOWNFLAGS))
                return (EINVAL);

        options = linux_to_native_wait_options(linux_options);
# ifdef DIAGNOSTIC
        if (linux_options & LINUX_WNOTHREAD)
                printf("WARNING: %s: linux process %d.%d called "
                       "waitpid with __WNOTHREAD set!\n",
                       __FILE__, l->l_proc->p_pid, l->l_lid);

# endif

        error = do_sys_wait(&pid, &status, options,
            SCARG(uap, rusage) != NULL ? &ru : NULL);

        retval[0] = pid;
        if (pid == 0)
                return error;

        p = curproc;
        mutex_enter(p->p_lock);
        sigdelset(&p->p_sigpend.sp_set, SIGCHLD); /* XXXAD ksiginfo leak */
        mutex_exit(p->p_lock);

        if (SCARG(uap, rusage) != NULL) {
                rusage_to_rusage50(&ru, &ru50);
                error = copyout(&ru, SCARG(uap, rusage), sizeof(ru));
        }

        if (error == 0 && SCARG(uap, status) != NULL) {
                status = bsd_to_linux_wstat(status);
                error = copyout(&status, SCARG(uap, status), sizeof status);
        }

        return error;
}

/*
 * waitid(2).  Converting arguments to the NetBSD equivalent and
 * calling it.
 */
int
linux_sys_waitid(struct lwp *l, const struct linux_sys_waitid_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) idtype;
                syscallarg(id_t) id;
                syscallarg(linux_siginfo_t *) infop;
                syscallarg(int) options;
                syscallarg(struct rusage50 *) rusage;
        } */
        int error, linux_options, options, linux_idtype, status;
        pid_t pid;
        idtype_t idtype;
        id_t id;
        siginfo_t info;
        linux_siginfo_t linux_info;
        struct wrusage wru;
        struct rusage50 ru50;

        linux_idtype = SCARG(uap, idtype);
        switch (linux_idtype) {
        case LINUX_P_ALL:
                idtype = P_ALL;
                break;
        case LINUX_P_PID:
                idtype = P_PID;
                break;
        case LINUX_P_PGID:
                idtype = P_PGID;
                break;
        case LINUX_P_PIDFD:
                return EOPNOTSUPP;
        default:
                return EINVAL;
        }

        linux_options = SCARG(uap, options);
        if (linux_options & ~(LINUX_WAITID_KNOWNFLAGS))
                return EINVAL;

        options = linux_to_native_wait_options(linux_options);
        id = SCARG(uap, id);

        error = do_sys_waitid(idtype, id, &pid, &status, options, &wru, &info);
        if (pid == 0 && options & WNOHANG) {
                info.si_signo = 0;
                info.si_pid = 0;
        }

        if (error == 0 && SCARG(uap, infop) != NULL) {
                /* POSIX says that this NULL check is a bug, but Linux does this. */
                native_to_linux_siginfo(&linux_info, &info._info);
                error = copyout(&linux_info, SCARG(uap, infop), sizeof(linux_info));
        }

        if (error == 0 && SCARG(uap, rusage) != NULL) {
                rusage_to_rusage50(&wru.wru_children, &ru50);
                error = copyout(&ru50, SCARG(uap, rusage), sizeof(ru50));
        }

        return error;
}

/*
 * Convert the options argument for wait4(2) and waitid(2) from what
 * Linux wants to what NetBSD wants.
 */
static int
linux_to_native_wait_options(int linux_options)
{
        int options = 0;

        if (linux_options & LINUX_WNOHANG)
                options |= WNOHANG;
        if (linux_options & LINUX_WUNTRACED)
                options |= WUNTRACED;
        if (linux_options & LINUX_WEXITED)
                options |= WEXITED;
        if (linux_options & LINUX_WCONTINUED)
                options |= WCONTINUED;
        if (linux_options & LINUX_WNOWAIT)
                options |= WNOWAIT;
        if (linux_options & LINUX_WALL)
                options |= WALLSIG;
        if (linux_options & LINUX_WCLONE)
                options |= WALTSIG;

        return options;
}

/*
 * Linux brk(2).  Like native, but always return the new break value.
 */
int
linux_sys_brk(struct lwp *l, const struct linux_sys_brk_args *uap, register_t *retval)
{
        /* {
                syscallarg(char *) nsize;
        } */
        struct proc *p = l->l_proc;
        struct vmspace *vm = p->p_vmspace;
        struct sys_obreak_args oba;

        SCARG(&oba, nsize) = SCARG(uap, nsize);

        (void) sys_obreak(l, &oba, retval);
        retval[0] = (register_t)((char *)vm->vm_daddr + ptoa(vm->vm_dsize));
        return 0;
}

/*
 * Implement the fs stat functions. Straightforward.
 */
int
linux_sys_statfs(struct lwp *l, const struct linux_sys_statfs_args *uap, register_t *retval)
{
        /* {
                syscallarg(const char *) path;
                syscallarg(struct linux_statfs *) sp;
        } */
        struct statvfs *sb;
        struct linux_statfs ltmp;
        int error;

        sb = STATVFSBUF_GET();
        error = do_sys_pstatvfs(l, SCARG(uap, path), ST_WAIT, sb);
        if (error == 0) {
                bsd_to_linux_statfs(sb, &ltmp);
                error = copyout(&ltmp, SCARG(uap, sp), sizeof ltmp);
        }
        STATVFSBUF_PUT(sb);

        return error;
}

int
linux_sys_fstatfs(struct lwp *l, const struct linux_sys_fstatfs_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) fd;
                syscallarg(struct linux_statfs *) sp;
        } */
        struct statvfs *sb;
        struct linux_statfs ltmp;
        int error;

        sb = STATVFSBUF_GET();
        error = do_sys_fstatvfs(l, SCARG(uap, fd), ST_WAIT, sb);
        if (error == 0) {
                bsd_to_linux_statfs(sb, &ltmp);
                error = copyout(&ltmp, SCARG(uap, sp), sizeof ltmp);
        }
        STATVFSBUF_PUT(sb);

        return error;
}

/*
 * uname(). Just copy the info from the various strings stored in the
 * kernel, and put it in the Linux utsname structure. That structure
 * is almost the same as the NetBSD one, only it has fields 65 characters
 * long, and an extra domainname field.
 */
int
linux_sys_uname(struct lwp *l, const struct linux_sys_uname_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct linux_utsname *) up;
        } */
        struct linux_utsname luts;

        memset(&luts, 0, sizeof(luts));
        strlcpy(luts.l_sysname, linux_sysname, sizeof(luts.l_sysname));
        strlcpy(luts.l_nodename, hostname, sizeof(luts.l_nodename));
        strlcpy(luts.l_release, linux_release, sizeof(luts.l_release));
        strlcpy(luts.l_version, linux_version, sizeof(luts.l_version));
        strlcpy(luts.l_machine, LINUX_UNAME_ARCH, sizeof(luts.l_machine));
        strlcpy(luts.l_domainname, domainname, sizeof(luts.l_domainname));

        return copyout(&luts, SCARG(uap, up), sizeof(luts));
}

/* Used directly on: alpha, mips, ppc, sparc, sparc64 */
/* Used indirectly on: arm, i386, m68k */

