[PATCH] bpftool: Try to read btf as raw data if elf read fails
From: Jiri Olsa <jolsa@kernel.org>
Date: 2019-10-18 10:34:08
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [tooling] (bpftool), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Quentin Monnet, Linus Torvalds
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 libbpf: failed to get EHDR from /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 I'm also adding err init to 0 because I was getting uninitialized warnings from gcc. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- tools/bpf/bpftool/btf.c | 47 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 42 insertions(+), 5 deletions(-)
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 9a9376d1d3df..100fb7e02329 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 +391,35 @@ static int dump_btf_c(const struct btf *btf, return err; } +static struct btf *btf__parse_raw(const char *file) +{ + struct btf *btf = ERR_PTR(-EINVAL); + __u8 *buf = NULL; + struct stat st; + FILE *f; + + if (stat(file, &st)) + return btf; + + f = fopen(file, "rb"); + if (!f) + return btf; + + buf = malloc(st.st_size); + if (!buf) + goto err; + + if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) + goto err; + + btf = btf__new(buf, st.st_size); + +err: + free(buf); + fclose(f); + return btf; +} + static int do_dump(int argc, char **argv) { struct btf *btf = NULL;
@@ -397,7 +429,7 @@ static int do_dump(int argc, char **argv) __u32 btf_id = -1; const char *src; int fd = -1; - int err; + int err = 0; if (!REQ_ARGS(2)) { usage();
@@ -468,10 +500,15 @@ static int do_dump(int argc, char **argv) btf = btf__parse_elf(*argv, NULL); if (IS_ERR(btf)) { err = PTR_ERR(btf); - btf = NULL; - p_err("failed to load BTF from %s: %s", - *argv, strerror(err)); - goto done; + if (err == -LIBBPF_ERRNO__FORMAT) + btf = btf__parse_raw(*argv); + if (IS_ERR(btf)) { + btf = NULL; + /* Display the original error value. */ + p_err("failed to load BTF from %s: %s", + *argv, strerror(err)); + goto done; + } } NEXT_ARG(); } else {
--
2.21.0