code 'cleanup'

This commit is contained in:
Yorick van Pelt 2019-12-07 23:23:11 +07:00
parent f54c168031
commit 1355554d12
No known key found for this signature in database
GPG key ID: A36E70F9DC014A15

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@ -20,7 +20,7 @@ std::shared_ptr<struct archive> archive_read_ptr() {
} }
static void ac(std::shared_ptr<struct archive> a, int r, const char* str = "archive is corrupt (%s)") { static void ac(std::shared_ptr<struct archive> a, int r, const char* str = "archive is corrupt (%s)") {
if (r == ARCHIVE_EOF) { if (r == ARCHIVE_EOF) {
throw EndOfFile("tar ended"); throw EndOfFile("reached end of archive");
} }
if (r != ARCHIVE_OK) { if (r != ARCHIVE_OK) {
throw Error(str, archive_error_string(a.get())); throw Error(str, archive_error_string(a.get()));
@ -72,16 +72,25 @@ static void copy_data(std::shared_ptr<struct archive> ar, std::shared_ptr<struct
ac(aw, archive_write_data_block(aw.get(), buff, size, offset), "could not write archive output (%s)"); 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) { static void extract_archive(std::shared_ptr<struct archive> a, const Path & destDir) {
char * cwd = getcwd(0, 0); // need to chdir back *after* archive closing
if (!cwd) throw SysError("getting current directory"); PushD newDir(destDir);
Finally backCwd([&]() {
int r = chdir(cwd);
free(cwd);
if (r != 0) throw SysError("resetting directory after archive extraction");
});
int r = chdir(destDir.c_str());
if (r != 0) throw SysError("setting directory to tar output path");
struct archive_entry *entry; struct archive_entry *entry;
int flags = 0; int flags = 0;
auto ext = archive_write_ptr(); auto ext = archive_write_ptr();
@ -90,7 +99,7 @@ static void extract_archive(std::shared_ptr<struct archive> a, const Path & dest
archive_write_disk_set_options(ext.get(), flags); archive_write_disk_set_options(ext.get(), flags);
archive_write_disk_set_standard_lookup(ext.get()); archive_write_disk_set_standard_lookup(ext.get());
for(;;) { for(;;) {
r = archive_read_next_header(a.get(), &entry); int r = archive_read_next_header(a.get(), &entry);
if (r == ARCHIVE_EOF) break; if (r == ARCHIVE_EOF) break;
if (r == ARCHIVE_WARN) { if (r == ARCHIVE_WARN) {
std::cerr << "warning: " << archive_error_string(a.get()); std::cerr << "warning: " << archive_error_string(a.get());
@ -101,22 +110,27 @@ static void extract_archive(std::shared_ptr<struct archive> a, const Path & dest
copy_data(a, ext); copy_data(a, ext);
archive_write_finish_entry(ext.get()); 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 = archive_read_ptr(); auto a = nix::archive_read_ptr();
archive_read_support_filter_all(a.get()); archive_read_support_filter_all(a.get());
archive_read_support_format_all(a.get()); archive_read_support_format_all(a.get());
archive_read_open_source(a, source); nix::archive_read_open_source(a, source);
createDirs(destDir); createDirs(destDir);
extract_archive(a, destDir); extract_archive(a, destDir);
} }
void unpackTarfile(const Path & tarFile, const Path & destDir) void unpackTarfile(const Path & tarFile, const Path & destDir)
{ {
auto a = archive_read_ptr(); auto a = nix::archive_read_ptr();
archive_read_support_filter_all(a.get()); archive_read_support_filter_all(a.get());
archive_read_support_format_all(a.get()); archive_read_support_format_all(a.get());
ac(a, archive_read_open_filename(a.get(), tarFile.c_str(), 16384)); ac(a, archive_read_open_filename(a.get(), tarFile.c_str(), 16384));
createDirs(destDir); createDirs(destDir);
extract_archive(a, destDir); extract_archive(a, destDir);
} }