synthetic_file.c

 
#include <winpr/config.h>
#include <winpr/platform.h>
 
WINPR_PRAGMA_DIAG_PUSH
WINPR_PRAGMA_DIAG_IGNORED_RESERVED_ID_MACRO
WINPR_PRAGMA_DIAG_IGNORED_UNUSED_MACRO
 
#define _FILE_OFFSET_BITS 64 // NOLINT(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp)
 
WINPR_PRAGMA_DIAG_POP
 
#include <errno.h>
 
#include <winpr/wtypes.h>
 
#include <winpr/crt.h>
#include <winpr/clipboard.h>
#include <winpr/collections.h>
#include <winpr/file.h>
#include <winpr/shell.h>
#include <winpr/string.h>
#include <winpr/wlog.h>
#include <winpr/path.h>
#include <winpr/print.h>
 
#include "clipboard.h"
#include "synthetic_file.h"
 
#include "../log.h"
#define TAG WINPR_TAG("clipboard.synthetic.file")
 
static const char* mime_uri_list = "text/uri-list";
static const char* mime_FileGroupDescriptorW = "FileGroupDescriptorW";
static const char* mime_gnome_copied_files = "x-special/gnome-copied-files";
static const char* mime_mate_copied_files = "x-special/mate-copied-files";
 
struct synthetic_file
{
  WCHAR* local_name;
  WCHAR* remote_name;
 
  HANDLE fd;
  INT64 offset;
 
  DWORD dwFileAttributes;
  FILETIME ftCreationTime;
  FILETIME ftLastAccessTime;
  FILETIME ftLastWriteTime;
  DWORD nFileSizeHigh;
  DWORD nFileSizeLow;
};
 
void free_synthetic_file(struct synthetic_file* file);
 
static struct synthetic_file* make_synthetic_file(const WCHAR* local_name, const WCHAR* remote_name)
{
  struct synthetic_file* file = NULL;
  WIN32_FIND_DATAW fd = { 0 };
  HANDLE hFind = NULL;
 
  WINPR_ASSERT(local_name);
  WINPR_ASSERT(remote_name);
 
  hFind = FindFirstFileW(local_name, &fd);
  if (INVALID_HANDLE_VALUE == hFind)
  {
    WLog_ERR(TAG, "FindFirstFile failed (%" PRIu32 ")", GetLastError());
    return NULL;
  }
  FindClose(hFind);
 
  file = calloc(1, sizeof(*file));
  if (!file)
    return NULL;
 
  file->fd = INVALID_HANDLE_VALUE;
  file->offset = 0;
  file->local_name = _wcsdup(local_name);
  if (!file->local_name)
    goto fail;
 
  file->remote_name = _wcsdup(remote_name);
  if (!file->remote_name)
    goto fail;
 
  {
    const size_t len = _wcslen(file->remote_name);
    PathCchConvertStyleW(file->remote_name, len, PATH_STYLE_WINDOWS);
  }
 
  file->dwFileAttributes = fd.dwFileAttributes;
  file->ftCreationTime = fd.ftCreationTime;
  file->ftLastWriteTime = fd.ftLastWriteTime;
  file->ftLastAccessTime = fd.ftLastAccessTime;
  file->nFileSizeHigh = fd.nFileSizeHigh;
  file->nFileSizeLow = fd.nFileSizeLow;
 
  return file;
fail:
  free_synthetic_file(file);
  return NULL;
}
 
static UINT synthetic_file_read_close(struct synthetic_file* file, BOOL force);
 
void free_synthetic_file(struct synthetic_file* file)
{
  if (!file)
    return;
 
  synthetic_file_read_close(file, TRUE);
 
  free(file->local_name);
  free(file->remote_name);
  free(file);
}
 
/*
 * Note that the function converts a single file name component,
 * it does not take care of component separators.
 */
static WCHAR* convert_local_name_component_to_remote(wClipboard* clipboard, const WCHAR* local_name)
{
  wClipboardDelegate* delegate = ClipboardGetDelegate(clipboard);
  WCHAR* remote_name = NULL;
 
  WINPR_ASSERT(delegate);
 
  remote_name = _wcsdup(local_name);
 
  /*
   * Some file names are not valid on Windows. Check for these now
   * so that we won't get ourselves into a trouble later as such names
   * are known to crash some Windows shells when pasted via clipboard.
   *
   * The IsFileNameComponentValid callback can be overridden by the API
   * user, if it is known, that the connected peer is not on the
   * Windows platform.
   */
  if (!delegate->IsFileNameComponentValid(remote_name))
  {
    char name[MAX_PATH] = { 0 };
    ConvertWCharToUtf8(local_name, name, sizeof(name) - 1);
    WLog_ERR(TAG, "invalid file name component: %s", name);
    goto error;
  }
 
  return remote_name;
error:
  free(remote_name);
  return NULL;
}
 
static WCHAR* concat_file_name(const WCHAR* dir, const WCHAR* file)
{
  size_t len_dir = 0;
  size_t len_file = 0;
  const WCHAR slash = '/';
  WCHAR* buffer = NULL;
 
