win32: Fix enumerate root dir content on SFTP-server (#148)

https://github.com/PowerShell/Win32-OpenSSH/issues/539

contrib/win32/win32compat/fileio.c

@@ -745,12 +745,21 @@ fileio_stat(const char *path, struct _stat64 *buf)
 	wchar_t* wpath = NULL;
 	WIN32_FILE_ATTRIBUTE_DATA attributes = { 0 };
 	int ret = -1, len = 0;	
+
+	memset(buf, 0, sizeof(struct _stat64));
+
+	/* Detect root dir */
+	if (path && strcmp(path, "/") == 0) {
+		buf->st_mode = _S_IFDIR | _S_IREAD | 0xFF;
+		buf->st_dev = USHRT_MAX;   // rootdir flag
+		return 0;
+	}
+
 	if ((wpath = utf8_to_utf16(path)) == NULL) {
 		errno = errno_from_Win32LastError();
 		debug3("utf8_to_utf16 failed for file:%s error:%d", path, GetLastError());
 		return -1;
 	}
-	memset(buf, 0, sizeof(struct _stat64));
 
 	if (GetFileAttributesExW(wpath, GetFileExInfoStandard, &attributes) == FALSE) {
 		errno = errno_from_Win32LastError();

contrib/win32/win32compat/misc.c

@@ -851,6 +851,16 @@ convertToBackslash(char *str)
 	}
 }
 
+void
+convertToBackslashW(wchar_t *str)
+{
+	while (*str) {
+		if (*str == L'/')
+			*str = L'\\';
+		str++;
+	}
+}
+
 /* convert back slash to forward slash */
 void
 convertToForwardslash(char *str)
@@ -874,9 +884,9 @@ realpath(const char *path, char resolved[PATH_MAX])
 	char tempPath[PATH_MAX];
 
 	if ((path[0] == '/') && path[1] && (path[2] == ':'))
-		strncpy(resolved, path + 1, strlen(path)); /* skip the first '/' */
+		strncpy(resolved, path + 1, PATH_MAX); /* skip the first '/' */
 	else
-		strncpy(resolved, path, strlen(path) + 1);
+		strncpy(resolved, path, PATH_MAX);
 
 	if ((resolved[0]) && (resolved[1] == ':') && (resolved[2] == '\0')) { /* make "x:" as "x:\\" */
 		resolved[2] = '\\';
@@ -889,7 +899,7 @@ realpath(const char *path, char resolved[PATH_MAX])
 	convertToForwardslash(tempPath);
 
 	resolved[0] = '/'; /* will be our first slash in /x:/users/test1 format */
-	strncpy(resolved + 1, tempPath, sizeof(tempPath) - 1);
+	strncpy(resolved + 1, tempPath, PATH_MAX - 1);
 	return resolved;
 }
 

contrib/win32/win32compat/misc_internal.h

@@ -4,6 +4,12 @@
 #define SSH_ASYNC_STDOUT "SSH_ASYNC_STDOUT"
 #define SSH_ASYNC_STDERR "SSH_ASYNC_STDERR"
 
+#define GOTO_CLEANUP_IF(_cond_,_err_) do {  \
+    if ((_cond_)) {                         \
+        hr = _err_;                         \
+        goto cleanup;                       \
+    }                                       \
+} while(0)
 #define NULL_DEVICE "/dev/null"
 
 #define IS_INVALID_HANDLE(h) ( ((NULL == h) || (INVALID_HANDLE_VALUE == h)) ? 1 : 0 )
@@ -17,6 +23,7 @@ void w32posix_done();
 char* w32_programdir();
 
 void convertToBackslash(char *str);
+void convertToBackslashW(wchar_t *str);
 void convertToForwardslash(char *str);
 
 void unix_time_to_file_time(ULONG, LPFILETIME);

contrib/win32/win32compat/win32_dirent.c

@@ -42,8 +42,54 @@ struct DIR_ {
 	intptr_t hFile;
 	struct _wfinddata_t c_file;
 	int first;
+	wchar_t * nextdisk;
 };
 
