Re: ppc32: semctl fails

Re: ppc32: semctl fails

[Andreas Schwab]

On Dez 06 2017, Joakim Tjernlund <Joakim.Tjernlund@infinera.com> wrote:

>     st = semctl(sem, 0, IPC_STAT, &arg);

This is not a valid use of IPC_STAT.  The fourth argument must be a
object of type union semun (not a pointer), with the .buf member
pointing to the struct semid_ds object.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: ppc32: semctl fails

[Joakim Tjernlund]

On Wed, 2017-12-06 at 23:56 +0100, Andreas Schwab wrote:
>=20
> On Dez 06 2017, Joakim Tjernlund <Joakim.Tjernlund@infinera.com> wrote:
>=20
> >     st =3D semctl(sem, 0, IPC_STAT, &arg);
>=20
> This is not a valid use of IPC_STAT.  The fourth argument must be a
> object of type union semun (not a pointer), with the .buf member
> pointing to the struct semid_ds object.

Ahh, so perl had it wrong (Any perl guys here?). This is what I came up wit=
h and it works:

struct semid_ds arg;
  union semun {
    int              val;    /* Value for SETVAL */
    struct semid_ds *buf;    /* Buffer for IPC_STAT, IPC_SET */
    unsigned short  *array;  /* Array for GETALL, SETALL */
    struct seminfo  *__buf;  /* Buffer for IPC_INFO                        =
                                                               =20
                                (Linux-specific) */
  } semopts =3D {0};
  semopts.buf =3D &arg;

#if defined(IPC_PRIVATE) && defined(S_IRWXU) && defined(S_IRWXG) &&  define=
d(S_IRWXO) && defined(IPC_CREAT)
  sem =3D semget(IPC_PRIVATE, 1, S_IRWXU|S_IRWXG|S_IRWXO|IPC_CREAT);
  if (sem > -1) {
    #ifdef IPC_STAT
    st =3D semctl(sem, 0, IPC_STAT, semopts);
    if (st =3D=3D 0)
      printf("semid_ds\n");
    else
#endif /* IPC_STAT */
      printf("semctl IPC_STAT failed: errno =3D %s\n", strerror(errno));
    #ifdef IPC_RMID
    if (semctl(sem, 0, IPC_RMID, semopts) !=3D 0)
#endif /* IPC_RMID */
      printf("semctl IPC_RMID failed: errno =3D %d\n", errno);
  } else
#endif /* IPC_PRIVATE && ... */
    printf("semget failed: errno =3D %d\n", errno);
  return 0;

 Jocke=

ppc32: semctl fails

[Joakim Tjernlund]

This test, taken from perl Configure, fails on my ppc32, should it?
  semctl IPC_STAT failed: errno =3D Bad Address=20
is what I get, kernel is 4.1.43

-----------------

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/stat.h>
#ifndef S_IRUSR
#   ifdef S_IREAD
#define S_IRUSR S_IREAD
#define S_IWUSR S_IWRITE
#define S_IXUSR S_IEXEC
#   else
#define S_IRUSR 0400
#define S_IWUSR 0200
#define S_IXUSR 0100
#   endif
#   define S_IRGRP (S_IRUSR>>3)
#   define S_IWGRP (S_IWUSR>>3)
#   define S_IXGRP (S_IXUSR>>3)
#   define S_IROTH (S_IRUSR>>6)
#   define S_IWOTH (S_IWUSR>>6)
#   define S_IXOTH (S_IXUSR>>6)
#endif
#ifndef S_IRWXU
#   define S_IRWXU (S_IRUSR|S_IWUSR|S_IXUSR)
#   define S_IRWXG (S_IRGRP|S_IWGRP|S_IXGRP)
#   define S_IRWXO (S_IROTH|S_IWOTH|S_IXOTH)
#endif

#include <string.h>
#include <stdio.h>
#include <errno.h>
#ifndef errno
extern int errno;
#endif
int main() {
  int sem, st;
  struct semid_ds arg;

#if defined(IPC_PRIVATE) && defined(S_IRWXU) && defined(S_IRWXG) &&  define=
d(S_IRWXO) && defined(IPC_CREAT)
  sem =3D semget(IPC_PRIVATE, 1, S_IRWXU|S_IRWXG|S_IRWXO|IPC_CREAT);
  if (sem > -1) {
    #ifdef IPC_STAT
    st =3D semctl(sem, 0, IPC_STAT, &arg);
    if (st =3D=3D 0)
      printf("semid_ds\n");
    else
#endif /* IPC_STAT */
      printf("semctl IPC_STAT failed: errno =3D %s\n", strerror(errno));
    #ifdef IPC_RMID
    if (semctl(sem, 0, IPC_RMID, &arg) !=3D 0)
#endif /* IPC_RMID */
      printf("semctl IPC_RMID failed: errno =3D %d\n", errno);
  } else
#endif /* IPC_PRIVATE && ... */
    printf("semget failed: errno =3D %d\n", errno);

  return 0;
}=