/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000 Marcel Moolenaar
 * All rights reserved.
 *
 * 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 AUTHOR 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 AUTHOR 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.
 */

#include "opt_posix.h"

#include <sys/param.h>
#include <sys/imgact_aout.h>
#include <sys/fcntl.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/racct.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/vnode.h>

#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>

#include <machine/frame.h>
#include <machine/pcb.h>                        /* needed for pcb definition in linux_set_thread_area */
#include <machine/psl.h>
#include <machine/segments.h>
#include <machine/sysarch.h>

#include <vm/pmap.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_param.h>

#include <x86/reg.h>

#include <i386/linux/linux.h>
#include <i386/linux/linux_proto.h>
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_fork.h>
#include <compat/linux/linux_ipc.h>
#include <compat/linux/linux_misc.h>
#include <compat/linux/linux_mmap.h>
#include <compat/linux/linux_signal.h>
#include <compat/linux/linux_util.h>


struct l_descriptor {
        l_uint          entry_number;
        l_ulong         base_addr;
        l_uint          limit;
        l_uint          seg_32bit:1;
        l_uint          contents:2;
        l_uint          read_exec_only:1;
        l_uint          limit_in_pages:1;
        l_uint          seg_not_present:1;
        l_uint          useable:1;
};

struct l_old_select_argv {
        l_int           nfds;
        l_fd_set        *readfds;
        l_fd_set        *writefds;
        l_fd_set        *exceptfds;
        struct l_timeval        *timeout;
};

struct l_ipc_kludge {
        struct l_msgbuf *msgp;
        l_long msgtyp;
};

int
linux_ipc(struct thread *td, struct linux_ipc_args *args)
{

        switch (args->what & 0xFFFF) {
        case LINUX_SEMOP: {

                return (kern_semop(td, args->arg1, PTRIN(args->ptr),
                    args->arg2, NULL));
        }
        case LINUX_SEMGET: {
                struct linux_semget_args a;

                a.key = args->arg1;
                a.nsems = args->arg2;
                a.semflg = args->arg3;
                return (linux_semget(td, &a));
        }
        case LINUX_SEMCTL: {
                struct linux_semctl_args a;
                int error;

                a.semid = args->arg1;
                a.semnum = args->arg2;
                a.cmd = args->arg3;
                error = copyin(PTRIN(args->ptr), &a.arg, sizeof(a.arg));
                if (error)
                        return (error);
                return (linux_semctl(td, &a));
        }
        case LINUX_SEMTIMEDOP: {
                struct linux_semtimedop_args a;

                a.semid = args->arg1;
                a.tsops = PTRIN(args->ptr);
                a.nsops = args->arg2;
                a.timeout = PTRIN(args->arg5);
                return (linux_semtimedop(td, &a));
        }
        case LINUX_MSGSND: {
                struct linux_msgsnd_args a;

                a.msqid = args->arg1;
                a.msgp = PTRIN(args->ptr);
                a.msgsz = args->arg2;
                a.msgflg = args->arg3;
                return (linux_msgsnd(td, &a));
        }
        case LINUX_MSGRCV: {
                struct linux_msgrcv_args a;

                a.msqid = args->arg1;
                a.msgsz = args->arg2;
                a.msgflg = args->arg3;
                if ((args->what >> 16) == 0) {
                        struct l_ipc_kludge tmp;
                        int error;

                        if (args->ptr == 0)
                                return (EINVAL);
                        error = copyin(PTRIN(args->ptr), &tmp, sizeof(tmp));
                        if (error)
                                return (error);
                        a.msgp = PTRIN(tmp.msgp);
                        a.msgtyp = tmp.msgtyp;
                } else {
                        a.msgp = PTRIN(args->ptr);
                        a.msgtyp = args->arg5;
                }
                return (linux_msgrcv(td, &a));
        }
        case LINUX_MSGGET: {
                struct linux_msgget_args a;

                a.key = args->arg1;
                a.msgflg = args->arg2;
                return (linux_msgget(td, &a));
        }
        case LINUX_MSGCTL: {
                struct linux_msgctl_args a;

