From 3498e9b26a2da46282705791679aa26565a30e99 Mon Sep 17 00:00:00 2001
From: Jake Hillion <jake@hillion.co.uk>
Date: Thu, 30 Dec 2021 20:31:52 +0000
Subject: [PATCH] wip: cloning fs namespace

---
 assertions/Makefile                  |  25 +++++--
 assertions/namespaces/fs/TestClone.c | 100 +++++++++++++++++++++++++++
 2 files changed, 118 insertions(+), 7 deletions(-)
 create mode 100644 assertions/namespaces/fs/TestClone.c

diff --git a/assertions/Makefile b/assertions/Makefile
index f19e21b..4028483 100644
--- a/assertions/Makefile
+++ b/assertions/Makefile
@@ -8,20 +8,31 @@ CFLAGS  = -std=c17
 
 INC_DIRS=-I$(UNITY_ROOT)/src
 
-SRC_NAMESPACES_FS_1=$(UNITY_ROOT)/src/unity.c namespaces/fs/TestUnshare.c test_runners/namespaces_fs_TestUnshare_Runner.c
-TARGET_NAMESPACES_FS_1=target/test_namespaces_fs
+SRC_NAMESPACES_FS_UNSHARE=$(UNITY_ROOT)/src/unity.c namespaces/fs/TestUnshare.c test_runners/namespaces_fs_TestUnshare_Runner.c
+SRC_NAMESPACES_FS_CLONE=$(UNITY_ROOT)/src/unity.c namespaces/fs/TestClone.c test_runners/namespaces_fs_TestClone_Runner.c
+
+TARGET_NAMESPACES_FS_UNSHARE=target/test_namespaces_fs_unshare
+TARGET_NAMESPACES_FS_CLONE=target/test_namespaces_fs_clone
 
 all: clean default
 
-default: $(TARGET_NAMESPACES_FS_1)
-	- ./$(TARGET_NAMESPACES_FS_1)
+default: $(SRC_NAMESPACES_FS_UNSHARE) $(SRC_NAMESPACES_FS_CLONE)
+	$(C_COMPILER) $(CFLAGS) $(INC_DIRS) $(SYMBOLS) $(SRC_NAMESPACES_FS_UNSHARE) -o $(TARGET_NAMESPACES_FS_UNSHARE)
+	$(C_COMPILER) $(CFLAGS) $(INC_DIRS) $(SYMBOLS) $(SRC_NAMESPACES_FS_CLONE) -o $(TARGET_NAMESPACES_FS_CLONE)
 
-$(TARGET_NAMESPACES_FS_1): $(SRC_NAMESPACES_FS_1)
-	$(C_COMPILER) $(CFLAGS) $(INC_DIRS) $(SYMBOLS) $(SRC_NAMESPACES_FS_1) -o $(TARGET_NAMESPACES_FS_1)
+	@echo
+	@echo Finished preparing tests, running now.
+	@echo
+
+	- ./$(TARGET_NAMESPACES_FS_UNSHARE)
+	- ./$(TARGET_NAMESPACES_FS_CLONE)
 
 test_runners/namespaces_fs_TestUnshare_Runner.c: namespaces/fs/TestUnshare.c
 	ruby $(UNITY_ROOT)/auto/generate_test_runner.rb namespaces/fs/TestUnshare.c test_runners/namespaces_fs_TestUnshare_Runner.c
 
+test_runners/namespaces_fs_TestClone_Runner.c: namespaces/fs/TestClone.c
+	ruby $(UNITY_ROOT)/auto/generate_test_runner.rb namespaces/fs/TestClone.c test_runners/namespaces_fs_TestClone_Runner.c
+
 clean:
-	$(CLEANUP) $(TARGET_NAMESPACES_FS_1)
+	$(CLEANUP) $(TARGET_NAMESPACES_FS_UNSHARE) $(TARGET_NAMESPACES_FS_CLONE)
 	mkdir -p test_runners/ target/
diff --git a/assertions/namespaces/fs/TestClone.c b/assertions/namespaces/fs/TestClone.c
new file mode 100644
index 0000000..40a0e5d
--- /dev/null
+++ b/assertions/namespaces/fs/TestClone.c
@@ -0,0 +1,100 @@
+#define _GNU_SOURCE
+
+#include "unity.h"
+
+#include <fcntl.h>
+#include <linux/sched.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <linux/wait.h>
+
+#define CHILD_STACK_SIZE (8 * 1024 * 1024)
+
+#define FILE_DEFAULT_NS ("/tmp/file_exists_0148c163-5919-4651")
+#define FILE_NEW_NS ("/tmp/file_exists_fd0fd491-9816-442d")
+
+void createFile(const char *fname) {
+  int fd = open(fname, O_RDONLY | O_CREAT, 0644);
+  TEST_ASSERT_GREATER_THAN_MESSAGE(0, fd, "open failed");
+  TEST_ASSERT_EQUAL_MESSAGE(0, close(fd), "close failed");
+}
+
+void deleteFileIfExists(const char *fname) {
+  if (access(fname, F_OK) == 0) {
+    TEST_ASSERT_EQUAL_MESSAGE(0, unlink(fname), "unlink failed");
+  }
+}
+
+void setUp(void) { createFile(FILE_DEFAULT_NS); }
+
+void tearDown(void) { deleteFileIfExists(FILE_DEFAULT_NS); }
+
+long clone3(struct clone_args *cl_args) {
+  return syscall(SYS_clone3, cl_args, sizeof(struct clone_args));
+}
+
+void test_cloneFs_findsFileWhenFsCloned_succeeds(void) {
+  // PREPARE
+
+  // ACT
+  pid_t forkedChildPid;
+
+  if ((forkedChildPid = fork()) == 0) {
+    // child process - act but do not assert
+    // all assertions will be on the return code
+    int clonedChildPidFd;
+
+    struct clone_args cl_args = {
+        .flags = CLONE_PIDFD | CLONE_FS,
+        .pidfd = (uint64_t)(&clonedChildPidFd),
+        .child_tid = 0,
+        .parent_tid = 0,
+        .exit_signal = 0,
+        .stack = 0,
+        .stack_size = 0,
+        .tls = 0,
+        .set_tid = 0,
+        .set_tid_size = 0,
+        .cgroup = 0,
+    };
+
+    long cloneResult = clone3(&cl_args);
+    if (cloneResult == 0) {
+      printf("child\n");
+      sleep(30);
+
+      exit(0);
+    } else if (cloneResult == -1) {
+      exit(1); // clone failed
+    }
+
+    sleep(30);
+    siginfo_t status;
+    printf("clonedChildPidFd: %d\n", clonedChildPidFd);
+    if (waitid(P_PIDFD, clonedChildPidFd, &status, WEXITED) == -1) {
+      perror("waitid");
+      exit(2); // wait failed
+    }
+
+    // MUST exit this process and not return
+    // else the test runner will be duplicated
+
+    exit(status.si_status); // propogate return status
+  }
+
+  // ASSERT
+  TEST_ASSERT_GREATER_THAN_MESSAGE(0, forkedChildPid, "fork failed");
+
+  int status = 0;
+  TEST_ASSERT_EQUAL_MESSAGE(forkedChildPid, waitpid(forkedChildPid, &status, 0),
+                            "wait failed");
+  TEST_ASSERT_EQUAL_MESSAGE(0, WEXITSTATUS(status), "return status non-zero");
+}