cpp: Add cpp.c module to invoke C preprocessor

Add cpp_exec func to invoke C preprocessor
which allow to change the logic in one place only.

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

1 files changed, 27 insertions, 0 deletions

diff --git a/cpp.c b/cpp.c
new file mode 100644
index 0000000..8448252
--- /dev/null
+++ b/cpp.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <libgen.h>
+
+#include "str.h"
+#include "xmalloc.h"
+
+int cpp_exec(char *in_file, char *out_file, size_t out_len)
+{
+	char cmd[256], *dir, *base;
+	char *a = xstrdup(in_file);
+	char *b = xstrdup(in_file);
+	int ret = 0;
+
+	dir = dirname(a);
+	base = basename(b);
+
+	slprintf(out_file, out_len, "%s/.tmp-%u-%s", dir, rand(), base);
+	slprintf(cmd, sizeof(cmd), "cpp -I" ETCDIRE_STRING " %s > %s",
+		 in_file, out_file);
+
+	if (system(cmd) != 0)
+		ret = -1;
+
+	xfree(a);
+	xfree(b);
+	return ret;
+}