[safestack] Various Solaris fixes (#99290)

Even with the `-u __safestack_init` link order fixed on Solaris, there
are still several safestack test issues left:

- While 540fd42 enabled safestack on
Solaris in the driver unconditionally, it ignored that Solaris also
exists on SPARC and forgot to enable SPARC support for the runtime lib.
This patch fixes that.

- The tests fail to link with undefined references to
`__sanitizer_internal_memset` etc in `safestack.cpp.o` and
`interception_linux.cpp.o`. These are from indirectly including
`sanitizer_redefine_builtins.h`. Instead of using the implementations
from `sanitizer_common` as was done in [[safestack] Various Solaris
fixes](#98469), this patch
disables the interception as discussed in [Revert "[safestack] Various
Solaris fixes"](#98541). A
similar issue affects 32-bit Linux/sparc where compiling `safestack.cpp`
with `-ftrivial-auto-var-init=pattern` causes the compiler to generate
calls to `memset` to initialize a `pthread_attr_t` which is larger than
can be handled inline. This is avoided by defining
`SANITIZER_COMMON_NO_REDEFINE_BUILTINS` in `safestack.cpp` and also
adding definitions of the interceptors that just forward to `libc` for
the benefit of `interception_linux.cpp`.

- The `pthread*.c` tests `FAIL` with

``` safestack CHECK failed:
/vol/llvm/src/llvm-project/local/compiler-rt/lib/safestack/safestack.cpp:227
size ```

The problem is that `pthread_attr_init` initializes the `stacksize`
attribute to 0, signifying the default. Unless explicitly overridded, it
stays that way. I think this is allowed by XPG7. Since safestack cannot
deal with this, I set `size` to the defaults documented in
`pthread_create(3C)`. Unfortunately, there's no macro for those values
outside of private `libc` headers.

- The Solaris `syscall` interface isn't stable. This is not just a
theoretical concern, but the syscalls have changed incompatibly several
times in the past. Therefore this patch switches the implementations of
`TgKill` (where `SYS_lwp_kill` doesn't exist on Solaris 11.4 anyway),
`Mmap`, `Munmap`, and `Mprotect` to the same `_REAL*` solution already
used in `sanitizer_solaris.cpp`.

With those changes, safestack compiles and all tests `PASS`, so the
tests are re-enabled for good.

Tested on `amd64-pc-solaris2.11`, `sparcv9-sun-solaris2.11`,
`x86_64-pc-linux-gnu`, and `sparc64-unknown-linux-gnu`.

compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake

@@ -77,7 +77,7 @@ set(ALL_UBSAN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64} ${RISCV64}
     ${MIPS32} ${MIPS64} ${PPC64} ${S390X} ${SPARC} ${SPARCV9} ${HEXAGON}
     ${LOONGARCH64})
 set(ALL_SAFESTACK_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM64} ${MIPS32} ${MIPS64}
-    ${HEXAGON} ${LOONGARCH64})
+    ${HEXAGON} ${LOONGARCH64} ${SPARC} ${SPARCV9})
 set(ALL_CFI_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64} ${MIPS64}
     ${HEXAGON} ${LOONGARCH64})
 set(ALL_SCUDO_STANDALONE_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64}

compiler-rt/lib/safestack/safestack.cpp

@@ -13,14 +13,39 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define SANITIZER_COMMON_NO_REDEFINE_BUILTINS
+
 #include "safestack_platform.h"
 #include "safestack_util.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
 
 #include <errno.h>
+#include <string.h>
 #include <sys/resource.h>
 
 #include "interception/interception.h"
 
+// interception.h drags in sanitizer_redefine_builtins.h, which in turn
+// creates references to __sanitizer_internal_memcpy etc.  The interceptors
+// aren't needed here, so just forward to libc.
+extern "C" {
+SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memcpy(void *dest,
+                                                                const void *src,
+                                                                size_t n) {
