sys/kern/imgact_aout.c

   1 /*-
   2  * Copyright (c) 1993, David Greenman
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/exec.h>
  32 #include <sys/imgact.h>
  33 #include <sys/imgact_aout.h>
  34 #include <sys/kernel.h>
  35 #include <sys/lock.h>
  36 #include <sys/malloc.h>
  37 #include <sys/mutex.h>
  38 #include <sys/proc.h>
  39 #include <sys/resourcevar.h>
  40 #include <sys/signalvar.h>
  41 #include <sys/syscall.h>
  42 #include <sys/sysent.h>
  43 #include <sys/systm.h>
  44 #include <sys/vnode.h>
  45
  46 #include <machine/frame.h>
  47 #include <machine/md_var.h>
  48
  49 #include <vm/vm.h>
  50 #include <vm/pmap.h>
  51 #include <vm/vm_map.h>
  52 #include <vm/vm_object.h>
  53 #include <vm/vm_param.h>
  54
  55 static int      exec_aout_imgact(struct image_params *imgp);
  56 static int      aout_fixup(register_t **stack_base, struct image_params *imgp);
  57
  58 struct sysentvec aout_sysvec = {
  59         SYS_MAXSYSCALL,
  60         sysent,
  61         0,
  62         0,
  63         NULL,
  64         0,
  65         NULL,
  66         NULL,
  67         aout_fixup,
  68         sendsig,
  69         sigcode,
  70         &szsigcode,
  71         NULL,
  72         "FreeBSD a.out",
  73         NULL,
  74         NULL,
  75         MINSIGSTKSZ,
  76         PAGE_SIZE,
  77         VM_MIN_ADDRESS,
  78         VM_MAXUSER_ADDRESS,
  79         USRSTACK,
  80         PS_STRINGS,
  81         VM_PROT_ALL,
  82         exec_copyout_strings,
  83         exec_setregs,
  84         NULL
  85 };
  86
  87 static int
  88 aout_fixup(stack_base, imgp)
  89         register_t **stack_base;
  90         struct image_params *imgp;
  91 {
  92
  93         return (suword(--(*stack_base), imgp->args->argc));
  94 }
  95
  96 static int
  97 exec_aout_imgact(imgp)
  98         struct image_params *imgp;
  99 {
 100         const struct exec *a_out = (const struct exec *) imgp->image_header;
 101         struct vmspace *vmspace;
 102         vm_map_t map;
 103         vm_object_t object;
 104         vm_offset_t text_end, data_end;
 105         unsigned long virtual_offset;
 106         unsigned long file_offset;
 107         unsigned long bss_size;
 108         int error;
 109
 110         /*
 111          * Linux and *BSD binaries look very much alike,
 112          * only the machine id is different:
 113          * 0x64 for Linux, 0x86 for *BSD, 0x00 for BSDI.
 114          * NetBSD is in network byte order.. ugh.
 115          */
 116         if (((a_out->a_magic >> 16) & 0xff) != 0x86 &&
 117             ((a_out->a_magic >> 16) & 0xff) != 0 &&
 118             ((((int)ntohl(a_out->a_magic)) >> 16) & 0xff) != 0x86)
 119                 return -1;
 120
 121         /*
 122          * Set file/virtual offset based on a.out variant.
 123          *      We do two cases: host byte order and network byte order
 124          *      (for NetBSD compatibility)
 125          */
 126         switch ((int)(a_out->a_magic & 0xffff)) {
 127         case ZMAGIC:
 128                 virtual_offset = 0;
 129                 if (a_out->a_text) {
 130                         file_offset = PAGE_SIZE;
 131                 } else {
 132                         /* Bill's "screwball mode" */
 133                         file_offset = 0;
 134                 }
 135                 break;
 136         case QMAGIC:
 137                 virtual_offset = PAGE_SIZE;
 138                 file_offset = 0;
 139                 /* Pass PS_STRINGS for BSD/OS binaries only. */
 140                 if (N_GETMID(*a_out) == MID_ZERO)
 141                         imgp->ps_strings = aout_sysvec.sv_psstrings;
 142                 break;
 143         default:
 144                 /* NetBSD compatibility */
 145                 switch ((int)(ntohl(a_out->a_magic) & 0xffff)) {
 146                 case ZMAGIC:
 147                 case QMAGIC:
 148                         virtual_offset = PAGE_SIZE;
 149                         file_offset = 0;
 150                         break;
 151                 default:
 152                         return (-1);
 153                 }
 154         }
 155
 156         bss_size = roundup(a_out->a_bss, PAGE_SIZE);
 157
 158         /*
 159          * Check various fields in header for validity/bounds.
