]> wimlib.net Git - wimlib/blobdiff - src/win32.c
add_image => add
[wimlib] / src / win32.c
index 0fd7508a66b406d62981a1268176331872505113..f9f4276510c6b066bb0329592504dd359aa7eb5c 100644 (file)
@@ -48,6 +48,7 @@
 #define MAX_GET_SD_ACCESS_DENIED_WARNINGS 1
 #define MAX_GET_SACL_PRIV_NOTHELD_WARNINGS 1
 #define MAX_CREATE_HARD_LINK_WARNINGS 5
+#define MAX_CREATE_SOFT_LINK_WARNINGS 5
 struct win32_capture_state {
        unsigned long num_get_sd_access_denied;
        unsigned long num_get_sacl_priv_notheld;
@@ -78,6 +79,279 @@ win32_error(u32 err_code)
 #  define win32_error(err_code)
 #endif /* !ENABLE_ERROR_MESSAGES */
 
+static int
+win32_error_to_errno(DWORD err_code)
+{
+       /* This mapping is that used in Cygwin.
+        * Some of these choices are arbitrary. */
+       switch (err_code) {
+       case ERROR_ACCESS_DENIED:
+               return EACCES;
+       case ERROR_ACTIVE_CONNECTIONS:
+               return EAGAIN;
+       case ERROR_ALREADY_EXISTS:
+               return EEXIST;
+       case ERROR_BAD_DEVICE:
+               return ENODEV;
+       case ERROR_BAD_EXE_FORMAT:
+               return ENOEXEC;
+       case ERROR_BAD_NETPATH:
+               return ENOENT;
+       case ERROR_BAD_NET_NAME:
+               return ENOENT;
+       case ERROR_BAD_NET_RESP:
+               return ENOSYS;
+       case ERROR_BAD_PATHNAME:
+               return ENOENT;
+       case ERROR_BAD_PIPE:
+               return EINVAL;
+       case ERROR_BAD_UNIT:
+               return ENODEV;
+       case ERROR_BAD_USERNAME:
+               return EINVAL;
+       case ERROR_BEGINNING_OF_MEDIA:
+               return EIO;
+       case ERROR_BROKEN_PIPE:
+               return EPIPE;
+       case ERROR_BUSY:
+               return EBUSY;
+       case ERROR_BUS_RESET:
+               return EIO;
+       case ERROR_CALL_NOT_IMPLEMENTED:
+               return ENOSYS;
+       case ERROR_CANNOT_MAKE:
+               return EPERM;
+       case ERROR_CHILD_NOT_COMPLETE:
+               return EBUSY;
+       case ERROR_COMMITMENT_LIMIT:
+               return EAGAIN;
+       case ERROR_CRC:
+               return EIO;
+       case ERROR_DEVICE_DOOR_OPEN:
+               return EIO;
+       case ERROR_DEVICE_IN_USE:
+               return EAGAIN;
+       case ERROR_DEVICE_REQUIRES_CLEANING:
+               return EIO;
+       case ERROR_DIRECTORY:
+               return ENOTDIR;
+       case ERROR_DIR_NOT_EMPTY:
+               return ENOTEMPTY;
+       case ERROR_DISK_CORRUPT:
+               return EIO;
+       case ERROR_DISK_FULL:
+               return ENOSPC;
+#ifdef ENOTUNIQ
+       case ERROR_DUP_NAME:
+               return ENOTUNIQ;
+#endif
+       case ERROR_EAS_DIDNT_FIT:
+               return ENOSPC;
+       case ERROR_EAS_NOT_SUPPORTED:
+               return ENOTSUP;
+       case ERROR_EA_LIST_INCONSISTENT:
+               return EINVAL;
+       case ERROR_EA_TABLE_FULL:
+               return ENOSPC;
+       case ERROR_END_OF_MEDIA:
+               return ENOSPC;
+       case ERROR_EOM_OVERFLOW:
+               return EIO;
+       case ERROR_EXE_MACHINE_TYPE_MISMATCH:
+               return ENOEXEC;
+       case ERROR_EXE_MARKED_INVALID:
