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Clean up libarchive support

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This commit is contained in:
puck 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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155
src/libutil/tarfile.cc
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@ -6,75 +6,78 @@
namespace nix { namespace nix {
std::shared_ptr<struct archive> archive_read_ptr() { struct TarArchive {
return std::shared_ptr<struct archive>(archive_read_new(), struct archive *archive;
[](auto p) { Source *source;
archive_read_close(p); unsigned char buffer[4096];
archive_read_free(p);
}); void check(int err, const char *reason = "Failed to extract archive (%s)") {
} if (err == ARCHIVE_EOF)
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"); throw EndOfFile("reached end of archive");
else if (err != ARCHIVE_OK)
throw Error(reason, archive_error_string(this->archive));
} }
if (r != ARCHIVE_OK) {
throw Error(str, archive_error_string(a.get())); 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 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); }); void close() {
typedef struct { check(archive_read_close(archive), "Failed to close archive (%s)");
decltype(buffer) buf; }
Source& src;
unsigned int bs; ~TarArchive() {
} St; if (this->archive) archive_read_free(this->archive);
St* state = new St({buffer, s, bufsize}); }
ac(a, archive_read_open(a.get(), state,
NULL /* open */, private:
([] (struct archive*, void* sptr, const void** buf) -> long int { static int callback_open(struct archive *, void *self) {
St& s = *(static_cast<St*>(sptr)); return ARCHIVE_OK;
*buf = s.buf.get(); }
static ssize_t callback_read(struct archive *archive, void *_self, const void **buffer) {
TarArchive *self = (TarArchive *)_self;
*buffer = self->buffer;
try { try {
return s.src.read(s.buf.get(), s.bs); return self->source->read(self->buffer, 4096);
} catch (EndOfFile &) { } catch (EndOfFile &) {
return 0; return 0;
} } catch (std::exception &err) {
/* TODO: I don't know what happens if anything else is thrown here */ archive_set_error(archive, EIO, "Source threw exception: %s", err.what());
}), [] (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 (;;) { return -1;
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)");
} }
} }
static int callback_close(struct archive *, void *self) {
return ARCHIVE_OK;
}
};
struct PushD { struct PushD {
char * oldDir; char * oldDir;
PushD(std::string newDir) {
PushD(const std::string &newDir) {
oldDir = getcwd(0, 0); oldDir = getcwd(0, 0);
if (!oldDir) throw SysError("getcwd"); if (!oldDir) throw SysError("getcwd");
int r = chdir(newDir.c_str()); int r = chdir(newDir.c_str());
if (r != 0) throw SysError("changing directory to tar output path"); if (r != 0) throw SysError("changing directory to tar output path");
} }
~PushD() { ~PushD() {
int r = chdir(oldDir); int r = chdir(oldDir);
free(oldDir); free(oldDir);
@ -83,51 +86,41 @@ struct PushD {
/* can't throw out of a destructor */ /* 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 // need to chdir back *after* archive closing
PushD newDir(destDir); PushD newDir(destDir);
struct archive_entry *entry; struct archive_entry *entry;
int flags = 0; int flags = ARCHIVE_EXTRACT_FFLAGS | ARCHIVE_EXTRACT_PERM;
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(;;) { 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_EOF) break;
if (r == ARCHIVE_WARN) { else if (r == ARCHIVE_WARN)
std::cerr << "warning: " << archive_error_string(a.get()); std::cerr << "warning: " << archive_error_string(archive.archive) << std::endl;
} else if (r < ARCHIVE_WARN) { else
ac(a, r); archive.check(r);
archive.check(archive_read_extract(archive.archive, entry, flags));
} }
ac(ext, archive_write_header(ext.get(), entry), "could not write archive output (%s)");
copy_data(a, ext); archive.close();
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) void unpackTarfile(Source & source, const Path & destDir)
{ {
auto a = nix::archive_read_ptr(); auto archive = TarArchive(source);
archive_read_support_filter_all(a.get());
archive_read_support_format_all(a.get());
nix::archive_read_open_source(a, source);
createDirs(destDir); createDirs(destDir);
extract_archive(a, destDir); extract_archive(archive, destDir);
} }
void unpackTarfile(const Path & tarFile, const Path & destDir) void unpackTarfile(const Path & tarFile, const Path & destDir)
{ {
auto a = nix::archive_read_ptr(); auto archive = TarArchive(tarFile);
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); createDirs(destDir);
extract_archive(a, destDir); extract_archive(archive, destDir);
} }
} }