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authorZack Weinberg <zackw@panix.com>2019-08-28 08:25:49 -0400
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2019-10-30 17:05:14 -0300
commitc3f9aef063cd9d5911e20d4f2b919ff2914c7965 (patch)
treebe4e804c1cef9e7be1b37e09de8d8f5e9b7dec08
parent12cbde1dae6fa4a9a792b64564c7e0debf7544cc (diff)
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Use clock_settime to implement settimeofday.
Unconditionally, on all ports, use clock_settime to implement settimeofday. Remove sysdeps/unix/clock_settime.c, which implemented clock_settime by calling settimeofday; new OS ports must henceforth provide a real implementation of clock_settime. Hurd had a real implementation of settimeofday but not of clock_settime; this patch converts it into an implementation of clock_settime. It only supports CLOCK_REALTIME and microsecond resolution; Hurd/Mach does not appear to have any support for finer-resolution clocks. The vestigial "set time zone" feature of settimeofday complicates the generic settimeofday implementation a little. The only remaining uses of this feature that aren't just bugs, are using it to inform the Linux kernel of the offset between the hardware clock and UTC, on systems where the hardware clock doesn't run in UTC (usually because of dual-booting with Windows). There currently isn't any other way to do this. However, the callers that do this call settimeofday with _only_ the timezone argument non-NULL. Therefore, glibc's new behavior is: callers of settimeofday must supply one and only one of the two arguments. If both arguments are non-NULL, or both arguments are NULL, the call fails and sets errno to EINVAL. When only the timeval argument is supplied, settimeofday calls __clock_settime(CLOCK_REALTIME), same as stime. When only the timezone argument is supplied, settimeofday calls a new internal function called __settimezone. On Linux, only, this function will pass the timezone structure to the settimeofday system call. On all other operating systems, and on Linux architectures that don't define __NR_settimeofday, __settimezone is a stub that always sets errno to ENOSYS and returns -1. The settimeoday syscall is enabled on Linux by the flag COMPAT_32BIT_TIME, which is an option to either 32-bits ABIs or COMPAT builds (defined usually by 64-bit kernels that want to support 32-bit ABIs, such as x86). The idea to future 64-bit time_t only ABIs is to not provide settimeofday syscall. The same semantics are implemented for Linux/Alpha's GLIBC_2.0 compat symbol for settimeofday. There are no longer any internal callers of __settimeofday, so the internal prototype is removed. Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Lukasz Majewski <lukma@denx.de>
-rw-r--r--NEWS24
-rw-r--r--include/sys/time.h3
-rw-r--r--sysdeps/mach/hurd/clock_settime.c (renamed from sysdeps/unix/clock_settime.c)52
-rw-r--r--sysdeps/unix/syscalls.list1
-rw-r--r--sysdeps/unix/sysv/linux/alpha/osf_settimeofday.c14
-rw-r--r--sysdeps/unix/sysv/linux/alpha/settimeofday.c22
-rw-r--r--sysdeps/unix/sysv/linux/alpha/syscalls.list1
-rw-r--r--sysdeps/unix/sysv/linux/alpha/tv32-compat.h6
-rw-r--r--sysdeps/unix/sysv/linux/settimezone.c36
-rw-r--r--time/Makefile8
-rw-r--r--time/settimeofday.c24
-rw-r--r--time/settimezone.c (renamed from sysdeps/mach/hurd/settimeofday.c)34
12 files changed, 153 insertions, 72 deletions
diff --git a/NEWS b/NEWS
index 8727b5e..b066c75 100644
--- a/NEWS
+++ b/NEWS
@@ -34,6 +34,30 @@ Deprecated and removed features, and other changes affecting compatibility:
binaries and it has been removed from <time.h> header. This function
has been deprecated in favor of clock_settime.
+* The settimeofday function can still be used to set a system-wide time
+ zone when the operating system supports it. This is because the Linux
+ kernel reused the API, on some architectures, to describe a system-wide
+ time-zone-like offset between the software clock maintained by the kernel,
+ and the "RTC" clock that keeps time when the system is shut down.
