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=202510 header.b=k9i3K7Bs; dkim-atps=neutral Received: from mail.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id E3D0B5A0276 for ; Tue, 02 Dec 2025 04:20:36 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202510; t=1764645633; bh=Iha4PDbBlQnonrGHgLxqwHDJ9y5l0Xw/in6Iy4Os6R4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=k9i3K7BsAU5AvLCFXQCYE75fnLIilXpF5YTVVdS0S8QCr/ZIspLxefD34WUmOM1sd S4VHaCmXYykeA1Z68Yf0E+uGDDXigiJ6pqqmPEuTttIRlnsqHuuJtRjfaB5YEBLHqo vbmk58uADx7ifTKM0EKZljZOZ5gxPEfEjlrRMCXePFiUBdn5SF21UkaCcB4T5aU3H2 R/gdRE5ODgPEY1ZSCugVPqannqu569DCoJHcNcbY61pwrfnC0XG5pU0TSIbKOH+jxQ RH6iQ8GTy3id251h3gZ6wrNsvnhOs+6GBlqpDbjnRtabZI3F7Ox5Mk2SQl0HSt1HTj 4GmvOngm7xNyA== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4dL5cx6p0dz4wQH; Tue, 02 Dec 2025 14:20:33 +1100 (AEDT) Date: Tue, 2 Dec 2025 14:07:12 +1100 From: David Gibson To: Yumei Huang Subject: Re: [PATCH v10 2/5] util: Introduce read_file() and read_file_integer() function Message-ID: References: <20251202030007.23581-1-yuhuang@redhat.com> <20251202030007.23581-3-yuhuang@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="k6fPwwjhMnPjQpwn" Content-Disposition: inline In-Reply-To: <20251202030007.23581-3-yuhuang@redhat.com> Message-ID-Hash: 2IJSMAQZQBFKRBNKZBT4N2ONCBE4CFLI X-Message-ID-Hash: 2IJSMAQZQBFKRBNKZBT4N2ONCBE4CFLI 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: passt-dev@passt.top, sbrivio@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: --k6fPwwjhMnPjQpwn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Dec 02, 2025 at 11:00:04AM +0800, Yumei Huang wrote: > Signed-off-by: Yumei Huang Reviewed-by: David Gibson > --- > util.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > util.h | 1 + > 2 files changed, 92 insertions(+) >=20 > 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 =3D=3D 0 ? 0 : -1; > } > =20 > +/** > + * 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 failu= re > + */ > +static ssize_t read_file(const char *path, char *buf, size_t buf_size) > +{ > + size_t total_read =3D 0; > + int fd; > + > + if (!buf_size) > + return -EINVAL; > + > + fd =3D open(path, O_RDONLY | O_CLOEXEC); > + > + if (fd < 0) > + return -errno; > + > + while (total_read < buf_size) { > + ssize_t rc =3D read(fd, buf + total_read, buf_size - total_read); > + > + if (rc < 0) { > + int errno_save =3D errno; > + close(fd); > + return -errno_save; > + } > + > + if (rc =3D=3D 0) > + break; > + > + total_read +=3D rc; > + } > + > + close(fd); > + > + if (total_read =3D=3D buf_size) { > + buf[buf_size - 1] =3D '\0'; > + return -ENOBUFS; > + } > + > + buf[total_read] =3D '\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 =3D read_file(path, buf, sizeof(buf)); > + > + if (bytes_read < 0) > + goto error; > + > + if (bytes_read =3D=3D 0) { > + debug("Empty file %s", path); > + goto error; > + } > + > + errno =3D 0; > + value =3D strtoimax(buf, &end, 10); > + if (*end && *end !=3D '\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 __c= lone2(), > * 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); > --=20 > 2.51.1 >=20 --=20 David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson --k6fPwwjhMnPjQpwn Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmkuV9IACgkQzQJF27ox 2GfLjxAAg/mRZ1kB2qFb5NorEJfsglpUqjo/5Ag0saPYyU2v8WuXXIuKbq7NnEAF DZioOHiS7Z+Iv5StsknnAWE8pgufHc0pPZjT/fr7ZLYTbQ5qYVDrlaAcvTaZxkFt g8VqgfjXqUaJebe/aSxoVk7Qa5Z9JqtXYI1rtaYjIL6fYrbWfvtlYMwf8P6PWzo+ x6Pz0YgvGwPsCc849evsEmnkQwa2UWAN/yQ6P5symdxzeNGCpd703VRkwiBmdHTD VbHNNUItDAj16DTWpMK1jPp5LnljqeBOT5WVyViz062QNx9yTozGKy+G43dsYdkA HmDePobzNE8IGxr5jwz9kjS+EWEMx3DIBRlxmz4zEsOxZ/37fndpr0hsm+jClL/o 6czbGKTPGo9kELKObVrd1yC1dgbF3868WP39Ij2xfDoToNl4itparbz/Sptubamj ewtMVKAbuwpMGIv9hspZgjnl7XgAvJWNUjPGecEWM6pFgAWyN5XFbztZtAuy1Cdv qxBGDNR2n2SOrPraCnrrHW/amqk/LexhURT1M2ewu31JvjJ0rvkxf5wKiK94Yc9V lJyAlOIq+tap0b9Yei+TycAk89C8PpPwyoSQnfjCbFUSo9d2+5jkf05XNCyg50xb Y+XfRErK24v3l6IqA2cnCaJBhb9kaPO56Lcl7FFFkerl5OJ2ySI= =ZPJv -----END PGP SIGNATURE----- --k6fPwwjhMnPjQpwn--