nix-super/src/libutil/tarfile.cc
2021-08-30 17:02:51 +02:00

121 lines
3 KiB
C++

#include <archive.h>
#include <archive_entry.h>
#include "serialise.hh"
#include "tarfile.hh"
namespace nix {
static int callback_open(struct archive *, void * self)
{
return ARCHIVE_OK;
}
static ssize_t callback_read(struct archive * archive, void * _self, const void * * buffer)
{
auto self = (TarArchive *) _self;
*buffer = self->buffer.data();
try {
return self->source->read((char *) self->buffer.data(), 4096);
} catch (EndOfFile &) {
return 0;
} catch (std::exception & err) {
archive_set_error(archive, EIO, "Source threw exception: %s", err.what());
return -1;
}
}
static int callback_close(struct archive *, void * self)
{
return ARCHIVE_OK;
}
void TarArchive::check(int err, const std::string & reason)
{
if (err == ARCHIVE_EOF)
throw EndOfFile("reached end of archive");
else if (err != ARCHIVE_OK)
throw Error(reason, archive_error_string(this->archive));
}
TarArchive::TarArchive(Source & source, bool raw)
: source(&source), buffer(4096)
{
init();
if (!raw)
archive_read_support_format_all(archive);
else
archive_read_support_format_raw(archive);
check(archive_read_open(archive, (void *)this, callback_open, callback_read, callback_close), "Failed to open archive (%s)");
}
TarArchive::TarArchive(const Path & path)
{
init();
archive_read_support_format_all(archive);
check(archive_read_open_filename(archive, path.c_str(), 16384), "failed to open archive: %s");
}
void TarArchive::init()
{
archive = archive_read_new();
archive_read_support_filter_all(archive);
}
void TarArchive::close()
{
check(archive_read_close(this->archive), "Failed to close archive (%s)");
}
TarArchive::~TarArchive()
{
if (this->archive) archive_read_free(this->archive);
}
static void extract_archive(TarArchive & archive, const Path & destDir)
{
int flags = ARCHIVE_EXTRACT_FFLAGS
| ARCHIVE_EXTRACT_PERM
| ARCHIVE_EXTRACT_TIME
| ARCHIVE_EXTRACT_SECURE_SYMLINKS
| ARCHIVE_EXTRACT_SECURE_NODOTDOT;
for (;;) {
struct archive_entry * entry;
int r = archive_read_next_header(archive.archive, &entry);
if (r == ARCHIVE_EOF) break;
auto name = archive_entry_pathname(entry);
if (!name)
throw Error("cannot get archive member name: %s", archive_error_string(archive.archive));
if (r == ARCHIVE_WARN)
warn(archive_error_string(archive.archive));
else
archive.check(r);
archive_entry_set_pathname(entry,
(destDir + "/" + name).c_str());
archive.check(archive_read_extract(archive.archive, entry, flags));
}
archive.close();
}
void unpackTarfile(Source & source, const Path & destDir)
{
auto archive = TarArchive(source);
createDirs(destDir);
extract_archive(archive, destDir);
}
void unpackTarfile(const Path & tarFile, const Path & destDir)
{
auto archive = TarArchive(tarFile);
createDirs(destDir);
extract_archive(archive, destDir);
}
}