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/**************************************************************************/
/* */
/* OCaml */
/* */
/* David Allsopp, MetaStack Solutions Ltd. */
/* */
/* Copyright 2015 MetaStack Solutions Ltd. */
/* */
/* All rights reserved. This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/* */
/**************************************************************************/
#define CAML_INTERNALS
#include <caml/mlvalues.h>
#include <caml/memory.h>
#include <caml/alloc.h>
#include <caml/fail.h>
#include <caml/signals.h>
#include <caml/osdeps.h>
#include "unixsupport.h"
#include <errno.h>
#include <winioctl.h>
#include <caml/winsupport.h>
CAMLprim value caml_unix_readlink(value opath)
{
CAMLparam1(opath);
CAMLlocal1(result);
HANDLE h;
wchar_t* path;
DWORD attributes;
caml_unix_check_path(opath, "readlink");
path = caml_stat_strdup_to_utf16(String_val(opath));
caml_enter_blocking_section();
attributes = GetFileAttributes(path);
caml_leave_blocking_section();
if (attributes == INVALID_FILE_ATTRIBUTES) {
caml_stat_free(path);
caml_win32_maperr(GetLastError());
caml_uerror("readlink", opath);
}
else if (!(attributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
caml_stat_free(path);
errno = EINVAL;
caml_uerror("readlink", opath);
}
else {
caml_enter_blocking_section();
if ((h = CreateFile(path,
FILE_READ_ATTRIBUTES,
FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
NULL)) == INVALID_HANDLE_VALUE) {
caml_leave_blocking_section();
caml_stat_free(path);
errno = ENOENT;
caml_uerror("readlink", opath);
}
else {
char buffer[16384];
DWORD read;
REPARSE_DATA_BUFFER* point;
caml_stat_free(path);
if (DeviceIoControl(h, FSCTL_GET_REPARSE_POINT, NULL, 0, buffer, 16384, &read, NULL)) {
caml_leave_blocking_section();
point = (REPARSE_DATA_BUFFER*)buffer;
if (point->ReparseTag == IO_REPARSE_TAG_SYMLINK) {
int cbLen = point->SymbolicLinkReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
int len;
len =
caml_win32_wide_char_to_multi_byte(
point->SymbolicLinkReparseBuffer.PathBuffer + point->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR),
cbLen, NULL, 0);
result = caml_alloc_string(len);
caml_win32_wide_char_to_multi_byte(
point->SymbolicLinkReparseBuffer.PathBuffer + point->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR),
cbLen,
(char *)String_val(result),
len);
CloseHandle(h);
}
else {
errno = EINVAL;
CloseHandle(h);
caml_uerror("readlink", opath);
}
}
else {
caml_leave_blocking_section();
caml_win32_maperr(GetLastError());
CloseHandle(h);
caml_uerror("readlink", opath);
}
}
}
CAMLreturn(result);
}
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