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Re: [PATCH v2] sysv: linux: Pass 64-bit version of semctl syscall
- From: Alistair Francis <alistair23 at gmail dot com>
- To: Alistair Francis <alistair dot francis at wdc dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Thu, 20 Feb 2020 09:58:48 -0800
- Subject: Re: [PATCH v2] sysv: linux: Pass 64-bit version of semctl syscall
- References: <20200205005610.31739-1-alistair.francis@wdc.com> <CAKmqyKMo-tM5=C1kUpdrHwYUbt6f1av_3L-+JWAvFCAz0YvodA@mail.gmail.com>
On Fri, Feb 14, 2020 at 8:39 AM Alistair Francis <alistair23@gmail.com> wrote:
>
> On Tue, Feb 4, 2020 at 5:02 PM Alistair Francis
> <alistair.francis@wdc.com> 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 union semun to include a struct __semid_ds32
> > which supports 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.
>
> Ping!
Ping^2
Alistair
>
> > ---
> > v2:
> > - Fix the HPPA error
> > - Simplfy the code changes
> >
> > include/sys/sem.h | 35 +++++++++++++++++++
> > sysdeps/unix/sysv/linux/bits/sem-pad.h | 1 +
> > sysdeps/unix/sysv/linux/hppa/bits/sem-pad.h | 2 ++
> > sysdeps/unix/sysv/linux/mips/bits/sem-pad.h | 2 ++
> > .../unix/sysv/linux/powerpc/bits/sem-pad.h | 2 ++
> > sysdeps/unix/sysv/linux/semctl.c | 23 +++++++++---
> > sysdeps/unix/sysv/linux/sparc/bits/sem-pad.h | 2 ++
> > sysdeps/unix/sysv/linux/x86/bits/sem-pad.h | 1 +
> > 8 files changed, 64 insertions(+), 4 deletions(-)
> >
> > diff --git a/include/sys/sem.h b/include/sys/sem.h
> > index 69fdf1f752..70b83127cb 100644
> > --- a/include/sys/sem.h
> > +++ b/include/sys/sem.h
> > @@ -5,5 +5,40 @@
> >
> > __typeof__ (semtimedop) __semtimedop attribute_hidden;
> >
> > +# endif
> > +
> > +# ifdef __SEMID_DS_HIGH
> > +# if defined (__SEMID_DS_HIGH_END)
> > +struct __semid_ds32 {
> > + struct ipc_perm sem_perm; /* permissions .. see ipc.h */
> > + __syscall_ulong_t sem_otime; /* last semop time */
> > + __syscall_ulong_t sem_ctime; /* last change time */
> > + __syscall_ulong_t sem_nsems; /* no. of semaphores in array */
> > + __syscall_ulong_t sem_otime_high;
> > + __syscall_ulong_t sem_ctime_high;
> > +};
> > +# elif defined (__SEMID_DS_HIGH_SWAP)
> > +struct __semid_ds32 {
> > + struct ipc_perm sem_perm; /* operation permission struct */
> > + __syscall_ulong_t sem_otime_high; /* last semop() time high */
> > + __syscall_ulong_t sem_otime; /* last semop() time */
> > + __syscall_ulong_t sem_ctime_high; /* last time changed by semctl() high */
> > + __syscall_ulong_t sem_ctime; /* last time changed by semctl() */
> > + __syscall_ulong_t sem_nsems; /* number of semaphores in set */
> > + __syscall_ulong_t __glibc_reserved3;
> > + __syscall_ulong_t __glibc_reserved4;
> > +};
> > +# else
> > +struct __semid_ds32 {
> > + struct ipc_perm sem_perm; /* operation permission struct */
> > + __syscall_ulong_t sem_otime; /* last semop() time */
> > + __syscall_ulong_t sem_otime_high; /* last semop() time high */
> > + __syscall_ulong_t sem_ctime; /* last time changed by semctl() */
> > + __syscall_ulong_t sem_ctime_high; /* last time changed by semctl() high */
> > + __syscall_ulong_t sem_nsems; /* number of semaphores in set */
> > + __syscall_ulong_t __glibc_reserved3;
> > + __syscall_ulong_t __glibc_reserved4;
> > +};
> > +# endif
> > # endif
> > #endif
> > diff --git a/sysdeps/unix/sysv/linux/bits/sem-pad.h b/sysdeps/unix/sysv/linux/bits/sem-pad.h
> > index 566ce039cc..18235e56df 100644
> > --- a/sysdeps/unix/sysv/linux/bits/sem-pad.h
