5c20ffbb2f
The GNU tar format defines the following type flags: TypeGNULongName = 'L' // Next file has a long name TypeGNULongLink = 'K' // Next file symlinks to a file w/ a long name Anytime a string exceeds the field dedicated to store it, the GNU format permits a fake "file" to be prepended where that file entry has a Typeflag of 'L' or 'K' and the contents of the file is a NUL-terminated string. Contrary to previous TODO comments, the GNU format supports arbitrary strings (without NUL) rather UTF-8 strings. The manual says the following: <<< The name, linkname, magic, uname, and gname are null-terminated character strings >>> <<< All characters in header blocks are represented by using 8-bit characters in the local variant of ASCII. >>> From this description, we gather the following: * We must forbid NULs in any GNU strings * Any 8-bit value (other than NUL) is permitted Since the modern world has moved to UTF-8, it is really difficult to determine what a "local variant of ASCII" means. For this reason, we treat strings as just an arbitrary binary string (without NUL) and leave it to the user to determine the encoding of this string. (Practically, it seems that UTF-8 is the typical encoding used in GNU archives seen in the wild). The implementation of GNU tar seems to confirm this interpretation of the manual where it permits any arbitrary binary string to exist within these fields so long as they do not contain the NUL character. $ touch `echo -e "not\x80\x81\x82\x83utf8"` $ gnutar -H gnu --tar -cvf gnu-not-utf8.tar $(echo -e "not\x80\x81\x82\x83utf8") The fact that we permit arbitrary binary in GNU strings goes hand-in-hand with the fact that GNU also permits a "base-256" encoding of numeric fields, which is effectively two-complement binary. Change-Id: Ic037ec6bed306d07d1312f0058594bd9b64d9880 Reviewed-on: https://go-review.googlesource.com/55573 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> |
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README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
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Download and Install
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After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.
Install From Source
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.
Contributing
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that the Go project does not use GitHub pull requests, and that we use the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.