[04/12] Use clock_settime to implement stime.
Commit Message
Unconditionally, on all ports, use clock_settime to implement stime,
not settimeofday or a direct syscall.
Note that the former stub implementation of stime would return -1 with
errno set to EINVAL if passed a null pointer. With this change, it
instead unconditionally dereferences the pointer, so any hypothetical
callers that passed NULL will now segfault. I don’t think this will break
any non-contrived programs.
* time/stime.c (stime): No longer a stub implementation.
Call __clock_settime.
* sysdeps/unix/stime.c: Delete file.
* sysdeps/unix/sysv/linux/syscalls.list: Remove entry for stime.
* include/time.h: Add libc_hidden_proto for __clock_settime.
* rt/clock_settime.c, sysdeps/unix/sysv/linux/clock_settime.c:
Add libc_hidden_def for __clock_settime.
---
include/time.h | 1 +
rt/clock_settime.c | 1 +
sysdeps/unix/stime.c | 39 -------------------------
sysdeps/unix/sysv/linux/clock_settime.c | 1 +
sysdeps/unix/sysv/linux/syscalls.list | 1 -
time/stime.c | 15 +++-------
6 files changed, 7 insertions(+), 51 deletions(-)
delete mode 100644 sysdeps/unix/stime.c
Comments
On 20/08/2019 10:21, Zack Weinberg wrote:
> Unconditionally, on all ports, use clock_settime to implement stime,
> not settimeofday or a direct syscall.
>
> Note that the former stub implementation of stime would return -1 with
> errno set to EINVAL if passed a null pointer. With this change, it
> instead unconditionally dereferences the pointer, so any hypothetical
> callers that passed NULL will now segfault. I don’t think this will break
> any non-contrived programs.
I agree that using a null point does not make sense, so I would also recommend
to use __nonnull ((1)) on function prototype as well.
>
> * time/stime.c (stime): No longer a stub implementation.
> Call __clock_settime.
>
> * sysdeps/unix/stime.c: Delete file.
> * sysdeps/unix/sysv/linux/syscalls.list: Remove entry for stime.
>
> * include/time.h: Add libc_hidden_proto for __clock_settime.
> * rt/clock_settime.c, sysdeps/unix/sysv/linux/clock_settime.c:
> Add libc_hidden_def for __clock_settime.
LGTM.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> include/time.h | 1 +
> rt/clock_settime.c | 1 +
> sysdeps/unix/stime.c | 39 -------------------------
> sysdeps/unix/sysv/linux/clock_settime.c | 1 +
> sysdeps/unix/sysv/linux/syscalls.list | 1 -
> time/stime.c | 15 +++-------
> 6 files changed, 7 insertions(+), 51 deletions(-)
> delete mode 100644 sysdeps/unix/stime.c
>
> diff --git a/include/time.h b/include/time.h
> index ac3163c2a5..c0421c7a28 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -22,6 +22,7 @@ extern __typeof (clock_getres) __clock_getres;
> extern __typeof (clock_gettime) __clock_gettime;
> libc_hidden_proto (__clock_gettime)
> extern __typeof (clock_settime) __clock_settime;
> +libc_hidden_proto (__clock_settime)
> extern __typeof (clock_nanosleep) __clock_nanosleep;
> extern __typeof (clock_getcpuclockid) __clock_getcpuclockid;
>
Ok.
> diff --git a/rt/clock_settime.c b/rt/clock_settime.c
> index 891925ab2c..9c4f4fbc10 100644
> --- a/rt/clock_settime.c
> +++ b/rt/clock_settime.c
> @@ -26,5 +26,6 @@ __clock_settime (clockid_t clock_id, const struct timespec *tp)
> __set_errno (ENOSYS);
> return -1;
> }
> +libc_hidden_def (__clock_settime)
> weak_alias (__clock_settime, clock_settime)
> stub_warning (clock_settime)
Ok.
> diff --git a/sysdeps/unix/stime.c b/sysdeps/unix/stime.c
> deleted file mode 100644
> index b0809be400..0000000000
> --- a/sysdeps/unix/stime.c
> +++ /dev/null
> @@ -1,39 +0,0 @@
> -/* Copyright (C) 1992-2019 Free Software Foundation, Inc.
> - This file is part of the GNU C Library.
> -
> - The GNU C Library is free software; you can redistribute it and/or
> - modify it under the terms of the GNU Lesser General Public
> - License as published by the Free Software Foundation; either
> - version 2.1 of the License, or (at your option) any later version.
> -
> - The GNU C Library is distributed in the hope that it will be useful,
> - but WITHOUT ANY WARRANTY; without even the implied warranty of
> - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> - Lesser General Public License for more details.
> -
> - You should have received a copy of the GNU Lesser General Public
> - License along with the GNU C Library; if not, see
> - <http://www.gnu.org/licenses/>. */
> -
> -#include <errno.h>
> -#include <stddef.h> /* For NULL. */
> -#include <sys/time.h>
> -#include <time.h>
> -
> -/* Set the system clock to *WHEN. */
> -
> -int
> -stime (const time_t *when)
> -{
> - struct timeval tv;
> -
> - if (when == NULL)
> - {
> - __set_errno (EINVAL);
> - return -1;
> - }
> -
> - tv.tv_sec = *when;
> - tv.tv_usec = 0;
> - return __settimeofday (&tv, (struct timezone *) 0);
> -}
Ok.
