[PATCH v3 1/3] date: Use 64 prefix syscall if we have to
Alistair Francis
alistair.francis at wdc.com
Wed Sep 18 16:28:49 UTC 2019
Some 32-bit architectures no longer have the 32-bit time_t syscalls.
Instead they have suffixed syscalls that returns a 64-bit time_t. If
the architecture doesn't have the non-suffixed syscall and is using a
64-bit time_t let's use the suffixed syscall instead.
This fixes build issues when building for RISC-V 32-bit with 5.1+ kernel
headers.
If an architecture only supports the suffixed syscalls, but is still
using a 32-bit time_t fall back to the libc call.
Signed-off-by: Alistair Francis <alistair.francis at wdc.com>
---
v2:
- Fix comment typo
coreutils/date.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/coreutils/date.c b/coreutils/date.c
index feb400430..731241536 100644
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -36,7 +36,7 @@
//config:# defaults to "no": stat's nanosecond field is a bit non-portable
//config:config FEATURE_DATE_NANO
//config: bool "Support %[num]N nanosecond format specifier"
-//config: default n # syscall(__NR_clock_gettime)
+//config: default n # syscall(__NR_clock_gettime) or syscall(__NR_clock_gettime64)
//config: depends on DATE
//config: select PLATFORM_LINUX
//config: help
@@ -271,10 +271,17 @@ int date_main(int argc UNUSED_PARAM, char **argv)
*/
#endif
} else {
-#if ENABLE_FEATURE_DATE_NANO
+#if ENABLE_FEATURE_DATE_NANO && defined(__NR_clock_gettime)
/* libc has incredibly messy way of doing this,
* typically requiring -lrt. We just skip all this mess */
syscall(__NR_clock_gettime, CLOCK_REALTIME, &ts);
+#elif ENABLE_FEATURE_DATE_NANO && __TIMESIZE == 64
+ /* Let's only support the 64 suffix syscalls for 64-bit time_t.
+ * This simplifies the code for us as we don't need to convert
+ * between 64-bit and 32-bit. We also don't have a way to
+ * report overflow errors here.
+ */
+ syscall(__NR_clock_gettime64, CLOCK_REALTIME, &ts);
#else
time(&ts.tv_sec);
#endif
--
2.23.0
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