bpftool, selftests/bpf: Embed object file inside skeleton

Embed contents of BPF object file used for BPF skeleton generation inside
skeleton itself. This allows to keep BPF object file and its skeleton in sync
at all times, and simpifies skeleton instantiation.

Also switch existing selftests to not require BPF_EMBED_OBJ anymore.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191218052552.2915188-2-andriin@fb.com

1 files changed, 143 insertions, 89 deletions

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index f70088b4c19b..8d93c8f90f82 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -16,6 +16,7 @@
 #include <libbpf.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/mman.h>
 #include <unistd.h>
 
 #include "btf.h"
@@ -261,14 +262,16 @@ static int codegen(const char *template, ...)
 static int do_skeleton(int argc, char **argv)
 {
 	char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
-	size_t i, map_cnt = 0, prog_cnt = 0;
-	char obj_name[MAX_OBJ_NAME_LEN];
+	size_t i, map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
+	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
+	char obj_name[MAX_OBJ_NAME_LEN], *obj_data;
+	struct bpf_object *obj = NULL;
 	const char *file, *ident;
 	struct bpf_program *prog;
-	struct bpf_object *obj;
+	int fd, len, err = -1;
 	struct bpf_map *map;
 	struct btf *btf;
-	int err = -1;
+	struct stat st;
 
 	if (!REQ_ARGS(1)) {
 		usage();
@@ -281,14 +284,31 @@ static int do_skeleton(int argc, char **argv)
 		return -1;
 	}
 
-	obj = bpf_object__open_file(file, NULL);
-	if (IS_ERR(obj)) {
-		p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
+	if (stat(file, &st)) {
+		p_err("failed to stat() %s: %s", file, strerror(errno));
 		return -1;
 	}
-
+	file_sz = st.st_size;
+	mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
+	fd = open(file, O_RDONLY);
+	if (fd < 0) {
+		p_err("failed to open() %s: %s", file, strerror(errno));
+		return -1;
+	}
+	obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
+	if (obj_data == MAP_FAILED) {
+		obj_data = NULL;
+		p_err("failed to mmap() %s: %s", file, strerror(errno));
+		goto out;
+	}
 	get_obj_name(obj_name, file);
-	get_header_guard(header_guard, obj_name);
+	opts.object_name = obj_name;
+	obj = bpf_object__open_mem(obj_data, file_sz, &opts);
+	if (IS_ERR(obj)) {
+		obj = NULL;
+		p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
+		goto out;
+	}
 
 	bpf_object__for_each_map(map, obj) {
 		ident = get_map_ident(map);
@@ -303,8 +323,11 @@ static int do_skeleton(int argc, char **argv)
 		prog_cnt++;
 	}
 
