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authorLudovic Courtès <ludo@gnu.org>2014-12-17 23:00:42 +0100
committerLudovic Courtès <ludo@gnu.org>2014-12-19 22:47:37 +0100
commit36457566f9917dc7c0c348d012816a2ca333ef1b (patch)
tree6f1d22a195ea2483b9ce539227d65e8e2a9c137d /nix/libutil/archive.cc
parent2c7ee1672029aa43afb509af5b5f7261244fa2d1 (diff)
downloadgnu-guix-36457566f9917dc7c0c348d012816a2ca333ef1b.tar
gnu-guix-36457566f9917dc7c0c348d012816a2ca333ef1b.tar.gz
Merge branch 'nix' into 'master'.
Diffstat (limited to 'nix/libutil/archive.cc')
-rw-r--r--nix/libutil/archive.cc335
1 files changed, 335 insertions, 0 deletions
diff --git a/nix/libutil/archive.cc b/nix/libutil/archive.cc
new file mode 100644
index 0000000000..ab4cd47351
--- /dev/null
+++ b/nix/libutil/archive.cc
@@ -0,0 +1,335 @@
+#include "config.h"
+
+#include <cerrno>
+#include <algorithm>
+#include <vector>
+
+#define _XOPEN_SOURCE 600
+#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";
+
+
+PathFilter defaultPathFilter;
+
+
+static void dump(const string & path, Sink & sink, PathFilter & filter);
+
+
+static void dumpEntries(const Path & path, Sink & sink, PathFilter & filter)
+{
+ Strings names = readDirectory(path);
+ vector<string> names2(names.begin(), names.end());
+ sort(names2.begin(), names2.end());
+
+ for (vector<string>::iterator i = names2.begin();
+ i != names2.end(); ++i)
+ {
+ Path entry = path + "/" + *i;
+ if (filter(entry)) {
+ writeString("entry", sink);
+ writeString("(", sink);
+ writeString("name", sink);
+ writeString(*i, sink);
+ writeString("node", sink);
+ dump(entry, sink, filter);
+ writeString(")", sink);
+ }
+ }
+}
+
+
+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);
+ dumpEntries(path, sink, filter);
+ }
+
+ 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 unknown 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);
+}
+
+
+static void skipGeneric(Source & source)
+{
+ if (readString(source) == "(") {
+ while (readString(source) != ")")
+ skipGeneric(source);
+ }
+}
+
+
+static void parse(ParseSink & sink, Source & source, const Path & path);
+
+
+
+static void parseEntry(ParseSink & sink, Source & source, const Path & path)
+{
+ string s, name;
+
+ 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);
+ } else if (s == "node") {
+ if (s == "") throw badArchive("entry name missing");
+ parse(sink, source, path + "/" + name);
+ } else {
+ throw badArchive("unknown field " + s);
+ skipGeneric(source);
+ }
+ }
+}
+
+
+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);
+}
+
+
+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;
+
+ 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) {
+ parseEntry(sink, source, path);
+ }
+
+ else if (s == "target" && type == tpSymlink) {
+ string target = readString(source);
+ sink.createSymlink(path, target);
+ }
+
+ else {
+ throw badArchive("unknown field " + s);
+ skipGeneric(source);
+ }
+ }
+}
+
+
+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);
+}
+
+
+}