+
+ However, to reduce the odds of this offset being set by accident,
+ settimeofday can no longer be used to set the time and the offset
+ simultaneously. If both of its two arguments are non-null, the call
+ will fail (setting errno to EINVAL).
+
+ Callers attempting to set this offset should also be prepared for the call
+ to fail and set errno to ENOSYS; this already happens on the Hurd and on
+ some Linux architectures. The Linux kernel maintainers are discussing a
+ more principled replacement for the reused API. After a replacement
+ becomes available, we will change settimeofday to fail with ENOSYS on all
+ platforms when its 'tzp' argument is not a null pointer.
+
+ Note that settimeofday itself is obsolescent according to POSIX.
+ Programs that set the system time should use clock_settime and/or
+ the adjtime family of functions instead. We may also cease to make
+ settimeofday available to newly linked binaries after there is a
+ replacement for Linux's time-zone-like offset API.
+
Changes to build and runtime requirements:
[Add changes to build and runtime requirements here]
diff --git a/include/sys/time.h b/include/sys/time.h
index 57208af..c0e30e7 100644
--- a/include/sys/time.h
+++ b/include/sys/time.h
@@ -24,8 +24,7 @@ extern int __gettimeofday (struct timeval *__tv,
struct timezone *__tz);
libc_hidden_proto (__gettimeofday)
libc_hidden_proto (gettimeofday)
-extern int __settimeofday (const struct timeval *__tv,
- const struct timezone *__tz)
+extern int __settimezone (const struct timezone *__tz)
attribute_hidden;
extern int __adjtime (const struct timeval *__delta,
struct timeval *__olddelta);
diff --git a/sysdeps/unix/clock_settime.c b/sysdeps/mach/hurd/clock_settime.c
index 54c9179..a69fdca 100644
--- a/sysdeps/unix/clock_settime.c
+++ b/sysdeps/mach/hurd/clock_settime.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1999-2019 Free Software Foundation, Inc.
+/* Copyright (C) 1991-2019 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
@@ -17,38 +17,32 @@
#include <errno.h>
#include <time.h>
-#include <sys/time.h>
+#include <hurd.h>
+#include <hurd/port.h>
#include <shlib-compat.h>
-/* Set CLOCK to value TP. */
+/* Set the current time of day.
+ This call is restricted to the super-user. */
int
-__clock_settime (clockid_t clock_id, const struct timespec *tp)
+__clock_settime (clockid_t clock_id, const struct timespec *ts)
{
- int retval = -1;
-
- /* Make sure the time cvalue is OK. */
- if (! valid_nanoseconds (tp->tv_nsec))
- {
- __set_errno (EINVAL);
- return -1;
- }
-
- switch (clock_id)
- {
- case CLOCK_REALTIME:
- {
- struct timeval tv;
- TIMESPEC_TO_TIMEVAL (&tv, tp);
- retval = __settimeofday (&tv, NULL);
- }
- break;
-
- default:
- __set_errno (EINVAL);
- break;
- }
-
- return retval;
+ error_t err;
+ mach_port_t hostpriv;
+ time_value_t tv;
+
+ if (clock_id != CLOCK_REALTIME
+ || ! valid_nanoseconds (ts->tv_nsec))
+ return __hurd_fail (EINVAL);
+
+ err = __get_privileged_ports (&hostpriv, NULL);
+ if (err)
+ return __hurd_fail (EPERM);
+
+ TIMESPEC_TO_TIME_VALUE (&tv, ts);
+ err = __host_set_time (hostpriv, tv);
+ __mach_port_deallocate (__mach_task_self (), hostpriv);
+
+ return __hurd_fail (err);
}
libc_hidden_def (__clock_settime)
diff --git a/sysdeps/unix/syscalls.list b/sysdeps/unix/syscalls.list
index 61e5360..5fedd57 100644
--- a/sysdeps/unix/syscalls.list
+++ b/sysdeps/unix/syscalls.list