  WINPR_ASSERT(dir);
  WINPR_ASSERT(file);
 
  len_dir = _wcslen(dir);
  len_file = _wcslen(file);
  buffer = calloc(len_dir + 1 + len_file + 2, sizeof(WCHAR));
 
  if (!buffer)
    return NULL;
 
  memcpy(buffer, dir, len_dir * sizeof(WCHAR));
  buffer[len_dir] = slash;
  memcpy(buffer + len_dir + 1, file, len_file * sizeof(WCHAR));
  return buffer;
}
 
static BOOL add_file_to_list(wClipboard* clipboard, const WCHAR* local_name,
                             const WCHAR* remote_name, wArrayList* files);
 
static BOOL add_directory_entry_to_list(wClipboard* clipboard, const WCHAR* local_dir_name,
                                        const WCHAR* remote_dir_name,
                                        const LPWIN32_FIND_DATAW pFileData, wArrayList* files)
{
  BOOL result = FALSE;
  WCHAR* local_name = NULL;
  WCHAR* remote_name = NULL;
  WCHAR* remote_base_name = NULL;
 
  WCHAR dotbuffer[6] = { 0 };
  WCHAR dotdotbuffer[6] = { 0 };
  const WCHAR* dot = InitializeConstWCharFromUtf8(".", dotbuffer, ARRAYSIZE(dotbuffer));
  const WCHAR* dotdot = InitializeConstWCharFromUtf8("..", dotdotbuffer, ARRAYSIZE(dotdotbuffer));
 
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(local_dir_name);
  WINPR_ASSERT(remote_dir_name);
  WINPR_ASSERT(pFileData);
  WINPR_ASSERT(files);
 
  /* Skip special directory entries. */
 
  if ((_wcscmp(pFileData->cFileName, dot) == 0) || (_wcscmp(pFileData->cFileName, dotdot) == 0))
    return TRUE;
 
  remote_base_name = convert_local_name_component_to_remote(clipboard, pFileData->cFileName);
 
  if (!remote_base_name)
    return FALSE;
 
  local_name = concat_file_name(local_dir_name, pFileData->cFileName);
  remote_name = concat_file_name(remote_dir_name, remote_base_name);
 
  if (local_name && remote_name)
    result = add_file_to_list(clipboard, local_name, remote_name, files);
 
  free(remote_base_name);
  free(remote_name);
  free(local_name);
  return result;
}
 
static BOOL do_add_directory_contents_to_list(wClipboard* clipboard, const WCHAR* local_name,
                                              const WCHAR* remote_name, WCHAR* namebuf,
                                              wArrayList* files)
{
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(local_name);
  WINPR_ASSERT(remote_name);
  WINPR_ASSERT(files);
  WINPR_ASSERT(namebuf);
 
  WIN32_FIND_DATAW FindData = { 0 };
  HANDLE hFind = FindFirstFileW(namebuf, &FindData);
  if (INVALID_HANDLE_VALUE == hFind)
  {
    WLog_ERR(TAG, "FindFirstFile failed (%" PRIu32 ")", GetLastError());
    return FALSE;
  }
  while (TRUE)
  {
    if (!add_directory_entry_to_list(clipboard, local_name, remote_name, &FindData, files))
    {
      FindClose(hFind);
      return FALSE;
    }
 
    BOOL bRet = FindNextFileW(hFind, &FindData);
    if (!bRet)
    {
      FindClose(hFind);
      if (ERROR_NO_MORE_FILES == GetLastError())
        return TRUE;
      WLog_WARN(TAG, "FindNextFile failed (%" PRIu32 ")", GetLastError());
      return FALSE;
    }
  }
 
  return TRUE;
}
 
static BOOL add_directory_contents_to_list(wClipboard* clipboard, const WCHAR* local_name,
                                           const WCHAR* remote_name, wArrayList* files)
{
  BOOL result = FALSE;
  union
  {
    const char* c;
    const WCHAR* w;
  } wildcard;
  const char buffer[6] = { '/', '\0', '*', '\0', '\0', '\0' };
  wildcard.c = buffer;
  const size_t wildcardLen = ARRAYSIZE(buffer) / sizeof(WCHAR);
 
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(local_name);
  WINPR_ASSERT(remote_name);
  WINPR_ASSERT(files);
 
  size_t len = _wcslen(local_name);
  WCHAR* namebuf = calloc(len + wildcardLen, sizeof(WCHAR));
  if (!namebuf)
    return FALSE;
 
  _wcsncat(namebuf, local_name, len);
  _wcsncat(namebuf, wildcard.w, wildcardLen);
 
  result = do_add_directory_contents_to_list(clipboard, local_name, remote_name, namebuf, files);
 
  free(namebuf);
  return result;
}
 
static BOOL add_file_to_list(wClipboard* clipboard, const WCHAR* local_name,
                             const WCHAR* remote_name, wArrayList* files)
{
  struct synthetic_file* file = NULL;
 
