bpf: libbpf: Fix bpf_program__next() API

This patch restores the behavior in
commit eac7d84519a3 ("tools: libbpf: don't return '.text' as a program for multi-function programs")
such that bpf_program__next() does not return pseudo programs in ".text".

Fixes: 0c19a9fbc9cd ("libbpf: cleanup after partial failure in bpf_object__pin")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 11 insertions, 14 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e827542ffa3a..a01eb9584e52 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2193,19 +2193,25 @@ void *bpf_object__priv(struct bpf_object *obj)
 }
 
 static struct bpf_program *
-__bpf_program__iter(struct bpf_program *p, struct bpf_object *obj, int i)
+__bpf_program__iter(struct bpf_program *p, struct bpf_object *obj, bool forward)
 {
+        size_t nr_programs = obj->nr_programs;
         ssize_t idx;
 
-        if (!obj->programs)
+        if (!nr_programs)
                 return NULL;
 
+        if (!p)
+                /* Iter from the beginning */
+                return forward ? &obj->programs[0] :
+                        &obj->programs[nr_programs - 1];
+
         if (p->obj != obj) {
                 pr_warning("error: program handler doesn't match object\n");
                 return NULL;
         }
 
-        idx = (p - obj->programs) + i;
+        idx = (p - obj->programs) + (forward ? 1 : -1);
         if (idx >= obj->nr_programs || idx < 0)
                 return NULL;
         return &obj->programs[idx];
@@ -2216,11 +2222,8 @@ bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
 {
         struct bpf_program *prog = prev;
 
-        if (prev == NULL)
-                return obj->programs;
-
         do {
-                prog = __bpf_program__iter(prog, obj, 1);
+                prog = __bpf_program__iter(prog, obj, true);
         } while (prog && bpf_program__is_function_storage(prog, obj));
 
         return prog;
@@ -2231,14 +2234,8 @@ bpf_program__prev(struct bpf_program *next, struct bpf_object *obj)
 {
         struct bpf_program *prog = next;
 
-        if (next == NULL) {
-                if (!obj->nr_programs)
-                        return NULL;
-                return obj->programs + obj->nr_programs - 1;
-        }
-
         do {
-                prog = __bpf_program__iter(prog, obj, -1);
+                prog = __bpf_program__iter(prog, obj, false);
         } while (prog && bpf_program__is_function_storage(prog, obj));
 
         return prog;