musl defines stat64 as stat, leading to this build error:
gcc -o libfaketime.o -c -std=gnu99 -Wall -Wextra -Werror -DFAKE_PTHREAD -DFAKE_STAT -DFAKE_UTIME -DFAKE_SLEEP -DFAKE_TIMERS -DFAKE_INTERNAL_CALLS -fPIC -DPREFIX='"'/nix/store/qpyvvrcas950da98mssw6ixlw7ckvyrb-libfaketime-0.9.11'"' -DLIBDIRNAME='"'/lib'"' -Wno-nonnull-compare libfaketime.c
In file included from libfaketime.c:55:
libfaketime.c:1276:5: error: redefinition of ‘stat’
1276 | int stat64 (const char *path, struct stat64 *buf)
| ^~~~~~
/nix/store/g9cgi4yyn5vrd1f9axj8gxdvwzv5ssvk-musl-1.2.5-dev/include/sys/stat.h:80:5: note: previous definition of ‘stat’ with type ‘int(const char *, struct stat *)’
80 | int stat(const char *__restrict, struct stat *__restrict);
| ^~~~
make[1]: *** [Makefile:161: libfaketime.o] Error 1
Fix it by only defining stat64 when building against glibc, since it's
not straight forward to detect musl, and it's the safest approach; there
might be other libc implementations that behave like musl.
Fixes: 53ba71e547 ("Handle stat64() call")
Add ft_sem_*() functions that use the POSIX semaphore API.
In preparation for adding System V semaphores as an alternative to POSIX
semaphores, because glibc breaks POSIX semaphores when operating in
mixed 32- and 64-bit environments[1].
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=17980
To give more context, stat64 is a child of large-file support (LFS)
back in 1996, during the transition from 32-bit to 64-bit. People
wanted 64-bit inodes in 32-bit systems, hence stat and stat64.
Nowadays where everything is 64-bit, stat64 is mostly just an alias
to stat, as stat is already native 64-bit. On modern implementations
like musl, stat64 is even dropped entirely as a sane default. We
observe the same in darwin's stat.h:
#if !__DARWIN_ONLY_64_BIT_INO_T
struct stat64 __DARWIN_STRUCT_STAT64;
#endif /* !__DARWIN_ONLY_64_BIT_INO_T */
Because struct stat64 doesn't ever exist on aarch64-darwin, and we
don't have to worry about people using stat64 calls, we can safely
remove all stat64 bloat, according to __DARWIN_ONLY_64_BIT_INO_T.
I nuked fake_stat64buf because only STAT64_HANDLER is using it, and
only non-darwin stat64 things use that handler. I didn't do more
because people might still use stat64 things on x86_64 (on glibc)
and other older 32-bit platforms, and we still need to hook those.
A loose follow up to PR #453. Fixes the remaining clang warnings on
aarch64-darwin.
This fixes the recursive pthread_once deadlock on darwin platforms.
It looks something like this:
Trace/BPT trap: 5
BUG IN CLIENT OF LIBPLATFORM: Trying to recursively lock an os_once_t
The macro __APPLEOSX__ is never defined, instead __APPLE__ should be used.
This mistake inadvertently caused system_time_from_system() to always take
the linux code path on darwin, leading to recursive calls during ftpl_init().
This was exposed by PR #488 which removed the ad-hoc recursion detection
that previously masked this issue.
This reverts commit 8ef74e33b6
"Swapped out pthread_rwlock_xxlock() ..."
This could result in concurrent uses of pthread_cond_* erroneously
returning EAGAIN, which is not permitted by the spec and which the
application way well treat as a bug. This seems to be happening in
gem2deb in ci.debian.net.
The commit message in 8ef74e33b6 says (rewrapped)
Swapped out pthread_rwlock_xxlock(), which doesn't return if it
can't obtain the lock, with pthread_rwlock_xxtrylock() followed by
sched yield and error code return. The issue is sometimes a thread
calling pthread_cond_init() or pthread_cond_destroy() can't
acquire the lock when another thread is waiting on a condition
variable notification via pthread_cond_timedwait(), and thus the
thread calling pthread_cond_init() or pthread_cond_destroy() end
up hanging indefinitely.
I don't think this is true. The things that are done with
monotonic_conds_lock held are HASH_ADD_PTR HASH_FIND_PTR etc. on
monotonic_conds, which should all be fast and AFAICT don't in turn
take any locks. So it shouldn't deadlock.
I conjecture that the underlying bug being experienced by the author
of "Swapped out pthread_rwlock_xxlock" was the lack of ftpl_init - ie,
access to an uninitialised pthread_rwlock_t. That might result in a
hang.
Otherwise we can use this in an uninitialised state, which is not
allowed.
We call ftpl_init in pthread_cond_init_232, but the application might
not have called that. For example, it might have a static condition
variable set up with PTHREAD_COND_INITIALIZER.
timespec.tv_nsec is 32-bit, even though timeval.tv_usec is
64-bit (weirdly). This doesn't matter very much in practice because
* on little endian architectures (which is all our 32-bit release
arches) writing to a too big integer ends up writing the
desired value in the desired location, and
* it doesn't affect the overall struct size on any of our actual
architectures (which align the uint64_t to 8 so must make the
whole struct 16 not 12), so the write overflow is harmless.
> #include <time.h>
> #include <sys/time.h>
> #include <stdio.h>
> struct timeval tv;
> struct timespec ts;
> int main(void) {
> printf("time_t %lld\n", (unsigned long long) sizeof(time_t));
> printf("timeval %lld %lld %lld\n",
> (unsigned long long) sizeof(tv),
> (unsigned long long) sizeof(tv.tv_sec),
> (unsigned long long) sizeof(tv.tv_usec)
> );
> printf("timespec %lld %lld %lld\n",
> (unsigned long long) sizeof(ts),
> (unsigned long long) sizeof(ts.tv_sec),
> (unsigned long long) sizeof(ts.tv_nsec)
> );
> }
> (sid_armhf-dchroot)iwj@amdahl:~/Faketime/test$ gcc t.c
> (sid_armhf-dchroot)iwj@amdahl:~/Faketime/test$ ./a.out
> time_t 8
> timeval 16 8 8
> timespec 16 8 4
> (sid_armhf-dchroot)iwj@amdahl:~/Faketime/test$
Since debian generally added 64-bit time support on 32-bit
arches, now glibc sometimes calls the clock_gettime64 syscall
(and library wrapper). This function was missing, and is added here.
Patch originally supplied here
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1064555
We should ignore the return value for logging function, to fix a new gcc ftbfs
libmallocintercept.c: In function ‘print_msg’:
libmallocintercept.c:27:9: error: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Werror=unused-result]
27 | write(0, msg, strlen(msg));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
