2.2.1.1.3 Wildcards

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Some SMB requests allow wildcards to be used in a file name. Wildcards allow a client to operate on a number of files as a unit without having to separately enumerate the files and operate on them individually.<10>

Two wild card characters, the question mark and the asterisk, are used to match files whose names are selected by the wildcard string used as a selection criterion. The "?" (question mark) character matches a single character. If a file name selection criterion contains one or more "?" characters, then exactly that number of characters is matched by the wildcards. For example, the criterion "??x" matches "abx" but not "abcx" or "ax", because the two file names do not have enough characters preceding the literal. When a file name criterion has "?" characters trailing a literal, then the match is made with specified number of characters or less. For example, the criterion "x??" matches "xab", "xa", and "x", but not "xabc". If only "?" characters are present in the file name selection criterion, then the match is made as if the criterion contained "?" characters trailing a literal. The "*" (asterisk) character matches an entire file name. A null or empty specification criterion also selects all file names. For example, "*.abc" or ".abc" match any file with an extension of "abc". "*.*", "*", or empty string("") match all files in a directory.

If the negotiated dialect is NT LAN Manager or later, and the filename in the client request contains any of the following wildcards, the server SHOULD translate them as follows and the server MUST use the resulting string to attempt the file operation:

  • Translate the ? literal to >

  • Translate the . literal to " if it is immediately followed by a ? or a *

  • Translate the * literal to < if it is immediately followed by a .