                a.msqid = args->arg1;
                a.cmd = args->arg2;
                a.buf = PTRIN(args->ptr);
                return (linux_msgctl(td, &a));
        }
        case LINUX_SHMAT: {
                struct linux_shmat_args a;
                l_uintptr_t addr;
                int error;

                a.shmid = args->arg1;
                a.shmaddr = PTRIN(args->ptr);
                a.shmflg = args->arg2;
                error = linux_shmat(td, &a);
                if (error != 0)
                        return (error);
                addr = td->td_retval[0];
                error = copyout(&addr, PTRIN(args->arg3), sizeof(addr));
                td->td_retval[0] = 0;
                return (error);
        }
        case LINUX_SHMDT: {
                struct linux_shmdt_args a;

                a.shmaddr = PTRIN(args->ptr);
                return (linux_shmdt(td, &a));
        }
        case LINUX_SHMGET: {
                struct linux_shmget_args a;

                a.key = args->arg1;
                a.size = args->arg2;
                a.shmflg = args->arg3;
                return (linux_shmget(td, &a));
        }
        case LINUX_SHMCTL: {
                struct linux_shmctl_args a;

                a.shmid = args->arg1;
                a.cmd = args->arg2;
                a.buf = PTRIN(args->ptr);
                return (linux_shmctl(td, &a));
        }
        default:
                break;
        }

        return (EINVAL);
}

int
linux_old_select(struct thread *td, struct linux_old_select_args *args)
{
        struct l_old_select_argv linux_args;
        struct linux_select_args newsel;
        int error;

        error = copyin(args->ptr, &linux_args, sizeof(linux_args));
        if (error)
                return (error);

        newsel.nfds = linux_args.nfds;
        newsel.readfds = linux_args.readfds;
        newsel.writefds = linux_args.writefds;
        newsel.exceptfds = linux_args.exceptfds;
        newsel.timeout = linux_args.timeout;
        return (linux_select(td, &newsel));
}

int
linux_set_cloned_tls(struct thread *td, void *desc)
{
        struct segment_descriptor sd;
        struct l_user_desc info;
        int idx, error;
        int a[2];

        error = copyin(desc, &info, sizeof(struct l_user_desc));
        if (error) {
                linux_msg(td, "set_cloned_tls copyin failed!");
        } else {
                idx = info.entry_number;

                /*
                 * looks like we're getting the idx we returned
                 * in the set_thread_area() syscall
                 */
                if (idx != 6 && idx != 3) {
                        linux_msg(td, "set_cloned_tls resetting idx!");
                        idx = 3;
                }

                /* this doesnt happen in practice */
                if (idx == 6) {
                        /* we might copy out the entry_number as 3 */
                        info.entry_number = 3;
                        error = copyout(&info, desc, sizeof(struct l_user_desc));
                        if (error)
                                linux_msg(td, "set_cloned_tls copyout failed!");
                }

                a[0] = LINUX_LDT_entry_a(&info);
                a[1] = LINUX_LDT_entry_b(&info);

                memcpy(&sd, &a, sizeof(a));
                /* set %gs */
                td->td_pcb->pcb_gsd = sd;
                td->td_pcb->pcb_gs = GSEL(GUGS_SEL, SEL_UPL);
        }

        return (error);
}

int
linux_set_upcall(struct thread *td, register_t stack)
{

        if (stack)
                td->td_frame->tf_esp = stack;

        /*
         * The newly created Linux thread returns
         * to the user space by the same path that a parent do.
         */
        td->td_frame->tf_eax = 0;
        return (0);
}

int
linux_mmap(struct thread *td, struct linux_mmap_args *args)
{
        int error;
        struct l_mmap_argv linux_args;

        error = copyin(args->ptr, &linux_args, sizeof(linux_args));
        if (error)
                return (error);

        return (linux_mmap_common(td, linux_args.addr, linux_args.len,
            linux_args.prot, linux_args.flags, linux_args.fd,
            (uint32_t)linux_args.pgoff));
}

int
linux_ioperm(struct thread *td, struct linux_ioperm_args *args)
{
        int error;
        struct i386_ioperm_args iia;

        iia.start = args->start;
        iia.length = args->length;
        iia.enable = args->enable;
        error = i386_set_ioperm(td, &iia);
        return (error);
}

int
linux_iopl(struct thread *td, struct linux_iopl_args *args)
{
        int error;

