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Safe accesses of global arrays in signal handlers?

Cross-posted to 2 groups.

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Hello,

A secure programming guideline contains the following information.

https://www.securecoding.cert.org/confluence/display/seccode/SIG31-C.+Do+not+access+or+modify+shared+objects+in+signal+handlers
:
'Accessing or modifying shared objects in signal handlers can result in race
conditions that can leave data in an inconsistent state. The exception to this
rule is the ability to read and write to variables of volatile sig_atomic_t.
...
It is important to note that the behavior of a program that accesses an object
of any other type from a signal handler is undefined.'


I interpret this description in the way that there are risks for the portable
use of a shared variable which has got a data type like "array" within a signal
handler.
http://en.wikipedia.org/wiki/Array_data_type


Source code example:
  pthread_mutex_t my_lock = PTHREAD_MUTEX_INITIALIZER;
  struct my_element my_list[MY_ARRAY_SIZE];

  void my_status_log(int number)
  {
   int result = pthread_mutex_lock(&my_lock);

   if (result) exit(result);

   if (  my_list[number - 1].catched
      && printf("Signal %d was received.", number) < 22)
      perror("printf");

   result = pthread_mutex_unlock(&my_lock);

   if (result) exit(result);
  }


  static void my_signal_handler(int number)
  {
   struct my_data * pointer = my_list[number - 1].context;

   if (!pointer) return;

   my_list[number - 1].catched = 1;

   /* Call more functions eventually ... */
  }


I would appreciate your advices for the clarification of the involved
implementation details. Would you like to suggest any solutions for such an use
case?

Regards,
Markus

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Thread

Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-25 08:01 +0200
  Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-25 12:15 +0100
    Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-27 11:20 +0200
      Re: Safe accesses of global arrays in signal handlers? Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-09-27 13:23 +0100
        Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-28 13:25 +0200
      Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-27 13:35 +0100
        Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-28 13:48 +0200
          Re: Safe accesses of global arrays in signal handlers? Johann Klammer <klammerj@NOSPAM.a1.net> - 2012-09-28 18:34 +0200
            Re: Safe accesses of global arrays in signal handlers? scott@slp53.sl.home (Scott Lurndal) - 2012-09-28 17:54 +0000
          Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-28 18:26 +0100
            Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-29 13:44 +0200
              Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-29 20:37 +0100
                Re: Safe accesses of global arrays in signal handlers? William Ahern <william@wilbur.25thandClement.com> - 2012-09-29 17:31 -0700
                Signal handlers writing into pipes Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 13:21 +0200
                Re: Safe accesses of global arrays in signal handlers? Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-10-01 18:04 +0100
                Signal handlers writing into pipes Markus Elfring <Markus.Elfring@web.de> - 2012-10-03 16:36 +0200
                Re: Signal handlers writing into pipes Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-10-03 17:07 +0100
                Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 13:12 +0200
                Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-30 20:46 +0100
        Re: Safe accesses of global arrays in signal handlers? Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2012-09-28 13:39 +0100
        Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-29 13:15 +0200
          Re: Safe accesses of global arrays in signal handlers? William Ahern <william@wilbur.25thandClement.com> - 2012-09-29 17:42 -0700
            Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 14:04 +0200
  Re: Safe accesses of global arrays in signal handlers? Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-09-25 13:27 +0100

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