/*
 * New type Linux mmap call.
 * Only called directly on machines with >= 6 free regs.
 */
int
linux_sys_mmap(struct lwp *l, const struct linux_sys_mmap_args *uap, register_t *retval)
{
        /* {
                syscallarg(unsigned long) addr;
                syscallarg(size_t) len;
                syscallarg(int) prot;
                syscallarg(int) flags;
                syscallarg(int) fd;
                syscallarg(linux_off_t) offset;
        } */

        if (SCARG(uap, offset) & PAGE_MASK)
                return EINVAL;

        return linux_mmap(l, uap, retval, SCARG(uap, offset));
}

/*
 * Guts of most architectures' mmap64() implementations.  This shares
 * its list of arguments with linux_sys_mmap().
 *
 * The difference in linux_sys_mmap2() is that "offset" is actually
 * (offset / pagesize), not an absolute byte count.  This translation
 * to pagesize offsets is done inside glibc between the mmap64() call
 * point, and the actual syscall.
 */
int
linux_sys_mmap2(struct lwp *l, const struct linux_sys_mmap2_args *uap, register_t *retval)
{
        /* {
                syscallarg(unsigned long) addr;
                syscallarg(size_t) len;
                syscallarg(int) prot;
                syscallarg(int) flags;
                syscallarg(int) fd;
                syscallarg(linux_off_t) offset;
        } */

        return linux_mmap(l, uap, retval,
            ((off_t)SCARG(uap, offset)) << PAGE_SHIFT);
}

/*
 * Massage arguments and call system mmap(2).
 */
static int
linux_mmap(struct lwp *l, const struct linux_sys_mmap_args *uap, register_t *retval, off_t offset)
{
        struct sys_mmap_args cma;
        int error;
        size_t mmoff=0;

        linux_to_bsd_mmap_args(&cma, uap);
        SCARG(&cma, pos) = offset;

        if (SCARG(uap, flags) & LINUX_MAP_GROWSDOWN) {
                /*
                 * Request for stack-like memory segment. On linux, this
                 * works by mmap()ping (small) segment, which is automatically
                 * extended when page fault happens below the currently
                 * allocated area. We emulate this by allocating (typically
                 * bigger) segment sized at current stack size limit, and
                 * offsetting the requested and returned address accordingly.
                 * Since physical pages are only allocated on-demand, this
                 * is effectively identical.
                 */
                rlim_t ssl = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur;

                if (SCARG(&cma, len) < ssl) {
                        /* Compute the address offset */
                        mmoff = round_page(ssl) - SCARG(uap, len);

                        if (SCARG(&cma, addr))
                                SCARG(&cma, addr) = (char *)SCARG(&cma, addr) - mmoff;

                        SCARG(&cma, len) = (size_t) ssl;
                }
        }

        error = sys_mmap(l, &cma, retval);
        if (error)
                return (error);

        /* Shift the returned address for stack-like segment if necessary */
        retval[0] += mmoff;

        return (0);
}

static void
linux_to_bsd_mmap_args(struct sys_mmap_args *cma, const struct linux_sys_mmap_args *uap)
{
        int flags = MAP_TRYFIXED, fl = SCARG(uap, flags);

        flags |= cvtto_bsd_mask(fl, LINUX_MAP_SHARED, MAP_SHARED);
        flags |= cvtto_bsd_mask(fl, LINUX_MAP_PRIVATE, MAP_PRIVATE);
        flags |= cvtto_bsd_mask(fl, LINUX_MAP_FIXED, MAP_FIXED);
        flags |= cvtto_bsd_mask(fl, LINUX_MAP_ANON, MAP_ANON);
        flags |= cvtto_bsd_mask(fl, LINUX_MAP_LOCKED, MAP_WIRED);
        /* XXX XAX ERH: Any other flags here?  There are more defined... */

        SCARG(cma, addr) = (void *)SCARG(uap, addr);
        SCARG(cma, len) = SCARG(uap, len);
        SCARG(cma, prot) = SCARG(uap, prot);
        if (SCARG(cma, prot) & VM_PROT_WRITE) /* XXX */
                SCARG(cma, prot) |= VM_PROT_READ;
        SCARG(cma, flags) = flags;
        SCARG(cma, fd) = flags & MAP_ANON ? -1 : SCARG(uap, fd);
        SCARG(cma, PAD) = 0;
}

#define LINUX_MREMAP_MAYMOVE    1
#define LINUX_MREMAP_FIXED      2

int
linux_sys_mremap(struct lwp *l, const struct linux_sys_mremap_args *uap, register_t *retval)
{
        /* {
                syscallarg(void *) old_address;
                syscallarg(size_t) old_size;
                syscallarg(size_t) new_size;
                syscallarg(u_long) flags;
        } */

        struct proc *p;
        struct vm_map *map;
        vaddr_t oldva;
        vaddr_t newva;
        size_t oldsize;
        size_t newsize;
        int flags;
        int uvmflags;
        int error;

        flags = SCARG(uap, flags);
        oldva = (vaddr_t)SCARG(uap, old_address);
        oldsize = round_page(SCARG(uap, old_size));
        newsize = round_page(SCARG(uap, new_size));
        if ((flags & ~(LINUX_MREMAP_FIXED|LINUX_MREMAP_MAYMOVE)) != 0) {
                error = EINVAL;
                goto done;
        }
        if ((flags & LINUX_MREMAP_FIXED) != 0) {
                if ((flags & LINUX_MREMAP_MAYMOVE) == 0) {
                        error = EINVAL;
                        goto done;
                }
#if 0 /* notyet */
                newva = SCARG(uap, new_address);
                uvmflags = MAP_FIXED;
#else /* notyet */
                error = EOPNOTSUPP;
                goto done;
#endif /* notyet */
        } else if ((flags & LINUX_MREMAP_MAYMOVE) != 0) {
                uvmflags = 0;
        } else {
                newva = oldva;
                uvmflags = MAP_FIXED;
        }
        p = l->l_proc;
        map = &p->p_vmspace->vm_map;
        error = uvm_mremap(map, oldva, oldsize, map, &newva, newsize, p,
            uvmflags);

done:
        *retval = (error != 0) ? 0 : (register_t)newva;
        return error;
}

#ifdef USRSTACK
int
linux_sys_mprotect(struct lwp *l, const struct linux_sys_mprotect_args *uap, register_t *retval)
{
        /* {
                syscallarg(const void *) start;
                syscallarg(unsigned long) len;
                syscallarg(int) prot;
        } */
        struct vm_map_entry *entry;
        struct vm_map *map;
        struct proc *p;
        vaddr_t end, start, len, stacklim;
        int prot, grows;

        start = (vaddr_t)SCARG(uap, start);
        len = round_page(SCARG(uap, len));
        prot = SCARG(uap, prot);
        grows = prot & (LINUX_PROT_GROWSDOWN | LINUX_PROT_GROWSUP);
        prot &= ~grows;
        end = start + len;

        if (start & PAGE_MASK)
                return EINVAL;
        if (end < start)
                return EINVAL;
        if (end == start)
                return 0;

        if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
                return EINVAL;
        if (grows == (LINUX_PROT_GROWSDOWN | LINUX_PROT_GROWSUP))
                return EINVAL;

        p = l->l_proc;
        map = &p->p_vmspace->vm_map;
        vm_map_lock(map);
# ifdef notdef
        VM_MAP_RANGE_CHECK(map, start, end);
# endif
        if (!uvm_map_lookup_entry(map, start, &entry) || entry->start > start) {
                vm_map_unlock(map);
                return ENOMEM;
        }

        /*
         * Approximate the behaviour of PROT_GROWS{DOWN,UP}.
         */

        stacklim = (vaddr_t)p->p_limit->pl_rlimit[RLIMIT_STACK].rlim_cur;
        if (grows & LINUX_PROT_GROWSDOWN) {
                if (USRSTACK - stacklim <= start && start < USRSTACK) {
                        start = USRSTACK - stacklim;
                } else {
                        start = entry->start;
                }
        } else if (grows & LINUX_PROT_GROWSUP) {
                if (USRSTACK <= end && end < USRSTACK + stacklim) {
                        end = USRSTACK + stacklim;
                } else {
                        end = entry->end;
                }
        }
        vm_map_unlock(map);
        return uvm_map_protect_user(l, start, end, prot);
}
#endif /* USRSTACK */

