src/java.base/windows/native/libjli/java_md.c

rev 54213 : 8218547: Simplify JLI_Open on Windows in native code (libjli)

*** 39,50 ****
  #include "java.h"
  
  #define JVM_DLL "jvm.dll"
  #define JAVA_DLL "java.dll"
  
- #define ELP_PREFIX L"\\\\?\\"
- 
  /*
   * Prototypes.
   */
  static jboolean GetJVMPath(const char *jrepath, const char *jvmtype,
                             char *jvmpath, jint jvmpathsize);
--- 39,48 ----
*** 495,555 ****
          buffer[size - 1] = '\0';
      }
      return rc;
  }
  
! /* On Windows, if _open fails, retry again with CreateFileW and
!  *  "\\?\" prefix ( extended-length paths) - this allows to open paths with larger file names;
!  * otherwise we run into the MAX_PATH limitation */
  int JLI_Open(const char* name, int flags) {
!     int fd = _open(name, flags);
!     if (fd == -1 && errno == ENOENT) {
!         wchar_t* wname = NULL;
!         wchar_t* wfullname = NULL;
!         wchar_t* wfullname_w_prefix = NULL;
!         size_t wnamelen, wfullnamelen, elplen;
!         HANDLE h;
! 
!         wnamelen = strlen(name) + 1;
!         wname = (wchar_t*) malloc(wnamelen*sizeof(wchar_t));
!         if (wname == NULL) {
!             goto end;
!         }
!         if (mbstowcs(wname, name, wnamelen - 1) == -1) {
!             goto end;
!         }
!         wname[wnamelen - 1] = L'\0';
!         wfullname = _wfullpath(wfullname, wname, 0);
!         if (wfullname == NULL) {
!             goto end;
!         }
! 
!         wfullnamelen = wcslen(wfullname);
!         if (wfullnamelen > 247) {
!             elplen = wcslen(ELP_PREFIX);
!             wfullname_w_prefix = (wchar_t*) malloc((elplen+wfullnamelen+1)*sizeof(wchar_t));
!             wcscpy(wfullname_w_prefix, ELP_PREFIX);
!             wcscpy(wfullname_w_prefix+elplen, wfullname);
! 
!             h = CreateFileW(wfullname_w_prefix, GENERIC_READ, FILE_SHARE_READ, NULL,
!                             OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
!             if (h == INVALID_HANDLE_VALUE) {
!                 goto end;
!             }
!             /* associates fd with handle */
!             fd = _open_osfhandle((intptr_t)h, _O_RDONLY);
!         }
! end:
!         free(wname);
!         free(wfullname);
!         free(wfullname_w_prefix);
      }
      return fd;
  }
  
- 
- 
  JNIEXPORT void JNICALL
  JLI_ReportErrorMessage(const char* fmt, ...) {
      va_list vl;
      va_start(vl,fmt);
  
--- 493,561 ----
          buffer[size - 1] = '\0';
      }
      return rc;
  }
  
! /* taken from hotspot and slightly adjusted for jli lib; creates a UNC/ELP path from input 'path'
!  * the return buffer is allocated in C heap and needs to be freed using JLI_MemFree by the caller.
!  */
! static wchar_t* create_unc_path(const char* path, errno_t* err) {
!     wchar_t* wpath = NULL;
!     size_t converted_chars = 0;
!     size_t path_len = strlen(path) + 1; /* includes the terminating NULL */
!     if (path[0] == '\\' && path[1] == '\\') {
!         if (path[2] == '?' && path[3] == '\\') {
!             /* if it already has a \\?\ don't do the prefix */
!             wpath = (wchar_t*) JLI_MemAlloc(path_len * sizeof(wchar_t));
!             if (wpath != NULL) {
!                 *err = mbstowcs_s(&converted_chars, wpath, path_len, path, path_len);
!             } else {
!                 *err = ENOMEM;
!             }
!         } else {
!             /* only UNC pathname includes double slashes here */
!             wpath = (wchar_t*) JLI_MemAlloc((path_len + 7) * sizeof(wchar_t));
!             if (wpath != NULL) {
!                 wcscpy(wpath, L"\\\\?\\UNC\0");
!                 *err = mbstowcs_s(&converted_chars, &wpath[7], path_len, path, path_len);
!             } else {
!                 *err = ENOMEM;
!             }
!         }
!     } else {
!         wpath = (wchar_t*) JLI_MemAlloc((path_len + 4) * sizeof(wchar_t));
!         if (wpath != NULL) {
!             wcscpy(wpath, L"\\\\?\\\0");
!             *err = mbstowcs_s(&converted_chars, &wpath[4], path_len, path, path_len);
!         } else {
!             *err = ENOMEM;
!         }
!     }
!     return wpath;
! }
! 
  int JLI_Open(const char* name, int flags) {
!     int fd;
!     if (strlen(name) < MAX_PATH) {
!         fd = _open(name, flags);
!     } else {
!         errno_t err = ERROR_SUCCESS;
!         wchar_t* wpath = create_unc_path(name, &err);
!         if (err != ERROR_SUCCESS) {
!             if (wpath != NULL) JLI_MemFree(wpath);
!             errno = err;
!             return -1;
!         }
!         fd = _wopen(wpath, flags);
!         if (fd == -1) {
!             errno = GetLastError();
!         }
!         JLI_MemFree(wpath);
      }
      return fd;
  }
  
  JNIEXPORT void JNICALL
  JLI_ReportErrorMessage(const char* fmt, ...) {
      va_list vl;
      va_start(vl,fmt);