/*
* %CopyrightBegin%
*
* Copyright Ericsson 2017-2018. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
#include "erl_nif.h"
#include "config.h"
#include "sys.h"
#include "prim_file_nif.h"
#include <winioctl.h>
#include <windows.h>
#include <strsafe.h>
#include <wchar.h>
#define IS_SLASH(a) ((a) == L'\\' || (a) == L'/')
#define FILE_SHARE_FLAGS (FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE)
#define LP_PREFIX L"\\\\?\\"
#define LP_PREFIX_SIZE (sizeof(LP_PREFIX) - sizeof(WCHAR))
#define LP_PREFIX_LENGTH (LP_PREFIX_SIZE / sizeof(WCHAR))
#define PATH_LENGTH(path) (path->size / sizeof(WCHAR) - 1)
#define ASSERT_PATH_FORMAT(path) \
do { \
ASSERT(PATH_LENGTH(path) >= 4 && \
!memcmp(path->data, LP_PREFIX, LP_PREFIX_SIZE)); \
ASSERT(PATH_LENGTH(path) == wcslen((WCHAR*)path->data)); \
} while(0)
#define TICKS_PER_SECOND (10000000ULL)
#define EPOCH_DIFFERENCE (11644473600LL)
#define FILETIME_TO_EPOCH(epoch, ft) \
do { \
ULARGE_INTEGER ull; \
ull.LowPart = (ft).dwLowDateTime; \
ull.HighPart = (ft).dwHighDateTime; \
(epoch) = ((ull.QuadPart / TICKS_PER_SECOND) - EPOCH_DIFFERENCE); \
} while(0)
#define EPOCH_TO_FILETIME(ft, epoch) \
do { \
ULARGE_INTEGER ull; \
ull.QuadPart = (((epoch) + EPOCH_DIFFERENCE) * TICKS_PER_SECOND); \
(ft).dwLowDateTime = ull.LowPart; \
(ft).dwHighDateTime = ull.HighPart; \
} while(0)
typedef struct {
efile_data_t common;
HANDLE handle;
} efile_win_t;
static int windows_to_posix_errno(DWORD last_error);
static int has_invalid_null_termination(const ErlNifBinary *path) {
const WCHAR *null_pos, *end_pos;
null_pos = wmemchr((const WCHAR*)path->data, L'\0', path->size);
end_pos = (const WCHAR*)&path->data[path->size] - 1;
if(null_pos == NULL) {
return 1;
}
/* prim_file:internal_name2native sometimes feeds us data that is "doubly"
* NUL-terminated, so we'll accept any number of trailing NULs so long as
* they aren't interrupted by anything else. */
while(null_pos < end_pos && (*null_pos) == L'\0') {
null_pos++;
}
return null_pos != end_pos;
}
static posix_errno_t get_full_path(ErlNifEnv *env, WCHAR *input, efile_path_t *result) {
DWORD maximum_length, actual_length;
int add_long_prefix;
maximum_length = GetFullPathNameW(input, 0, NULL, NULL);
add_long_prefix = 0;
if(maximum_length == 0) {
/* POSIX doesn't have the concept of a "path error" in the same way
* Windows does, so we'll return ENOENT since that's what most POSIX
* APIs would return if they were fed such garbage. */
return ENOENT;
}
maximum_length += LP_PREFIX_LENGTH;
if(!enif_alloc_binary(maximum_length * sizeof(WCHAR), result)) {
return ENOMEM;
}
actual_length = GetFullPathNameW(input, maximum_length, (WCHAR*)result->data, NULL);
if(actual_length < maximum_length) {
int has_long_path_prefix;
WCHAR *path_start;
/* Make sure we have a long-path prefix; GetFullPathNameW only adds one
* if the path is relative. */
has_long_path_prefix = actual_length >= LP_PREFIX_LENGTH &&
!sys_memcmp(result->data, LP_PREFIX, LP_PREFIX_SIZE);
if(!has_long_path_prefix) {
sys_memmove(result->data + LP_PREFIX_SIZE, result->data,
(actual_length + 1) * sizeof(WCHAR));
sys_memcpy(result->data, LP_PREFIX, LP_PREFIX_SIZE);
actual_length += LP_PREFIX_LENGTH;
}
path_start = (WCHAR*)result->data;
/* We're removing trailing slashes since quite a few APIs refuse to
* work with them, and none require them. We only check the last
* character since GetFullPathNameW folds slashes together. */
if(IS_SLASH(path_start[actual_length - 1])) {
if(path_start[actual_length - 2] != L':') {
path_start[actual_length - 1] = L'\0';
actual_length--;
}
}
if(!enif_realloc_binary(result, (actual_length + 1) * sizeof(WCHAR))) {
enif_release_binary(result);
return ENOMEM;
}
enif_make_binary(env, result);
return 0;
}
/* We may end up here if the current directory changes to something longer
* between/during GetFullPathName. There's nothing sensible we can do about
* this. */
enif_release_binary(result);
return EINVAL;
}
posix_errno_t efile_marshal_path(ErlNifEnv *env, ERL_NIF_TERM path, efile_path_t *result) {
ErlNifBinary raw_path;
if(!enif_inspect_binary(env, path, &raw_path)) {
return EINVAL;
} else if(raw_path.size % sizeof(WCHAR)) {
return EINVAL;
}
if(has_invalid_null_termination(&raw_path)) {
return EINVAL;
}
return get_full_path(env, (WCHAR*)raw_path.data, result);
}
ERL_NIF_TERM efile_get_handle(ErlNifEnv *env, efile_data_t *d) {
efile_win_t *w = (efile_win_t*)d;
ERL_NIF_TERM result;
unsigned char *bits;
bits = enif_make_new_binary(env, sizeof(w->handle), &result);
memcpy(bits, &w->handle, sizeof(w->handle));
return result;
}
/** @brief Converts a native path to the preferred form in "erlang space,"
