From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=YOmLCyTt; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTPS id 6E5FE5A0276 for ; Tue, 02 Dec 2025 04:00:28 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764644427; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sLUnygPLQ1KvqIZP8YDqBgS8lYerp73AmD+ts59ud5Q=; b=YOmLCyTtNcKKPqOb4OY+bD/erVGxl+RMZ9yBokinAzqb/N2MRu5jCOAxsXvNsP987say6T KCacysFyVwqh+9LJpiLltZnly5TZ76lFDjIDQiQDFS9LgFnK3+f9mH7V1aGGzwsVTVTnBq Q82C19Qz83ZXZypGuMOmodFkEPHXaBU= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-250-QXuF0hQ-NACgGlGk3JE7BQ-1; Mon, 01 Dec 2025 22:00:24 -0500 X-MC-Unique: QXuF0hQ-NACgGlGk3JE7BQ-1 X-Mimecast-MFC-AGG-ID: QXuF0hQ-NACgGlGk3JE7BQ_1764644423 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DBE4C195609E; Tue, 2 Dec 2025 03:00:22 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.72.116.175]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1B149195608E; Tue, 2 Dec 2025 03:00:19 +0000 (UTC) From: Yumei Huang To: passt-dev@passt.top, sbrivio@redhat.com Subject: [PATCH v10 2/5] util: Introduce read_file() and read_file_integer() function Date: Tue, 2 Dec 2025 11:00:04 +0800 Message-ID: <20251202030007.23581-3-yuhuang@redhat.com> In-Reply-To: <20251202030007.23581-1-yuhuang@redhat.com> References: <20251202030007.23581-1-yuhuang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: MrP1gx4w-wFd1VP2DYAlKxIkZ584_kJ3XqJXn65de8w_1764644423 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: DR26O3YGXLSMJOCWOKXDVOPB6XAW5JFE X-Message-ID-Hash: DR26O3YGXLSMJOCWOKXDVOPB6XAW5JFE X-MailFrom: yuhuang@redhat.com 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: david@gibson.dropbear.id.au, yuhuang@redhat.com 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: Signed-off-by: Yumei Huang --- util.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ util.h | 1 + 2 files changed, 92 insertions(+) diff --git a/util.c b/util.c index ab23463..4fdb611 100644 --- a/util.c +++ b/util.c @@ -589,6 +589,97 @@ int write_file(const char *path, const char *buf) return len == 0 ? 0 : -1; } +/** + * read_file() - Read contents of file into a NULL-terminated buffer + * @path: Path to file to read + * @buf: Buffer to store file contents + * @buf_size: Size of buffer + * + * Return: number of bytes read on success, negative error code on failure + */ +static ssize_t read_file(const char *path, char *buf, size_t buf_size) +{ + size_t total_read = 0; + int fd; + + if (!buf_size) + return -EINVAL; + + fd = open(path, O_RDONLY | O_CLOEXEC); + + if (fd < 0) + return -errno; + + while (total_read < buf_size) { + ssize_t rc = read(fd, buf + total_read, buf_size - total_read); + + if (rc < 0) { + int errno_save = errno; + close(fd); + return -errno_save; + } + + if (rc == 0) + break; + + total_read += rc; + } + + close(fd); + + if (total_read == buf_size) { + buf[buf_size - 1] = '\0'; + return -ENOBUFS; + } + + buf[total_read] = '\0'; + + return total_read; +} + +/** + * read_file_integer() - Read an integer value from a file + * @path: Path to file to read + * @fallback: Default value if file can't be read + * + * Return: integer value, @fallback on failure + */ +intmax_t read_file_integer(const char *path, intmax_t fallback) +{ + ssize_t bytes_read; + char buf[BUFSIZ]; + intmax_t value; + char *end; + + bytes_read = read_file(path, buf, sizeof(buf)); + + if (bytes_read < 0) + goto error; + + if (bytes_read == 0) { + debug("Empty file %s", path); + goto error; + } + + errno = 0; + value = strtoimax(buf, &end, 10); + if (*end && *end != '\n') { + debug("Non-numeric content in %s", path); + goto error; + } + if (errno) { + debug("Out of range value in %s: %s", path, buf); + goto error; + } + + return value; + +error: + debug("Couldn't read %s, using %"PRIdMAX" as default value", + path, fallback); + return fallback; +} + #ifdef __ia64__ /* Needed by do_clone() below: glibc doesn't export the prototype of __clone2(), * use the description from clone(2). diff --git a/util.h b/util.h index a0b2ada..6dec14b 100644 --- a/util.h +++ b/util.h @@ -229,6 +229,7 @@ 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); +intmax_t read_file_integer(const char *path, intmax_t fallback); 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); int read_all_buf(int fd, void *buf, size_t len); -- 2.51.1