#include "archive.hh"
#include <dirent.h>
#include <fcntl.h>
#include <strings.h> // for strcasecmp
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <cerrno>
#include <map>
#include <vector>
#include "config.hh"
#include "util.hh"
namespace nix {
struct ArchiveSettings : Config {
Setting<bool> useCaseHack {
this,
#if __APPLE__
true,
#else
false,
#endif
"use-case-hack",
"Whether to enable a Darwin-specific hack for dealing with file name "
"collisions."
};
};
static ArchiveSettings archiveSettings;
static GlobalConfig::Register r1(&archiveSettings);
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);
std::vector<unsigned char> buf(65536);
size_t left = size;
while (left > 0) {
auto n = std::min(left, buf.size());
readFull(fd.get(), buf.data(), n);
left -= n;
sink(buf.data(), 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 (archiveSettings.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;
std::vector<unsigned char> buf(65536);
while (left) {
checkInterrupt();
auto n = buf.size();
if ((unsigned long long)n > left) n = left;
source(buf.data(), n);
sink.receiveContents(buf.data(), 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 (archiveSettings.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, narVersionMagic1.size());
} 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 && errno != EOPNOTSUPP && errno != ENOSYS)
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);
}
void copyNAR(Source& source, Sink& sink) {
// FIXME: if 'source' is the output of dumpPath() followed by EOF,
// we should just forward all data directly without parsing.
ParseSink parseSink; /* null sink; just parse the NAR */
LambdaSource wrapper([&](unsigned char* data, size_t len) {
auto n = source.read(data, len);
sink(data, n);
return n;
});
parseDump(parseSink, wrapper);
}
} // namespace nix
