Merge changes I8d87c0e9,I25937702 into main

* changes:
  nix3-upgrade-nix: always use the /new/ nix-env to perform the installation
  libutil: implement a realPath() utility
This commit is contained in:
Qyriad 2024-07-15 23:18:03 +00:00 committed by Gerrit Code Review
commit c052716edd
4 changed files with 58 additions and 24 deletions

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@ -1,4 +1,5 @@
#include <sys/time.h> #include <sys/time.h>
#include <cstdlib>
#include <filesystem> #include <filesystem>
#include <atomic> #include <atomic>
@ -106,6 +107,24 @@ Path canonPath(PathView path, bool resolveSymlinks)
return s.empty() ? "/" : std::move(s); return s.empty() ? "/" : std::move(s);
} }
Path realPath(Path const & path)
{
// With nullptr, realpath() malloc's and returns a new c-string.
char * resolved = realpath(path.c_str(), nullptr);
int saved = errno;
if (resolved == nullptr) {
throw SysError(saved, "cannot get realpath for '%s'", path);
}
Finally const _free([&] { free(resolved); });
// There's not really a from_raw_parts() for std::string.
// The copy is not a big deal.
Path ret(resolved);
return ret;
}
void chmodPath(const Path & path, mode_t mode) void chmodPath(const Path & path, mode_t mode)
{ {
if (chmod(path.c_str(), mode) == -1) if (chmod(path.c_str(), mode) == -1)

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@ -46,6 +46,22 @@ Path absPath(Path path,
*/ */
Path canonPath(PathView path, bool resolveSymlinks = false); Path canonPath(PathView path, bool resolveSymlinks = false);
/**
* Resolves a file path to a fully absolute path with no symbolic links.
*
* @param path The path to resolve. If it is relative, it will be resolved relative
* to the process's current directory.
*
* @note This is not a pure function; it performs this resolution by querying
* the filesystem.
*
* @note @ref path sadly must be (a reference to) an owned string, as std::string_view
* are not valid C strings...
*
* @return The fully resolved path.
*/
Path realPath(Path const & path);
/** /**
* Change the permissions of a path * Change the permissions of a path
* Not called `chmod` as it shadows and could be confused with * Not called `chmod` as it shadows and could be confused with

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@ -97,12 +97,19 @@ struct CmdUpgradeNix : MixDryRun, EvalCommand
store->ensurePath(storePath); store->ensurePath(storePath);
} }
// {profileDir}/bin/nix-env is a symlink to {profileDir}/bin/nix, which *then*
// is a symlink to /nix/store/meow-nix/bin/nix.
// We want /nix/store/meow-nix/bin/nix-env.
Path const oldNixInStore = realPath(canonProfileDir + "/bin/nix");
Path const oldNixEnv = dirOf(oldNixInStore) + "/nix-env";
Path const newNixEnv = store->printStorePath(storePath) + "/bin/nix-env";
{ {
Activity act(*logger, lvlInfo, actUnknown, fmt("verifying that '%s' works...", store->printStorePath(storePath))); Activity act(*logger, lvlInfo, actUnknown, fmt("verifying that '%s' works...", store->printStorePath(storePath)));
auto program = store->printStorePath(storePath) + "/bin/nix-env"; auto s = runProgram(newNixEnv, false, {"--version"});
auto s = runProgram(program, false, {"--version"});
if (s.find("Nix") == std::string::npos) if (s.find("Nix") == std::string::npos)
throw Error("could not verify that '%s' works", program); throw Error("could not verify that '%s' works", newNixEnv);
} }
logger->pause(); logger->pause();
@ -110,23 +117,17 @@ struct CmdUpgradeNix : MixDryRun, EvalCommand
auto const fullStorePath = store->printStorePath(storePath); auto const fullStorePath = store->printStorePath(storePath);
if (pathExists(canonProfileDir + "/manifest.nix")) { if (pathExists(canonProfileDir + "/manifest.nix")) {
// First remove the existing Nix, then use the *new* Nix by absolute path to
// {settings.nixBinDir}/nix-env is a symlink to a {settings.nixBinDir}/nix, which *then*
// is a symlink to /nix/store/meow-nix/bin/nix. We want /nix/store/meow-nix/bin/nix-env.
Path const nixInStore = canonPath(settings.nixBinDir + "/nix-env", true);
Path const nixEnvCmd = dirOf(nixInStore) + "/nix-env";
// First remove the existing Nix, then use that Nix by absolute path to
// install the new one, in case the new and old versions aren't considered // install the new one, in case the new and old versions aren't considered
// to be "the same package" by nix-env's logic (e.g., if their pnames differ). // to be "the same package" by nix-env's logic (e.g., if their pnames differ).
Strings removeArgs = { Strings removeArgs = {
"--uninstall", "--uninstall",
nixEnvCmd, oldNixEnv,
"--profile", "--profile",
this->profileDir, this->profileDir,
}; };
printTalkative("running %s %s", nixEnvCmd, concatStringsSep(" ", removeArgs)); printTalkative("running %s %s", newNixEnv, concatStringsSep(" ", removeArgs));
runProgram(nixEnvCmd, false, removeArgs); runProgram(newNixEnv, false, removeArgs);
Strings upgradeArgs = { Strings upgradeArgs = {
"--profile", "--profile",
@ -136,8 +137,8 @@ struct CmdUpgradeNix : MixDryRun, EvalCommand
"--no-sandbox", "--no-sandbox",
}; };
printTalkative("running %s %s", nixEnvCmd, concatStringsSep(" ", upgradeArgs)); printTalkative("running %s %s", newNixEnv, concatStringsSep(" ", upgradeArgs));
runProgram(nixEnvCmd, false, upgradeArgs); runProgram(newNixEnv, false, upgradeArgs);
} else if (pathExists(canonProfileDir + "/manifest.json")) { } else if (pathExists(canonProfileDir + "/manifest.json")) {
this->upgradeNewStyleProfile(store, storePath); this->upgradeNewStyleProfile(store, storePath);
} else { } else {