+               return ENOEXEC;
+       case ERROR_FILEMARK_DETECTED:
+               return EIO;
+       case ERROR_FILENAME_EXCED_RANGE:
+               return ENAMETOOLONG;
+       case ERROR_FILE_CORRUPT:
+               return EEXIST;
+       case ERROR_FILE_EXISTS:
+               return EEXIST;
+       case ERROR_FILE_INVALID:
+               return ENXIO;
+       case ERROR_FILE_NOT_FOUND:
+               return ENOENT;
+       case ERROR_HANDLE_DISK_FULL:
+               return ENOSPC;
+#ifdef ENODATA
+       case ERROR_HANDLE_EOF:
+               return ENODATA;
+#endif
+       case ERROR_INVALID_ADDRESS:
+               return EINVAL;
+       case ERROR_INVALID_AT_INTERRUPT_TIME:
+               return EINTR;
+       case ERROR_INVALID_BLOCK_LENGTH:
+               return EIO;
+       case ERROR_INVALID_DATA:
+               return EINVAL;
+       case ERROR_INVALID_DRIVE:
+               return ENODEV;
+       case ERROR_INVALID_EA_NAME:
+               return EINVAL;
+       case ERROR_INVALID_EXE_SIGNATURE:
+               return ENOEXEC;
+#ifdef EBADRQC
+       case ERROR_INVALID_FUNCTION:
+               return EBADRQC;
+#endif
+       case ERROR_INVALID_HANDLE:
+               return EBADF;
+       case ERROR_INVALID_NAME:
+               return ENOENT;
+       case ERROR_INVALID_PARAMETER:
+               return EINVAL;
+       case ERROR_INVALID_SIGNAL_NUMBER:
+               return EINVAL;
+       case ERROR_IOPL_NOT_ENABLED:
+               return ENOEXEC;
+       case ERROR_IO_DEVICE:
+               return EIO;
+       case ERROR_IO_INCOMPLETE:
+               return EAGAIN;
+       case ERROR_IO_PENDING:
+               return EAGAIN;
+       case ERROR_LOCK_VIOLATION:
+               return EBUSY;
+       case ERROR_MAX_THRDS_REACHED:
+               return EAGAIN;
+       case ERROR_META_EXPANSION_TOO_LONG:
+               return EINVAL;
+       case ERROR_MOD_NOT_FOUND:
+               return ENOENT;
+#ifdef EMSGSIZE
+       case ERROR_MORE_DATA:
+               return EMSGSIZE;
+#endif
+       case ERROR_NEGATIVE_SEEK:
+               return EINVAL;
+       case ERROR_NETNAME_DELETED:
+               return ENOENT;
+       case ERROR_NOACCESS:
+               return EFAULT;
+       case ERROR_NONE_MAPPED:
+               return EINVAL;
+       case ERROR_NONPAGED_SYSTEM_RESOURCES:
+               return EAGAIN;
+#ifdef ENOLINK
+       case ERROR_NOT_CONNECTED:
+               return ENOLINK;
+#endif
+       case ERROR_NOT_ENOUGH_MEMORY:
+               return ENOMEM;
+       case ERROR_NOT_OWNER:
+               return EPERM;
+#ifdef ENOMEDIUM
+       case ERROR_NOT_READY:
+               return ENOMEDIUM;
+#endif
+       case ERROR_NOT_SAME_DEVICE:
+               return EXDEV;
+       case ERROR_NOT_SUPPORTED:
+               return ENOSYS;
+       case ERROR_NO_DATA:
+               return EPIPE;
+       case ERROR_NO_DATA_DETECTED:
+               return EIO;
+#ifdef ENOMEDIUM
+       case ERROR_NO_MEDIA_IN_DRIVE:
+               return ENOMEDIUM;
+#endif
+#ifdef ENMFILE
+       case ERROR_NO_MORE_FILES:
+               return ENMFILE;
+#endif
+#ifdef ENMFILE
+       case ERROR_NO_MORE_ITEMS:
+               return ENMFILE;