        if (args->level < 0 || args->level > 3)
                return (EINVAL);
        if ((error = priv_check(td, PRIV_IO)) != 0)
                return (error);
        if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
                return (error);
        td->td_frame->tf_eflags = (td->td_frame->tf_eflags & ~PSL_IOPL) |
            (args->level * (PSL_IOPL / 3));
        return (0);
}

int
linux_modify_ldt(struct thread *td, struct linux_modify_ldt_args *uap)
{
        int error;
        struct i386_ldt_args ldt;
        struct l_descriptor ld;
        union descriptor desc;
        int size, written;

        switch (uap->func) {
        case 0x00: /* read_ldt */
                ldt.start = 0;
                ldt.descs = uap->ptr;
                ldt.num = uap->bytecount / sizeof(union descriptor);
                error = i386_get_ldt(td, &ldt);
                td->td_retval[0] *= sizeof(union descriptor);
                break;
        case 0x02: /* read_default_ldt = 0 */
                size = 5*sizeof(struct l_desc_struct);
                if (size > uap->bytecount)
                        size = uap->bytecount;
                for (written = error = 0; written < size && error == 0; written++)
                        error = subyte((char *)uap->ptr + written, 0);
                td->td_retval[0] = written;
                break;
        case 0x01: /* write_ldt */
        case 0x11: /* write_ldt */
                if (uap->bytecount != sizeof(ld))
                        return (EINVAL);

                error = copyin(uap->ptr, &ld, sizeof(ld));
                if (error)
                        return (error);

                ldt.start = ld.entry_number;
                ldt.descs = &desc;
                ldt.num = 1;
                desc.sd.sd_lolimit = (ld.limit & 0x0000ffff);
                desc.sd.sd_hilimit = (ld.limit & 0x000f0000) >> 16;
                desc.sd.sd_lobase = (ld.base_addr & 0x00ffffff);
                desc.sd.sd_hibase = (ld.base_addr & 0xff000000) >> 24;
                desc.sd.sd_type = SDT_MEMRO | ((ld.read_exec_only ^ 1) << 1) |
                        (ld.contents << 2);
                desc.sd.sd_dpl = 3;
                desc.sd.sd_p = (ld.seg_not_present ^ 1);
                desc.sd.sd_xx = 0;
                desc.sd.sd_def32 = ld.seg_32bit;
                desc.sd.sd_gran = ld.limit_in_pages;
                error = i386_set_ldt(td, &ldt, &desc);
                break;
        default:
                error = ENOSYS;
                break;
        }

        if (error == EOPNOTSUPP) {
                linux_msg(td, "modify_ldt needs kernel option USER_LDT");
                error = ENOSYS;
        }

        return (error);
}

int
linux_sigaction(struct thread *td, struct linux_sigaction_args *args)
{
        l_osigaction_t osa;
        l_sigaction_t act, oact;
        int error;

        if (args->nsa != NULL) {
                error = copyin(args->nsa, &osa, sizeof(l_osigaction_t));
                if (error)
                        return (error);
                act.lsa_handler = osa.lsa_handler;
                act.lsa_flags = osa.lsa_flags;
                act.lsa_restorer = osa.lsa_restorer;
                LINUX_SIGEMPTYSET(act.lsa_mask);
                act.lsa_mask.__mask = osa.lsa_mask;
        }

        error = linux_do_sigaction(td, args->sig, args->nsa ? &act : NULL,
            args->osa ? &oact : NULL);

        if (args->osa != NULL && !error) {
                osa.lsa_handler = oact.lsa_handler;
                osa.lsa_flags = oact.lsa_flags;
                osa.lsa_restorer = oact.lsa_restorer;
                osa.lsa_mask = oact.lsa_mask.__mask;
                error = copyout(&osa, args->osa, sizeof(l_osigaction_t));
        }

        return (error);
}

/*
 * Linux has two extra args, restart and oldmask.  We dont use these,
 * but it seems that "restart" is actually a context pointer that
 * enables the signal to happen with a different register set.
 */
int
linux_sigsuspend(struct thread *td, struct linux_sigsuspend_args *args)
{
        sigset_t sigmask;
        l_sigset_t mask;

