[PATCH v3] y2038: Convert aio_suspend to support 64 bit time
Lukasz Majewski
lukma@denx.de
Wed Nov 18 07:58:53 GMT 2020
The aio_suspend function has been converted to support 64 bit time.
In the __aio_suspend_common64() function not all occurrences of struct
timespec, clock_gettime() and pthread_cond_timedwait() have been replaced
with their 64 bit counterparts, as i686-gnu port (HURD) don't #define
DONT_NEED_AIO_MISC_COND and requires them (as it is not yet supporting 64
bit time for being Y2038 safe).
This change uses:
- New __futex_reltimed_wait64 (instead of futex_reltimed_wait)
- New __futex_reltimed_wait_cancellable64
(instead of futex_reltimed_wait_cancellable)
from ./sysdeps/nptl/futex-helpers.h
The aio_suspend() accepts relative timeout.
The __aio_suspend() is supposed to be run on ports with __TIMESIZE !=64 and
__WORDSIZE==32. It internally utilizes __aio_suspend_time64() and hence the
conversion from 32 bit struct timespec to 64 bit one is required.
For ports supporting 64 bit time the __aio_suspend_time64() will be used
either via alias (to __aio_suspend when __TIMESIZE==64) or redirection
(when -D_TIME_BITS=64 is passed).
Build tests:
./src/scripts/build-many-glibcs.py glibcs
---
Changes for v2:
- Add missing -EOVERFLOW error handling for __futex_reltimed_wait64 and
_futex_reltimed_wait_cancelable64
Changes for v3:
- Remove "__" prefix from futex_reltimed_wait64 and
futex_reltimed_wait_cancellable64
- Remove some code, as HURD is not defining DONT_NEED_AIO_MISC_COND
(i.e. Linux ports are defining it) and add in-code explanation why
the code is NOT converted to support 64 bit time.
- Rewrite the commit message
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
include/aio.h | 8 +++
sysdeps/nptl/aio_misc.h | 4 +-
sysdeps/nptl/futex-internal.h | 93 +++++++++++++++++++++++++++++++++++
sysdeps/pthread/aio_suspend.c | 39 +++++++++++++--
4 files changed, 139 insertions(+), 5 deletions(-)
diff --git a/include/aio.h b/include/aio.h
index 90c74f9951..c7f4233310 100644
--- a/include/aio.h
+++ b/include/aio.h
@@ -9,6 +9,14 @@ extern void __aio_init (const struct aioinit *__init);
lio_listio and we do not issue events for each individual list
element. */
#define LIO_NO_INDIVIDUAL_EVENT 128
+
+# if __TIMESIZE == 64
+# define __aio_suspend_time64 __aio_suspend
+# else
+extern int __aio_suspend_time64 (const struct aiocb *const list[], int nent,
+ const struct __timespec64 *timeout);
+librt_hidden_proto (__aio_suspend_time64)
+# endif
#endif
#endif
diff --git a/sysdeps/nptl/aio_misc.h b/sysdeps/nptl/aio_misc.h
index 3f195f4794..b9d226c98d 100644
--- a/sysdeps/nptl/aio_misc.h
+++ b/sysdeps/nptl/aio_misc.h
@@ -45,10 +45,10 @@
do \
{ \
if (cancel) \
- status = futex_reltimed_wait_cancelable ( \
+ status = futex_reltimed_wait_cancelable64 ( \
(unsigned int *) futexaddr, oldval, timeout, FUTEX_PRIVATE); \
else \
- status = futex_reltimed_wait ((unsigned int *) futexaddr, \
+ status = futex_reltimed_wait64 ((unsigned int *) futexaddr, \
oldval, timeout, FUTEX_PRIVATE); \
if (status != EAGAIN) \
break; \
diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
index c27d0cdac8..e351e28d1d 100644
--- a/sysdeps/nptl/futex-internal.h
+++ b/sysdeps/nptl/futex-internal.h
@@ -609,4 +609,97 @@ __futex_clock_wait_bitset64 (int *futexp, int val, clockid_t clockid,
const struct __timespec64 *abstime,
int private) attribute_hidden;
+static __always_inline int
+futex_reltimed_wait64 (unsigned int *futex_word, unsigned int expected,
+ const struct __timespec64 *reltime, int private)
+{
+ int err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
+ __lll_private_flag (FUTEX_WAIT, private),
+ expected, reltime);
+#ifndef __ASSUME_TIME64_SYSCALLS
+ if (err == -ENOSYS)
+ {
+ if (in_time_t_range (reltime->tv_sec))
+ {
