Mirror of GNU Guix
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#define _XOPEN_SOURCE 600
#include "config.h"
#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 {
static string archiveVersion1 = "nix-archive-1";
static string caseHackSuffix = "~nix~case~hack~";
PathFilter defaultPathFilter;
static void dumpContents(const Path & path, size_t size,
Sink & sink)
{
writeString("contents", sink);
writeLongLong(size, sink);
AutoCloseFD fd = open(path.c_str(), O_RDONLY);
if (fd == -1) 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, buf, n);
left -= n;
sink(buf, n);
}
writePadding(size, sink);
}
static void dump(const Path & path, Sink & sink, PathFilter & filter)
{
struct stat st;
if (lstat(path.c_str(), &st))
throw SysError(format("getting attributes of path `%1%'") % path);
writeString("(", sink);
if (S_ISREG(st.st_mode)) {
writeString("type", sink);
writeString("regular", sink);
if (st.st_mode & S_IXUSR) {
writeString("executable", sink);
writeString("", sink);
}
dumpContents(path, (size_t) st.st_size, sink);
}
else if (S_ISDIR(st.st_mode)) {
writeString("type", sink);
writeString("directory", sink);
/* If we're on a case-insensitive system like Mac OS X, undo
the case hack applied by restorePath(). */
std::map<string, string> unhacked;
for (auto & i : readDirectory(path))
unhacked[i.name] = i.name;
for (auto & i : unhacked)
if (filter(path + "/" + i.first)) {
writeString("entry", sink);
writeString("(", sink);
writeString("name", sink);
writeString(i.first, sink);
writeString("node", sink);
dump(path + "/" + i.second, sink, filter);
writeString(")", sink);
}
}
else if (S_ISLNK(st.st_mode)) {
writeString("type", sink);
writeString("symlink", sink);
writeString("target", sink);
writeString(readLink(path), sink);
}
else throw Error(format("file `%1%' has an unsupported type") % path);
writeString(")", sink);
}
void dumpPath(const Path & path, Sink & sink, PathFilter & filter)
{
writeString(archiveVersion1, sink);
dump(path, sink, filter);
}
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) {
readString(source);
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;
} 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 != archiveVersion1)
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.close();
fd = open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666);
if (fd == -1) throw SysError(format("creating file `%1%'") % p);
}
void isExecutable()
{
struct stat st;
if (fstat(fd, &st) == -1)
throw SysError("fstat");
if (fchmod(fd, 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, 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, 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);
}
}