        LINUX_SIGEMPTYSET(mask);
        mask.__mask = args->mask;
        linux_to_bsd_sigset(&mask, &sigmask);
        return (kern_sigsuspend(td, sigmask));
}

int
linux_pause(struct thread *td, struct linux_pause_args *args)
{
        struct proc *p = td->td_proc;
        sigset_t sigmask;

        PROC_LOCK(p);
        sigmask = td->td_sigmask;
        PROC_UNLOCK(p);
        return (kern_sigsuspend(td, sigmask));
}

int
linux_set_thread_area(struct thread *td, struct linux_set_thread_area_args *args)
{
        struct l_user_desc info;
        int error;
        int idx;
        int a[2];
        struct segment_descriptor sd;

        error = copyin(args->desc, &info, sizeof(struct l_user_desc));
        if (error)
                return (error);

        idx = info.entry_number;
        /*
         * Semantics of Linux version: every thread in the system has array of
         * 3 tls descriptors. 1st is GLIBC TLS, 2nd is WINE, 3rd unknown. This
         * syscall loads one of the selected tls descriptors with a value and
         * also loads GDT descriptors 6, 7 and 8 with the content of the
         * per-thread descriptors.
         *
         * Semantics of FreeBSD version: I think we can ignore that Linux has 3
         * per-thread descriptors and use just the 1st one. The tls_array[]
         * is used only in set/get-thread_area() syscalls and for loading the
         * GDT descriptors. In FreeBSD we use just one GDT descriptor for TLS
         * so we will load just one.
         *
         * XXX: this doesn't work when a user space process tries to use more
         * than 1 TLS segment. Comment in the Linux sources says wine might do
         * this.
         */

        /*
         * we support just GLIBC TLS now
         * we should let 3 proceed as well because we use this segment so
         * if code does two subsequent calls it should succeed
         */
        if (idx != 6 && idx != -1 && idx != 3)
                return (EINVAL);

        /*
         * we have to copy out the GDT entry we use
         * FreeBSD uses GDT entry #3 for storing %gs so load that
         *
         * XXX: what if a user space program doesn't check this value and tries
         * to use 6, 7 or 8?
         */
        idx = info.entry_number = 3;
        error = copyout(&info, args->desc, sizeof(struct l_user_desc));
        if (error)
                return (error);

        if (LINUX_LDT_empty(&info)) {
                a[0] = 0;
                a[1] = 0;
        } else {
                a[0] = LINUX_LDT_entry_a(&info);
                a[1] = LINUX_LDT_entry_b(&info);
        }

        memcpy(&sd, &a, sizeof(a));
        /* this is taken from i386 version of cpu_set_user_tls() */
        critical_enter();
        /* set %gs */
        td->td_pcb->pcb_gsd = sd;
        PCPU_GET(fsgs_gdt)[1] = sd;
        load_gs(GSEL(GUGS_SEL, SEL_UPL));
        critical_exit();

        return (0);
}

int
linux_get_thread_area(struct thread *td, struct linux_get_thread_area_args *args)
{

        struct l_user_desc info;
        int error;
        int idx;
        struct l_desc_struct desc;
        struct segment_descriptor sd;

        error = copyin(args->desc, &info, sizeof(struct l_user_desc));
        if (error)
                return (error);

        idx = info.entry_number;
        /* XXX: I am not sure if we want 3 to be allowed too. */
        if (idx != 6 && idx != 3)
                return (EINVAL);

        idx = 3;

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

        sd = PCPU_GET(fsgs_gdt)[1];

        memcpy(&desc, &sd, sizeof(desc));

        info.entry_number = idx;
        info.base_addr = LINUX_GET_BASE(&desc);
        info.limit = LINUX_GET_LIMIT(&desc);
        info.seg_32bit = LINUX_GET_32BIT(&desc);
        info.contents = LINUX_GET_CONTENTS(&desc);
        info.read_exec_only = !LINUX_GET_WRITABLE(&desc);
        info.limit_in_pages = LINUX_GET_LIMIT_PAGES(&desc);
        info.seg_not_present = !LINUX_GET_PRESENT(&desc);
        info.useable = LINUX_GET_USEABLE(&desc);

