cpp: Use new proc_exec function to invoke cpp

Replace 'system' call by proc_exec function from proc.c
module. It allows to easy extend cpp invoking with additional
options (like -D) in more secure way.

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

2 files changed, 11 insertions, 5 deletions

diff --git a/bpfc/Makefile b/bpfc/Makefile
index f011706..7e6fd45 100644
--- a/bpfc/Makefile
+++ b/bpfc/Makefile
@@ -7,6 +7,7 @@ bpfc-objs =	xmalloc.o \
 		bpf_parser.tab.o \
 		die.o \
 		sysctl.o \
+		proc.o \
 		cpp.o \
 		bpfc.o
 
diff --git a/cpp.c b/cpp.c
index 6734eac..d4ec2a6 100644
--- a/cpp.c
+++ b/cpp.c
@@ -2,21 +2,26 @@
 #include <libgen.h>
 
 #include "str.h"
+#include "proc.h"
 #include "xmalloc.h"
 
 int cpp_exec(char *in_file, char *out_file, size_t out_len)
 {
 	char *tmp = xstrdup(in_file);
-	char cmd[256], *base;
+	char *argv[7] = {
+		"cpp",
+		"-I", ETCDIRE_STRING,
+		"-o", out_file,
+		in_file,
+		NULL,
+	};
 	int ret = 0;
+	char *base;
 
 	base = basename(tmp);
-
 	slprintf(out_file, out_len, "/tmp/.tmp-%u-%s", rand(), base);
-	slprintf(cmd, sizeof(cmd), "cpp -I" ETCDIRE_STRING " %s > %s",
-		 in_file, out_file);
 
-	if (system(cmd) != 0)
+	if (proc_exec("cpp", argv))
 		ret = -1;
 
 	xfree(tmp);