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(local_name);
  WINPR_ASSERT(remote_name);
  WINPR_ASSERT(files);
 
  file = make_synthetic_file(local_name, remote_name);
 
  if (!file)
    return FALSE;
 
  if (!ArrayList_Append(files, file))
  {
    free_synthetic_file(file);
    return FALSE;
  }
 
  if (file->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
  {
    /*
     * This is effectively a recursive call, but we do not track
     * recursion depth, thus filesystem loops can cause a crash.
     */
    if (!add_directory_contents_to_list(clipboard, local_name, remote_name, files))
      return FALSE;
  }
 
  return TRUE;
}
 
static const WCHAR* get_basename(const WCHAR* name)
{
  const WCHAR* c = name;
  const WCHAR* last_name = name;
  const WCHAR slash = '/';
 
  WINPR_ASSERT(name);
 
  while (*c++)
  {
    if (*c == slash)
      last_name = c + 1;
  }
 
  return last_name;
}
 
static BOOL process_file_name(wClipboard* clipboard, const WCHAR* local_name, wArrayList* files)
{
  BOOL result = FALSE;
  const WCHAR* base_name = NULL;
  WCHAR* remote_name = NULL;
 
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(local_name);
  WINPR_ASSERT(files);
 
  /*
   * Start with the base name of the file. text/uri-list contains the
   * exact files selected by the user, and we want the remote files
   * to have names relative to that selection.
   */
  base_name = get_basename(local_name);
  remote_name = convert_local_name_component_to_remote(clipboard, base_name);
 
  if (!remote_name)
    return FALSE;
 
  result = add_file_to_list(clipboard, local_name, remote_name, files);
  free(remote_name);
  return result;
}
 
static BOOL process_uri(wClipboard* clipboard, const char* uri, size_t uri_len)
{
  // URI is specified by RFC 8089: https://datatracker.ietf.org/doc/html/rfc8089
  BOOL result = FALSE;
  char* name = NULL;
 
  WINPR_ASSERT(clipboard);
 
  name = parse_uri_to_local_file(uri, uri_len);
  if (name)
  {
    WCHAR* wname = NULL;
    /*
     * Note that local file names are not actually guaranteed to be
     * encoded in UTF-8. Filesystems and users can use whatever they
     * want. The OS does not care, aside from special treatment of
     * '\0' and '/' bytes. But we need to make some decision here.
     * Assuming UTF-8 is currently the most sane thing.
     */
    wname = ConvertUtf8ToWCharAlloc(name, NULL);
    if (wname)
      result = process_file_name(clipboard, wname, clipboard->localFiles);
 
    free(name);
    free(wname);
  }
 
  return result;
}
 
static BOOL process_uri_list(wClipboard* clipboard, const char* data, size_t length)
{
  const char* cur = data;
  const char* lim = data + length;
 
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(data);
 
  WLog_VRB(TAG, "processing URI list:\n%.*s", WINPR_ASSERTING_INT_CAST(int, length), data);
  ArrayList_Clear(clipboard->localFiles);
 
  /*
   * The "text/uri-list" Internet Media Type is specified by RFC 2483.
   *
   * While the RFCs 2046 and 2483 require the lines of text/... formats
   * to be terminated by CRLF sequence, be prepared for those who don't
   * read the spec, use plain LFs, and don't leave the trailing CRLF.
   */
 
  while (cur < lim)
  {
    BOOL comment = (*cur == '#');
    const char* start = cur;
    const char* stop = cur;
 
    for (; stop < lim; stop++)
    {
      if (*stop == '\r')
      {
        if ((stop + 1 < lim) && (*(stop + 1) == '\n'))
          cur = stop + 2;
        else
          cur = stop + 1;
 
        break;
      }
 
      if (*stop == '\n')
      {
        cur = stop + 1;
        break;
      }
    }
 
    if (stop == lim)
    {
      if (strnlen(start, WINPR_ASSERTING_INT_CAST(size_t, stop - start)) < 1)
        return TRUE;
      cur = lim;
    }
 
    if (comment)
      continue;
 
    if (!process_uri(clipboard, start, WINPR_ASSERTING_INT_CAST(size_t, stop - start)))
      return FALSE;
  }
 
  return TRUE;
}
 
static BOOL convert_local_file_to_filedescriptor(const struct synthetic_file* file,
                                                 FILEDESCRIPTORW* descriptor)
{
  size_t remote_len = 0;
 
  WINPR_ASSERT(file);
  WINPR_ASSERT(descriptor);
 
  descriptor->dwFlags = FD_ATTRIBUTES | FD_FILESIZE | FD_WRITESTIME | FD_PROGRESSUI;
 
  if (file->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
  {
    descriptor->dwFileAttributes = FILE_ATTRIBUTE_DIRECTORY;
    descriptor->nFileSizeLow = 0;
    descriptor->nFileSizeHigh = 0;
  }
  else
  {
    descriptor->dwFileAttributes = FILE_ATTRIBUTE_NORMAL;
    descriptor->nFileSizeLow = file->nFileSizeLow;
    descriptor->nFileSizeHigh = file->nFileSizeHigh;
  }
 
  descriptor->ftLastWriteTime = file->ftLastWriteTime;
 
  remote_len = _wcsnlen(file->remote_name, ARRAYSIZE(descriptor->cFileName));
 
  if (remote_len >= ARRAYSIZE(descriptor->cFileName))
  {
    WLog_ERR(TAG, "file name too long (%" PRIuz " characters)", remote_len);
    return FALSE;
  }
 
