bpftool: Generalize light skeleton generation.

Generealize light skeleton by hiding mmap details in skel_internal.h
In this form generated lskel.h is usable both by user space and by the kernel.

Note that previously #include <bpf/bpf.h> was in *.lskel.h file.
To avoid #ifdef-s in a generated lskel.h the include of bpf.h is moved
to skel_internal.h, but skel_internal.h is also used by gen_loader.c
which is part of libbpf. Therefore skel_internal.h does #include "bpf.h"
in case of user space, so gen_loader.c and lskel.h have necessary definitions.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209232001.27490-4-alexei.starovoitov@gmail.com

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index eacfc6a2060d6413b9e7d61bfb150e1d4c7c0406..6f2e20be0c62fb6e821bbaa995367452cedbf31c 100644 (file)
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -472,7 +472,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
                        continue;
                if (bpf_map__is_internal(map) &&
                    (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
-                       printf("\tmunmap(skel->%1$s, %2$zd);\n",
+                       printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
                               ident, bpf_map_mmap_sz(map));
                codegen("\
                        \n\
@@ -481,7 +481,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
        }
        codegen("\
                \n\
-                       free(skel);                                         \n\
+                       skel_free(skel);                                    \n\
                }                                                           \n\
                ",
                obj_name);
@@ -525,7 +525,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
                {                                                           \n\
                        struct %1$s *skel;                                  \n\
                                                                            \n\
-                       skel = calloc(sizeof(*skel), 1);                    \n\
+                       skel = skel_alloc(sizeof(*skel));                   \n\
                        if (!skel)                                          \n\
                                goto cleanup;                               \n\
                        skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
@@ -543,19 +543,18 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
                        continue;
 
                codegen("\
-                       \n\
-                               skel->%1$s =                                     \n\
-                                       mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
-                                            MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
-                               if (skel->%1$s == (void *) -1)                   \n\
-                                       goto cleanup;                            \n\
-                               memcpy(skel->%1$s, (void *)\"\\                  \n\
-                       ", ident, bpf_map_mmap_sz(map));
+               \n\
+                       skel->%1$s = skel_prep_map_data((void *)\"\\        \n\
+               ", ident);
                mmap_data = bpf_map__initial_value(map, &mmap_size);
                print_hex(mmap_data, mmap_size);
-               printf("\", %2$zd);\n"
-                      "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
-                      ident, mmap_size);
+               codegen("\
+               \n\
+               \", %1$zd, %2$zd);                                          \n\
+                       if (!skel->%3$s)                                    \n\
+                               goto cleanup;                               \n\
+                       skel->maps.%3$s.initial_value = (__u64) (long) skel->%3$s;\n\
+               ", bpf_map_mmap_sz(map), mmap_size, ident);
        }
        codegen("\
                \n\
@@ -611,9 +610,13 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
                else
                        mmap_flags = "PROT_READ | PROT_WRITE";
 
-               printf("\tskel->%1$s =\n"
-                      "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
-                      "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
+               codegen("\
+               \n\
+                       skel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value,  \n\
+                                                       %2$zd, %3$s, skel->maps.%1$s.map_fd);\n\
+                       if (!skel->%1$s)                                    \n\
+                               return -ENOMEM;                             \n\
+                       ",
                       ident, bpf_map_mmap_sz(map), mmap_flags);
        }
        codegen("\
@@ -751,8 +754,6 @@ static int do_skeleton(int argc, char **argv)
                #ifndef %2$s                                                \n\
                #define %2$s                                                \n\
                                                                            \n\
-               #include <stdlib.h>                                         \n\
-               #include <bpf/bpf.h>                                        \n\
                #include <bpf/skel_internal.h>                              \n\
                                                                            \n\
                struct %1$s {                                               \n\