lix/src/nix-channel/nix-channel.cc
Alexander Bantyev 2384d36083
A setting to follow XDG Base Directory standard
XDG Base Directory is a standard for locations for storing various
files. Nix has a few files which seem to fit in the standard, but
currently use a custom location directly in the user's ~, polluting
it:

- ~/.nix-profile
- ~/.nix-defexpr
- ~/.nix-channels

This commit adds a config option (use-xdg-base-directories) to follow
the XDG spec and instead use the following locations:

- $XDG_STATE_HOME/nix/profile
- $XDG_STATE_HOME/nix/defexpr
- $XDG_STATE_HOME/nix/channels

If $XDG_STATE_HOME is not set, it is assumed to be ~/.local/state.

Co-authored-by: Théophane Hufschmitt <7226587+thufschmitt@users.noreply.github.com>
Co-authored-by: Tim Fenney <kodekata@gmail.com>
Co-authored-by: pasqui23 <pasqui23@users.noreply.github.com>
Co-authored-by: Artturin <Artturin@artturin.com>
Co-authored-by: John Ericson <Ericson2314@Yahoo.com>
2023-02-10 20:14:06 +04:00

258 lines
9.6 KiB
C++
Executable file

#include "profiles.hh"
#include "shared.hh"
#include "globals.hh"
#include "filetransfer.hh"
#include "store-api.hh"
#include "legacy.hh"
#include "fetchers.hh"
#include "util.hh"
#include <fcntl.h>
#include <regex>
#include <pwd.h>
using namespace nix;
typedef std::map<std::string, std::string> Channels;
static Channels channels;
static Path channelsList;
// Reads the list of channels.
static void readChannels()
{
if (!pathExists(channelsList)) return;
auto channelsFile = readFile(channelsList);
for (const auto & line : tokenizeString<std::vector<std::string>>(channelsFile, "\n")) {
chomp(line);
if (std::regex_search(line, std::regex("^\\s*\\#")))
continue;
auto split = tokenizeString<std::vector<std::string>>(line, " ");
auto url = std::regex_replace(split[0], std::regex("/*$"), "");
auto name = split.size() > 1 ? split[1] : std::string(baseNameOf(url));
channels[name] = url;
}
}
// Writes the list of channels.
static void writeChannels()
{
auto channelsFD = AutoCloseFD{open(channelsList.c_str(), O_WRONLY | O_CLOEXEC | O_CREAT | O_TRUNC, 0644)};
if (!channelsFD)
throw SysError("opening '%1%' for writing", channelsList);
for (const auto & channel : channels)
writeFull(channelsFD.get(), channel.second + " " + channel.first + "\n");
}
// Adds a channel.
static void addChannel(const std::string & url, const std::string & name)
{
if (!regex_search(url, std::regex("^(file|http|https)://")))
throw Error("invalid channel URL '%1%'", url);
if (!regex_search(name, std::regex("^[a-zA-Z0-9_][a-zA-Z0-9_\\.-]*$")))
throw Error("invalid channel identifier '%1%'", name);
readChannels();
channels[name] = url;
writeChannels();
}
static Path profile;
// Remove a channel.
static void removeChannel(const std::string & name)
{
readChannels();
channels.erase(name);
writeChannels();
runProgram(settings.nixBinDir + "/nix-env", true, { "--profile", profile, "--uninstall", name });
}
static Path nixDefExpr;
// Fetch Nix expressions and binary cache URLs from the subscribed channels.
static void update(const StringSet & channelNames)
{
readChannels();
auto store = openStore();
auto [fd, unpackChannelPath] = createTempFile();
writeFull(fd.get(),
#include "unpack-channel.nix.gen.hh"
);
fd = -1;
AutoDelete del(unpackChannelPath, false);
// Download each channel.
Strings exprs;
for (const auto & channel : channels) {
auto name = channel.first;
auto url = channel.second;
// If the URL contains a version number, append it to the name
// attribute (so that "nix-env -q" on the channels profile
// shows something useful).
auto cname = name;
std::smatch match;
auto urlBase = std::string(baseNameOf(url));
if (std::regex_search(urlBase, match, std::regex("(-\\d.*)$")))
cname = cname + match.str(1);
std::string extraAttrs;
if (!(channelNames.empty() || channelNames.count(name))) {
// no need to update this channel, reuse the existing store path
Path symlink = profile + "/" + name;
Path storepath = dirOf(readLink(symlink));
exprs.push_back("f: rec { name = \"" + cname + "\"; type = \"derivation\"; outputs = [\"out\"]; system = \"builtin\"; outPath = builtins.storePath \"" + storepath + "\"; out = { inherit outPath; };}");
} else {
// We want to download the url to a file to see if it's a tarball while also checking if we
// got redirected in the process, so that we can grab the various parts of a nix channel
