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- libsanitizer: __sanitizer_sigset_t for uClibc-ng matches kernel size
- libsanitizer assumes Linux sigset_t is glibc-sized (128 bytes / 1024
- bits). uClibc-ng deliberately keeps sigset_t the same size as the
- kernel sigset (8 bytes / 64 bits, except 16 bytes / 128 bits on MIPS)
- so its syscall wrappers can pass userspace sigset directly without
- translation. See libc/sysdeps/linux/common/bits/sigset.h.
- Without an override here, CHECK_TYPE_SIZE(sigset_t) and
- CHECK_STRUCT_SIZE_AND_OFFSET(sigaction, sa_mask) static asserts
- would fail. An earlier attempt bumped uClibc-ng's _SIGSET_NWORDS to
- the glibc value, which made the asserts pass at compile time but
- caused all sigaction()/sigprocmask() syscalls to return EINVAL at
- runtime, because the kernel rejects an over-sized sigsetsize argument
- ("runsvdir: Failed to ignore SIGCHLD: Invalid argument").
- Right thing: uClibc-ng's design is correct, libsanitizer just has to
- learn its actual layout. Add a SANITIZER_UCLIBC branch above the
- SANITIZER_LINUX fallback that produces the smaller sigset_t (16 bytes
- on MIPS, 8 bytes elsewhere).
- Signed-off-by: Ramin Moussavi <ramin.moussavi@yacoub.de>
- ---
- --- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
- +++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h
- @@ -570,6 +570,19 @@
- # endif
- #elif SANITIZER_APPLE
- typedef unsigned __sanitizer_sigset_t;
- +#elif SANITIZER_UCLIBC
- +// uClibc-ng deliberately keeps sigset_t the same size as the kernel's
- +// sigset_t to avoid translation in syscall wrappers (see uClibc-ng
- +// libc/sysdeps/linux/common/bits/sigset.h). Mirror that size here so
- +// CHECK_TYPE_SIZE(sigset_t) and the sigaction sa_mask offset checks
- +// agree with the actual uClibc-ng layout.
- +struct __sanitizer_sigset_t {
- +# if defined(__mips__)
- + unsigned long val[128 / (sizeof(unsigned long) * 8)];
- +# else
- + unsigned long val[64 / (sizeof(unsigned long) * 8)];
- +# endif
- +};
- #elif SANITIZER_LINUX
- struct __sanitizer_sigset_t {
- // The size is determined by looking at sizeof of real sigset_t on linux.
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