* Magic attribute `exportReferencesGraph' that allows the references

graph to be passed to a builder.  This attribute should be a list of
  pairs [name1 path1 name2 path2 ...].  The references graph of each
  `pathN' will be stored in a text file `nameN' in the temporary build
  directory.  The text files have the format used by `nix-store
  --register-validity'.  However, the deriver fields are left empty.

  `exportReferencesGraph' is useful for builders that want to do
  something with the closure of a store path.  Examples: the builders
  that make initrds and ISO images for NixOS.

  `exportReferencesGraph' is entirely pure.  It's necessary because
  otherwise the only way for a builder to get this information would
  be to call `nix-store' directly, which is not allowed (though
  unfortunately possible).
This commit is contained in:
Eelco Dolstra 2006-11-13 18:18:13 +00:00
parent e40d4a5604
commit e2a70b7ec0
3 changed files with 65 additions and 21 deletions

View file

@ -30,10 +30,14 @@
<listitem><para>TODO: now using Berkeley DB 4.5.</para></listitem>
<listitem><para>Option <option>--reregister</option> in
<listitem><para>TODO: option <option>--reregister</option> in
<command>nix-store --register-validity</command>.</para></listitem>
<listitem><para>TODO: magic <varname>exportReferencesGraph</varname>
attribute.</para></listitem>
</itemizedlist>
</section>

View file

@ -901,6 +901,34 @@ string showPaths(const PathSet & paths)
}
/* Return a string accepted by `nix-store --register-validity' that
registers the specified paths as valid. Note: it's the
responsibility of the caller to provide a closure. */
static string makeValidityRegistration(const PathSet & paths,
bool showDerivers)
{
string s = "";
for (PathSet::iterator i = paths.begin(); i != paths.end(); ++i) {
s += *i + "\n";
Path deriver = showDerivers ? queryDeriver(noTxn, *i) : "";
s += deriver + "\n";
PathSet references;
queryReferences(noTxn, *i, references);
s += (format("%1%\n") % references.size()).str();
for (PathSet::iterator j = references.begin();
j != references.end(); ++j)
s += *j + "\n";
}
return s;
}
DerivationGoal::HookReply DerivationGoal::tryBuildHook()
{
Path buildHook = getEnv("NIX_BUILD_HOOK");
@ -1024,26 +1052,8 @@ DerivationGoal::HookReply DerivationGoal::tryBuildHook()
/* The `references' file has exactly the format accepted by
`nix-store --register-validity'. */
s = "";
for (PathSet::iterator i = allInputs.begin();
i != allInputs.end(); ++i)
{
s += *i + "\n";
Path deriver = queryDeriver(noTxn, *i);
s += deriver + "\n";
PathSet references;
queryReferences(noTxn, *i, references);
s += (format("%1%\n") % references.size()).str();
for (PathSet::iterator j = references.begin();
j != references.end(); ++j)
s += *j + "\n";
}
writeStringToFile(referencesFN, s);
writeStringToFile(referencesFN,
makeValidityRegistration(allInputs, true));
/* Tell the hook to proceed. */
writeLine(toHook.writeSide, "okay");
@ -1235,6 +1245,32 @@ void DerivationGoal::startBuilder()
env[*i] = getEnv(*i);
}
/* The `exportReferencesGraph' feature allows the references graph
to be passed to a builder. This attribute should be a list of
pairs [name1 path1 name2 path2 ...]. The references graph of
each `pathN' will be stored in a text file `nameN' in the
temporary build directory. The text files have the format used
by `nix-store --register-validity'. However, the deriver
fields are left empty. */
string s = drv.env["exportReferencesGraph"];
Strings ss = tokenizeString(s);
if (ss.size() % 2 != 0)
throw Error(format("odd number of tokens in `exportReferencesGraph': `%1%'") % s);
for (Strings::iterator i = ss.begin(); i != ss.end(); ) {
string fileName = *i++;
Path storePath = *i++;
if (!isValidPath(storePath))
throw Error(format("`exportReferencesGraph' refers to an invalid path `%1%'")
% storePath);
checkStoreName(fileName); /* !!! abuse of this function */
PathSet refs;
computeFSClosure(storePath, refs);
/* !!! in secure Nix, the writing should be done on the
build uid for security (maybe). */
writeStringToFile(tmpDir + "/" + fileName,
makeValidityRegistration(refs, false));
}
/* If we are running as root, and the `build-allow-root' setting
is `false', then we have to build as one of the users listed in

View file

@ -259,6 +259,10 @@ Path toStorePath(const Path & path)
void checkStoreName(const string & name)
{
string validChars = "+-._?=";
/* Disallow names starting with a dot for possible security
reasons (e.g., "." and ".."). */
if (string(name, 0, 1) == ".")
throw Error(format("illegal name: `%1%'") % name);
for (string::const_iterator i = name.begin(); i != name.end(); ++i)
if (!((*i >= 'A' && *i <= 'Z') ||
(*i >= 'a' && *i <= 'z') ||