// definition from a consistent location if the redirect changes mid-download.
auto result = fetchers::downloadFile(store, url, std::string(baseNameOf(url)), false);
auto filename = store->toRealPath(result.storePath);
url = result.effectiveUrl;
bool unpacked = false;
if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) {
runProgram(settings.nixBinDir + "/nix-build", false, { "--no-out-link", "--expr", "import " + unpackChannelPath +
"{ name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; }" });
unpacked = true;
}
if (!unpacked) {
// Download the channel tarball.
try {
filename = store->toRealPath(fetchers::downloadFile(store, url + "/nixexprs.tar.xz", "nixexprs.tar.xz", false).storePath);
} catch (FileTransferError & e) {
filename = store->toRealPath(fetchers::downloadFile(store, url + "/nixexprs.tar.bz2", "nixexprs.tar.bz2", false).storePath);
}
}
// Regardless of where it came from, add the expression representing this channel to accumulated expression
exprs.push_back("f: f { name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; " + extraAttrs + " }");
}
}
// Unpack the channel tarballs into the Nix store and install them
// into the channels profile.
std::cerr << "unpacking channels...\n";
Strings envArgs{ "--profile", profile, "--file", unpackChannelPath, "--install", "--remove-all", "--from-expression" };
for (auto & expr : exprs)
envArgs.push_back(std::move(expr));
envArgs.push_back("--quiet");
runProgram(settings.nixBinDir + "/nix-env", false, envArgs);
// Make the channels appear in nix-env.
struct stat st;
if (lstat(nixDefExpr.c_str(), &st) == 0) {
if (S_ISLNK(st.st_mode))
// old-skool ~/.nix-defexpr
if (unlink(nixDefExpr.c_str()) == -1)
throw SysError("unlinking %1%", nixDefExpr);
} else if (errno != ENOENT) {
throw SysError("getting status of %1%", nixDefExpr);
}
createDirs(nixDefExpr);
auto channelLink = nixDefExpr + "/channels";
replaceSymlink(profile, channelLink);
}
static int main_nix_channel(int argc, char ** argv)
{
{
// Figure out the name of the `.nix-channels' file to use
auto home = getHome();
channelsList = settings.useXDGBaseDirectories ? createNixStateDir() + "/channels" : home + "/.nix-channels";
nixDefExpr = settings.useXDGBaseDirectories ? createNixStateDir() + "/defexpr" : home + "/.nix-defexpr";
// Figure out the name of the channels profile.
profile = profilesDir() + "/channels";
enum {
cNone,
cAdd,
cRemove,
cList,
cUpdate,
cRollback
} cmd = cNone;
std::vector<std::string> args;
parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
if (*arg == "--help") {
showManPage("nix-channel");
} else if (*arg == "--version") {
printVersion("nix-channel");
} else if (*arg == "--add") {
cmd = cAdd;
} else if (*arg == "--remove") {
cmd = cRemove;
} else if (*arg == "--list") {
cmd = cList;
} else if (*arg == "--update") {
cmd = cUpdate;
} else if (*arg == "--rollback") {
cmd = cRollback;
} else {
if (hasPrefix(*arg, "-"))
throw UsageError("unsupported argument '%s'", *arg);
args.push_back(std::move(*arg));
}
return true;
});
switch (cmd) {
case cNone:
throw UsageError("no command specified");
case cAdd:
if (args.size() < 1 || args.size() > 2)
throw UsageError("'--add' requires one or two arguments");
{
auto url = args[0];
std::string name;
if (args.size() == 2) {
name = args[1];
} else {
name = baseNameOf(url);
name = std::regex_replace(name, std::regex("-unstable$"), "");
name = std::regex_replace(name, std::regex("-stable$"), "");
}
addChannel(url, name);
}
break;
case cRemove:
if (args.size() != 1)
throw UsageError("'--remove' requires one argument");
removeChannel(args[0]);
break;
case cList:
if (!args.empty())
throw UsageError("'--list' expects no arguments");
readChannels();
for (const auto & channel : channels)
std::cout << channel.first << ' ' << channel.second << '\n';
break;
case cUpdate:
update(StringSet(args.begin(), args.end()));
break;
case cRollback:
if (args.size() > 1)
throw UsageError("'--rollback' has at most one argument");
Strings envArgs{"--profile", profile};
if (args.size() == 1) {
envArgs.push_back("--switch-generation");
envArgs.push_back(args[0]);
} else {
envArgs.push_back("--rollback");
}
runProgram(settings.nixBinDir + "/nix-env", false, envArgs);
break;
}
return 0;
}
}
static RegisterLegacyCommand r_nix_channel("nix-channel", main_nix_channel);