Merge pull request #501 from BenCat07/master

Breakpad

src/hack.cpp

@@ -4,7 +4,26 @@
  *  Created on: Oct 3, 2016
  *      Author: nullifiedcat
  */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
+// The code below was obtained from:
+// http://stackoverflow.com/questions/77005/how-to-generate-a-stacktrace-when-my-gcc-c-app-crashes/1925461#1925461
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#ifndef __USE_GNU
+#define __USE_GNU
+#endif
+
+#include <execinfo.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ucontext.h>
+#include <unistd.h>
 #include <visual/SDLHooks.hpp>
 #include "hack.hpp"
 #include "common.hpp"
@@ -224,9 +243,76 @@ void hack::CC_Cat(const CCommand &args)
     g_ICvar->ConsoleColorPrintf(Color(255, 0, 0, 255), "nullifiedcat\n");
 }
 
+
+
+/* This structure mirrors the one found in /usr/include/asm/ucontext.h */
+typedef struct _sig_ucontext {
+    unsigned long     uc_flags;
+    struct ucontext   *uc_link;
+    stack_t           uc_stack;
+    struct sigcontext uc_mcontext;
+    sigset_t          uc_sigmask;
+} sig_ucontext_t;
+
+void crit_err_hdlr(int sig_num, siginfo_t * info, void * ucontext) {
+    void *             array[50];
+    void *             caller_address;
+    char **            messages;
+    int                size, i;
+    sig_ucontext_t *   uc;
+
+    uc = (sig_ucontext_t *)ucontext;
+
+    /* Get the address at the time the signal was raised */
+    #if defined(__i386__) // gcc specific
+    caller_address = (void *) uc->uc_mcontext.eip; // EIP: x86 specific
+    #elif defined(__x86_64__) // gcc specific
+    caller_address = (void *) uc->uc_mcontext.rip; // RIP: x86_64 specific
+    #else
+    #error Unsupported architecture. // TODO: Add support for other arch.
+    #endif
+
+    fprintf(stderr, "\n");
+    FILE * backtraceFile;
+
+    // In this example we write the stacktrace to a file. However, we can also just fprintf to stderr (or do both).
+    passwd *pwd = getpwuid(getuid());
+    backtraceFile = fopen(strfmt("/tmp/cathook-%s-%d-segfault.log", pwd->pw_name, getpid()), "w");
+
+    if (sig_num == SIGSEGV)
+        fprintf(backtraceFile, "signal %d (%s), address is %p from %p\n",sig_num, strsignal(sig_num), info->si_addr,(void *)caller_address);
+    else
+        fprintf(backtraceFile, "signal %d (%s)\n",sig_num, strsignal(sig_num));
+
+    size = backtrace(array, 50);
+    /* overwrite sigaction with caller's address */
+    array[1] = caller_address;
+    messages = backtrace_symbols(array, size);
+    /* skip first stack frame (points here) */
+    for (i = 1; i < size && messages != NULL; ++i) {
+        fprintf(backtraceFile, "[bt]: (%d) %s\n", i, messages[i]);
+    }
+
+    fclose(backtraceFile);
+    free(messages);
+
+    exit(EXIT_FAILURE);
+}
+
+void installSignal(int __sig) {
+    struct sigaction sigact;
+    sigact.sa_sigaction = crit_err_hdlr;
+    sigact.sa_flags = SA_RESTART | SA_SIGINFO;
+    if (sigaction(__sig, &sigact, (struct sigaction *)NULL) != 0) {
+        fprintf(stderr, "error setting signal handler for %d (%s)\n",__sig, strsignal(__sig));
+        exit(EXIT_FAILURE);
+    }
+}
 void hack::Initialize()
 {
     signal(SIGPIPE, SIG_IGN);
+    installSignal(SIGSEGV);
+    installSignal(SIGABRT);
     time_injected = time(nullptr);
 /*passwd *pwd   = getpwuid(getuid());
 char *logname = strfmt("/tmp/cathook-game-stdout-%s-%u.log", pwd->pw_name,