  memcpy(descriptor->cFileName, file->remote_name, remote_len * sizeof(WCHAR));
  return TRUE;
}
 
static FILEDESCRIPTORW* convert_local_file_list_to_filedescriptors(wArrayList* files)
{
  size_t count = 0;
  FILEDESCRIPTORW* descriptors = NULL;
 
  count = ArrayList_Count(files);
 
  descriptors = calloc(count, sizeof(FILEDESCRIPTORW));
 
  if (!descriptors)
    goto error;
 
  for (size_t i = 0; i < count; i++)
  {
    const struct synthetic_file* file = ArrayList_GetItem(files, i);
 
    if (!convert_local_file_to_filedescriptor(file, &descriptors[i]))
      goto error;
  }
 
  return descriptors;
error:
  free(descriptors);
  return NULL;
}
 
static void* convert_any_uri_list_to_filedescriptors(wClipboard* clipboard,
                                                     WINPR_ATTR_UNUSED UINT32 formatId,
                                                     UINT32* pSize)
{
  FILEDESCRIPTORW* descriptors = NULL;
 
  WINPR_ASSERT(clipboard);
  WINPR_ASSERT(pSize);
 
  descriptors = convert_local_file_list_to_filedescriptors(clipboard->localFiles);
  *pSize = 0;
  if (!descriptors)
    return NULL;
 
  *pSize = (UINT32)ArrayList_Count(clipboard->localFiles) * sizeof(FILEDESCRIPTORW);
  clipboard->fileListSequenceNumber = clipboard->sequenceNumber;
  return descriptors;
}
 
static void* convert_uri_list_to_filedescriptors(wClipboard* clipboard, UINT32 formatId,
                                                 const void* data, UINT32* pSize)
{
  const UINT32 expected = ClipboardGetFormatId(clipboard, mime_uri_list);
  if (formatId != expected)
    return NULL;
  if (!process_uri_list(clipboard, (const char*)data, *pSize))
    return NULL;
  return convert_any_uri_list_to_filedescriptors(clipboard, formatId, pSize);
}
 
static BOOL process_files(wClipboard* clipboard, const char* data, UINT32 pSize, const char* prefix)
{
  WINPR_ASSERT(prefix);
 
  const size_t prefix_len = strlen(prefix);
 
  WINPR_ASSERT(clipboard);
 
  ArrayList_Clear(clipboard->localFiles);
 
  if (!data || (pSize < prefix_len))
    return FALSE;
  if (strncmp(data, prefix, prefix_len) != 0)
    return FALSE;
  data += prefix_len;
  if (pSize < prefix_len)
    return FALSE;
  pSize -= WINPR_ASSERTING_INT_CAST(uint32_t, prefix_len);
 
  BOOL rc = FALSE;
  char* copy = strndup(data, pSize);
  if (!copy)
    goto fail;
 
  {
    char* endptr = NULL;
    char* tok = strtok_s(copy, "\n", &endptr);
    while (tok)
    {
      const size_t tok_len = strnlen(tok, pSize);
      if (!process_uri(clipboard, tok, tok_len))
        goto fail;
      if (pSize < tok_len)
        goto fail;
      pSize -= WINPR_ASSERTING_INT_CAST(uint32_t, tok_len);
      tok = strtok_s(NULL, "\n", &endptr);
    }
  }
 
  rc = TRUE;
 
fail:
  free(copy);
  return rc;
}
 
static BOOL process_gnome_copied_files(wClipboard* clipboard, const char* data, UINT32 pSize)
{
  return process_files(clipboard, data, pSize, "copy\n");
}
 
static BOOL process_mate_copied_files(wClipboard* clipboard, const char* data, UINT32 pSize)
{
  return process_files(clipboard, data, pSize, "copy\n");
}
 
static void* convert_gnome_copied_files_to_filedescriptors(wClipboard* clipboard, UINT32 formatId,
                                                           const void* data, UINT32* pSize)
{
  const UINT32 expected = ClipboardGetFormatId(clipboard, mime_gnome_copied_files);
  if (formatId != expected)
    return NULL;
  if (!process_gnome_copied_files(clipboard, (const char*)data, *pSize))
    return NULL;
  return convert_any_uri_list_to_filedescriptors(clipboard, formatId, pSize);
}
 
static void* convert_mate_copied_files_to_filedescriptors(wClipboard* clipboard, UINT32 formatId,
                                                          const void* data, UINT32* pSize)
{
  const UINT32 expected = ClipboardGetFormatId(clipboard, mime_mate_copied_files);
  if (formatId != expected)
    return NULL;
 
  if (!process_mate_copied_files(clipboard, (const char*)data, *pSize))
    return NULL;
 
  return convert_any_uri_list_to_filedescriptors(clipboard, formatId, pSize);
}
 
static size_t count_special_chars(const WCHAR* str)
{
  size_t count = 0;
  const WCHAR* start = str;
 