* without path-prefixes, forward-slashes, or NUL terminators. */
static int normalize_path_result(ErlNifBinary *path) {
WCHAR *path_iterator, *path_start, *path_end;
int length;
path_start = (WCHAR*)path->data;
length = wcslen(path_start);
ASSERT(length < path->size / sizeof(WCHAR));
/* Get rid of the long-path prefix, if present. */
if(length >= LP_PREFIX_LENGTH) {
if(!sys_memcmp(path_start, LP_PREFIX, LP_PREFIX_SIZE)) {
length -= LP_PREFIX_LENGTH;
sys_memmove(path_start, &path_start[LP_PREFIX_LENGTH],
length * sizeof(WCHAR));
}
}
path_end = &path_start[length];
path_iterator = path_start;
/* Convert drive letters to lowercase, if present. */
if(length >= 2 && path_start[1] == L':') {
WCHAR drive_letter = path_start[0];
if(drive_letter >= L'A' && drive_letter <= L'Z') {
path_start[0] = drive_letter - L'A' + L'a';
}
}
while(path_iterator < path_end) {
if(*path_iterator == L'\\') {
*path_iterator = L'/';
}
path_iterator++;
}
/* Truncate the result to its actual length; we don't want to include the
* NUL terminator. */
return enif_realloc_binary(path, length * sizeof(WCHAR));
}
/* @brief Checks whether all the given attributes are set on the object at the
* given path. Note that it assumes false on errors. */
static int has_file_attributes(const efile_path_t *path, DWORD mask) {
DWORD attributes = GetFileAttributesW((WCHAR*)path->data);
if(attributes == INVALID_FILE_ATTRIBUTES) {
return 0;
}
return !!((attributes & mask) == mask);
}
static int is_ignored_name(int name_length, const WCHAR *name) {
if(name_length == 1 && name[0] == L'.') {
return 1;
} else if(name_length == 2 && !sys_memcmp(name, L"..", 2 * sizeof(WCHAR))) {
return 1;
}
return 0;
}
static int get_drive_number(const efile_path_t *path) {
const WCHAR *path_start;
int length;
ASSERT_PATH_FORMAT(path);
path_start = (WCHAR*)path->data + LP_PREFIX_LENGTH;
length = PATH_LENGTH(path) - LP_PREFIX_LENGTH;
if(length >= 2 && path_start[1] == L':') {
WCHAR drive_letter = path_start[0];
if(drive_letter >= L'A' && drive_letter <= L'Z') {
return drive_letter - L'A' + 1;
} else if(drive_letter >= L'a' && drive_letter <= L'z') {
return drive_letter - L'a' + 1;
}
}
return -1;
}
/* @brief Checks whether two *paths* are on the same mount point; they don't
* have to refer to existing or accessible files/directories. */
static int has_same_mount_point(const efile_path_t *path_a, const efile_path_t *path_b) {
WCHAR *mount_a, *mount_b;
int result = 0;
mount_a = enif_alloc(path_a->size);
mount_b = enif_alloc(path_b->size);
if(mount_a != NULL && mount_b != NULL) {
int length_a, length_b;
length_a = PATH_LENGTH(path_a);
length_b = PATH_LENGTH(path_b);
if(GetVolumePathNameW((WCHAR*)path_a->data, mount_a, length_a)) {
ASSERT(wcslen(mount_a) <= length_a);
if(GetVolumePathNameW((WCHAR*)path_b->data, mount_b, length_b)) {
ASSERT(wcslen(mount_b) <= length_b);
result = !_wcsicmp(mount_a, mount_b);
}
}
}
if(mount_b != NULL) {
enif_free(mount_b);
}
if(mount_a != NULL) {
enif_free(mount_a);
}
return result;
}
/* Mirrors the PathIsRootW function of the shell API, but doesn't choke on
* paths longer than MAX_PATH. */
static int is_path_root(const efile_path_t *path) {
const WCHAR *path_start, *path_end;
int length;
ASSERT_PATH_FORMAT(path);
path_start = (WCHAR*)path->data + LP_PREFIX_LENGTH;
length = PATH_LENGTH(path) - LP_PREFIX_LENGTH;
path_end = &path_start[length];
if(length == 1) {
/* A single \ refers to the root of the current working directory. */
return IS_SLASH(path_start[0]);
} else if(length == 3 && iswalpha(path_start[0]) && path_start[1] == L':') {
/* Drive letter. */
return IS_SLASH(path_start[2]);
} else if(length >= 4) {
/* Check whether we're a UNC root, eg. \\server, \\server\share */
const WCHAR *path_iterator;
if(!IS_SLASH(path_start[0]) || !IS_SLASH(path_start[1])) {
return 0;
}
path_iterator = path_start + 2;
/* Slide to the slash between the server and share names, if present. */
while(path_iterator < path_end && !IS_SLASH(*path_iterator)) {
path_iterator++;
}
/* Slide past the end of the string, stopping at the first slash we
* encounter. */
do {
path_iterator++;
} while(path_iterator < path_end && !IS_SLASH(*path_iterator));
/* If we're past the end of the string and it didnt't end with a slash,
* then we're a root path. */
return path_iterator >= path_end && !IS_SLASH(path_start[length - 1]);
}
return 0;
}
posix_errno_t efile_open(const efile_path_t *path, enum efile_modes_t modes,
ErlNifResourceType *nif_type, efile_data_t **d) {
DWORD attributes, access_flags, open_mode;
HANDLE handle;
ASSERT_PATH_FORMAT(path);
access_flags = 0;
open_mode = 0;
if(modes & EFILE_MODE_READ && !(modes & EFILE_MODE_WRITE)) {
