-
-
-// PrintStackTrace - In the case of a program crash or fault, print out a stack
-// trace so that the user has an indication of why and where we died.
-//
-// On glibc systems we have the 'backtrace' function, which works nicely, but
-// doesn't demangle symbols. In order to backtrace symbols, we fork and exec a
-// 'c++filt' process to do the demangling. This seems like the simplest and
-// most robust solution when we can't allocate memory (such as in a signal
-// handler). If we can't find 'c++filt', we fallback to printing mangled names.
-//
-static void PrintStackTrace() {
-#ifdef HAVE_BACKTRACE
- // Use backtrace() to output a backtrace on Linux systems with glibc.
- int depth = backtrace(StackTrace, sizeof(StackTrace)/sizeof(StackTrace[0]));
-
- // Create a one-way unix pipe. The backtracing process writes to PipeFDs[1],
- // the c++filt process reads from PipeFDs[0].
- int PipeFDs[2];
- if (pipe(PipeFDs)) {
- backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
- return;
- }
-
- switch (pid_t ChildPID = fork()) {
- case -1: // Error forking, print mangled stack trace
- close(PipeFDs[0]);
- close(PipeFDs[1]);
- backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
- return;
- default: // backtracing process
- close(PipeFDs[0]); // Close the reader side.
-
- // Print the mangled backtrace into the pipe.
- backtrace_symbols_fd(StackTrace, depth, PipeFDs[1]);
- close(PipeFDs[1]); // We are done writing.
- while (waitpid(ChildPID, 0, 0) == -1)
- if (errno != EINTR) break;
- return;
-
- case 0: // c++filt process
- close(PipeFDs[1]); // Close the writer side.
- dup2(PipeFDs[0], 0); // Read from standard input
- close(PipeFDs[0]); // Close the old descriptor
- dup2(2, 1); // Revector stdout -> stderr
-
- // Try to run c++filt or gc++filt. If neither is found, call back on 'cat'
- // to print the mangled stack trace. If we can't find cat, just exit.
- execlp("c++filt", "c++filt", 0);
- execlp("gc++filt", "gc++filt", 0);
- execlp("cat", "cat", 0);
- execlp("/bin/cat", "cat", 0);
- exit(0);
- }