+#endif
+       case ERROR_NO_MORE_SEARCH_HANDLES:
+               return ENFILE;
+       case ERROR_NO_PROC_SLOTS:
+               return EAGAIN;
+       case ERROR_NO_SIGNAL_SENT:
+               return EIO;
+       case ERROR_NO_SYSTEM_RESOURCES:
+               return EFBIG;
+       case ERROR_NO_TOKEN:
+               return EINVAL;
+       case ERROR_OPEN_FAILED:
+               return EIO;
+       case ERROR_OPEN_FILES:
+               return EAGAIN;
+       case ERROR_OUTOFMEMORY:
+               return ENOMEM;
+       case ERROR_PAGED_SYSTEM_RESOURCES:
+               return EAGAIN;
+       case ERROR_PAGEFILE_QUOTA:
+               return EAGAIN;
+       case ERROR_PATH_NOT_FOUND:
+               return ENOENT;
+       case ERROR_PIPE_BUSY:
+               return EBUSY;
+       case ERROR_PIPE_CONNECTED:
+               return EBUSY;
+#ifdef ECOMM
+       case ERROR_PIPE_LISTENING:
+               return ECOMM;
+       case ERROR_PIPE_NOT_CONNECTED:
+               return ECOMM;
+#endif
+       case ERROR_POSSIBLE_DEADLOCK:
+               return EDEADLOCK;
+       case ERROR_PRIVILEGE_NOT_HELD:
+               return EPERM;
+       case ERROR_PROCESS_ABORTED:
+               return EFAULT;
+       case ERROR_PROC_NOT_FOUND:
+               return ESRCH;
+#ifdef ENONET
+       case ERROR_REM_NOT_LIST:
+               return ENONET;
+#endif
+       case ERROR_SECTOR_NOT_FOUND:
+               return EINVAL;
+       case ERROR_SEEK:
+               return EINVAL;
+       case ERROR_SETMARK_DETECTED:
+               return EIO;
+       case ERROR_SHARING_BUFFER_EXCEEDED:
+               return ENOLCK;
+       case ERROR_SHARING_VIOLATION:
+               return EBUSY;
+       case ERROR_SIGNAL_PENDING:
+               return EBUSY;
+       case ERROR_SIGNAL_REFUSED:
+               return EIO;
+#ifdef ELIBBAD
+       case ERROR_SXS_CANT_GEN_ACTCTX:
+               return ELIBBAD;
+#endif
+       case ERROR_THREAD_1_INACTIVE:
+               return EINVAL;
+       case ERROR_TOO_MANY_LINKS:
+               return EMLINK;
+       case ERROR_TOO_MANY_OPEN_FILES:
+               return EMFILE;
+       case ERROR_WAIT_NO_CHILDREN:
+               return ECHILD;
+       case ERROR_WORKING_SET_QUOTA:
+               return EAGAIN;
+       case ERROR_WRITE_PROTECT:
+               return EROFS;
+       default:
+               return -1;
+       }
+}
+
+static void
+set_errno_from_GetLastError()
+{
+       errno = win32_error_to_errno(GetLastError());
+}
+
 /* Pointers to functions that are not available on all targetted versions of
  * Windows (XP and later).  NOTE: The WINAPI annotations seem to be important; I
  * assume it specifies a certain calling convention. */
@@ -428,7 +702,7 @@ win32_get_security_descriptor(struct wim_dentry *dentry,
                              struct sd_set *sd_set,
                              const wchar_t *path,
                              struct win32_capture_state *state,
-                             int add_image_flags)
+                             int add_flags)
 {
        SECURITY_INFORMATION requestedInformation;
        DWORD lenNeeded = 0;
@@ -463,7 +737,7 @@ again:
                }
        }
 