access_flags = GENERIC_READ;
open_mode = OPEN_EXISTING;
} else if(modes & EFILE_MODE_WRITE && !(modes & EFILE_MODE_READ)) {
access_flags = GENERIC_WRITE;
open_mode = CREATE_ALWAYS;
} else if(modes & EFILE_MODE_READ_WRITE) {
access_flags = GENERIC_READ | GENERIC_WRITE;
open_mode = OPEN_ALWAYS;
} else {
return EINVAL;
}
if(modes & EFILE_MODE_APPEND) {
access_flags |= FILE_APPEND_DATA;
open_mode = OPEN_ALWAYS;
}
if(modes & EFILE_MODE_EXCLUSIVE) {
open_mode = CREATE_NEW;
}
if(modes & EFILE_MODE_SYNC) {
attributes = FILE_FLAG_WRITE_THROUGH;
} else {
attributes = FILE_ATTRIBUTE_NORMAL;
}
handle = CreateFileW((WCHAR*)path->data, access_flags,
FILE_SHARE_FLAGS, NULL, open_mode, attributes, NULL);
if(handle != INVALID_HANDLE_VALUE) {
efile_win_t *w;
w = (efile_win_t*)enif_alloc_resource(nif_type, sizeof(efile_win_t));
w->handle = handle;
EFILE_INIT_RESOURCE(&w->common, modes);
(*d) = &w->common;
return 0;
} else {
DWORD last_error = GetLastError();
/* Rewrite all failures on directories to EISDIR to match the old
* driver. */
if(has_file_attributes(path, FILE_ATTRIBUTE_DIRECTORY)) {
return EISDIR;
}
return windows_to_posix_errno(last_error);
}
}
int efile_close(efile_data_t *d) {
efile_win_t *w = (efile_win_t*)d;
HANDLE handle;
ASSERT(erts_atomic32_read_nob(&d->state) == EFILE_STATE_CLOSED);
ASSERT(w->handle != INVALID_HANDLE_VALUE);
handle = w->handle;
w->handle = INVALID_HANDLE_VALUE;
if(!CloseHandle(handle)) {
w->common.posix_errno = windows_to_posix_errno(GetLastError());
return 0;
}
return 1;
}
static void shift_overlapped(OVERLAPPED *overlapped, DWORD shift) {
LARGE_INTEGER offset;
ASSERT(shift >= 0);
offset.HighPart = overlapped->OffsetHigh;
offset.LowPart = overlapped->Offset;
/* ~(Uint64)0 is a magic value ("append to end of file") which needs to be
* preserved. Other positions resulting in overflow would have errored out
* just prior to this point. */
if(offset.QuadPart != ERTS_UINT64_MAX) {
offset.QuadPart += shift;
}
/* All unused fields must be zeroed for the next call. */
sys_memset(overlapped, 0, sizeof(*overlapped));
overlapped->OffsetHigh = offset.HighPart;
overlapped->Offset = offset.LowPart;
}
static void shift_iov(SysIOVec **iov, int *iovlen, DWORD shift) {
SysIOVec *head_vec = (*iov);
ASSERT(shift >= 0);
while(shift > 0) {
ASSERT(head_vec < &(*iov)[*iovlen]);
if(shift < head_vec->iov_len) {
head_vec->iov_base = (char*)head_vec->iov_base + shift;
head_vec->iov_len -= shift;
break;
} else {
shift -= head_vec->iov_len;
head_vec++;
}
}
(*iovlen) -= head_vec - (*iov);
(*iov) = head_vec;
}
typedef BOOL (WINAPI *io_op_t)(HANDLE, LPVOID, DWORD, LPDWORD, LPOVERLAPPED);
static Sint64 internal_sync_io(efile_win_t *w, io_op_t operation,
SysIOVec *iov, int iovlen, OVERLAPPED *overlapped) {
Sint64 bytes_processed = 0;
for(;;) {
DWORD block_bytes_processed, last_error;
BOOL succeeded;
if(iovlen < 1) {
return bytes_processed;
}
succeeded = operation(w->handle, iov->iov_base, iov->iov_len,
&block_bytes_processed, overlapped);
last_error = GetLastError();
if(!succeeded && (last_error != ERROR_HANDLE_EOF)) {
w->common.posix_errno = windows_to_posix_errno(last_error);
return -1;
} else if(block_bytes_processed == 0) {
/* EOF */
return bytes_processed;
}
if(overlapped != NULL) {
shift_overlapped(overlapped, block_bytes_processed);
}
shift_iov(&iov, &iovlen, block_bytes_processed);
bytes_processed += block_bytes_processed;
}
}
Sint64 efile_readv(efile_data_t *d, SysIOVec *iov, int iovlen) {
efile_win_t *w = (efile_win_t*)d;
return internal_sync_io(w, ReadFile, iov, iovlen, NULL);
}
Sint64 efile_writev(efile_data_t *d, SysIOVec *iov, int iovlen) {
efile_win_t *w = (efile_win_t*)d;
OVERLAPPED __overlapped, *overlapped;
Uint64 bytes_written;
if(w->common.modes & EFILE_MODE_APPEND) {
overlapped = &__overlapped;
sys_memset(overlapped, 0, sizeof(*overlapped));
overlapped->OffsetHigh = 0xFFFFFFFF;
overlapped->Offset = 0xFFFFFFFF;
} else {
overlapped = NULL;
}
return internal_sync_io(w, WriteFile, iov, iovlen, overlapped);
}
Sint64 efile_preadv(efile_data_t *d, Sint64 offset, SysIOVec *iov, int iovlen) {
efile_win_t *w = (efile_win_t*)d;
OVERLAPPED overlapped;
sys_memset(&overlapped, 0, sizeof(overlapped));
overlapped.OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
overlapped.Offset = offset & 0xFFFFFFFF;
return internal_sync_io(w, ReadFile, iov, iovlen, &overlapped);
}
Sint64 efile_pwritev(efile_data_t *d, Sint64 offset, SysIOVec *iov, int iovlen) {
efile_win_t *w = (efile_win_t*)d;
OVERLAPPED overlapped;
sys_memset(&overlapped, 0, sizeof(overlapped));
overlapped.OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
