From 3478cfcfcddff0f3aad82891be2992e51c4f7936 Mon Sep 17 00:00:00 2001
From: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Date: Sat, 14 Aug 2021 10:57:16 +0900
Subject: bpf: Support "%c" in bpf_bprintf_prepare().
/proc/net/unix uses "%c" to print a single-byte character to escape '\0' in
the name of the abstract UNIX domain socket. The following selftest uses
it, so this patch adds support for "%c". Note that it does not support
wide character ("%lc" and "%llc") for simplicity.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210814015718.42704-3-kuniyu@amazon.co.jp
---
kernel/bpf/helpers.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
(limited to 'kernel/bpf')
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 32761be48143..4e8540716187 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -907,6 +907,20 @@ fmt_str:
tmp_buf += err;
num_spec++;
+ continue;
+ } else if (fmt[i] == 'c') {
+ if (!tmp_buf)
+ goto nocopy_fmt;
+
+ if (tmp_buf_end == tmp_buf) {
+ err = -ENOSPC;
+ goto out;
+ }
+
+ *tmp_buf = raw_args[num_spec];
+ tmp_buf++;
+ num_spec++;
+
continue;
}
--
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