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authorMichal Rostecki <mrostecki@opensuse.org>2019-05-29 20:31:09 +0200
committerAlexei Starovoitov <ast@kernel.org>2019-05-31 17:03:39 -0700
commitcfd4921049269ee6765b4a1cb820b95d0df5dda5 (patch)
tree7c5a15cd500f3fd35f8357672f97fd0ab8b0e74e /tools/lib
parent5fac1718e706d94a7078addee9075cfaea00ca8c (diff)
libbpf: Return btf_fd for load_sk_storage_btf
Before this change, function load_sk_storage_btf expected that libbpf__probe_raw_btf was returning a BTF descriptor, but in fact it was returning an information about whether the probe was successful (0 or 1). load_sk_storage_btf was using that value as an argument of the close function, which was resulting in closing stdout and thus terminating the process which called that function. That bug was visible in bpftool. `bpftool feature` subcommand was always exiting too early (because of closed stdout) and it didn't display all requested probes. `bpftool -j feature` or `bpftool -p feature` were not returning a valid json object. This change renames the libbpf__probe_raw_btf function to libbpf__load_raw_btf, which now returns a BTF descriptor, as expected in load_sk_storage_btf. v2: - Fix typo in the commit message. v3: - Simplify BTF descriptor handling in bpf_object__probe_btf_* functions. - Rename libbpf__probe_raw_btf function to libbpf__load_raw_btf and return a BTF descriptor. v4: - Fix typo in the commit message. Fixes: d7c4b3980c18 ("libbpf: detect supported kernel BTF features and sanitize BTF") Signed-off-by: Michal Rostecki <mrostecki@opensuse.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.c28
-rw-r--r--tools/lib/bpf/libbpf_internal.h4
-rw-r--r--tools/lib/bpf/libbpf_probes.c13
3 files changed, 22 insertions, 23 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 197b574406b3..5d046cc7b207 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1645,14 +1645,16 @@ static int bpf_object__probe_btf_func(struct bpf_object *obj)
/* FUNC x */ /* [3] */
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
};
- int res;
+ int btf_fd;
- res = libbpf__probe_raw_btf((char *)types, sizeof(types),
- strs, sizeof(strs));
- if (res < 0)
- return res;
- if (res > 0)
+ btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
+ strs, sizeof(strs));
+ if (btf_fd >= 0) {
obj->caps.btf_func = 1;
+ close(btf_fd);
+ return 1;
+ }
+
return 0;
}
@@ -1670,14 +1672,16 @@ static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
BTF_VAR_SECINFO_ENC(2, 0, 4),
};
- int res;
+ int btf_fd;
- res = libbpf__probe_raw_btf((char *)types, sizeof(types),
- strs, sizeof(strs));
- if (res < 0)
- return res;
- if (res > 0)
+ btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
+ strs, sizeof(strs));
+ if (btf_fd >= 0) {
obj->caps.btf_datasec = 1;
+ close(btf_fd);
+ return 1;
+ }
+
return 0;
}
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index f3025b4d90e1..dfab8012185c 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -34,7 +34,7 @@ do { \
#define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
#define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
-int libbpf__probe_raw_btf(const char *raw_types, size_t types_len,
- const char *str_sec, size_t str_len);
+int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
+ const char *str_sec, size_t str_len);
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 5e2aa83f637a..6635a31a7a16 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -133,8 +133,8 @@ bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
return errno != EINVAL && errno != EOPNOTSUPP;
}
-int libbpf__probe_raw_btf(const char *raw_types, size_t types_len,
- const char *str_sec, size_t str_len)
+int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
+ const char *str_sec, size_t str_len)
{
struct btf_header hdr = {
.magic = BTF_MAGIC,
@@ -157,14 +157,9 @@ int libbpf__probe_raw_btf(const char *raw_types, size_t types_len,
memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false);
- if (btf_fd < 0) {
- free(raw_btf);
- return 0;
- }
- close(btf_fd);
free(raw_btf);
- return 1;
+ return btf_fd;
}
static int load_sk_storage_btf(void)
@@ -190,7 +185,7 @@ static int load_sk_storage_btf(void)
BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
};
- return libbpf__probe_raw_btf((char *)types, sizeof(types),
+ return libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs));
}