/*      $NetBSD: linux_uselib.c,v 1.33 2014/11/09 17:48:08 maxv Exp $   */

/*-
* Copyright (c) 1995, 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas, Frank van der Linden and Eric Haszlakiewicz.
*
* 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_uselib.c,v 1.33 2014/11/09 17:48:08 maxv Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/exec.h>
#include <sys/exec_aout.h>

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

#include <sys/cpu.h>
#include <machine/reg.h>

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

#ifndef EXEC_AOUT
/* define EXEC_AOUT to get prototype from linux_syscall.h */
#define EXEC_AOUT
#endif

#include <compat/linux/linux_syscallargs.h>
#include <compat/linux/linux_syscall.h>

/*
* The Linux system call to load shared libraries, a.out version. The
* a.out shared libs are just files that are mapped onto a fixed
* address in the process' address space. The address is given in
* a_entry. Read in the header, set up some VM commands and run them.
*
* Yes, both text and data are mapped at once, so we're left with
* writable text for the shared libs. The Linux crt0 seemed to break
* sometimes when data was mapped separately. It munmapped a uselib()
* of ld.so by hand, which failed with shared text and data for ld.so
* Yuck.
*
* Because of the problem with ZMAGIC executables (text starts
* at 0x400 in the file, but needs to be mapped at 0), ZMAGIC
* shared libs are not handled very efficiently :-(
*/

int
linux_sys_uselib(struct lwp *l, const struct linux_sys_uselib_args *uap, register_t *retval)
{
       /* {
               syscallarg(const char *) path;
       } */
       long bsize, dsize, tsize, taddr, baddr, daddr;
       struct vnode *vp;
       struct exec hdr;
       struct exec_vmcmd_set vcset;
       int i, magic, error;
       size_t rem;

       error = namei_simple_user(SCARG(uap, path),
                               NSM_FOLLOW_TRYEMULROOT, &vp);
       if (error != 0)
               return error;

       if (vp->v_type != VREG) {
               error = EINVAL;
               goto out;
       }

       if ((error = vn_rdwr(UIO_READ, vp, (void *) &hdr, LINUX_AOUT_HDR_SIZE,
                            0, UIO_SYSSPACE, IO_NODELOCKED, l->l_cred,
                            &rem, NULL))) {
               goto out;
       }

       if (rem != 0) {
               error = ENOEXEC;
               goto out;
       }

       if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE) {
               error = ENOEXEC;
               goto out;
       }

       magic = LINUX_N_MAGIC(&hdr);
       taddr = hdr.a_entry & (~(PAGE_SIZE - 1));
       tsize = hdr.a_text;
       daddr = taddr + tsize;
       dsize = hdr.a_data + hdr.a_bss;

       error = vn_marktext(vp);
       if (error)
               goto out;

       vcset.evs_cnt = 0;
       vcset.evs_used = 0;

       NEW_VMCMD(&vcset,
                 magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
                 hdr.a_text + hdr.a_data, taddr,
                 vp, LINUX_N_TXTOFF(hdr, magic),
                 VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);

       baddr = roundup(daddr + hdr.a_data, PAGE_SIZE);
       bsize = daddr + dsize - baddr;
       if (bsize > 0) {
               NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
                   NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
       }

       for (i = 0; i < vcset.evs_used && !error; i++) {
               struct exec_vmcmd *vcp;

               vcp = &vcset.evs_cmds[i];
               error = (*vcp->ev_proc)(l, vcp);
       }

       kill_vmcmds(&vcset);

out:
       vrele(vp);
       return error;
}