From 382e593bfd46e37d9f255ada8115689f40d8e362 Mon Sep 17 00:00:00 2001
From: firewave <firewave@users.noreply.github.com>
Date: Fri, 20 Oct 2023 23:18:30 +0200
Subject: [PATCH] refs #10543 - signalhandler.cpp: signal handler registration
 cleanups

- removed bogus preprocessor checks
- implement as per official documentation - https://man7.org/linux/man-pages/man2/sigaltstack.2.html
- added missing errror handling
---
 cli/signalhandler.cpp | 27 +++++++++++++--------------
 lib/config.h          |  3 +--
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/cli/signalhandler.cpp b/cli/signalhandler.cpp
index 3e98c77e075..473ef7a361e 100644
--- a/cli/signalhandler.cpp
+++ b/cli/signalhandler.cpp
@@ -34,7 +34,6 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
-//#include <features.h> // __USE_DYNAMIC_STACK_SIZE
 #include <map>
 #include <string>
 #include <sys/types.h>
@@ -54,13 +53,6 @@
 #   include <ucontext.h>
 #endif
 
-// TODO: __USE_DYNAMIC_STACK_SIZE is dependent on the features.h include and not a built-in compiler define, so it might be problematic to depend on it
-#ifdef __USE_DYNAMIC_STACK_SIZE
-static constexpr size_t MYSTACKSIZE = (16*1024)+32768; // wild guess about a reasonable buffer
-#else
-static constexpr size_t MYSTACKSIZE = 16*1024+SIGSTKSZ; // wild guess about a reasonable buffer
-#endif
-static char mytstack[MYSTACKSIZE]= {0}; // alternative stack for signal handler
 static bool bStackBelowHeap=false; // lame attempt to locate heap vs. stack address space. See CppCheckExecutor::check_wrapper()
 static FILE* signalOutput = stdout; // TODO: get rid of this
 
@@ -312,12 +304,14 @@ void register_signal_handler(FILE * const output)
 
     // set up alternative stack for signal handler
     stack_t segv_stack;
-    segv_stack.ss_sp = mytstack;
+    segv_stack.ss_sp = valloc(SIGSTKSZ);
     segv_stack.ss_flags = 0;
-    segv_stack.ss_size = MYSTACKSIZE;
-    if (sigaltstack(&segv_stack, nullptr) != 0) {
-        // TODO: log errno
-        fputs("could not set alternate signal stack context.\n", output);
+    segv_stack.ss_size = SIGSTKSZ;
+    // FIXME: https://reviews.llvm.org/D28265 indicates that this breaks backtrace() on MacOS
+    if (sigaltstack(&segv_stack, nullptr) == -1)
+    {
+        const int err = errno;
+        fprintf(output, "could not set alternate signal stack context (errno %d).", err);
         std::exit(EXIT_FAILURE);
     }
 
@@ -327,7 +321,12 @@ void register_signal_handler(FILE * const output)
     act.sa_flags=SA_SIGINFO|SA_ONSTACK;
     act.sa_sigaction=CppcheckSignalHandler;
     for (auto sig=listofsignals.cbegin(); sig!=listofsignals.cend(); ++sig) {
-        sigaction(sig->first, &act, nullptr);
+        if (sigaction(sig->first, &act, nullptr) == -1)
+        {
+            const int err = errno;
+            fprintf(stdout, "registering action for signal %d failed (errno %d)", sig->first, err);
+            std::exit(EXIT_FAILURE);
+        }
     }
 }
 
diff --git a/lib/config.h b/lib/config.h
index b9d34770be7..e7f46e7f442 100644
--- a/lib/config.h
+++ b/lib/config.h
@@ -211,8 +211,7 @@ static const std::string emptyString;
 #define USE_WINDOWS_SEH
 #endif
 
-// TODO: __GLIBC__ is dependent on the features.h include and not a built-in compiler define, so it might be problematic to depend on it
-#if !defined(NO_UNIX_BACKTRACE_SUPPORT) && defined(__GNUC__) && defined(__GLIBC__) && !defined(__CYGWIN__) && !defined(__MINGW32__) && !defined(__NetBSD__) && !defined(__SVR4) && !defined(__QNX__)
+#if !defined(NO_UNIX_BACKTRACE_SUPPORT) && defined(__GNUC__) && !defined(__CYGWIN__) && !defined(__MINGW32__) && !defined(__NetBSD__) && !defined(__SVR4) && !defined(__QNX__)
 #define USE_UNIX_BACKTRACE_SUPPORT
 #endif