diff options
Diffstat (limited to 'third_party/nix/src/nix-channel')
| -rw-r--r-- | third_party/nix/src/nix-channel/nix-channel.cc | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/third_party/nix/src/nix-channel/nix-channel.cc b/third_party/nix/src/nix-channel/nix-channel.cc new file mode 100644 index 000000000000..5cc16d1b4b9a --- /dev/null +++ b/third_party/nix/src/nix-channel/nix-channel.cc @@ -0,0 +1,275 @@ +#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'), absl::SkipEmpty()); + + 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(' '), absl::SkipEmpty()); + 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); |