/*
 * This code is partly stolen from src/lib/libc/compat-43/times.c
 */

#define CONVTCK(r)      (r.tv_sec * hz + r.tv_usec / (1000000 / hz))

int
linux_sys_times(struct lwp *l, const struct linux_sys_times_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct times *) tms;
        } */
        struct proc *p = l->l_proc;
        struct timeval t;
        int error;

        if (SCARG(uap, tms)) {
                struct linux_tms ltms;
                struct rusage ru;

                memset(&ltms, 0, sizeof(ltms));

                mutex_enter(p->p_lock);
                calcru(p, &ru.ru_utime, &ru.ru_stime, NULL, NULL);
                ltms.ltms_utime = CONVTCK(ru.ru_utime);
                ltms.ltms_stime = CONVTCK(ru.ru_stime);
                ltms.ltms_cutime = CONVTCK(p->p_stats->p_cru.ru_utime);
                ltms.ltms_cstime = CONVTCK(p->p_stats->p_cru.ru_stime);
                mutex_exit(p->p_lock);

                if ((error = copyout(&ltms, SCARG(uap, tms), sizeof ltms)))
                        return error;
        }

        getmicrouptime(&t);

        retval[0] = ((linux_clock_t)(CONVTCK(t)));
        return 0;
}

#undef CONVTCK

#if !defined(__aarch64__)
/*
 * Linux 'readdir' call. This code is mostly taken from the
 * SunOS getdents call (see compat/sunos/sunos_misc.c), though
 * an attempt has been made to keep it a little cleaner (failing
 * miserably, because of the cruft needed if count 1 is passed).
 *
 * The d_off field should contain the offset of the next valid entry,
 * but in Linux it has the offset of the entry itself. We emulate
 * that bug here.
 *
 * Read in BSD-style entries, convert them, and copy them out.
 *
 * Note that this doesn't handle union-mounted filesystems.
 */
int
linux_sys_getdents(struct lwp *l, const struct linux_sys_getdents_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) fd;
                syscallarg(struct linux_dirent *) dent;
                syscallarg(unsigned int) count;
        } */
        struct dirent *bdp;
        struct vnode *vp;
        char *inp, *tbuf;               /* BSD-format */
        int len, reclen;                /* BSD-format */
        char *outp;                     /* Linux-format */
        int resid, linux_reclen = 0;    /* Linux-format */
        struct file *fp;
        struct uio auio;
        struct iovec aiov;
        struct linux_dirent idb;
        off_t off;              /* true file offset */
        int buflen, error, eofflag, nbytes, oldcall;
        struct vattr va;
        off_t *cookiebuf = NULL, *cookie;
        int ncookies;

        /* fd_getvnode() will use the descriptor for us */
        if ((error = fd_getvnode(SCARG(uap, fd), &fp)) != 0)
                return (error);

        if ((fp->f_flag & FREAD) == 0) {
                error = EBADF;
                goto out1;
        }

        vp = (struct vnode *)fp->f_data;
        if (vp->v_type != VDIR) {
                error = ENOTDIR;
                goto out1;
        }

        vn_lock(vp, LK_SHARED | LK_RETRY);
        error = VOP_GETATTR(vp, &va, l->l_cred);
        VOP_UNLOCK(vp);
        if (error)
                goto out1;

        nbytes = SCARG(uap, count);
        if (nbytes == 1) {      /* emulating old, broken behaviour */
                nbytes = sizeof (idb);
                buflen = uimax(va.va_blocksize, nbytes);
                oldcall = 1;
        } else {
                buflen = uimin(MAXBSIZE, nbytes);
                if (buflen < va.va_blocksize)
                        buflen = va.va_blocksize;
                oldcall = 0;
        }
        tbuf = malloc(buflen, M_TEMP, M_WAITOK);

        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        off = fp->f_offset;
again:
        aiov.iov_base = tbuf;
        aiov.iov_len = buflen;
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        auio.uio_rw = UIO_READ;
        auio.uio_resid = buflen;
        auio.uio_offset = off;
        UIO_SETUP_SYSSPACE(&auio);
        /*
         * First we read into the malloc'ed buffer, then
         * we massage it into user space, one record at a time.
         */
        error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, &cookiebuf,
            &ncookies);
        if (error)
                goto out;

        inp = tbuf;
        outp = (void *)SCARG(uap, dent);
        resid = nbytes;
        if ((len = buflen - auio.uio_resid) == 0)
                goto eof;

        for (cookie = cookiebuf; len > 0; len -= reclen) {
                bdp = (struct dirent *)inp;
                reclen = bdp->d_reclen;
                if (reclen & 3) {
                        error = EIO;
                        goto out;
                }
                if (bdp->d_fileno == 0) {
                        inp += reclen;  /* it is a hole; squish it out */
                        if (cookie)
                                off = *cookie++;
                        else
                                off += reclen;
                        continue;
                }
                linux_reclen = LINUX_RECLEN(&idb, bdp->d_namlen);
                if (reclen > len || resid < linux_reclen) {
                        /* entry too big for buffer, so just stop */
                        outp++;
                        break;
                }
                /*
                 * Massage in place to make a Linux-shaped dirent (otherwise
                 * we have to worry about touching user memory outside of
                 * the copyout() call).
                 */
                memset(&idb, 0, sizeof(idb));
                idb.d_ino = bdp->d_fileno;
                /*
                 * The old readdir() call misuses the offset and reclen fields.
                 */
                if (oldcall) {
                        idb.d_off = (linux_off_t)linux_reclen;
                        idb.d_reclen = (u_short)bdp->d_namlen;
                } else {
                        if (sizeof (idb.d_off) <= 4 && (off >> 32) != 0) {
                                compat_offseterr(vp, "linux_getdents");
                                error = EINVAL;
                                goto out;
                        }
                        idb.d_off = (linux_off_t)off;
                        idb.d_reclen = (u_short)linux_reclen;
                        /* Linux puts d_type at the end of each record */
                        *((char *)&idb + idb.d_reclen - 1) = bdp->d_type;
                }
                memcpy(idb.d_name, bdp->d_name,
                    MIN(sizeof(idb.d_name), bdp->d_namlen + 1));
                if ((error = copyout((void *)&idb, outp, linux_reclen)))
                        goto out;
                /* advance past this real entry */
                inp += reclen;
                if (cookie)
                        off = *cookie++; /* each entry points to itself */
                else
                        off += reclen;
                /* advance output past Linux-shaped entry */
                outp += linux_reclen;
                resid -= linux_reclen;
                if (oldcall)
                        break;
        }

        /* if we squished out the whole block, try again */
        if (outp == (void *)SCARG(uap, dent)) {
                if (cookiebuf)
                        free(cookiebuf, M_TEMP);
                cookiebuf = NULL;
                goto again;
        }
        fp->f_offset = off;     /* update the vnode offset */

        if (oldcall)
                nbytes = resid + linux_reclen;

eof:
        *retval = nbytes - resid;
out:
        VOP_UNLOCK(vp);
        if (cookiebuf)
                free(cookiebuf, M_TEMP);
        free(tbuf, M_TEMP);
out1:
        fd_putfile(SCARG(uap, fd));
        return error;
}
#endif

#if !defined(__aarch64__)
/*
 * Even when just using registers to pass arguments to syscalls you can
 * have 5 of them on the i386. So this newer version of select() does
 * this.
 */
int
linux_sys_select(struct lwp *l, const struct linux_sys_select_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) nfds;
                syscallarg(fd_set *) readfds;
                syscallarg(fd_set *) writefds;
                syscallarg(fd_set *) exceptfds;
                syscallarg(struct timeval50 *) timeout;
        } */

        return linux_select1(l, retval, SCARG(uap, nfds), SCARG(uap, readfds),
            SCARG(uap, writefds), SCARG(uap, exceptfds),
            (struct linux_timeval *)SCARG(uap, timeout));
}

