lix/src/libfetchers/path.cc

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#include "fetchers.hh"
#include "store-api.hh"
namespace nix::fetchers {
struct PathInputScheme : InputScheme
{
std::optional<Input> inputFromURL(const ParsedURL & url) override
{
if (url.scheme != "path") return {};
if (url.authority && *url.authority != "")
throw Error("path URL '%s' should not have an authority ('%s')", url.url, *url.authority);
Input input;
input.attrs.insert_or_assign("type", "path");
input.attrs.insert_or_assign("path", url.path);
for (auto & [name, value] : url.query)
if (name == "rev" || name == "narHash")
input.attrs.insert_or_assign(name, value);
else if (name == "revCount" || name == "lastModified") {
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if (auto n = string2Int<uint64_t>(value))
input.attrs.insert_or_assign(name, *n);
else
throw Error("path URL '%s' has invalid parameter '%s'", url.to_string(), name);
}
else
throw Error("path URL '%s' has unsupported parameter '%s'", url.to_string(), name);
return input;
}
std::optional<Input> inputFromAttrs(const Attrs & attrs) override
{
if (maybeGetStrAttr(attrs, "type") != "path") return {};
getStrAttr(attrs, "path");
for (auto & [name, value] : attrs)
/* Allow the user to pass in "fake" tree info
attributes. This is useful for making a pinned tree
work the same as the repository from which is exported
(e.g. path:/nix/store/...-source?lastModified=1585388205&rev=b0c285...). */
if (name == "type" || name == "rev" || name == "revCount" || name == "lastModified" || name == "narHash" || name == "path")
// checked in Input::fromAttrs
;
else
throw Error("unsupported path input attribute '%s'", name);
Input input;
input.attrs = attrs;
return input;
}
ParsedURL toURL(const Input & input) override
{
auto query = attrsToQuery(input.attrs);
query.erase("path");
query.erase("type");
return ParsedURL {
.scheme = "path",
.path = getStrAttr(input.attrs, "path"),
.query = query,
};
}
bool hasAllInfo(const Input & input) override
{
return true;
}
std::optional<Path> getSourcePath(const Input & input) override
{
return getStrAttr(input.attrs, "path");
}
void markChangedFile(const Input & input, std::string_view file, std::optional<std::string> commitMsg) override
{
// nothing to do
}
std::pair<Tree, Input> fetch(ref<Store> store, const Input & input) override
{
std::string absPath;
auto path = getStrAttr(input.attrs, "path");
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if (path[0] != '/' && input.parent) {
auto parent = canonPath(*input.parent);
// the path isn't relative, prefix it
absPath = canonPath(parent + "/" + path);
// for security, ensure that if the parent is a store path, it's inside it
if (!parent.rfind(store->storeDir, 0) && absPath.rfind(store->storeDir, 0))
throw BadStorePath("relative path '%s' points outside of its parent's store path %s, this is a security violation", path, parent);
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} else
absPath = path;
// FIXME: check whether access to 'path' is allowed.
auto storePath = store->maybeParseStorePath(absPath);
if (storePath)
store->addTempRoot(*storePath);
if (!storePath || storePath->name() != "source" || !store->isValidPath(*storePath))
// FIXME: try to substitute storePath.
storePath = store->addToStore("source", absPath);
return {
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Tree(store->toRealPath(*storePath), std::move(*storePath)),
input
};
}
};
static auto rPathInputScheme = OnStartup([] { registerInputScheme(std::make_unique<PathInputScheme>()); });
}