+	get_header_guard(header_guard, obj_name);
 	codegen("\
 		\n\
+		/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */   \n\
+									    \n\
 		/* THIS FILE IS AUTOGENERATED! */			    \n\
 		#ifndef %2$s						    \n\
 		#define %2$s						    \n\
@@ -356,19 +379,95 @@ static int do_skeleton(int argc, char **argv)
 		\n\
 		};							    \n\
 									    \n\
-		static inline struct bpf_object_skeleton *		    \n\
-		%1$s__create_skeleton(struct %1$s *obj, struct bpf_embed_data *embed)\n\
+		static void						    \n\
+		%1$s__destroy(struct %1$s *obj)				    \n\
+		{							    \n\
+			if (!obj)					    \n\
+				return;					    \n\
+			if (obj->skeleton)				    \n\
+				bpf_object__destroy_skeleton(obj->skeleton);\n\
+			free(obj);					    \n\
+		}							    \n\
+									    \n\
+		static inline int					    \n\
+		%1$s__create_skeleton(struct %1$s *obj);		    \n\
+									    \n\
+		static inline struct %1$s *				    \n\
+		%1$s__open_opts(const struct bpf_object_open_opts *opts)    \n\
+		{							    \n\
+			struct %1$s *obj;				    \n\
+									    \n\
+			obj = calloc(1, sizeof(*obj));			    \n\
+			if (!obj)					    \n\
+				return NULL;				    \n\
+			if (%1$s__create_skeleton(obj))			    \n\
+				goto err;				    \n\
+			if (bpf_object__open_skeleton(obj->skeleton, opts)) \n\
+				goto err;				    \n\
+									    \n\
+			return obj;					    \n\
+		err:							    \n\
+			%1$s__destroy(obj);				    \n\
+			return NULL;					    \n\
+		}							    \n\
+									    \n\
+		static inline struct %1$s *				    \n\
+		%1$s__open(void)					    \n\
+		{							    \n\
+			return %1$s__open_opts(NULL);			    \n\
+		}							    \n\
+									    \n\
+		static inline int					    \n\
+		%1$s__load(struct %1$s *obj)				    \n\
+		{							    \n\
+			return bpf_object__load_skeleton(obj->skeleton);    \n\
+		}							    \n\
+									    \n\
+		static inline struct %1$s *				    \n\
+		%1$s__open_and_load(void)				    \n\
+		{							    \n\
+			struct %1$s *obj;				    \n\
+									    \n\
+			obj = %1$s__open();				    \n\
+			if (!obj)					    \n\
+				return NULL;				    \n\
+			if (%1$s__load(obj)) {				    \n\
+				%1$s__destroy(obj);			    \n\
+				return NULL;				    \n\
+			}						    \n\
+			return obj;					    \n\
+		}							    \n\
+									    \n\
+		static inline int					    \n\
+		%1$s__attach(struct %1$s *obj)				    \n\
+		{							    \n\
+			return bpf_object__attach_skeleton(obj->skeleton);  \n\
+		}							    \n\
+									    \n\
+		static inline void					    \n\
+		%1$s__detach(struct %1$s *obj)				    \n\
+		{							    \n\
+			return bpf_object__detach_skeleton(obj->skeleton);  \n\
+		}							    \n\
+		",
+		obj_name
+	);
+
+	codegen("\
+		\n\
+									    \n\
+		static inline int					    \n\
+		%1$s__create_skeleton(struct %1$s *obj)			    \n\
 		{							    \n\
 			struct bpf_object_skeleton *s;			    \n\
 									    \n\
 			s = calloc(1, sizeof(*s));			    \n\
 			if (!s)						    \n\
-				return NULL;				    \n\
+				return -1;				    \n\
+			obj->skeleton = s;				    \n\
 									    \n\
 			s->sz = sizeof(*s);				    \n\
 			s->name = \"%1$s\";				    \n\
-			s->data = embed->data;				    \n\
-			s->data_sz = embed->size;			    \n\
 			s->obj = &obj->obj;				    \n\
 		",
 		obj_name
@@ -438,90 +537,45 @@ static int do_skeleton(int argc, char **argv)
 	codegen("\
 		\n\
 									    \n\
-			return s;					    \n\
-		err:							    \n\
-			bpf_object__destroy_skeleton(s);		    \n\
-			return NULL;					    \n\
-		}							    \n\
-									    \n\
-		static void						    \n\
-		%1$s__destroy(struct %1$s *obj)				    \n\
-		{							    \n\
-			if (!obj)					    \n\
-				return;					    \n\
-			if (obj->skeleton)				    \n\
-				bpf_object__destroy_skeleton(obj->skeleton);\n\
-			free(obj);					    \n\
-		}							    \n\
-									    \n\
-		static inline struct %1$s *				    \n\
-		%1$s__open_opts(struct bpf_embed_data *embed, const struct bpf_object_open_opts *opts)\n\
-		{							    \n\
-			struct %1$s *obj;				    \n\
-									    \n\
-			obj = calloc(1, sizeof(*obj));			    \n\
-			if (!obj)					    \n\
-				return NULL;				    \n\
-									    \n\
-			obj->skeleton = %1$s__create_skeleton(obj, embed);  \n\
-			if (!obj->skeleton)				    \n\
-				goto err;				    \n\
-									    \n\
-			if (bpf_object__open_skeleton(obj->skeleton, opts)) \n\
-				goto err;				    \n\
+			s->data_sz = %d;				    \n\
+			s->data = \"\\					    \n\
+		",
+		file_sz);
+
+	/* embed contents of BPF object file */
+	for (i = 0, len = 0; i < file_sz; i++) {
+		int w = obj_data[i] ? 4 : 2;
+
+		len += w;
+		if (len > 78) {
+			printf("\\\n");
+			len = w;
+		}
+		if (!obj_data[i])
+			printf("\\0");
+		else
+			printf("\\x%02x", (unsigned char)obj_data[i]);
+	}
+
+	codegen("\
+		\n\
+		\";							    \n\
 									    \n\
-			return obj;					    \n\
+			return 0;					    \n\
 		err:							    \n\
-			%1$s__destroy(obj);				    \n\
-			return NULL;					    \n\
-		}							    \n\
-									    \n\
-		static inline struct %1$s *				    \n\
-		%1$s__open(struct bpf_embed_data *embed)		    \n\
-		{							    \n\
-			return %1$s__open_opts(embed, NULL);		    \n\
-		}							    \n\
-									    \n\
-		static inline int					    \n\
-		%1$s__load(struct %1$s *obj)				    \n\
-		{							    \n\
-			return bpf_object__load_skeleton(obj->skeleton);    \n\
-		}							    \n\
-									    \n\
-		static inline struct %1$s *				    \n\
-		%1$s__open_and_load(struct bpf_embed_data *embed)	    \n\
-		{							    \n\
-			struct %1$s *obj;				    \n\
-									    \n\
-			obj = %1$s__open(embed);			    \n\
-			if (!obj)					    \n\
-				return NULL;				    \n\
-			if (%1$s__load(obj)) {				    \n\
-				%1$s__destroy(obj);			    \n\
-				return NULL;				    \n\
-			}						    \n\
-			return obj;					    \n\
-		}							    \n\
-									    \n\
-		static inline int					    \n\
-		%1$s__attach(struct %1$s *obj)				    \n\
-		{							    \n\
-			return bpf_object__attach_skeleton(obj->skeleton);  \n\
-		}							    \n\
-									    \n\
-		static inline void					    \n\
-		%1$s__detach(struct %1$s *obj)				    \n\
-		{							    \n\
-			return bpf_object__detach_skeleton(obj->skeleton);  \n\
+			bpf_object__destroy_skeleton(s);		    \n\
+			return -1;					    \n\
 		}							    \n\
 									    \n\
 		#endif /* %2$s */					    \n\
 		",
-		obj_name, header_guard
-	);
+		obj_name, header_guard);
 	err = 0;
 out:
 	bpf_object__close(obj);
+	if (obj_data)
+		munmap(obj_data, mmap_sz);
+	close(fd);
 	return err;
 }