Eric Blake wrote: > On Wed, Mar 09, 2022 at 11:37:14PM -0800, Khem Raj wrote: > > mcontext is not a standard layout so glibc and musl differ sadly. > > > > Fixes > > ../../m4-1.4.19/lib/sigsegv.c: In function 'sigsegv_handler': > > > > ../../m4-1.4.19/lib/sigsegv.c:223:75: > > error: 'mcontext_t' has no member named 'uc_regs'; did you mean 'gregs'? > > > > 223 | # define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) > > ucp)->uc_mcontext.uc_regs->gregs[1] > > | > > ^~~~~~~ > > Thanks for the report. As this file comes from gnulib, the fix needs > to go there first.
Thanks for the report. I'm adding this patch to GNU libsigsegv: https://git.savannah.gnu.org/gitweb/?p=libsigsegv.git;a=commitdiff;h=a6ff69873110c0a8ba6f7fd90532dbc11224828c and then this (derived) patch to Gnulib. I couldn't verify that it works, since there is no Linux distro that is based on musl libc and is ported to Linux/powerpc (32-bit). 2022-03-13 Bruno Haible <br...@clisp.org> sigsegv: Add support for Linux/PowerPC (32-bit) with musl libc. Reported by Khem Raj <raj.k...@gmail.com> in <https://lists.gnu.org/archive/html/m4-patches/2022-03/msg00000.html>. * src/sigsegv.c (SIGSEGV_FAULT_STACKPOINTER): In the Linux/PowerPC 32-bit case, handle musl libc differently. * modules/sigsegv (Files): Add m4/musl.m4. (configure.ac): Invoke gl_MUSL_LIBC. diff --git a/lib/sigsegv.c b/lib/sigsegv.c index da70ffa5fd..da64d7d0b6 100644 --- a/lib/sigsegv.c +++ b/lib/sigsegv.c @@ -227,11 +227,28 @@ int libsigsegv_version = LIBSIGSEGV_VERSION; # if defined __powerpc64__ || defined __powerpc64_elfv2__ /* 64-bit */ # define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.gp_regs[1] # else /* 32-bit */ -/* both should be equivalent */ -# if 0 -# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.regs->gpr[1] +# if MUSL_LIBC +/* musl libc has a different structure of ucontext_t in + musl/arch/powerpc/bits/signal.h. */ +/* The glibc comments say: + "Different versions of the kernel have stored the registers on signal + delivery at different offsets from the ucontext struct. Programs should + thus use the uc_mcontext.uc_regs pointer to find where the registers are + actually stored." */ +# if 0 +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.gregs[1] +# else +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_regs->gregs[1] +# endif # else -# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.uc_regs->gregs[1] +/* Assume the structure of ucontext_t in + glibc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h. */ +/* Because of the union, both definitions should be equivalent. */ +# if 0 +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.regs->gpr[1] +# else +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.uc_regs->gregs[1] +# endif # endif # endif diff --git a/modules/sigsegv b/modules/sigsegv index b723bd6814..eedce3a9d9 100644 --- a/modules/sigsegv +++ b/modules/sigsegv @@ -17,6 +17,7 @@ lib/sigsegv.c lib/stackvma.h lib/stackvma.c m4/mmap-anon.m4 +m4/musl.m4 m4/sigaltstack.m4 m4/stack-direction.m4 m4/libsigsegv.m4 @@ -46,6 +47,8 @@ if $GL_GENERATE_SIGSEGV_H; then dnl Persuade Solaris OpenIndiana <unistd.h> to declare mincore(). AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + gl_MUSL_LIBC + AC_REQUIRE([AC_CANONICAL_HOST]) case "$host_os" in solaris2.11)
