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From: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>,
	"Song Liu" <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>
Cc: Benjamin Herrenschmidt <benh@amazon.com>,
	Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
	Kuniyuki Iwashima <kuni1840@gmail.com>, <bpf@vger.kernel.org>,
	<netdev@vger.kernel.org>
Subject: [PATCH v4 bpf-next 2/3] bpf: Support "%c" in bpf_bprintf_prepare().
Date: Tue, 10 Aug 2021 18:28:06 +0900	[thread overview]
Message-ID: <20210810092807.13190-3-kuniyu@amazon.co.jp> (raw)
In-Reply-To: <20210810092807.13190-1-kuniyu@amazon.co.jp>

/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>
---
 kernel/bpf/helpers.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 15746f779fe1..6d3aaf94e9ac 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -907,6 +907,20 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 			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;
 		}
 
-- 
2.30.2


  parent reply	other threads:[~2021-08-10  9:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-10  9:28 [PATCH v4 bpf-next 0/3] BPF iterator for UNIX domain socket Kuniyuki Iwashima
2021-08-10  9:28 ` [PATCH v4 bpf-next 1/3] bpf: af_unix: Implement " Kuniyuki Iwashima
2021-08-10 23:25   ` Yonghong Song
2021-08-10  9:28 ` Kuniyuki Iwashima [this message]
2021-08-10 23:32   ` [PATCH v4 bpf-next 2/3] bpf: Support "%c" in bpf_bprintf_prepare() Yonghong Song
2021-08-11 21:15   ` Andrii Nakryiko
2021-08-12  2:15     ` Kuniyuki Iwashima
2021-08-12  4:24       ` Andrii Nakryiko
2021-08-12  5:03         ` Kuniyuki Iwashima
2021-08-10  9:28 ` [PATCH v4 bpf-next 3/3] selftest/bpf: Implement sample UNIX domain socket iterator program Kuniyuki Iwashima
2021-08-10 23:46   ` Yonghong Song
2021-08-11  1:35     ` Kuniyuki Iwashima

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