lix/src/libstore/derivations.cc
John Ericson 3804e3df9b Don't anticipate hash algo without hash in derivation for now
When we merge with master, the new lack of string types make this case
impossible (after parsing). Later, when we actually implemenent
CA-derivations, we'll change the types to allow that.
2020-06-21 21:05:37 +00:00

506 lines
14 KiB
C++

#include "derivations.hh"
#include "store-api.hh"
#include "globals.hh"
#include "util.hh"
#include "worker-protocol.hh"
#include "fs-accessor.hh"
#include "istringstream_nocopy.hh"
namespace nix {
// Avoid shadow
HashType parseHashAlgo(const string & s) {
return parseHashType(s);
}
void DerivationOutput::parseHashType(FileIngestionMethod & recursive, HashType & hashType) const
{
recursive = FileIngestionMethod::Flat;
string algo = hashAlgo;
if (string(algo, 0, 2) == "r:") {
recursive = FileIngestionMethod::Recursive;
algo = string(algo, 2);
}
HashType hashType_loc = parseHashAlgo(algo);
if (hashType_loc == htUnknown)
throw Error("unknown hash algorithm '%s'", algo);
hashType = hashType_loc;
}
void DerivationOutput::parseHashInfo(FileIngestionMethod & recursive, Hash & hash) const
{
HashType hashType;
parseHashType(recursive, hashType);
hash = Hash(this->hash, hashType);
}
bool derivationIsCA(DerivationType dt) {
switch (dt) {
case DerivationType::Regular: return false;
case DerivationType::CAFixed: return true;
};
// Since enums can have non-variant values, but making a `default:` would
// disable exhaustiveness warnings.
abort();
}
bool derivationIsFixed(DerivationType dt) {
switch (dt) {
case DerivationType::Regular: return false;
case DerivationType::CAFixed: return true;
};
abort();
}
bool derivationIsImpure(DerivationType dt) {
switch (dt) {
case DerivationType::Regular: return false;
case DerivationType::CAFixed: return true;
};
abort();
}
const StorePath & BasicDerivation::findOutput(const string & id) const
{
auto i = outputs.find(id);
if (i == outputs.end())
throw Error("derivation has no output '%s'", id);
return i->second.path;
}
bool BasicDerivation::isBuiltin() const
{
return string(builder, 0, 8) == "builtin:";
}
StorePath writeDerivation(ref<Store> store,
const Derivation & drv, std::string_view name, RepairFlag repair)
{
auto references = drv.inputSrcs;
for (auto & i : drv.inputDrvs)
references.insert(i.first);
/* Note that the outputs of a derivation are *not* references
(that can be missing (of course) and should not necessarily be
held during a garbage collection). */
auto suffix = std::string(name) + drvExtension;
auto contents = drv.unparse(*store, false);
return settings.readOnlyMode
? store->computeStorePathForText(suffix, contents, references)
: store->addTextToStore(suffix, contents, references, repair);
}
/* Read string `s' from stream `str'. */
static void expect(std::istream & str, const string & s)
{
char s2[s.size()];
str.read(s2, s.size());
if (string(s2, s.size()) != s)
throw FormatError("expected string '%1%'", s);
}
/* Read a C-style string from stream `str'. */
static string parseString(std::istream & str)
{
string res;
expect(str, "\"");
int c;
while ((c = str.get()) != '"')
if (c == '\\') {
c = str.get();
if (c == 'n') res += '\n';
else if (c == 'r') res += '\r';
else if (c == 't') res += '\t';
else res += c;
}
else res += c;
return res;
}
static Path parsePath(std::istream & str)
{
string s = parseString(str);
if (s.size() == 0 || s[0] != '/')
throw FormatError("bad path '%1%' in derivation", s);
return s;
}
static bool endOfList(std::istream & str)
{
if (str.peek() == ',') {
str.get();
return false;
}
if (str.peek() == ']') {
str.get();
return true;
}
return false;
}
static StringSet parseStrings(std::istream & str, bool arePaths)
{
StringSet res;
while (!endOfList(str))
res.insert(arePaths ? parsePath(str) : parseString(str));
return res;
}
static Derivation parseDerivation(const Store & store, const string & s)
{
Derivation drv;
istringstream_nocopy str(s);
expect(str, "Derive([");
/* Parse the list of outputs. */
while (!endOfList(str)) {
expect(str, "("); std::string id = parseString(str);
expect(str, ","); auto path = store.parseStorePath(parsePath(str));
expect(str, ","); auto hashAlgo = parseString(str);
expect(str, ","); auto hash = parseString(str);
expect(str, ")");
drv.outputs.emplace(id, DerivationOutput {
.path = std::move(path),
.hashAlgo = std::move(hashAlgo),
.hash = std::move(hash)
});
}
/* Parse the list of input derivations. */
expect(str, ",[");
while (!endOfList(str)) {
expect(str, "(");
Path drvPath = parsePath(str);
expect(str, ",[");
