bpftool: Allow to read btf as raw data
The bpftool interface stays the same, but now it's possible
to run it over BTF raw data, like:
$ bpftool btf dump file /sys/kernel/btf/vmlinux
[1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
[3] CONST '(anon)' type_id=2
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Link: https://lore.kernel.org/bpf/20191024133025.10691-1-jolsa@kernel.org
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 9a9376d..a7b8bf2 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -12,6 +12,9 @@
#include <libbpf.h>
#include <linux/btf.h>
#include <linux/hashtable.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
#include "btf.h"
#include "json_writer.h"
@@ -388,6 +391,54 @@ static int dump_btf_c(const struct btf *btf,
return err;
}
+static struct btf *btf__parse_raw(const char *file)
+{
+ struct btf *btf;
+ struct stat st;
+ __u8 *buf;
+ FILE *f;
+
+ if (stat(file, &st))
+ return NULL;
+
+ f = fopen(file, "rb");
+ if (!f)
+ return NULL;
+
+ buf = malloc(st.st_size);
+ if (!buf) {
+ btf = ERR_PTR(-ENOMEM);
+ goto exit_close;
+ }
+
+ if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) {
+ btf = ERR_PTR(-EINVAL);
+ goto exit_free;
+ }
+
+ btf = btf__new(buf, st.st_size);
+
+exit_free:
+ free(buf);
+exit_close:
+ fclose(f);
+ return btf;
+}
+
+static bool is_btf_raw(const char *file)
+{
+ __u16 magic = 0;
+ int fd;
+
+ fd = open(file, O_RDONLY);
+ if (fd < 0)
+ return false;
+
+ read(fd, &magic, sizeof(magic));
+ close(fd);
+ return magic == BTF_MAGIC;
+}
+
static int do_dump(int argc, char **argv)
{
struct btf *btf = NULL;
@@ -465,7 +516,11 @@ static int do_dump(int argc, char **argv)
}
NEXT_ARG();
} else if (is_prefix(src, "file")) {
- btf = btf__parse_elf(*argv, NULL);
+ if (is_btf_raw(*argv))
+ btf = btf__parse_raw(*argv);
+ else
+ btf = btf__parse_elf(*argv, NULL);
+
if (IS_ERR(btf)) {
err = PTR_ERR(btf);
btf = NULL;