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Acbosgd.179 net.general utzoo!decvax!ucbvax!ihnss!cbosg!cbosgd!mark Sat Dec 5 20:30:19 1981 Re: query about long unames There are a number of UNIX programs that have the magic numbers 6, 7, 8, 9, and 10 embedded in them. For example, they appear in ls, who, /etc/utmp, uucp, and sccs. In most cases, it is sufficient to find all of them and fix the numbers. They can be found in array decls, checks of the last character (like the 8th one in utmp, since then it isn't null terminated), and even in printf formats (there is a %-6.6s in the ls command in v7!)

Before 4BSD, I made extensive use of the grep command and went around changing things to use the sizeof function wherever possible. This introduced several remote formats. The intent was to upgrade to 14 character user names (sorry, but to me "uname" means the name of the system, not the login) at Berkeley. However, this never happened, and so the changes made were never tested for any case other than 8.

In almost all cases, changing the sizes and recompiling will solve the problem. The one exception is UUCP. The problem is that UUCP sends across the link, the name of the user who requested the action, for logging purposes and so that mail can be returned if it fails. This name is kept in a 10 byte buffer. So if sites A and B have a UUCP link, and A has long names, if one of these long named people sends mail to B, it can overflow the buffer on B (which does not check) and wedge the connection until the message is removed manually. Presumably a site that has long names should truncate the name to 7 letters before sending it across. Note that the higher level mail software does not care about how long your mailing address is, so there is no need to truncate mailing addresses at the user visible level.

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