drv.inputDrvs.insert_or_assign(store.parseStorePath(drvPath), parseStrings(str, false));
expect(str, ")");
}
expect(str, ",["); drv.inputSrcs = store.parseStorePathSet(parseStrings(str, true));
expect(str, ","); drv.platform = parseString(str);
expect(str, ","); drv.builder = parseString(str);
/* Parse the builder arguments. */
expect(str, ",[");
while (!endOfList(str))
drv.args.push_back(parseString(str));
/* Parse the environment variables. */
expect(str, ",[");
while (!endOfList(str)) {
expect(str, "("); string name = parseString(str);
expect(str, ","); string value = parseString(str);
expect(str, ")");
drv.env[name] = value;
}
expect(str, ")");
return drv;
}
Derivation readDerivation(const Store & store, const Path & drvPath)
{
try {
return parseDerivation(store, readFile(drvPath));
} catch (FormatError & e) {
throw Error("error parsing derivation '%1%': %2%", drvPath, e.msg());
}
}
Derivation Store::derivationFromPath(const StorePath & drvPath)
{
ensurePath(drvPath);
return readDerivation(drvPath);
}
Derivation Store::readDerivation(const StorePath & drvPath)
{
auto accessor = getFSAccessor();
try {
return parseDerivation(*this, accessor->readFile(printStorePath(drvPath)));
} catch (FormatError & e) {
throw Error("error parsing derivation '%s': %s", printStorePath(drvPath), e.msg());
}
}
static void printString(string & res, std::string_view s)
{
char buf[s.size() * 2 + 2];
char * p = buf;
*p++ = '"';
for (auto c : s)
if (c == '\"' || c == '\\') { *p++ = '\\'; *p++ = c; }
else if (c == '\n') { *p++ = '\\'; *p++ = 'n'; }
else if (c == '\r') { *p++ = '\\'; *p++ = 'r'; }
else if (c == '\t') { *p++ = '\\'; *p++ = 't'; }
else *p++ = c;
*p++ = '"';
res.append(buf, p - buf);
}
static void printUnquotedString(string & res, std::string_view s)
{
res += '"';
res.append(s);
res += '"';
}
template<class ForwardIterator>
static void printStrings(string & res, ForwardIterator i, ForwardIterator j)
{
res += '[';
bool first = true;
for ( ; i != j; ++i) {
if (first) first = false; else res += ',';
printString(res, *i);
}
res += ']';
}
template<class ForwardIterator>
static void printUnquotedStrings(string & res, ForwardIterator i, ForwardIterator j)
{
res += '[';
bool first = true;
for ( ; i != j; ++i) {
if (first) first = false; else res += ',';
printUnquotedString(res, *i);
}
res += ']';
}
string Derivation::unparse(const Store & store, bool maskOutputs,
std::map<std::string, StringSet> * actualInputs) const
{
string s;
s.reserve(65536);
s += "Derive([";
bool first = true;
for (auto & i : outputs) {
if (first) first = false; else s += ',';
s += '('; printUnquotedString(s, i.first);
s += ','; printUnquotedString(s, maskOutputs ? "" : store.printStorePath(i.second.path));
s += ','; printUnquotedString(s, i.second.hashAlgo);
s += ','; printUnquotedString(s, i.second.hash);
s += ')';
}
s += "],[";
first = true;
if (actualInputs) {
for (auto & i : *actualInputs) {
if (first) first = false; else s += ',';
s += '('; printUnquotedString(s, i.first);
s += ','; printUnquotedStrings(s, i.second.begin(), i.second.end());
s += ')';
}
} else {
for (auto & i : inputDrvs) {
if (first) first = false; else s += ',';
s += '('; printUnquotedString(s, store.printStorePath(i.first));
s += ','; printUnquotedStrings(s, i.second.begin(), i.second.end());
s += ')';
}
}
s += "],";
auto paths = store.printStorePathSet(inputSrcs); // FIXME: slow
printUnquotedStrings(s, paths.begin(), paths.end());
s += ','; printUnquotedString(s, platform);
s += ','; printString(s, builder);
s += ','; printStrings(s, args.begin(), args.end());
s += ",[";
first = true;
for (auto & i : env) {
if (first) first = false; else s += ',';
s += '('; printString(s, i.first);
s += ','; printString(s, maskOutputs && outputs.count(i.first) ? "" : i.second);
s += ')';
}
s += "])";
return s;
}
// FIXME: remove
bool isDerivation(const string & fileName)
{
return hasSuffix(fileName, drvExtension);
}
DerivationType BasicDerivation::type() const
{
if (outputs.size() == 1 &&
outputs.begin()->first == "out" &&
outputs.begin()->second.hash != "")
{
return DerivationType::CAFixed;
} else {
return DerivationType::Regular;
}
}
DrvHashes drvHashes;
/* Returns the hash of a derivation modulo fixed-output
subderivations. A fixed-output derivation is a derivation with one
output (`out') for which an expected hash and hash algorithm are
specified (using the `outputHash' and `outputHashAlgo'
attributes). We don't want changes to such derivations to
propagate upwards through the dependency graph, changing output
paths everywhere.
