source: rtems/testsuites/support/src/locked_print.c @ ac2bb464

4.11
Last change on this file since ac2bb464 was ac2bb464, checked in by Sebastian Huber <sebastian.huber@…>, on May 31, 2013 at 11:56:56 AM

smptests: Use priority ceiling for locked print

In case the printf() blocks on a semaphore it was possible to end up in
a livelock.

  • Property mode set to 100644
File size: 2.1 KB
Line 
1/*
2 *  COPYRIGHT (c) 1989-2011.
3 *  On-Line Applications Research Corporation (OAR).
4 *
5 *  The license and distribution terms for this file may be
6 *  found in the file LICENSE in this distribution or at
7 *  http://www.rtems.com/license/LICENSE.
8 */
9
10#ifdef HAVE_CONFIG_H
11#include "config.h"
12#endif
13
14#include <rtems.h>
15#include <rtems/system.h>
16#include <sys/types.h>
17#include <string.h>
18#include <stdarg.h>
19
20#include "tmacros.h"
21
22static rtems_id locked_print_semaphore;      /* synchronisation semaphore */ 
23
24void locked_print_initialize(void)
25{
26  rtems_status_code sc;
27  static            bool initted = false;
28
29  if ( initted )
30    return;
31
32  initted = true;
33
34  /* Create/verify synchronisation semaphore */
35  sc = rtems_semaphore_create(
36    rtems_build_name ('S', 'E', 'M', '1'),
37    1,                                             
38    RTEMS_LOCAL                   |
39    RTEMS_BINARY_SEMAPHORE |
40    RTEMS_PRIORITY_CEILING |
41    RTEMS_PRIORITY,
42    1,
43    &locked_print_semaphore
44  );
45  directive_failed( sc, "rtems_semaphore_create" );
46}
47
48void locked_printf(const char *fmt, ...) {
49  va_list           ap;       /* points to each unnamed argument in turn */
50  rtems_status_code sc;
51
52  locked_print_initialize();
53
54  /* Lock semaphore without releasing the cpu */
55  do {
56    sc = rtems_semaphore_obtain( locked_print_semaphore, RTEMS_NO_WAIT, 0 );
57  } while (sc != RTEMS_SUCCESSFUL );
58
59
60  va_start(ap, fmt); /* make ap point to 1st unnamed arg */
61  vprintf(fmt, ap);
62  va_end(ap);        /* clean up when done */
63
64  /* Release the semaphore  */
65  sc = rtems_semaphore_release( locked_print_semaphore );
66} 
67
68void locked_printk(const char *fmt, ...) {
69  va_list           ap;       /* points to each unnamed argument in turn */
70  rtems_status_code sc;
71
72
73  locked_print_initialize();
74
75  /* Lock semaphore without releasing the cpu */
76  do {
77    sc = rtems_semaphore_obtain( locked_print_semaphore, RTEMS_NO_WAIT, 0 );
78  } while (sc != RTEMS_SUCCESSFUL );
79
80  va_start(ap, fmt); /* make ap point to 1st unnamed arg */
81  vprintk(fmt, ap);
82  va_end(ap);        /* clean up when done */
83
84  /* Release the semaphore  */
85  sc = rtems_semaphore_release( locked_print_semaphore );
86} 
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