On 3/10/20 5:29 PM, Vineet Gupta via Libc-alpha wrote:
> Hi Alistair,
>
> On 3/4/20 5:26 PM, Alistair Francis wrote:
>> The semctl_syscall() function passes a union semun to the kernel. The
>> union includes struct semid_ds as a member. On 32-bit architectures the
>> Linux kernel provides a *_high version of the 32-bit sem_otime and
>> sem_ctime values. These can be combined to get a 64-bit version of the
>> time.
>>
>> This patch adjusts the struct semid_ds to support the *_high versions
>> of sem_otime and sem_ctime. For 32-bit systems with a 64-bit time_t
>> this can be used to get a 64-bit time from the two 32-bit values.
>>
>> We protect this new code via the __IPC_TIME64 marco, which is only true
>> for 32-bit architectures with a 64-bit time_t.
[snip...]
>>
>> diff --git a/bits/ipc.h b/bits/ipc.h
>> index e2981fd5c3..9ac8485193 100644
>> --- a/bits/ipc.h
>> +++ b/bits/ipc.h
>> @@ -29,7 +29,11 @@
>> /* Control commands for `msgctl', `semctl', and `shmctl'. */
>> #define IPC_RMID 0 /* remove identifier */
>> #define IPC_SET 1 /* set `ipc_perm' options */
>> -#define IPC_STAT 2 /* get `ipc_perm' options */
>> +#if __TIMESIZE == 64 && __WORDSIZE == 32
>> +# define IPC_STAT 0x102 /* Get `ipc_perm' options. */
>> +#else
>> +# define IPC_STAT 2 /* Get `ipc_perm' options. */
>> +#endif
>
> Why is this needed. Linux kernel seems to be returning EINVAL for this cmd-id and
> following fail for ARC.
>
> FAIL: sysvipc/test-sysvmsg
> FAIL: sysvipc/test-sysvsem
> FAIL: sysvipc/test-sysvshm
>
> Shouldn't this use the default __IPC_64 value which is 0 not 0x100.
>
>> diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
>> index 0c3eb0932f..3ac6d01b84 100644
>> --- a/sysdeps/unix/sysv/linux/semctl.c
>> +++ b/sysdeps/unix/sysv/linux/semctl.c
>> @@ -23,11 +23,16 @@
>> #include <shlib-compat.h>
>> #include <errno.h>
>>
>> +#define __IPC_TIME64 (IPC_STAT & __IPC_64)
So __IPC_TIME64 can only happen if we have 0x102 based cmd ? But doesn't
asm-generic ABI preclude the 0x100 ?
>> +
>> /* Define a `union semun' suitable for Linux here. */
>> union semun
>> {
>> int val; /* value for SETVAL */
>> struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */
>> +#if __WORDSIZE == 32
>> + struct __semid_ds32 *buf32; /* 32-bit buffer for IPC_STAT & IPC_SET */
>> +#endif
>> unsigned short int *array; /* array for GETALL & SETALL */
>> struct seminfo *__buf; /* buffer for IPC_INFO */
>> };
>> @@ -43,13 +48,25 @@ union semun
>> static int
>> semctl_syscall (int semid, int semnum, int cmd, union semun arg)
>> {
>> + int ret;
>> #ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
>> - return INLINE_SYSCALL_CALL (semctl, semid, semnum, cmd | __IPC_64,
>> - arg.array);
>> + ret = INLINE_SYSCALL_CALL (semctl, semid, semnum, cmd | __IPC_64,
>> + arg.array);
>> #else
>> - return INLINE_SYSCALL_CALL (ipc, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
>> - SEMCTL_ARG_ADDRESS (arg));
>> + ret = INLINE_SYSCALL_CALL (ipc, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
>> + SEMCTL_ARG_ADDRESS (arg));
>> +#endif
>> +
>> +#if __IPC_TIME64
>> + if (ret == 0 && (cmd & __IPC_TIME64))
>> + {
>> + arg.buf->sem_ctime = arg.buf32->sem_ctime |
>> + ((time_t) arg.buf32->sem_ctime_high << 32);
>> + arg.buf->sem_otime = arg.buf32->sem_otime |
>> + ((time_t) arg.buf32->sem_otime_high << 32);
>> + }
>> #endif
>> + return ret;
>> }
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