/*
 * Common code for the old and new versions of select(). A couple of
 * things are important:
 * 1) return the amount of time left in the 'timeout' parameter
 * 2) select never returns ERESTART on Linux, always return EINTR
 */
int
linux_select1(struct lwp *l, register_t *retval, int nfds, fd_set *readfds,
    fd_set *writefds, fd_set *exceptfds, struct linux_timeval *timeout)
{
        struct timespec ts0, ts1, uts, *ts = NULL;
        struct linux_timeval ltv;
        int error;

        /*
         * Store current time for computation of the amount of
         * time left.
         */
        if (timeout) {
                if ((error = copyin(timeout, &ltv, sizeof(ltv))))
                        return error;
                uts.tv_sec = ltv.tv_sec;
                uts.tv_nsec = (long)((unsigned long)ltv.tv_usec * 1000);
                if (itimespecfix(&uts)) {
                        /*
                         * The timeval was invalid.  Convert it to something
                         * valid that will act as it does under Linux.
                         */
                        uts.tv_sec += uts.tv_nsec / 1000000000;
                        uts.tv_nsec %= 1000000000;
                        if (uts.tv_nsec < 0) {
                                uts.tv_sec -= 1;
                                uts.tv_nsec += 1000000000;
                        }
                        if (uts.tv_sec < 0)
                                timespecclear(&uts);
                }
                ts = &uts;
                nanotime(&ts0);
        }

        error = selcommon(retval, nfds, readfds, writefds, exceptfds, ts, NULL);

        if (error) {
                /*
                 * See fs/select.c in the Linux kernel.  Without this,
                 * Maelstrom doesn't work.
                 */
                if (error == ERESTART)
                        error = EINTR;
                return error;
        }

        if (timeout) {
                if (*retval) {
                        /*
                         * Compute how much time was left of the timeout,
                         * by subtracting the current time and the time
                         * before we started the call, and subtracting
                         * that result from the user-supplied value.
                         */
                        nanotime(&ts1);
                        timespecsub(&ts1, &ts0, &ts1);
                        timespecsub(&uts, &ts1, &uts);
                        if (uts.tv_sec < 0)
                                timespecclear(&uts);
                } else
                        timespecclear(&uts);
                ltv.tv_sec = uts.tv_sec;
                ltv.tv_usec = uts.tv_nsec / 1000;
                if ((error = copyout(&ltv, timeout, sizeof(ltv))))
                        return error;
        }

        return 0;
}
#endif

/*
 * Derived from FreeBSD's sys/compat/linux/linux_misc.c:linux_pselect6()
 * which was contributed by Dmitry Chagin
 * https://svnweb.freebsd.org/base?view=revision&revision=283403
 */
int
linux_sys_pselect6(struct lwp *l,
        const struct linux_sys_pselect6_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) nfds;
                syscallarg(fd_set *) readfds;
                syscallarg(fd_set *) writefds;
                syscallarg(fd_set *) exceptfds;
                syscallarg(struct timespec *) timeout;
                syscallarg(linux_sized_sigset_t *) ss;
        } */
        struct timespec uts, ts0, ts1, *tsp;
        linux_sized_sigset_t lsss;
        struct linux_timespec lts;
        linux_sigset_t lss;
        sigset_t *ssp;
        sigset_t ss;
        int error;

        ssp = NULL;
        if (SCARG(uap, ss) != NULL) {
                if ((error = copyin(SCARG(uap, ss), &lsss, sizeof(lsss))) != 0)
                        return (error);
                if (lsss.ss_len != sizeof(lss))
                        return (EINVAL);
                if (lsss.ss != NULL) {
                        if ((error = copyin(lsss.ss, &lss, sizeof(lss))) != 0)
                                return (error);
                        linux_to_native_sigset(&ss, &lss);
                        ssp = &ss;
                }
        }

        if (SCARG(uap, timeout) != NULL) {
                error = copyin(SCARG(uap, timeout), &lts, sizeof(lts));
                if (error != 0)
                        return (error);
                linux_to_native_timespec(&uts, &lts);

                if (itimespecfix(&uts))
                        return (EINVAL);

                nanotime(&ts0);
                tsp = &uts;
        } else {
                tsp = NULL;
        }

        error = selcommon(retval, SCARG(uap, nfds), SCARG(uap, readfds),
            SCARG(uap, writefds), SCARG(uap, exceptfds), tsp, ssp);

        if (error == 0 && tsp != NULL) {
                if (retval != 0) {
                        /*
                         * Compute how much time was left of the timeout,
                         * by subtracting the current time and the time
                         * before we started the call, and subtracting
                         * that result from the user-supplied value.
                         */
                        nanotime(&ts1);
                        timespecsub(&ts1, &ts0, &ts1);
                        timespecsub(&uts, &ts1, &uts);
                        if (uts.tv_sec < 0)
                                timespecclear(&uts);
                } else {
                        timespecclear(&uts);
                }

                native_to_linux_timespec(&lts, &uts);
                error = copyout(&lts, SCARG(uap, timeout), sizeof(lts));
        }

        return (error);
}

int
linux_sys_ppoll(struct lwp *l,
        const struct linux_sys_ppoll_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct pollfd *) fds;
                syscallarg(u_int) nfds;
                syscallarg(struct linux_timespec *) timeout;
                syscallarg(linux_sigset_t *) sigset;
        } */
        struct linux_timespec lts0, *lts;
        struct timespec ts0, *ts = NULL;
        linux_sigset_t lsigmask0, *lsigmask;
        sigset_t sigmask0, *sigmask = NULL;
        int error;

        lts = SCARG(uap, timeout);
        if (lts) {
                if ((error = copyin(lts, &lts0, sizeof(lts0))) != 0)
                        return error;
                linux_to_native_timespec(&ts0, &lts0);
                ts = &ts0;
        }

        lsigmask = SCARG(uap, sigset);
        if (lsigmask) {
                if ((error = copyin(lsigmask, &lsigmask0, sizeof(lsigmask0))))
                        return error;
                linux_to_native_sigset(&sigmask0, &lsigmask0);
                sigmask = &sigmask0;
        }

        return pollcommon(retval, SCARG(uap, fds), SCARG(uap, nfds),
            ts, sigmask);
}

/*
 * Set the 'personality' (emulation mode) for the current process. Only
 * accept the Linux personality here (0). This call is needed because
 * the Linux ELF crt0 issues it in an ugly kludge to make sure that
 * ELF binaries run in Linux mode, not SVR4 mode.
 */
int
linux_sys_personality(struct lwp *l, const struct linux_sys_personality_args *uap, register_t *retval)
{
        /* {
                syscallarg(unsigned long) per;
        } */
        struct linux_emuldata *led;
        int per;

        per = SCARG(uap, per);
        led = l->l_emuldata;
        if (per == LINUX_PER_QUERY) {
                retval[0] = led->led_personality;
                return 0;
        }

        switch (per & LINUX_PER_MASK) {
        case LINUX_PER_LINUX:
        case LINUX_PER_LINUX32:
                led->led_personality = per;
                break;

        default:
                return EINVAL;
        }

        retval[0] = per;
        return 0;
}

/*
 * We have nonexistent fsuid equal to uid.
 * If modification is requested, refuse.
 */
int
linux_sys_setfsuid(struct lwp *l, const struct linux_sys_setfsuid_args *uap, register_t *retval)
{
         /* {
                 syscallarg(uid_t) uid;
         } */
         uid_t uid;

         uid = SCARG(uap, uid);
         if (kauth_cred_getuid(l->l_cred) != uid)
                 return sys_nosys(l, uap, retval);

