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authorYu Jiung <jiung.yu@samsung.com>2016-11-09 02:18:45 (GMT)
committerYu Jiung <jiung.yu@samsung.com>2016-11-09 02:18:55 (GMT)
commiteb886f120599b2a184db20b527db6dfdfcb7852e (patch)
treeb49d8075742c4a27b237fa183cb68670e421d398 /test/ares-test-ns.cc
parentb6627e2c19506bd30328969ea8aab73fa0945f36 (diff)
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Imported Upstream version 1.11.0upstream/1.11.0refs/changes/18/96418/1
Change-Id: I238c24b75a10aa902d9bc4076ed68b76b5e2a750
Diffstat (limited to 'test/ares-test-ns.cc')
-rw-r--r--test/ares-test-ns.cc199
1 files changed, 199 insertions, 0 deletions
diff --git a/test/ares-test-ns.cc b/test/ares-test-ns.cc
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+#include "ares-test.h"
+
+#ifdef HAVE_CONTAINER
+
+#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <iostream>
+#include <functional>
+#include <string>
+#include <sstream>
+#include <vector>
+
+namespace ares {
+namespace test {
+
+namespace {
+
+struct ContainerInfo {
+ ContainerFilesystem* fs_;
+ std::string hostname_;
+ std::string domainname_;
+ VoidToIntFn fn_;
+};
+
+int EnterContainer(void *data) {
+ ContainerInfo *container = (ContainerInfo*)data;
+
+ if (verbose) {
+ std::cerr << "Running function in container {chroot='"
+ << container->fs_->root() << "', hostname='" << container->hostname_
+ << "', domainname='" << container->domainname_ << "'}"
+ << std::endl;
+ }
+
+ // Ensure we are apparently root before continuing.
+ int count = 10;
+ while (getuid() != 0 && count > 0) {
+ usleep(100000);
+ count--;
+ }
+ if (getuid() != 0) {
+ std::cerr << "Child in user namespace has uid " << getuid() << std::endl;
+ return -1;
+ }
+ if (!container->fs_->mountpt().empty()) {
+ // We want to bind mount this inside the specified directory.
+ std::string innerdir = container->fs_->root() + container->fs_->mountpt();
+ if (verbose) std::cerr << " mount --bind " << container->fs_->mountpt()
+ << " " << innerdir << std::endl;
+ int rc = mount(container->fs_->mountpt().c_str(), innerdir.c_str(),
+ "none", MS_BIND, 0);
+ if (rc != 0) {
+ std::cerr << "Warning: failed to bind mount " << container->fs_->mountpt() << " at "
+ << innerdir << ", errno=" << errno << std::endl;
+ }
+ }
+
+ // Move into the specified directory.
+ if (chdir(container->fs_->root().c_str()) != 0) {
+ std::cerr << "Failed to chdir('" << container->fs_->root()
+ << "'), errno=" << errno << std::endl;
+ return -1;
+ }
+ // And make it the new root directory;
+ char buffer[PATH_MAX + 1];
+ if (getcwd(buffer, PATH_MAX) == NULL) {
+ std::cerr << "failed to retrieve cwd, errno=" << errno << std::endl;
+ return -1;
+ }
+ buffer[PATH_MAX] = '\0';
+ if (chroot(buffer) != 0) {
+ std::cerr << "chroot('" << buffer << "') failed, errno=" << errno << std::endl;
+ return -1;
+ }
+
+ // Set host/domainnames if specified
+ if (!container->hostname_.empty()) {
+ if (sethostname(container->hostname_.c_str(),
+ container->hostname_.size()) != 0) {
+ std::cerr << "Failed to sethostname('" << container->hostname_
+ << "'), errno=" << errno << std::endl;
+ return -1;
+ }
+ }
+ if (!container->domainname_.empty()) {
+ if (setdomainname(container->domainname_.c_str(),
+ container->domainname_.size()) != 0) {
+ std::cerr << "Failed to setdomainname('" << container->domainname_
+ << "'), errno=" << errno << std::endl;
+ return -1;
+ }
+ }
+
+ return container->fn_();
+}
+
+} // namespace
+
+// Run a function while:
+// - chroot()ed into a particular directory
+// - having a specified hostname/domainname
+
+int RunInContainer(ContainerFilesystem* fs, const std::string& hostname,
+ const std::string& domainname, VoidToIntFn fn) {
+ const int stack_size = 1024 * 1024;
+ std::vector<byte> stack(stack_size, 0);
+ ContainerInfo container = {fs, hostname, domainname, fn};
+
+ // Start a child process in a new user and UTS namespace
+ pid_t child = clone(EnterContainer, stack.data() + stack_size,
+ CLONE_VM|CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWUTS|SIGCHLD,
+ (void *)&container);
+ if (child < 0) {
+ std::cerr << "Failed to clone(), errno=" << errno << std::endl;
+ return -1;
+ }
+
+ // Build the UID map that makes us look like root inside the namespace.
