Re: [PATCH v2] Use LFS and 64 bit time for installed programs (BZ #15333)

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 12/01/2022 11:13, Stefan Liebler wrote:
> On 14/12/2021 20:35, DJ Delorie via Libc-alpha wrote:
> ...
>>
>> LGTM
>> Reviewed-by: DJ Delorie <dj@redhat.com>
>>
> 
> Starting with this commit a6d2f948b71adcb5ea395cb04833bc645eab45e6, I
> get a test fail on s390:
> FAIL: resolv/tst-p_secstodate
> 
> Test 0: 0 -> 19700101000000
> Test 1: 12345 -> 19700101000000
> test 1 failedTest 2: 999999999 -> 19700101000000
> test 2 failedTest 3: 2147483647 -> 19700101000000
> test 3 failedTest 4: 2147483648 -> <overflow>
> Test 5: 4294967295 -> <overflow>
> 
> It turns out that there is a type-mismatch of time_t on caller and
> callee side.
> 
> in libresolv.so: resolv/res_debug.c: __p_secstodate(u_long secs)
> time_t clock = secs;
> struct tm *time = __gmtime_r(&clock, &timebuf);
> 
> (gdb) p &clock
> $1 = (time_t *) 0x7ffff1c8
> (gdb) ptype time_t
> type = long long
> (gdb) p	sizeof(time_t)
> $2 = 8
> (gdb) x/2xw 0x7ffff1c8
> 0x7ffff1c8:     0x00000000	0x7fffffff
> 
> The secs are stored as 8byte long long on stack and the pointer is
> passed to __gmtime_r in libc.so:
> time/gmtime.c:
> /* Provide a 32-bit variant if needed.  */
> #if __TIMESIZE != 64
> struct tm *
> __gmtime_r (const time_t *t, struct tm *tp)
> {
>   __time64_t t64 = *t;
>   return __gmtime64_r (&t64, tp);
> }
> #endif
> 
> (gdb) ptype time_t
> type = long
> (gdb) p	sizeof(time_t)
> $3 = 4
> (gdb) p         *t
> $4 = 0
> (gdb) ptype __time64_t
> type = long long
> 
> On libc.so side, time_t is defined as 4byte long, thus the value of t is
> read as 0x0 instead of 0x7fffffff.
> 
> resolv/res_debug.c is built with -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64
> and time/gmtime.c is built without those defines.
> 
> 
> @Adhemerval:
> Can you please have a look?


libresolv should not be built with the time64 flags, the above patch should fix
it.

diff --git a/Makeconfig b/Makeconfig
index 06f1cca320..9b6fc6b08f 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -867,7 +867,7 @@ endif
 +extra-math-flags = $(if $(filter libm,$(in-module)),-fno-math-errno,-fmath-errno)
 
 # Use 64 bit time_t support for installed programs
-installed-modules = nonlib nscd lddlibc4 libresolv ldconfig locale_programs \
+installed-modules = nonlib nscd lddlibc4 ldconfig locale_programs \
                    iconvprogs libnss_files libnss_compat libnss_db libnss_hesiod \
                    libutil libpcprofile libSegFault
 +extra-time-flags = $(if $(filter $(installed-modules),\

I have this issue on my backlog since I saw it on powerpc32.  I will check on
i686 and powerpc and install it.