The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/i386/linux/imgact_linux.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 1994-1996 Søren Schmidt
    5  * All rights reserved.
    6  *
    7  * Based heavily on /sys/kern/imgact_aout.c which is:
    8  * Copyright (c) 1993, David Greenman
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD$");
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/exec.h>
   38 #include <sys/imgact.h>
   39 #include <sys/imgact_aout.h>
   40 #include <sys/kernel.h>
   41 #include <sys/lock.h>
   42 #include <sys/mman.h>
   43 #include <sys/mutex.h>
   44 #include <sys/proc.h>
   45 #include <sys/racct.h>
   46 #include <sys/resourcevar.h>
   47 #include <sys/vnode.h>
   48 
   49 #include <vm/vm.h>
   50 #include <vm/vm_kern.h>
   51 #include <vm/vm_param.h>
   52 #include <vm/pmap.h>
   53 #include <vm/vm_map.h>
   54 #include <vm/vm_extern.h>
   55 
   56 #include <i386/linux/linux.h>
   57 
   58 static int      exec_linux_imgact(struct image_params *iparams);
   59 
   60 static int
   61 exec_linux_imgact(struct image_params *imgp)
   62 {
   63         const struct exec *a_out = (const struct exec *) imgp->image_header;
   64         struct vmspace *vmspace;
   65         vm_offset_t vmaddr;
   66         unsigned long virtual_offset, file_offset;
   67         unsigned long bss_size;
   68         ssize_t aresid;
   69         int error;
   70 
   71         if (((a_out->a_magic >> 16) & 0xff) != 0x64)
   72                 return (-1);
   73 
   74         /*
   75          * Set file/virtual offset based on a.out variant.
   76          */
   77         switch ((int)(a_out->a_magic & 0xffff)) {
   78         case 0413:
   79                 virtual_offset = 0;
   80                 file_offset = 1024;
   81                 break;
   82         case 0314:
   83                 virtual_offset = 4096;
   84                 file_offset = 0;
   85                 break;
   86         default:
   87                 return (-1);
   88         }
   89         bss_size = round_page(a_out->a_bss);
   90 #ifdef DEBUG
   91         printf("imgact: text: %08lx, data: %08lx, bss: %08lx\n",
   92             (u_long)a_out->a_text, (u_long)a_out->a_data, bss_size);
   93 #endif
   94 
   95         /*
   96          * Check various fields in header for validity/bounds.
   97          */
   98         if (a_out->a_entry < virtual_offset ||
   99             a_out->a_entry >= virtual_offset + a_out->a_text ||
  100             a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK)
  101                 return (-1);
  102 
  103         /* text + data can't exceed file size */
  104         if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
  105                 return (EFAULT);
  106         /*
  107          * text/data/bss must not exceed limits
  108          */
  109         PROC_LOCK(imgp->proc);
  110         if (a_out->a_text > maxtsiz ||
  111             a_out->a_data + bss_size > lim_cur_proc(imgp->proc, RLIMIT_DATA) ||
  112             racct_set(imgp->proc, RACCT_DATA, a_out->a_data + bss_size) != 0) {
  113                 PROC_UNLOCK(imgp->proc);
  114                 return (ENOMEM);
  115         }
  116         PROC_UNLOCK(imgp->proc);
  117 
  118         VOP_UNLOCK(imgp->vp);
  119 
  120         /*
  121          * Destroy old process VM and create a new one (with a new stack)
  122          */
  123         error = exec_new_vmspace(imgp, &linux_sysvec);
  124         if (error)
  125                 goto fail;
  126         vmspace = imgp->proc->p_vmspace;
  127 
  128         /*
  129          * Check if file_offset page aligned,.
  130          * Currently we cannot handle misaligned file offsets,
  131          * and so we read in the entire image (what a waste).
