Patchwork [1/6] y2038: Introduce internal for glibc struct __timespec64

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Submitter Lukasz Majewski
Date April 14, 2019, 10:08 p.m.
Message ID <20190414220841.20243-2-lukma@denx.de>
Download mbox | patch
Permalink /patch/32283/
State New
Headers show

Comments

Lukasz Majewski - April 14, 2019, 10:08 p.m.
This type is a glibc's type similar to struct timespec
but whose tv_sec field is a __time64_t rather than a time_t,
which makes it Y2038-proof and usable to pass between user
code and Y2038-proof kernel syscalls (e.g. clock_gettime()).

To support passing this structure to the kernel - the tv_pad,
32 bit padding field has been introduced. The placement of it
depends on endiannes of the SoC.

Tested on x86_64 and ARM.

* include/time.h: Add struct __timespec64 definition
---
 include/time.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Patch

diff --git a/include/time.h b/include/time.h
index ac3163c2a5..a4a06201d5 100644
--- a/include/time.h
+++ b/include/time.h
@@ -5,6 +5,7 @@ 
 # include <bits/types/locale_t.h>
 # include <stdbool.h>
 # include <time/mktime-internal.h>
+# include <endian.h>
 
 extern __typeof (strftime_l) __strftime_l;
 libc_hidden_proto (__strftime_l)
@@ -52,6 +53,27 @@  extern void __tz_compute (__time64_t timer, struct tm *tm, int use_localtime)
   __THROW attribute_hidden;
 
 #if __TIMESIZE == 64
+# define __timespec64 timespec
+#else
+/* The glibc Y2038-proof struct __timespec64 structure for a time value.
+   To keep things Posix-ish, we keep the nanoseconds field a 32-bit
+   signed long, but since the Linux field is a 64-bit signed int, we
+   pad our tv_nsec with a 32-bit bitfield, which should always be 0. */
+
+struct __timespec64
+{
+  __time64_t tv_sec;         /* Seconds */
+# if BYTE_ORDER == BIG_ENDIAN
+  int tv_pad: 32;            /* Padding named for checking/setting */
+  __int32_t tv_nsec;         /* Nanoseconds */
+# else
+  __int32_t tv_nsec;         /* Nanoseconds */
+  int tv_pad: 32;            /* Padding named for checking/setting */
+# endif
+};
+#endif
+
+#if __TIMESIZE == 64
 # define __ctime64 ctime
 #else
 extern char *__ctime64 (const __time64_t *__timer) __THROW;