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Clean up libarchive support

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This commit is contained in:
Puck Meerburg 2019-12-07 18:08:33 +00:00
parent fe7ec70e6b
commit 28ee687adf
1 changed files with 83 additions and 90 deletions
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173
src/libutil/tarfile.cc
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@ -6,75 +6,78 @@
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;
struct TarArchive {
struct archive *archive;
Source *source;
unsigned char buffer[4096];
void check(int err, const char *reason = "Failed to extract archive (%s)") {
if (err == ARCHIVE_EOF)
throw EndOfFile("reached end of archive");
else if (err != ARCHIVE_OK)
throw Error(reason, archive_error_string(this->archive));
}
TarArchive(Source& source) {
this->archive = archive_read_new();
this->source = &source;
archive_read_support_filter_all(archive);
archive_read_support_format_all(archive);
check(archive_read_open(archive, (void *)this, TarArchive::callback_open, TarArchive::callback_read, TarArchive::callback_close), "Failed to open archive (%s)");
}
TarArchive(const Path &path) {
this->archive = archive_read_new();
archive_read_support_filter_all(archive);
archive_read_support_format_all(archive);
check(archive_read_open_filename(archive, path.c_str(), 16384), "Failed to open archive (%s)");
}
void close() {
check(archive_read_close(archive), "Failed to close archive (%s)");
}
~TarArchive() {
if (this->archive) archive_read_free(this->archive);
}
private:
static int callback_open(struct archive *, void *self) {
return ARCHIVE_OK;
}
static ssize_t callback_read(struct archive *archive, void *_self, const void **buffer) {
TarArchive *self = (TarArchive *)_self;
*buffer = self->buffer;
try {
return self->source->read(self->buffer, 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;
}
};
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) {
PushD(const 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);
@ -83,51 +86,41 @@ struct PushD {
/* can't throw out of a destructor */
}
};
static void extract_archive(std::shared_ptr<struct archive> a, const Path & destDir) {
static void extract_archive(TarArchive &archive, 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());
int flags = ARCHIVE_EXTRACT_FFLAGS | ARCHIVE_EXTRACT_PERM;
for(;;) {
int r = archive_read_next_header(a.get(), &entry);
int r = archive_read_next_header(archive.archive, &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());
else if (r == ARCHIVE_WARN)
std::cerr << "warning: " << archive_error_string(archive.archive) << std::endl;
else
archive.check(r);
archive.check(archive_read_extract(archive.archive, entry, flags));
}
// 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");
archive.close();
}
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);
auto archive = TarArchive(source);
createDirs(destDir);
extract_archive(a, destDir);
extract_archive(archive, 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));
auto archive = TarArchive(tarFile);
createDirs(destDir);
extract_archive(a, destDir);
extract_archive(archive, destDir);
}
}