File:  [Qemu by Fabrice Bellard] / qemu / darwin-user / mmap.c
Revision 1.1.1.3 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 16:55:09 2018 UTC (3 years, 3 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu0105, qemu0104, qemu0103, qemu0102, qemu0101, qemu0100, HEAD
qemu 0.10.0

    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, write to the Free Software
   18:  *  Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   19:  *  MA 02110-1301, USA.
   20:  */
   21: #include <stdlib.h>
   22: #include <stdio.h>
   23: #include <stdarg.h>
   24: #include <string.h>
   25: #include <unistd.h>
   26: #include <errno.h>
   27: #include <sys/mman.h>
   28: 
   29: #include "qemu.h"
   30: 
   31: //#define DEBUG_MMAP
   32: 
   33: /* NOTE: all the constants are the HOST ones */
   34: int target_mprotect(unsigned long start, unsigned long len, int prot)
   35: {
   36:     unsigned long end, host_start, host_end, addr;
   37:     int prot1, ret;
   38: 
   39: #ifdef DEBUG_MMAP
   40:     printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
   41:            prot & PROT_READ ? 'r' : '-',
   42:            prot & PROT_WRITE ? 'w' : '-',
   43:            prot & PROT_EXEC ? 'x' : '-');
   44: #endif
   45: 
   46:     if ((start & ~TARGET_PAGE_MASK) != 0)
   47:         return -EINVAL;
   48:     len = TARGET_PAGE_ALIGN(len);
   49:     end = start + len;
   50:     if (end < start)
   51:         return -EINVAL;
   52:     if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
   53:         return -EINVAL;
   54:     if (len == 0)
   55:         return 0;
   56: 
   57:     host_start = start & qemu_host_page_mask;
   58:     host_end = HOST_PAGE_ALIGN(end);
   59:     if (start > host_start) {
   60:         /* handle host page containing start */
   61:         prot1 = prot;
   62:         for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
   63:             prot1 |= page_get_flags(addr);
   64:         }
   65:         if (host_end == host_start + qemu_host_page_size) {
   66:             for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
   67:                 prot1 |= page_get_flags(addr);
   68:             }
   69:             end = host_end;
   70:         }
   71:         ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
   72:         if (ret != 0)
   73:             return ret;
   74:         host_start += qemu_host_page_size;
   75:     }
   76:     if (end < host_end) {
   77:         prot1 = prot;
   78:         for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
   79:             prot1 |= page_get_flags(addr);
   80:         }
   81:         ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
   82:                        prot1 & PAGE_BITS);
   83:         if (ret != 0)
   84:             return ret;
   85:         host_end -= qemu_host_page_size;
   86:     }
   87: 
   88:     /* handle the pages in the middle */
   89:     if (host_start < host_end) {
   90:         ret = mprotect((void *)host_start, host_end - host_start, prot);
   91:         if (ret != 0)
   92:             return ret;
   93:     }
   94:     page_set_flags(start, start + len, prot | PAGE_VALID);
   95:     return 0;
   96: }
   97: 
   98: /* map an incomplete host page */
   99: int mmap_frag(unsigned long host_start,
  100:                unsigned long start, unsigned long end,
  101:                int prot, int flags, int fd, unsigned long offset)
  102: {
  103:     unsigned long host_end, ret, addr;
  104:     int prot1, prot_new;
  105: 
  106:     host_end = host_start + qemu_host_page_size;
  107: 
  108:     /* get the protection of the target pages outside the mapping */
  109:     prot1 = 0;
  110:     for(addr = host_start; addr < host_end; addr++) {
  111:         if (addr < start || addr >= end)
  112:             prot1 |= page_get_flags(addr);
  113:     }
  114: 
  115:     if (prot1 == 0) {
  116:         /* no page was there, so we allocate one */
  117:         ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
  118:                          flags | MAP_ANONYMOUS, -1, 0);
  119:         if (ret == -1)
  120:             return ret;
  121:     }
  122:     prot1 &= PAGE_BITS;
  123: 
  124:     prot_new = prot | prot1;
  125:     if (!(flags & MAP_ANONYMOUS)) {
  126:         /* msync() won't work here, so we return an error if write is
  127:            possible while it is a shared mapping */
  128: #ifndef __APPLE__
  129:         if ((flags & MAP_TYPE) == MAP_SHARED &&
  130: #else
  131:         if ((flags &  MAP_SHARED) &&
  132: #endif
  133:             (prot & PROT_WRITE))
  134:             return -EINVAL;
  135: 
  136:         /* adjust protection to be able to read */
  137:         if (!(prot1 & PROT_WRITE))
  138:             mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
  139: 
  140:         /* read the corresponding file data */
  141:         pread(fd, (void *)start, end - start, offset);
  142: 
  143:         /* put final protection */
  144:         if (prot_new != (prot1 | PROT_WRITE))
  145:             mprotect((void *)host_start, qemu_host_page_size, prot_new);
  146:     } else {
