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authorBlaine Whittle <[email protected]>2010-10-04 15:29:28 -0700
committerBjörn Gustavsson <[email protected]>2010-10-14 16:15:33 +0200
commit1f6d7c8729176c41dd5eda1ff2b0de8f48b6de95 (patch)
tree8c8940172c417e49eb2de4dd1ecd385440107a00
parent3cfec17ff7aff97c5ec862a8b9e97d245849f9c3 (diff)
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Add Win32 support for hard and symbolic file system links
Hard linking requires XP or later and a NTFS formatted drive. Symbolic linking requires Windows Vista, Windows Server 2008, Windows 7 or later. Symbolic linking on earlier versions of Windows will return {error, enotsup}. file:make_link/2, file:make_sym_link/2 and file:read_link/1 are all implemented. file:read_file_info/1 does NOT return the number of hard links on the file as this results in performance problems for read_file_info/1, however this can be enabled by uncommenting a few lines of code. The original path was submitted on 9/2/2009 by Alex Tearse-Doyle.
-rwxr-xr-x[-rw-r--r--]erts/emulator/drivers/win32/win_efile.c113
1 files changed, 109 insertions, 4 deletions
diff --git a/erts/emulator/drivers/win32/win_efile.c b/erts/emulator/drivers/win32/win_efile.c
index 04bd1139f5..88dd42b42a 100644..100755
--- a/erts/emulator/drivers/win32/win_efile.c
+++ b/erts/emulator/drivers/win32/win_efile.c
@@ -862,6 +862,7 @@ efile_fileinfo(Efile_error* errInfo, Efile_info* pInfo,
findbuf.nFileSizeLow = 0;
findbuf.cFileName[0] = '\0';
+ pInfo->links = 1;
pInfo->modifyTime.year = 1980;
pInfo->modifyTime.month = 1;
pInfo->modifyTime.day = 1;
@@ -874,6 +875,33 @@ efile_fileinfo(Efile_error* errInfo, Efile_info* pInfo,
SYSTEMTIME SystemTime;
FILETIME LocalFTime;
+ /*first check if we are a symlink */
+ if (!info_for_link && (findbuf.dwFileAttributes &
+ FILE_ATTRIBUTE_REPARSE_POINT)){
+ /*
+ * given that we know this is a symlink,
+ we should be able to find its target */
+ char target_name[256];
+ if (efile_readlink(errInfo, name, target_name,256) == 1) {
+ return efile_fileinfo(errInfo, pInfo,
+ target_name, info_for_link);
+ }
+ }
+
+#if 0
+ /* number of links: */
+ {
+ HANDLE handle; /* Handle returned by CreateFile() */
+ BY_HANDLE_FILE_INFORMATION fileInfo; /* from CreateFile() */
+ if (handle = CreateFile(name, GENERIC_READ, 0,NULL,
+ OPEN_EXISTING, 0, NULL)) {
+ GetFileInformationByHandle(handle, &fileInfo);
+ pInfo->links = fileInfo.nNumberOfLinks;
+ CloseHandle(handle);
+ }
+ }
+#endif
+
#define GET_TIME(dst, src) \
if (!FileTimeToLocalFileTime(&findbuf.src, &LocalFTime) || \
!FileTimeToSystemTime(&LocalFTime, &SystemTime)) { \
@@ -908,7 +936,10 @@ if (!FileTimeToLocalFileTime(&findbuf.src, &LocalFTime) || \
pInfo->size_low = findbuf.nFileSizeLow;
pInfo->size_high = findbuf.nFileSizeHigh;
- if (findbuf.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+ if (info_for_link && (findbuf.dwFileAttributes &
+ FILE_ATTRIBUTE_REPARSE_POINT))
+ pInfo->type = FT_SYMLINK;
+ else if (findbuf.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
pInfo->type = FT_DIRECTORY;
