From a94364603610f341564351a0e130c4bbcaeddfa0 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 24 Oct 2019 15:30:25 +0200 Subject: [PATCH] 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 Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Acked-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/20191024133025.10691-1-jolsa@kernel.org --- tools/bpf/bpftool/btf.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-) 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 #include #include +#include +#include +#include #include "btf.h" #include "json_writer.h" @@ -388,6 +391,54 @@ done: 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; -- 2.7.4