501 lines
20 KiB
C++
501 lines
20 KiB
C++
#include "container.hpp"
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <algorithm>
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#include <cstdio>
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#include <cctype>
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#include <ctime>
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#include <map>
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#include <sstream>
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#include "spec.hpp"
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#include "util.hpp"
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namespace fs = std::filesystem;
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namespace doos {
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namespace {
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std::string slug(std::string_view hostDir) {
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std::string s(hostDir);
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if (!s.empty() && s.front() == '/') s.erase(0, 1);
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return s;
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}
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std::map<std::string, std::string> parseKv(const std::string& text) {
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std::map<std::string, std::string> kv;
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std::istringstream in(text);
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for (std::string line; std::getline(in, line);) {
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auto eq = line.find('=');
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if (eq != std::string::npos) kv[line.substr(0, eq)] = line.substr(eq + 1);
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}
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return kv;
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}
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// starttime (field 22 of /proc/PID/stat), used to defeat pid reuse.
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std::optional<std::string> startTime(pid_t pid) {
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try {
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std::string st = fsutil::readFile("/proc/" + std::to_string(pid) + "/stat");
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auto rp = st.rfind(')');
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if (rp == std::string::npos) return std::nullopt;
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std::istringstream in(st.substr(rp + 2));
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std::string tok;
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for (int i = 3; i <= 22; ++i) {
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if (!(in >> tok)) return std::nullopt;
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}
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return tok;
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} catch (const std::exception&) {
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return std::nullopt;
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}
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}
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} // namespace
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void Container::validateName(const std::string& name) {
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bool ok = !name.empty() && name.size() <= spec::kMaxNameLen &&
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(std::islower(static_cast<unsigned char>(name[0])) || std::isdigit(static_cast<unsigned char>(name[0])));
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for (char c : name) {
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ok = ok && (std::islower(static_cast<unsigned char>(c)) || std::isdigit(static_cast<unsigned char>(c)) ||
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c == '-' || c == '_');
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}
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if (!ok) {
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throw std::runtime_error("invalid container name '" + name + "': use [a-z0-9][a-z0-9_-]{0,31}");
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}
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}
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fs::path Container::layer(const std::string& hostDir) const { return dir_ / "layers" / slug(hostDir); }
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fs::path Container::privateDir(const std::string& hostDir) const { return dir_ / "private" / slug(hostDir); }
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fs::path Container::etcDir() const {
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return imageMode() ? layer("/root") / "upper" / "etc" : privateDir("/etc");
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}
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void Container::seed(const std::string& marker, const std::string& label,
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const std::function<fsutil::SeedStats()>& work) const {
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fs::path m = dir_ / ("seeded." + marker);
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if (fs::exists(m)) return;
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fsutil::SeedStats st = work();
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std::fprintf(stderr, "doos: seeded %s: %zu entries%s%s\n", label.c_str(), st.made,
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st.skipped ? ", unreadable skipped: " : "", st.skipped ? std::to_string(st.skipped).c_str() : "");
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fsutil::writeFile(m, "ok\n");
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}
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namespace {
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// Names that may hold credentials are never copied, even inside allowed directories.
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bool etcDenied(const fs::path& p) {
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std::string n = p.filename().string();
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if (n.size() > 4 && n.compare(n.size() - 4, 4, ".key") == 0) return true;
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for (auto d : spec::kEtcDenyNames) {
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std::string pat(d);
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if (!pat.empty() && pat.back() == '*') {
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if (n.rfind(pat.substr(0, pat.size() - 1), 0) == 0) return true;
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} else if (n == pat) {
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return true;
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}
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}
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return false;
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}
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} // namespace
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void Container::prepareLayout() const {
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fsutil::mkdirs(rootfs());
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if (imageMode()) {
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fsutil::mkdirs(layer("/root") / "upper");
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fsutil::mkdirs(layer("/root") / "work");
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return;
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}
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std::vector<std::string> overlays;
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auto addOverlay = [&](std::string_view d) {
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std::string dir(d);
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fsutil::mkdirs(layer(dir) / "upper");
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fsutil::mkdirs(layer(dir) / "work");
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overlays.push_back(dir);
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};
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for (auto d : spec::kOverlayDirs) {
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fsutil::mkdirs(rootfs() / slug(d));
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addOverlay(d);
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}
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for (auto d : spec::kCompatDirs) {
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std::error_code ec;
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if (fs::is_directory(fs::symlink_status(std::string(d), ec)) && !ec) {
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fsutil::mkdirs(rootfs() / slug(d));
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addOverlay(d);
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}
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}
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for (auto d : spec::kPrivateDirs) {
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fsutil::mkdirs(rootfs() / slug(d));
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fsutil::mkdirs(privateDir(std::string(d)), 0755);
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}
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for (auto d : spec::kVarDirs) fsutil::mkdirs(privateDir("/var") / d.path, d.mode);
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for (auto d : spec::kVarOverlayDirs) {
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std::error_code ec;
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if (!fs::is_directory(std::string(d), ec)) continue;
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fsutil::mkdirs(privateDir("/var") / std::string(d).substr(5)); // below /var
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addOverlay(d);
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}
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for (auto d : spec::kEmptyDirs) fsutil::mkdirs(rootfs() / slug(d));
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// Host dirs are owned by an unmapped uid (nobody) in the container: without a directory skeleton in the
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// upper layer nothing could ever be created in them (package installs, tool caches).
