[PATCH] bpftool: Allow to read btf as raw data
From: Jiri Olsa <jolsa@kernel.org>
Date: 2019-10-24 13:30:32
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 [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> --- v3 changes: - fix title v2 changes: - added is_btf_raw to find out which btf__parse_* function to call - changed labels and error propagation in btf__parse_raw - drop the err initialization, which is not needed under this change 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 9a9376d1d3df..a7b8bf233cf5 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;
--
2.21.0