[PATCH 2/6][cr-tests]: eclone-2: Fail if selected pid is in use

[Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

From: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Date: Sat, 30 Jan 2010 12:51:23 -0800
Subject: [PATCH 2/6]: eclone-2: Fail if selected pid is in use

Ensure that eclone() system call fails with -EBUSY if selected pid is
in use.

Signed-off-by: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
---
 eclone/Makefile   |    2 +-
 eclone/eclone-2.c |  117 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 118 insertions(+), 1 deletions(-)
 create mode 100644 eclone/eclone-2.c

diff --git a/eclone/Makefile b/eclone/Makefile
index 43cef65..95633d1 100644
--- a/eclone/Makefile
+++ b/eclone/Makefile
@@ -3,7 +3,7 @@ CFLAGS = -Wall
 
 LDFLAGS = 
 
-PROGS = eclone-1
+PROGS = eclone-1 eclone-2
 
 all: $(PROGS)
 
diff --git a/eclone/eclone-2.c b/eclone/eclone-2.c
new file mode 100644
index 0000000..a52bb5e
--- /dev/null
+++ b/eclone/eclone-2.c
@@ -0,0 +1,117 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/syscall.h>
+#include "clone_args.h"
+
+/*
+ * Verify that eclone() fails if the selected pid is in use.
+ * We try to assign parent's pid which should already be in use.
+ */
+int verbose = 0;
+int child_tid, parent_tid;
+#define	CHILD_ARG	(void *)0x979797
+
+pid_t pids_list[2];
+
+int do_child(void *arg)
+{
+	printf("FAIL: Child created with [%d, %d], but we expected child "
+			"creation to fail since pid is in use\n", gettid(),
+ 			getpid());
+	exit(2);
+}
+
+static int myclone(int (*child_fn)(void *), void *child_arg, 
+		unsigned int flags_low, int nr_pids, pid_t *pids_list)
+{
+	int rc;
+	void *stack;
+	struct clone_args ca;
+	int args_size;
+
+	stack = setup_stack(child_fn, child_arg, STACKSIZE);
+	if (!stack) {
+		printf("ERROR: setup_stack returns NULL for size %d\n",
+				STACKSIZE);
+		exit(1);
+	}
+
+	memset(&ca, 0, sizeof(ca));
+	ca.child_stack_base = (u64)(int)stack;
+	ca.child_stack_size = (u64)0;
+	ca.parent_tid_ptr = (u64)((int)&parent_tid);
+	ca.child_tid_ptr = (u64)((int)&child_tid);
+	ca.nr_pids = nr_pids;
+
+	if (verbose) {
+		printf("[%d, %d]: Parent:\n\t child_stack 0x%p, ptidp %llx, "
+				"ctidp %llx, pids %p\n", getpid(), gettid(),
+				stack, ca.parent_tid_ptr, ca.child_tid_ptr,
+				pids_list);
+	}
+
+	args_size = sizeof(struct clone_args);
+	rc = eclone(flags_low, &ca, args_size, pids_list);
+
+	if (verbose) {
+		printf("[%d, %d]: eclone() returned %d, error %d\n", getpid(),
+				gettid(), rc, errno);
+		fflush(stdout);
+	}
+
+	if (rc < 0 && errno == EAGAIN) {
+		printf("PASS: Unable to create a process with a pid that is "
+			"in use\n");
+		exit(0);
+	} else {
+		printf("ERROR: ");
+		return rc;
+	}
+}
+
+int main()
+{
+	int rc, pid, status;
+	unsigned long flags; 
+	int nr_pids = 1;
+
+	flags = SIGCHLD|CLONE_PARENT_SETTID|CLONE_CHILD_SETTID;
+	flags = SIGCHLD;
+
+	/*
+	 * Try to create a process with same pid as parent !
+	 */
+	pids_list[0] = pids_list[1] = getpid();
+
+	pid = myclone(do_child, (void *)CHILD_ARG, flags, nr_pids, pids_list);
+
+	if (verbose) {
+		printf("[%d, %d]: Parent waiting for %d\n", getpid(),
+					gettid(), pid);
+	}
+
+	rc = waitpid(pid, &status, __WALL);
+	if (rc < 0) {
+		printf("ERROR: ");
+		verbose = 1;
+	}
+
+	if (verbose) {
+		printf("\twaitpid(): child %d, rc %d, error %d, status 0x%x\n",
+				getpid(), rc, errno, status);
+		if (rc >=0) {
+			if (WIFEXITED(status)) {
+				printf("\t EXITED, %d\n", WEXITSTATUS(status));
+			} else if (WIFSIGNALED(status)) {
+				printf("\t SIGNALED, %d\n", WTERMSIG(status));
+			} 
+		}
+	}
+	return 0;
+}
-- 
1.6.6.1