diff options
Diffstat (limited to 'erts/emulator/nifs/win32')
-rw-r--r-- | erts/emulator/nifs/win32/win_prim_file.c | 1427 |
1 files changed, 1427 insertions, 0 deletions
diff --git a/erts/emulator/nifs/win32/win_prim_file.c b/erts/emulator/nifs/win32/win_prim_file.c new file mode 100644 index 0000000000..9f993f1d24 --- /dev/null +++ b/erts/emulator/nifs/win32/win_prim_file.c @@ -0,0 +1,1427 @@ +/* + * %CopyrightBegin% + * + * Copyright Ericsson 2017. 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 <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; +} + +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; + + sys_memset(&native_file_info, 0, sizeof(native_file_info)); + + 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(follow_links && (attributes & FILE_ATTRIBUTE_REPARSE_POINT)) { + 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(attributes & FILE_ATTRIBUTE_REPARSE_POINT) { + 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, Uint32 owner, Uint32 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; + } + + 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: + 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; + } +} |