libbpf: Replace '.' with '_' in legacy kprobe event name

'.' is not allowed in the event name of kprobe. Therefore, we will get a
EINVAL if the kernel function name has a '.' in legacy kprobe attach
case, such as 'icmp_reply.constprop.0'.

In order to adapt this case, we need to replace the '.' with other char
in gen_kprobe_legacy_event_name(). And I use '_' for this propose.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20230113093427.1666466-1-imagedong@tencent.com

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index f8dfee32c2bc563d90b67531668e33568740e5c2..27d9faa804713b830f837bcc9b6178f2e6e37b0b 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9994,9 +9994,16 @@ static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
                                         const char *kfunc_name, size_t offset)
 {
        static int index = 0;
+       int i;
 
        snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset,
                 __sync_fetch_and_add(&index, 1));
+
+       /* sanitize binary_path in the probe name */
+       for (i = 0; buf[i]; i++) {
+               if (!isalnum(buf[i]))
+                       buf[i] = '_';
+       }
 }
 
 static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,