With the previous commit adding common attribute support for BPF_MAP_CREATE, it is now possible to retrieve detailed error messages when map creation fails by using the 'log_buf' field from the common attributes.
Introduce a new struct bpf_syscall_common_attr_opts, which wraps these new fields, 'log_buf', 'log_size', 'log_level', and 'log_true_size'.
Extend 'bpf_map_create_opts' with a new field, 'cattr_opts', allowing users to capture and inspect those log messages.
Signed-off-by: Leon Hwang leon.hwang@linux.dev --- tools/lib/bpf/bpf.c | 15 ++++++++++++++- tools/lib/bpf/bpf.h | 17 ++++++++++++++++- 2 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 689ade4a822b..4a1ba4951785 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -207,6 +207,9 @@ int bpf_map_create(enum bpf_map_type map_type, const struct bpf_map_create_opts *opts) { const size_t attr_sz = offsetofend(union bpf_attr, excl_prog_hash_size); + const size_t common_attrs_sz = sizeof(struct bpf_common_attr); + struct bpf_syscall_common_attr_opts *cattr_opts; + struct bpf_common_attr common_attrs; union bpf_attr attr; int fd;
@@ -240,7 +243,17 @@ int bpf_map_create(enum bpf_map_type map_type, attr.excl_prog_hash = ptr_to_u64(OPTS_GET(opts, excl_prog_hash, NULL)); attr.excl_prog_hash_size = OPTS_GET(opts, excl_prog_hash_size, 0);
- fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz); + cattr_opts = OPTS_GET(opts, cattr_opts, NULL); + if (cattr_opts && feat_supported(NULL, FEAT_EXTENDED_SYSCALL)) { + memset(&common_attrs, 0, common_attrs_sz); + common_attrs.log_buf = ptr_to_u64(OPTS_GET(cattr_opts, log_buf, NULL)); + common_attrs.log_size = OPTS_GET(cattr_opts, log_size, 0); + common_attrs.log_level = OPTS_GET(cattr_opts, log_level, 0); + fd = sys_bpf_ext_fd(BPF_MAP_CREATE, &attr, attr_sz, &common_attrs, common_attrs_sz); + OPTS_SET(cattr_opts, log_true_size, common_attrs.log_true_size); + } else { + fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz); + } return libbpf_err_errno(fd); }
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 1f9c28d27795..6f544c205b89 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -37,6 +37,18 @@ extern "C" {
LIBBPF_API int libbpf_set_memlock_rlim(size_t memlock_bytes);
+struct bpf_syscall_common_attr_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + + const char *log_buf; + __u32 log_size; + __u32 log_level; + __u32 log_true_size; + + size_t :0; +}; +#define bpf_syscall_common_attr_opts__last_field log_true_size + struct bpf_map_create_opts { size_t sz; /* size of this struct for forward/backward compatibility */
@@ -57,9 +69,12 @@ struct bpf_map_create_opts {
const void *excl_prog_hash; __u32 excl_prog_hash_size; + + struct bpf_syscall_common_attr_opts *cattr_opts; + size_t :0; }; -#define bpf_map_create_opts__last_field excl_prog_hash_size +#define bpf_map_create_opts__last_field cattr_opts
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type, const char *map_name,