#include <regex>
#include <absl/strings/ascii.h>
#include <absl/strings/str_split.h>
#include <fcntl.h>
#include <pwd.h>
#include "libmain/shared.hh"
#include "libstore/download.hh"
#include "libstore/globals.hh"
#include "libstore/store-api.hh"
#include "nix/legacy.hh"
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);
std::vector<std::string> lines =
absl::StrSplit(channelsFile, absl::ByChar('\n'));
for (auto& line : lines) {
line = absl::StripTrailingAsciiWhitespace(line);
if (std::regex_search(line, std::regex("^\\s*\\#"))) {
continue;
}
std::vector<std::string> split = absl::StrSplit(line, absl::ByChar(' '));
auto url = std::regex_replace(split[0], std::regex("/*$"), "");
auto name = split.size() > 1 ? split[1] : baseNameOf(url);
channels[name] = url;
}
}
// Writes the list of channels.
static void writeChannels() {
auto channelsFD = AutoCloseFD{open(
channelsList.c_str(), O_WRONLY | O_CLOEXEC | O_CREAT | O_TRUNC, 0644)};
if (!channelsFD) {
throw SysError(format("opening '%1%' for writing") % channelsList);
}
for (const auto& channel : channels) {
writeFull(channelsFD.get(), channel.second + " " + channel.first + "\n");
}
}
// Adds a channel.
static void addChannel(const std::string& url, const std::string& name) {
if (!regex_search(url, std::regex("^(file|http|https)://"))) {
throw Error(format("invalid channel URL '%1%'") % url);
}
if (!regex_search(name, std::regex("^[a-zA-Z0-9_][a-zA-Z0-9_\\.-]*$"))) {
throw Error(format("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();
// Download each channel.
Strings exprs;
for (const auto& channel : channels) {
auto name = channel.first;
auto url = channel.second;
if (!(channelNames.empty() || (channelNames.count(name) != 0u))) {
continue;
}
// 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.
CachedDownloadRequest request(url);
request.ttl = 0;
auto dl = getDownloader();
auto result = dl->downloadCached(store, request);
auto filename = result.path;
url = absl::StripTrailingAsciiWhitespace(result.effectiveUri);
// 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 = baseNameOf(url);
if (std::regex_search(urlBase, match, std::regex("(-\\d.*)$"))) {
cname = cname + (std::string)match[1];
}
std::string extraAttrs;
bool unpacked = false;
if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) {
runProgram(settings.nixBinDir + "/nix-build", false,
{"--no-out-link", "--expr",
"import <nix/unpack-channel.nix> "
"{ name = \"" +
cname + "\"; channelName = \"" + name +
"\"; src = builtins.storePath \"" + filename + "\"; }"});
unpacked = true;
}
if (!unpacked) {
// Download the channel tarball.
try {
filename = dl->downloadCached(
store, CachedDownloadRequest(url + "/nixexprs.tar.xz"))
.path;
} catch (DownloadError& e) {
filename =
dl->downloadCached(store,
CachedDownloadRequest(url + "/nixexprs.tar.bz2"))
.path;
}
filename = absl::StripTrailingAsciiWhitespace(filename);
}
// 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", "<nix/unpack-channel.nix>",
"--install", "--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(format("unlinking %1%") % nixDefExpr);
}
}
} else if (errno != ENOENT) {
throw SysError(format("getting status of %1%") % nixDefExpr);
}
createDirs(nixDefExpr);
auto channelLink = nixDefExpr + "/channels";
replaceSymlink(profile, channelLink);
}
static int _main(int argc, char** argv) {
{
// Figure out the name of the `.nix-channels' file to use
auto home = getHome();
channelsList = home + "/.nix-channels";
nixDefExpr = home + "/.nix-defexpr";
// Figure out the name of the channels profile.
profile = fmt("%s/profiles/per-user/%s/channels", settings.nixStateDir,
getUserName());
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 {
args.push_back(std::move(*arg));
}
return true;
});
switch (cmd) {
case cNone:
throw UsageError("no command specified");
case cAdd:
if (args.empty() || 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 s1("nix-channel", _main);
