mirror/libbpf
1
0
Fork 0
mirror of https://github.com/netdata/libbpf.git synced 2026-03-29 12:49:07 +08:00
Code Issues Packages Projects Releases Wiki Activity

libbpf: Streamline bpf_attr and perf_event_attr initialization

Browse Source 
Make sure that entire libbpf code base is initializing bpf_attr and
perf_event_attr with memset(0). Also for bpf_attr make sure we
clear and pass to kernel only relevant parts of bpf_attr. bpf_attr is
a huge union of independent sub-command attributes, so there is no need
to clear and pass entire union bpf_attr, which over time grows quite
a lot and for most commands this growth is completely irrelevant.

Few cases where we were relying on compiler initialization of BPF UAPI
structs (like bpf_prog_info, bpf_map_info, etc) with `= {};` were
switched to memset(0) pattern for future-proofing.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20220816001929.369487-3-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
2022-08-15 17:19:27 -07:00
committed by Andrii Nakryiko
parent 06c4624c8c
commit f7cee4152f
4 changed files with 138 additions and 91 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
src/libbpf.c
View File

@@ -4287,11 +4287,12 @@ int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate)
int bpf_map__reuse_fd(struct bpf_map *map, int fd)
{
struct bpf_map_info info = {};
struct bpf_map_info info;
__u32 len = sizeof(info), name_len;
int new_fd, err;
char *new_name;
memset(&info, 0, len);
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err && errno == EINVAL)
err = bpf_get_map_info_from_fdinfo(fd, &info);
@@ -4833,13 +4834,12 @@ bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
{
struct bpf_map_info map_info = {};
struct bpf_map_info map_info;
char msg[STRERR_BUFSIZE];
__u32 map_info_len;
__u32 map_info_len = sizeof(map_info);
int err;
map_info_len = sizeof(map_info);
memset(&map_info, 0, map_info_len);
err = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len);
if (err && errno == EINVAL)
err = bpf_get_map_info_from_fdinfo(map_fd, &map_info);
@@ -9007,11 +9007,12 @@ int libbpf_find_vmlinux_btf_id(const char *name,
static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
{
struct bpf_prog_info info = {};
struct bpf_prog_info info;
__u32 info_len = sizeof(info);
struct btf *btf;
int err;
memset(&info, 0, info_len);
err = bpf_obj_get_info_by_fd(attach_prog_fd, &info, &info_len);
if (err) {
pr_warn("failed bpf_obj_get_info_by_fd for FD %d: %d\n",
@@ -9839,13 +9840,16 @@ static int determine_uprobe_retprobe_bit(void)
static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
uint64_t offset, int pid, size_t ref_ctr_off)
{
struct perf_event_attr attr = {};
const size_t attr_sz = sizeof(struct perf_event_attr);
struct perf_event_attr attr;
char errmsg[STRERR_BUFSIZE];
int type, pfd;
if (ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS))
return -EINVAL;
memset(&attr, 0, attr_sz);
type = uprobe ? determine_uprobe_perf_type()
: determine_kprobe_perf_type();
if (type < 0) {
@@ -9866,7 +9870,7 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
}
attr.config |= 1 << bit;
}
attr.size = sizeof(attr);
attr.size = attr_sz;
attr.type = type;
attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
@@ -9965,7 +9969,8 @@ static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retpro
static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
const char *kfunc_name, size_t offset, int pid)
{
struct perf_event_attr attr = {};
const size_t attr_sz = sizeof(struct perf_event_attr);
struct perf_event_attr attr;
char errmsg[STRERR_BUFSIZE];
int type, pfd, err;
@@ -9984,7 +9989,9 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
goto err_clean_legacy;
}
attr.size = sizeof(attr);
memset(&attr, 0, attr_sz);
attr.size = attr_sz;
attr.config = type;
attr.type = PERF_TYPE_TRACEPOINT;
@@ -10441,6 +10448,7 @@ static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retpro
static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe,
const char *binary_path, size_t offset, int pid)
{
const size_t attr_sz = sizeof(struct perf_event_attr);
struct perf_event_attr attr;
int type, pfd, err;
@@ -10458,8 +10466,8 @@ static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe,
goto err_clean_legacy;
}
memset(&attr, 0, sizeof(attr));
attr.size = sizeof(attr);
memset(&attr, 0, attr_sz);
attr.size = attr_sz;
attr.config = type;
attr.type = PERF_TYPE_TRACEPOINT;
@@ -10998,7 +11006,8 @@ static int determine_tracepoint_id(const char *tp_category,
static int perf_event_open_tracepoint(const char *tp_category,
const char *tp_name)
{
struct perf_event_attr attr = {};
const size_t attr_sz = sizeof(struct perf_event_attr);
struct perf_event_attr attr;
char errmsg[STRERR_BUFSIZE];
int tp_id, pfd, err;
@@ -11010,8 +11019,9 @@ static int perf_event_open_tracepoint(const char *tp_category,
return tp_id;
}
memset(&attr, 0, attr_sz);
attr.type = PERF_TYPE_TRACEPOINT;
attr.size = sizeof(attr);
attr.size = attr_sz;
attr.config = tp_id;
pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
@@ -11631,12 +11641,15 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
void *ctx,
const struct perf_buffer_opts *opts)
{
const size_t attr_sz = sizeof(struct perf_event_attr);
struct perf_buffer_params p = {};
struct perf_event_attr attr = {};
struct perf_event_attr attr;
if (!OPTS_VALID(opts, perf_buffer_opts))
return libbpf_err_ptr(-EINVAL);
memset(&attr, 0, attr_sz);
attr.size = attr_sz;
attr.config = PERF_COUNT_SW_BPF_OUTPUT;
attr.type = PERF_TYPE_SOFTWARE;
attr.sample_type = PERF_SAMPLE_RAW;