+  return memcpy(dest, src, n);
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memmove(
+    void *dest, const void *src, size_t n) {
+  return memmove(dest, src, n);
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memset(void *s, int c,
+                                                                size_t n) {
+  return memset(s, c, n);
+}
+}  // extern "C"
+
 using namespace safestack;
 
 // TODO: To make accessing the unsafe stack pointer faster, we plan to
@@ -224,6 +249,17 @@ INTERCEPTOR(int, pthread_create, pthread_t *thread,
     pthread_attr_destroy(&tmpattr);
   }
 
+#if SANITIZER_SOLARIS
+  // Solaris pthread_attr_init initializes stacksize to 0 (the default), so
+  // hardcode the actual values as documented in pthread_create(3C).
+  if (size == 0)
+#  if defined(_LP64)
+    size = 2 * 1024 * 1024;
+#  else
+    size = 1024 * 1024;
+#  endif
+#endif
+
   SFS_CHECK(size);
   size = RoundUpTo(size, kStackAlign);
 

compiler-rt/lib/safestack/safestack_platform.h

@@ -17,6 +17,7 @@
 #include "sanitizer_common/sanitizer_platform.h"
 
 #include <dlfcn.h>
+#include <errno.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -68,6 +69,24 @@ static void *GetRealLibcAddress(const char *symbol) {
   SFS_CHECK(real_##func);
 #endif
 
+#if SANITIZER_SOLARIS
+#  define _REAL(func) _##func
+#  define DEFINE__REAL(ret_type, func, ...) \
+    extern "C" ret_type _REAL(func)(__VA_ARGS__)
+
+#  if !defined(_LP64) && _FILE_OFFSET_BITS == 64
+#    define _REAL64(func) _##func##64
+#  else
+#    define _REAL64(func) _REAL(func)
+#  endif
+#  define DEFINE__REAL64(ret_type, func, ...) \
+    extern "C" ret_type _REAL64(func)(__VA_ARGS__)
+
+DEFINE__REAL64(void *, mmap, void *a, size_t b, int c, int d, int e, off_t f);
+DEFINE__REAL(int, munmap, void *a, size_t b);
+DEFINE__REAL(int, mprotect, void *a, size_t b, int c);
+#endif
+
 using ThreadId = uint64_t;
 
 inline ThreadId GetTid() {
@@ -91,11 +110,10 @@ inline int TgKill(pid_t pid, ThreadId tid, int sig) {
   (void)pid;
   return _REAL(_lwp_kill, tid, sig);
 #elif SANITIZER_SOLARIS
-#  ifdef SYS_lwp_kill
-  return syscall(SYS_lwp_kill, tid, sig);
-#  else
-  return -1;
-#  endif
+  (void)pid;
+  errno = thr_kill(tid, sig);
+  // TgKill is expected to return -1 on error, not an errno.
+  return errno != 0 ? -1 : 0;
 #elif SANITIZER_FREEBSD
   return syscall(SYS_thr_kill2, pid, tid, sig);
 #else
@@ -110,8 +128,7 @@ inline void *Mmap(void *addr, size_t length, int prot, int flags, int fd,
 #elif SANITIZER_FREEBSD && (defined(__aarch64__) || defined(__x86_64__))
   return (void *)__syscall(SYS_mmap, addr, length, prot, flags, fd, offset);
 #elif SANITIZER_SOLARIS
-  return (void *)(uintptr_t)syscall(SYS_mmap, addr, length, prot, flags, fd,
-                                    offset);
+  return _REAL64(mmap)(addr, length, prot, flags, fd, offset);
 #else
   return (void *)syscall(SYS_mmap, addr, length, prot, flags, fd, offset);
 #endif
@@ -121,6 +138,8 @@ inline int Munmap(void *addr, size_t length) {
 #if SANITIZER_NETBSD
   DEFINE__REAL(int, munmap, void *a, size_t b);
   return _REAL(munmap, addr, length);
+#elif SANITIZER_SOLARIS
+  return _REAL(munmap)(addr, length);
 #else
   return syscall(SYS_munmap, addr, length);
 #endif
@@ -130,6 +149,8 @@ inline int Mprotect(void *addr, size_t length, int prot) {
 #if SANITIZER_NETBSD
   DEFINE__REAL(int, mprotect, void *a, size_t b, int c);
   return _REAL(mprotect, addr, length, prot);
+#elif SANITIZER_SOLARIS
+  return _REAL(mprotect)(addr, length, prot);
 #else
   return syscall(SYS_mprotect, addr, length, prot);
 #endif

compiler-rt/test/safestack/lit.cfg.py

@@ -33,5 +33,5 @@
         )
     )
 
-if config.host_os not in ["Linux", "FreeBSD", "NetBSD"]:
+if config.host_os not in ["Linux", "FreeBSD", "NetBSD", "SunOS"]:
     config.unsupported = True