On Thu, 21 Mar 2024 at 14:13:38 +0500, Andrey Rakhmatullin wrote: > On Wed, Mar 20, 2024 at 03:05:34AM +0000, Thorsten Glaser wrote: > > cc -Ilibumockdev-preload.so.0.0.0.p -I. -I.. -fdiagnostics-color=always > > -Wall -Winvalid-pch -std=gnu11 -Werror=missing-prototypes > > -Werror=strict-prototypes -Werror=nested-externs -Werror=pointer-arith > > -Werror=implicit-function-declaration -Werror=implicit-int > > -Werror=int-conversion -Werror=old-style-definition -Werror=pointer-arith > > -Werror=init-self -Werror=format-security -Werror=format=2 > > -Werror=return-type -Werror=uninitialized -Wcast-align -Wno-error=pragmas > > -Wno-error=discarded-qualifiers -Wno-error=incompatible-pointer-types > > -Wno-error=pointer-sign -Wno-unused-but-set-variable -Wno-unused-function > > -Wno-unused-label -Wno-unused-value -Wno-unused-variable -g -O2 > > -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. > > -specs=/usr/share/dpkg/pie-compile.specs -fstack-protector-strong -Wformat > > -Werror=format-security -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 > > -D_TIME_BITS=64 -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -fvisibility=default > > -MD -MQ libumockdev-preload.so.0.0.0.p/src_libumockdev-preload.c.o -MF > > libumockdev-preload.so.0.0.0.p/src_libumockdev-preload.c.o.d -o > > libumockdev-preload.so.0.0.0.p/src_libumockdev-preload.c.o -c > > ../src/libumockdev-preload.c > > In file included from /usr/include/features.h:393, > > from /usr/include/assert.h:35, > > from ../src/libumockdev-preload.c:31: > > /usr/include/features-time64.h:26:5: error: #error "_TIME_BITS=64 is > > allowed only with _FILE_OFFSET_BITS=64" > > 26 | # error "_TIME_BITS=64 is allowed only with _FILE_OFFSET_BITS=64" > > | ^~~~~ > > > > > > I admit I don’t exactly see what’s going on here. Does it > > maybe #unset _FILE_OFFSET_BITS or something? > It does. src/libumockdev-preload.c: > > /* override -D_FILE_OFFSET_BITS, it breaks us */ > #undef _FILE_OFFSET_BITS > > This has the same roots as > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1065973 as this file > says "The initial code for intercepting function calls was inspired and > partially copied from kmod's testsuite". Maybe it can also have the same > fix (but that bug isn't fixed yet, though it has a proposed fix).
This appears to be because umockdev is based on a LD_PRELOAD module that interposes wrapped or mock versions of glibc functions like stat() that are sensitive to the sizes of off_t and time_t. I don't think the proposed fix in kmod is correct, and I don't think an equivalent in umockdev would be correct either. Since glibc 2.34, on 32-bit architectures all such LD_PRELOAD modules will need updating to also wrap __lstat64_time64(), __stat64_time64(), __fstat64_time64() and __fstatat64_time64() on architectures where they exist - otherwise, programs and libraries compiled with 64-bit time_t will bypass the wrapped stat(), stat64() etc. and call __stat64_time64() instead, and therefore the wrapping will be ineffective and umockdev's mock devices will not be seen. fakeroot, fakechroot and other LD_PRELOAD modules that interpose stat() will already be doing something similar, and might provide a useful reference for what is needed. Here's the equivalent in fakechroot: https://github.com/dex4er/fakechroot/pull/104/commits/dac74cd68cfb6eeaae9cd13bdc48737a44980df9 smcv
