Commit ae8d36db authored by George Kadianakis's avatar George Kadianakis
Browse files

Merge branch 'tor-github/pr/1302'

parents fc760c50 749c2e17

changes/bug31614

0 → 100644
+9 −0
Original line number Diff line number Diff line 
  o Minor bugfixes (logging):

    - Disable backtrace signal handlers when shutting down tor.

      Fixes bug 31614; bugfix on 0.2.5.2-alpha.

    - Add a missing check for HAVE_PTHREAD_H, because the backtrace code uses

      mutexes. Fixes bug 31614; bugfix on 0.2.5.2-alpha.

  o Documentation:

    - Explain why we can't destroy the backtrace buffer mutex. Explain why

      we don't need to destroy the log mutex.

      Closes ticket 31736.

src/lib/err/backtrace.c

+23 −3
Original line number Diff line number Diff line
@@ -57,7 +57,8 @@ 
#include "lib/err/torerr.h"



#if defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE) && \

  defined(HAVE_BACKTRACE_SYMBOLS_FD) && defined(HAVE_SIGACTION)

  defined(HAVE_BACKTRACE_SYMBOLS_FD) && defined(HAVE_SIGACTION) && \

  defined(HAVE_PTHREAD_H)

#define USE_BACKTRACE

#endif
@@ -190,13 +191,15 @@ dump_stack_symbols_to_error_fds(void) 
    backtrace_symbols_fd(cb_buf, (int)depth, fds[i]);

}



/* The signals that we want our backtrace handler to trap */

static int trap_signals[] = { SIGSEGV, SIGILL, SIGFPE, SIGBUS, SIGSYS,

  SIGIO, -1 };



/** Install signal handlers as needed so that when we crash, we produce a

 * useful stack trace. Return 0 on success, -errno on failure. */

static int

install_bt_handler(void)

{

  int trap_signals[] = { SIGSEGV, SIGILL, SIGFPE, SIGBUS, SIGSYS,

                         SIGIO, -1 };

  int i, rv=0;



  struct sigaction sa;
@@ -232,6 +235,23 @@ install_bt_handler(void) 
static void

remove_bt_handler(void)

{

  int i;



  struct sigaction sa;



  memset(&sa, 0, sizeof(sa));

  sa.sa_handler = SIG_DFL;

  sigfillset(&sa.sa_mask);



  for (i = 0; trap_signals[i] >= 0; ++i) {

    /* remove_bt_handler() is called on shutdown, from low-level code.

     * It's not a fatal error, so we just ignore it. */

    (void)sigaction(trap_signals[i], &sa, NULL);

  }



  /* cb_buf_mutex is statically initialised, so we can not destroy it.

   * If we destroy it, and then re-initialise tor, all our backtraces will

   * fail. */

}

#endif /* defined(USE_BACKTRACE) */

src/lib/log/log.c

+4 −1
Original line number Diff line number Diff line
@@ -832,7 +832,10 @@ logs_free_all(void) 
  }



  /* We _could_ destroy the log mutex here, but that would screw up any logs

   * that happened between here and the end of execution. */

   * that happened between here and the end of execution.

   * If tor is re-initialized, log_mutex_initialized will still be 1. So we

   * won't trigger any undefined behaviour by trying to re-initialize the

   * log mutex. */

}



/** Close signal-safe log files.

src/lib/sandbox/sandbox.c

+1 −0
Original line number Diff line number Diff line
@@ -294,6 +294,7 @@ sb_rt_sigaction(scmp_filter_ctx ctx, sandbox_cfg_t *filter) 
  unsigned i;

  int rc;

  int param[] = { SIGINT, SIGTERM, SIGPIPE, SIGUSR1, SIGUSR2, SIGHUP, SIGCHLD,

                  SIGSEGV, SIGILL, SIGFPE, SIGBUS, SIGSYS, SIGIO,

#ifdef SIGXFSZ

      SIGXFSZ

#endif