Re: [LTP] [PATCH v2 2/2] mlock/mlock02.c: add EPERM and ENOMEM errno tests

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> From: "Zeng Linggang" <zenglg.jy@cn.fujitsu.com>
> To: "Jan Stancek" <jstancek@redhat.com>
> Cc: "ltp-list" <ltp-list@lists.sourceforge.net>
> Sent: Wednesday, 19 February, 2014 10:40:03 AM
> Subject: [PATCH v2 2/2] mlock/mlock02.c: add EPERM and ENOMEM errno tests
> 
> Add EPERM and ENOMEM errno tests for mlock(2).
> 
> Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
> ---
>  testcases/kernel/syscalls/mlock/mlock02.c | 88
>  ++++++++++++++++++++++++++++---
>  1 file changed, 81 insertions(+), 7 deletions(-)

Hi,

as mentioned in part1, there are some compilation issues:
Let's pretend we are on ia64 (extra -D__ia64__ passed to gcc):
$ gcc -g -O2 -g -O2 -fno-strict-aliasing -pipe -Wall -W -D_FORTIFY_SOURCE=2 -I/usr/src/ltp/testcases/kernel/include -I../../../../include -I../../../../include   -L../../../../lib  mlock02.c   -lltp -o mlock02 -D__ia64__
mlock02.c: In function ‘setup1’:
mlock02.c:133: error: assignment of read-only location ‘*test’


> 
> diff --git a/testcases/kernel/syscalls/mlock/mlock02.c
> b/testcases/kernel/syscalls/mlock/mlock02.c
> index 1d1c853..6ccd281 100644
> --- a/testcases/kernel/syscalls/mlock/mlock02.c
> +++ b/testcases/kernel/syscalls/mlock/mlock02.c
> @@ -20,13 +20,22 @@
>   * ALGORITHM
>   * 	test 1:
>   *		Call mlock with a NULL address.  ENOMEM should be returned
> + *	test 2:
> + *		The caller was not privileged and its RLIMIT_MEMLOCK soft
> + *		resource limit was 0. EPERM should be returned
> + *	test 3:
> + *		The caller was not privileged and its RLIMIT_MEMLOCK soft
> + *		resource limit was nonzero, but tried to lock more memory than
> + *		the limit permitted. ENOMEM should be returned
>   */
>  
>  #include <errno.h>
>  #include <unistd.h>
>  #include <sys/mman.h>
> +#include <pwd.h>
>  #include "test.h"
>  #include "usctest.h"
> +#include "safe_macros.h"
>  
>  char *TCID = "mlock02";
>  
> @@ -36,25 +45,32 @@ struct test_case_t {
>  	void **addr;
>  	int len;
>  	int error;
> -	void (*setupfunc) ();
> +	int (*setupfunc) ();
> +	void (*cleanupfunc) ();

should list parameters or void

>  };
>  
>  static void *addr1;
> +static struct passwd *ltpuser;
>  static void setup(void);
>  #ifdef __ia64__
> -static void setup1(const struct test_case_t *);
> +static int setup1(const struct test_case_t *);
>  #else
> -static void setup1(void);
> +static int setup1(void);
>  #endif
> +static int setup2(void);
> +static int setup3(void);
> +static void cleanup2(void);
>  static void cleanup(void);
>  static void mlock_verify(const struct test_case_t *);
>  
>  static struct test_case_t TC[] = {
> -	{&addr1, 1024, ENOMEM, setup1},
> +	{&addr1, 1024, ENOMEM, setup1, NULL},
> +	{&addr1, 1024, EPERM, setup2, cleanup2},
> +	{&addr1+1024, 1024, ENOMEM, setup3, cleanup2},

What is at this memory location? It appears to be from heap:

(gdb) b setup3
Breakpoint 1 at 0x401b30: file mlock02.c, line 168.
(gdb) r
Starting program: /usr/src/ltp/testcases/kernel/syscalls/mlock/mlock02 
...
Breakpoint 1, setup3 () at mlock02.c:168
168	{
Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.132.el6.x86_64