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for (const auto& o : overlays) {
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std::error_code ec;
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if (!fs::is_directory(o, ec)) continue;
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std::string key = slug(o);
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std::replace(key.begin(), key.end(), '/', '_');
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seed("skeleton-" + key, "directory skeleton " + o, [&] { return fsutil::mirrorDirs(o, layer(o) / "upper"); });
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}
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for (auto d : spec::kUpperCopyDirs) {
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for (const auto& o : overlays) {
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if (std::string(d) != o && std::string(d).rfind(o + "/", 0) != 0) continue;
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std::string rel = std::string(d).substr(o.size());
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std::string key = slug(d);
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std::replace(key.begin(), key.end(), '/', '_');
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fs::path target = layer(o) / "upper" / (rel.empty() ? "" : rel.substr(1));
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std::error_code ec;
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if (!fs::is_directory(std::string(d), ec) || !fs::is_directory(target, ec)) continue;
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seed("files-" + key, "files of " + std::string(d), [&] { return fsutil::copyFiles(std::string(d), target); });
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}
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}
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for (auto f : spec::kUpperLockFiles) {
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for (const auto& o : overlays) {
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if (std::string(f).rfind(o + "/", 0) != 0) continue;
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fs::path target = layer(o) / "upper" / std::string(f).substr(o.size() + 1);
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std::error_code ec;
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if (!fs::is_directory(target.parent_path(), ec) || fs::exists(target, ec)) continue;
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fsutil::writeFile(target, "");
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::chmod(target.c_str(), 0640);
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}
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}
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for (auto d : spec::kCopiedDirs) {
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std::error_code ec;
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if (!fs::is_directory(std::string(d), ec)) continue;
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std::string key = slug(d);
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std::replace(key.begin(), key.end(), '/', '_');
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if (relaxed_) {
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seed("copy-" + key, "copy of " + std::string(d) + " (relaxed)",
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[&] { return fsutil::copyTree(std::string(d), privateDir(std::string(d))); });
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} else {
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seed("copy-" + key, "allowlisted " + std::string(d), [&] {
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std::vector<std::string> names(spec::kEtcAllow.begin(), spec::kEtcAllow.end());
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return fsutil::copyEntries(std::string(d), privateDir(std::string(d)), names, etcDenied);
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});
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}
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}
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}
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namespace {
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void findUppers(const fs::path& dir, std::size_t depth, std::vector<fs::path>& out) {
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std::error_code ec;
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if (depth > 6) return;
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for (const auto& e : fs::directory_iterator(dir, ec)) {
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if (!e.is_directory(ec) || e.is_symlink(ec)) continue;
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std::string n = e.path().filename().string();
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if (n == "upper") out.push_back(e.path());
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else if (n != "work") findUppers(e.path(), depth + 1, out);
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}
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}
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} // namespace
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std::uint64_t Container::usedBytes(std::size_t& skipped) const {
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std::vector<fs::path> dirs;
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std::error_code ec;
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if (fs::exists(dir_ / "layers", ec)) findUppers(dir_ / "layers", 0, dirs);
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if (fs::exists(dir_ / "private", ec)) dirs.push_back(dir_ / "private");
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auto scan = [&](std::size_t& sk) {
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std::uint64_t total = 0;
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for (const auto& d : dirs) total += fsutil::diskUsage(d, sk);
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return total;
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};
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if (ids_ == IdMode::Single) return scan(skipped);
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// Files of other container ids (host uids 100000+) and their mode 700 directories are invisible to the host
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// user; measuring as root of the id map sees them.
