darwin-user/mmap.c

   1 /*
   2  *  mmap support for qemu
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <stdarg.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <sys/mman.h>
  26
  27 #include "qemu.h"
  28
  29 //#define DEBUG_MMAP
  30
  31 /* NOTE: all the constants are the HOST ones */
  32 int target_mprotect(unsigned long start, unsigned long len, int prot)
  33 {
  34     unsigned long end, host_start, host_end, addr;
  35     int prot1, ret;
  36
  37 #ifdef DEBUG_MMAP
  38     printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
  39            prot & PROT_READ ? 'r' : '-',
  40            prot & PROT_WRITE ? 'w' : '-',
  41            prot & PROT_EXEC ? 'x' : '-');
  42 #endif
  43
  44     if ((start & ~TARGET_PAGE_MASK) != 0)
  45         return -EINVAL;
  46     len = TARGET_PAGE_ALIGN(len);
  47     end = start + len;
  48     if (end < start)
  49         return -EINVAL;
  50     if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
  51         return -EINVAL;
  52     if (len == 0)
  53         return 0;
  54
  55     host_start = start & qemu_host_page_mask;
  56     host_end = HOST_PAGE_ALIGN(end);
  57     if (start > host_start) {
  58         /* handle host page containing start */
  59         prot1 = prot;
  60         for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
  61             prot1 |= page_get_flags(addr);
  62         }
  63         if (host_end == host_start + qemu_host_page_size) {
  64             for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
  65                 prot1 |= page_get_flags(addr);
  66             }
  67             end = host_end;
  68         }
  69         ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
  70         if (ret != 0)
  71             return ret;
  72         host_start += qemu_host_page_size;
  73     }
  74     if (end < host_end) {
  75         prot1 = prot;
  76         for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
  77             prot1 |= page_get_flags(addr);
  78         }
  79         ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
  80                        prot1 & PAGE_BITS);
  81         if (ret != 0)
  82             return ret;
  83         host_end -= qemu_host_page_size;
  84     }
  85
  86     /* handle the pages in the middle */
  87     if (host_start < host_end) {
  88         ret = mprotect((void *)host_start, host_end - host_start, prot);
  89         if (ret != 0)
  90             return ret;
  91     }
  92     page_set_flags(start, start + len, prot | PAGE_VALID);
  93     return 0;
  94 }
  95
  96 /* map an incomplete host page */
  97 int mmap_frag(unsigned long host_start,
  98                unsigned long start, unsigned long end,
  99                int prot, int flags, int fd, unsigned long offset)
 100 {
 101     unsigned long host_end, ret, addr;
 102     int prot1, prot_new;
 103
 104     host_end = host_start + qemu_host_page_size;
 105
 106     /* get the protection of the target pages outside the mapping */
 107     prot1 = 0;
 108     for(addr = host_start; addr < host_end; addr++) {
 109         if (addr < start || addr >= end)
 110             prot1 |= page_get_flags(addr);
 111     }
 112
 113     if (prot1 == 0) {
 114         /* no page was there, so we allocate one */
 115         ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
 116                          flags | MAP_ANONYMOUS, -1, 0);
 117         if (ret == -1)
 118             return ret;
 119     }
 120     prot1 &= PAGE_BITS;
 121
 122     prot_new = prot | prot1;
 123     if (!(flags & MAP_ANONYMOUS)) {
 124         /* msync() won't work here, so we return an error if write is
 125            possible while it is a shared mapping */
 126 #ifndef __APPLE__
 127         if ((flags & MAP_TYPE) == MAP_SHARED &&
 128 #else
 129         if ((flags &  MAP_SHARED) &&
 130 #endif
 131             (prot & PROT_WRITE))
 132             return -EINVAL;
 133
 134         /* adjust protection to be able to read */
 135         if (!(prot1 & PROT_WRITE))
 136             mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
 137
 138         /* read the corresponding file data */
 139         pread(fd, (void *)start, end - start, offset);
 140
 141         /* put final protection */
 142         if (prot_new != (prot1 | PROT_WRITE))
 143             mprotect((void *)host_start, qemu_host_page_size, prot_new);
 144     } else {
 145         /* just update the protection */
 146         if (prot_new != prot1) {
 147             mprotect((void *)host_start, qemu_host_page_size, prot_new);
 148         }
 149     }
 150     return 0;
 151 }
 152
 153 /* NOTE: all the constants are the HOST ones */