+ struct timespec ts32 = valid_timespec64_to_timespec (*reltime);
+
+ err = INTERNAL_SYSCALL_CALL (futex, futex_word,
+ __lll_private_flag (FUTEX_WAIT,
+ private),
+ expected, &ts32);
+ }
+ else
+ err = -EOVERFLOW;
+ }
+#endif
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ case -EOVERFLOW: /* Passed relative timeout uses 64 bit time_t type, but
+ underlying kernel does not support 64 bit time_t futex
+ syscalls. */
+ return -err;
+
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ futex_fatal_error ();
+ }
+}
+
+/* Like futex_reltimed_wait but is a POSIX cancellation point. */
+static __always_inline int
+futex_reltimed_wait_cancelable64 (unsigned int *futex_word,
+ unsigned int expected,
+ const struct __timespec64 *reltime,
+ int private)
+{
+ int err = INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word,
+ __lll_private_flag (FUTEX_WAIT, private),
+ expected, reltime);
+#ifndef __ASSUME_TIME64_SYSCALLS
+ if (err == -ENOSYS)
+ {
+ if (in_time_t_range (reltime->tv_sec))
+ {
+ struct timespec ts32 = valid_timespec64_to_timespec (*reltime);
+
+ err = INTERNAL_SYSCALL_CANCEL (futex, futex_word,
+ __lll_private_flag (FUTEX_WAIT,
+ private),
+ expected, &ts32);
+ }
+ else
+ err = -EOVERFLOW;
+ }
+#endif
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ case -EOVERFLOW: /* Passed relative timeout uses 64 bit time_t type, but
+ underlying kernel does not support 64 bit time_t futex
+ syscalls. */
+ return -err;
+
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ futex_fatal_error ();
+ }
+}
+
#endif /* futex-internal.h */
diff --git a/sysdeps/pthread/aio_suspend.c b/sysdeps/pthread/aio_suspend.c
index ad03f13558..eebe10536e 100644
--- a/sysdeps/pthread/aio_suspend.c
+++ b/sysdeps/pthread/aio_suspend.c
@@ -94,7 +94,7 @@ cleanup (void *arg)
#ifdef DONT_NEED_AIO_MISC_COND
static int
__attribute__ ((noinline))
-do_aio_misc_wait (unsigned int *cntr, const struct timespec *timeout)
+do_aio_misc_wait (unsigned int *cntr, const struct __timespec64 *timeout)
{
int result = 0;
@@ -105,8 +105,8 @@ do_aio_misc_wait (unsigned int *cntr, const struct timespec *timeout)
#endif
int
-aio_suspend (const struct aiocb *const list[], int nent,
- const struct timespec *timeout)
+__aio_suspend_common64 (const struct aiocb *const list[], int nent,
+ const struct __timespec64 *timeout)
{
if (__glibc_unlikely (nent < 0))
{
@@ -183,6 +183,14 @@ aio_suspend (const struct aiocb *const list[], int nent,
{
/* We have to convert the relative timeout value into an
absolute time value with pthread_cond_timedwait expects. */
+ /* Y2038: The below code is used by ports which do NOT
+ #define DONT_NEED_AIO_MISC_COND flag (e.g. i686-gnu)
+ Ports which define it use futex syscalls supporting 64 bit
+ time. As a result below code don't need to be adjusted to
+ support 64 bit time as it is advised to either add support
+ for DONT_NEED_AIO_MISC_COND flag or provide
+ __pthread_cond_timedwait64() implementation and use struct
+ __timespec64 and __clock_gettime64(). */
struct timespec now;
struct timespec abstime;
@@ -250,4 +258,29 @@ aio_suspend (const struct aiocb *const list[], int nent,
return result;
}
+int
+__aio_suspend_time64 (const struct aiocb *const list[], int nent,
+ const struct __timespec64 *timeout)
+{
+ return __aio_suspend_common64 (list, nent, timeout);
+}
+
+#if __TIMESIZE != 64
+librt_hidden_def (__aio_suspend_time64)
+
+int
+__aio_suspend(const struct aiocb *const list[], int nent,
+ const struct timespec *timeout)
+{
+ struct __timespec64 ts64;
+
+ if (timeout != NULL)
+ {
+ ts64 = valid_timespec_to_timespec64 (*timeout);
+ }
+
+ return __aio_suspend_time64 (list, nent, timeout != NULL ? &ts64 : NULL);
+}
+#endif
+weak_alias (__aio_suspend, aio_suspend)
weak_alias (aio_suspend, aio_suspend64)
--
2.20.1
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