overlapped.Offset = offset & 0xFFFFFFFF;
return internal_sync_io(w, WriteFile, iov, iovlen, &overlapped);
}
int efile_seek(efile_data_t *d, enum efile_seek_t seek, Sint64 offset, Sint64 *new_position) {
efile_win_t *w = (efile_win_t*)d;
LARGE_INTEGER large_offset, large_new_position;
DWORD whence;
switch(seek) {
case EFILE_SEEK_BOF: whence = FILE_BEGIN; break;
case EFILE_SEEK_CUR: whence = FILE_CURRENT; break;
case EFILE_SEEK_EOF: whence = FILE_END; break;
default: ERTS_INTERNAL_ERROR("Invalid seek parameter");
}
large_offset.QuadPart = offset;
if(!SetFilePointerEx(w->handle, large_offset, &large_new_position, whence)) {
w->common.posix_errno = windows_to_posix_errno(GetLastError());
return 0;
}
(*new_position) = large_new_position.QuadPart;
return 1;
}
int efile_sync(efile_data_t *d, int data_only) {
efile_win_t *w = (efile_win_t*)d;
/* Windows doesn't support data-only syncing. */
(void)data_only;
if(!FlushFileBuffers(w->handle)) {
w->common.posix_errno = windows_to_posix_errno(GetLastError());
return 0;
}
return 1;
}
int efile_advise(efile_data_t *d, Sint64 offset, Sint64 length, enum efile_advise_t advise) {
/* Windows doesn't support this, but we'll pretend it does since the call
* is only a recommendation even on systems that do support it. */
(void)d;
(void)offset;
(void)length;
(void)advise;
return 1;
}
int efile_allocate(efile_data_t *d, Sint64 offset, Sint64 length) {
efile_win_t *w = (efile_win_t*)d;
(void)d;
(void)offset;
(void)length;
w->common.posix_errno = ENOTSUP;
return 0;
}
int efile_truncate(efile_data_t *d) {
efile_win_t *w = (efile_win_t*)d;
if(!SetEndOfFile(w->handle)) {
w->common.posix_errno = windows_to_posix_errno(GetLastError());
return 0;
}
return 1;
}
static int is_executable_file(const efile_path_t *path) {
/* We're using the file extension in order to be quirks-compliant with the
* old driver, which never bothered to check the actual permissions. We
* could easily do so now (cf. GetNamedSecurityInfo) but the execute
* permission is only relevant for files that are started with the default
* loader, and batch files run just fine with read permission alone. */
int length = PATH_LENGTH(path);
if(length >= 4) {
const WCHAR *last_four = &((WCHAR*)path->data)[length - 4];
if (!_wcsicmp(last_four, L".exe") ||
!_wcsicmp(last_four, L".cmd") ||
!_wcsicmp(last_four, L".bat") ||
!_wcsicmp(last_four, L".com")) {
return 1;
}
}
return 0;
}
/* Returns whether the path refers to a link-like object, e.g. a junction
* point, symbolic link, or mounted folder. */
static int is_name_surrogate(const efile_path_t *path) {
HANDLE handle;
int result;
handle = CreateFileW((const WCHAR*)path->data, GENERIC_READ,
FILE_SHARE_FLAGS, NULL, OPEN_EXISTING,
FILE_FLAG_OPEN_REPARSE_POINT |
FILE_FLAG_BACKUP_SEMANTICS,
NULL);
result = 0;
if(handle != INVALID_HANDLE_VALUE) {
REPARSE_GUID_DATA_BUFFER reparse_buffer;
DWORD unused_length;
BOOL success;
success = DeviceIoControl(handle,
FSCTL_GET_REPARSE_POINT, NULL, 0,
&reparse_buffer, sizeof(reparse_buffer),
&unused_length, NULL);
/* ERROR_MORE_DATA is tolerated since we're guaranteed to have filled
* the field we want. */
if(success || GetLastError() == ERROR_MORE_DATA) {
result = IsReparseTagNameSurrogate(reparse_buffer.ReparseTag);
}
CloseHandle(handle);
}
return result;
}
posix_errno_t efile_read_info(const efile_path_t *path, int follow_links, efile_fileinfo_t *result) {
BY_HANDLE_FILE_INFORMATION native_file_info;
DWORD attributes;
int is_link;
sys_memset(&native_file_info, 0, sizeof(native_file_info));
is_link = 0;
attributes = GetFileAttributesW((WCHAR*)path->data);
if(attributes == INVALID_FILE_ATTRIBUTES) {
DWORD last_error = GetLastError();
/* Querying a network share root fails with ERROR_BAD_NETPATH, so we'll
* fake it as a directory just like local roots. */
if(!is_path_root(path) || last_error != ERROR_BAD_NETPATH) {
return windows_to_posix_errno(last_error);
}
attributes = FILE_ATTRIBUTE_DIRECTORY;
} else if(is_path_root(path)) {
/* Local (or mounted) roots can be queried with GetFileAttributesW but
* lack support for GetFileInformationByHandle, so we'll skip that
* part. */
} else {
HANDLE handle;
if(attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
is_link = is_name_surrogate(path);
}
if(follow_links && is_link) {
posix_errno_t posix_errno;
efile_path_t resolved_path;
posix_errno = internal_read_link(path, &resolved_path);
if(posix_errno != 0) {
return posix_errno;
}
return efile_read_info(&resolved_path, 0, result);
}
handle = CreateFileW((const WCHAR*)path->data, GENERIC_READ,
FILE_SHARE_FLAGS, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS,
NULL);