  147:         /* just update the protection */
  148:         if (prot_new != prot1) {
  149:             mprotect((void *)host_start, qemu_host_page_size, prot_new);
  150:         }
  151:     }
  152:     return 0;
  153: }
  154: 
  155: /* NOTE: all the constants are the HOST ones */
  156: long target_mmap(unsigned long start, unsigned long len, int prot,
  157:                  int flags, int fd, unsigned long offset)
  158: {
  159:     unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
  160: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
  161:     static unsigned long last_start = 0x40000000;
  162: #endif
  163: 
  164: #ifdef DEBUG_MMAP
  165:     {
  166:         printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
  167:                start, len,
  168:                prot & PROT_READ ? 'r' : '-',
  169:                prot & PROT_WRITE ? 'w' : '-',
  170:                prot & PROT_EXEC ? 'x' : '-');
  171:         if (flags & MAP_FIXED)
  172:             printf("MAP_FIXED ");
  173:         if (flags & MAP_ANONYMOUS)
  174:             printf("MAP_ANON ");
  175: #ifndef MAP_TYPE
  176: # define MAP_TYPE 0x3
  177: #endif
  178:         switch(flags & MAP_TYPE) {
  179:         case MAP_PRIVATE:
  180:             printf("MAP_PRIVATE ");
  181:             break;
  182:         case MAP_SHARED:
  183:             printf("MAP_SHARED ");
  184:             break;
  185:         default:
  186:             printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
  187:             break;
  188:         }
  189:         printf("fd=%d offset=%lx\n", fd, offset);
  190:     }
  191: #endif
  192: 
  193:     if (offset & ~TARGET_PAGE_MASK)
  194:         return -EINVAL;
  195: 
  196:     len = TARGET_PAGE_ALIGN(len);
  197:     if (len == 0)
  198:         return start;
  199:     host_start = start & qemu_host_page_mask;
  200: 
  201:     if (!(flags & MAP_FIXED)) {
  202: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
  203:         /* tell the kernel to search at the same place as i386 */
  204:         if (host_start == 0) {
  205:             host_start = last_start;
  206:             last_start += HOST_PAGE_ALIGN(len);
  207:         }
  208: #endif
  209:         if (qemu_host_page_size != qemu_real_host_page_size) {
  210:             /* NOTE: this code is only for debugging with '-p' option */
  211:             /* reserve a memory area */
  212:             host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
  213:             host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
  214:                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  215:             if (host_start == -1)
  216:                 return host_start;
  217:             host_end = host_start + host_len;
  218:             start = HOST_PAGE_ALIGN(host_start);
  219:             end = start + HOST_PAGE_ALIGN(len);
  220:             if (start > host_start)
  221:                 munmap((void *)host_start, start - host_start);
  222:             if (end < host_end)
  223:                 munmap((void *)end, host_end - end);
  224:             /* use it as a fixed mapping */
  225:             flags |= MAP_FIXED;
  226:         } else {
  227:             /* if not fixed, no need to do anything */
  228:             host_offset = offset & qemu_host_page_mask;
  229:             host_len = len + offset - host_offset;
  230:             start = (long)mmap((void *)host_start, host_len,
  231:                                prot, flags, fd, host_offset);
  232:             if (start == -1)
  233:                 return start;
  234:             /* update start so that it points to the file position at 'offset' */
  235:             if (!(flags & MAP_ANONYMOUS))
  236:                 start += offset - host_offset;
  237:             goto the_end1;
  238:         }
  239:     }
  240: 
  241:     if (start & ~TARGET_PAGE_MASK)
  242:         return -EINVAL;
  243:     end = start + len;
  244:     host_end = HOST_PAGE_ALIGN(end);
  245: 
  246:     /* worst case: we cannot map the file because the offset is not
  247:        aligned, so we read it */
  248:     if (!(flags & MAP_ANONYMOUS) &&
  249:         (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
  250:         /* msync() won't work here, so we return an error if write is
  251:            possible while it is a shared mapping */
  252: #ifndef __APPLE__
  253:         if ((flags & MAP_TYPE) == MAP_SHARED &&
  254: #else
  255:         if ((flags & MAP_SHARED) &&
  256: #endif
  257:             (prot & PROT_WRITE))
  258:             return -EINVAL;
  259:         retaddr = target_mmap(start, len, prot | PROT_WRITE,
  260:                               MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
  261:                               -1, 0);
  262:         if (retaddr == -1)
  263:             return retaddr;
  264:         pread(fd, (void *)start, len, offset);
  265:         if (!(prot & PROT_WRITE)) {
  266:             ret = target_mprotect(start, len, prot);
  267:             if (ret != 0)
  268:                 return ret;
  269:         }