+#define ATTR_ROOTDIR  UINT_MAX
+
+/* Enumerate all devices which have drive name.
+   Return a DIR stream on the root directory, or NULL if it could not be enumerated. */
+DIR *
+openrootdir(const char *name)
+{
+	int hr = 0;
+	DWORD dw;
+	DIR * pdir;
+	struct _wfinddata_t c_file = {0};
+	wchar_t * p;
+
+	dw = GetLogicalDriveStringsW(_countof(c_file.name) - 2, c_file.name);
+	if (!dw) {
+		errno = ENODEV;
+		return NULL;
+	}
+	c_file.attrib = ATTR_ROOTDIR;
+	c_file.size = 0;
+	p = c_file.name;
+	while (*p) {
+		size_t len = wcslen(p);
+		if (len == 0)
+			break;
+		p += len + 1;
+		c_file.size++;
+	}
+	if (c_file.size == 0) {
+		errno = ENODEV;
+		return NULL;
+	}
+	pdir = malloc(sizeof(DIR));
+	if (!pdir) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	memset(pdir, 0, sizeof(DIR));
+	pdir->hFile = 0;
+	memcpy(&pdir->c_file, &c_file, sizeof(c_file));
+	pdir->first = 1;
+
+	return pdir;
+}
+
 /* Open a directory stream on NAME.
    Return a DIR stream on the directory, or NULL if it could not be opened.  */
 DIR *
@@ -55,14 +101,31 @@ opendir(const char *name)
 	wchar_t searchstr[PATH_MAX];
 	wchar_t* wname = NULL;
 	int needed;
+	size_t len;
+
+	/* Detect root dir */
+	if (name && strcmp(name, "/") == 0)
+		return openrootdir(name);
 
 	if ((wname = utf8_to_utf16(sanitized_path(name))) == NULL) {
 		errno = ENOMEM;
 		return NULL;
 	}
 
+	convertToBackslashW(wname);
+	len = wcslen(wname);
+	if (len && wname[len-1] == L'\\') {
+		len--;
+		wname[len] = 0;
+	}
+	if (len >= PATH_MAX) {
+		free(wname);
+		errno = ENAMETOOLONG;
+		return NULL;
+	}
+
 	/* add *.* for Windows _findfirst() search pattern */
-	swprintf_s(searchstr, PATH_MAX, L"%s\\*.*", wname);
+	swprintf_s(searchstr, _countof(searchstr) - 1, L"%s\\*.*", wname);
 	free(wname);
 
 	if ((hFile = _wfindfirst(searchstr, &c_file)) == -1L)
@@ -92,13 +155,69 @@ closedir(DIR *dirp)
 
 	if (dirp && (dirp->hFile)) {
 		_findclose(dirp->hFile);
-		dirp->hFile = 0;
-		free(dirp);
 	}
+	free(dirp);
 
 	return 0;
 }
 
+/* Read a root directory entry from DIRP.
+   Return a pointer to a `struct dirent' describing the entry,
+   or NULL for EOF or error.  The storage returned may be overwritten
+   by a later readdir call on the same DIR stream.  */
+struct dirent *
+readrootdir(DIR * dirp)
+{
+	wchar_t * p;
+	size_t len = 0;
+	struct dirent *pdirentry;
+	UINT dt;
+	ULARGE_INTEGER totalNumberOfBytes;
+	BOOL x;
+
+	if (dirp->c_file.size <= 0) {
+		errno = ENODATA;
+		return NULL;
+	}
+	if (dirp->first) {
+		dirp->first = 0;
+		dirp->nextdisk = dirp->c_file.name;
+	}
+
+	p = dirp->nextdisk;
+
+	for ( ; ; p += len + 1) {
+		len = wcslen(p);
+		if (len == 0) {
+			dirp->nextdisk = p;
+			errno = ENODATA;
+			return NULL;     /* end of multi-string */
+		}
+
+		dt = GetDriveTypeW(p);
+		if (dt == DRIVE_UNKNOWN || dt == DRIVE_NO_ROOT_DIR || dt == DRIVE_RAMDISK)
+			continue;
+
+		x = GetDiskFreeSpaceExW(p, NULL, &totalNumberOfBytes, NULL);
+		if (!x || totalNumberOfBytes.QuadPart == 0)
+			continue;
+
+		break;   // process filtered disk
+	}
+	dirp->nextdisk = p + len + 1;
+
+	if ((pdirentry = malloc(sizeof(struct dirent))) == NULL) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	pdirentry->d_name[0] = (char)p[0];
+	pdirentry->d_name[1] = ':';
+	pdirentry->d_name[2] = 0;
+
+	pdirentry->d_ino = 1; // a fictious one like UNIX to say it is nonzero
+	return pdirentry;
+}
+
 /* Read a directory entry from DIRP.
    Return a pointer to a `struct dirent' describing the entry,
    or NULL for EOF or error.  The storage returned may be overwritten
@@ -113,6 +232,9 @@ readdir(void *avp)
 	DIR *dirp = (DIR *)avp;
 	char *tmp = NULL;
 
+	if (dirp->hFile == 0 && dirp->c_file.attrib == ATTR_ROOTDIR)
+		return readrootdir(dirp);
+
 	for (;;) {
 		if (dirp->first) {
 			memcpy(&c_file, &dirp->c_file, sizeof(c_file));
@@ -128,7 +250,7 @@ readdir(void *avp)
 			return NULL;
 		}
 
-		strncpy(pdirentry.d_name, tmp, strlen(tmp) + 1);
+		strncpy(pdirentry.d_name, tmp, sizeof(pdirentry.d_name));
 		free(tmp);
 
 		pdirentry.d_ino = 1; /* a fictious one like UNIX to say it is nonzero */