[PATCH rtems-examples 02/23] psx_sigint: Add new example of POSIX signal and default mask

Joel Sherrill joel at rtems.org
Wed Feb 23 22:21:30 UTC 2022


---
 posix_api/Makefile                  |  1 +
 posix_api/psx_sigint/Makefile       | 20 ++++++++
 posix_api/psx_sigint/main.c         | 99 +++++++++++++++++++++++++++++++++++++
 posix_api/psx_sigint/rtems_config.c | 48 ++++++++++++++++++
 posix_api/psx_sigint/wscript        | 15 ++++++
 posix_api/wscript                   |  1 +
 6 files changed, 184 insertions(+)
 create mode 100644 posix_api/psx_sigint/Makefile
 create mode 100644 posix_api/psx_sigint/main.c
 create mode 100644 posix_api/psx_sigint/rtems_config.c
 create mode 100644 posix_api/psx_sigint/wscript

diff --git a/posix_api/Makefile b/posix_api/Makefile
index 601246c..586758a 100644
--- a/posix_api/Makefile
+++ b/posix_api/Makefile
@@ -14,5 +14,6 @@ ifeq ($(RTEMS_HAS_POSIX_API),yes)
   SUBDIRS += psx_pthread_report
   SUBDIRS += psx_rwlock_report
   SUBDIRS += psx_sched_report
+  SUBDIRS += psx_sigint
   SUBDIRS += livermore
 endif
diff --git a/posix_api/psx_sigint/Makefile b/posix_api/psx_sigint/Makefile
new file mode 100644
index 0000000..0720473
--- /dev/null
+++ b/posix_api/psx_sigint/Makefile
@@ -0,0 +1,20 @@
+#
+#  RTEMS_MAKEFILE_PATH is typically set in an environment variable
+#
+
+PGM=${ARCH}/psx_sigint.exe
+
+# C source names
+CSRCS = main.c rtems_config.c
+COBJS = $(CSRCS:%.c=${ARCH}/%.o)
+
+include $(RTEMS_MAKEFILE_PATH)/Makefile.inc
+include $(RTEMS_CUSTOM)
+include $(PROJECT_ROOT)/make/leaf.cfg
+
+OBJS= $(COBJS) $(CXXOBJS) $(ASOBJS)
+
+all:    ${ARCH} $(PGM)
+
+$(PGM): $(OBJS)
+	$(make-exe)
diff --git a/posix_api/psx_sigint/main.c b/posix_api/psx_sigint/main.c
new file mode 100644
index 0000000..3793650
--- /dev/null
+++ b/posix_api/psx_sigint/main.c
@@ -0,0 +1,99 @@
+/*
+ * A C program that does not terminate when SIGINT is generated.
+ * Normally, SIGINT is generated with ctrl-c is pressed.
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/*
+ * This program can be conditionally compiled to install the signal
+ * handler with signal() or sigaction(). The distinction is that
+ * using signal() only stays within the confines of the Standard
+ * C Library and does not assume any POSIX APIs or behavior.
+ */
+
+/* #define USE_SIGNAL */
+#define USE_SIGACTION
+
+/* Signal Handler for SIGINT */
+void sigintHandler(int signo)
+{
+  if (signo != SIGINT) {
+    fprintf(
+      stderr,
+      "signalHandler: signal != SIGINT (%d != %d)\n",
+      signo,
+      SIGINT
+    );
+    exit(1);
+  }
+#ifdef USE_SIGNAL
+  /* Reset handler to catch SIGINT next time.
+   *  Refer http://en.cppreference.com/w/c/program/signal
+   */
+  signal(SIGINT, sigintHandler);
+#endif
+
+  printf("\n Cannot be terminated using Ctrl+C \n");
+  fflush(stdout);
+}
+
+int main(int argc, char **argv)
+{
+  /*
+   * POSIX does not appear to define the default signal mask. It discusses
+   * a forked process and created thread inheriting a mask from the creating
+   * process/thread, but not the default initial signal mask.
+   *
+   * On RTEMS 4.11 and older, all signals are masked by default for both POSIX
+   *   threads and Classic API tasks. With version 5, they are enabled by