View file

@ -35,9 +35,8 @@ in {
machine.succeed("nix --version >&2") machine.succeed("nix --version >&2")
# Install Lix into the default profile, overriding /run/current-system/sw/bin/nix, # Use Lix to install CppNix into the default profile, overriding /run/current-system/sw/bin/nix
# and thus making Lix think we're not on NixOS. machine.succeed("nix-env --install '${lib.getBin newNix}' --profile /nix/var/nix/profiles/default")
machine.succeed("nix-env --install '${lib.getBin lix}' --profile /nix/var/nix/profiles/default >&2")
# Make sure that correctly got inserted into our PATH. # Make sure that correctly got inserted into our PATH.
default_profile_nix_path = machine.succeed("command -v nix") default_profile_nix_path = machine.succeed("command -v nix")
@ -45,16 +44,15 @@ in {
assert default_profile_nix_path.strip() == "/nix/var/nix/profiles/default/bin/nix", \ assert default_profile_nix_path.strip() == "/nix/var/nix/profiles/default/bin/nix", \
f"{default_profile_nix_path.strip()=} != /nix/var/nix/profiles/default/bin/nix" f"{default_profile_nix_path.strip()=} != /nix/var/nix/profiles/default/bin/nix"
# And that it's the Nix we specified. # And that it's the Nix we specified
default_profile_version = machine.succeed("nix --version") default_profile_version = machine.succeed("nix --version")
assert "${lixVersion}" in default_profile_version, f"${lixVersion} not in {default_profile_version}" assert "${newNixVersion}" in default_profile_version, f"${newNixVersion} not in {default_profile_version}"
# Upgrade to a different version of Nix, and make sure that also worked. # Now upgrade to Lix, and make sure that worked.
machine.succeed("${lib.getExe lix} upgrade-nix --debug --store-path ${lix} 2>&1")
machine.succeed("nix upgrade-nix --store-path ${newNix} >&2")
default_profile_version = machine.succeed("nix --version") default_profile_version = machine.succeed("nix --version")
print(default_profile_version) print(default_profile_version)
assert "${newNixVersion}" in default_profile_version, f"${newNixVersion} not in {default_profile_version}" assert "${lixVersion}" in default_profile_version, f"${lixVersion} not in {default_profile_version}"
# Now 'break' this profile -- use nix profile on it so nix-env will no longer work on it. # Now 'break' this profile -- use nix profile on it so nix-env will no longer work on it.
machine.succeed( machine.succeed(