Print a stack trace on unexpected term signal (e.g. SIGABRT)

For OSX and Linux, add a signal handler to SIGABRT, SGIFPE, SIGILL,
SIGSEGV, and SIGBUS. When the program terminates unexpectedly the
handler will print the current stack to the terminal to help determine
the location of the failure.

On OSX the output will look like:

```
Stack trace:
4   zstd                                0x000000010927ed96 main + 16886
5   libdyld.dylib                       0x00007fff767d1015 start + 1
6   ???                                 0x0000000000000001 0x0 + 1
```

On Linux the output will look like:

```
Stack trace:
./zstd() [0x4b8e1b]
./zstd() [0x4b928a]
./zstd() [0x403dc2]
/lib64/libc.so.6(__libc_start_main+0xf5) [0x7f5e0fbb0445]
./zstd() [0x405754]
```

As is, the code does not function on WIN32.

See also: https://oroboro.com/stack-trace-on-crash/

lib/common/zstd_common.c

@@ -15,10 +15,21 @@
 ***************************************/
 #include <stdlib.h>      /* malloc, calloc, free */
 #include <string.h>      /* memset */
+#include <stdio.h>       /* fprintf(), stderr */
+#include <signal.h>      /* signal() */
+#ifndef _WIN32
+#include <execinfo.h>    /* backtrace, backtrace_symbols, symbollist */
+#endif
 #include "error_private.h"
 #include "zstd_internal.h"
 
 
+/*-************************************
+*  Display Macros
+**************************************/
+#define DISPLAY(...)         fprintf(stderr, __VA_ARGS__)
+
+
 /*-****************************************
 *  Version
 ******************************************/
@@ -79,3 +90,46 @@ void ZSTD_free(void* ptr, ZSTD_customMem customMem)
             free(ptr);
     }
 }
+
+
+/*-*********************************************************
+*  Termination signal trapping (Print debug stack trace)
+***********************************************************/
+#define MAX_STACK_FRAMES    50
+
+#ifndef _WIN32
+static void ABRThandler(int sig)
+{
+   void* addrlist[MAX_STACK_FRAMES + 1];
+   char** symbollist;
+   U32 addrlen, i;
+
+   (void)sig;
+
+   DISPLAY("Stack trace:\n");
+   // Retrieve current stack addresses.
+   addrlen = backtrace(addrlist, sizeof(addrlist) / sizeof(void*));
+   if (addrlen == 0) {
+      DISPLAY("\n");
+      return;
+   }
+   // Create readable strings to each frame.
+   symbollist = backtrace_symbols(addrlist, addrlen);
+   // Print the stack trace, excluding calls handling the signal.
+   for (i = 4; i < addrlen; i++) {
+      DISPLAY("%s\n", symbollist[i]);
+   }
+   free(symbollist);
+}
+#endif
+
+void ZSTD_addAbortHandler()
+{
+#ifndef _WIN32
+    signal(SIGABRT, ABRThandler);
+    signal(SIGFPE, ABRThandler);
+    signal(SIGILL, ABRThandler);
+    signal(SIGSEGV, ABRThandler);
+    signal(SIGBUS, ABRThandler);
+#endif
+}

lib/common/zstd_internal.h

@@ -206,6 +206,9 @@ void* ZSTD_malloc(size_t size, ZSTD_customMem customMem);
 void* ZSTD_calloc(size_t size, ZSTD_customMem customMem);
 void ZSTD_free(void* ptr, ZSTD_customMem customMem);
 
+/* custom crash signal handler */
+void ZSTD_addAbortHandler(void);
+
 
 MEM_STATIC U32 ZSTD_highbit32(U32 val)   /* compress, dictBuilder, decodeCorpus */
 {

programs/fileio.c

@@ -157,7 +157,7 @@ static void clearHandler(void)
 }
 
 
-/* ************************************************************
+/*-************************************************************
 * Avoid fseek()'s 2GiB barrier with MSVC, macOS, *BSD, MinGW
 ***************************************************************/
 #if defined(_MSC_VER) && _MSC_VER >= 1400

programs/zstdcli.c

@@ -39,6 +39,7 @@
 #endif
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_maxCLevel */
 #include "zstd.h"     /* ZSTD_VERSION_STRING */
+#include "zstd_internal.h" /* ZSTD_addAbortHandler */
 
 
 /*-************************************
@@ -511,6 +512,9 @@ int main(int argCount, const char* argv[])
     if (exeNameMatch(programName, ZSTD_UNLZ4)) { operation=zom_decompress; FIO_setCompressionType(FIO_lz4Compression); }                                   /* behave like unlz4, also supports multiple formats */
     memset(&compressionParams, 0, sizeof(compressionParams));
 
+    /* init crash handler */
+    ZSTD_addAbortHandler();
+
     /* command switches */
     for (argNb=1; argNb<argCount; argNb++) {
         const char* argument = argv[argNb];