-       if (add_image_flags & WIMLIB_ADD_IMAGE_FLAG_STRICT_ACLS)
+       if (add_flags & WIMLIB_ADD_FLAG_STRICT_ACLS)
                goto fail;
 
        switch (err) {
@@ -653,7 +927,7 @@ enum rp_status {
  * fixup where we change it to be absolute relative to the root of the directory
  * tree being captured.
  *
- * Note that this is only executed when WIMLIB_ADD_IMAGE_FLAG_RPFIX has been
+ * Note that this is only executed when WIMLIB_ADD_FLAG_RPFIX has been
  * set.
  *
  * @capture_root_ino and @capture_root_dev indicate the inode number and device
@@ -739,7 +1013,7 @@ win32_capture_try_rpfix(u8 *rpbuf, u16 *rpbuflen_p,
                else
                        ret = -ret;
        } else {
-               if (ret == RP_EXCLUDED) {
+               if (rp_status == RP_EXCLUDED) {
                        size_t print_name_nchars = rpdata.print_name_nbytes / 2;
                        wchar_t print_name0[print_name_nchars + 1];
                        print_name0[print_name_nchars] = L'\0';
@@ -811,7 +1085,7 @@ win32_get_reparse_data(HANDLE hFile, const wchar_t *path,
 
        rpbuflen = bytesReturned;
        reparse_tag = le32_to_cpu(*(u32*)rpbuf);
-       if (params->add_image_flags & WIMLIB_ADD_IMAGE_FLAG_RPFIX &&
+       if (params->add_flags & WIMLIB_ADD_FLAG_RPFIX &&
            (reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
             reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT))
        {
@@ -1131,12 +1405,12 @@ win32_build_dentry_tree_recursive(struct wim_dentry **root_ret,
        u16 not_rpfixed;
 
        if (exclude_path(path, path_num_chars, params->config, true)) {
-               if (params->add_image_flags & WIMLIB_ADD_IMAGE_FLAG_ROOT) {
+               if (params->add_flags & WIMLIB_ADD_FLAG_ROOT) {
                        ERROR("Cannot exclude the root directory from capture");
                        ret = WIMLIB_ERR_INVALID_CAPTURE_CONFIG;
                        goto out;
                }
-               if ((params->add_image_flags & WIMLIB_ADD_IMAGE_FLAG_EXCLUDE_VERBOSE)
+               if ((params->add_flags & WIMLIB_ADD_FLAG_EXCLUDE_VERBOSE)
                    && params->progress_func)
                {
                        union wimlib_progress_info info;
@@ -1148,7 +1422,7 @@ win32_build_dentry_tree_recursive(struct wim_dentry **root_ret,
                goto out;
        }
 
-       if ((params->add_image_flags & WIMLIB_ADD_IMAGE_FLAG_VERBOSE)
+       if ((params->add_flags & WIMLIB_ADD_FLAG_VERBOSE)
            && params->progress_func)
        {
                union wimlib_progress_info info;
@@ -1227,14 +1501,14 @@ win32_build_dentry_tree_recursive(struct wim_dentry **root_ret,
        inode->i_last_access_time = FILETIME_to_u64(&file_info.ftLastAccessTime);
        inode->i_resolved = 1;
 
-       params->add_image_flags &= ~(WIMLIB_ADD_IMAGE_FLAG_ROOT | WIMLIB_ADD_IMAGE_FLAG_SOURCE);
+       params->add_flags &= ~WIMLIB_ADD_FLAG_ROOT;
 