  270:         goto the_end;
  271:     }
  272: 
  273:     /* handle the start of the mapping */
  274:     if (start > host_start) {
  275:         if (host_end == host_start + qemu_host_page_size) {
  276:             /* one single host page */
  277:             ret = mmap_frag(host_start, start, end,
  278:                             prot, flags, fd, offset);
  279:             if (ret == -1)
  280:                 return ret;
  281:             goto the_end1;
  282:         }
  283:         ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
  284:                         prot, flags, fd, offset);
  285:         if (ret == -1)
  286:             return ret;
  287:         host_start += qemu_host_page_size;
  288:     }
  289:     /* handle the end of the mapping */
  290:     if (end < host_end) {
  291:         ret = mmap_frag(host_end - qemu_host_page_size,
  292:                         host_end - qemu_host_page_size, host_end,
  293:                         prot, flags, fd,
  294:                         offset + host_end - qemu_host_page_size - start);
  295:         if (ret == -1)
  296:             return ret;
  297:         host_end -= qemu_host_page_size;
  298:     }
  299: 
  300:     /* map the middle (easier) */
  301:     if (host_start < host_end) {
  302:         unsigned long offset1;
  303: 	if (flags & MAP_ANONYMOUS)
  304: 	  offset1 = 0;
  305: 	else
  306: 	  offset1 = offset + host_start - start;
  307:         ret = (long)mmap((void *)host_start, host_end - host_start,
  308:                          prot, flags, fd, offset1);
  309:         if (ret == -1)
  310:             return ret;
  311:     }
  312:  the_end1:
  313:     page_set_flags(start, start + len, prot | PAGE_VALID);
  314:  the_end:
  315: #ifdef DEBUG_MMAP
  316:     printf("target_mmap: ret=0x%lx\n", (long)start);
  317:     page_dump(stdout);
  318:     printf("\n");
  319: #endif
  320:     return start;
  321: }
  322: 
  323: int target_munmap(unsigned long start, unsigned long len)
  324: {
  325:     unsigned long end, host_start, host_end, addr;
  326:     int prot, ret;
  327: 
  328: #ifdef DEBUG_MMAP
  329:     printf("munmap: start=0x%lx len=0x%lx\n", start, len);
  330: #endif
  331:     if (start & ~TARGET_PAGE_MASK)
  332:         return -EINVAL;
  333:     len = TARGET_PAGE_ALIGN(len);
  334:     if (len == 0)
  335:         return -EINVAL;
  336:     end = start + len;
  337:     host_start = start & qemu_host_page_mask;
  338:     host_end = HOST_PAGE_ALIGN(end);
  339: 
  340:     if (start > host_start) {
  341:         /* handle host page containing start */
  342:         prot = 0;
  343:         for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
  344:             prot |= page_get_flags(addr);
  345:         }
  346:         if (host_end == host_start + qemu_host_page_size) {
  347:             for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
  348:                 prot |= page_get_flags(addr);
  349:             }
  350:             end = host_end;
  351:         }
  352:         if (prot != 0)
  353:             host_start += qemu_host_page_size;
  354:     }
  355:     if (end < host_end) {
  356:         prot = 0;
  357:         for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
  358:             prot |= page_get_flags(addr);
  359:         }
  360:         if (prot != 0)
  361:             host_end -= qemu_host_page_size;
  362:     }
  363: 
  364:     /* unmap what we can */
  365:     if (host_start < host_end) {
  366:         ret = munmap((void *)host_start, host_end - host_start);
  367:         if (ret != 0)
  368:             return ret;
  369:     }
  370: 
  371:     page_set_flags(start, start + len, 0);
  372:     return 0;
  373: }
  374: 
  375: /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
  376:    blocks which have been allocated starting on a host page */
  377: long target_mremap(unsigned long old_addr, unsigned long old_size,
  378:                    unsigned long new_size, unsigned long flags,
  379:                    unsigned long new_addr)
  380: {
  381: #ifndef __APPLE__
  382:     /* XXX: use 5 args syscall */
  383:     new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
  384:     if (new_addr == -1)
  385:         return new_addr;
  386:     prot = page_get_flags(old_addr);
  387:     page_set_flags(old_addr, old_addr + old_size, 0);
  388:     page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
  389:     return new_addr;
  390: #else
  391:     qerror("target_mremap: unsupported\n");
  392: #endif
  393: 
  394: }
  395: 
  396: int target_msync(unsigned long start, unsigned long len, int flags)
  397: {
  398:     unsigned long end;
  399: 
  400:     if (start & ~TARGET_PAGE_MASK)
  401:         return -EINVAL;
  402:     len = TARGET_PAGE_ALIGN(len);
  403:     end = start + len;
  404:     if (end < start)
  405:         return -EINVAL;
  406:     if (end == start)
  407:         return 0;
  408: 
  409:     start &= qemu_host_page_mask;
  410:     return msync((void *)start, end - start, flags);
  411: }

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