FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_emul.c

     /*      $NetBSD: subr_emul.c,v 1.2 2019/01/27 02:08:43 pgoyette Exp $   */
     
     /*-
      * Copyright (c) 1994, 2000, 2005, 2015 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Christos Zoulas and Maxime Villard.
      *
     * 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.
     */
    
    /*
     * Copyright (c) 1996 Christopher G. Demetriou
     * 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.
     * 3. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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(1, "$NetBSD: subr_emul.c,v 1.2 2019/01/27 02:08:43 pgoyette Exp $");
    
    #ifdef _KERNEL_OPT
    #include "opt_pax.h"
    #endif /* _KERNEL_OPT */
    
    #include <sys/param.h>
    #include <sys/proc.h>
    #include <sys/vnode.h>
    #include <sys/namei.h>
    #include <sys/exec.h>
    
    #include <compat/common/compat_util.h>
    
    void
    emul_find_root(struct lwp *l, struct exec_package *epp)
    {
            struct vnode *vp;
            const char *emul_path;
    
            if (epp->ep_emul_root != NULL)
                    /* We've already found it */
                    return;
    
            emul_path = epp->ep_esch->es_emul->e_path;
            if (emul_path == NULL)
                    /* Emulation doesn't have a root */
                    return;
    
            if (namei_simple_kernel(emul_path, NSM_FOLLOW_NOEMULROOT, &vp) != 0)
                    /* emulation root doesn't exist */
                    return;
    
            epp->ep_emul_root = vp;
    }
    
    /*
     * Search the alternate path for dynamic binary interpreter. If not found
     * there, check if the interpreter exists in within 'proper' tree.
     */
   int
   emul_find_interp(struct lwp *l, struct exec_package *epp, const char *itp)
   {
           int error;
           struct pathbuf *pb;
           struct nameidata nd;
           unsigned int flags;
   
           pb = pathbuf_create(itp);
           if (pb == NULL) {
                   return ENOMEM;
           }
   
           /* If we haven't found the emulation root already, do so now */
           /* Maybe we should remember failures somehow ? */
           if (epp->ep_esch->es_emul->e_path != 0 && epp->ep_emul_root == NULL)
                   emul_find_root(l, epp);
   
           if (epp->ep_interp != NULL)
                   vrele(epp->ep_interp);
   
           /* We need to use the emulation root for the new program,
            * not the one for the current process. */
           if (epp->ep_emul_root == NULL)
                   flags = FOLLOW;
           else {
                   nd.ni_erootdir = epp->ep_emul_root;
                   /* hack: Pass in the emulation path for ktrace calls */
                   nd.ni_next = epp->ep_esch->es_emul->e_path;
                   flags = FOLLOW | TRYEMULROOT | EMULROOTSET;
           }
   
           NDINIT(&nd, LOOKUP, flags, pb);
           error = namei(&nd);
           if (error != 0) {
                   epp->ep_interp = NULL;
                   pathbuf_destroy(pb);
                   return error;
           }
   
           /* Save interpreter in case we actually need to load it */
           epp->ep_interp = nd.ni_vp;
   
           pathbuf_destroy(pb);
   
           return 0;
   }

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