         *retval = uid;
         return 0;
}

int
linux_sys_setfsgid(struct lwp *l, const struct linux_sys_setfsgid_args *uap, register_t *retval)
{
        /* {
                syscallarg(gid_t) gid;
        } */
        gid_t gid;

        gid = SCARG(uap, gid);
        if (kauth_cred_getgid(l->l_cred) != gid)
                return sys_nosys(l, uap, retval);

        *retval = gid;
        return 0;
}

int
linux_sys_setresuid(struct lwp *l, const struct linux_sys_setresuid_args *uap, register_t *retval)
{
        /* {
                syscallarg(uid_t) ruid;
                syscallarg(uid_t) euid;
                syscallarg(uid_t) suid;
        } */

        /*
         * Note: These checks are a little different than the NetBSD
         * setreuid(2) call performs.  This precisely follows the
         * behavior of the Linux kernel.
         */

        return do_setresuid(l, SCARG(uap, ruid), SCARG(uap, euid),
                            SCARG(uap, suid),
                            ID_R_EQ_R | ID_R_EQ_E | ID_R_EQ_S |
                            ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
                            ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S );
}

int
linux_sys_getresuid(struct lwp *l, const struct linux_sys_getresuid_args *uap, register_t *retval)
{
        /* {
                syscallarg(uid_t *) ruid;
                syscallarg(uid_t *) euid;
                syscallarg(uid_t *) suid;
        } */
        kauth_cred_t pc = l->l_cred;
        int error;
        uid_t uid;

        /*
         * Linux copies these values out to userspace like so:
         *
         *      1. Copy out ruid.
         *      2. If that succeeds, copy out euid.
         *      3. If both of those succeed, copy out suid.
         */
        uid = kauth_cred_getuid(pc);
        if ((error = copyout(&uid, SCARG(uap, ruid), sizeof(uid_t))) != 0)
                return (error);

        uid = kauth_cred_geteuid(pc);
        if ((error = copyout(&uid, SCARG(uap, euid), sizeof(uid_t))) != 0)
                return (error);

        uid = kauth_cred_getsvuid(pc);

        return (copyout(&uid, SCARG(uap, suid), sizeof(uid_t)));
}

int
linux_sys_ptrace(struct lwp *l, const struct linux_sys_ptrace_args *uap, register_t *retval)
{
        /* {
                i386, m68k, powerpc: T=int
                alpha, amd64: T=long
                syscallarg(T) request;
                syscallarg(T) pid;
                syscallarg(T) addr;
                syscallarg(T) data;
        } */
        const int *ptr;
        int request;
        int error;

        ptr = linux_ptrace_request_map;
        request = SCARG(uap, request);
        while (*ptr != -1)
                if (*ptr++ == request) {
                        struct sys_ptrace_args pta;

                        SCARG(&pta, req) = *ptr;
                        SCARG(&pta, pid) = SCARG(uap, pid);
                        SCARG(&pta, addr) = (void *)SCARG(uap, addr);
                        SCARG(&pta, data) = SCARG(uap, data);

                        /*
                         * Linux ptrace(PTRACE_CONT, pid, 0, 0) means actually
                         * to continue where the process left off previously.
                         * The same thing is achieved by addr == (void *) 1
                         * on NetBSD, so rewrite 'addr' appropriately.
                         */
                        if (request == LINUX_PTRACE_CONT && SCARG(uap, addr)==0)
                                SCARG(&pta, addr) = (void *) 1;

                        error = sysent[SYS_ptrace].sy_call(l, &pta, retval);
                        if (error)
                                return error;
                        switch (request) {
                        case LINUX_PTRACE_PEEKTEXT:
                        case LINUX_PTRACE_PEEKDATA:
                                error = copyout (retval,
                                    (void *)SCARG(uap, data),
                                    sizeof *retval);
                                *retval = SCARG(uap, data);
                                break;
                        default:
                                break;
                        }
                        return error;
                }
                else
                        ptr++;

        return LINUX_SYS_PTRACE_ARCH(l, uap, retval);
}

int
linux_sys_reboot(struct lwp *l, const struct linux_sys_reboot_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) magic1;
                syscallarg(int) magic2;
                syscallarg(int) cmd;
                syscallarg(void *) arg;
        } */
        struct sys_reboot_args /* {
                syscallarg(int) opt;
                syscallarg(char *) bootstr;
        } */ sra;
        int error;

        if ((error = kauth_authorize_system(l->l_cred,
            KAUTH_SYSTEM_REBOOT, 0, NULL, NULL, NULL)) != 0)
                return(error);

        if (SCARG(uap, magic1) != LINUX_REBOOT_MAGIC1)
                return(EINVAL);
        if (SCARG(uap, magic2) != LINUX_REBOOT_MAGIC2 &&
            SCARG(uap, magic2) != LINUX_REBOOT_MAGIC2A &&
            SCARG(uap, magic2) != LINUX_REBOOT_MAGIC2B)
                return(EINVAL);

        switch ((unsigned long)SCARG(uap, cmd)) {
        case LINUX_REBOOT_CMD_RESTART:
                SCARG(&sra, opt) = RB_AUTOBOOT;
                break;
        case LINUX_REBOOT_CMD_HALT:
                SCARG(&sra, opt) = RB_HALT;
                break;
        case LINUX_REBOOT_CMD_POWER_OFF:
                SCARG(&sra, opt) = RB_HALT|RB_POWERDOWN;
                break;
        case LINUX_REBOOT_CMD_RESTART2:
                /* Reboot with an argument. */
                SCARG(&sra, opt) = RB_AUTOBOOT|RB_STRING;
                SCARG(&sra, bootstr) = SCARG(uap, arg);
                break;
        case LINUX_REBOOT_CMD_CAD_ON:
                return(EINVAL); /* We don't implement ctrl-alt-delete */
        case LINUX_REBOOT_CMD_CAD_OFF:
                return(0);
        default:
                return(EINVAL);
        }

        return(sys_reboot(l, &sra, retval));
}

/*
 * Copy of compat_12_sys_swapon().
 */
int
linux_sys_swapon(struct lwp *l, const struct linux_sys_swapon_args *uap, register_t *retval)
{
        /* {
                syscallarg(const char *) name;
        } */
        struct sys_swapctl_args ua;

        SCARG(&ua, cmd) = SWAP_ON;
        SCARG(&ua, arg) = (void *)__UNCONST(SCARG(uap, name));
        SCARG(&ua, misc) = 0;   /* priority */
        return (sys_swapctl(l, &ua, retval));
}

/*
 * Stop swapping to the file or block device specified by path.
 */
int
linux_sys_swapoff(struct lwp *l, const struct linux_sys_swapoff_args *uap, register_t *retval)
{
        /* {
                syscallarg(const char *) path;
        } */
        struct sys_swapctl_args ua;

        SCARG(&ua, cmd) = SWAP_OFF;
        SCARG(&ua, arg) = __UNCONST(SCARG(uap, path)); /*XXXUNCONST*/
        return (sys_swapctl(l, &ua, retval));
}

/*
 * Copy of compat_09_sys_setdomainname()
 */
/* ARGSUSED */
int
linux_sys_setdomainname(struct lwp *l, const struct linux_sys_setdomainname_args *uap, register_t *retval)
{
        /* {
                syscallarg(char *) domainname;
                syscallarg(int) len;
        } */
        int name[2];

        name[0] = CTL_KERN;
        name[1] = KERN_DOMAINNAME;
        return (old_sysctl(&name[0], 2, 0, 0, SCARG(uap, domainname),
                            SCARG(uap, len), l));
}

