#include <cerrno> #include <algorithm> #include <vector> #include <map> #include <strings.h> // for strcasecmp #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <dirent.h> #include <fcntl.h> #include "archive.hh" #include "util.hh" namespace nix { bool useCaseHack = #if __APPLE__ true; #else false; #endif const std::string narVersionMagic1 = "nix-archive-1"; static string caseHackSuffix = "~nix~case~hack~"; PathFilter defaultPathFilter = [](const Path &) { return true; }; static void dumpContents(const Path & path, size_t size, Sink & sink) { sink << "contents" << size; AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_CLOEXEC); if (!fd) throw SysError(format("opening file '%1%'") % path); unsigned char buf[65536]; size_t left = size; while (left > 0) { size_t n = left > sizeof(buf) ? sizeof(buf) : left; readFull(fd.get(), buf, n); left -= n; sink(buf, n); } writePadding(size, sink); } static void dump(const Path & path, Sink & sink, PathFilter & filter) { checkInterrupt(); struct stat st; if (lstat(path.c_str(), &st)) throw SysError(format("getting attributes of path '%1%'") % path); sink << "("; if (S_ISREG(st.st_mode)) { sink << "type" << "regular"; if (st.st_mode & S_IXUSR) sink << "executable" << ""; dumpContents(path, (size_t) st.st_size, sink); } else if (S_ISDIR(st.st_mode)) { sink << "type" << "directory"; /* If we're on a case-insensitive system like macOS, undo the case hack applied by restorePath(). */ std::map<string, string> unhacked; for (auto & i : readDirectory(path)) if (useCaseHack) { string name(i.name); size_t pos = i.name.find(caseHackSuffix); if (pos != string::npos) { debug(format("removing case hack suffix from '%1%'") % (path + "/" + i.name)); name.erase(pos); } if (unhacked.find(name) != unhacked.end()) throw Error(format("file name collision in between '%1%' and '%2%'") % (path + "/" + unhacked[name]) % (path + "/" + i.name)); unhacked[name] = i.name; } else unhacked[i.name] = i.name; for (auto & i : unhacked) if (filter(path + "/" + i.first)) { sink << "entry" << "(" << "name" << i.first << "node"; dump(path + "/" + i.second, sink, filter); sink << ")"; } } else if (S_ISLNK(st.st_mode)) sink << "type" << "symlink" << "target" << readLink(path); else throw Error(format("file '%1%' has an unsupported type") % path); sink << ")"; } void dumpPath(const Path & path, Sink & sink, PathFilter & filter) { sink << narVersionMagic1; dump(path, sink, filter); } void dumpString(const std::string & s, Sink & sink) { sink << narVersionMagic1 << "(" << "type" << "regular" << "contents" << s << ")"; } static SerialisationError badArchive(string s) { return SerialisationError("bad archive: " + s); } #if 0 static void skipGeneric(Source & source) { if (readString(source) == "(") { while (readString(source) != ")") skipGeneric(source); } } #endif static void parseContents(ParseSink & sink, Source & source, const Path & path) { unsigned long long size = readLongLong(source); sink.preallocateContents(size); unsigned long long left = size; unsigned char buf[65536]; while (left) { checkInterrupt(); unsigned int n = sizeof(buf); if ((unsigned long long) n > left) n = left; source(buf, n); sink.receiveContents(buf, n); left -= n; } readPadding(size, source); } struct CaseInsensitiveCompare { bool operator() (const string & a, const string & b) const { return strcasecmp(a.c_str(), b.c_str()) < 0; } }; static void parse(ParseSink & sink, Source & source, const Path & path) { string s; s = readString(source); if (s != "(") throw badArchive("expected open tag"); enum { tpUnknown, tpRegular, tpDirectory, tpSymlink } type = tpUnknown; std::map<Path, int, CaseInsensitiveCompare> names; while (1) { checkInterrupt(); s = readString(source); if (s == ")") { break; } else if (s == "type") { if (type != tpUnknown) throw badArchive("multiple type fields"); string t = readString(source); if (t == "regular") { type = tpRegular; sink.createRegularFile(path); } else if (t == "directory") { sink.createDirectory(path); type = tpDirectory; } else if (t == "symlink") { type = tpSymlink; } else throw badArchive("unknown file type " + t); } else if (s == "contents" && type == tpRegular) { parseContents(sink, source, path); } else if (s == "executable" && type == tpRegular) { auto s = readString(source); if (s != "") throw badArchive("executable marker has non-empty value"); sink.isExecutable(); } else if (s == "entry" && type == tpDirectory) { string name, prevName; s = readString(source); if (s != "(") throw badArchive("expected open tag"); while (1) { checkInterrupt(); s = readString(source); if (s == ")") { break; } else if (s == "name") { name = readString(source); if (name.empty() || name == "." || name == ".." || name.find('/') != string::npos || name.find((char) 0) != string::npos) throw Error(format("NAR contains invalid file name '%1%'") % name); if (name <= prevName) throw Error("NAR directory is not sorted"); prevName = name; if (useCaseHack) { auto i = names.find(name); if (i != names.end()) { debug(format("case collision between '%1%' and '%2%'") % i->first % name); name += caseHackSuffix; name += std::to_string(++i->second); } else names[name] = 0; } } else if (s == "node") { if (s.empty()) throw badArchive("entry name missing"); parse(sink, source, path + "/" + name); } else throw badArchive("unknown field " + s); } } else if (s == "target" && type == tpSymlink) { string target = readString(source); sink.createSymlink(path, target); } else throw badArchive("unknown field " + s); } } void parseDump(ParseSink & sink, Source & source) { string version; try { version = readString(source); } catch (SerialisationError & e) { /* This generally means the integer at the start couldn't be decoded. Ignore and throw the exception below. */ } if (version != narVersionMagic1) throw badArchive("input doesn't look like a Nix archive"); parse(sink, source, ""); } struct RestoreSink : ParseSink { Path dstPath; AutoCloseFD fd; void createDirectory(const Path & path) { Path p = dstPath + path; if (mkdir(p.c_str(), 0777) == -1) throw SysError(format("creating directory '%1%'") % p); }; void createRegularFile(const Path & path) { Path p = dstPath + path; fd = open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY | O_CLOEXEC, 0666); if (!fd) throw SysError(format("creating file '%1%'") % p); } void isExecutable() { struct stat st; if (fstat(fd.get(), &st) == -1) throw SysError("fstat"); if (fchmod(fd.get(), st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1) throw SysError("fchmod"); } void preallocateContents(unsigned long long len) { #if HAVE_POSIX_FALLOCATE if (len) { errno = posix_fallocate(fd.get(), 0, len); /* Note that EINVAL may indicate that the underlying filesystem doesn't support preallocation (e.g. on OpenSolaris). Since preallocation is just an optimisation, ignore it. */ if (errno && errno != EINVAL) throw SysError(format("preallocating file of %1% bytes") % len); } #endif } void receiveContents(unsigned char * data, unsigned int len) { writeFull(fd.get(), data, len); } void createSymlink(const Path & path, const string & target) { Path p = dstPath + path; nix::createSymlink(target, p); } }; void restorePath(const Path & path, Source & source) { RestoreSink sink; sink.dstPath = path; parseDump(sink, source); } }