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authorErlang/OTP <[email protected]>2018-10-12 17:12:04 +0200
committerErlang/OTP <[email protected]>2018-10-12 17:12:04 +0200
commit773d665794a6cfd6a95ef024666980fb68ab9dac (patch)
treefa160ac7900f2cfe8a6cb0390a675a69dea7bda2 /erts
parent2197249f2407e4912d461c627370b9838709d2f2 (diff)
parent1997b6b57d755e25d4050043450bb3cc7b229189 (diff)
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Merge branch 'john/erts/fix-unc-paths-windows/OTP-15333/ERL-737' into maint-21
* john/erts/fix-unc-paths-windows/OTP-15333/ERL-737: erts: Fix UNC path handling on Windows erts: Fix a compiler warning
Diffstat (limited to 'erts')
-rw-r--r--erts/emulator/nifs/win32/win_prim_file.c157
1 files changed, 103 insertions, 54 deletions
diff --git a/erts/emulator/nifs/win32/win_prim_file.c b/erts/emulator/nifs/win32/win_prim_file.c
index f7fae3c637..602a282dd1 100644
--- a/erts/emulator/nifs/win32/win_prim_file.c
+++ b/erts/emulator/nifs/win32/win_prim_file.c
@@ -33,16 +33,32 @@
#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))
+/* Long paths can either be in the file (?) or the device (.) namespace. UNC
+ * paths are always in the file namespace. */
+#define LP_FILE_PREFIX L"\\\\?\\"
+#define LP_DEV_PREFIX L"\\\\.\\"
+#define LP_UNC_PREFIX (LP_FILE_PREFIX L"UNC\\")
+
+#define LP_PREFIX_SIZE (sizeof(LP_FILE_PREFIX) - sizeof(WCHAR))
#define LP_PREFIX_LENGTH (LP_PREFIX_SIZE / sizeof(WCHAR))
+#define LP_UNC_PREFIX_SIZE (sizeof(LP_UNC_PREFIX) - sizeof(WCHAR))
+#define LP_UNC_PREFIX_LENGTH (LP_UNC_PREFIX_SIZE / sizeof(WCHAR))
+
+#define IS_LONG_PATH(length, data) \
+ ((length) >= LP_PREFIX_LENGTH && \
+ (!sys_memcmp((data), LP_FILE_PREFIX, LP_PREFIX_SIZE) || \
+ !sys_memcmp((data), LP_DEV_PREFIX, LP_PREFIX_SIZE)))
+
+#define IS_LONG_UNC_PATH(length, data) \
+ ((length) >= LP_UNC_PREFIX_LENGTH && \
+ !sys_memcmp((data), LP_UNC_PREFIX, LP_UNC_PREFIX_SIZE))
+
#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(IS_LONG_PATH(PATH_LENGTH(path), (path)->data)); \
ASSERT(PATH_LENGTH(path) == wcslen((WCHAR*)path->data)); \
} while(0)
@@ -106,7 +122,7 @@ static posix_errno_t get_full_path(ErlNifEnv *env, WCHAR *input, efile_path_t *r
return ENOENT;
}
- maximum_length += LP_PREFIX_LENGTH;
+ maximum_length += MAX(LP_PREFIX_LENGTH, LP_UNC_PREFIX_LENGTH);
if(!enif_alloc_binary(maximum_length * sizeof(WCHAR), result)) {
return ENOMEM;
@@ -115,18 +131,28 @@ static posix_errno_t get_full_path(ErlNifEnv *env, WCHAR *input, efile_path_t *r
actual_length = GetFullPathNameW(input, maximum_length, (WCHAR*)result->data, NULL);
if(actual_length < maximum_length) {
- int has_long_path_prefix;
+ int is_long_path, maybe_unc_path;
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) {
+ /* The APIs we use have varying path length limits and sometimes
+ * behave differently when given a long-path prefix, so it's simplest
+ * to always use long paths. */
+
+ is_long_path = IS_LONG_PATH(actual_length, result->data);
+ maybe_unc_path = !sys_memcmp(result->data, L"\\\\", sizeof(WCHAR) * 2);
+
+ if(maybe_unc_path && !is_long_path) {
+ /* \\localhost\c$\gurka -> \\?\UNC\localhost\c$\gurka */
+ sys_memmove(result->data + LP_UNC_PREFIX_SIZE,
+ &((WCHAR*)result->data)[2],
+ (actual_length - 1) * sizeof(WCHAR));
+ sys_memcpy(result->data, LP_UNC_PREFIX, LP_UNC_PREFIX_SIZE);
+ actual_length += LP_UNC_PREFIX_LENGTH;
+ } else if(!is_long_path) {
+ /* C:\gurka -> \\?\C:\gurka */
sys_memmove(result->data + LP_PREFIX_SIZE, result->data,
(actual_length + 1) * sizeof(WCHAR));
- sys_memcpy(result->data, LP_PREFIX, LP_PREFIX_SIZE);