/*
 * sysinfo()
 */
/* ARGSUSED */
int
linux_sys_sysinfo(struct lwp *l, const struct linux_sys_sysinfo_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct linux_sysinfo *) arg;
        } */
        struct linux_sysinfo si;
        struct loadavg *la;
        int64_t filepg;

        memset(&si, 0, sizeof(si));
        si.uptime = time_uptime;
        la = &averunnable;
        si.loads[0] = la->ldavg[0] * LINUX_SYSINFO_LOADS_SCALE / la->fscale;
        si.loads[1] = la->ldavg[1] * LINUX_SYSINFO_LOADS_SCALE / la->fscale;
        si.loads[2] = la->ldavg[2] * LINUX_SYSINFO_LOADS_SCALE / la->fscale;
        si.totalram = ctob((u_long)physmem);
        /* uvm_availmem() may sync the counters. */
        si.freeram = (u_long)uvm_availmem(true) * uvmexp.pagesize;
        filepg = cpu_count_get(CPU_COUNT_FILECLEAN) +
            cpu_count_get(CPU_COUNT_FILEDIRTY) +
            cpu_count_get(CPU_COUNT_FILEUNKNOWN) -
            cpu_count_get(CPU_COUNT_EXECPAGES);
        si.sharedram = 0;       /* XXX */
        si.bufferram = (u_long)(filepg * uvmexp.pagesize);
        si.totalswap = (u_long)uvmexp.swpages * uvmexp.pagesize;
        si.freeswap =
            (u_long)(uvmexp.swpages - uvmexp.swpginuse) * uvmexp.pagesize;
        si.procs = atomic_load_relaxed(&nprocs);

        /* The following are only present in newer Linux kernels. */
        si.totalbig = 0;
        si.freebig = 0;
        si.mem_unit = 1;

        return (copyout(&si, SCARG(uap, arg), sizeof si));
}

int
linux_sys_getrlimit(struct lwp *l, const struct linux_sys_getrlimit_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) which;
# ifdef LINUX_LARGEFILE64
                syscallarg(struct rlimit *) rlp;
# else
                syscallarg(struct orlimit *) rlp;
# endif
        } */
# ifdef LINUX_LARGEFILE64
        struct rlimit orl;
# else
        struct orlimit orl;
# endif
        int which;

        which = linux_to_bsd_limit(SCARG(uap, which));
        if (which < 0)
                return -which;

        memset(&orl, 0, sizeof(orl));
        bsd_to_linux_rlimit(&orl, &l->l_proc->p_rlimit[which]);

        return copyout(&orl, SCARG(uap, rlp), sizeof(orl));
}

int
linux_sys_setrlimit(struct lwp *l, const struct linux_sys_setrlimit_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) which;
# ifdef LINUX_LARGEFILE64
                syscallarg(struct rlimit *) rlp;
# else
                syscallarg(struct orlimit *) rlp;
# endif
        } */
        struct rlimit rl;
# ifdef LINUX_LARGEFILE64
        struct rlimit orl;
# else
        struct orlimit orl;
# endif
        int error;
        int which;

        if ((error = copyin(SCARG(uap, rlp), &orl, sizeof(orl))) != 0)
                return error;

        which = linux_to_bsd_limit(SCARG(uap, which));
        if (which < 0)
                return -which;

        linux_to_bsd_rlimit(&rl, &orl);
        return dosetrlimit(l, l->l_proc, which, &rl);
}

# if !defined(__aarch64__) && !defined(__mips__) && !defined(__amd64__)
/* XXX: this doesn't look 100% common, at least mips doesn't have it */
int
linux_sys_ugetrlimit(struct lwp *l, const struct linux_sys_ugetrlimit_args *uap, register_t *retval)
{
        return linux_sys_getrlimit(l, (const void *)uap, retval);
}
# endif

int
linux_sys_prlimit64(struct lwp *l, const struct linux_sys_prlimit64_args *uap, register_t *retval)
{
        /* {
                syscallarg(pid_t) pid;
                syscallarg(int) witch;
                syscallarg(struct rlimit *) new_rlp;
                syscallarg(struct rlimit *) old_rlp;
        }; */
        struct rlimit rl, nrl, orl;
        struct rlimit *p;
        int which;
        int error;

        /* XXX: Cannot operate any process other than its own */
        if (SCARG(uap, pid) != 0)
                return EPERM;

        which = linux_to_bsd_limit(SCARG(uap, which));
        if (which < 0)
                return -which;

        p = SCARG(uap, old_rlp);
        if (p != NULL) {
                memset(&orl, 0, sizeof(orl));
                bsd_to_linux_rlimit64(&orl, &l->l_proc->p_rlimit[which]);
                if ((error = copyout(&orl, p, sizeof(orl))) != 0)
                        return error;
        }

        p = SCARG(uap, new_rlp);
        if (p != NULL) {
                if ((error = copyin(p, &nrl, sizeof(nrl))) != 0)
                        return error;

                linux_to_bsd_rlimit(&rl, &nrl);
                return dosetrlimit(l, l->l_proc, which, &rl);
        }

        return 0;
}

/*
 * This gets called for unsupported syscalls. The difference to sys_nosys()
 * is that process does not get SIGSYS, the call just returns with ENOSYS.
 * This is the way Linux does it and glibc depends on this behaviour.
 */
int
linux_sys_nosys(struct lwp *l, const void *v, register_t *retval)
{
        return (ENOSYS);
}

int
linux_sys_getpriority(struct lwp *l, const struct linux_sys_getpriority_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) which;
                syscallarg(int) who;
        } */
        struct sys_getpriority_args bsa;
        int error;

        SCARG(&bsa, which) = SCARG(uap, which);
        SCARG(&bsa, who) = SCARG(uap, who);

        if ((error = sys_getpriority(l, &bsa, retval)))
                return error;

        *retval = NZERO - *retval;

        return 0;
}

int
linux_do_sys_utimensat(struct lwp *l, int fd, const char *path, struct timespec *tsp, int flags, register_t *retval)
{
        int follow, error;

        follow = (flags & LINUX_AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;

        if (path == NULL && fd != AT_FDCWD) {
                file_t *fp;

                /* fd_getvnode() will use the descriptor for us */
                if ((error = fd_getvnode(fd, &fp)) != 0)
                        return error;
                error = do_sys_utimensat(l, AT_FDCWD, fp->f_data, NULL, 0,
                    tsp, UIO_SYSSPACE);
                fd_putfile(fd);
                return error;
        }

        return do_sys_utimensat(l, fd, NULL, path, follow, tsp, UIO_SYSSPACE);
}

int
linux_sys_utimensat(struct lwp *l, const struct linux_sys_utimensat_args *uap,
        register_t *retval)
{
        /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(const struct linux_timespec *) times;
                syscallarg(int) flag;
        } */
        int error;
        struct linux_timespec lts[2];
        struct timespec *tsp = NULL, ts[2];

        if (SCARG(uap, times)) {
                error = copyin(SCARG(uap, times), &lts, sizeof(lts));
                if (error != 0)
                        return error;
                linux_to_native_timespec(&ts[0], &lts[0]);
                linux_to_native_timespec(&ts[1], &lts[1]);
                tsp = ts;
        }

        return linux_do_sys_utimensat(l, SCARG(uap, fd), SCARG(uap, path),
            tsp, SCARG(uap, flag), retval);
}

int
linux_sys_futex(struct lwp *l, const struct linux_sys_futex_args *uap,
        register_t *retval)
{
        /* {
                syscallarg(int *) uaddr;
                syscallarg(int) op;
                syscallarg(int) val;
                syscallarg(const struct linux_timespec *) timeout;
                syscallarg(int *) uaddr2;
                syscallarg(int) val3;
        } */
        struct linux_timespec lts;
        struct timespec ts, *tsp = NULL;
        int val2 = 0;
        int error;

