[LTP] [PATCH] syscalls/execveat01: new test to verify execveat unlinked fd

[Eddie Horng]

2018-07-27 17:47 GMT+08:00 Cyril Hrubis <chrubis@suse.cz>:
> Hi!

Hi Cyril,
Thanks your detail review and suggestions, I have couples of
questions as below:

>> +static void do_child(void)
>> +{
>> +
>> +     char path[PATH_MAX];
>> +     char *argv[2] = {TEST_APP, NULL};
>> +     int fd;
>> +
>> +     if (tst_get_path(TEST_APP, path, sizeof(path))) {
>> +             tst_brk(TBROK | TERRNO,
>> +                      "Couldn't found "TEST_APP" binary in $PATH");
>> +     }
>> +     SAFE_CP(path, TEST_FILE_PATH);
>
> We do have a better API for this, have a look at creat07.c

Could you have more detail guide on this? ie. copy TEST_APP to
ovl mount path.

>> +     fd = SAFE_OPEN(TEST_FILE_PATH, O_PATH);
>> +     SAFE_UNLINK(TEST_FILE_PATH);
>> +
>> +     argv[0] = TEST_FILE_PATH;
>> +     TEST(execveat(fd, "", argv, NULL, AT_EMPTY_PATH));
>> +     if (TEST_ERRNO == ENOSYS) {
>> +             tst_brk(TCONF,
>> +                     "execveat is not supported in this kernel.");
>> +     }
>
> I suppose that we should handle EINVAL here, I think that we will get
> EINVAL rather than ENOSYS when kernel will not recognize __NR_execveat

EINVAL is happened to be the same return code of this testcase is expecting --
the regression introduced from 8db6c34f1dbc ("Introduce v3 namespaced
file capabilities"), therefore I might need another way to test whether kernel
recognize __NR_execveat, so that I can differentiate not recognize and the
regression. Do you have suggestion on this?

>> +int main(void)
>> +{
>> +     printf("Hello World\n");
>> +     exit(0);
>
> You can print the TPASS message from here and the result will be
> propagated to the parent program. You just need to call tst_reinit()
> that will initialize the test library. See creat07_child.c.

I change execveat_child.c as below and get errors as:
tst_test.c:144: BROK: LTP_IPC_PATH is not defined
tst_test.c:869: BROK: Test haven't reported results!

I think the cause is execveat() doesn't pass environment variables
to its child, but SAFE_EXECL in creat07.c does.
Do you suggest pass LTP_IPC_PATH in execveat() to make
tst_reinit() in execveat_child run properly, or something else?

#define TST_NO_DEFAULT_MAIN
#include "tst_test.h"

int main()
{
  tst_reinit();
  tst_res(TPASS, "execveat_child is lunched as expcted");
  return 0;
}

thanks,
Eddie