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int p[2];
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if (::pipe2(p, O_CLOEXEC) != 0) throw SysError("pipe");
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Fd rd(p[0]), wr(p[1]);
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int rc = UserNsJob::run(ids_, [&] {
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std::size_t sk = 0;
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std::uint64_t t = scan(sk);
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::dprintf(wr.get(), "%llu %zu\n", static_cast<unsigned long long>(t), sk);
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return 0;
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});
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wr.reset();
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if (rc != 0) throw std::runtime_error("size scan failed");
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char buf[64] = {0};
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if (::read(rd.get(), buf, sizeof buf - 1) <= 0) throw std::runtime_error("size scan returned nothing");
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unsigned long long t = 0;
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std::size_t sk = 0;
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std::sscanf(buf, "%llu %zu", &t, &sk);
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skipped += sk;
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return t;
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}
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void Container::writeMeta() const {
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fsutil::writeFile(metaFile(), "net=" + Network::name(net_) + "\ncreated=" + std::to_string(created_) +
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"\nversion=" DOOS_VERSION "\nimage=" + image_ + "\nids=" + IdMap::name(ids_) +
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"\nsize=" + std::to_string(size_) + "\nmemory=" + std::to_string(memory_) +
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"\npids=" + std::to_string(pids_) + "\ncpus=" + std::to_string(milliCpus_) +
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"\nhardening=" + (relaxed_ ? "relaxed" : "default") + "\n");
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}
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void Container::setSizeCap(std::uint64_t bytes) {
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if (bytes < spec::kMinSizeBytes || bytes > spec::kMaxSizeBytes) {
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throw std::runtime_error("size must be between " + formatSize(spec::kMinSizeBytes) + " and " +
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formatSize(spec::kMaxSizeBytes));
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}
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size_ = bytes;
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writeMeta();
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}
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void Container::setLimits(std::optional<std::uint64_t> memory, std::optional<std::uint32_t> pids,
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std::optional<std::uint32_t> milliCpus) {
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if (memory) {
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if (*memory < spec::kMinMemoryBytes || *memory > spec::kMaxMemoryBytes) {
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throw std::runtime_error("memory must be between " + formatSize(spec::kMinMemoryBytes) + " and " +
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formatSize(spec::kMaxMemoryBytes));
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}
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memory_ = *memory;
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}
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if (pids) {
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if (*pids < spec::kMinPids || *pids > spec::kMaxPids) {
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throw std::runtime_error("pids must be between " + std::to_string(spec::kMinPids) + " and " +
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std::to_string(spec::kMaxPids));
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}
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pids_ = *pids;
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}
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if (milliCpus) {
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if (*milliCpus != 0 && (*milliCpus < spec::kMinMilliCpus || *milliCpus > spec::kMaxMilliCpus)) {
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throw std::runtime_error("cpus must be between 0.1 and 1024 (0 = all cores)");
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}
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milliCpus_ = *milliCpus;
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}
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writeMeta();
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}
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void Container::create(const NetMode& net, const std::string& image, IdMode ids, const Options& o) {
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net_ = net;
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image_ = image;
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ids_ = ids;
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size_ = o.size.value_or(spec::kDefaultSizeBytes);
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relaxed_ = o.relaxed.value_or(false);
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memory_ = spec::kDefaultMemoryBytes;
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pids_ = spec::kDefaultPids;
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milliCpus_ = 0;
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if (o.memory || o.pids || o.milliCpus) setLimits(o.memory, o.pids, o.milliCpus);
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created_ = std::time(nullptr);
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fsutil::mkdirs(dir_);
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prepareLayout();
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writeMeta();
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}
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void Container::load() {
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readMeta();
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prepareLayout();
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}
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void Container::readMeta() {
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auto kv = parseKv(fsutil::readFile(metaFile()));
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net_ = Network::parse(kv.count("net") ? kv["net"] : "slirp");
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created_ = kv.count("created") ? std::stol(kv["created"]) : 0;
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image_ = kv.count("image") ? kv["image"] : "";
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ids_ = IdMap::parse(kv.count("ids") ? kv["ids"] : "single");
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size_ = kv.count("size") ? std::stoull(kv["size"]) : spec::kDefaultSizeBytes;
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memory_ = kv.count("memory") ? std::stoull(kv["memory"]) : spec::kDefaultMemoryBytes;
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pids_ = kv.count("pids") ? static_cast<std::uint32_t>(std::stoul(kv["pids"])) : spec::kDefaultPids;
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milliCpus_ = kv.count("cpus") ? static_cast<std::uint32_t>(std::stoul(kv["cpus"])) : 0;
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relaxed_ = kv.count("hardening") && kv["hardening"] == "relaxed";
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}
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std::optional<pid_t> Container::runningPid() const {
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try {
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std::istringstream in(fsutil::readFile(pidFile()));
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long pid = 0;