For instance, if we change the url in a call to the `fetchurl'
function, we do not want to rebuild everything depending on it
(after all, (the hash of) the file being downloaded is unchanged).
So the *output paths* should not change. On the other hand, the
*derivation paths* should change to reflect the new dependency
graph.
That's what this function does: it returns a hash which is just the
hash of the derivation ATerm, except that any input derivation
paths have been replaced by the result of a recursive call to this
function, and that for fixed-output derivations we return a hash of
its output path. */
Hash hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutputs)
{
/* Return a fixed hash for fixed-output derivations. */
switch (drv.type()) {
case DerivationType::CAFixed: {
DerivationOutputs::const_iterator i = drv.outputs.begin();
return hashString(htSHA256, "fixed:out:"
+ i->second.hashAlgo + ":"
+ i->second.hash + ":"
+ store.printStorePath(i->second.path));
}
default:
break;
}
/* For other derivations, replace the inputs paths with recursive
calls to this function.*/
std::map<std::string, StringSet> inputs2;
for (auto & i : drv.inputDrvs) {
auto h = drvHashes.find(i.first);
if (h == drvHashes.end()) {
assert(store.isValidPath(i.first));
h = drvHashes.insert_or_assign(i.first, hashDerivationModulo(store,
store.readDerivation(i.first), false)).first;
}
inputs2.insert_or_assign(h->second.to_string(Base16, false), i.second);
}
return hashString(htSHA256, drv.unparse(store, maskOutputs, &inputs2));
}
std::string StorePathWithOutputs::to_string(const Store & store) const
{
return outputs.empty()
? store.printStorePath(path)
: store.printStorePath(path) + "!" + concatStringsSep(",", outputs);
}
bool wantOutput(const string & output, const std::set<string> & wanted)
{
return wanted.empty() || wanted.find(output) != wanted.end();
}
StorePathSet BasicDerivation::outputPaths() const
{
StorePathSet paths;
for (auto & i : outputs)
paths.insert(i.second.path);
return paths;
}
StringSet BasicDerivation::outputNames() const
{
StringSet names;
for (auto & i : outputs)
names.insert(i.first);
return names;
}
Source & readDerivation(Source & in, const Store & store, BasicDerivation & drv)
{
drv.outputs.clear();
auto nr = readNum<size_t>(in);
for (size_t n = 0; n < nr; n++) {
auto name = readString(in);
auto path = store.parseStorePath(readString(in));
auto hashAlgo = readString(in);
auto hash = readString(in);
drv.outputs.emplace(name, DerivationOutput {
.path = std::move(path),
.hashAlgo = std::move(hashAlgo),
.hash = std::move(hash)
});
}
drv.inputSrcs = readStorePaths<StorePathSet>(store, in);
in >> drv.platform >> drv.builder;
drv.args = readStrings<Strings>(in);
nr = readNum<size_t>(in);
for (size_t n = 0; n < nr; n++) {
auto key = readString(in);
auto value = readString(in);
drv.env[key] = value;
}
return in;
}
void writeDerivation(Sink & out, const Store & store, const BasicDerivation & drv)
{
out << drv.outputs.size();
for (auto & i : drv.outputs)
out << i.first << store.printStorePath(i.second.path) << i.second.hashAlgo << i.second.hash;
writeStorePaths(store, out, drv.inputSrcs);
out << drv.platform << drv.builder << drv.args;
out << drv.env.size();
for (auto & i : drv.env)
out << i.first << i.second;
}
std::string hashPlaceholder(const std::string & outputName)
{
// FIXME: memoize?
return "/" + hashString(htSHA256, "nix-output:" + outputName).to_string(Base32, false);
}
}