glibc/sysdeps
Zack Weinberg 4a39c34c4f Change most internal uses of __gettimeofday to __clock_gettime.
Since gettimeofday will shortly be implemented in terms of
clock_gettime on all platforms, internal code should use clock_gettime
directly; in addition to removing a layer of indirection, this will
allow us to remove the PLT-bypass gunk for gettimeofday.  (We can't
quite do that yet, but it'll be coming later in this patch series.)
In many cases, the changed code does fewer conversions.

The changed code always assumes __clock_gettime (CLOCK_REALTIME)
cannot fail.  Most of the call sites were assuming gettimeofday could
not fail, but a few places were checking for errors.  POSIX says
clock_gettime can only fail if the clock constant is invalid or
unsupported, and CLOCK_REALTIME is the one and only clock constant
that's required to be supported.  For consistency I grepped the entire
source tree for any other places that checked for errors from
__clock_gettime (CLOCK_REALTIME), found one, and changed it too.

(For the record, POSIX also says gettimeofday can never fail.)

(It would be nice if we could declare that GNU systems will always
support CLOCK_MONOTONIC as well as CLOCK_REALTIME; there are several
places where we are using CLOCK_REALTIME where _MONOTONIC would be
more appropriate, and/or trying to use _MONOTONIC and then falling
back to _REALTIME.  But the Hurd doesn't support CLOCK_MONOTONIC yet,
and it looks like adding it would involve substantial changes to
gnumach's internals and API.  Oh well.)

A few Hurd-specific files were changed to use __host_get_time instead
of __clock_gettime, as this seemed tidier.  We also assume this cannot
fail.  Skimming the code in gnumach leads me to believe the only way
it could fail is if __mach_host_self also failed, and our
Hurd-specific code consistently assumes that can't happen, so I'm
going with that.

With the exception of support/support_test_main.c, test cases are not
modified, mainly because I didn't want to have to figure out which
test cases were testing gettimeofday specifically.

The definition of GETTIME in sysdeps/generic/memusage.h had a typo and
was not reading tv_sec at all.  I fixed this.  It appears nobody has been
generating malloc traces on a machine that doesn't have a superseding
definition.

There are a whole bunch of places where the code could be simplified
by factoring out timespec subtraction and/or comparison logic, but I
want to keep this patch as mechanical as possible.

Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
powerpc64-linux-gnu, powerpc-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
2019-10-30 17:04:10 -03:00
..
aarch64 Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
alpha Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
arm Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
csky Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
generic Change most internal uses of __gettimeofday to __clock_gettime. 2019-10-30 17:04:10 -03:00
gnu Add TCP_TX_DELAY from Linux 5.3 to netinet/tcp.h. 2019-09-27 13:37:36 +00:00
hppa Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
htl time: Introduce function to check correctness of nanoseconds value 2019-10-27 21:49:25 +01:00
hurd Prefer https to http for gnu.org and fsf.org URLs 2019-09-07 02:43:31 -07:00
i386 Prefer https to http for gnu.org and fsf.org URLs 2019-09-07 02:43:31 -07:00
ia64 Remove math-finite.h 2019-10-21 08:47:07 -03:00
ieee754 Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
init_array Prefer https to http for gnu.org and fsf.org URLs 2019-09-07 02:43:31 -07:00
m68k Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
mach Change most internal uses of __gettimeofday to __clock_gettime. 2019-10-30 17:04:10 -03:00
microblaze Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
mips Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
nios2 Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
nptl nptl: SIGCANCEL, SIGTIMER, SIGSETXID are always defined 2019-10-18 14:29:04 +02:00
posix Change most internal uses of __gettimeofday to __clock_gettime. 2019-10-30 17:04:10 -03:00
powerpc [powerpc] No need to enter "Ignore Exceptions Mode" 2019-10-02 10:30:51 -05:00
pthread Change most internal uses of __gettimeofday to __clock_gettime. 2019-10-30 17:04:10 -03:00
riscv Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
s390 S390: Add new s390 platform z15. 2019-10-18 14:57:14 +02:00
sh Split up endian.h to minimize exposure of BYTE_ORDER. 2019-10-01 14:54:46 -07:00
sparc time: Introduce function to check correctness of nanoseconds value 2019-10-27 21:49:25 +01:00
unix Change most internal uses of __gettimeofday to __clock_gettime. 2019-10-30 17:04:10 -03:00
wordsize-32 Prefer https to http for gnu.org and fsf.org URLs 2019-09-07 02:43:31 -07:00
wordsize-64 Prefer https to http for gnu.org and fsf.org URLs 2019-09-07 02:43:31 -07:00
x86 elf: Use nocancel pread64() instead of lseek()+read() 2019-10-18 15:55:33 -04:00
x86_64 Remove x64 _finite tests and references 2019-10-21 14:29:12 -03:00