/* The old driver never cared whether this succeeded. */
if(handle != INVALID_HANDLE_VALUE) {
GetFileInformationByHandle(handle, &native_file_info);
CloseHandle(handle);
}
FILETIME_TO_EPOCH(result->m_time, native_file_info.ftLastWriteTime);
FILETIME_TO_EPOCH(result->a_time, native_file_info.ftLastAccessTime);
FILETIME_TO_EPOCH(result->c_time, native_file_info.ftCreationTime);
if(result->m_time == -EPOCH_DIFFERENCE) {
/* Default to 1970 just like the old driver. */
result->m_time = 0;
}
if(result->a_time == -EPOCH_DIFFERENCE) {
result->a_time = result->m_time;
}
if(result->c_time == -EPOCH_DIFFERENCE) {
result->c_time = result->m_time;
}
}
if(is_link) {
result->type = EFILE_FILETYPE_SYMLINK;
/* This should be _S_IFLNK, but the old driver always set
* non-directories to _S_IFREG. */
result->mode |= _S_IFREG;
} else if(attributes & FILE_ATTRIBUTE_DIRECTORY) {
result->type = EFILE_FILETYPE_DIRECTORY;
result->mode |= _S_IFDIR | _S_IEXEC;
} else {
if(is_executable_file(path)) {
result->mode |= _S_IEXEC;
}
result->type = EFILE_FILETYPE_REGULAR;
result->mode |= _S_IFREG;
}
if(!(attributes & FILE_ATTRIBUTE_READONLY)) {
result->access = EFILE_ACCESS_READ | EFILE_ACCESS_WRITE;
result->mode |= _S_IREAD | _S_IWRITE;
} else {
result->access = EFILE_ACCESS_READ;
result->mode |= _S_IREAD;
}
/* Propagate user mode-bits to group/other fields */
result->mode |= (result->mode & 0700) >> 3;
result->mode |= (result->mode & 0700) >> 6;
result->size =
((Uint64)native_file_info.nFileSizeHigh << 32ull) |
(Uint64)native_file_info.nFileSizeLow;
result->links = MAX(1, native_file_info.nNumberOfLinks);
result->major_device = get_drive_number(path);
result->minor_device = 0;
result->inode = 0;
result->uid = 0;
result->gid = 0;
return 0;
}
posix_errno_t efile_set_permissions(const efile_path_t *path, Uint32 permissions) {
DWORD attributes = GetFileAttributesW((WCHAR*)path->data);
if(attributes == INVALID_FILE_ATTRIBUTES) {
return windows_to_posix_errno(GetLastError());
}
if(permissions & _S_IWRITE) {
attributes &= ~FILE_ATTRIBUTE_READONLY;
} else {
attributes |= FILE_ATTRIBUTE_READONLY;
}
if(SetFileAttributesW((WCHAR*)path->data, attributes)) {
return 0;
}
return windows_to_posix_errno(GetLastError());
}
posix_errno_t efile_set_owner(const efile_path_t *path, Sint32 owner, Sint32 group) {
(void)path;
(void)owner;
(void)group;
return 0;
}
posix_errno_t efile_set_time(const efile_path_t *path, Sint64 a_time, Sint64 m_time, Sint64 c_time) {
FILETIME accessed, modified, created;
DWORD last_error, attributes;
HANDLE handle;
attributes = GetFileAttributesW((WCHAR*)path->data);
if(attributes == INVALID_FILE_ATTRIBUTES) {
return windows_to_posix_errno(GetLastError());
}
/* If the file is read-only, we have to make it temporarily writable while
* setting new metadata. */
if(attributes & FILE_ATTRIBUTE_READONLY) {
DWORD without_readonly = attributes & ~FILE_ATTRIBUTE_READONLY;
if(!SetFileAttributesW((WCHAR*)path->data, without_readonly)) {
return windows_to_posix_errno(GetLastError());
}
}
EPOCH_TO_FILETIME(modified, m_time);
EPOCH_TO_FILETIME(accessed, a_time);
EPOCH_TO_FILETIME(created, c_time);
handle = CreateFileW((WCHAR*)path->data, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_FLAGS, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
last_error = GetLastError();
if(handle != INVALID_HANDLE_VALUE) {
if(SetFileTime(handle, &created, &accessed, &modified)) {
last_error = ERROR_SUCCESS;
} else {
last_error = GetLastError();
}
CloseHandle(handle);
}
if(attributes & FILE_ATTRIBUTE_READONLY) {
SetFileAttributesW((WCHAR*)path->data, attributes);
}
return windows_to_posix_errno(last_error);
}
static posix_errno_t internal_read_link(const efile_path_t *path, efile_path_t *result) {
DWORD required_length, actual_length;
HANDLE link_handle;
DWORD last_error;
link_handle = CreateFileW((WCHAR*)path->data, GENERIC_READ,
FILE_SHARE_FLAGS, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
last_error = GetLastError();
if(link_handle == INVALID_HANDLE_VALUE) {
return windows_to_posix_errno(last_error);
}
required_length = GetFinalPathNameByHandleW(link_handle, NULL, 0, 0);
last_error = GetLastError();
if(required_length <= 0) {
CloseHandle(link_handle);
return windows_to_posix_errno(last_error);
}
/* Unlike many other path functions (eg. GetFullPathNameW), this one
* includes the NUL terminator in its required length. */
if(!enif_alloc_binary(required_length * sizeof(WCHAR), result)) {
CloseHandle(link_handle);
return ENOMEM;
}
actual_length = GetFinalPathNameByHandleW(link_handle,
(WCHAR*)result->data, required_length, 0);
last_error = GetLastError();
CloseHandle(link_handle);
