api: extend BPF export API to write to a memory buffer

The API to export to a fd is helpful, but for tools that want to
generate & read the BPF program, outputting to a buffer would be
much more helpful.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Reviewed-by: Tom Hromatka <tom.hromatka@oracle.com>
[PM: rename seccomp_export_bpf_buf() to seccomp_export_bpf_mem()]
[PM: 'make check-syntax' fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/seccomp.h.in b/include/seccomp.h.in
index 333a89c..6f836fb 100644
--- a/include/seccomp.h.in
+++ b/include/seccomp.h.in
@@ -25,6 +25,7 @@
 
 #include <elf.h>
 #include <inttypes.h>
+#include <stdlib.h>
 #include <asm/unistd.h>
 #include <linux/audit.h>
 #include <linux/types.h>
@@ -816,6 +817,19 @@ int seccomp_export_pfc(const scmp_filter_ctx ctx, int fd);
  */
 int seccomp_export_bpf(const scmp_filter_ctx ctx, int fd);
 
+/**
+ * Generate seccomp Berkeley Packet Filter (BPF) code and export it to a buffer
+ * @param ctx the filter context
+ * @param buf the destination buffer
+ * @param len on input the length of the buffer, on output the number of bytes
+ * in the program
+ *
+ * This function generates seccomp Berkeley Packer Filter (BPF) code and writes
+ * it to the given buffer.  Returns zero on success, negative values on failure.
+ *
+ */
+int seccomp_export_bpf_mem(const scmp_filter_ctx ctx, void *buf, size_t *len);
+
 /*
  * pseudo syscall definitions
  */