diff mbox series

[bpf-next,v2] libbpf: fix probe code to return EPERM if encountered

Message ID 158858309381.5053.12391080967642755711.stgit@ebuild
State New
Headers show
Series [bpf-next,v2] libbpf: fix probe code to return EPERM if encountered | expand

Commit Message

Eelco Chaudron May 4, 2020, 9:05 a.m. UTC 
When the probe code was failing for any reason ENOTSUP was returned, even
if this was due to no having enough lock space. This patch fixes this by
returning EPERM to the user application, so it can respond and increase
the RLIMIT_MEMLOCK size.

Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
---
v2: Split bpf_object__probe_name() in two functions as suggested by Andrii

 tools/lib/bpf/libbpf.c |   25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8f480e29a6b0..6838e6d431ce 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3149,7 +3149,7 @@  int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
 }
 
 static int
-bpf_object__probe_name(struct bpf_object *obj)
+bpf_object__probe_loading(struct bpf_object *obj)
 {
 	struct bpf_load_program_attr attr;
 	char *cp, errmsg[STRERR_BUFSIZE];
@@ -3176,8 +3176,26 @@  bpf_object__probe_name(struct bpf_object *obj)
 	}
 	close(ret);
 
-	/* now try the same program, but with the name */
+	return 0;
+}
 
+static int
+bpf_object__probe_name(struct bpf_object *obj)
+{
+	struct bpf_load_program_attr attr;
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	int ret;
+
+	/* make sure loading with name works */
+
+	memset(&attr, 0, sizeof(attr));
+	attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
+	attr.insns = insns;
+	attr.insns_cnt = ARRAY_SIZE(insns);
+	attr.license = "GPL";
 	attr.name = "test";
 	ret = bpf_load_program_xattr(&attr, NULL, 0);
 	if (ret >= 0) {
@@ -5386,7 +5404,8 @@  int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
 
 	obj->loaded = true;
 
-	err = bpf_object__probe_caps(obj);
+	err = bpf_object__probe_loading(obj);
+	err = err ? : bpf_object__probe_caps(obj);
 	err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
 	err = err ? : bpf_object__sanitize_and_load_btf(obj);
 	err = err ? : bpf_object__sanitize_maps(obj);