[PATCH 2/2] y2038: Convert aio_suspend to support 64 bit time

Lukasz Majewski lukma@denx.de
Thu Oct 29 14:46:14 GMT 2020


The aio_suspend function has been converted to support 64 bit time. It was
also necessary to provide Linux specific copy of aio_suspend.c to avoid
problems on i686-gnu (i.e. HURD) port, which is not providing
pthread_cond_timedwait() supporting 64 bit time.

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
---
 include/aio.h                         |  8 +++
 sysdeps/nptl/aio_misc.h               |  4 +-
 sysdeps/nptl/futex-internal.h         | 87 +++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/aio_suspend.c | 41 ++++++++++---
 4 files changed, 130 insertions(+), 10 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..5c553cce56 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 cd356e4fa8..1535509e71 100644
--- a/sysdeps/nptl/futex-internal.h
+++ b/sysdeps/nptl/futex-internal.h
@@ -608,4 +608,91 @@ __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:
+      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:
+      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/unix/sysv/linux/aio_suspend.c b/sysdeps/unix/sysv/linux/aio_suspend.c
index ad03f13558..8ce7bfedb0 100644
--- a/sysdeps/unix/sysv/linux/aio_suspend.c
+++ b/sysdeps/unix/sysv/linux/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))
     {
@@ -183,10 +183,10 @@ 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.  */
-	  struct timespec now;
-	  struct timespec abstime;
+	  struct __timespec64 now;
+	  struct __timespec64 abstime;
 
-	  __clock_gettime (CLOCK_REALTIME, &now);
+	  __clock_gettime64 (CLOCK_REALTIME, &now);
 	  abstime.tv_nsec = timeout->tv_nsec + now.tv_nsec;
 	  abstime.tv_sec = timeout->tv_sec + now.tv_sec;
 	  if (abstime.tv_nsec >= 1000000000)
@@ -195,8 +195,8 @@ aio_suspend (const struct aiocb *const list[], int nent,
 	      abstime.tv_sec += 1;
 	    }
 
-	  result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
-					   &abstime);
+	  result = __pthread_cond_timedwait64 (&cond, &__aio_requests_mutex,
+					       &abstime);
 	}
 #endif
 
@@ -250,4 +250,29 @@ 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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