sys/vfs/procfs/procfs_map.c

   1 /*
   2  * Copyright (c) 1993 Jan-Simon Pendry
   3  * Copyright (c) 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Jan-Simon Pendry.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)procfs_status.c     8.3 (Berkeley) 2/17/94
  34  *
  35  * $FreeBSD: src/sys/miscfs/procfs/procfs_map.c,v 1.24.2.1 2001/08/04 13:12:24 rwatson Exp $
  36  * $DragonFly: src/sys/vfs/procfs/procfs_map.c,v 1.7 2007/02/19 01:14:24 corecode Exp $
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/proc.h>
  42 #include <sys/vnode.h>
  43 #include <vfs/procfs/procfs.h>
  44
  45 #include <vm/vm.h>
  46 #include <sys/lock.h>
  47 #include <vm/pmap.h>
  48 #include <vm/vm_map.h>
  49 #include <vm/vm_page.h>
  50 #include <vm/vm_object.h>
  51
  52
  53 #define MEBUFFERSIZE 256
  54
  55 /*
  56  * The map entries can *almost* be read with programs like cat.  However,
  57  * large maps need special programs to read.  It is not easy to implement
  58  * a program that can sense the required size of the buffer, and then
  59  * subsequently do a read with the appropriate size.  This operation cannot
  60  * be atomic.  The best that we can do is to allow the program to do a read
  61  * with an arbitrarily large buffer, and return as much as we can.  We can
  62  * return an error code if the buffer is too small (EFBIG), then the program
  63  * can try a bigger buffer.
  64  */
  65 int
  66 procfs_domap(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
  67              struct uio *uio)
  68 {
  69         struct proc *p = lp->lwp_proc;
  70         int len;
  71         struct vnode *vp;
  72         char *fullpath, *freepath;
  73         int error;
  74         vm_map_t map = &p->p_vmspace->vm_map;
  75         pmap_t pmap = vmspace_pmap(p->p_vmspace);
  76         vm_map_entry_t entry;
  77         char mebuffer[MEBUFFERSIZE];
  78
  79         if (uio->uio_rw != UIO_READ)
  80                 return (EOPNOTSUPP);
  81
  82         if (uio->uio_offset != 0)
  83                 return (0);
  84
  85         error = 0;
  86         vm_map_lock_read(map);
  87         for (entry = map->header.next;
  88                 ((uio->uio_resid > 0) && (entry != &map->header));
  89                 entry = entry->next) {
  90                 vm_object_t obj, tobj, lobj;
  91                 int ref_count, shadow_count, flags;
  92                 vm_offset_t addr;
  93                 vm_offset_t ostart;
  94                 int resident, privateresident;
  95                 char *type;
  96
  97                 if (entry->maptype != VM_MAPTYPE_NORMAL &&
  98                     entry->maptype != VM_MAPTYPE_VPAGETABLE) {
  99                         continue;
 100                 }
 101
 102                 obj = entry->object.vm_object;
 103                 if (obj)
 104                         vm_object_hold(obj);
 105
 106                 if (obj && (obj->shadow_count == 1))
 107                         privateresident = obj->resident_page_count;
 108                 else
 109                         privateresident = 0;
 110
 111                 /*
 112                  * Use map->hint as a poor man's ripout detector.
