forked from lix-project/lix
337 lines
7.9 KiB
C++
337 lines
7.9 KiB
C++
#include "config.h"
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#include <cerrno>
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#include <algorithm>
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#include <vector>
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#define _XOPEN_SOURCE 600
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include "archive.hh"
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#include "util.hh"
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namespace nix {
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static string archiveVersion1 = "nix-archive-1";
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PathFilter defaultPathFilter;
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static void dump(const string & path, Sink & sink, PathFilter & filter);
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static void dumpEntries(const Path & path, Sink & sink, PathFilter & filter)
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{
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Strings names = readDirectory(path);
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vector<string> names2(names.begin(), names.end());
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sort(names2.begin(), names2.end());
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for (vector<string>::iterator i = names2.begin();
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i != names2.end(); ++i)
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{
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Path entry = path + "/" + *i;
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if (filter(entry)) {
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writeString("entry", sink);
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writeString("(", sink);
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writeString("name", sink);
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writeString(*i, sink);
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writeString("node", sink);
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dump(entry, sink, filter);
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writeString(")", sink);
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}
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}
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}
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static void dumpContents(const Path & path, size_t size,
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Sink & sink)
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{
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writeString("contents", sink);
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writeLongLong(size, sink);
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AutoCloseFD fd = open(path.c_str(), O_RDONLY);
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if (fd == -1) throw SysError(format("opening file `%1%'") % path);
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unsigned char buf[65536];
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size_t left = size;
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while (left > 0) {
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size_t n = left > sizeof(buf) ? sizeof(buf) : left;
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readFull(fd, buf, n);
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left -= n;
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sink(buf, n);
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}
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writePadding(size, sink);
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}
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static void dump(const Path & path, Sink & sink, PathFilter & filter)
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{
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struct stat st;
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if (lstat(path.c_str(), &st))
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throw SysError(format("getting attributes of path `%1%'") % path);
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writeString("(", sink);
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if (S_ISREG(st.st_mode)) {
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writeString("type", sink);
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writeString("regular", sink);
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if (st.st_mode & S_IXUSR) {
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writeString("executable", sink);
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writeString("", sink);
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}
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dumpContents(path, (size_t) st.st_size, sink);
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}
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else if (S_ISDIR(st.st_mode)) {
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writeString("type", sink);
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writeString("directory", sink);
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dumpEntries(path, sink, filter);
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}
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else if (S_ISLNK(st.st_mode)) {
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writeString("type", sink);
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writeString("symlink", sink);
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writeString("target", sink);
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writeString(readLink(path), sink);
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}
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else throw Error(format("file `%1%' has an unknown type") % path);
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writeString(")", sink);
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}
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void dumpPath(const Path & path, Sink & sink, PathFilter & filter)
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{
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writeString(archiveVersion1, sink);
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dump(path, sink, filter);
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}
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static SerialisationError badArchive(string s)
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{
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return SerialisationError("bad archive: " + s);
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}
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static void skipGeneric(Source & source)
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{
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if (readString(source) == "(") {
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while (readString(source) != ")")
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skipGeneric(source);
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}
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}
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static void parse(ParseSink & sink, Source & source, const Path & path);
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static void parseEntry(ParseSink & sink, Source & source, const Path & path)
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{
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string s, name;
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s = readString(source);
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if (s != "(") throw badArchive("expected open tag");
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while (1) {
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checkInterrupt();
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s = readString(source);
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if (s == ")") {
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break;
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} else if (s == "name") {
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name = readString(source);
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} else if (s == "node") {
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if (s == "") throw badArchive("entry name missing");
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parse(sink, source, path + "/" + name);
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} else {
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throw badArchive("unknown field " + s);
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skipGeneric(source);
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}
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}
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}
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static void parseContents(ParseSink & sink, Source & source, const Path & path)
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{
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unsigned long long size = readLongLong(source);
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sink.preallocateContents(size);
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unsigned long long left = size;
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unsigned char buf[65536];
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while (left) {
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checkInterrupt();
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unsigned int n = sizeof(buf);
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if ((unsigned long long) n > left) n = left;
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source(buf, n);
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sink.receiveContents(buf, n);
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left -= n;
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}
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readPadding(size, source);
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}
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static void parse(ParseSink & sink, Source & source, const Path & path)
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{
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string s;
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s = readString(source);
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if (s != "(") throw badArchive("expected open tag");
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enum { tpUnknown, tpRegular, tpDirectory, tpSymlink } type = tpUnknown;
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while (1) {
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checkInterrupt();
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s = readString(source);
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if (s == ")") {
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break;
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}
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else if (s == "type") {
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if (type != tpUnknown)
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throw badArchive("multiple type fields");
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string t = readString(source);
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if (t == "regular") {
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type = tpRegular;
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sink.createRegularFile(path);
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}
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else if (t == "directory") {
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sink.createDirectory(path);
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type = tpDirectory;
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}
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else if (t == "symlink") {
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type = tpSymlink;
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}
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else throw badArchive("unknown file type " + t);
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}
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else if (s == "contents" && type == tpRegular) {
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parseContents(sink, source, path);
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}
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else if (s == "executable" && type == tpRegular) {
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readString(source);
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sink.isExecutable();
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}
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else if (s == "entry" && type == tpDirectory) {
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parseEntry(sink, source, path);
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}
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else if (s == "target" && type == tpSymlink) {
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string target = readString(source);
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sink.createSymlink(path, target);
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}
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else {
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throw badArchive("unknown field " + s);
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skipGeneric(source);
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}
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}
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}
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void parseDump(ParseSink & sink, Source & source)
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{
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string version;
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try {
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version = readString(source);
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} catch (SerialisationError & e) {
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/* This generally means the integer at the start couldn't be
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decoded. Ignore and throw the exception below. */
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}
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if (version != archiveVersion1)
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throw badArchive("input doesn't look like a Nix archive");
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parse(sink, source, "");
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}
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struct RestoreSink : ParseSink
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{
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Path dstPath;
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AutoCloseFD fd;
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void createDirectory(const Path & path)
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{
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Path p = dstPath + path;
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if (mkdir(p.c_str(), 0777) == -1)
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throw SysError(format("creating directory `%1%'") % p);
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};
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void createRegularFile(const Path & path)
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{
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Path p = dstPath + path;
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fd.close();
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fd = open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666);
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if (fd == -1) throw SysError(format("creating file `%1%'") % p);
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}
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void isExecutable()
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{
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struct stat st;
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if (fstat(fd, &st) == -1)
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throw SysError("fstat");
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if (fchmod(fd, st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1)
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throw SysError("fchmod");
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}
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void preallocateContents(unsigned long long len)
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{
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#if HAVE_POSIX_FALLOCATE
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if (len) {
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errno = posix_fallocate(fd, 0, len);
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/* Note that EINVAL may indicate that the underlying
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filesystem doesn't support preallocation (e.g. on
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OpenSolaris). Since preallocation is just an
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optimisation, ignore it. */
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if (errno && errno != EINVAL)
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throw SysError(format("preallocating file of %1% bytes") % len);
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}
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#endif
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}
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void receiveContents(unsigned char * data, unsigned int len)
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{
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writeFull(fd, data, len);
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}
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void createSymlink(const Path & path, const string & target)
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{
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Path p = dstPath + path;
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if (symlink(target.c_str(), p.c_str()) == -1)
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throw SysError(format("creating symlink `%1%'") % p);
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}
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};
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void restorePath(const Path & path, Source & source)
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{
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RestoreSink sink;
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sink.dstPath = path;
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parseDump(sink, source);
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}
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}
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