  WINPR_ASSERT(str);
  while (*start)
  {
    const WCHAR sharp = '#';
    const WCHAR questionmark = '?';
    const WCHAR star = '*';
    const WCHAR exclamationmark = '!';
    const WCHAR percent = '%';
 
    if ((*start == sharp) || (*start == questionmark) || (*start == star) ||
        (*start == exclamationmark) || (*start == percent))
    {
      count++;
    }
    start++;
  }
  return count;
}
 
static const char* stop_at_special_chars(const char* str)
{
  const char* start = str;
  WINPR_ASSERT(str);
 
  while (*start)
  {
    if (*start == '#' || *start == '?' || *start == '*' || *start == '!' || *start == '%')
    {
      return start;
    }
    start++;
  }
  return NULL;
}
 
/* The universal converter from filedescriptors to different file lists */
static void* convert_filedescriptors_to_file_list(wClipboard* clipboard, UINT32 formatId,
                                                  const void* data, UINT32* pSize,
                                                  const char* header, const char* lineprefix,
                                                  const char* lineending, BOOL skip_last_lineending)
{
  union
  {
    char c[2];
    WCHAR w;
  } backslash;
  backslash.c[0] = '\\';
  backslash.c[1] = '\0';
 
  const FILEDESCRIPTORW* descriptors = NULL;
  UINT32 nrDescriptors = 0;
  size_t count = 0;
  size_t alloc = 0;
  size_t pos = 0;
  size_t baseLength = 0;
  char* dst = NULL;
  size_t header_len = strlen(header);
  size_t lineprefix_len = strlen(lineprefix);
  size_t lineending_len = strlen(lineending);
  size_t decoration_len = 0;
 
  if (!clipboard || !data || !pSize)
    return NULL;
 
  if (*pSize < sizeof(UINT32))
    return NULL;
 
  if (clipboard->delegate.basePath)
    baseLength = strnlen(clipboard->delegate.basePath, MAX_PATH);
 
  if (baseLength < 1)
    return NULL;
 
  wStream sbuffer = { 0 };
  wStream* s = Stream_StaticConstInit(&sbuffer, data, *pSize);
  if (!Stream_CheckAndLogRequiredLength(TAG, s, 4))
    return NULL;
 
  Stream_Read_UINT32(s, nrDescriptors);
 
  count = (*pSize - 4) / sizeof(FILEDESCRIPTORW);
 
  if ((count < 1) || (count != nrDescriptors))
    return NULL;
 
  descriptors = Stream_ConstPointer(s);
 
  if (formatId != ClipboardGetFormatId(clipboard, mime_FileGroupDescriptorW))
    return NULL;
 
  /* Plus 1 for '/' between basepath and filename*/
  decoration_len = lineprefix_len + lineending_len + baseLength + 1;
  alloc = header_len;
 
  /* Get total size of file/folder names under first level folder only */
  for (size_t x = 0; x < count; x++)
  {
    const FILEDESCRIPTORW* dsc = &descriptors[x];
 
    if (_wcschr(dsc->cFileName, backslash.w) == NULL)
    {
      alloc += ARRAYSIZE(dsc->cFileName) *
               8; /* Overallocate, just take the biggest value the result path can have */
                  /* # (1 char) -> %23 (3 chars) , the first char is replaced inplace */
      alloc += count_special_chars(dsc->cFileName) * 2;
      alloc += decoration_len;
    }
  }
 
  /* Append a prefix file:// and postfix \n for each file */
  /* We need to keep last \n since snprintf is null terminated!!  */
  alloc++;
  dst = calloc(alloc, sizeof(char));
 
  if (!dst)
    return NULL;
 
  (void)_snprintf(&dst[0], alloc, "%s", header);
 
  pos = header_len;
 
  for (size_t x = 0; x < count; x++)
  {
    const FILEDESCRIPTORW* dsc = &descriptors[x];
    BOOL fail = TRUE;
    if (_wcschr(dsc->cFileName, backslash.w) != NULL)
    {
      continue;
    }
    int rc = -1;
    char curName[520] = { 0 };
    const char* stop_at = NULL;
    const char* previous_at = NULL;
 
    if (ConvertWCharNToUtf8(dsc->cFileName, ARRAYSIZE(dsc->cFileName), curName,
                            ARRAYSIZE(curName)) < 0)
      goto loop_fail;
 
    rc = _snprintf(&dst[pos], alloc - pos, "%s%s/", lineprefix, clipboard->delegate.basePath);
 
    if (rc < 0)
      goto loop_fail;
 
    pos += (size_t)rc;
 
    previous_at = curName;
    while ((stop_at = stop_at_special_chars(previous_at)) != NULL)
    {
      const intptr_t diff = stop_at - previous_at;
      if (diff < 0)
        goto loop_fail;
      char* tmp = strndup(previous_at, WINPR_ASSERTING_INT_CAST(size_t, diff));
      if (!tmp)
        goto loop_fail;
 
      rc = _snprintf(&dst[pos], WINPR_ASSERTING_INT_CAST(size_t, diff + 1), "%s", tmp);
      free(tmp);
      if (rc < 0)
        goto loop_fail;
 
      pos += (size_t)rc;
      rc = _snprintf(&dst[pos], 4, "%%%x", *stop_at);
      if (rc < 0)
        goto loop_fail;
 
      pos += (size_t)rc;
      previous_at = stop_at + 1;
    }
 
    rc = _snprintf(&dst[pos], alloc - pos, "%s%s", previous_at, lineending);
 