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std::string start;
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if (!(in >> pid >> start) || pid <= 1) return std::nullopt;
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auto now = startTime(static_cast<pid_t>(pid));
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if (now && *now == start) return static_cast<pid_t>(pid);
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} catch (const std::exception&) {
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}
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return std::nullopt;
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}
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void Container::recordPid(pid_t pid) const {
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auto st = startTime(pid);
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if (!st) throw std::runtime_error("container init exited before it could be recorded");
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fsutil::writeFile(pidFile(), std::to_string(pid) + " " + *st + "\n");
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}
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void Container::clearPid() const {
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std::error_code ec;
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fs::remove(pidFile(), ec);
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}
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Store::Store(fs::path root) : root_(std::move(root)) {
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std::string r = root_.string();
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if (r.find_first_of(",:") != std::string::npos) {
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throw std::runtime_error("state path must not contain ',' or ':' (overlayfs option syntax): " + r);
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}
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fsutil::mkdirs(containersDir(), 0700);
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}
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Store Store::fromEnvironment() {
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if (const char* h = std::getenv("DOOS_HOME"); h && *h) return Store(h);
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if (const char* x = std::getenv("XDG_DATA_HOME"); x && *x) return Store(fs::path(x) / "doos");
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const char* home = std::getenv("HOME");
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if (!home || !*home) throw std::runtime_error("HOME is not set; set DOOS_HOME");
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return Store(fs::path(home) / ".local/share/doos");
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}
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std::vector<Container> Store::list() const {
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std::vector<Container> out;
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for (const auto& e : fs::directory_iterator(containersDir())) {
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if (!e.is_directory() || e.is_symlink()) continue;
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std::string name = e.path().filename().string();
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try {
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Container::validateName(name);
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Container c(e.path(), name);
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c.readMeta();
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out.push_back(std::move(c));
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} catch (const std::exception& ex) {
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std::fprintf(stderr, "doos: skipping %s: %s\n", name.c_str(), ex.what());
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}
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if (out.size() >= spec::kMaxContainers) break;
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}
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std::sort(out.begin(), out.end(), [](const Container& a, const Container& b) { return a.name() < b.name(); });
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return out;
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}
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std::vector<std::string> Store::containersUsing(const std::string& image) const {
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std::vector<std::string> out;
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for (const auto& c : list()) {
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if (c.image() == image) out.push_back(c.name());
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}
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return out;
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}
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std::pair<Container, bool> Store::getOrCreate(const std::string& name, const Options& opts) {
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Container::validateName(name);
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fs::path dir = containersDir() / name;
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Container c(dir, name);
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std::error_code ec;
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std::optional<std::string> image;
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if (opts.image && !opts.image->empty()) image = ImageStore::normalize(*opts.image);
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auto verifyExisting = [&] {
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auto fixed = [&](const char* what, const std::string& have, const std::string& want) {
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if (have != want) {
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throw std::runtime_error("container '" + name + "' exists with " + what + "=" + have +
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"; this is fixed at creation");
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}
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};
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if (opts.net) fixed("net", Network::name(c.net()), Network::name(*opts.net));
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if (image) fixed("image", c.image().empty() ? "none" : c.image(), *image);
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if (opts.ids) fixed("ids", IdMap::name(c.ids()), IdMap::name(*opts.ids));
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if (opts.relaxed) fixed("hardening", c.relaxed() ? "relaxed" : "default", *opts.relaxed ? "relaxed" : "default");
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if (opts.size && *opts.size != c.sizeCap()) c.setSizeCap(*opts.size);
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if (opts.memory || opts.pids || opts.milliCpus) c.setLimits(opts.memory, opts.pids, opts.milliCpus);
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};
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if (fs::exists(dir / "meta", ec)) {
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FileLock lock(c.lockFile(), spec::kLockTimeoutMs);
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c.load();
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verifyExisting();
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return {c, false};
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}
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std::size_t count = 0;
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for (const auto& e : fs::directory_iterator(containersDir())) count += e.is_directory() ? 1 : 0;
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if (count >= spec::kMaxContainers) {
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throw std::runtime_error("container limit reached (" + std::to_string(spec::kMaxContainers) +
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"); delete one first");
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}
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// Resolve the image first (may download); ids follow the image so the layer ownership matches.