        error = copyout(&info, args->desc, sizeof(struct l_user_desc));
        if (error)
                return (EFAULT);

        return (0);
}

void
bsd_to_linux_regset(const struct reg *b_reg,
    struct linux_pt_regset *l_regset)
{

        l_regset->ebx = b_reg->r_ebx;
        l_regset->ecx = b_reg->r_ecx;
        l_regset->edx = b_reg->r_edx;
        l_regset->esi = b_reg->r_esi;
        l_regset->edi = b_reg->r_edi;
        l_regset->ebp = b_reg->r_ebp;
        l_regset->eax = b_reg->r_eax;
        l_regset->ds = b_reg->r_ds;
        l_regset->es = b_reg->r_es;
        l_regset->fs = b_reg->r_fs;
        l_regset->gs = b_reg->r_gs;
        l_regset->orig_eax = b_reg->r_eax;
        l_regset->eip = b_reg->r_eip;
        l_regset->cs = b_reg->r_cs;
        l_regset->eflags = b_reg->r_eflags;
        l_regset->esp = b_reg->r_esp;
        l_regset->ss = b_reg->r_ss;
}

int
linux_uselib(struct thread *td, struct linux_uselib_args *args)
{
        struct nameidata ni;
        struct vnode *vp;
        struct exec *a_out;
        vm_map_t map;
        vm_map_entry_t entry;
        struct vattr attr;
        vm_offset_t vmaddr;
        unsigned long file_offset;
        unsigned long bss_size;
        ssize_t aresid;
        int error;
        bool locked, opened, textset;

        a_out = NULL;
        vp = NULL;
        locked = false;
        textset = false;
        opened = false;

        NDINIT(&ni, LOOKUP, ISOPEN | FOLLOW | LOCKLEAF | AUDITVNODE1,
            UIO_USERSPACE, args->library);
        error = namei(&ni);
        if (error)
                goto cleanup;

        vp = ni.ni_vp;
        NDFREE_PNBUF(&ni);

        /*
         * From here on down, we have a locked vnode that must be unlocked.
         * XXX: The code below largely duplicates exec_check_permissions().
         */
        locked = true;

        /* Executable? */
        error = VOP_GETATTR(vp, &attr, td->td_ucred);
        if (error)
                goto cleanup;

        if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
            ((attr.va_mode & 0111) == 0) || (attr.va_type != VREG)) {
                /* EACCESS is what exec(2) returns. */
                error = ENOEXEC;
                goto cleanup;
        }

        /* Sensible size? */
        if (attr.va_size == 0) {
                error = ENOEXEC;
                goto cleanup;
        }

        /* Can we access it? */
        error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
        if (error)
                goto cleanup;

        /*
         * XXX: This should use vn_open() so that it is properly authorized,
         * and to reduce code redundancy all over the place here.
         * XXX: Not really, it duplicates far more of exec_check_permissions()
         * than vn_open().
         */
#ifdef MAC
        error = mac_vnode_check_open(td->td_ucred, vp, VREAD);
        if (error)
                goto cleanup;
#endif
        error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
        if (error)
                goto cleanup;
        opened = true;

        /* Pull in executable header into exec_map */
        error = vm_mmap(exec_map, (vm_offset_t *)&a_out, PAGE_SIZE,
            VM_PROT_READ, VM_PROT_READ, 0, OBJT_VNODE, vp, 0);
        if (error)
                goto cleanup;

        /* Is it a Linux binary ? */
        if (((a_out->a_magic >> 16) & 0xff) != 0x64) {
                error = ENOEXEC;
                goto cleanup;
        }

        /*
         * While we are here, we should REALLY do some more checks
         */

        /* Set file/virtual offset based on a.out variant. */
        switch ((int)(a_out->a_magic & 0xffff)) {
        case 0413:                      /* ZMAGIC */
                file_offset = 1024;
                break;
        case 0314:                      /* QMAGIC */
                file_offset = 0;
                break;
        default:
                error = ENOEXEC;
                goto cleanup;
        }

        bss_size = round_page(a_out->a_bss);

        /* Check various fields in header for validity/bounds. */
        if (a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK) {
                error = ENOEXEC;
                goto cleanup;
        }