 154 long target_mmap(unsigned long start, unsigned long len, int prot,
 155                  int flags, int fd, unsigned long offset)
 156 {
 157     unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
 158 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
 159     static unsigned long last_start = 0x40000000;
 160 #endif
 161
 162 #ifdef DEBUG_MMAP
 163     {
 164         printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
 165                start, len,
 166                prot & PROT_READ ? 'r' : '-',
 167                prot & PROT_WRITE ? 'w' : '-',
 168                prot & PROT_EXEC ? 'x' : '-');
 169         if (flags & MAP_FIXED)
 170             printf("MAP_FIXED ");
 171         if (flags & MAP_ANONYMOUS)
 172             printf("MAP_ANON ");
 173 #ifndef MAP_TYPE
 174 # define MAP_TYPE 0x3
 175 #endif
 176         switch(flags & MAP_TYPE) {
 177         case MAP_PRIVATE:
 178             printf("MAP_PRIVATE ");
 179             break;
 180         case MAP_SHARED:
 181             printf("MAP_SHARED ");
 182             break;
 183         default:
 184             printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
 185             break;
 186         }
 187         printf("fd=%d offset=%lx\n", fd, offset);
 188     }
 189 #endif
 190
 191     if (offset & ~TARGET_PAGE_MASK)
 192         return -EINVAL;
 193
 194     len = TARGET_PAGE_ALIGN(len);
 195     if (len == 0)
 196         return start;
 197     host_start = start & qemu_host_page_mask;
 198
 199     if (!(flags & MAP_FIXED)) {
 200 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
 201         /* tell the kernel to search at the same place as i386 */
 202         if (host_start == 0) {
 203             host_start = last_start;
 204             last_start += HOST_PAGE_ALIGN(len);
 205         }
 206 #endif
 207         if (qemu_host_page_size != qemu_real_host_page_size) {
 208             /* NOTE: this code is only for debugging with '-p' option */
 209             /* reserve a memory area */
 210             host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
 211             host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
 212                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 213             if (host_start == -1)
 214                 return host_start;
 215             host_end = host_start + host_len;
 216             start = HOST_PAGE_ALIGN(host_start);
 217             end = start + HOST_PAGE_ALIGN(len);
 218             if (start > host_start)
 219                 munmap((void *)host_start, start - host_start);
 220             if (end < host_end)
 221                 munmap((void *)end, host_end - end);
 222             /* use it as a fixed mapping */
 223             flags |= MAP_FIXED;
 224         } else {
 225             /* if not fixed, no need to do anything */
 226             host_offset = offset & qemu_host_page_mask;
 227             host_len = len + offset - host_offset;
 228             start = (long)mmap((void *)host_start, host_len,
 229                                prot, flags, fd, host_offset);
 230             if (start == -1)
 231                 return start;
 232             /* update start so that it points to the file position at 'offset' */
 233             if (!(flags & MAP_ANONYMOUS))
 234                 start += offset - host_offset;
 235             goto the_end1;
 236         }
 237     }
 238
 239     if (start & ~TARGET_PAGE_MASK)
 240         return -EINVAL;
 241     end = start + len;
 242     host_end = HOST_PAGE_ALIGN(end);
 243
 244     /* worst case: we cannot map the file because the offset is not
 245        aligned, so we read it */
 246     if (!(flags & MAP_ANONYMOUS) &&
 247         (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
 248         /* msync() won't work here, so we return an error if write is
 249            possible while it is a shared mapping */
 250 #ifndef __APPLE__
 251         if ((flags & MAP_TYPE) == MAP_SHARED &&
 252 #else
 253         if ((flags & MAP_SHARED) &&
 254 #endif
 255             (prot & PROT_WRITE))
 256             return -EINVAL;
 257         retaddr = target_mmap(start, len, prot | PROT_WRITE,
 258                               MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
 259                               -1, 0);
 260         if (retaddr == -1)
 261             return retaddr;
 262         pread(fd, (void *)start, len, offset);
 263         if (!(prot & PROT_WRITE)) {
 264             ret = target_mprotect(start, len, prot);
 265             if (ret != 0)
 266                 return ret;
 267         }
 268         goto the_end;
 269     }
 270
 271     /* handle the start of the mapping */
 272     if (start > host_start) {