+   *   default for POSIX threads and disabled by default for Classic API tasks.
+   * On Linux, all signals are unmasked by default.
+   *
+   * The following code unmasks the signal of interest.
+   */
+#if __rtems__ && (__RTEMS_MAJOR__ < 5)
+  sigset_t old_set,new_set;
+  sigprocmask(SIG_SETMASK, NULL, &old_set);
+  /* printf( "mask=0x%08lx\n", old_set); */
+
+  sigemptyset(&new_set);
+  sigaddset(&new_set,SIGINT);
+  sigprocmask(SIG_UNBLOCK, &new_set, NULL);
+#endif
+
+#ifdef USE_SIGNAL
+  /* Set the SIGINT (Ctrl-C) signal handler to sigintHandler
+     Refer http://en.cppreference.com/w/c/program/signal */
+  signal(SIGINT, sigintHandler);
+#endif
+
+#ifdef USE_SIGACTION
+  struct sigaction new_action;
+  int              rc;
+
+  new_action.sa_handler = sigintHandler;
+  new_action.sa_flags = 0;
+  rc = sigaction(SIGINT, &new_action, NULL);
+  if (rc != 0) {
+    fprintf(stderr, "sigaction -> %s\n", strerror(errno));
+  }
+#endif
+
+  int sent_signal = 0;
+
+  while(1)
+  {
+    if (sent_signal == 0) {
+      kill(getpid(), SIGINT);
+      sent_signal = 1;
+    }
+  }
+  return 0;
+}
+
diff --git a/posix_api/psx_sigint/rtems_config.c b/posix_api/psx_sigint/rtems_config.c
new file mode 100644
index 0000000..fd0a0f8
--- /dev/null
+++ b/posix_api/psx_sigint/rtems_config.c
@@ -0,0 +1,48 @@
+/*
+ * This file contains the RTEMS Configuration for this example.
+ */
+
+/*
+ * Copyright 2018 Joel Sherrill (joel at rtems.org)
+ *
+ * This file's license is 2-clause BSD as in this distribution's LICENSE.2 file.
+ */
+
+#include <stdlib.h>
+
+int main(int argc, char **argv);
+
+static char *argv_list[] = {
+  "report",
+  ""
+};
+static void *POSIX_Init(void *arg)
+{
+  (void) arg;  /* deliberately ignored */
+
+  /*
+   * Initialize optional services
+   */
+
+  /*
+   * Could get arguments from command line or have a static set.
+   */
+  (void) main(1, argv_list);
+
+  return NULL;
+}
+
+#include <bsp.h> /* for device driver prototypes */
+
+/* NOTICE: the clock driver is explicitly disabled */
+#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+
+#define CONFIGURE_POSIX_INIT_THREAD_TABLE
+
+#define CONFIGURE_UNLIMITED_OBJECTS
+#define CONFIGURE_UNIFIED_WORK_AREAS
+#define CONFIGURE_MINIMUM_TASK_STACK_SIZE (64 * 1024)
+
+#define CONFIGURE_INIT
+#include <rtems/confdefs.h>
diff --git a/posix_api/psx_sigint/wscript b/posix_api/psx_sigint/wscript
new file mode 100644
index 0000000..e09594c
--- /dev/null
+++ b/posix_api/psx_sigint/wscript
@@ -0,0 +1,15 @@
+# Copyright 2013 Gedare Bloom (gedare at rtems.org)
+#
+# This file's license is 2-clause BSD as in this distribution's LICENSE.2 file.
+#
+
+import rtems_waf.rtems as rtems
+
+def build(bld):
+    rtems.build(bld)
+
+    bld(features = 'c cprogram',
+        target = 'psx_sigint.exe',
+        source = ['main.c','rtems_config.c'],
+        lib = ['c'])
+
diff --git a/posix_api/wscript b/posix_api/wscript
index 912063b..19b6e3e 100644
--- a/posix_api/wscript
+++ b/posix_api/wscript
@@ -17,4 +17,5 @@ def build(bld):
         bld.recurse('psx_pthread_report')
         bld.recurse('psx_rwlock_report')
         bld.recurse('psx_sched_report')
+        bld.recurse('psx_sigint')
         bld.recurse('livermore')
-- 
1.8.3.1



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