        /*
         * Linux overlays the "timeout" field and the "val2" field.
         * "timeout" is only valid for FUTEX_WAIT and FUTEX_WAIT_BITSET
         * on Linux.
         */
        const int op = (SCARG(uap, op) & FUTEX_CMD_MASK);
        if ((op == FUTEX_WAIT || op == FUTEX_WAIT_BITSET) &&
            SCARG(uap, timeout) != NULL) {
                if ((error = copyin(SCARG(uap, timeout),
                    &lts, sizeof(lts))) != 0) {
                        return error;
                }
                linux_to_native_timespec(&ts, &lts);
                tsp = &ts;
        } else {
                val2 = (int)(uintptr_t)SCARG(uap, timeout);
        }

        return linux_do_futex(SCARG(uap, uaddr), SCARG(uap, op),
            SCARG(uap, val), tsp, SCARG(uap, uaddr2), val2,
            SCARG(uap, val3), retval);
}

int
linux_do_futex(int *uaddr, int op, int val, struct timespec *timeout,
    int *uaddr2, int val2, int val3, register_t *retval)
{
        /*
         * Always clear FUTEX_PRIVATE_FLAG for Linux processes.
         * NetBSD-native futexes exist in different namespace
         * depending on FUTEX_PRIVATE_FLAG.  This appears not
         * to be the case in Linux, and some futex users will
         * mix private and non-private ops on the same futex
         * object.
         */
        return do_futex(uaddr, op & ~FUTEX_PRIVATE_FLAG,
                        val, timeout, uaddr2, val2, val3, retval);
}

#define LINUX_EFD_SEMAPHORE     0x0001
#define LINUX_EFD_CLOEXEC       LINUX_O_CLOEXEC
#define LINUX_EFD_NONBLOCK      LINUX_O_NONBLOCK

static int
linux_do_eventfd2(struct lwp *l, unsigned int initval, int flags,
    register_t *retval)
{
        int nflags = 0;

        if (flags & ~(LINUX_EFD_SEMAPHORE | LINUX_EFD_CLOEXEC |
                      LINUX_EFD_NONBLOCK)) {
                return EINVAL;
        }
        if (flags & LINUX_EFD_SEMAPHORE) {
                nflags |= EFD_SEMAPHORE;
        }
        if (flags & LINUX_EFD_CLOEXEC) {
                nflags |= EFD_CLOEXEC;
        }
        if (flags & LINUX_EFD_NONBLOCK) {
                nflags |= EFD_NONBLOCK;
        }

        return do_eventfd(l, initval, nflags, retval);
}

int
linux_sys_eventfd(struct lwp *l, const struct linux_sys_eventfd_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(unsigned int) initval;
        } */

        return linux_do_eventfd2(l, SCARG(uap, initval), 0, retval);
}

int
linux_sys_eventfd2(struct lwp *l, const struct linux_sys_eventfd2_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(unsigned int) initval;
                syscallarg(int) flags;
        } */

        return linux_do_eventfd2(l, SCARG(uap, initval), SCARG(uap, flags),
                                 retval);
}

#ifndef __aarch64__
/*
 * epoll_create(2).  Check size and call sys_epoll_create1.
 */
int
linux_sys_epoll_create(struct lwp *l,
    const struct linux_sys_epoll_create_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) size;
        } */
        struct sys_epoll_create1_args ca;

        /*
         * SCARG(uap, size) is unused.  Linux just tests it and then
         * forgets it as well.
         */
        if (SCARG(uap, size) <= 0)
                return EINVAL;

        SCARG(&ca, flags) = 0;
        return sys_epoll_create1(l, &ca, retval);
}
#endif /* !__aarch64__ */

/*
 * epoll_create1(2).  Translate the flags and call sys_epoll_create1.
 */
int
linux_sys_epoll_create1(struct lwp *l,
    const struct linux_sys_epoll_create1_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) flags;
        } */
        struct sys_epoll_create1_args ca;

        if ((SCARG(uap, flags) & ~(LINUX_O_CLOEXEC)) != 0)
                return EINVAL;

        SCARG(&ca, flags) = 0;
        if ((SCARG(uap, flags) & LINUX_O_CLOEXEC) != 0)
                SCARG(&ca, flags) |= EPOLL_CLOEXEC;

        return sys_epoll_create1(l, &ca, retval);
}

/*
 * epoll_ctl(2).  Copyin event and translate it if necessary and then
 * call epoll_ctl_common().
 */
int
linux_sys_epoll_ctl(struct lwp *l, const struct linux_sys_epoll_ctl_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(int) epfd;
                syscallarg(int) op;
                syscallarg(int) fd;
                syscallarg(struct linux_epoll_event *) event;
        } */
        struct linux_epoll_event lee;
        struct epoll_event ee;
        struct epoll_event *eep;
        int error;

        if (SCARG(uap, op) != EPOLL_CTL_DEL) {
                error = copyin(SCARG(uap, event), &lee, sizeof(lee));
                if (error != 0)
                        return error;

                /*
                 * On some architectures, struct linux_epoll_event and
                 * struct epoll_event are packed differently... but otherwise
                 * the contents are the same.
                 */
                ee.events = lee.events;
                ee.data = lee.data;

                eep = &ee;
        } else
                eep = NULL;

        return epoll_ctl_common(l, retval, SCARG(uap, epfd), SCARG(uap, op),
            SCARG(uap, fd), eep);
}

#ifndef __aarch64__
/*
 * epoll_wait(2).  Call sys_epoll_pwait().
 */
int
linux_sys_epoll_wait(struct lwp *l,
    const struct linux_sys_epoll_wait_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) epfd;
                syscallarg(struct linux_epoll_event *) events;
                syscallarg(int) maxevents;
                syscallarg(int) timeout;
        } */
        struct linux_sys_epoll_pwait_args ea;

        SCARG(&ea, epfd) = SCARG(uap, epfd);
        SCARG(&ea, events) = SCARG(uap, events);
        SCARG(&ea, maxevents) = SCARG(uap, maxevents);
        SCARG(&ea, timeout) = SCARG(uap, timeout);
        SCARG(&ea, sigmask) = NULL;

        return linux_sys_epoll_pwait(l, &ea, retval);
}
#endif /* !__aarch64__ */

/*
 * Main body of epoll_pwait2(2).  Translate timeout and sigmask and
 * call epoll_wait_common.
 */
static int
linux_epoll_pwait2_common(struct lwp *l, register_t *retval, int epfd,
    struct linux_epoll_event *events, int maxevents,
    struct linux_timespec *timeout, const linux_sigset_t *sigmask)
{
        struct timespec ts, *tsp;
        linux_sigset_t lss;
        sigset_t ss, *ssp;
        struct epoll_event *eep;
        struct linux_epoll_event *leep;
        int i, error;

        if (maxevents <= 0 || maxevents > EPOLL_MAX_EVENTS)
                return EINVAL;

        if (timeout != NULL) {
                linux_to_native_timespec(&ts, timeout);
                tsp = &ts;
        } else
                tsp = NULL;

        if (sigmask != NULL) {
                error = copyin(sigmask, &lss, sizeof(lss));
                if (error != 0)
                        return error;

                linux_to_native_sigset(&ss, &lss);
                ssp = &ss;
        } else
                ssp = NULL;

        eep = kmem_alloc(maxevents * sizeof(*eep), KM_SLEEP);

        error = epoll_wait_common(l, retval, epfd, eep, maxevents, tsp,
            ssp);
        if (error == 0 && *retval > 0) {
                leep = kmem_alloc((*retval) * sizeof(*leep), KM_SLEEP);