    fail = FALSE;
  loop_fail:
    if ((rc < 0) || fail)
    {
      free(dst);
      return NULL;
    }
 
    pos += (size_t)rc;
  }
 
  if (skip_last_lineending)
  {
    const size_t endlen = strlen(lineending);
    if (alloc > endlen)
    {
      const size_t len = strnlen(dst, alloc);
      if (len < endlen)
      {
        free(dst);
        return NULL;
      }
 
      if (memcmp(&dst[len - endlen], lineending, endlen) == 0)
      {
        memset(&dst[len - endlen], 0, endlen);
        alloc -= endlen;
      }
    }
  }
 
  alloc = strnlen(dst, alloc) + 1;
  *pSize = (UINT32)alloc;
  clipboard->fileListSequenceNumber = clipboard->sequenceNumber;
  return dst;
}
 
/* Prepend header of kde dolphin format to file list
 * See:
 *   GTK: https://docs.gtk.org/glib/struct.Uri.html
 *   uri syntax: https://www.rfc-editor.org/rfc/rfc3986#section-3
 *   uri-lists format: https://www.rfc-editor.org/rfc/rfc2483#section-5
 */
static void* convert_filedescriptors_to_uri_list(wClipboard* clipboard, UINT32 formatId,
                                                 const void* data, UINT32* pSize)
{
  return convert_filedescriptors_to_file_list(clipboard, formatId, data, pSize, "", "file://",
                                              "\r\n", FALSE);
}
 
/* Prepend header of common gnome format to file list*/
static void* convert_filedescriptors_to_gnome_copied_files(wClipboard* clipboard, UINT32 formatId,
                                                           const void* data, UINT32* pSize)
{
  return convert_filedescriptors_to_file_list(clipboard, formatId, data, pSize, "copy\n",
                                              "file://", "\n", TRUE);
}
 
static void* convert_filedescriptors_to_mate_copied_files(wClipboard* clipboard, UINT32 formatId,
                                                          const void* data, UINT32* pSize)
{
 
  char* pDstData = convert_filedescriptors_to_file_list(clipboard, formatId, data, pSize,
                                                        "copy\n", "file://", "\n", TRUE);
  if (!pDstData)
  {
    return pDstData;
  }
  /*  Replace last \n with \0
      see
     mate-desktop/caja/libcaja-private/caja-clipboard.c:caja_clipboard_get_uri_list_from_selection_data
  */
 
  pDstData[*pSize - 1] = '\0';
  *pSize = *pSize - 1;
  return pDstData;
}
 
static void array_free_synthetic_file(void* the_file)
{
  struct synthetic_file* file = the_file;
  free_synthetic_file(file);
}
 
static BOOL register_file_formats_and_synthesizers(wClipboard* clipboard)
{
  wObject* obj = NULL;
 
  /*
      1. Gnome Nautilus based file manager (Nautilus only with version >= 3.30 AND < 40):
          TARGET: UTF8_STRING
          format: x-special/nautilus-clipboard\copy\n\file://path\n\0
      2. Kde Dolpin and Qt:
          TARGET: text/uri-list
          format: file:path\r\n\0
          See:
            GTK: https://docs.gtk.org/glib/struct.Uri.html
            uri syntax: https://www.rfc-editor.org/rfc/rfc3986#section-3
            uri-lists format: https://www.rfc-editor.org/rfc/rfc2483#section-5
      3. Gnome and others (Unity/XFCE/Nautilus < 3.30/Nautilus >= 40):
          TARGET: x-special/gnome-copied-files
          format: copy\nfile://path\n\0
      4. Mate Caja:
          TARGET: x-special/mate-copied-files
          format: copy\nfile://path\n
 
      TODO: other file managers do not use previous targets and formats.
  */
 
  const UINT32 local_gnome_file_format_id =
      ClipboardRegisterFormat(clipboard, mime_gnome_copied_files);
  const UINT32 local_mate_file_format_id =
      ClipboardRegisterFormat(clipboard, mime_mate_copied_files);
  const UINT32 file_group_format_id =
      ClipboardRegisterFormat(clipboard, mime_FileGroupDescriptorW);
  const UINT32 local_file_format_id = ClipboardRegisterFormat(clipboard, mime_uri_list);
 
  if (!file_group_format_id || !local_file_format_id || !local_gnome_file_format_id ||
      !local_mate_file_format_id)
    goto error;
 
  clipboard->localFiles = ArrayList_New(FALSE);
 
  if (!clipboard->localFiles)
    goto error;
 
  obj = ArrayList_Object(clipboard->localFiles);
  obj->fnObjectFree = array_free_synthetic_file;
 
  if (!ClipboardRegisterSynthesizer(clipboard, local_file_format_id, file_group_format_id,
                                    convert_uri_list_to_filedescriptors))
    goto error_free_local_files;
 
  if (!ClipboardRegisterSynthesizer(clipboard, file_group_format_id, local_file_format_id,
                                    convert_filedescriptors_to_uri_list))
    goto error_free_local_files;
 
  if (!ClipboardRegisterSynthesizer(clipboard, local_gnome_file_format_id, file_group_format_id,
                                    convert_gnome_copied_files_to_filedescriptors))
    goto error_free_local_files;
 