@@ -76,7 +76,6 @@ setreuid - setreuid i:ii __setreuid setreuid
setrlimit - setrlimit i:ip __setrlimit setrlimit
setsid - setsid i: __setsid setsid
setsockopt - setsockopt i:iiibn setsockopt __setsockopt
-settimeofday - settimeofday i:PP __settimeofday settimeofday
setuid - setuid i:i __setuid setuid
shutdown - shutdown i:ii shutdown
sigaction - sigaction i:ipp __sigaction sigaction
diff --git a/sysdeps/unix/sysv/linux/alpha/osf_settimeofday.c b/sysdeps/unix/sysv/linux/alpha/osf_settimeofday.c
index 22de7b5..48eef67 100644
--- a/sysdeps/unix/sysv/linux/alpha/osf_settimeofday.c
+++ b/sysdeps/unix/sysv/linux/alpha/osf_settimeofday.c
@@ -32,8 +32,18 @@ attribute_compat_text_section
__settimeofday_tv32 (const struct timeval32 *tv32,
const struct timezone *tz)
{
- struct timeval tv = valid_timeval_to_timeval64 (*tv32);
- return __settimeofday (&tv, tz);
+ if (__glibc_unlikely (tz != 0))
+ {
+ if (tv32 != 0)
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+ return __settimezone (tz);
+ }
+
+ struct timespec ts = valid_timeval32_to_timespec (*tv32);
+ return __clock_settime (CLOCK_REALTIME, &ts);
}
compat_symbol (libc, __settimeofday_tv32, settimeofday, GLIBC_2_0);
diff --git a/sysdeps/unix/sysv/linux/alpha/settimeofday.c b/sysdeps/unix/sysv/linux/alpha/settimeofday.c
new file mode 100644
index 0000000..36a6901
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/alpha/settimeofday.c
@@ -0,0 +1,22 @@
+/* settimeofday -- Set the current time of day. Linux/Alpha/tv64 version.
+ Copyright (C) 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/>. */
+
+/* We can use the generic implementation, but we have to override its
+ default symbol version. */
+#define VERSION_settimeofday GLIBC_2.1
+#include <time/settimeofday.c>
diff --git a/sysdeps/unix/sysv/linux/alpha/syscalls.list b/sysdeps/unix/sysv/linux/alpha/syscalls.list
index c786aa7..95a27e1 100644
--- a/sysdeps/unix/sysv/linux/alpha/syscalls.list
+++ b/sysdeps/unix/sysv/linux/alpha/syscalls.list
@@ -24,7 +24,6 @@ pciconfig_iobase EXTRA pciconfig_iobase 3 __pciconfig_iobase pciconfig_iobase
# timeval64 entry points (see osf_*.c for GLIBC_2.0 timeval32 equivalents)
gettimeofday - gettimeofday i:pP __GI___gettimeofday gettimeofday@@GLIBC_2.1 __gettimeofday@@GLIBC_2.1
-settimeofday - settimeofday i:PP __settimeofday settimeofday@@GLIBC_2.1
getitimer - getitimer i:ip __getitimer getitimer@@GLIBC_2.1
setitimer - setitimer i:ipP __setitimer setitimer@@GLIBC_2.1
utimes - utimes i:sp __utimes utimes@@GLIBC_2.1
diff --git a/sysdeps/unix/sysv/linux/alpha/tv32-compat.h b/sysdeps/unix/sysv/linux/alpha/tv32-compat.h
index d0b4cdc..5f86e66 100644
--- a/sysdeps/unix/sysv/linux/alpha/tv32-compat.h
+++ b/sysdeps/unix/sysv/linux/alpha/tv32-compat.h
@@ -83,6 +83,12 @@ valid_timeval64_to_timeval (const struct timeval tv64)
return (struct timeval32) { tv64.tv_sec, tv64.tv_usec };
}
+static inline struct timespec
+valid_timeval32_to_timespec (const struct timeval32 tv)
+{
+ return (struct timespec) { tv.tv_sec, tv.tv_usec * 1000 };
+}
+
static inline void
rusage64_to_rusage32 (struct rusage32 *restrict r32,
const struct rusage *restrict r64)
diff --git a/sysdeps/unix/sysv/linux/settimezone.c b/sysdeps/unix/sysv/linux/settimezone.c
new file mode 100644
index 0000000..4aa86b3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/settimezone.c
@@ -0,0 +1,36 @@
+/* Obsolete set system time. Linux version.