        /* text + data can't exceed file size */
        if (a_out->a_data + a_out->a_text > attr.va_size) {
                error = EFAULT;
                goto cleanup;
        }

        /*
         * text/data/bss must not exceed limits
         * XXX - this is not complete. it should check current usage PLUS
         * the resources needed by this library.
         */
        PROC_LOCK(td->td_proc);
        if (a_out->a_text > maxtsiz ||
            a_out->a_data + bss_size > lim_cur_proc(td->td_proc, RLIMIT_DATA) ||
            racct_set(td->td_proc, RACCT_DATA, a_out->a_data +
            bss_size) != 0) {
                PROC_UNLOCK(td->td_proc);
                error = ENOMEM;
                goto cleanup;
        }
        PROC_UNLOCK(td->td_proc);

        /*
         * Prevent more writers.
         */
        error = VOP_SET_TEXT(vp);
        if (error != 0)
                goto cleanup;
        textset = true;

        /*
         * Lock no longer needed
         */
        locked = false;
        VOP_UNLOCK(vp);

        /*
         * Check if file_offset page aligned. Currently we cannot handle
         * misalinged file offsets, and so we read in the entire image
         * (what a waste).
         */
        if (file_offset & PAGE_MASK) {
                /* Map text+data read/write/execute */

                /* a_entry is the load address and is page aligned */
                vmaddr = trunc_page(a_out->a_entry);

                /* get anon user mapping, read+write+execute */
                error = vm_map_find(&td->td_proc->p_vmspace->vm_map, NULL, 0,
                    &vmaddr, a_out->a_text + a_out->a_data, 0, VMFS_NO_SPACE,
                    VM_PROT_ALL, VM_PROT_ALL, 0);
                if (error)
                        goto cleanup;

                error = vn_rdwr(UIO_READ, vp, (void *)vmaddr, file_offset,
                    a_out->a_text + a_out->a_data, UIO_USERSPACE, 0,
                    td->td_ucred, NOCRED, &aresid, td);
                if (error != 0)
                        goto cleanup;
                if (aresid != 0) {
                        error = ENOEXEC;
                        goto cleanup;
                }
        } else {
                /*
                 * for QMAGIC, a_entry is 20 bytes beyond the load address
                 * to skip the executable header
                 */
                vmaddr = trunc_page(a_out->a_entry);

                /*
                 * Map it all into the process's space as a single
                 * copy-on-write "data" segment.
                 */
                map = &td->td_proc->p_vmspace->vm_map;
                error = vm_mmap(map, &vmaddr,
                    a_out->a_text + a_out->a_data, VM_PROT_ALL, VM_PROT_ALL,
                    MAP_PRIVATE | MAP_FIXED, OBJT_VNODE, vp, file_offset);
                if (error)
                        goto cleanup;
                vm_map_lock(map);
                if (!vm_map_lookup_entry(map, vmaddr, &entry)) {
                        vm_map_unlock(map);
                        error = EDOOFUS;
                        goto cleanup;
                }
                entry->eflags |= MAP_ENTRY_VN_EXEC;
                vm_map_unlock(map);
                textset = false;
        }

        if (bss_size != 0) {
                /* Calculate BSS start address */
                vmaddr = trunc_page(a_out->a_entry) + a_out->a_text +
                    a_out->a_data;

                /* allocate some 'anon' space */
                error = vm_map_find(&td->td_proc->p_vmspace->vm_map, NULL, 0,
                    &vmaddr, bss_size, 0, VMFS_NO_SPACE, VM_PROT_ALL,
                    VM_PROT_ALL, 0);
                if (error)
                        goto cleanup;
        }

cleanup:
        if (opened) {
                if (locked)
                        VOP_UNLOCK(vp);
                locked = false;
                VOP_CLOSE(vp, FREAD, td->td_ucred, td);
        }
        if (textset) {
                if (!locked) {
                        locked = true;
                        VOP_LOCK(vp, LK_SHARED | LK_RETRY);
                }
                VOP_UNSET_TEXT_CHECKED(vp);
        }
        if (locked)
                VOP_UNLOCK(vp);

        /* Release the temporary mapping. */
        if (a_out)
                kmap_free_wakeup(exec_map, (vm_offset_t)a_out, PAGE_SIZE);

        return (error);
}