else
pInfo->type = FT_REGULAR;
@@ -919,7 +950,6 @@ if (!FileTimeToLocalFileTime(&findbuf.src, &LocalFTime) || \
pInfo->access = FA_READ|FA_WRITE;
pInfo->mode = dos_to_posix_mode(findbuf.dwFileAttributes, name);
- pInfo->links = 1;
pInfo->major_device = drive;
pInfo->minor_device = 0;
pInfo->inode = 0;
@@ -1343,6 +1373,48 @@ dos_to_posix_mode(int attr, const char *name)
int
efile_readlink(Efile_error* errInfo, char* name, char* buffer, size_t size)
{
+ /*
+ * load dll and see if we have CreateSymbolicLink at runtime:
+ * (Vista only)
+ */
+ HINSTANCE hModule = NULL;
+ if ((hModule = LoadLibrary("kernel32.dll")) != NULL) {
+ typedef DWORD (WINAPI * GETFINALPATHNAMEBYHANDLEPTR)(
+ HANDLE hFile,
+ LPCSTR lpFilePath,
+ DWORD cchFilePath,
+ DWORD dwFlags);
+
+ GETFINALPATHNAMEBYHANDLEPTR pGetFinalPathNameByHandle =
+ (GETFINALPATHNAMEBYHANDLEPTR)GetProcAddress(hModule, "GetFinalPathNameByHandleA");
+
+ if (pGetFinalPathNameByHandle == NULL) {
+ FreeLibrary(hModule);
+ } else {
+ /* first check if file is a symlink; {error, einval} otherwise */
+ DWORD fileAttributes = GetFileAttributes(name);
+ if ((fileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
+ BOOLEAN success = 0;
+ HANDLE h = CreateFile(name, GENERIC_READ, 0,NULL, OPEN_EXISTING, 0, NULL);
+ if(h != INVALID_HANDLE_VALUE) {
+ success = pGetFinalPathNameByHandle(h, buffer, size,0);
+ /* GetFinalPathNameByHandle prepends path with "\\?\": */
+ sprintf(buffer, buffer+4);
+ CloseHandle(h);
+ }
+ FreeLibrary(hModule);
+ if (success) {
+ return 1;
+ } else {
+ return set_error(errInfo);
+ }
+ } else {
+ FreeLibrary(hModule);
+ errno = EINVAL;
+ return check_error(-1, errInfo);
+ }
+ }
+ }
errno = ENOTSUP;
return check_error(-1, errInfo);
}
@@ -1427,13 +1499,46 @@ efile_altname(Efile_error* errInfo, char* orig_name, char* buffer, size_t size)
int
efile_link(Efile_error* errInfo, char* old, char* new)
{
- errno = ENOTSUP;
- return check_error(-1, errInfo);
+ if(!CreateHardLink(new, old, NULL)) {
+ return set_error(errInfo);
+ }
+ return 1;
}
int
efile_symlink(Efile_error* errInfo, char* old, char* new)
{
+ /*
+ * Load dll and see if we have CreateSymbolicLink at runtime:
+ * (Vista only)
+ */
+ HINSTANCE hModule = NULL;
+ if ((hModule = LoadLibrary("kernel32.dll")) != NULL) {
+ typedef BOOLEAN (WINAPI * CREATESYMBOLICLINKFUNCPTR) (
+ LPCSTR lpSymlinkFileName,
+ LPCSTR lpTargetFileName,
+ DWORD dwFlags);
+
+ CREATESYMBOLICLINKFUNCPTR pCreateSymbolicLink =
+ (CREATESYMBOLICLINKFUNCPTR) GetProcAddress(hModule,
+ "CreateSymbolicLinkA");
+ /* A for MBCS, W for UNICODE... char* above implies 'A'! */
+ if (pCreateSymbolicLink != NULL) {
+ DWORD attr = GetFileAttributes(old);
+ int flag = (attr != INVALID_FILE_ATTRIBUTES &&
+ attr & FILE_ATTRIBUTE_DIRECTORY) ? 1 : 0;
+ /* SYMBOLIC_LINK_FLAG_DIRECTORY = 1 */
+ BOOLEAN success = pCreateSymbolicLink(new, old, flag);
+ FreeLibrary(hModule);
+
+ if (success) {
+ return 1;
+ } else {
+ return set_error(errInfo);
+ }
+ } else
+ FreeLibrary(hModule);
+ }
errno = ENOTSUP;
return check_error(-1, errInfo);
}