-       if (!(params->add_image_flags & WIMLIB_ADD_IMAGE_FLAG_NO_ACLS)
+       if (!(params->add_flags & WIMLIB_ADD_FLAG_NO_ACLS)
            && (vol_flags & FILE_PERSISTENT_ACLS))
        {
                ret = win32_get_security_descriptor(root, params->sd_set,
                                                    path, state,
-                                                   params->add_image_flags);
+                                                   params->add_flags);
                if (ret)
                        goto out_close_handle;
        }
@@ -1284,7 +1558,7 @@ out:
 
 static void
 win32_do_capture_warnings(const struct win32_capture_state *state,
-                         int add_image_flags)
+                         int add_flags)
 {
        if (state->num_get_sacl_priv_notheld == 0 &&
            state->num_get_sd_access_denied == 0)
@@ -1307,7 +1581,7 @@ win32_do_capture_warnings(const struct win32_capture_state *state,
 "          desired metadata has been captured exactly.  However, if you\n"
 "          do not care about capturing security descriptors correctly, then\n"
 "          nothing more needs to be done%ls\n",
-       (add_image_flags & WIMLIB_ADD_IMAGE_FLAG_NO_ACLS) ? L"." :
+       (add_flags & WIMLIB_ADD_FLAG_NO_ACLS) ? L"." :
          L", although you might consider\n"
 "          passing the --no-acls flag to `wimlib-imagex capture' or\n"
 "          `wimlib-imagex append' to explicitly capture no security\n"
@@ -1363,7 +1637,7 @@ win32_build_dentry_tree(struct wim_dentry **root_ret,
                                                &state, vol_flags);
        FREE(path);
        if (ret == 0)
-               win32_do_capture_warnings(&state, params->add_image_flags);
+               win32_do_capture_warnings(&state, params->add_flags);
        return ret;
 }
 
@@ -1460,7 +1734,7 @@ win32_set_reparse_data(HANDLE h,
                       const struct wim_inode *inode,
                       const struct wim_lookup_table_entry *lte,
                       const wchar_t *path,
-                      const struct apply_args *args)
+                      struct apply_args *args)
 {
        int ret;
        u8 rpbuf[REPARSE_POINT_MAX_SIZE];
@@ -1512,15 +1786,30 @@ win32_set_reparse_data(HANDLE h,
                             NULL /* lpOverlapped */))
        {
                DWORD err = GetLastError();
-               ERROR("Failed to set reparse data on \"%ls\"", path);
-               win32_error(err);
                if (err == ERROR_ACCESS_DENIED || err == ERROR_PRIVILEGE_NOT_HELD)
-                       return WIMLIB_ERR_INSUFFICIENT_PRIVILEGES_TO_EXTRACT;
-               else if (inode->i_reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
-                        inode->i_reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT)
-                       return WIMLIB_ERR_LINK;
-               else
-                       return WIMLIB_ERR_WRITE;
+               {
+                       args->num_soft_links_failed++;
+                       if (args->num_soft_links_failed <= MAX_CREATE_SOFT_LINK_WARNINGS) {
+                               WARNING("Can't set reparse data on \"%ls\": Access denied!\n"
+                                       "          You may be trying to extract a symbolic "
+                                       "link without the\n"
+                                       "          SeCreateSymbolicLink privilege, which by "
+                                       "default non-Administrator\n"
+                                       "          accounts do not have.", path);
+                       }
+                       if (args->num_hard_links_failed == MAX_CREATE_HARD_LINK_WARNINGS) {
+                               WARNING("Suppressing further warnings regarding failure to extract\n"
+                                       "          reparse points due to insufficient privileges...");
+                       }
+               } else {
+                       ERROR("Failed to set reparse data on \"%ls\"", path);
+                       win32_error(err);
+                       if (inode->i_reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
+                           inode->i_reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT)
+                               return WIMLIB_ERR_LINK;
+                       else
+                               return WIMLIB_ERR_WRITE;
+               }
        }
        return 0;
 }
@@ -1724,7 +2013,7 @@ win32_encrypted_import_cb(unsigned char *data, void *_ctx,
 
        len = min(len, wim_resource_size(lte) - ctx->offset);
 