if(actual_length == 0 || actual_length >= required_length) {
enif_release_binary(result);
return windows_to_posix_errno(last_error);
}
/* GetFinalPathNameByHandle always prepends with "\\?\" and NUL-terminates,
* so we never have to touch-up the resulting path. */
ASSERT_PATH_FORMAT(result);
return 0;
}
posix_errno_t efile_read_link(ErlNifEnv *env, const efile_path_t *path, ERL_NIF_TERM *result) {
posix_errno_t posix_errno;
ErlNifBinary result_bin;
DWORD attributes;
ASSERT_PATH_FORMAT(path);
attributes = GetFileAttributesW((WCHAR*)path->data);
if(attributes == INVALID_FILE_ATTRIBUTES) {
return windows_to_posix_errno(GetLastError());
} else if(!(attributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
return EINVAL;
}
if(!is_name_surrogate(path)) {
return EINVAL;
}
posix_errno = internal_read_link(path, &result_bin);
if(posix_errno == 0) {
if(!normalize_path_result(&result_bin)) {
enif_release_binary(&result_bin);
return ENOMEM;
}
(*result) = enif_make_binary(env, &result_bin);
}
return posix_errno;
}
posix_errno_t efile_list_dir(ErlNifEnv *env, const efile_path_t *path, ERL_NIF_TERM *result) {
ERL_NIF_TERM list_head;
WIN32_FIND_DATAW data;
HANDLE search_handle;
WCHAR *search_path;
DWORD last_error;
ASSERT_PATH_FORMAT(path);
search_path = enif_alloc(path->size + 2 * sizeof(WCHAR));
if(search_path == NULL) {
return ENOMEM;
}
sys_memcpy(search_path, path->data, path->size);
search_path[PATH_LENGTH(path) + 0] = L'\\';
search_path[PATH_LENGTH(path) + 1] = L'*';
search_path[PATH_LENGTH(path) + 2] = L'\0';
search_handle = FindFirstFileW(search_path, &data);
last_error = GetLastError();
enif_free(search_path);
if(search_handle == INVALID_HANDLE_VALUE) {
return windows_to_posix_errno(last_error);
}
list_head = enif_make_list(env, 0);
do {
int name_length = wcslen(data.cFileName);
if(!is_ignored_name(name_length, data.cFileName)) {
unsigned char *name_bytes;
ERL_NIF_TERM name_term;
size_t name_size;
name_size = name_length * sizeof(WCHAR);
name_bytes = enif_make_new_binary(env, name_size, &name_term);
sys_memcpy(name_bytes, data.cFileName, name_size);
list_head = enif_make_list_cell(env, name_term, list_head);
}
} while(FindNextFileW(search_handle, &data));
FindClose(search_handle);
(*result) = list_head;
return 0;
}
posix_errno_t efile_rename(const efile_path_t *old_path, const efile_path_t *new_path) {
BOOL old_is_directory, new_is_directory;
DWORD move_flags, last_error;
ASSERT_PATH_FORMAT(old_path);
ASSERT_PATH_FORMAT(new_path);
move_flags = MOVEFILE_COPY_ALLOWED | MOVEFILE_WRITE_THROUGH;
if(MoveFileExW((WCHAR*)old_path->data, (WCHAR*)new_path->data, move_flags)) {
return 0;
}
last_error = GetLastError();
old_is_directory = has_file_attributes(old_path, FILE_ATTRIBUTE_DIRECTORY);
new_is_directory = has_file_attributes(new_path, FILE_ATTRIBUTE_DIRECTORY);
switch(last_error) {
case ERROR_SHARING_VIOLATION:
case ERROR_ACCESS_DENIED:
if(old_is_directory) {
BOOL moved_into_itself;
moved_into_itself = (old_path->size <= new_path->size) &&
!_wcsnicmp((WCHAR*)old_path->data, (WCHAR*)new_path->data,
PATH_LENGTH(old_path));
if(moved_into_itself) {
return EINVAL;
} else if(is_path_root(old_path)) {
return EINVAL;
}
/* Renaming a directory across volumes needs to be rewritten as
* EXDEV so that the caller can respond by simulating it with
* copy/delete operations.
*
* Files are handled through MOVEFILE_COPY_ALLOWED. */
if(!has_same_mount_point(old_path, new_path)) {
return EXDEV;
}
}
break;
case ERROR_PATH_NOT_FOUND:
case ERROR_FILE_NOT_FOUND:
return ENOENT;
case ERROR_ALREADY_EXISTS:
case ERROR_FILE_EXISTS:
if(old_is_directory && !new_is_directory) {
return ENOTDIR;
} else if(!old_is_directory && new_is_directory) {
return EISDIR;
} else if(old_is_directory && new_is_directory) {
/* This will fail if the destination isn't empty. */
if(RemoveDirectoryW((WCHAR*)new_path->data)) {
return efile_rename(old_path, new_path);
}
return EEXIST;
} else if(!old_is_directory && !new_is_directory) {
/* This is pretty iffy; the public documentation says that the
* operation may EACCES on some systems when either file is open,
* which gives us room to use MOVEFILE_REPLACE_EXISTING and be done
* with it, but the old implementation simulated Unix semantics and
* there's a lot of code that relies on that.
*
* The simulation renames the destination to a scratch name to get
* around the fact that it's impossible to open (and by extension
* rename) a file that's been deleted while open. It has a few
* drawbacks though;
*
* 1) It's not atomic as there's a small window where there's no
* file at all on the destination path.
* 2) It will confuse applications that subscribe to folder
* changes.
