jack_interposer.c

   1 // needed to use RTLD_NEXT from dlfcn.h
   2 #define _GNU_SOURCE
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <stdbool.h>
   7 #include <dlfcn.h>
   8 #include <poll.h>
   9 #include <jack/jack.h>
  10 #include <stdarg.h>
  11
  12 #define ABORT_ON_VIOLATION 1
  13
  14 // is set to 'true' when entering the process-callback and to 'false' when
  15 // leaving it. When set to 'true', calls to non-realtime functions will
  16 // cause warnings/errors.
  17 //
  18 // This assumes there is only 1 thread running at a time, thus introducing
  19 // the limitation that jack_interposer is only usable on single-CPU machines
  20 // (or machines configured to run the application under test on only 1 CPU).
  21 bool in_rt = false;
  22
  23 #include "checkers.c"
  24
  25 JackProcessCallback real_process_callback;
  26
  27 int fprintf(FILE *stream, const char *format, ...)
  28 {
  29   va_list ap;
  30   va_start(ap, format);
  31   return vfprintf(stream, format, ap);
  32 }
  33
  34 int printf(const char *format, ...)
  35 {
  36   va_list ap;
  37   va_start(ap, format);
  38   return vprintf(format, ap);
  39 }
  40
  41 int pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex, const struct timespec* abstime)
  42 {
  43   static int (*func)(pthread_cond_t*, pthread_mutex_t*, const struct timespec* abstime);
  44
  45   if (in_rt)
  46   {
  47     printf("pthread_cond_timedwait() is called while in rt section\n");
  48 #if ABORT_ON_VIOLATION
  49     abort();
  50 #endif
  51   }
  52
  53   if(!func)
  54     //func = (int (*)(pthread_cond_t*, pthread_mutex_t*)) dlsym(RTLD_NEXT, "pthread_cond_wait");
  55     // see http://forums.novell.com/novell-product-support-forums/suse-linux-enterprise-server-sles/sles-configure-administer/385705-sles-10-2-java-hung-calling-pthread_cond_timedwait.html
  56     func = (int (*)()) dlvsym(RTLD_NEXT, "pthread_cond_timedwait", "GLIBC_2.3.2");
  57   if (func == NULL)
  58   {
  59     fprintf(stderr, "Error dlsym'ing\n");
  60     abort();
  61   }
  62   return(func(cond, mutex, abstime));
  63 }
  64
  65
  66 int pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex)
  67 {
  68   static int (*func)(pthread_cond_t*, pthread_mutex_t*);
  69
  70   if (in_rt)
  71   {
  72     printf("pthread_cond_wait() is called while in rt section\n");
  73 #if ABORT_ON_VIOLATION
  74     abort();
  75 #endif
  76   }
  77
  78   if(!func)
  79     //func = (int (*)(pthread_cond_t*, pthread_mutex_t*)) dlsym(RTLD_NEXT, "pthread_cond_wait");
  80     // see http://forums.novell.com/novell-product-support-forums/suse-linux-enterprise-server-sles/sles-configure-administer/385705-sles-10-2-java-hung-calling-pthread_cond_timedwait.html
  81     func = (int (*)(pthread_cond_t*, pthread_mutex_t*)) dlvsym(RTLD_NEXT, "pthread_cond_wait", "GLIBC_2.3.2");
  82   if (func == NULL)
  83   {
  84     fprintf(stderr, "Error dlsym'ing\n");
  85     abort();
  86   }
  87   return(func(cond, mutex));
  88 }
  89
  90 int interposed_process_callback(jack_nframes_t nframes, void* arg)
  91 {
  92   int result;
  93
  94   in_rt = true;
  95
  96   result = real_process_callback(nframes, arg);
  97
  98   in_rt = false;
  99
 100   return result;
 101 }
 102
 103 int jack_set_process_callback(jack_client_t* client,
 104         JackProcessCallback process_callback, void* arg)
 105 {
 106   printf("hi!\n");
 107
 108   static int (*func)() = NULL;
 109   int result;
 110
 111   if(!func)
 112     func = (int(*)()) dlsym(RTLD_NEXT, "jack_set_process_callback");
 113   if(!func)
 114   {
 115     fprintf(stderr, "Error dlsym'ing jack_set_process_callback\n");
 116     abort();
 117   }
 118
 119   real_process_callback = process_callback;
 120
 121   result = func(client, interposed_process_callback, arg);
 122
 123   printf("Result is %d\n", result);
 124
 125   return result;
 126 }