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#include "rust-ffi.hh"
#include "compression.hh"
#include <archive.h>
#include <archive_entry.h>
#include "finally.hh"
extern "C" {
rust::Result<std::tuple<>> *
unpack_tarfile(rust::Source source, rust::StringSlice dest_dir);
}
namespace nix {
std::shared_ptr<struct archive> archive_read_ptr() {
return std::shared_ptr<struct archive>(archive_read_new(),
[](auto p) {
archive_read_close(p);
archive_read_free(p);
});
}
static void ac(std::shared_ptr<struct archive> a, int r, const char* str = "archive is corrupt (%s)") {
if (r == ARCHIVE_EOF) {
throw EndOfFile("reached end of archive");
}
if (r != ARCHIVE_OK) {
throw Error(str, archive_error_string(a.get()));
}
}
void archive_read_open_source(std::shared_ptr<struct archive> a, Source& s, unsigned int bufsize = 1024) {
std::shared_ptr<unsigned char> buffer((unsigned char*)malloc(bufsize), [](auto p) { free(p); });
typedef struct {
decltype(buffer) buf;
Source& src;
unsigned int bs;
} St;
St* state = new St({buffer, s, bufsize});
ac(a, archive_read_open(a.get(), state,
NULL /* open */,
([] (struct archive*, void* sptr, const void** buf) -> long int {
St& s = *(static_cast<St*>(sptr));
*buf = s.buf.get();
try {
return s.src.read(s.buf.get(), s.bs);
} catch (EndOfFile &) {
return 0;
}
/* TODO: I don't know what happens if anything else is thrown here */
}), [] (struct archive*, void* sptr) {
delete static_cast<St*>(sptr);
return ARCHIVE_OK;
}));
}
std::shared_ptr<struct archive> archive_write_ptr() {
return std::shared_ptr<struct archive>(archive_write_disk_new(),
[](auto p) {
archive_write_close(p);
archive_write_free(p);
});
}
static void copy_data(std::shared_ptr<struct archive> ar, std::shared_ptr<struct archive> aw)
{
const void *buff;
size_t size;
la_int64_t offset;
for (;;) {
try {
ac(ar, archive_read_data_block(ar.get(), &buff, &size, &offset));
} catch (EndOfFile &) {
return;
}
ac(aw, archive_write_data_block(aw.get(), buff, size, offset), "could not write archive output (%s)");
}
}
struct PushD {
char * oldDir;
PushD(std::string newDir) {
oldDir = getcwd(0, 0);
if (!oldDir) throw SysError("getcwd");
int r = chdir(newDir.c_str());
if (r != 0) throw SysError("changing directory to tar output path");
}
~PushD() {
int r = chdir(oldDir);
free(oldDir);
if (r != 0)
std::cerr << "warning: popd failed to chdir";
/* can't throw out of a destructor */
}
};
static void extract_archive(std::shared_ptr<struct archive> a, const Path & destDir) {
// need to chdir back *after* archive closing
PushD newDir(destDir);
struct archive_entry *entry;
int flags = 0;
auto ext = archive_write_ptr();
flags |= ARCHIVE_EXTRACT_PERM;
flags |= ARCHIVE_EXTRACT_FFLAGS;
archive_write_disk_set_options(ext.get(), flags);
archive_write_disk_set_standard_lookup(ext.get());
for(;;) {
int r = archive_read_next_header(a.get(), &entry);
if (r == ARCHIVE_EOF) break;
if (r == ARCHIVE_WARN) {
std::cerr << "warning: " << archive_error_string(a.get());
} else if (r < ARCHIVE_WARN) {
ac(a, r);
}
ac(ext, archive_write_header(ext.get(), entry), "could not write archive output (%s)");
copy_data(a, ext);
archive_write_finish_entry(ext.get());
}
// done in dtor, but this error can be 'failed to set permissions'
// so it's important
ac(ext, archive_write_close(ext.get()), "finishing archive extraction");
}
void unpackTarfile(Source & source, const Path & destDir)
{
auto a = nix::archive_read_ptr();
archive_read_support_filter_all(a.get());
archive_read_support_format_all(a.get());
nix::archive_read_open_source(a, source);
createDirs(destDir);
extract_archive(a, destDir);
}
void unpackTarfile(const Path & tarFile, const Path & destDir)
{
auto a = nix::archive_read_ptr();
archive_read_support_filter_all(a.get());
archive_read_support_format_all(a.get());
ac(a, archive_read_open_filename(a.get(), tarFile.c_str(), 16384));
createDirs(destDir);
extract_archive(a, destDir);
}
}
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