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 <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

Author: anakryiko

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;
 }
 

tools/testing/selftests/bpf/prog_tests/attach_probe.c

@@ -22,8 +22,6 @@ ssize_t get_base_addr() {
 	return -EINVAL;
 }
 
-BPF_EMBED_OBJ(probe, "test_attach_probe.o");
-
 void test_attach_probe(void)
 {
 	int duration = 0;
@@ -39,7 +37,7 @@ void test_attach_probe(void)
 		return;
 	uprobe_offset = (size_t)&get_base_addr - base_addr;
 
-	skel = test_attach_probe__open_and_load(&probe_embed);
+	skel = test_attach_probe__open_and_load();
 	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
 		return;
 	if (CHECK(!skel->bss, "check_bss", ".bss wasn't mmap()-ed\n"))

tools/testing/selftests/bpf/prog_tests/core_extern.c

@@ -124,8 +124,6 @@ static struct test_case {
 	{ .name = "u64 (max+1)", .fails = 1, .cfg = CFG"CONFIG_ULONG=0x10000000000000000" },
 };
 
-BPF_EMBED_OBJ(core_extern, "test_core_extern.o");
-
 void test_core_extern(void)
 {
 	const uint32_t kern_ver = get_kernel_version();
@@ -159,7 +157,7 @@ void test_core_extern(void)
 			opts.kconfig_path = tmp_cfg_path;
 		}
 
-		skel = test_core_extern__open_opts(&core_extern_embed, &opts);
+		skel = test_core_extern__open_opts(&opts);
 		if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
 			goto cleanup;
 		err = test_core_extern__load(skel);

tools/testing/selftests/bpf/prog_tests/fentry_fexit.c

@@ -5,10 +5,6 @@
 #include "fentry_test.skel.h"
 #include "fexit_test.skel.h"
 
-BPF_EMBED_OBJ(pkt_access, "test_pkt_access.o");
-BPF_EMBED_OBJ(fentry, "fentry_test.o");
-BPF_EMBED_OBJ(fexit, "fexit_test.o");
-
 void test_fentry_fexit(void)
 {
 	struct test_pkt_access *pkt_skel = NULL;
@@ -18,13 +14,13 @@ void test_fentry_fexit(void)
 	__u32 duration = 0, retval;
 	int err, pkt_fd, i;
 
-	pkt_skel = test_pkt_access__open_and_load(&pkt_access_embed);
+	pkt_skel = test_pkt_access__open_and_load();
 	if (CHECK(!pkt_skel, "pkt_skel_load", "pkt_access skeleton failed\n"))
 		return;
-	fentry_skel = fentry_test__open_and_load(&fentry_embed);
+	fentry_skel = fentry_test__open_and_load();
 	if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))
 		goto close_prog;
-	fexit_skel = fexit_test__open_and_load(&fexit_embed);
+	fexit_skel = fexit_test__open_and_load();
 	if (CHECK(!fexit_skel, "fexit_skel_load", "fexit skeleton failed\n"))
 		goto close_prog;
 

tools/testing/selftests/bpf/prog_tests/fentry_test.c

@@ -4,9 +4,6 @@
 #include "test_pkt_access.skel.h"
 #include "fentry_test.skel.h"
 
-BPF_EMBED_OBJ_DECLARE(pkt_access);
-BPF_EMBED_OBJ_DECLARE(fentry);
-
 void test_fentry_test(void)
 {
 	struct test_pkt_access *pkt_skel = NULL;
@@ -15,10 +12,10 @@ void test_fentry_test(void)
 	__u32 duration, retval;
 	__u64 *result;
 
-	pkt_skel = test_pkt_access__open_and_load(&pkt_access_embed);
+	pkt_skel = test_pkt_access__open_and_load();
 	if (CHECK(!pkt_skel, "pkt_skel_load", "pkt_access skeleton failed\n"))
 		return;
-	fentry_skel = fentry_test__open_and_load(&fentry_embed);
+	fentry_skel = fentry_test__open_and_load();
 	if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))
 		goto cleanup;