[glibc] y2038: Convert gai_suspend to support 64 bit time

[glibc] y2038: Convert gai_suspend to support 64 bit time

[Lukasz Majewski]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=47f78f36836f480b2b7a2041480be966b3a698e3

commit 47f78f36836f480b2b7a2041480be966b3a698e3
Author: Lukasz Majewski <lukma@denx.de>
Date:   Mon Nov 30 14:33:12 2020 +0100

    y2038: Convert gai_suspend to support 64 bit time
    
    This change uses (in gai_misc.h):
    - __futex_abstimed_wait64 (instead of futex_reltimed_wait)
    - __futex_abstimed_wait_cancellable64
            (instead of futex_reltimed_wait_cancellable)
            from ./sysdeps/nptl/futex-helpers.h
    
    The gai_suspend() accepts relative timeout, which then is converted to
    absolute one.
    
    The i686-gnu port (HURD) do not define DONT_NEED_GAI_MISC_COND and as it
    doesn't (yet) support 64 bit time it uses not converted
    pthread_cond_timedwait().
    
    The __gai_suspend() is supposed to be run on ports with __TIMESIZE !=64 and
    __WORDSIZE==32. It internally utilizes __gai_suspend_time64() and hence the
    conversion from 32 bit struct timespec to 64 bit one is required.
    
    For ports supporting 64 bit time the __gai_suspend_time64() will be used
    either via alias (to __gai_suspend when __TIMESIZE==64) or redirection
    (when -D_TIME_BITS=64 is passed).
    
    Build tests:
    ./src/scripts/build-many-glibcs.py glibcs
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
    Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Diff:
---
 include/netdb.h         |  7 ++++++
 resolv/gai_suspend.c    | 61 +++++++++++++++++++++++++++++--------------------
 sysdeps/nptl/gai_misc.h | 11 +++++----
 3 files changed, 50 insertions(+), 29 deletions(-)

diff --git a/include/netdb.h b/include/netdb.h
index 49d63c1338..645b85dc62 100644
--- a/include/netdb.h
+++ b/include/netdb.h
@@ -194,6 +194,13 @@ extern int ruserpass (const char *host, const char **aname,
 		      const char **apass);
 libc_hidden_proto (ruserpass)
 
+# if __TIMESIZE == 64
+#  define __gai_suspend_time64 __gai_suspend
+# else
+extern int __gai_suspend_time64 (const struct gaicb *const list[], int ent,
+                                 const struct __timespec64 *timeout);
+libanl_hidden_proto (__gai_suspend_time64)
+# endif
 
 /* The following definition has been removed from the public header
    since we don't want people to use them.  */
diff --git a/resolv/gai_suspend.c b/resolv/gai_suspend.c
index 734f9b4500..d75abeb7e3 100644
--- a/resolv/gai_suspend.c
+++ b/resolv/gai_suspend.c
@@ -24,10 +24,9 @@
 
 #include <gai_misc.h>
 
-
 int
-gai_suspend (const struct gaicb *const list[], int ent,
-	     const struct timespec *timeout)
+__gai_suspend_time64 (const struct gaicb *const list[], int ent,
+                      const struct __timespec64 *timeout)
 {
   struct waitlist waitlist[ent];
   struct requestlist *requestlist[ent];
@@ -63,6 +62,19 @@ gai_suspend (const struct gaicb *const list[], int ent,
 	  }
       }
 
+  struct __timespec64 ts;
+  if (timeout != NULL)
+    {
+      __clock_gettime64 (CLOCK_MONOTONIC, &ts);
+      ts.tv_sec += timeout->tv_sec;
+      ts.tv_nsec += timeout->tv_nsec;
+      if (ts.tv_nsec >= 1000000000)
+	{
+	  ts.tv_nsec -= 1000000000;
+	  ts.tv_sec++;
+	}
+    }
+
   if (none)
     {
       if (cnt < ent)
@@ -83,29 +95,11 @@ gai_suspend (const struct gaicb *const list[], int ent,
 
 #ifdef DONT_NEED_GAI_MISC_COND
       result = 0;
-      GAI_MISC_WAIT (result, cntr, timeout, 1);
+      GAI_MISC_WAIT (result, cntr, timeout == NULL ? NULL : &ts, 1);
 #else
-      if (timeout == NULL)
-	result = pthread_cond_wait (&cond, &__gai_requests_mutex);
-      else
-	{
-	  /* We have to convert the relative timeout value into an
-	     absolute time value with pthread_cond_timedwait expects.  */
-	  struct timespec now;
-	  struct timespec abstime;
-
-          __clock_gettime (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)
-	    {
-	      abstime.tv_nsec -= 1000000000;
-	      abstime.tv_sec += 1;
-	    }
-
-	  result = pthread_cond_timedwait (&cond, &__gai_requests_mutex,
-					   &abstime);
-	}
+      struct timespec ts32 = valid_timespec64_to_timespec (ts);
+      result = pthread_cond_timedwait (&cond, &__gai_requests_mutex,
+                                       timeout == NULL ? NULL : &ts32);
 #endif
 
       /* Now remove the entry in the waiting list for all requests
@@ -155,3 +149,20 @@ gai_suspend (const struct gaicb *const list[], int ent,
 
   return result;
 }
+
+#if __TIMESIZE != 64
+libanl_hidden_def (__gai_suspend_time64)
+
+int
+__gai_suspend (const struct gaicb *const list[], int ent,
+	       const struct timespec *timeout)
+{
+  struct __timespec64 ts64;
+
+  if (timeout != NULL)
+    ts64 = valid_timespec_to_timespec64 (*timeout);
+
+  return __gai_suspend_time64 (list, ent, timeout != NULL ? &ts64 : NULL);
+}
+#endif
+weak_alias (__gai_suspend, gai_suspend)
diff --git a/sysdeps/nptl/gai_misc.h b/sysdeps/nptl/gai_misc.h
index c1d5e2e6f0..c72a863974 100644
--- a/sysdeps/nptl/gai_misc.h
+++ b/sysdeps/nptl/gai_misc.h
@@ -46,11 +46,12 @@
 	do								      \
 	  {								      \
 	    if (cancel)							      \
-	      status = futex_reltimed_wait_cancelable (			      \
-		(unsigned int *) futexaddr, oldval, timeout, FUTEX_PRIVATE);  \
+	      status = __futex_abstimed_wait_cancelable64 (		      \
+		(unsigned int *) futexaddr, oldval, CLOCK_MONOTONIC, timeout, \
+		FUTEX_PRIVATE);						      \
 	    else							      \
-	      status = futex_reltimed_wait ((unsigned int *) futexaddr,	      \
-		oldval, timeout, FUTEX_PRIVATE);	      		      \
+	      status = __futex_abstimed_wait64 ((unsigned int *) futexaddr,   \
+		oldval, CLOCK_REALTIME, timeout, FUTEX_PRIVATE);	      \
 	    if (status != EAGAIN)					      \
 	      break;							      \
 									      \
@@ -62,6 +63,8 @@
 	  result = EINTR;						      \
 	else if (status == ETIMEDOUT)					      \
 	  result = EAGAIN;						      \
+	else if (status == EOVERFLOW)					      \
+	  result = EOVERFLOW;						      \
 	else								      \
 	  assert (status == 0 || status == EAGAIN);			      \
 									      \