src/compat/mman.c

   1 /*
   2  * compat/compat_mman.h
   3  *
   4  * Copyright (C) 2013   JP Ikaheimonen <jp_ikaheimonen@mentor.com>
   5  *               2016   Michael Jeanson <mjeanson@efficios.com>
   6  *
   7  * These sources are based on ftp://g.oswego.edu/pub/misc/malloc.c
   8  * file by Doug Lea, released to the public domain.
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26  * SOFTWARE.
  27  */
  28
  29 #define BT_LOG_TAG "COMPAT-MMAN"
  30 #include "logging.h"
  31
  32 #ifdef __APPLE__
  33 /*
  34  * On macOS, we need a dummy symbol so that the linker won't
  35  * complain of an empty table of contents.
  36  */
  37 BT_HIDDEN
  38 int bt_mman_dummy_symbol;
  39 #endif /* __APPLE__ */
  40
  41 #ifdef __MINGW32__
  42
  43 #include <errno.h>
  44 #include <io.h>
  45 #include <pthread.h>
  46 #include <stdlib.h>
  47 #include <windows.h>
  48 #include "compat/mman.h"
  49
  50 struct mmap_mapping {
  51         /* The duplicated handle. */
  52         HANDLE file_handle;
  53         /* Handle returned by CreateFileMapping. */
  54         HANDLE map_handle;
  55 };
  56
  57 static
  58 GHashTable *mmap_mappings = NULL;
  59
  60 /*
  61  * This mutex protects the hashtable of memory mappings.
  62  */
  63 static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
  64
  65 static
  66 struct mmap_mapping *mapping_create(void)
  67 {
  68         struct mmap_mapping *mapping;
  69
  70         mapping = malloc(sizeof(struct mmap_mapping));
  71         if (mapping != NULL) {
  72                 mapping->file_handle = NULL;
  73                 mapping->map_handle = NULL;
  74         }
  75
  76         return mapping;
  77 }
  78
  79 static
  80 void mapping_clean(struct mmap_mapping *mapping)
  81 {
  82         if (mapping) {
  83                 if (!CloseHandle(mapping->map_handle)) {
  84                         BT_LOGF_STR("Failed to close mmap map_handle.");
  85                         abort();
  86                 }
  87                 if (!CloseHandle(mapping->file_handle)) {
  88                         BT_LOGF_STR("Failed to close mmap file_handle.");
  89                         abort();
  90                 }
  91                 free(mapping);
  92                 mapping = NULL;
  93         }
  94 }
  95
  96 static
  97 void addr_clean(void *addr)
  98 {
  99         /* Cleanup of handles should never fail. */
 100         if (!UnmapViewOfFile(addr)) {
 101                 BT_LOGF_STR("Failed to unmap mmap mapping.");
 102                 abort();
 103         }
 104 }
 105
 106 static
 107 void mmap_lock(void)
 108 {
 109         if (pthread_mutex_lock(&mmap_mutex)) {
 110                 BT_LOGF_STR("Failed to acquire mmap_mutex.");
 111                 abort();
 112         }
 113 }
 114
 115 static
 116 void mmap_unlock(void)
 117 {
 118         if (pthread_mutex_unlock(&mmap_mutex)) {
 119                 BT_LOGF_STR("Failed to release mmap_mutex.");
 120                 abort();
 121         }
 122 }
 123
 124 /*
 125  * Convert mmap memory protection flags to CreateFileMapping page protection
 126  * flag and MapViewOfFile desired access flag.