 160          */
 161         if (/* entry point must lay with text region */
 162             a_out->a_entry < virtual_offset ||
 163             a_out->a_entry >= virtual_offset + a_out->a_text ||
 164
 165             /* text and data size must each be page rounded */
 166             a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK)
 167                 return (-1);
 168
 169         /* text + data can't exceed file size */
 170         if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
 171                 return (EFAULT);
 172
 173         /*
 174          * text/data/bss must not exceed limits
 175          */
 176         PROC_LOCK(imgp->proc);
 177         if (/* text can't exceed maximum text size */
 178             a_out->a_text > maxtsiz ||
 179
 180             /* data + bss can't exceed rlimit */
 181             a_out->a_data + bss_size > lim_cur(imgp->proc, RLIMIT_DATA)) {
 182                         PROC_UNLOCK(imgp->proc);
 183                         return (ENOMEM);
 184         }
 185         PROC_UNLOCK(imgp->proc);
 186
 187         /*
 188          * Avoid a possible deadlock if the current address space is destroyed
 189          * and that address space maps the locked vnode.  In the common case,
 190          * the locked vnode's v_usecount is decremented but remains greater
 191          * than zero.  Consequently, the vnode lock is not needed by vrele().
 192          * However, in cases where the vnode lock is external, such as nullfs,
 193          * v_usecount may become zero.
 194          */
 195         VOP_UNLOCK(imgp->vp, 0);
 196
 197         /*
 198          * Destroy old process VM and create a new one (with a new stack)
 199          */
 200         error = exec_new_vmspace(imgp, &aout_sysvec);
 201
 202         vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
 203         if (error)
 204                 return (error);
 205
 206         /*
 207          * The vm space can be changed by exec_new_vmspace
 208          */
 209         vmspace = imgp->proc->p_vmspace;
 210
 211         object = imgp->object;
 212         map = &vmspace->vm_map;
 213         vm_map_lock(map);
 214         vm_object_reference(object);
 215
 216         text_end = virtual_offset + a_out->a_text;
 217         error = vm_map_insert(map, object,
 218                 file_offset,
 219                 virtual_offset, text_end,
 220                 VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
 221                 MAP_COPY_ON_WRITE | MAP_PREFAULT);
 222         if (error) {
 223                 vm_map_unlock(map);
 224                 vm_object_deallocate(object);
 225                 return (error);
 226         }
 227         data_end = text_end + a_out->a_data;
 228         if (a_out->a_data) {
 229                 vm_object_reference(object);
 230                 error = vm_map_insert(map, object,
 231                         file_offset + a_out->a_text,
 232                         text_end, data_end,
 233                         VM_PROT_ALL, VM_PROT_ALL,
 234                         MAP_COPY_ON_WRITE | MAP_PREFAULT);
 235                 if (error) {
 236                         vm_map_unlock(map);
 237                         vm_object_deallocate(object);
 238                         return (error);
 239                 }
 240         }
 241
 242         if (bss_size) {
 243                 error = vm_map_insert(map, NULL, 0,
 244                         data_end, data_end + bss_size,
 245                         VM_PROT_ALL, VM_PROT_ALL, 0);
 246                 if (error) {
 247                         vm_map_unlock(map);
 248                         return (error);
 249                 }
 250         }
 251         vm_map_unlock(map);
 252
 253         /* Fill in process VM information */
 254         vmspace->vm_tsize = a_out->a_text >> PAGE_SHIFT;
 255         vmspace->vm_dsize = (a_out->a_data + bss_size) >> PAGE_SHIFT;
 256         vmspace->vm_taddr = (caddr_t) (uintptr_t) virtual_offset;
 257         vmspace->vm_daddr = (caddr_t) (uintptr_t)
 258                             (virtual_offset + a_out->a_text);
 259
 260         /* Fill in image_params */
 261         imgp->interpreted = 0;
 262         imgp->entry_addr = a_out->a_entry;
 263
 264         imgp->proc->p_sysent = &aout_sysvec;
 265
 266         return (0);
 267 }
 268
 269 /*
 270  * Tell kern_execve.c about it, with a little help from the linker.
 271  */
 272 static struct execsw aout_execsw = { exec_aout_imgact, "a.out" };
 273 EXEC_SET(aout, aout_execsw);