* 3) It will fail if we lack general permission to write in the
* same folder. */
WCHAR *swap_path = enif_alloc(new_path->size + sizeof(WCHAR) * 64);
if(swap_path == NULL) {
return ENOMEM;
} else {
static LONGLONG unique_counter = 0;
WCHAR *swap_path_end;
/* We swap in the same folder as the destination to be
* reasonably sure that it's on the same volume. Note that
* we're avoiding GetTempFileNameW as it will fail on long
* paths. */
sys_memcpy(swap_path, (WCHAR*)new_path->data, new_path->size);
swap_path_end = swap_path + PATH_LENGTH(new_path);
while(!IS_SLASH(*swap_path_end)) {
ASSERT(swap_path_end > swap_path);
swap_path_end--;
}
StringCchPrintfW(&swap_path_end[1], 64, L"erl-%lx-%llx.tmp",
GetCurrentProcessId(), unique_counter);
InterlockedIncrement64(&unique_counter);
}
if(MoveFileExW((WCHAR*)new_path->data, swap_path, MOVEFILE_REPLACE_EXISTING)) {
if(MoveFileExW((WCHAR*)old_path->data, (WCHAR*)new_path->data, move_flags)) {
last_error = ERROR_SUCCESS;
DeleteFileW(swap_path);
} else {
last_error = GetLastError();
MoveFileW(swap_path, (WCHAR*)new_path->data);
}
} else {
last_error = GetLastError();
DeleteFileW(swap_path);
}
enif_free(swap_path);
return windows_to_posix_errno(last_error);
}
return EEXIST;
}
return windows_to_posix_errno(last_error);
}
posix_errno_t efile_make_hard_link(const efile_path_t *existing_path, const efile_path_t *new_path) {
ASSERT_PATH_FORMAT(existing_path);
ASSERT_PATH_FORMAT(new_path);
if(!CreateHardLinkW((WCHAR*)new_path->data, (WCHAR*)existing_path->data, NULL)) {
return windows_to_posix_errno(GetLastError());
}
return 0;
}
posix_errno_t efile_make_soft_link(const efile_path_t *existing_path, const efile_path_t *new_path) {
DWORD link_flags;
ASSERT_PATH_FORMAT(existing_path);
ASSERT_PATH_FORMAT(new_path);
if(has_file_attributes(existing_path, FILE_ATTRIBUTE_DIRECTORY)) {
link_flags = SYMBOLIC_LINK_FLAG_DIRECTORY;
} else {
link_flags = 0;
}
if(!CreateSymbolicLinkW((WCHAR*)new_path->data, (WCHAR*)existing_path->data, link_flags)) {
return windows_to_posix_errno(GetLastError());
}
return 0;
}
posix_errno_t efile_make_dir(const efile_path_t *path) {
ASSERT_PATH_FORMAT(path);
if(!CreateDirectoryW((WCHAR*)path->data, NULL)) {
return windows_to_posix_errno(GetLastError());
}
return 0;
}
posix_errno_t efile_del_file(const efile_path_t *path) {
ASSERT_PATH_FORMAT(path);
if(!DeleteFileW((WCHAR*)path->data)) {
DWORD last_error = GetLastError();
switch(last_error) {
case ERROR_INVALID_NAME:
/* Attempted to delete a device or similar. */
return EACCES;
case ERROR_ACCESS_DENIED:
/* Windows NT reports removing a directory as EACCES instead of
* EPERM. */
if(has_file_attributes(path, FILE_ATTRIBUTE_DIRECTORY)) {
return EPERM;
}
break;
}
return windows_to_posix_errno(last_error);
}
return 0;
}
posix_errno_t efile_del_dir(const efile_path_t *path) {
ASSERT_PATH_FORMAT(path);
if(!RemoveDirectoryW((WCHAR*)path->data)) {
DWORD last_error = GetLastError();
if(last_error == ERROR_DIRECTORY) {
return ENOTDIR;
}
return windows_to_posix_errno(last_error);
}
return 0;
}
posix_errno_t efile_set_cwd(const efile_path_t *path) {
const WCHAR *path_start;
ASSERT_PATH_FORMAT(path);
/* We have to use _wchdir since that's the only function that updates the
* per-drive working directory, but it naively assumes that all paths
* starting with \\ are UNC paths, so we have to skip the \\?\-prefix. */
path_start = (WCHAR*)path->data + LP_PREFIX_LENGTH;
if(_wchdir(path_start)) {
return windows_to_posix_errno(GetLastError());
}
return 0;
}
static int is_valid_drive(int device_index) {
WCHAR drive_path[4] = {L'?', L':', L'\\', L'\0'};
if(device_index == 0) {
/* Default drive; always valid. */
return 1;
} else if(device_index > (L'Z' - L'A' + 1)) {
return 0;
}
drive_path[0] = device_index + L'A' - 1;
switch(GetDriveTypeW(drive_path)) {
case DRIVE_NO_ROOT_DIR:
case DRIVE_UNKNOWN:
return 0;
}
return 1;
}
posix_errno_t efile_get_device_cwd(ErlNifEnv *env, int device_index, ERL_NIF_TERM *result) {
ErlNifBinary result_bin;
/* _wgetdcwd might crash the entire emulator on debug builds since the CRT
* invalid parameter handler asserts if passed a non-existent drive (Or
