lix/src/nix/upgrade-nix.cc
Eelco Dolstra ba87b08f85
getEnv(): Return std::optional
This allows distinguishing between an empty value and no value.
2019-11-22 16:18:13 +01:00

161 lines
4.9 KiB
C++

#include "command.hh"
#include "common-args.hh"
#include "store-api.hh"
#include "download.hh"
#include "eval.hh"
#include "attr-path.hh"
#include "names.hh"
#include "progress-bar.hh"
using namespace nix;
struct CmdUpgradeNix : MixDryRun, StoreCommand
{
Path profileDir;
std::string storePathsUrl = "https://github.com/NixOS/nixpkgs/raw/master/nixos/modules/installer/tools/nix-fallback-paths.nix";
CmdUpgradeNix()
{
mkFlag()
.longName("profile")
.shortName('p')
.labels({"profile-dir"})
.description("the Nix profile to upgrade")
.dest(&profileDir);
mkFlag()
.longName("nix-store-paths-url")
.labels({"url"})
.description("URL of the file that contains the store paths of the latest Nix release")
.dest(&storePathsUrl);
}
std::string name() override
{
return "upgrade-nix";
}
std::string description() override
{
return "upgrade Nix to the latest stable version";
}
Examples examples() override
{
return {
Example{
"To upgrade Nix to the latest stable version:",
"nix upgrade-nix"
},
Example{
"To upgrade Nix in a specific profile:",
"nix upgrade-nix -p /nix/var/nix/profiles/per-user/alice/profile"
},
};
}
void run(ref<Store> store) override
{
evalSettings.pureEval = true;
if (profileDir == "")
profileDir = getProfileDir(store);
printInfo("upgrading Nix in profile '%s'", profileDir);
Path storePath;
{
Activity act(*logger, lvlInfo, actUnknown, "querying latest Nix version");
storePath = getLatestNix(store);
}
auto version = DrvName(storePathToName(storePath)).version;
if (dryRun) {
stopProgressBar();
printError("would upgrade to version %s", version);
return;
}
{
Activity act(*logger, lvlInfo, actUnknown, fmt("downloading '%s'...", storePath));
store->ensurePath(storePath);
}
{
Activity act(*logger, lvlInfo, actUnknown, fmt("verifying that '%s' works...", storePath));
auto program = storePath + "/bin/nix-env";
auto s = runProgram(program, false, {"--version"});
if (s.find("Nix") == std::string::npos)
throw Error("could not verify that '%s' works", program);
}
stopProgressBar();
{
Activity act(*logger, lvlInfo, actUnknown, fmt("installing '%s' into profile '%s'...", storePath, profileDir));
runProgram(settings.nixBinDir + "/nix-env", false,
{"--profile", profileDir, "-i", storePath, "--no-sandbox"});
}
printError(ANSI_GREEN "upgrade to version %s done" ANSI_NORMAL, version);
}
/* Return the profile in which Nix is installed. */
Path getProfileDir(ref<Store> store)
{
Path where;
for (auto & dir : tokenizeString<Strings>(getEnv("PATH").value_or(""), ":"))
if (pathExists(dir + "/nix-env")) {
where = dir;
break;
}
if (where == "")
throw Error("couldn't figure out how Nix is installed, so I can't upgrade it");
printInfo("found Nix in '%s'", where);
if (hasPrefix(where, "/run/current-system"))
throw Error("Nix on NixOS must be upgraded via 'nixos-rebuild'");
Path profileDir = dirOf(where);
// Resolve profile to /nix/var/nix/profiles/<name> link.
while (canonPath(profileDir).find("/profiles/") == std::string::npos && isLink(profileDir))
profileDir = readLink(profileDir);
printInfo("found profile '%s'", profileDir);
Path userEnv = canonPath(profileDir, true);
if (baseNameOf(where) != "bin" ||
!hasSuffix(userEnv, "user-environment"))
throw Error("directory '%s' does not appear to be part of a Nix profile", where);
if (!store->isValidPath(userEnv))
throw Error("directory '%s' is not in the Nix store", userEnv);
return profileDir;
}
/* Return the store path of the latest stable Nix. */
Path getLatestNix(ref<Store> store)
{
// FIXME: use nixos.org?
auto req = DownloadRequest(storePathsUrl);
auto res = getDownloader()->download(req);
auto state = std::make_unique<EvalState>(Strings(), store);
auto v = state->allocValue();
state->eval(state->parseExprFromString(*res.data, "/no-such-path"), *v);
Bindings & bindings(*state->allocBindings(0));
auto v2 = findAlongAttrPath(*state, settings.thisSystem, bindings, *v);
return state->forceString(*v2);
}
};
static RegisterCommand r1(make_ref<CmdUpgradeNix>());