FreeBSD/Linux Kernel Cross Reference
sys/compat/linux/common/linux_uselib.c

     /*      $NetBSD: linux_uselib.c,v 1.27 2008/04/28 20:23:44 martin 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 1.27 2008/04/28 20:23:44 martin Exp $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/proc.h>
    #include <sys/malloc.h>
    #include <sys/namei.h>
    #include <sys/vnode.h>
    #include <sys/mount.h>
    #include <sys/exec.h>
    #include <sys/exec_elf.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 nameidata ni;
            struct vnode *vp;
            struct exec hdr;
            struct exec_vmcmd_set vcset;
            int i, magic, error;
            size_t rem;
    
            NDINIT(&ni, LOOKUP, FOLLOW | TRYEMULROOT, UIO_USERSPACE,
               SCARG(uap, path));
   
           if ((error = namei(&ni)))
                   return error;
   
           vp = ni.ni_vp;
   
           if ((error = vn_rdwr(UIO_READ, vp, (void *) &hdr, LINUX_AOUT_HDR_SIZE,
                                0, UIO_SYSSPACE, IO_NODELOCKED, l->l_cred,
                                &rem, NULL))) {
                   vrele(vp);
                   return error;
           }
   
           if (rem != 0) {
                   vrele(vp);
                   return ENOEXEC;
           }
   
           if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE)
                   return ENOEXEC;
   
           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)
                   return (error);
   
           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);
   
           vrele(vp);
   
           return error;
   }

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