mach-spawn: fix spurious InterruptException

this was a bug in our libuv fork triggering a bug in the mach kernel

code must be careful to never use sigprocmask, setjmp, longjmp, or
similar such thread-unsafe functions to avoid this documented unspecified behavior

Author: vtjnash

deps/checksums/libuv-52d72a52cc7ccd570929990f010ed16e2ec604c8.tar.gz/md5

@@ -0,0 +1 @@
+0e6ec181c8bfd322a17dbd843b2b8ebb

deps/checksums/libuv-52d72a52cc7ccd570929990f010ed16e2ec604c8.tar.gz/sha512

@@ -0,0 +1 @@
+4bf9c8b16617691b70ea43c667ecc575d2a06b3d0c347b949d10360c012138585a13ecea5e18de81b1585a96cf7734b7cc3d6072490898f1d5531c702cf5afab

deps/checksums/libuv-8d5131b6c1595920dd30644cd1435b4f344b46c8.tar.gz/md5

@@ -1,2 +1,2 @@
 LIBUV_BRANCH=julia-uv1.9.0
-LIBUV_SHA1=8d5131b6c1595920dd30644cd1435b4f344b46c8
+LIBUV_SHA1=52d72a52cc7ccd570929990f010ed16e2ec604c8

deps/checksums/libuv-8d5131b6c1595920dd30644cd1435b4f344b46c8.tar.gz/sha512

@@ -5,7 +5,6 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <setjmp.h>
 #include <stdarg.h>
 #include <assert.h>
 #include <ctype.h>

deps/libuv.version

@@ -32,7 +32,6 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <setjmp.h>
 #include <stdint.h>
 #include <stdarg.h>
 #include <assert.h>
@@ -117,7 +116,7 @@ static void free_readstate(fl_readstate_t *rs)
   fl_exception_context_t _ctx; int l__tr, l__ca; \
   _ctx.sp=fl_ctx->SP; _ctx.frame=fl_ctx->curr_frame; _ctx.rdst=fl_ctx->readstate; _ctx.prev=fl_ctx->exc_ctx; \
   _ctx.ngchnd = fl_ctx->N_GCHND; fl_ctx->exc_ctx = &_ctx;                                    \
-  if (!setjmp(_ctx.buf)) \
+  if (!fl_setjmp(_ctx.buf)) \
     for (l__tr=1; l__tr; l__tr=0, (void)(fl_ctx->exc_ctx=fl_ctx->exc_ctx->prev))
 
 #define FL_CATCH(fl_ctx)                                                \
@@ -156,7 +155,7 @@ void fl_raise(fl_context_t *fl_ctx, value_t e)
     fl_exception_context_t *thisctx = fl_ctx->exc_ctx;
     if (fl_ctx->exc_ctx->prev)   // don't throw past toplevel
         fl_ctx->exc_ctx = fl_ctx->exc_ctx->prev;
-    longjmp(thisctx->buf, 1);
+    fl_longjmp(thisctx->buf, 1);
 }
 
 static value_t make_error_msg(fl_context_t *fl_ctx, const char *format, va_list args)

src/flisp/builtins.c

@@ -167,8 +167,25 @@ fixnum_t tofixnum(fl_context_t *fl_ctx, value_t v, const char *fname);
 char *tostring(fl_context_t *fl_ctx, value_t v, const char *fname);
 