+ sys_memcpy(result->data, LP_FILE_PREFIX, LP_PREFIX_SIZE);
actual_length += LP_PREFIX_LENGTH;
}
@@ -200,13 +226,19 @@ static int normalize_path_result(ErlNifBinary *path) {
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));
- }
+ if(IS_LONG_UNC_PATH(length, path_start)) {
+ /* The first two characters (\\) are the same for both long and short
+ * UNC paths. */
+ sys_memmove(&path_start[2], &path_start[LP_UNC_PREFIX_LENGTH],
+ (length - LP_UNC_PREFIX_LENGTH) * sizeof(WCHAR));
+
+ length -= LP_UNC_PREFIX_LENGTH - 2;
+ } else if(IS_LONG_PATH(length, path_start)) {
+ length -= LP_PREFIX_LENGTH;
+
+ sys_memmove(path_start, &path_start[LP_PREFIX_LENGTH],
+ length * sizeof(WCHAR));
}
path_end = &path_start[length];
@@ -318,49 +350,55 @@ static int has_same_mount_point(const efile_path_t *path_a, const efile_path_t *
/* 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;
+ const WCHAR *path_start, *path_end, *path_iterator;
int length;
ASSERT_PATH_FORMAT(path);
- path_start = (WCHAR*)path->data + LP_PREFIX_LENGTH;
- length = PATH_LENGTH(path) - LP_PREFIX_LENGTH;
+ if(!IS_LONG_UNC_PATH(PATH_LENGTH(path), path->data)) {
+ 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(length == 1) {
+ return IS_SLASH(path_start[0]);
+ }
- if(!IS_SLASH(path_start[0]) || !IS_SLASH(path_start[1])) {
- return 0;
+ /* Drive letter. */
+ if(length == 3 && iswalpha(path_start[0]) && path_start[1] == L':') {
+ return IS_SLASH(path_start[2]);
}
- path_iterator = path_start + 2;
+ return 0;
+ }
- /* Slide to the slash between the server and share names, if present. */
- while(path_iterator < path_end && !IS_SLASH(*path_iterator)) {
- path_iterator++;
- }
+ /* Check whether we're a UNC root, eg. \\server, \\server\share */
- /* 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));
+ path_start = (WCHAR*)path->data + LP_UNC_PREFIX_LENGTH;
+ length = PATH_LENGTH(path) - LP_UNC_PREFIX_LENGTH;
- /* 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]);
+ path_end = &path_start[length];
+ path_iterator = path_start;
+
+ /* Server name must be at least one character. */
+ if(length <= 1) {
+ return 0;
}
- return 0;
+ /* 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]);
}
posix_errno_t efile_open(const efile_path_t *path, enum efile_modes_t modes,
@@ -687,7 +725,7 @@ static int is_name_surrogate(const efile_path_t *path) {
if(handle != INVALID_HANDLE_VALUE) {
REPARSE_GUID_DATA_BUFFER reparse_buffer;
- LPDWORD unused_length;
+ DWORD unused_length;
BOOL success;
success = DeviceIoControl(handle,
@@ -1248,11 +1286,22 @@ posix_errno_t efile_set_cwd(const efile_path_t *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;
+ * starting with \\ are UNC paths, so we have to skip the long-path prefix.
+ *
+ * _wchdir doesn't handle long-prefixed UNC paths either so we hand those
+ * to SetCurrentDirectoryW instead. The per-drive working directory is
+ * irrelevant for such paths anyway. */
- if(_wchdir(path_start)) {
- return windows_to_posix_errno(GetLastError());
+ if(!IS_LONG_UNC_PATH(PATH_LENGTH(path), path->data)) {
+ path_start = (WCHAR*)path->data + LP_PREFIX_LENGTH;
+
+ if(_wchdir(path_start)) {
+ return windows_to_posix_errno(GetLastError());
+ }
+ } else {
+ if(!SetCurrentDirectoryW((WCHAR*)path->data)) {
+ return windows_to_posix_errno(GetLastError());
+ }
}
return 0;
@@ -1333,7 +1382,7 @@ posix_errno_t efile_altname(ErlNifEnv *env, const efile_path_t *path, ERL_NIF_TE
int name_length;
/* Reject path wildcards. */
- if(wcspbrk(&((const WCHAR*)path->data)[4], L"?*")) {
+ if(wcspbrk(&((const WCHAR*)path->data)[LP_PREFIX_LENGTH], L"?*")) {
return ENOENT;
}