 127  */
 128 static
 129 DWORD map_prot_flags(int prot, DWORD *dwDesiredAccess)
 130 {
 131         if (prot & PROT_READ) {
 132                 if (prot & PROT_WRITE) {
 133                         *dwDesiredAccess = FILE_MAP_WRITE;
 134                         if (prot & PROT_EXEC) {
 135                                 return PAGE_EXECUTE_READWRITE;
 136                         }
 137                         return PAGE_READWRITE;
 138                 }
 139                 if (prot & PROT_EXEC) {
 140                         *dwDesiredAccess = FILE_MAP_EXECUTE;
 141                         return PAGE_EXECUTE_READ;
 142                 }
 143                 *dwDesiredAccess = FILE_MAP_READ;
 144                 return PAGE_READONLY;
 145         }
 146         if (prot & PROT_WRITE) {
 147                 *dwDesiredAccess = FILE_MAP_COPY;
 148                 return PAGE_WRITECOPY;
 149         }
 150         if (prot & PROT_EXEC) {
 151                 *dwDesiredAccess = FILE_MAP_EXECUTE;
 152                 return PAGE_EXECUTE_READ;
 153         }
 154
 155         /* Mapping failed. */
 156         *dwDesiredAccess = 0;
 157         return 0;
 158 }
 159
 160 BT_HIDDEN
 161 void *bt_mmap(void *addr, size_t length, int prot, int flags, int fd,
 162                 off_t offset)
 163 {
 164         struct mmap_mapping *mapping = NULL;
 165         void *mapping_addr;
 166         DWORD dwDesiredAccess;
 167         DWORD flProtect;
 168         HANDLE handle;
 169
 170         /* Check for a valid fd. */
 171         if (fd == -1) {
 172                 _set_errno(EBADF);
 173                 goto error;
 174         }
 175
 176         /* We don't support this at the moment. */
 177         if (flags == MAP_FIXED) {
 178                 _set_errno(ENOTSUP);
 179                 goto error;
 180         }
 181
 182         /* Map mmap flags to those of the Windows API. */
 183         flProtect = map_prot_flags(prot, &dwDesiredAccess);
 184         if (flProtect == 0) {
 185                 _set_errno(EINVAL);
 186                 goto error;
 187         }
 188
 189         /* Allocate the mapping struct. */
 190         mapping = mapping_create();
 191         if (!mapping) {
 192                 BT_LOGE_STR("Failed to allocate mmap mapping.");
 193                 _set_errno(ENOMEM);
 194                 goto error;
 195         }
 196
 197         /* Get a handle from the fd. */
 198         handle = (HANDLE) _get_osfhandle(fd);
 199
 200         /* Duplicate the handle and store it in 'mapping.file_handle'. */
 201         if (!DuplicateHandle(GetCurrentProcess(), handle, GetCurrentProcess(),
 202                         &mapping->file_handle, 0, FALSE,
 203                         DUPLICATE_SAME_ACCESS)) {
 204                 _set_errno(ENOMEM);
 205                 goto error;
 206         }
 207
 208         /*
 209          * Create a file mapping object with a maximum size
 210          * of 'offset' + 'length'.
 211          */
 212         mapping->map_handle = CreateFileMapping(mapping->file_handle, NULL,
 213                         flProtect, 0, offset + length, NULL);
 214         if (mapping->map_handle == 0) {
 215                 _set_errno(EACCES);
 216                 goto error;
 217         }
 218
 219         /* Map the requested block starting at 'offset' for 'length' bytes. */
 220         mapping_addr = MapViewOfFile(mapping->map_handle, dwDesiredAccess, 0,
 221                         offset, length);
 222         if (mapping_addr == 0) {
 223                 DWORD dwLastErr = GetLastError();
 224                 if (dwLastErr == ERROR_MAPPED_ALIGNMENT) {
 225                         _set_errno(EINVAL);
 226                 } else {
 227                         _set_errno(EACCES);
 228                 }
 229                 goto error;
 230         }
 231
 232         mmap_lock();
 233
 234         /* If we have never done any mappings, allocate the hashtable. */
 235         if (!mmap_mappings) {
 236                 mmap_mappings = g_hash_table_new_full(g_direct_hash,
 237                         g_direct_equal, (GDestroyNotify) addr_clean,
 238                         (GDestroyNotify) mapping_clean);
 239                 if (!mmap_mappings) {
 240                         BT_LOGE_STR("Failed to allocate mmap hashtable.");
 241                         _set_errno(ENOMEM);
 242                         goto error_mutex_unlock;
 243                 }
 244         }
 245
 246         /* Add the new mapping to the hashtable. */
 247         g_hash_table_insert(mmap_mappings, mapping_addr, mapping);
 248
 249         mmap_unlock();
 250
 251         return mapping_addr;
 252
 253 error_mutex_unlock:
 254         mmap_unlock();
 255 error:
 256         mapping_clean(mapping);
 257         return MAP_FAILED;
 258 }
 259
 260 BT_HIDDEN
 261 int bt_munmap(void *addr, size_t length)
 262 {
 263         int ret = 0;
 264
 265         mmap_lock();
 266
 267         /* Check if the mapping exists in the hashtable. */
 268         if (g_hash_table_lookup(mmap_mappings, addr) == NULL) {
 269                 _set_errno(EINVAL);
 270                 ret = -1;
 271                 goto end;
 272         }
 273
 274         /* Remove it. */
 275         if (!g_hash_table_remove(mmap_mappings, addr)) {
 276                 BT_LOGF_STR("Failed to remove mapping from hashtable.");
 277                 abort();
 278         }
 279
 280 end:
 281         mmap_unlock();
 282         return ret;
 283 }
 284
 285 #endif