Add utility functions to get the software version string.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

makefile

@@ -30,7 +30,8 @@ CFLAGS	= -Wall $(VER) $(INC) $(DEBUG) $(FEAT_CFLAGS) $(EXTRA_CFLAGS)
 LDLIBS	= -lm -lrt $(EXTRA_LDFLAGS)
 PRG	= ptp4l pmc phc2sys hwstamp_ctl
 OBJ	= bmc.o clock.o config.o fsm.o ptp4l.o mave.o msg.o phc.o pi.o port.o \
- print.o raw.o servo.o sk.o tlv.o tmtab.o transport.o udp.o udp6.o uds.o util.o
+ print.o raw.o servo.o sk.o tlv.o tmtab.o transport.o udp.o udp6.o uds.o util.o \
+ version.o
 
 OBJECTS	= $(OBJ) pmc.o phc2sys.o hwstamp_ctl.o sysoff.o
 SRC	= $(OBJECTS:.o=.c)
@@ -54,6 +55,15 @@ phc2sys: phc2sys.o sk.o sysoff.o print.o
 
 hwstamp_ctl: hwstamp_ctl.o
 
+version.o: .version version.sh $(filter-out version.d,$(DEPEND))
+
+.version: force
+	@echo $(version) > .version.new; \
+	cmp -s .version .version.new || cp .version.new .version; \
+	rm -f .version.new;
+
+force:
+
 install: $(PRG)
 	mkdir -p $(sbindir) $(man8dir)
 	install $(PRG) $(sbindir)
@@ -64,6 +74,7 @@ clean:
 
 distclean: clean
 	rm -f $(PRG)
+	rm -f .version
 
 # Implicit rule to generate a C source file's dependencies.
 %.d: %.c
@@ -78,3 +89,5 @@ ifneq ($(MAKECMDGOALS), distclean)
 -include $(DEPEND)
 endif
 endif
+
+.PHONY: all force clean distclean

version.c

@@ -0,0 +1,35 @@
+/**
+ * @file version.c
+ * @brief Provides a software version string.
+ * @note Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "version.h"
+
+#define STRINGIFY_(x) #x
+#define STRINGIFY(x) STRINGIFY_(x)
+
+static const char *version = STRINGIFY(VER);
+
+void version_show(FILE *fp)
+{
+	fprintf(fp, "%s\n", version);
+}
+
+const char *version_string(void)
+{
+	return version;
+}

version.h

@@ -0,0 +1,37 @@
+/**
+ * @file version.h
+ * @brief Provides a software version string.
+ * @note Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef HAVE_VERSION_H
+#define HAVE_VERSION_H
+
+#include <stdio.h>
+
+/**
+ * Print the software version string into the given file.
+ * @param fp  File pointer open for writing.
+ */
+void version_show(FILE *fp);
+
+/**
+ * Provide the software version as a human readable string.
+ * @return  Pointer to a static global buffer holding the result.
+ */
+const char *version_string(void);
+
+#endif