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IdMode ids = opts.ids.value_or(IdMap::best());
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if (image) {
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ImageStore store = images();
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if (!store.has(*image)) {
|
|
if (!Catalog::knows(*image)) {
|
|
throw std::runtime_error("unknown image '" + *image + "'. Add it: doos image add SOURCE [NAME] (catalog: alpine, ubuntu, debian)");
|
|
}
|
|
std::fprintf(stderr, "doos: image '%s' not present, fetching it\n", image->c_str());
|
|
store.add(Catalog::resolve(*image), ids);
|
|
}
|
|
IdMode imageIds = store.ids(*image);
|
|
if (opts.ids && *opts.ids != imageIds) {
|
|
throw std::runtime_error("image '" + *image + "' was extracted with ids=" + IdMap::name(imageIds) +
|
|
"; use the same, or add the image again under another name");
|
|
}
|
|
ids = imageIds;
|
|
}
|
|
std::uint64_t size = opts.size.value_or(spec::kDefaultSizeBytes);
|
|
if (size < spec::kMinSizeBytes || size > spec::kMaxSizeBytes) {
|
|
throw std::runtime_error("size must be between " + formatSize(spec::kMinSizeBytes) + " and " +
|
|
formatSize(spec::kMaxSizeBytes));
|
|
}
|
|
fsutil::mkdirs(dir, 0700);
|
|
FileLock lock(c.lockFile(), spec::kLockTimeoutMs);
|
|
if (fs::exists(dir / "meta", ec)) { // lost a creation race
|
|
c.load();
|
|
verifyExisting();
|
|
return {c, false};
|
|
}
|
|
Options resolved = opts;
|
|
resolved.size = size;
|
|
try {
|
|
c.create(opts.net.value_or(NetMode::Slirp), image.value_or(""), ids, resolved);
|
|
} catch (...) {
|
|
// a container that failed halfway must not stay behind as an unreadable directory
|
|
try {
|
|
if (ids == IdMode::Subuid) UserNsJob::run(ids, [&] { fsutil::removeTree(dir); return 0; });
|
|
else fsutil::removeTree(dir);
|
|
} catch (...) {
|
|
}
|
|
throw;
|
|
}
|
|
if (c.net() == NetMode::Host) {
|
|
std::fprintf(stderr, "doos: note: --net host shares the host's abstract unix sockets and loopback; "
|
|
"--net pasta gives the same reachability in a private namespace\n");
|
|
}
|
|
return {c, true};
|
|
}
|
|
|
|
std::string Store::remove(const std::string& name, bool confirmed) {
|
|
Container::validateName(name);
|
|
fs::path dir = containersDir() / name;
|
|
std::error_code ec;
|
|
auto st = fs::symlink_status(dir, ec);
|
|
if (ec || !fs::is_directory(st)) throw std::runtime_error("no such container '" + name + "'");
|
|
if (fs::canonical(dir).parent_path() != fs::canonical(containersDir())) {
|
|
throw std::runtime_error("refusing to delete outside the container store: " + dir.string());
|
|
}
|
|
Container c(dir, name);
|
|
FileLock lock(c.lockFile(), spec::kLockTimeoutMs);
|
|
if (auto pid = c.runningPid()) {
|
|
throw std::runtime_error("container '" + name + "' is running (pid " + std::to_string(*pid) + ")");
|
|
}
|
|
if (!confirmed) {
|
|
std::size_t n = fsutil::countEntries(dir, 1000000);
|
|
return "dry run: would delete " + dir.string() + " (" + std::to_string(n) + " entries). Add --yes to confirm.";
|
|
}
|
|
IdMode ids = IdMode::Single;
|
|
try {
|
|
c.readMeta();
|
|
ids = c.ids();
|
|
} catch (const std::exception&) {
|
|
// damaged or half-created container: remove as plain user, files may be left behind loudly
|
|
}
|
|
if (ids == IdMode::Subuid) {
|
|
// files owned by subuids can only be removed from inside the id map
|
|
int rc = UserNsJob::run(ids, [&] { fsutil::removeTree(dir); return 0; });
|
|
if (rc != 0) throw std::runtime_error("could not remove all files of '" + name + "'");
|
|
} else {
|
|
fsutil::removeTree(dir);
|
|
}
|
|
return "deleted " + name;
|
|
}
|
|
|
|
} // namespace doos
|