bool TPath::HasAccess(const TCred &cred, enum Access mask) const {
struct stat st;
int mode;
if (!cred.Uid && !access(c_str(), mask & TPath::RWX))
return true;
if (stat(c_str(), &st)) {
if (!(mask & TPath::P) || errno != ENOENT)
return false;
TPath dir = DirName();
while (stat(dir.c_str(), &st)) {
if (errno != ENOENT)
return false;
if (dir.Path.size() <= 1)
return false;
dir = dir.DirName();
}
}
if ((mask & TPath::U) && cred.Uid == st.st_uid)
return true;
if (cred.Uid == st.st_uid)
mode = st.st_mode >> 6;
else if (cred.IsMemberOf(st.st_gid))
TError TNamespaceFd::Open(TPath path) {
Close();
Fd = open(path.c_str(), O_RDONLY | O_NOCTTY | O_NONBLOCK | O_CLOEXEC);
if (Fd < 0)
return TError(EError::Unknown, errno, "Cannot open " + path.ToString());
return TError::Success();
}
TError TMount::Find(TPath path, const TPath mounts) {
path = path.NormalPath();
auto device = path.GetDev();
if (!device)
return TError(EError::Unknown, "device not found: " + path.ToString() + ")");
FILE* f = setmntent(mounts.c_str(), "r");
if (!f)
return TError(EError::Unknown, errno, "setmntent(" + mounts.ToString() + ")");
struct mntent* m, mntbuf;
TScopedMem buf(4096);
TError error(EError::Unknown, "mountpoint not found: " + path.ToString() + ")");
while ((m = getmntent_r(f, &mntbuf, (char *)buf.GetData(), buf.GetSize()))) {
TPath source(m->mnt_fsname);
TPath target(m->mnt_dir);
if (target.InnerPath(path).IsEmpty() ||
source.GetBlockDev() != device)
continue;
Source = source;
Target = target;
Type = m->mnt_type;
Data.clear();
error = SplitString(m->mnt_opts, ',', Data);
break;
}
endmntent(f);
return error;
}
TError TMount::Snapshot(std::vector<std::shared_ptr<TMount>> &result, const TPath mounts) {
FILE* f = setmntent(mounts.c_str(), "r");
if (!f)
return TError(EError::Unknown, errno, "setmntent(" + mounts.ToString() + ")");
struct mntent* m, mntbuf;
TScopedMem buf(4096);
while ((m = getmntent_r(f, &mntbuf, (char *)buf.GetData(), buf.GetSize()))) {
vector<string> flags;
TError error = SplitString(m->mnt_opts, ',', flags);
if (error) {
endmntent(f);
return error;
}
result.push_back(std::make_shared<TMount>(m->mnt_fsname, m->mnt_dir, m->mnt_type, flags));
}
endmntent(f);
return TError::Success();
}
TError SetupLoopDevice(TPath image, int &dev)
{
static std::mutex BigLoopLock;
int control_fd, image_fd, loop_nr, loop_fd;
struct loop_info64 info;
std::string loop;
int retry = 10;
TError error;
image_fd = open(image.c_str(), O_RDWR | O_CLOEXEC);
if (image_fd < 0) {
error = TError(EError::Unknown, errno, "open(" + image.ToString() + ")");
goto err_image;
}
control_fd = open("/dev/loop-control", O_RDWR | O_CLOEXEC);
if (control_fd < 0) {
error = TError(EError::Unknown, errno, "open(/dev/loop-control)");
goto err_control;
}
BigLoopLock.lock();
again:
loop_nr = ioctl(control_fd, LOOP_CTL_GET_FREE);
if (loop_nr < 0) {
error = TError(EError::Unknown, errno, "ioctl(LOOP_CTL_GET_FREE)");
goto err_get_free;
}
loop = "/dev/loop" + std::to_string(loop_nr);
loop_fd = open(loop.c_str(), O_RDWR | O_CLOEXEC);
if (loop_fd < 0) {
error = TError(EError::Unknown, errno, "open(" + loop + ")");
goto err_loop_open;
}
if (ioctl(loop_fd, LOOP_SET_FD, image_fd) < 0) {
error = TError(EError::Unknown, errno, "ioctl(LOOP_SET_FD)");
if (errno == EBUSY) {
if (!ioctl(loop_fd, LOOP_GET_STATUS64, &info) || errno == ENXIO) {
if (--retry > 0) {
close(loop_fd);
goto again;
}
}
}
goto err_set_fd;
}
memset(&info, 0, sizeof(info));
strncpy((char *)info.lo_file_name, image.c_str(), LO_NAME_SIZE);
if (ioctl(loop_fd, LOOP_SET_STATUS64, &info) < 0) {
error = TError(EError::Unknown, errno, "ioctl(LOOP_SET_STATUS64)");
ioctl(loop_fd, LOOP_CLR_FD, 0);
goto err_set_status;
}
dev = loop_nr;
error = TError::Success();
err_set_status:
err_set_fd:
close(loop_fd);
err_loop_open:
err_get_free:
BigLoopLock.unlock();
close(control_fd);
err_control:
close(image_fd);
err_image:
return error;
}
TError TMount::Remount(TPath path, unsigned long flags) {
if (mount(NULL, path.c_str(), NULL, flags, NULL))
return TError(EError::Unknown, errno, "mount(NULL, " + path.ToString() + ", NULL, " + std::to_string(flags) + ", NULL)");
return TError::Success();
}