* simply one that has been unmounted), so we check it ourselves to avoid
* that. */
if(!is_valid_drive(device_index)) {
return EACCES;
}
if(!enif_alloc_binary(MAX_PATH * sizeof(WCHAR), &result_bin)) {
return ENOMEM;
}
if(_wgetdcwd(device_index, (WCHAR*)result_bin.data, MAX_PATH) == NULL) {
enif_release_binary(&result_bin);
return EACCES;
}
if(!normalize_path_result(&result_bin)) {
enif_release_binary(&result_bin);
return ENOMEM;
}
(*result) = enif_make_binary(env, &result_bin);
return 0;
}
posix_errno_t efile_get_cwd(ErlNifEnv *env, ERL_NIF_TERM *result) {
return efile_get_device_cwd(env, 0, result);
}
posix_errno_t efile_altname(ErlNifEnv *env, const efile_path_t *path, ERL_NIF_TERM *result) {
ErlNifBinary result_bin;
ASSERT_PATH_FORMAT(path);
if(is_path_root(path)) {
/* Root paths can't be queried so we'll just return them as they are. */
if(!enif_alloc_binary(path->size, &result_bin)) {
return ENOMEM;
}
sys_memcpy(result_bin.data, path->data, path->size);
} else {
WIN32_FIND_DATAW data;
HANDLE handle;
WCHAR *name_buffer;
int name_length;
/* Reject path wildcards. */
if(wcspbrk(&((const WCHAR*)path->data)[4], L"?*")) {
return ENOENT;
}
handle = FindFirstFileW((const WCHAR*)path->data, &data);
if(handle == INVALID_HANDLE_VALUE) {
return windows_to_posix_errno(GetLastError());
}
FindClose(handle);
name_length = wcslen(data.cAlternateFileName);
if(name_length > 0) {
name_buffer = data.cAlternateFileName;
} else {
name_length = wcslen(data.cFileName);
name_buffer = data.cFileName;
}
/* Include NUL-terminator; it will be removed after normalization. */
name_length += 1;
if(!enif_alloc_binary(name_length * sizeof(WCHAR), &result_bin)) {
return ENOMEM;
}
sys_memcpy(result_bin.data, name_buffer, name_length * sizeof(WCHAR));
}
if(!normalize_path_result(&result_bin)) {
enif_release_binary(&result_bin);
return ENOMEM;
}
(*result) = enif_make_binary(env, &result_bin);
return 0;
}
static int windows_to_posix_errno(DWORD last_error) {
switch(last_error) {
case ERROR_SUCCESS:
return 0;
case ERROR_INVALID_FUNCTION:
case ERROR_INVALID_DATA:
case ERROR_INVALID_PARAMETER:
case ERROR_INVALID_TARGET_HANDLE:
case ERROR_INVALID_CATEGORY:
case ERROR_NEGATIVE_SEEK:
return EINVAL;
case ERROR_DIR_NOT_EMPTY:
return EEXIST;
case ERROR_BAD_FORMAT:
return ENOEXEC;
case ERROR_PATH_NOT_FOUND:
case ERROR_FILE_NOT_FOUND:
case ERROR_NO_MORE_FILES:
case ERROR_INVALID_NAME:
return ENOENT;
case ERROR_TOO_MANY_OPEN_FILES:
return EMFILE;
case ERROR_ACCESS_DENIED:
case ERROR_INVALID_ACCESS:
case ERROR_CURRENT_DIRECTORY:
case ERROR_SHARING_VIOLATION:
case ERROR_LOCK_VIOLATION:
case ERROR_INVALID_PASSWORD:
case ERROR_DRIVE_LOCKED:
return EACCES;
case ERROR_INVALID_HANDLE:
return EBADF;
case ERROR_NOT_ENOUGH_MEMORY:
case ERROR_OUTOFMEMORY:
case ERROR_OUT_OF_STRUCTURES:
return ENOMEM;
case ERROR_INVALID_DRIVE:
case ERROR_BAD_UNIT:
case ERROR_NOT_READY:
case ERROR_REM_NOT_LIST:
case ERROR_DUP_NAME:
case ERROR_BAD_NETPATH:
case ERROR_NETWORK_BUSY:
case ERROR_DEV_NOT_EXIST:
case ERROR_BAD_NET_NAME:
return ENXIO;
case ERROR_NOT_SAME_DEVICE:
return EXDEV;
case ERROR_WRITE_PROTECT:
return EROFS;
case ERROR_BAD_LENGTH:
case ERROR_BUFFER_OVERFLOW:
return E2BIG;
case ERROR_SEEK:
case ERROR_SECTOR_NOT_FOUND:
return ESPIPE;
case ERROR_NOT_DOS_DISK:
return ENODEV;
case ERROR_GEN_FAILURE:
return ENODEV;
case ERROR_SHARING_BUFFER_EXCEEDED:
case ERROR_NO_MORE_SEARCH_HANDLES:
return EMFILE;
case ERROR_HANDLE_EOF:
case ERROR_BROKEN_PIPE:
return EPIPE;
case ERROR_HANDLE_DISK_FULL:
case ERROR_DISK_FULL:
return ENOSPC;
case ERROR_NOT_SUPPORTED:
return ENOTSUP;
case ERROR_FILE_EXISTS:
case ERROR_ALREADY_EXISTS:
case ERROR_CANNOT_MAKE:
return EEXIST;
case ERROR_ALREADY_ASSIGNED:
return EBUSY;
case ERROR_NO_PROC_SLOTS:
return EAGAIN;
case ERROR_CANT_RESOLVE_FILENAME:
return EMLINK;
case ERROR_PRIVILEGE_NOT_HELD:
return EPERM;
case ERROR_ARENA_TRASHED:
case ERROR_INVALID_BLOCK:
case ERROR_BAD_ENVIRONMENT:
case ERROR_BAD_COMMAND:
case ERROR_CRC:
case ERROR_OUT_OF_PAPER:
case ERROR_READ_FAULT:
case ERROR_WRITE_FAULT:
case ERROR_WRONG_DISK:
case ERROR_NET_WRITE_FAULT:
return EIO;
default: /* not to do with files I expect. */
return EIO;
}
}