 273         if (host_end == host_start + qemu_host_page_size) {
 274             /* one single host page */
 275             ret = mmap_frag(host_start, start, end,
 276                             prot, flags, fd, offset);
 277             if (ret == -1)
 278                 return ret;
 279             goto the_end1;
 280         }
 281         ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
 282                         prot, flags, fd, offset);
 283         if (ret == -1)
 284             return ret;
 285         host_start += qemu_host_page_size;
 286     }
 287     /* handle the end of the mapping */
 288     if (end < host_end) {
 289         ret = mmap_frag(host_end - qemu_host_page_size,
 290                         host_end - qemu_host_page_size, host_end,
 291                         prot, flags, fd,
 292                         offset + host_end - qemu_host_page_size - start);
 293         if (ret == -1)
 294             return ret;
 295         host_end -= qemu_host_page_size;
 296     }
 297
 298     /* map the middle (easier) */
 299     if (host_start < host_end) {
 300         unsigned long offset1;
 301         if (flags & MAP_ANONYMOUS)
 302           offset1 = 0;
 303         else
 304           offset1 = offset + host_start - start;
 305         ret = (long)mmap((void *)host_start, host_end - host_start,
 306                          prot, flags, fd, offset1);
 307         if (ret == -1)
 308             return ret;
 309     }
 310  the_end1:
 311     page_set_flags(start, start + len, prot | PAGE_VALID);
 312  the_end:
 313 #ifdef DEBUG_MMAP
 314     printf("target_mmap: ret=0x%lx\n", (long)start);
 315     page_dump(stdout);
 316     printf("\n");
 317 #endif
 318     return start;
 319 }
 320
 321 int target_munmap(unsigned long start, unsigned long len)
 322 {
 323     unsigned long end, host_start, host_end, addr;
 324     int prot, ret;
 325
 326 #ifdef DEBUG_MMAP
 327     printf("munmap: start=0x%lx len=0x%lx\n", start, len);
 328 #endif
 329     if (start & ~TARGET_PAGE_MASK)
 330         return -EINVAL;
 331     len = TARGET_PAGE_ALIGN(len);
 332     if (len == 0)
 333         return -EINVAL;
 334     end = start + len;
 335     host_start = start & qemu_host_page_mask;
 336     host_end = HOST_PAGE_ALIGN(end);
 337
 338     if (start > host_start) {
 339         /* handle host page containing start */
 340         prot = 0;
 341         for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
 342             prot |= page_get_flags(addr);
 343         }
 344         if (host_end == host_start + qemu_host_page_size) {
 345             for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
 346                 prot |= page_get_flags(addr);
 347             }
 348             end = host_end;
 349         }
 350         if (prot != 0)
 351             host_start += qemu_host_page_size;
 352     }
 353     if (end < host_end) {
 354         prot = 0;
 355         for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
 356             prot |= page_get_flags(addr);
 357         }
 358         if (prot != 0)
 359             host_end -= qemu_host_page_size;
 360     }
 361
 362     /* unmap what we can */
 363     if (host_start < host_end) {
 364         ret = munmap((void *)host_start, host_end - host_start);
 365         if (ret != 0)
 366             return ret;
 367     }
 368
 369     page_set_flags(start, start + len, 0);
 370     return 0;
 371 }
 372
 373 /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
 374    blocks which have been allocated starting on a host page */
 375 long target_mremap(unsigned long old_addr, unsigned long old_size,
 376                    unsigned long new_size, unsigned long flags,
 377                    unsigned long new_addr)
 378 {
 379 #ifndef __APPLE__
 380     /* XXX: use 5 args syscall */
 381     new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
 382     if (new_addr == -1)
 383         return new_addr;
 384     prot = page_get_flags(old_addr);
 385     page_set_flags(old_addr, old_addr + old_size, 0);
 386     page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
 387     return new_addr;
 388 #else
 389     qerror("target_mremap: unsupported\n");
 390 #endif
 391
 392 }
 393
 394 int target_msync(unsigned long start, unsigned long len, int flags)
 395 {
 396     unsigned long end;
 397
 398     if (start & ~TARGET_PAGE_MASK)
 399         return -EINVAL;
 400     len = TARGET_PAGE_ALIGN(len);
 401     end = start + len;
 402     if (end < start)
 403         return -EINVAL;
 404     if (end == start)
 405         return 0;
 406
 407     start &= qemu_host_page_mask;
 408     return msync((void *)start, end - start, flags);
 409 }