-       if (read_partial_wim_resource_into_buf(lte, len, ctx->offset, data, false))
+       if (read_partial_wim_resource_into_buf(lte, len, ctx->offset, data))
                return ERROR_READ_FAULT;
 
        ctx->offset += len;
@@ -2328,7 +2617,7 @@ win32_extract_streams(const struct wim_dentry *dentry,
                        continue;
 
                /* Skip special UNIX data entries (see documentation for
-                * WIMLIB_ADD_IMAGE_FLAG_UNIX_DATA) */
+                * WIMLIB_ADD_FLAG_UNIX_DATA) */
                if (ads_entry->stream_name_nbytes == WIMLIB_UNIX_DATA_TAG_UTF16LE_NBYTES
                    && !memcmp(ads_entry->stream_name,
                               WIMLIB_UNIX_DATA_TAG_UTF16LE,
@@ -2435,12 +2724,13 @@ win32_try_hard_link(const wchar_t *output_path, const struct wim_inode *inode,
                return WIMLIB_ERR_LINK;
        } else {
                args->num_hard_links_failed++;
-               if (args->num_hard_links_failed < MAX_CREATE_HARD_LINK_WARNINGS) {
+               if (args->num_hard_links_failed <= MAX_CREATE_HARD_LINK_WARNINGS) {
                        WARNING("Can't create hard link \"%ls => %ls\":\n"
                                "          Volume does not support hard links!\n"
                                "          Falling back to extracting a copy of the file.",
                                output_path, inode->i_extracted_file);
-               } else if (args->num_hard_links_failed == MAX_CREATE_HARD_LINK_WARNINGS) {
+               }
+               if (args->num_hard_links_failed == MAX_CREATE_HARD_LINK_WARNINGS) {
                        WARNING("Suppressing further hard linking warnings...");
                }
                return -1;
@@ -2515,8 +2805,8 @@ win32_do_apply_dentry(const wchar_t *output_path,
 int
 win32_do_apply_dentry_timestamps(const wchar_t *path,
                                 size_t path_num_chars,
-                                const struct wim_dentry *dentry,
-                                const struct apply_args *args)
+                                struct wim_dentry *dentry,
+                                struct apply_args *args)
 {
        DWORD err;
        HANDLE h;
@@ -2573,25 +2863,18 @@ out:
 int
 fsync(int fd)
 {
-       DWORD err;
        HANDLE h;
 
        h = (HANDLE)_get_osfhandle(fd);
-       if (h == INVALID_HANDLE_VALUE) {
-               err = GetLastError();
-               ERROR("Could not get Windows handle for file descriptor");
-               win32_error(err);
-               errno = EBADF;
-               return -1;
-       }
-       if (!FlushFileBuffers(h)) {
-               err = GetLastError();
-               ERROR("Could not flush file buffers to disk");
-               win32_error(err);
-               errno = EIO;
-               return -1;
-       }
+       if (h == INVALID_HANDLE_VALUE)
+               goto err;
+       if (!FlushFileBuffers(h))
+               goto err_set_errno;
        return 0;
+err_set_errno:
+       set_errno_from_GetLastError();
+err:
+       return -1;
 }
 
 /* Use the Win32 API to get the number of processors */
@@ -2610,8 +2893,8 @@ wchar_t *
 realpath(const wchar_t *path, wchar_t *resolved_path)
 {
        DWORD ret;
-       wimlib_assert(resolved_path == NULL);
        DWORD err;
+       wimlib_assert(resolved_path == NULL);
 