  if (!ClipboardRegisterSynthesizer(clipboard, file_group_format_id, local_gnome_file_format_id,
                                    convert_filedescriptors_to_gnome_copied_files))
    goto error_free_local_files;
 
  if (!ClipboardRegisterSynthesizer(clipboard, local_mate_file_format_id, file_group_format_id,
                                    convert_mate_copied_files_to_filedescriptors))
    goto error_free_local_files;
 
  if (!ClipboardRegisterSynthesizer(clipboard, file_group_format_id, local_mate_file_format_id,
                                    convert_filedescriptors_to_mate_copied_files))
    goto error_free_local_files;
 
  return TRUE;
error_free_local_files:
  ArrayList_Free(clipboard->localFiles);
  clipboard->localFiles = NULL;
error:
  return FALSE;
}
 
static int32_t file_get_size(const struct synthetic_file* file, UINT64* size)
{
  UINT64 s = 0;
 
  if (!file || !size)
    return E_INVALIDARG;
 
  s = file->nFileSizeHigh;
  s <<= 32;
  s |= file->nFileSizeLow;
  *size = s;
  return NO_ERROR;
}
 
static UINT delegate_file_request_size(wClipboardDelegate* delegate,
                                       const wClipboardFileSizeRequest* request)
{
  UINT64 size = 0;
 
  if (!delegate || !delegate->clipboard || !request)
    return ERROR_BAD_ARGUMENTS;
 
  if (delegate->clipboard->sequenceNumber != delegate->clipboard->fileListSequenceNumber)
    return ERROR_INVALID_STATE;
 
  struct synthetic_file* file =
      ArrayList_GetItem(delegate->clipboard->localFiles, request->listIndex);
 
  if (!file)
    return ERROR_INDEX_ABSENT;
 
  const int32_t s = file_get_size(file, &size);
  uint32_t error = 0;
  if (error)
    error = delegate->ClipboardFileSizeFailure(delegate, request, (UINT)s);
  else
    error = delegate->ClipboardFileSizeSuccess(delegate, request, size);
 
  if (error)
    WLog_WARN(TAG, "failed to report file size result: 0x%08X", error);
 
  return NO_ERROR;
}
 
UINT synthetic_file_read_close(struct synthetic_file* file, BOOL force)
{
  if (!file || INVALID_HANDLE_VALUE == file->fd)
    return NO_ERROR;
 
  /* Always force close the file. Clipboard might open hundreds of files
   * so avoid caching to prevent running out of available file descriptors */
  UINT64 size = 0;
  file_get_size(file, &size);
  if ((file->offset < 0) || ((UINT64)file->offset >= size) || force)
  {
    WLog_VRB(TAG, "close file %p", file->fd);
    if (!CloseHandle(file->fd))
    {
      WLog_WARN(TAG, "failed to close fd %p: %" PRIu32, file->fd, GetLastError());
    }
 
    file->fd = INVALID_HANDLE_VALUE;
  }
 
  return NO_ERROR;
}
 
static UINT file_get_range(struct synthetic_file* file, UINT64 offset, UINT32 size,
                           BYTE** actual_data, UINT32* actual_size)
{
  UINT error = NO_ERROR;
  DWORD dwLow = 0;
  DWORD dwHigh = 0;
 
  WINPR_ASSERT(file);
  WINPR_ASSERT(actual_data);
  WINPR_ASSERT(actual_size);
 
  if (INVALID_HANDLE_VALUE == file->fd)
  {
    BY_HANDLE_FILE_INFORMATION FileInfo = { 0 };
 
    file->fd = CreateFileW(file->local_name, GENERIC_READ, 0, NULL, OPEN_EXISTING,
                           FILE_ATTRIBUTE_NORMAL, NULL);
    if (INVALID_HANDLE_VALUE == file->fd)
    {
      char name[MAX_PATH] = { 0 };
      ConvertWCharToUtf8(file->local_name, name, sizeof(name) - 1);
      error = GetLastError();
      WLog_ERR(TAG, "failed to open file %s: 0x%08" PRIx32, name, error);
      return error;
    }
 
    if (!GetFileInformationByHandle(file->fd, &FileInfo))
    {
      char name[MAX_PATH] = { 0 };
      ConvertWCharToUtf8(file->local_name, name, sizeof(name) - 1);
      (void)CloseHandle(file->fd);
      file->fd = INVALID_HANDLE_VALUE;
      error = GetLastError();
      WLog_ERR(TAG, "Get file [%s] information fail: 0x%08" PRIx32, name, error);
      return error;
    }
 
    file->offset = 0;
    file->nFileSizeHigh = FileInfo.nFileSizeHigh;
    file->nFileSizeLow = FileInfo.nFileSizeLow;
 
