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| author | Daniel Borkmann <daniel@iogearbox.net> | 2020-08-03 16:39:48 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-08-03 16:39:51 +0200 |
| commit | cfa3eb65a7d6da5664d4c9275fbb568a2446d6d9 (patch) | |
| tree | 6a78a898df8a336f40e0be88bc95bf1eaffea155 /tools/lib/bpf/btf.c | |
| parent | 041549b7b2c7811ec40e705c439211f00ade2dda (diff) | |
| parent | f86ca3cffef153555a3f4755b3a44881d962754f (diff) | |
| download | linux-cfa3eb65a7d6da5664d4c9275fbb568a2446d6d9.tar.gz linux-cfa3eb65a7d6da5664d4c9275fbb568a2446d6d9.tar.bz2 linux-cfa3eb65a7d6da5664d4c9275fbb568a2446d6d9.zip | |
Merge branch 'bpf-libbpf-btf-parsing'
Andrii Nakryiko says:
====================
It's pretty common for applications to want to parse raw (binary) BTF data
from file, as opposed to parsing it from ELF sections. It's also pretty common
for tools to not care whether given file is ELF or raw BTF format. This patch
series exposes internal raw BTF parsing API and adds generic variant of BTF
parsing, which will efficiently determine the format of a given fail and will
parse BTF appropriately.
Patches #2 and #3 removes re-implementations of such APIs from bpftool and
resolve_btfids tools.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools/lib/bpf/btf.c')
| -rw-r--r-- | tools/lib/bpf/btf.c | 114 |
1 files changed, 78 insertions, 36 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index ded5b29965f9..856b09a04563 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -562,6 +562,83 @@ done: return btf; } +struct btf *btf__parse_raw(const char *path) +{ + void *data = NULL; + struct btf *btf; + FILE *f = NULL; + __u16 magic; + int err = 0; + long sz; + + f = fopen(path, "rb"); + if (!f) { + err = -errno; + goto err_out; + } + + /* check BTF magic */ + if (fread(&magic, 1, sizeof(magic), f) < sizeof(magic)) { + err = -EIO; + goto err_out; + } + if (magic != BTF_MAGIC) { + /* definitely not a raw BTF */ + err = -EPROTO; + goto err_out; + } + + /* get file size */ + if (fseek(f, 0, SEEK_END)) { + err = -errno; + goto err_out; + } + sz = ftell(f); + if (sz < 0) { + err = -errno; + goto err_out; + } + /* rewind to the start */ + if (fseek(f, 0, SEEK_SET)) { + err = -errno; + goto err_out; + } + + /* pre-alloc memory and read all of BTF data */ + data = malloc(sz); + if (!data) { + err = -ENOMEM; + goto err_out; + } + if (fread(data, 1, sz, f) < sz) { + err = -EIO; + goto err_out; + } + + /* finally parse BTF data */ + btf = btf__new(data, sz); + +err_out: + free(data); + if (f) + fclose(f); + return err ? ERR_PTR(err) : btf; +} + +struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) +{ + struct btf *btf; + + if (btf_ext) + *btf_ext = NULL; + + btf = btf__parse_raw(path); + if (!IS_ERR(btf) || PTR_ERR(btf) != -EPROTO) + return btf; + + return btf__parse_elf(path, btf_ext); +} + static int compare_vsi_off(const void *_a, const void *_b) { const struct btf_var_secinfo *a = _a; @@ -2951,41 +3028,6 @@ static int btf_dedup_remap_types(struct btf_dedup *d) return 0; } -static struct btf *btf_load_raw(const char *path) -{ - struct btf *btf; - size_t read_cnt; - struct stat st; - void *data; - FILE *f; - - if (stat(path, &st)) - return ERR_PTR(-errno); - - data = malloc(st.st_size); - if (!data) - return ERR_PTR(-ENOMEM); - - f = fopen(path, "rb"); - if (!f) { - btf = ERR_PTR(-errno); - goto cleanup; - } - - read_cnt = fread(data, 1, st.st_size, f); - fclose(f); - if (read_cnt < st.st_size) { - btf = ERR_PTR(-EBADF); - goto cleanup; - } - - btf = btf__new(data, read_cnt); - -cleanup: - free(data); - return btf; -} - /* * Probe few well-known locations for vmlinux kernel image and try to load BTF * data out of it to use for target BTF. @@ -3021,7 +3063,7 @@ struct btf *libbpf_find_kernel_btf(void) continue; if (locations[i].raw_btf) - btf = btf_load_raw(path); + btf = btf__parse_raw(path); else btf = btf__parse_elf(path, NULL); |