 /* error handling */
+#if defined(_OS_WINDOWS_)
+#define fl_jmp_buf jmp_buf
+#if defined(_COMPILER_MINGW_)
+int __attribute__ ((__nothrow__,__returns_twice__)) (jl_setjmp)(jmp_buf _Buf);
+__declspec(noreturn) __attribute__ ((__nothrow__)) void (jl_longjmp)(jmp_buf _Buf, int _Value);
+#else
+int (jl_setjmp)(jmp_buf _Buf);
+void (jl_longjmp)(jmp_buf _Buf, int _Value);
+#endif
+#define fl_setjmp(a) (jl_setjmp)((a))
+#define fl_longjmp(a, b) (jl_longjmp)((a), (b))
+#else // !_OS_WINDOWS_
+#define fl_jmp_buf sigjmp_buf
+#define fl_setjmp(a) sigsetjmp((a), 0)
+#define fl_longjmp(a, b) siglongjmp((a), (b))
+#endif
+
 typedef struct _ectx_t {
-    jmp_buf buf;
+    fl_jmp_buf buf;
     uint32_t sp;
     uint32_t frame;
     uint32_t ngchnd;
@@ -179,7 +196,7 @@ typedef struct _ectx_t {
 #define FL_TRY_EXTERN(fl_ctx)                                           \
   fl_exception_context_t _ctx; int l__tr, l__ca;                        \
   fl_savestate(fl_ctx, &_ctx); fl_ctx->exc_ctx = &_ctx;                      \
-  if (!setjmp(_ctx.buf))                                                \
+  if (!fl_setjmp(_ctx.buf))                                                \
       for (l__tr=1; l__tr; l__tr=0, (void)(fl_ctx->exc_ctx=fl_ctx->exc_ctx->prev))
 
 #define FL_CATCH_EXTERN(fl_ctx)                                         \

src/flisp/flisp.c

@@ -4,7 +4,6 @@
 #include <string.h>
 #include <assert.h>
 #include <sys/types.h>
-#include <setjmp.h>
 #include "flisp.h"
 
 #ifdef __cplusplus

src/flisp/flisp.h

@@ -4,7 +4,6 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <setjmp.h>
 #include <stdarg.h>
 #include <assert.h>
 #include <ctype.h>

src/flisp/iostream.c

@@ -4,7 +4,6 @@
 #include <string.h>
 #include <assert.h>
 #include <sys/types.h>
-#include <setjmp.h>
 #include "flisp.h"
 #include "equalhash.h"
 

src/flisp/string.c

@@ -1562,11 +1562,11 @@ JL_DLLEXPORT void jl_pop_handler(int n);
 
 #if defined(_OS_WINDOWS_)
 #if defined(_COMPILER_MINGW_)
-int __attribute__ ((__nothrow__,__returns_twice__)) jl_setjmp(jmp_buf _Buf);
-__declspec(noreturn) __attribute__ ((__nothrow__)) void jl_longjmp(jmp_buf _Buf,int _Value);
+int __attribute__ ((__nothrow__,__returns_twice__)) (jl_setjmp)(jmp_buf _Buf);
+__declspec(noreturn) __attribute__ ((__nothrow__)) void (jl_longjmp)(jmp_buf _Buf, int _Value);
 #else
-int jl_setjmp(jmp_buf _Buf);
-void jl_longjmp(jmp_buf _Buf,int _Value);
+int (jl_setjmp)(jmp_buf _Buf);
+void (jl_longjmp)(jmp_buf _Buf, int _Value);
 #endif
 #define jl_setjmp_f jl_setjmp
 #define jl_setjmp_name "jl_setjmp"

src/flisp/table.c

@@ -527,10 +527,30 @@ static void *signal_listener(void *arg)
     unw_context_t *signal_context;
     int sig, critical, profile;
     int i;
+    // prevent this thread from being used to run other,
+    // potentially blocking signal handlers
+    sigfillset(&sset);
+    sigdelset(&sset, SIGSEGV);
+    sigdelset(&sset, SIGILL);
+    sigdelset(&sset, SIGKILL);
+    sigdelset(&sset, SIGBUS);
+    sigdelset(&sset, SIGABRT);
+    sigdelset(&sset, SIGSYS);
+    pthread_sigmask(SIG_SETMASK, &sset, 0);
+
     jl_sigsetset(&sset);
     while (1) {
         profile = 0;
-        sigwait(&sset, &sig);
+        sig = 0;
+        errno = 0;
+        if (sigwait(&sset, &sig)) {
+            sig = SIGABRT; // this branch can't occur, unless we had stack memory corruption of sset
+        }
+        if (!sig) {
+            // this should never happen, but it has been observed to occur on some buggy kernels (mach)
+            // when sigprocmask is incorrectly used on some other thread, instead of pthread_sigmask
+            continue;
+        }
 #ifndef HAVE_MACH
 #  ifdef HAVE_ITIMER
         profile = (sig == SIGPROF);