From 46da4c4e090e0412cee0777f1e8b219964781da7 Mon Sep 17 00:00:00 2001
From: Eneas U de Queiroz <cotequeiroz@gmail.com>
Date: Fri, 8 Oct 2021 14:39:52 -0300
Subject: [PATCH] Avoid problems with 64-bit time_t
The clock_gettime() calls are being handled by calling
syscall(__NR_clock_gettime, ...), which is not portable between systems
using 32-bit and 64-bit time_t. This is being done to avoid having to
link agains librt.
So, use the standard function, and add a test to see if we can compile
a test without the library, including it otherwise.
Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
---
Makefile.flags | 6 ++++++
coreutils/date.c | 6 ++----
libbb/time.c | 2 +-
3 files changed, 9 insertions(+), 5 deletions(-)
--- a/Makefile.flags
+++ b/Makefile.flags
@@ -124,6 +124,12 @@ CFLAGS += --sysroot=$(CONFIG_SYSROOT)
export SYSROOT=$(CONFIG_SYSROOT)
endif
+# glibc versions before 2.17 need to link with -rt to use clock_gettime
+RT_NEEDED := $(shell echo 'int main(void){struct timespec tp; return clock_gettime(CLOCK_MONOTONIC, &tp);}' >rttest.c; $(CC) $(CFLAGS) -include time.h -o /dev/null rttest.c >/dev/null 2>&1 || echo "y"; rm rttest.c)
+ifeq ($(RT_NEEDED),y)
+LDLIBS += rt
+endif
+
# Android has no separate crypt library
# gcc-4.2.1 fails if we try to feed C source on stdin:
# echo 'int main(void){return 0;}' | $(CC) $(CFLAGS) -lcrypt -o /dev/null -xc -
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -37,7 +37,7 @@
//config:config FEATURE_DATE_NANO
//config: bool "Support %[num]N nanosecond format specifier"
//config: default n
-//config: depends on DATE # syscall(__NR_clock_gettime)
+//config: depends on DATE # clock_gettime()
//config: select PLATFORM_LINUX
//config: help
//config: Support %[num]N format specifier. Adds ~250 bytes of code.
@@ -265,9 +265,7 @@ int date_main(int argc UNUSED_PARAM, cha
#endif
} else {
#if ENABLE_FEATURE_DATE_NANO
- /* libc has incredibly messy way of doing this,
- * typically requiring -lrt. We just skip all this mess */
- syscall(__NR_clock_gettime, CLOCK_REALTIME, &ts);
+ clock_gettime(CLOCK_REALTIME, &ts);
#else
time(&ts.tv_sec);
#endif
--- a/libbb/time.c
+++ b/libbb/time.c
@@ -243,7 +243,7 @@ char* FAST_FUNC strftime_YYYYMMDDHHMMSS(
* typically requiring -lrt. We just skip all this mess */
static void get_mono(struct timespec *ts)
{
- if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, ts))
+ if (clock_gettime(CLOCK_MONOTONIC, ts))
bb_error_msg_and_die("clock_gettime(MONOTONIC) failed");
}
unsigned long long FAST_FUNC monotonic_ns(void)