From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202408 header.b=ZwNrEFp9; dkim-atps=neutral Received: from mail.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id 18E3A5A004E for ; Wed, 18 Sep 2024 12:44:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202408; t=1726656248; bh=Ew6W4+SfXYSJPEt69yhcoRbYrl5vl9EXysTw2h5MKAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZwNrEFp9XXgM+pnA7xfRvZwmI398LX1znASZDrRt2uFGiOVrNZpHOQotM7EwQENT+ 25T5Ju6BfGHyqyvfed0klNISThqXvOZcz2b7JW3nyCCaC8L00WZq20d1qIzHbdOCzQ FyXyK0VyQUrqJOJXKYo64SFPsWtViiLe+fBPLFRp7QghBYGnugWOZz5ccQyQiTGq3G pIdkrNLyJZ/cEcPs0K2nr0wq/fL6mb4HTG9kXxade4Odq+1KTQIbwhN+uRcNlqG1uj 5BSyG86QsQn7zWjrdRRGFTXMcWccweu8Q7hGJKI5EuNtJ7HaYka9aE6RfTgW1ZLAdz NXJYVk8FUtCdA== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4X7wHr5LRYz4x2g; Wed, 18 Sep 2024 20:44:08 +1000 (AEST) From: David Gibson To: passt-dev@passt.top, Stefano Brivio Subject: [PATCH v3 1/2] util: Add helper to write() all of a buffer Date: Wed, 18 Sep 2024 20:44:05 +1000 Message-ID: <20240918104406.3050878-2-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240918104406.3050878-1-david@gibson.dropbear.id.au> References: <20240918104406.3050878-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: ESKR7O7CLLT7QQQYW2REQHAFBC45UF5U X-Message-ID-Hash: ESKR7O7CLLT7QQQYW2REQHAFBC45UF5U X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Markus Armbruster , David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: write(2) might not write all the data it is given. Add a write_all_buf() helper to keep calling it until all the given data is written, or we get an error. Currently we use write_remainder() to do this operation in pcap_frame(). That's a little awkward since it requires constructing an iovec, and future changes we want to make to write_remainder() will be easier in terms of this single buffer helper. Signed-off-by: David Gibson --- pcap.c | 3 +-- util.c | 25 +++++++++++++++++++++++++ util.h | 1 + 3 files changed, 27 insertions(+), 2 deletions(-) diff --git a/pcap.c b/pcap.c index 46cc4b0d..e6b5ced4 100644 --- a/pcap.c +++ b/pcap.c @@ -86,9 +86,8 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt, .caplen = l2len, .len = l2len }; - struct iovec hiov = { &h, sizeof(h) }; - if (write_remainder(pcap_fd, &hiov, 1, 0) < 0 || + if (write_all_buf(pcap_fd, &h, sizeof(h)) < 0 || write_remainder(pcap_fd, iov, iovcnt, offset) < 0) debug_perror("Cannot log packet, length %zu", l2len); } diff --git a/util.c b/util.c index eede4e58..7db7c2e7 100644 --- a/util.c +++ b/util.c @@ -582,6 +582,31 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags, #endif } +/* write_all_buf() - write all of a buffer to an fd + * @fd: File descriptor + * @buf: Pointer to base of buffer + * @len: Length of buffer + * + * Return: 0 on success, -1 on error (with errno set) + * + * #syscalls write + */ +int write_all_buf(int fd, const void *buf, size_t len) +{ + const char *p = buf; + size_t left = len; + + while (left) { + ssize_t rc = write(fd, p, left); + + if (rc < 0) + return -1; + p += rc; + left -= rc; + } + return 0; +} + /* write_remainder() - write the tail of an IO vector to an fd * @fd: File descriptor * @iov: IO vector diff --git a/util.h b/util.h index c7a59d5d..5e67f1fa 100644 --- a/util.h +++ b/util.h @@ -200,6 +200,7 @@ void pidfile_write(int fd, pid_t pid); int __daemon(int pidfile_fd, int devnull_fd); int fls(unsigned long x); int write_file(const char *path, const char *buf); +int write_all_buf(int fd, const void *buf, size_t len); int write_remainder(int fd, const struct iovec *iov, size_t iovcnt, size_t skip); void close_open_files(int argc, char **argv); -- 2.46.0