+ std::stringstream mapfiless;
+ mapfiless << "/proc/" << child << "/uid_map";
+ std::string mapfile = mapfiless.str();
+ int fd = open(mapfile.c_str(), O_CREAT|O_WRONLY|O_TRUNC, 0644);
+ if (fd < 0) {
+ std::cerr << "Failed to create '" << mapfile << "'" << std::endl;
+ return -1;
+ }
+ std::stringstream contentss;
+ contentss << "0 " << getuid() << " 1" << std::endl;
+ std::string content = contentss.str();
+ int rc = write(fd, content.c_str(), content.size());
+ if (rc != (int)content.size()) {
+ std::cerr << "Failed to write uid map to '" << mapfile << "'" << std::endl;
+ }
+ close(fd);
+
+ // Wait for the child process and retrieve its status.
+ int status;
+ waitpid(child, &status, 0);
+ if (rc <= 0) {
+ std::cerr << "Failed to waitpid(" << child << ")" << std::endl;
+ return -1;
+ }
+ if (!WIFEXITED(status)) {
+ std::cerr << "Child " << child << " did not exit normally" << std::endl;
+ return -1;
+ }
+ return status;
+}
+
+ContainerFilesystem::ContainerFilesystem(NameContentList files, const std::string& mountpt) {
+ rootdir_ = TempNam(nullptr, "ares-chroot");
+ mkdir(rootdir_.c_str(), 0755);
+ dirs_.push_front(rootdir_);
+ for (const auto& nc : files) {
+ std::string fullpath = rootdir_ + nc.first;
+ int idx = fullpath.rfind('/');
+ std::string dir = fullpath.substr(0, idx);
+ EnsureDirExists(dir);
+ files_.push_back(std::unique_ptr<TransientFile>(
+ new TransientFile(fullpath, nc.second)));
+ }
+ if (!mountpt.empty()) {
+ char buffer[PATH_MAX + 1];
+ if (realpath(mountpt.c_str(), buffer)) {
+ mountpt_ = buffer;
+ std::string fullpath = rootdir_ + mountpt_;
+ EnsureDirExists(fullpath);
+ }
+ }
+}
+
+ContainerFilesystem::~ContainerFilesystem() {
+ files_.clear();
+ for (const std::string& dir : dirs_) {
+ rmdir(dir.c_str());
+ }
+}
+
+void ContainerFilesystem::EnsureDirExists(const std::string& dir) {
+ if (std::find(dirs_.begin(), dirs_.end(), dir) != dirs_.end()) {
+ return;
+ }
+ size_t idx = dir.rfind('/');
+ if (idx != std::string::npos) {
+ std::string prevdir = dir.substr(0, idx);
+ EnsureDirExists(prevdir);
+ }
+ // Ensure this directory is in the list before its ancestors.
+ mkdir(dir.c_str(), 0755);
+ dirs_.push_front(dir);
+}
+
+} // namespace test
+} // namespace ares
+
+#endif