When attaching a "bpf_program" to a "pcap_t" to use as a userland

filter, always attach a copy, as "pcap-linux.c" does; that way, after a
program uses "pcap_setfilter()", it can safely use "pcap_freecode()" to
free up the BPF instructions allocated by "pcap_compile()".  Also,
always free it up when the "pcap_t" is closed.

Get rid of the "pcap_t *" argument to "pcap_freecode()", as it's not
necessary.

Document "pcap_freecode()", for the benefit of programs that might
repeatedly compile filter programs and attach them, so that they can
free them up after attaching them and avoid leaking memory for them.

1 files changed, 33 insertions, 1 deletions

diff --git a/optimize.c b/optimize.c
index c39f899..fe2c2ca 100644
--- a/optimize.c
+++ b/optimize.c
@@ -22,7 +22,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.64 2000-09-06 07:40:03 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.65 2000-10-28 00:01:27 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -36,6 +36,8 @@ static const char rcsid[] =
 #include <stdlib.h>
 #include <memory.h>
 
+#include <errno.h>
+
 #include "pcap-int.h"
 
 #include "gencode.h"
@@ -2077,6 +2079,36 @@ icode_to_fcode(root, lenp)
 	return fp;
 }
 
+/*
+ * Make a copy of a BPF program and put it in the "fcode" member of
+ * a "pcap_t".
+ *
+ * If we fail to allocate memory for the copy, fill in the "errbuf"
+ * member of the "pcap_t" with an error message, and return -1;
+ * otherwise, return 0.
+ */
+int
+install_bpf_program(pcap_t *p, struct bpf_program *fp)
+{
+	size_t prog_size;
+
+	/*
+	 * Free up any already installed program.
+	 */
+	pcap_freecode(&p->fcode);
+
+	prog_size = sizeof(*fp->bf_insns) * fp->bf_len;
+	p->fcode.bf_len = fp->bf_len;
+	p->fcode.bf_insns = (struct bpf_insn *)malloc(prog_size);
+	if (p->fcode.bf_insns == NULL) {
+		snprintf(p->errbuf, sizeof(p->errbuf),
+			 "malloc: %s", pcap_strerror(errno));
+		return (-1);
+	}
+	memcpy(p->fcode.bf_insns, fp->bf_insns, prog_size);
+	return (0);
+}
+
 #ifdef BDEBUG
 static void
 opt_dump(root)