                /* Translate the events (because of packing). */
                for (i = 0; i < *retval; i++) {
                        leep[i].events = eep[i].events;
                        leep[i].data = eep[i].data;
                }

                error = copyout(leep, events, (*retval) * sizeof(*leep));
                kmem_free(leep, (*retval) * sizeof(*leep));
        }

        kmem_free(eep, maxevents * sizeof(*eep));
        return error;
}

/*
 * epoll_pwait(2).  Translate timeout and call sys_epoll_pwait2.
 */
int
linux_sys_epoll_pwait(struct lwp *l,
    const struct linux_sys_epoll_pwait_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) epfd;
                syscallarg(struct linux_epoll_event *) events;
                syscallarg(int) maxevents;
                syscallarg(int) timeout;
                syscallarg(linux_sigset_t *) sigmask;
        } */
        struct linux_timespec lts, *ltsp;
        const int timeout = SCARG(uap, timeout);

        if (timeout >= 0) {
                /* Convert from milliseconds to timespec. */
                lts.tv_sec = timeout / 1000;
                lts.tv_nsec = (timeout % 1000) * 1000000;

                ltsp = &lts;
        } else
                ltsp = NULL;

        return linux_epoll_pwait2_common(l, retval, SCARG(uap, epfd),
            SCARG(uap, events), SCARG(uap, maxevents), ltsp,
            SCARG(uap, sigmask));
}


/*
 * epoll_pwait2(2).  Copyin timeout and call linux_epoll_pwait2_common().
 */
int
linux_sys_epoll_pwait2(struct lwp *l,
    const struct linux_sys_epoll_pwait2_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) epfd;
                syscallarg(struct linux_epoll_event *) events;
                syscallarg(int) maxevents;
                syscallarg(struct linux_timespec *) timeout;
                syscallarg(linux_sigset_t *) sigmask;
        } */
        struct linux_timespec lts, *ltsp;
        int error;

        if (SCARG(uap, timeout) != NULL) {
                error = copyin(SCARG(uap, timeout), &lts, sizeof(lts));
                if (error != 0)
                        return error;

                ltsp = &lts;
        } else
                ltsp = NULL;

        return linux_epoll_pwait2_common(l, retval, SCARG(uap, epfd),
            SCARG(uap, events), SCARG(uap, maxevents), ltsp,
            SCARG(uap, sigmask));
}

#define LINUX_MFD_CLOEXEC       0x0001U
#define LINUX_MFD_ALLOW_SEALING 0x0002U
#define LINUX_MFD_HUGETLB       0x0004U
#define LINUX_MFD_NOEXEC_SEAL   0x0008U
#define LINUX_MFD_EXEC          0x0010U
#define LINUX_MFD_HUGE_FLAGS    (0x3f << 26)

#define LINUX_MFD_ALL_FLAGS     (LINUX_MFD_CLOEXEC|LINUX_MFD_ALLOW_SEALING \
                                |LINUX_MFD_HUGETLB|LINUX_MFD_NOEXEC_SEAL \
                                |LINUX_MFD_EXEC|LINUX_MFD_HUGE_FLAGS)
#define LINUX_MFD_KNOWN_FLAGS   (LINUX_MFD_CLOEXEC|LINUX_MFD_ALLOW_SEALING)

#define LINUX_MFD_NAME_MAX      249

/*
 * memfd_create(2).  Do some error checking and then call NetBSD's
 * version.
 */
int
linux_sys_memfd_create(struct lwp *l,
    const struct linux_sys_memfd_create_args *uap, register_t *retval)
{
        /* {
                syscallarg(const char *) name;
                syscallarg(unsigned int) flags;
        } */
        int error;
        char *pbuf;
        struct sys_memfd_create_args muap;
        const unsigned int lflags = SCARG(uap, flags);

        KASSERT(LINUX_MFD_NAME_MAX < NAME_MAX); /* sanity check */

        if (lflags & ~LINUX_MFD_ALL_FLAGS)
                return EINVAL;
        if ((lflags & LINUX_MFD_HUGE_FLAGS) != 0 &&
            (lflags & LINUX_MFD_HUGETLB) == 0)
                return EINVAL;
        if ((lflags & LINUX_MFD_HUGETLB) && (lflags & LINUX_MFD_ALLOW_SEALING))
                return EINVAL;

        /* Linux has a stricter limit for name size */
        pbuf = PNBUF_GET();
        error = copyinstr(SCARG(uap, name), pbuf, LINUX_MFD_NAME_MAX+1, NULL);
        PNBUF_PUT(pbuf);
        pbuf = NULL;
        if (error != 0) {
                if (error == ENAMETOOLONG)
                        error = EINVAL;
                return error;
        }

        if (lflags & ~LINUX_MFD_KNOWN_FLAGS) {
                DPRINTF("%s: ignored flags %#x\n", __func__,
                    lflags & ~LINUX_MFD_KNOWN_FLAGS);
        }

        SCARG(&muap, name) = SCARG(uap, name);
        SCARG(&muap, flags) = lflags & LINUX_MFD_KNOWN_FLAGS;

        return sys_memfd_create(l, &muap, retval);
}

#define LINUX_CLOSE_RANGE_UNSHARE       0x02U
#define LINUX_CLOSE_RANGE_CLOEXEC       0x04U

/*
 * close_range(2).
 */
int
linux_sys_close_range(struct lwp *l,
    const struct linux_sys_close_range_args *uap, register_t *retval)
{
        /* {
                syscallarg(unsigned int) first;
                syscallarg(unsigned int) last;
                syscallarg(unsigned int) flags;
        } */
        unsigned int fd, last;
        file_t *fp;
        filedesc_t *fdp;
        const unsigned int flags = SCARG(uap, flags);

        if (flags & ~(LINUX_CLOSE_RANGE_CLOEXEC|LINUX_CLOSE_RANGE_UNSHARE))
                return EINVAL;
        if (SCARG(uap, first) > SCARG(uap, last))
                return EINVAL;

        if (flags & LINUX_CLOSE_RANGE_UNSHARE) {
                fdp = fd_copy();
                fd_free();
                l->l_proc->p_fd = fdp;
                l->l_fd = fdp;
        }

        last = MIN(SCARG(uap, last), l->l_proc->p_fd->fd_lastfile);
        for (fd = SCARG(uap, first); fd <= last; fd++) {
                fp = fd_getfile(fd);
                if (fp == NULL)
                        continue;

                if (flags & LINUX_CLOSE_RANGE_CLOEXEC) {
                        fd_set_exclose(l, fd, true);
                        fd_putfile(fd);
                } else
                        fd_close(fd);
        }

        return 0;
}

/*
 * readahead(2).  Call posix_fadvise with POSIX_FADV_WILLNEED with some extra
 * error checking.
 */
int
linux_sys_readahead(struct lwp *l, const struct linux_sys_readahead_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(int) fd;
                syscallarg(off_t) offset;
                syscallarg(size_t) count;
        } */
        file_t *fp;
        int error = 0;
        const int fd = SCARG(uap, fd);

        fp = fd_getfile(fd);
        if (fp == NULL)
                return EBADF;
        if ((fp->f_flag & FREAD) == 0)
                error = EBADF;
        else if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG)
                error = EINVAL;
        fd_putfile(fd);
        if (error != 0)
                return error;

        return do_posix_fadvise(fd, SCARG(uap, offset), SCARG(uap, count),
            POSIX_FADV_WILLNEED);
}

int
linux_sys_getcpu(lwp_t *l, const struct linux_sys_getcpu_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(unsigned int *) cpu;
                syscallarg(unsigned int *) node;
                syscallarg(struct linux_getcpu_cache *) tcache;
        }*/
        int error;

        if (SCARG(uap, cpu)) {
                u_int cpu_id = l->l_cpu->ci_data.cpu_index;
                error = copyout(&cpu_id, SCARG(uap, cpu), sizeof(cpu_id));
                if (error)
                        return error;

        }

        // TO-DO: Test on a NUMA machine if the node_id returned is correct
        if (SCARG(uap, node)) {
                u_int node_id = l->l_cpu->ci_data.cpu_numa_id;
                error = copyout(&node_id, SCARG(uap, node), sizeof(node_id));
                if (error)
                        return error;
        }

        return 0;
}