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

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Reviewed-by: alanb, clanger
This commit is contained in:
Matthias Baesken 2019-04-02 13:54:00 +02:00
parent d6c2cc2413
commit 77ae10cd25
2 changed files with 81 additions and 63 deletions
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102
src/java.base/windows/native/libjli/java_md.c
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@ -41,8 +41,6 @@
#define JVM_DLL "jvm.dll"
#define JAVA_DLL "java.dll"
#define ELP_PREFIX L"\\\\?\\"
/*
* Prototypes.
*/
@ -497,57 +495,67 @@ JLI_Snprintf(char* buffer, size_t size, const char* format, ...) {
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;
/* 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;
}
/* associates fd with handle */
fd = _open_osfhandle((intptr_t)h, _O_RDONLY);
}
end:
free(wname);
free(wfullname);
free(wfullname_w_prefix);
} 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;