        ret = GetFullPathNameW(path, 0, NULL, NULL);
        if (!ret) {
@@ -2631,8 +2914,7 @@ realpath(const wchar_t *path, wchar_t *resolved_path)
        }
        goto out;
 fail_win32:
-       win32_error(err);
-       errno = -1;
+       errno = win32_error_to_errno(err);
 out:
        return resolved_path;
 }
@@ -2645,12 +2927,7 @@ win32_rename_replacement(const wchar_t *oldpath, const wchar_t *newpath)
        if (MoveFileExW(oldpath, newpath, MOVEFILE_REPLACE_EXISTING)) {
                return 0;
        } else {
-               /* As usual, the possible error values are not documented */
-               DWORD err = GetLastError();
-               ERROR("MoveFileEx(): Can't rename \"%ls\" to \"%ls\"",
-                     oldpath, newpath);
-               win32_error(err);
-               errno = -1;
+               set_errno_from_GetLastError();
                return -1;
        }
 }
@@ -2691,9 +2968,7 @@ fail_close_handle:
 fail:
        if (err == NO_ERROR)
                err = GetLastError();
-       ERROR("Can't truncate \"%ls\" to %"PRIu64" bytes", path, size);
-       win32_error(err);
-       errno = -1;
+       errno = win32_error_to_errno(err);
        return -1;
 }
 
@@ -2713,4 +2988,93 @@ win32_strerror_r_replacement(int errnum, wchar_t *buf, size_t buflen)
        return 0;
 }
 
+static int
+do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
+                  bool is_pwrite)
+{
+       HANDLE h;
+       LARGE_INTEGER orig_offset;
+       DWORD bytes_read_or_written;
+       LARGE_INTEGER relative_offset;
+       OVERLAPPED overlapped;
+       BOOL bret;
+
+       wimlib_assert(count <= 0xffffffff);
+
+       h = (HANDLE)_get_osfhandle(fd);
+       if (h == INVALID_HANDLE_VALUE)
+               goto err;
+
+       /* Get original position */
+       relative_offset.QuadPart = 0;
+       if (!SetFilePointerEx(h, relative_offset, &orig_offset, FILE_CURRENT))
+               goto err_set_errno;
+
+       memset(&overlapped, 0, sizeof(overlapped));
+       overlapped.Offset = offset;
+       overlapped.OffsetHigh = offset >> 32;
+
+       /* Do the read or write at the specified offset */
+       if (is_pwrite)
+               bret = WriteFile(h, buf, count, &bytes_read_or_written, &overlapped);
+       else
+               bret = ReadFile(h, buf, count, &bytes_read_or_written, &overlapped);
+       if (!bret)
+               goto err_set_errno;
+
+       /* Restore the original position */
+       if (!SetFilePointerEx(h, orig_offset, NULL, FILE_BEGIN))
+               goto err_set_errno;
+
+       return bytes_read_or_written;
+err_set_errno:
+       set_errno_from_GetLastError();
+err:
+       return -1;
+}
+
+/* Dumb Windows implementation of pread().  It temporarily changes the file
+ * offset, so it is not safe to use with readers/writers on the same file
+ * descriptor.  */
+extern ssize_t
+win32_pread(int fd, void *buf, size_t count, off_t offset)
+{
+       return do_pread_or_pwrite(fd, buf, count, offset, false);
+}
+
+/* Dumb Windows implementation of pwrite().  It temporarily changes the file
+ * offset, so it is not safe to use with readers/writers on the same file
+ * descriptor. */
+extern ssize_t
+win32_pwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+       return do_pread_or_pwrite(fd, (void*)buf, count, offset, true);
+}
+
+/* Dumb Windows implementation of writev().  It writes the vectors one at a
+ * time. */
+extern ssize_t
+win32_writev(int fd, const struct iovec *iov, int iovcnt)
+{
+       ssize_t total_bytes_written = 0;
+
+       if (iovcnt <= 0) {
+               errno = EINVAL;
+               return -1;
+       }
+       for (int i = 0; i < iovcnt; i++) {
+               ssize_t bytes_written;
+
+               bytes_written = write(fd, iov[i].iov_base, iov[i].iov_len);
+               if (bytes_written >= 0)
+                       total_bytes_written += bytes_written;
+               if (bytes_written != iov[i].iov_len) {
+                       if (total_bytes_written == 0)
+                               total_bytes_written = -1;
+                       break;
+               }
+       }
+       return total_bytes_written;
+}
+
 #endif /* __WIN32__ */