[Devel] Re: [PATCH 5/6][cr-tests]: eclone-5: nr_pids must not exceed nesting level

[Serge E. Hallyn]

Quoting Sukadev Bhattiprolu (sukadev at linux.vnet.ibm.com):
> 
> From: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
> Date: Mon, 1 Feb 2010 18:13:51 -0800
> Subject: [PATCH 5/6][cr-tests]: eclone-5: nr_pids must not exceed nesting level
> 
> Verify that eclone() fails if nr_pids exceeds the current nesting level
> of pid namespaces. Also verify that eclone() succeeds in choosing a pid
> for a process in a descendant pid namespace.
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>

Acked-by: Serge Hallyn <serue at us.ibm.com>

> ---
>  eclone/Makefile   |    2 +-
>  eclone/eclone-5.c |  174 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 175 insertions(+), 1 deletions(-)
>  create mode 100644 eclone/eclone-5.c
> 
> diff --git a/eclone/Makefile b/eclone/Makefile
> index 86ca859..5777643 100644
> --- a/eclone/Makefile
> +++ b/eclone/Makefile
> @@ -3,7 +3,7 @@ CFLAGS = -Wall
> 
>  LDFLAGS = 
> 
> -PROGS = eclone-1 eclone-2 eclone-3 eclone-4
> +PROGS = eclone-1 eclone-2 eclone-3 eclone-4 eclone-5
> 
>  all: $(PROGS)
> 
> diff --git a/eclone/eclone-5.c b/eclone/eclone-5.c
> new file mode 100644
> index 0000000..ceaef02
> --- /dev/null
> +++ b/eclone/eclone-5.c
> @@ -0,0 +1,174 @@
> +#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>
> +#define _GNU_SOURCE
> +#include <sched.h>
> +#include "clone_args.h"
> +
> +/*
> + * Verify that eclone() fails if nr_pids exceeds the current nesting level
> + * of pid namespaces
> + */
> +int verbose = 0;
> +
> +#define CHILD_TID1	377
> +#define	CHILD_TID2	399
> +#define	CHILD_ARG	(void *)0x979797
> +
> +pid_t pids_list[] = { CHILD_TID1, CHILD_TID2 };
> +int parent_tid;
> +int child_tid;
> +
> +int do_child(void *arg)
> +{
> +	if (verbose)
> +		printf("Child created with [%d, %d]\n", gettid(), getpid());
> +
> +	sleep(2);
> +	exit(0);
> +}
> +
> +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);
> +	}
> +
> +	errno = 0;
> +	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);
> +	}
> +
> +	return rc;
> +}
> +
> +int do_test(void *arg)
> +{
> +	int rc, pid, status;
> +	unsigned long flags; 
> +	int nested_ns;
> +	int nr_pids;
> +	int error;
> +
> +	nested_ns = *(int *)arg;
> +	nr_pids = 2;
> +
> +	flags = SIGCHLD|CLONE_PARENT_SETTID|CLONE_CHILD_SETTID;
> +
> +	pid = myclone(do_child, (void *)CHILD_ARG, flags, nr_pids, pids_list);
> +
> +	error = 0;
> +	if (pid < 0)
> +		error = errno;
> +
> +	/* If we did create a child, wait for it to exit */
> +	if (pid > 0) {
> +		rc = waitpid(pid, &status, __WALL);
> +		if (rc < 0) {
> +			printf("%d: ERROR: waitpid() rc %d, error %d\n", 
> +					getpid(), rc, errno);
> +			verbose = 1;
> +		}
> +	}
> +
> +	if (verbose) {
> +		printf("%d: nested_ns %d, pid %d, error %d\n", getpid(),
> +				nested_ns, pid, error);
> +	}
> +
> +	/*
> +	 * We set nr_pids to 2 above. If we cloned from current pid ns,
> +	 * eclone() must fail with EINVAL. If we eclone() from a nested pid
> +	 * ns, eclone() must succeed. In all other cases, test has failed.
> +	 */
> +	rc = 0;
> +	if (!nested_ns && (pid < 0) && (error == EINVAL)) {
> +		printf("%d: PASSED: Got EINVAL when nr_pids > nesting-depth\n",
> +				getpid());
> +	} else if (nested_ns && (pid > 0)) {
> +		printf("%d: PASSED: eclone() succeeded in nested pid-ns\n",
> +				getpid());
> +	} else {
> +		printf("%d: FAILED: nested_ns %d, pid %d, error %d\n", getpid(),
> +				nested_ns, pid, error);
> +		rc = 1;
> +	}
> +
> +	fflush(stdout);
> +	return rc;
> +}
> +
> +int main()
> +{
> +	int rc, pid, status;
> +	int nested_ns;
> +	unsigned long flags; 
> +	void *stack;
> +
> +	/* First test in current pid namespace */
> +	nested_ns = 0;
> +	rc = do_test(&nested_ns);
> +	if (rc)
> +		exit(rc);
> +
> +	/* Then test in a nested pid-namespace - use normal clone() */
> +	stack = malloc(STACKSIZE);
> +	if (!stack) {
> +		printf("ERROR: setup_stack returns NULL for size %d\n",
> +				STACKSIZE);
> +		exit(1);
> +	}
> +	stack += (STACKSIZE - 1);
> +
> +	nested_ns = 1;
> +	flags = SIGCHLD|CLONE_NEWPID|CLONE_NEWNS;
> +	pid = clone(do_test, stack, flags, (void *)&nested_ns, NULL, NULL, NULL);
> +	if (pid < 0) {
> +		printf("ERROR: clone() failed, pid %d, error %s\n", pid,
> +				strerror(errno));
> +		exit(1);
> +	}
> +
> +	rc = waitpid(pid, &status, __WALL);
> +	if (rc < 0) {
> +		printf("ERROR: waitpid() failed, rc %d, error %s\n", rc,
> +				strerror(errno));
> +		fflush(stdout);
> +		exit(1);
> +	}
> +	return 0;
> +}
> -- 
> 1.6.6.1
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