362 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			362 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
#define _XOPEN_SOURCE 600
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#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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#include <map>
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#include <strings.h> // for strcasecmp
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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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bool useCaseHack =
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#if __APPLE__
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    true;
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#else
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    false;
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#endif
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static string archiveVersion1 = "nix-archive-1";
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static string caseHackSuffix = "~nix~case~hack~";
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PathFilter defaultPathFilter;
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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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        /* If we're on a case-insensitive system like Mac OS X, undo
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           the case hack applied by restorePath(). */
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        std::map<string, string> unhacked;
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        for (auto & i : readDirectory(path))
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            if (useCaseHack) {
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                string name(i.name);
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                size_t pos = i.name.find(caseHackSuffix);
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                if (pos != string::npos) {
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                    printMsg(lvlDebug, format("removing case hack suffix from `%1%'") % (path + "/" + i.name));
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                    name.erase(pos);
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                }
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                if (unhacked.find(name) != unhacked.end())
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                    throw Error(format("file name collision in between `%1%' and `%2%'")
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                        % (path + "/" + unhacked[name]) % (path + "/" + i.name));
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                unhacked[name] = i.name;
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            } else
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                unhacked[i.name] = i.name;
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        for (auto & i : unhacked)
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            if (filter(path + "/" + i.first)) {
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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.first, sink);
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                writeString("node", sink);
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                dump(path + "/" + i.second, sink, filter);
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                writeString(")", sink);
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            }
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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 unsupported 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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#if 0
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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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#endif
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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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struct CaseInsensitiveCompare
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{
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    bool operator() (const string & a, const string & b) const
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    {
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        return strcasecmp(a.c_str(), b.c_str()) < 0;
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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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{
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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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    std::map<Path, int, CaseInsensitiveCompare> names;
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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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            string name, prevName;
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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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                    if (name.empty() || name == "." || name == ".." || name.find('/') != string::npos || name.find((char) 0) != string::npos)
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                        throw Error(format("NAR contains invalid file name `%1%'") % name);
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                    if (name <= prevName)
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                        throw Error("NAR directory is not sorted");
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                    prevName = name;
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                    if (useCaseHack) {
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                        auto i = names.find(name);
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                        if (i != names.end()) {
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                            printMsg(lvlDebug, format("case collision between `%1%' and `%2%'") % i->first % name);
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                            name += caseHackSuffix;
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                            name += std::to_string(++i->second);
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                        } else
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                            names[name] = 0;
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                    }
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                } else if (s == "node") {
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                    if (s.empty()) 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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            }
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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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    }
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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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        nix::createSymlink(target, 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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