> > +++ b/sysdeps/unix/sysv/linux/bits/sem-pad.h
> > @@ -31,3 +31,4 @@
> >
> > #define __SEM_PAD_AFTER_TIME (__TIMESIZE == 32)
> > #define __SEM_PAD_BEFORE_TIME 0
> > +#define __SEMID_DS_HIGH (__WORDSIZE == 32)
> > diff --git a/sysdeps/unix/sysv/linux/hppa/bits/sem-pad.h b/sysdeps/unix/sysv/linux/hppa/bits/sem-pad.h
> > index ee0332325b..62580792b3 100644
> > --- a/sysdeps/unix/sysv/linux/hppa/bits/sem-pad.h
> > +++ b/sysdeps/unix/sysv/linux/hppa/bits/sem-pad.h
> > @@ -24,3 +24,5 @@
> >
> > #define __SEM_PAD_AFTER_TIME 0
> > #define __SEM_PAD_BEFORE_TIME (__TIMESIZE == 32)
> > +#define __SEMID_DS_HIGH (__WORDSIZE == 32)
> > +#define __SEMID_DS_HIGH_SWAP (__WORDSIZE == 32)
> > diff --git a/sysdeps/unix/sysv/linux/mips/bits/sem-pad.h b/sysdeps/unix/sysv/linux/mips/bits/sem-pad.h
> > index 4c581f7694..12f2bd9c62 100644
> > --- a/sysdeps/unix/sysv/linux/mips/bits/sem-pad.h
> > +++ b/sysdeps/unix/sysv/linux/mips/bits/sem-pad.h
> > @@ -22,3 +22,5 @@
> >
> > #define __SEM_PAD_AFTER_TIME 0
> > #define __SEM_PAD_BEFORE_TIME 0
> > +#define __SEMID_DS_HIGH (__WORDSIZE == 32)
> > +#define __SEMID_DS_HIGH_END (__WORDSIZE == 32)
> > diff --git a/sysdeps/unix/sysv/linux/powerpc/bits/sem-pad.h b/sysdeps/unix/sysv/linux/powerpc/bits/sem-pad.h
> > index 42d8827906..a13ca5f6bd 100644
> > --- a/sysdeps/unix/sysv/linux/powerpc/bits/sem-pad.h
> > +++ b/sysdeps/unix/sysv/linux/powerpc/bits/sem-pad.h
> > @@ -24,3 +24,5 @@
> >
> > #define __SEM_PAD_AFTER_TIME 0
> > #define __SEM_PAD_BEFORE_TIME (__TIMESIZE == 32)
> > +#define __SEMID_DS_HIGH (__WORDSIZE == 32)
> > +#define __SEMID_DS_HIGH_SWAP (__WORDSIZE == 32)
> > diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
> > index 0c3eb0932f..8dcb012b0b 100644
> > --- a/sysdeps/unix/sysv/linux/semctl.c
> > +++ b/sysdeps/unix/sysv/linux/semctl.c
> > @@ -28,6 +28,9 @@ union semun
> > {
> > int val; /* value for SETVAL */
> > struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */
> > +#ifdef __SEMID_DS_HIGH
> > + struct __semid_ds32 *buf32; /* buffer for IPC_STAT & IPC_SET on 32-bit systems */
> > +#endif
> > unsigned short int *array; /* array for GETALL & SETALL */
> > struct seminfo *__buf; /* buffer for IPC_INFO */
> > };
> > @@ -43,13 +46,25 @@ 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
> > +#ifdef __SEMID_DS_HIGH
> > +/* If we aren't going to overflow the time_t sem_ctime/sem_otime set it */
> > +# if __TIMESIZE == 64 && __WORDSIZE == 32
> > + if (ret == 0)
> > + {
> > + 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
> > +#endif
> > + return ret;
> > }
> >
> > int
> > diff --git a/sysdeps/unix/sysv/linux/sparc/bits/sem-pad.h b/sysdeps/unix/sysv/linux/sparc/bits/sem-pad.h
> > index 5f4e214d12..79655b8149 100644
> > --- a/sysdeps/unix/sysv/linux/sparc/bits/sem-pad.h
> > +++ b/sysdeps/unix/sysv/linux/sparc/bits/sem-pad.h
> > @@ -24,3 +24,5 @@
> >
> > #define __SEM_PAD_AFTER_TIME 0
> > #define __SEM_PAD_BEFORE_TIME (__TIMESIZE == 32)
> > +#define __SEMID_DS_HIGH (__WORDSIZE == 32)
> > +#define __SEMID_DS_HIGH_SWAP (__WORDSIZE == 32)
> > diff --git a/sysdeps/unix/sysv/linux/x86/bits/sem-pad.h b/sysdeps/unix/sysv/linux/x86/bits/sem-pad.h
> > index 102e226997..db397857e7 100644
> > --- a/sysdeps/unix/sysv/linux/x86/bits/sem-pad.h
> > +++ b/sysdeps/unix/sysv/linux/x86/bits/sem-pad.h
> > @@ -22,3 +22,4 @@
> >
> > #define __SEM_PAD_AFTER_TIME 1
> > #define __SEM_PAD_BEFORE_TIME 0
> > +#define __SEMID_DS_HIGH 1
> > --
> > 2.25.0
> >