diff options
Diffstat (limited to 'src/nix-channel/nix-channel.cc')
| -rwxr-xr-x | src/nix-channel/nix-channel.cc | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/src/nix-channel/nix-channel.cc b/src/nix-channel/nix-channel.cc new file mode 100755 index 000000000000..0f50f6242c48 --- /dev/null +++ b/src/nix-channel/nix-channel.cc @@ -0,0 +1,267 @@ +#include "shared.hh" +#include "globals.hh" +#include "download.hh" +#include <fcntl.h> +#include <regex> +#include "store-api.hh" +#include <pwd.h> + +using namespace nix; + +typedef std::map<string,string> Channels; + +static auto channels = Channels{}; +static auto channelsList = Path{}; + +// Reads the list of channels. +static void readChannels() +{ + if (!pathExists(channelsList)) return; + auto channelsFile = readFile(channelsList); + + for (const auto & line : tokenizeString<std::vector<string>>(channelsFile, "\n")) { + chomp(line); + if (std::regex_search(line, std::regex("^\\s*\\#"))) + continue; + auto split = tokenizeString<std::vector<string>>(line, " "); + auto url = std::regex_replace(split[0], std::regex("/*$"), ""); + auto name = split.size() > 1 ? split[1] : baseNameOf(url); + channels[name] = url; + } +} + +// Writes the list of channels. +static void writeChannels() +{ + auto channelsFD = AutoCloseFD{open(channelsList.c_str(), O_WRONLY | O_CLOEXEC | O_CREAT | O_TRUNC, 0644)}; + if (!channelsFD) + throw SysError(format("opening ‘%1%’ for writing") % channelsList); + for (const auto & channel : channels) + writeFull(channelsFD.get(), channel.second + " " + channel.first + "\n"); +} + +// Adds a channel. +static void addChannel(const string & url, const string & name) +{ + if (!regex_search(url, std::regex("^(file|http|https)://"))) + throw Error(format("invalid channel URL ‘%1%’") % url); + if (!regex_search(name, std::regex("^[a-zA-Z0-9_][a-zA-Z0-9_\\.-]*$"))) + throw Error(format("invalid channel identifier ‘%1%’") % name); + readChannels(); + channels[name] = url; + writeChannels(); +} + +static auto profile = Path{}; + +// Remove a channel. +static void removeChannel(const string & name) +{ + readChannels(); + channels.erase(name); + writeChannels(); + + runProgram(settings.nixBinDir + "/nix-env", true, { "--profile", profile, "--uninstall", name }); +} + +static auto nixDefExpr = Path{}; + +// Fetch Nix expressions and binary cache URLs from the subscribed channels. +static void update(const StringSet & channelNames) +{ + readChannels(); + + auto store = openStore(); + + // Download each channel. + auto exprs = Strings{}; + for (const auto & channel : channels) { + auto name = channel.first; + auto url = channel.second; + if (!(channelNames.empty() || channelNames.count(name))) + 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. + auto effectiveUrl = string{}; + auto dl = getDownloader(); + auto filename = dl->downloadCached(store, url, false, "", Hash(), &effectiveUrl); + url = chomp(std::move(effectiveUrl)); + + // 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.*)$"))) { + cname = cname + (string) match[1]; + } + + auto extraAttrs = string{}; + + auto unpacked = false; + if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) { + 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) { + // The URL doesn't unpack directly, so let's try treating it like a full channel folder with files in it + // Check if the channel advertises a binary cache. + DownloadRequest request(url + "/binary-cache-url"); + request.showProgress = DownloadRequest::no; + try { + auto dlRes = dl->download(request); + extraAttrs = "binaryCacheURL = \"" + *dlRes.data + "\";"; + } catch (DownloadError & e) { + } + + // Download the channel tarball. + auto fullURL = url + "/nixexprs.tar.xz"; + try { + filename = dl->downloadCached(store, fullURL, false); + } catch (DownloadError & e) { + fullURL = url + "/nixexprs.tar.bz2"; + filename = dl->downloadCached(store, fullURL, false); + } + chomp(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"; + auto envArgs = Strings{ "--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); +} + +int main(int argc, char ** argv) +{ + return handleExceptions(argv[0], [&]() { + initNix(); + + // Turn on caching in nix-prefetch-url. + auto channelCache = settings.nixStateDir + "/channel-cache"; + createDirs(channelCache); + setenv("NIX_DOWNLOAD_CACHE", channelCache.c_str(), 1); + + // Figure out the name of the `.nix-channels' file to use + auto home = getEnv("HOME"); + if (home.empty()) + throw Error("$HOME not set"); + channelsList = home + "/.nix-channels"; + nixDefExpr = home + "/.nix-defexpr"; + + // Figure out the name of the channels profile. + auto name = string{}; + auto pw = getpwuid(getuid()); + if (!pw) + name = getEnv("USER", ""); + else + name = pw->pw_name; + if (name.empty()) + throw Error("cannot figure out user name"); + profile = settings.nixStateDir + "/profiles/per-user/" + name + "/channels"; + createDirs(dirOf(profile)); + + enum { + cNone, + cAdd, + cRemove, + cList, + cUpdate, + cRollback + } cmd = cNone; + auto args = std::vector<string>{}; + parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) { + if (*arg == "--help") { + showManPage("nix-channel"); + } else if (*arg == "--version") { + printVersion("nix-channel"); + } else if (*arg == "--add") { + cmd = cAdd; + } else if (*arg == "--remove") { + cmd = cRemove; + } else if (*arg == "--list") { + cmd = cList; + } else if (*arg == "--update") { + cmd = cUpdate; + } else if (*arg == "--rollback") { + cmd = cRollback; + } else { + args.push_back(std::move(*arg)); + } + return true; + }); + switch (cmd) { + case cNone: + throw UsageError("no command specified"); + case cAdd: + if (args.size() < 1 || args.size() > 2) + throw UsageError("‘--add’ requires one or two arguments"); + { + auto url = args[0]; + auto name = string{}; + if (args.size() == 2) { + name = args[1]; + } else { + name = baseNameOf(url); + name = std::regex_replace(name, std::regex("-unstable$"), ""); + 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"); + auto envArgs = Strings{"--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; + } + }); +} |