  132          */
  133         if (file_offset & PAGE_MASK) {
  134 #ifdef DEBUG
  135                 printf("imgact: Non page aligned binary %lu\n", file_offset);
  136 #endif
  137                 /*
  138                  * Map text+data+bss read/write/execute
  139                  */
  140                 vmaddr = virtual_offset;
  141                 error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
  142                     a_out->a_text + a_out->a_data + bss_size, 0, VMFS_NO_SPACE,
  143                     VM_PROT_ALL, VM_PROT_ALL, 0);
  144                 if (error)
  145                         goto fail;
  146 
  147                 error = vn_rdwr(UIO_READ, imgp->vp, (void *)vmaddr, file_offset,
  148                     a_out->a_text + a_out->a_data, UIO_USERSPACE, 0,
  149                     curthread->td_ucred, NOCRED, &aresid, curthread);
  150                 if (error != 0)
  151                         goto fail;
  152                 if (aresid != 0) {
  153                         error = ENOEXEC;
  154                         goto fail;
  155                 }
  156 
  157                 /*
  158                  * remove write enable on the 'text' part
  159                  */
  160                 error = vm_map_protect(&vmspace->vm_map, vmaddr,
  161                     vmaddr + a_out->a_text, 0, VM_PROT_EXECUTE | VM_PROT_READ,
  162                     VM_MAP_PROTECT_SET_MAXPROT);
  163                 if (error)
  164                         goto fail;
  165         } else {
  166 #ifdef DEBUG
  167                 printf("imgact: Page aligned binary %lu\n", file_offset);
  168 #endif
  169                 /*
  170                  * Map text+data read/execute
  171                  */
  172                 vmaddr = virtual_offset;
  173                 error = vm_mmap(&vmspace->vm_map, &vmaddr,
  174                     a_out->a_text + a_out->a_data,
  175                     VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
  176                     MAP_PRIVATE | MAP_FIXED, OBJT_VNODE, imgp->vp, file_offset);
  177                 if (error)
  178                         goto fail;
  179 
  180 #ifdef DEBUG
  181                 printf("imgact: startaddr=%08lx, length=%08lx\n",
  182                     (u_long)vmaddr,
  183                     (u_long)a_out->a_text + (u_long)a_out->a_data);
  184 #endif
  185                 /*
  186                  * allow read/write of data
  187                  */
  188                 error = vm_map_protect(&vmspace->vm_map, vmaddr + a_out->a_text,
  189                     vmaddr + a_out->a_text + a_out->a_data, VM_PROT_ALL, 0,
  190                     VM_MAP_PROTECT_SET_PROT);
  191                 if (error)
  192                         goto fail;
  193 
  194                 /*
  195                  * Allocate anon demand-zeroed area for uninitialized data
  196                  */
  197                 if (bss_size != 0) {
  198                         vmaddr = virtual_offset + a_out->a_text + a_out->a_data;
  199                 error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
  200                     bss_size, 0, VMFS_NO_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0);
  201                 if (error)
  202                         goto fail;
  203 #ifdef DEBUG
  204                 printf("imgact: bssaddr=%08lx, length=%08lx\n", (u_long)vmaddr,
  205                     bss_size);
  206 #endif
  207                 }
  208         }
  209         /* Fill in process VM information */
  210         vmspace->vm_tsize = round_page(a_out->a_text) >> PAGE_SHIFT;
  211         vmspace->vm_dsize = round_page(a_out->a_data + bss_size) >> PAGE_SHIFT;
  212         vmspace->vm_taddr = (caddr_t)(void *)(uintptr_t)virtual_offset;
  213         vmspace->vm_daddr =
  214             (caddr_t)(void *)(uintptr_t)(virtual_offset + a_out->a_text);
  215 
  216         /* Fill in image_params */
  217         imgp->interpreted = 0;
  218         imgp->entry_addr = a_out->a_entry;
  219 
  220         imgp->proc->p_sysent = &linux_sysvec;
  221 
  222 fail:
  223         vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
  224         return (error);
  225 }
  226 
  227 /*
  228  * Tell kern_execve.c about it, with a little help from the linker.
  229  */
  230 static struct execsw linux_execsw = { exec_linux_imgact, "Linux a.out" };
  231 EXEC_SET(linuxaout, linux_execsw);

Cache object: e4befba133670859ff4b476c6924a8ab


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