    /*
    {
        UINT64 s = 0;
        file_get_size(file, &s);
        WLog_DBG(TAG, "open file %d -> %s", file->fd, file->local_name);
        WLog_DBG(TAG, "file %d size: %" PRIu64 " bytes", file->fd, s);
    } //*/
  }
 
  do
  {
    /*
     * We should avoid seeking when possible as some filesystems (e.g.,
     * an FTP server mapped via FUSE) may not support seeking. We keep
     * an accurate account of the current file offset and do not call
     * lseek() if the client requests file content sequentially.
     */
    if (offset > INT64_MAX)
    {
      WLog_ERR(TAG, "offset [%" PRIu64 "] > INT64_MAX", offset);
      error = ERROR_SEEK;
      break;
    }
 
    if (file->offset != (INT64)offset)
    {
      WLog_DBG(TAG, "file %p force seeking to %" PRIu64 ", current %" PRId64, file->fd,
               offset, file->offset);
 
      dwHigh = offset >> 32;
      dwLow = offset & 0xFFFFFFFF;
      if (INVALID_SET_FILE_POINTER == SetFilePointer(file->fd,
                                                     WINPR_ASSERTING_INT_CAST(LONG, dwLow),
                                                     (PLONG)&dwHigh, FILE_BEGIN))
      {
        error = GetLastError();
        break;
      }
    }
 
    BYTE* buffer = malloc(size);
    if (!buffer)
    {
      error = ERROR_NOT_ENOUGH_MEMORY;
      break;
    }
    if (!ReadFile(file->fd, buffer, size, (LPDWORD)actual_size, NULL))
    {
      free(buffer);
      error = GetLastError();
      break;
    }
 
    *actual_data = buffer;
    file->offset += *actual_size;
    WLog_VRB(TAG, "file %p actual read %" PRIu32 " bytes (offset %" PRId64 ")", file->fd,
             *actual_size, file->offset);
  } while (0);
 
  synthetic_file_read_close(file, TRUE /* (error != NO_ERROR) && (size > 0) */);
  return error;
}
 
static UINT delegate_file_request_range(wClipboardDelegate* delegate,
                                        const wClipboardFileRangeRequest* request)
{
  UINT error = 0;
  BYTE* data = NULL;
  UINT32 size = 0;
  UINT64 offset = 0;
  struct synthetic_file* file = NULL;
 
  if (!delegate || !delegate->clipboard || !request)
    return ERROR_BAD_ARGUMENTS;
 
  if (delegate->clipboard->sequenceNumber != delegate->clipboard->fileListSequenceNumber)
    return ERROR_INVALID_STATE;
 
  file = ArrayList_GetItem(delegate->clipboard->localFiles, request->listIndex);
 
  if (!file)
    return ERROR_INDEX_ABSENT;
 
  offset = (((UINT64)request->nPositionHigh) << 32) | ((UINT64)request->nPositionLow);
  error = file_get_range(file, offset, request->cbRequested, &data, &size);
 
  if (error)
    error = delegate->ClipboardFileRangeFailure(delegate, request, error);
  else
    error = delegate->ClipboardFileRangeSuccess(delegate, request, data, size);
 
  if (error)
    WLog_WARN(TAG, "failed to report file range result: 0x%08X", error);
 
  free(data);
  return NO_ERROR;
}
 
static UINT dummy_file_size_success(WINPR_ATTR_UNUSED wClipboardDelegate* delegate,
                                    WINPR_ATTR_UNUSED const wClipboardFileSizeRequest* request,
                                    WINPR_ATTR_UNUSED UINT64 fileSize)
{
  return ERROR_NOT_SUPPORTED;
}
 
static UINT dummy_file_size_failure(WINPR_ATTR_UNUSED wClipboardDelegate* delegate,
                                    WINPR_ATTR_UNUSED const wClipboardFileSizeRequest* request,
                                    WINPR_ATTR_UNUSED UINT errorCode)
{
  return ERROR_NOT_SUPPORTED;
}
 
static UINT dummy_file_range_success(WINPR_ATTR_UNUSED wClipboardDelegate* delegate,
                                     WINPR_ATTR_UNUSED const wClipboardFileRangeRequest* request,
                                     WINPR_ATTR_UNUSED const BYTE* data,
                                     WINPR_ATTR_UNUSED UINT32 size)
{
  return ERROR_NOT_SUPPORTED;
}
 
static UINT dummy_file_range_failure(WINPR_ATTR_UNUSED wClipboardDelegate* delegate,
                                     WINPR_ATTR_UNUSED const wClipboardFileRangeRequest* request,
                                     WINPR_ATTR_UNUSED UINT errorCode)
{
  return ERROR_NOT_SUPPORTED;
}
 
static void setup_delegate(wClipboardDelegate* delegate)
{
  WINPR_ASSERT(delegate);
 
  delegate->ClientRequestFileSize = delegate_file_request_size;
  delegate->ClipboardFileSizeSuccess = dummy_file_size_success;
  delegate->ClipboardFileSizeFailure = dummy_file_size_failure;
  delegate->ClientRequestFileRange = delegate_file_request_range;
  delegate->ClipboardFileRangeSuccess = dummy_file_range_success;
  delegate->ClipboardFileRangeFailure = dummy_file_range_failure;
  delegate->IsFileNameComponentValid = ValidFileNameComponent;
}
 
BOOL ClipboardInitSyntheticFileSubsystem(wClipboard* clipboard)
{
  if (!clipboard)
    return FALSE;
 
  if (!register_file_formats_and_synthesizers(clipboard))
    return FALSE;
 
  setup_delegate(&clipboard->delegate);
  return TRUE;
}