(gdb) p/x &addr1
$3 = 0x608728

(gdb) p/x &addr1+1024
$4 = 0x60a728

(gdb) info proc map
process 524
cmdline = '/usr/src/ltp/testcases/kernel/syscalls/mlock/mlock02'
cwd = '/usr/src/ltp/testcases/kernel/syscalls/mlock'
exe = '/usr/src/ltp/testcases/kernel/syscalls/mlock/mlock02'
Mapped address spaces:

          Start Addr           End Addr       Size     Offset objfile
            0x400000           0x409000     0x9000          0                             /usr/src/ltp/testcases/kernel/syscalls/mlock/mlock02
            0x608000           0x609000     0x1000     0x8000                             /usr/src/ltp/testcases/kernel/syscalls/mlock/mlock02
            0x609000           0x62e000    0x25000          0                                   [heap]


>  };
>  
>  int TST_TOTAL = ARRAY_SIZE(TC);
> -static int exp_enos[] = { ENOMEM, 0 };
> +static int exp_enos[] = { ENOMEM, EPERM, 0 };
>  
>  int main(int ac, char **av)
>  {
> @@ -83,6 +99,8 @@ static void setup(void)
>  	tst_sig(NOFORK, DEF_HANDLER, cleanup);
>  
>  	TEST_PAUSE;
> +
> +	ltpuser = SAFE_GETPWNAM(cleanup, "nobody");
>  }
>  
>  static void mlock_verify(const struct test_case_t *test)
> @@ -92,6 +110,9 @@ static void mlock_verify(const struct test_case_t *test)
>  
>  	TEST(mlock(*(test->addr), test->len));
>  
> +	if (test->cleanupfunc != NULL)
> +		test->cleanupfunc();
> +
>  	if (TEST_RETURN != -1) {
>  		tst_resm(TFAIL, "mlock succeeded unexpectedly");
>  		return;
> @@ -107,17 +128,70 @@ static void mlock_verify(const struct test_case_t
> *test)
>  }
>  
>  #ifdef __ia64__
> -static void setup1(const struct test_case_t *test)
> +static int setup1(const struct test_case_t *test)
>  {
>  	test->len = getpagesize() + 1;
> +	return 0;
>  }
>  #else
> -static void setup1(void)
> +static int setup1(void)
>  {
>  	addr1 = NULL;
> +	return 0;
>  }
>  #endif
>  
> +static int setup2(void)
> +{
> +	struct rlimit rl;
> +
> +	if (geteuid() != 0) {
> +		tst_resm(TWARN, "Test needs to be run as root");
> +		return -1;
> +	}

If you add tst_require_root(NULL); to setup() that will break with TCONF and you can remove this.

> +
> +	rl.rlim_max = 0;
> +	rl.rlim_cur = 0;
> +	if (setrlimit(RLIMIT_MEMLOCK, &rl) != 0) {
> +		tst_resm(TWARN,
> +			 "setrlimit failed to set the resource for "
> +			 "RLIMIT_MEMLOCK to check for mlock()");

I'd expect TBROK here.

> +		return -1;
> +	}
> +
> +	SAFE_SETEUID(cleanup, ltpuser->pw_uid);
> +
> +	return 0;
> +}
> +
> +static int setup3(void)
> +{
> +	struct rlimit rl;
> +
> +	if (geteuid() != 0) {
> +		tst_resm(TWARN, "Test needs to be run as root");
> +		return -1;
> +	}

same as in setup2, can be removed if you add tst_require_root(NULL); to setup()

> +
> +	rl.rlim_max = 1;
> +	rl.rlim_cur = 1;
> +	if (setrlimit(RLIMIT_MEMLOCK, &rl) != 0) {
> +		tst_resm(TWARN,
> +			 "setrlimit failed to set the resource for "
> +			 "RLIMIT_MEMLOCK to check for mlock()");

I'd expect TBROK here as well.

> +		return -1;
> +	}
> +
> +	SAFE_SETEUID(cleanup, ltpuser->pw_uid);
> +
> +	return 0;
> +}

For setup2 and setup3 I'd suggest to set *addr to some reasonable value,
so that when mlock returns ENOMEM we know it wasn't because *addr was NULL.

Regards,
Jan

> +
> +static void cleanup2(void)
> +{
> +	SAFE_SETEUID(cleanup, 0);
> +}
> +
>  static void cleanup(void)
>  {
>  	TEST_CLEANUP;
> --
> 1.8.4.2
> 
> 
> 
> 

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