> diff --git a/sysdeps/unix/sysv/linux/clock_settime.c b/sysdeps/unix/sysv/linux/clock_settime.c
> index d837e3019c..ef1512cc91 100644
> --- a/sysdeps/unix/sysv/linux/clock_settime.c
> +++ b/sysdeps/unix/sysv/linux/clock_settime.c
> @@ -34,4 +34,5 @@ __clock_settime (clockid_t clock_id, const struct timespec *tp)
>
> return INLINE_SYSCALL_CALL (clock_settime, clock_id, tp);
> }
> +libc_hidden_def (__clock_settime)
> weak_alias (__clock_settime, clock_settime)
Ok.
> diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
> index e374f97b5f..f6cb655e2c 100644
> --- a/sysdeps/unix/sysv/linux/syscalls.list
> +++ b/sysdeps/unix/sysv/linux/syscalls.list
> @@ -62,7 +62,6 @@ setfsgid EXTRA setfsgid i:i setfsgid
> setfsuid EXTRA setfsuid i:i setfsuid
> setpgid - setpgid i:ii __setpgid setpgid
> sigaltstack - sigaltstack i:PP __sigaltstack sigaltstack
> -stime - stime i:p stime
> sysinfo EXTRA sysinfo i:p __sysinfo sysinfo
> swapon - swapon i:si __swapon swapon
> swapoff - swapoff i:s __swapoff swapoff
Ok.
> diff --git a/time/stime.c b/time/stime.c
> index de58c49562..b4d692ca32 100644
> --- a/time/stime.c
> +++ b/time/stime.c
> @@ -15,23 +15,16 @@
> License along with the GNU C Library; if not, see
> <http://www.gnu.org/licenses/>. */
>
> -#include <errno.h>
> #include <time.h>
> -#include <stddef.h>
>
> /* Set the system clock to *WHEN. */
>
> int
> stime (const time_t *when)
> {
> - if (when == NULL)
> - {
> - __set_errno (EINVAL);
> - return -1;
> - }
> + struct timespec ts;
> + ts.tv_sec = *when;
> + ts.tv_nsec = 0;
>
> - __set_errno (ENOSYS);
> - return -1;
> + return __clock_settime (CLOCK_REALTIME, &ts);
> }
> -
> -stub_warning (stime)
>
Ok.
On 8/21/19 11:10 AM, Adhemerval Zanella wrote:
>
>
> On 20/08/2019 10:21, Zack Weinberg wrote:
>> Unconditionally, on all ports, use clock_settime to implement stime,
>> not settimeofday or a direct syscall.
>>
>> Note that the former stub implementation of stime would return -1 with
>> errno set to EINVAL if passed a null pointer. With this change, it
>> instead unconditionally dereferences the pointer, so any hypothetical
>> callers that passed NULL will now segfault. I don’t think this will break
>> any non-contrived programs.
>
> I agree that using a null point does not make sense, so I would also recommend
> to use __nonnull ((1)) on function prototype as well.
Good point, but I'm not going to make this change because instead I'm
going to add a patch to the series that demotes stime to a compatibility
symbol, so its public prototype will be removed.
zw
@@ -22,6 +22,7 @@ extern __typeof (clock_getres) __clock_getres;
extern __typeof (clock_gettime) __clock_gettime;
libc_hidden_proto (__clock_gettime)
extern __typeof (clock_settime) __clock_settime;
+libc_hidden_proto (__clock_settime)
extern __typeof (clock_nanosleep) __clock_nanosleep;
extern __typeof (clock_getcpuclockid) __clock_getcpuclockid;
@@ -26,5 +26,6 @@ __clock_settime (clockid_t clock_id, const struct timespec *tp)
__set_errno (ENOSYS);
return -1;
}
+libc_hidden_def (__clock_settime)
weak_alias (__clock_settime, clock_settime)
stub_warning (clock_settime)
deleted file mode 100644
@@ -1,39 +0,0 @@
-/* Copyright (C) 1992-2019 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, see
- <http://www.gnu.org/licenses/>. */
-
-#include <errno.h>
-#include <stddef.h> /* For NULL. */
-#include <sys/time.h>
-#include <time.h>
-
-/* Set the system clock to *WHEN. */
-
-int
-stime (const time_t *when)
-{
- struct timeval tv;
-
- if (when == NULL)
- {
- __set_errno (EINVAL);
- return -1;
- }
-
- tv.tv_sec = *when;
- tv.tv_usec = 0;
- return __settimeofday (&tv, (struct timezone *) 0);
-}
@@ -34,4 +34,5 @@ __clock_settime (clockid_t clock_id, const struct timespec *tp)
return INLINE_SYSCALL_CALL (clock_settime, clock_id, tp);
}
+libc_hidden_def (__clock_settime)
weak_alias (__clock_settime, clock_settime)
@@ -62,7 +62,6 @@ setfsgid EXTRA setfsgid i:i setfsgid
setfsuid EXTRA setfsuid i:i setfsuid
setpgid - setpgid i:ii __setpgid setpgid
sigaltstack - sigaltstack i:PP __sigaltstack sigaltstack
-stime - stime i:p stime
sysinfo EXTRA sysinfo i:p __sysinfo sysinfo
swapon - swapon i:si __swapon swapon
swapoff - swapoff i:s __swapoff swapoff
@@ -15,23 +15,16 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-#include <errno.h>
#include <time.h>
-#include <stddef.h>
/* Set the system clock to *WHEN. */
int
stime (const time_t *when)
{
- if (when == NULL)
- {
- __set_errno (EINVAL);
- return -1;
- }
+ struct timespec ts;
+ ts.tv_sec = *when;
+ ts.tv_nsec = 0;
- __set_errno (ENOSYS);
- return -1;
+ return __clock_settime (CLOCK_REALTIME, &ts);
}
-
-stub_warning (stime)