From: guy <guy>
Date: Tue, 11 Feb 2003 07:40:09 +0000 (+0000)
Subject: Add a "pcap_lib_version()" routine to return a version string for
X-Git-Tag: libpcap-0.8-bp~82
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/e13c3504179ac3255919375b86d65c54c5238fbc

Add a "pcap_lib_version()" routine to return a version string for
libpcap; it generates the string at run time on the first call, so that
it's not a constant string - in at least some UNIXes, constant data in a
shared library is kept separate from the library code, and is bound into
applications linked with that library at link time, not at run time, so
a constant string (such as "pcap_version[]") can reflect the version of
the library with which the application was built, not the version with
which it's running.

Document it, in the hopes that vendors will be less likely to omit it
from their libpcaps (unlike "pcap_version[]", which is absent from some
vendors' libpcaps).
---

diff --git a/Makefile.in b/Makefile.in
index 0b94eb1d..ff02d47c 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -17,7 +17,7 @@
 #  WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 #  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 #
-# @(#) $Header: /tcpdump/master/libpcap/Makefile.in,v 1.90 2003-02-11 01:46:05 guy Exp $ (LBL)
+# @(#) $Header: /tcpdump/master/libpcap/Makefile.in,v 1.91 2003-02-11 07:40:09 guy Exp $ (LBL)
 
 #
 # Various configurable paths (remember to edit Makefile.in, not Makefile)
@@ -84,7 +84,7 @@ OBJ =	$(PSRC:.c=.o) $(FSRC:.c=.o) $(CSRC:.c=.o) $(GENSRC:.c=.o) # $(LIBOBJS)
 HDR =	pcap.h pcap-int.h pcap-namedb.h pcap-nit.h pcap-pf.h \
 	ethertype.h gencode.h gnuc.h
 GENHDR = \
-	tokdefs.h
+	tokdefs.h version.h
 
 TAGHDR = \
 	pcap-bpf.h
@@ -129,6 +129,11 @@ version.c: $(srcdir)/VERSION
 	@rm -f $@
 	sed -e 's/.*/char pcap_version[] = "&";/' $(srcdir)/VERSION > $@
 
+version.h: $(srcdir)/VERSION
+	@rm -f $@
+	sed -e 's/\([0-9]*\)\.[0-9]*/#define VERSION_MAJOR \1/' $(srcdir)/VERSION > $@
+	sed -e 's/[0-9]*\.\([0-9]*\)/#define VERSION_MINOR \1/' $(srcdir)/VERSION >> $@
+
 bpf_filter.c: $(srcdir)/bpf/net/bpf_filter.c
 	rm -f bpf_filter.c
 	ln -s $(srcdir)/bpf/net/bpf_filter.c bpf_filter.c
diff --git a/pcap.3 b/pcap.3
index 34917fe6..018eb1c5 100644
--- a/pcap.3
+++ b/pcap.3
@@ -1,4 +1,4 @@
-.\" @(#) $Header: /tcpdump/master/libpcap/Attic/pcap.3,v 1.45 2003-01-16 07:29:15 guy Exp $
+.\" @(#) $Header: /tcpdump/master/libpcap/Attic/pcap.3,v 1.46 2003-02-11 07:40:09 guy Exp $
 .\"
 .\" Copyright (c) 1994, 1996, 1997
 .\"	The Regents of the University of California.  All rights reserved.
@@ -96,6 +96,7 @@ int pcap_fileno(pcap_t *p)
 void pcap_perror(pcap_t *p, char *prefix)
 char *pcap_geterr(pcap_t *p)
 char *pcap_strerror(int error)
+const char *pcap_lib_version(void)
 .ft
 .LP
 .ft B
@@ -816,12 +817,10 @@ returns true if the current ``savefile'' uses a different byte order
 than the current system.
 .PP
 .B pcap_major_version()
-returns the major number of the version of the pcap used to write the
-savefile.
-.PP
+returns the major number of the file format of the savefile;
 .B pcap_minor_version()
-returns the minor number of the version of the pcap used to write the
-savefile.
+returns the minor number of the file format of the savefile.  The
+version number is stored in the header of the savefile.
 .PP
 .B pcap_file()
 returns the standard I/O stream of the ``savefile,'' if a ``savefile''
@@ -873,6 +872,10 @@ is provided in case
 .BR strerror (1)
 isn't available.
 .PP
+.B pcap_lib_version()
+returns a pointer to a string giving the version number of the libpcap
+library being used.
+.PP
 .B pcap_close()
 closes the files associated with
 .I p
diff --git a/pcap.c b/pcap.c
index cfcccf0c..4ef79146 100644
--- a/pcap.c
+++ b/pcap.c
@@ -33,7 +33,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.45 2003-01-23 07:24:52 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.46 2003-02-11 07:40:09 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -60,6 +60,7 @@ static const char rcsid[] =
 #endif
 
 #include "pcap-int.h"
+#include "version.h"
 
 int
 pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
@@ -596,3 +597,25 @@ pcap_close(pcap_t *p)
 	pcap_freecode(&p->fcode);
 	free(p);
 }
+
+/*
+ * Generate the version string at run time, so that if libpcap is a
+ * shared library, it reflects the version of the library with
+ * which the program calling "pcap_lib_version()" is running, not
+ * the version with which it was built (on at least some UNIXes,
+ * constant data is linked in at build time).
+ */
+const char *
+pcap_lib_version(void)
+{
+	static char version_string[10+1+10+1];
+
+	if (version_string[0] == '\0') {
+		/*
+		 * We haven't built the string yet.
+		 */
+		snprintf(version_string, sizeof (version_string), "%u.%u",
+		    VERSION_MAJOR, VERSION_MINOR);
+	}
+	return (version_string);
+}
diff --git a/pcap.h b/pcap.h
index fbd3907f..146f1c1f 100644
--- a/pcap.h
+++ b/pcap.h
@@ -31,7 +31,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * @(#) $Header: /tcpdump/master/libpcap/pcap.h,v 1.42 2003-02-11 01:46:06 guy Exp $ (LBL)
+ * @(#) $Header: /tcpdump/master/libpcap/pcap.h,v 1.43 2003-02-11 07:40:09 guy Exp $ (LBL)
  */
 
 #ifndef lib_pcap_h
@@ -211,6 +211,8 @@ void	pcap_dump(u_char *, const struct pcap_pkthdr *, const u_char *);
 int	pcap_findalldevs(pcap_if_t **, char *);
 void	pcap_freealldevs(pcap_if_t *);
 
+const char *pcap_lib_version(void);
+
 /* XXX this guy lives in the bpf tree */
 u_int	bpf_filter(struct bpf_insn *, u_char *, u_int, u_int);
 int	bpf_validate(struct bpf_insn *f, int len);