 113                  */
 114                 map->hint = entry;
 115                 ostart = entry->start;
 116
 117                 /*
 118                  * Count resident pages (XXX can be horrible on 64-bit)
 119                  */
 120                 resident = 0;
 121                 addr = entry->start;
 122                 while (addr < entry->end) {
 123                         if (pmap_extract(pmap, addr))
 124                                 resident++;
 125                         addr += PAGE_SIZE;
 126                 }
 127                 if (obj) {
 128                         lobj = obj;
 129                         while ((tobj = lobj->backing_object) != NULL) {
 130                                 KKASSERT(tobj != obj);
 131                                 vm_object_hold(tobj);
 132                                 if (tobj == lobj->backing_object) {
 133                                         if (lobj != obj) {
 134                                                 vm_object_lock_swap();
 135                                                 vm_object_drop(lobj);
 136                                         }
 137                                         lobj = tobj;
 138                                 } else {
 139                                         vm_object_drop(tobj);
 140                                 }
 141                         }
 142                 } else {
 143                         lobj = NULL;
 144                 }
 145
 146                 freepath = NULL;
 147                 fullpath = "-";
 148                 if (lobj) {
 149                         switch(lobj->type) {
 150                         default:
 151                         case OBJT_DEFAULT:
 152                                 type = "default";
 153                                 vp = NULL;
 154                                 break;
 155                         case OBJT_VNODE:
 156                                 type = "vnode";
 157                                 vp = lobj->handle;
 158                                 vref(vp);
 159                                 break;
 160                         case OBJT_SWAP:
 161                                 type = "swap";
 162                                 vp = NULL;
 163                                 break;
 164                         case OBJT_DEVICE:
 165                                 type = "device";
 166                                 vp = NULL;
 167                                 break;
 168                         }
 169
 170                         flags = obj->flags;
 171                         ref_count = obj->ref_count;
 172                         shadow_count = obj->shadow_count;
 173                         if (vp != NULL) {
 174                                 vn_fullpath(p, vp, &fullpath, &freepath, 1);
 175                                 vrele(vp);
 176                         }
 177                         if (lobj != obj)
 178                                 vm_object_drop(lobj);
 179                 } else {
 180                         type = "none";
 181                         flags = 0;
 182                         ref_count = 0;
 183                         shadow_count = 0;
 184                 }
 185
 186                 /*
 187                  * format:
 188                  *  start, end, res, priv res, cow, access, type, (fullpath).
 189                  */
 190                 ksnprintf(mebuffer, sizeof(mebuffer),
 191                     "0x%lx 0x%lx %d %d %p %s%s%s %d %d 0x%x %s %s %s %s\n",
 192                         (u_long)entry->start, (u_long)entry->end,
 193                         resident, privateresident, obj,
 194                         (entry->protection & VM_PROT_READ)?"r":"-",
 195                         (entry->protection & VM_PROT_WRITE)?"w":"-",
 196                         (entry->protection & VM_PROT_EXECUTE)?"x":"-",
 197                         ref_count, shadow_count, flags,
 198                         (entry->eflags & MAP_ENTRY_COW)?"COW":"NCOW",
 199                         (entry->eflags & MAP_ENTRY_NEEDS_COPY)?"NC":"NNC",
 200                         type, fullpath);
 201
 202                 if (obj)
 203                         vm_object_drop(obj);
 204
 205                 if (freepath != NULL) {
 206                         kfree(freepath, M_TEMP);
 207                         freepath = NULL;
 208                 }
 209
 210                 len = strlen(mebuffer);
 211                 if (len > uio->uio_resid) {
 212                         error = EFBIG;
 213                         break;
 214                 }
 215
 216                 /*
 217                  * We cannot safely hold the map locked while accessing
 218                  * userspace as a VM fault might recurse the locked map.
 219                  */
 220                 vm_map_unlock_read(map);
 221                 error = uiomove(mebuffer, len, uio);
 222                 vm_map_lock_read(map);
 223                 if (error)
 224                         break;
 225
 226                 /*
 227                  * We use map->hint as a poor man's ripout detector.  If
 228                  * it does not match the entry we set it to prior to
 229                  * unlocking the map the entry MIGHT now be stale.  In
 230                  * this case we do an expensive lookup to find our place
 231                  * in the iteration again.
 232                  */
 233                 if (map->hint != entry) {
 234                         vm_map_entry_t reentry;
 235
 236                         vm_map_lookup_entry(map, ostart, &reentry);
 237                         entry = reentry;
 238                 }
 239         }
 240         vm_map_unlock_read(map);
 241
 242         return error;
 243 }
 244
 245 int
 246 procfs_validmap(struct lwp *lp)
 247 {
 248         return ((lp->lwp_proc->p_flag & P_SYSTEM) == 0);
 249 }