On Sun, Feb 20, 2000 at 01:57:53PM -0500, Daniel Barclay wrote: > > Where can I get a clear and consistent specification of how apt-get > interprets a sources.list file? Read the source? ... Actually, i don't think it's explicitly stated anywhere else. > What is unclear is exactly how apt-get maps to full directory names or URIs > from the various pieces (initial URI or directory, distribution name, and > component names given in sources.list, and "Filename:" entries in Packages > files). I'll try to explain. Hopefully i have everything right ;) > Specifically: > - Does apt-get assume or require directory "dists" somewhere in the > directory hierarchy? > > I can't tell whether apt-get is hard-coded to add "dists" at some level, > apt-get defaults to that but can be overridden, or "dists" comes from the > "Filename:" entries in some Packages.gz files. See below. I'll be using variables to make discussion easier. As you know, there's two line formats: deb $base $distribution $component $component ... deb $base $distribution/ In the Packages file, there's a field formatted like this: Filename: $field_Filename $arch is your archetecture, e.g. i386. "dpkg --print-architecture" will tell you. > - How _exactly_ does apt-get assemble the URI, the distribution name, and > any component names to find Packages.gz files? There's two formats for a sources.list entry. With components, it plugs it into a format something like this for finding the Package file $(base)/dists/$(distribution)/$(component)/binary-$(arch)/Packages[.gz] Without components, it just puts things together like this, no 'dists': $(base)/$(distribution)/Packages[.gz] > - How _exactly_ does apt-get combine the URI, distribution, and component > names with the pathnames in "Filename:" entries in Packages files to find > *.deb files? For finding files to download, it adds the Filename entry to $(base): $(base)/$(field_Filename) > That is, how can I figure out exactly how I must name and organize local > directories for local mirrors of Debian, KDE, or GNOME releases, and how > can I figure out exactly how to construct source.list entries to point to > those local mirrors? Put together, $base and $field_Filename should completely specify the URI to the file. Put together by the rules above, $base, $distribution, and components should lead to the Packages[.gz] file. You can use dpkg-scanpackages, from the dpkg-dev package, to rebuild the Packages file if necessary. > The manual page for sources.list (at least version 0.3.10slink11) is > quite ambiguous and also contradicts itself, leaving several things > unclear: > > * The sources.list manual page says that the URI field "must specify the > base of the Debian distribution." > > Which directory is the "base"? > > For "ftp://ftp.debian.org/pub/debian/dists/slink/main/...";, which level is > the base of the distribution? Is it: > - "ftp://ftp.debian.org/pub/debian/dists/slink";, > - "ftp://ftp.debian.org/pub/debian/dists";, or > - "ftp://ftp.debian.org/pub/debian"; ? > That is, is the base URI the directory that contains "dists"? the one > that contains the directory named by the "distribution" field in the > source.list line? $base is "ftp://ftp.debian.org/pub/debian"; $distribution is "slink" $component is "main" Packages.gz is in ftp://ftp.debian.org/pub/debian/dists/slink/main/binary-$(arch)/ In Packages.gz, $field_Filename is such that the deb is at ftp://ftp.debian.org/pub/debian/$field_Filename > (Also, does it matter whether the base URI ends with a slash?) i believe $base shouldn't end with a slash. i don't know if it matters, i've never tested it. > * Soon after, the manual page says: > distribution can specify an exact path, in which case the components > must be omitted and distribution must end with a slash (/). ... If > distribution does not specify an exact path, at least one component > must be present. > > However, about four paragraphs down, it says: > > Some examples: > > deb http://http.us.debian.org/debian stable main contrib non-free > > deb http://http.us.debian.org/debian dists/stable-updates > > In the second example, the distribution field does not end with a slash, > but the components are omitted. That directly contradicts what was > specified above. Looks like a bug in the manpage to me... Still present in the latest unstable apt, too. Putting that line into my sources.list makes apt give an error. > So, is there any complete (and correct) description of how apt-get > manipulates all these pieces of file pathnames? I hope this came close ;) -- finger for GPG public key.
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