+ Copyright (C) 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 <sys/time.h>
+#include <sysdep.h>
+
+/* Set the system-wide timezone.
+ This call is restricted to the super-user.
+ This operation is considered obsolete, kernel support may not be
+ available on all architectures. */
+int
+__settimezone (const struct timezone *tz)
+{
+#ifdef __NR_settimeofday
+ return INLINE_SYSCALL_CALL (settimeofday, NULL, tz);
+#else
+ __set_errno (ENOSYS);
+ return -1;
+#endif
+}
diff --git a/time/Makefile b/time/Makefile
index ad8844e..6de4e41 100644
--- a/time/Makefile
+++ b/time/Makefile
@@ -31,13 +31,13 @@ headers := time.h sys/time.h sys/timeb.h bits/time.h \
routines := offtime asctime clock ctime ctime_r difftime \
gmtime localtime mktime time \
- gettimeofday settimeofday adjtime tzset \
- tzfile getitimer setitimer \
+ gettimeofday settimeofday settimezone \
+ adjtime tzset tzfile getitimer setitimer \
stime dysize timegm ftime \
getdate strptime strptime_l \
strftime wcsftime strftime_l wcsftime_l \
- timespec_get \
- clock_getcpuclockid clock_getres \
+ timespec_get \
+ clock_getcpuclockid clock_getres \
clock_gettime clock_settime clock_nanosleep
aux := era alt_digit lc-time-cleanup
diff --git a/time/settimeofday.c b/time/settimeofday.c
index 6aa4832..ad57ad4 100644
--- a/time/settimeofday.c
+++ b/time/settimeofday.c
@@ -16,6 +16,7 @@
<https://www.gnu.org/licenses/>. */
#include <errno.h>
+#include <time.h>
#include <sys/time.h>
/* Set the current time of day and timezone information.
@@ -23,9 +24,24 @@
int
__settimeofday (const struct timeval *tv, const struct timezone *tz)
{
- __set_errno (ENOSYS);
- return -1;
+ if (__glibc_unlikely (tz != 0))
+ {
+ if (tv != 0)
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+ return __settimezone (tz);
+ }
+
+ struct timespec ts;
+ TIMEVAL_TO_TIMESPEC (tv, &ts);
+ return __clock_settime (CLOCK_REALTIME, &ts);
}
-stub_warning (settimeofday)
-weak_alias (__settimeofday, settimeofday)
+#ifdef VERSION_settimeofday
+weak_alias (__settimeofday, __settimeofday_w);
+default_symbol_version (__settimeofday_w, settimeofday, VERSION_settimeofday);
+#else
+weak_alias (__settimeofday, settimeofday);
+#endif
diff --git a/sysdeps/mach/hurd/settimeofday.c b/time/settimezone.c
index 31bffca..b9969c9 100644
--- a/sysdeps/mach/hurd/settimeofday.c
+++ b/time/settimezone.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991-2019 Free Software Foundation, Inc.
+/* Copyright (C) 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
@@ -17,36 +17,12 @@
#include <errno.h>
#include <sys/time.h>
-#include <hurd.h>
-#include <hurd/port.h>
-/* Set the current time of day and timezone information.
+/* Set the system-wide timezone.
This call is restricted to the super-user. */
int
-__settimeofday (const struct timeval *tv, const struct timezone *tz)
+__settimezone (const struct timezone *tz)
{
- error_t err;
- mach_port_t hostpriv;
-
- if (tz != NULL)
- {
- errno = ENOSYS;
- return -1;
- }
-
- err = __get_privileged_ports (&hostpriv, NULL);
- if (err)
- return __hurd_fail (EPERM);
-
- /* `time_value_t' and `struct timeval' are in fact identical with the
- names changed. */
- err = __host_set_time (hostpriv, *(time_value_t *) tv);
- __mach_port_deallocate (__mach_task_self (), hostpriv);
-
- if (err)
- return __hurd_fail (err);
-
- return 0;
+ __set_errno (ENOSYS);
+ return -1;
}
-
-weak_alias (__settimeofday, settimeofday)