[v5,1/3] y2038: Introduce internal for glibc struct __timespec64
Commit Message
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 syscalls between user code and Y2038-proof kernel.
To support passing this structure to the kernel - the tv_pad, 32 bit int,
has been introduced. The placement of it depends on endianness of the SoC.
Tested on x86_64 and ARM.
* include/time.h: Add struct __timespec64 definition
---
Changes for v5:
- Reword commit message
- Add missing preprocessor condition for x32 (to use timespec instead of
__timespec64).
Changes for v4:
- Change tv_pad's type from named bitfield to 32 bit int
Changes for v3:
- Replace __TIMESIZE with __WORDSIZE (as architectures with __TIMESIZE==64
will need to use this struct with 32 bit tv_nsec field).
- Update in-code comment
Changes for v2:
- None
---
include/time.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
@@ -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)
@@ -51,6 +52,30 @@ extern void __tzset_parse_tz (const char *tz) attribute_hidden;
extern void __tz_compute (__time64_t timer, struct tm *tm, int use_localtime)
__THROW attribute_hidden;
+#if __WORDSIZE == 64 \
+ || (defined __SYSCALL_WORDSIZE && __SYSCALL_WORDSIZE == 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 int.
+
+ As a general rule the Linux kernel is ignoring upper 32 bits of
+ tv_nsec field. */
+struct __timespec64
+{
+ __time64_t tv_sec; /* Seconds */
+# if BYTE_ORDER == BIG_ENDIAN
+ __int32_t tv_pad; /* Padding */
+ __int32_t tv_nsec; /* Nanoseconds */
+# else
+ __int32_t tv_nsec; /* Nanoseconds */
+ __int32_t tv_pad; /* Padding */
+# endif
+};
+#endif
+
#if __TIMESIZE == 64
# define __ctime64 ctime
#else