cpp: Allow to pass additional cpp options

Extend cpp_exec function with args parameter to
specify additional cpp options (like -D).

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

4 files changed, 33 insertions, 12 deletions

diff --git a/bpf_parser.y b/bpf_parser.y
index 003c031..7331cc5 100644
--- a/bpf_parser.y
+++ b/bpf_parser.y
@@ -745,7 +745,7 @@ int compile_filter(char *file, int verbose, int bypass, int format,
 	memset(tmp_file, 0, sizeof(tmp_file));
 
 	if (invoke_cpp) {
-		ret = cpp_exec(file, tmp_file, sizeof(tmp_file));
+		ret = cpp_exec(file, tmp_file, sizeof(tmp_file), NULL);
 		if (ret) {
 			fprintf(stderr, "Failed to invoke C preprocessor!\n");
 			goto exit;
diff --git a/cpp.c b/cpp.c
index d4ec2a6..8e03209 100644
--- a/cpp.c
+++ b/cpp.c
@@ -5,25 +5,46 @@
 #include "proc.h"
 #include "xmalloc.h"
 
-int cpp_exec(char *in_file, char *out_file, size_t out_len)
+static size_t argv_len(char **argv)
 {
+	size_t len = 0;
+
+	for (; argv && *argv; argv++)
+		len++;
+
+	return len;
+}
+
+int cpp_exec(char *in_file, char *out_file, size_t out_len, char **argv)
+{
+	size_t argc = 7 + argv_len(argv);
 	char *tmp = xstrdup(in_file);
-	char *argv[7] = {
-		"cpp",
-		"-I", ETCDIRE_STRING,
-		"-o", out_file,
-		in_file,
-		NULL,
-	};
+	char **cpp_argv;
 	int ret = 0;
 	char *base;
+	unsigned int i = 0;
 
 	base = basename(tmp);
 	slprintf(out_file, out_len, "/tmp/.tmp-%u-%s", rand(), base);
 
-	if (proc_exec("cpp", argv))
+	cpp_argv = xmalloc(argc * sizeof(char *));
+
+	cpp_argv[i++] = "cpp";
+
+	for (; argv && *argv; argv++, i++)
+		cpp_argv[i] = *argv;
+
+	cpp_argv[i++] = "-I";
+	cpp_argv[i++] = ETCDIRE_STRING;
+	cpp_argv[i++] = "-o";
+	cpp_argv[i++] = out_file;
+	cpp_argv[i++] = in_file;
+	cpp_argv[i++] = NULL;
+
+	if (proc_exec("cpp", cpp_argv))
 		ret = -1;
 
+	xfree(cpp_argv);
 	xfree(tmp);
 	return ret;
 }
diff --git a/cpp.h b/cpp.h
index a3e295d..45c42ac 100644
--- a/cpp.h
+++ b/cpp.h
@@ -1,6 +1,6 @@
 #ifndef CPP_H
 #define CPP_H
 
-extern int cpp_exec(char *in_file, char *out_file, size_t out_len);
+extern int cpp_exec(char *in_file, char *out_file, size_t out_len, char **argv);
 
 #endif
diff --git a/trafgen_parser.y b/trafgen_parser.y
index 44751ab..8a0f3b7 100644
--- a/trafgen_parser.y
+++ b/trafgen_parser.y
@@ -599,7 +599,7 @@ void compile_packets(char *file, bool verbose, unsigned int cpu, bool invoke_cpp
 	our_cpu = cpu;
 
 	if (invoke_cpp) {
-		if (cpp_exec(file, tmp_file, sizeof(tmp_file))) {
+		if (cpp_exec(file, tmp_file, sizeof(tmp_file), NULL)) {
 			fprintf(stderr, "Failed to invoke C preprocessor!\n");
 			goto err;
 		}