From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41248) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZDEj-00015C-P0 for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:08:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gZDB6-0000FI-4z for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:04:45 -0500 From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Tue, 18 Dec 2018 12:03:31 +0100 Message-Id: <20181218110333.22558-2-philmd@redhat.com> In-Reply-To: <20181218110333.22558-1-philmd@redhat.com> References: <20181218110333.22558-1-philmd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v2 1/3] hw/acpi: Replace strncpy() by strpadcpy(pad='\0') List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Ben Pye , Stefan Weil , Howard Spoelstra , "Michael S. Tsirkin" , Jeff Cody , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Thomas Huth , Liu Yuan , Igor Mammedov , Max Reitz , Kevin Wolf , Eric Blake , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , David Hildenbrand , David Gibson , Markus Armbruster , qemu-block@nongnu.org, =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , "Dr. David Alan Gilbert" , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , 1803872@bugs.launchpad.net, Juan Quintela , Paolo Bonzini From: Marc-Andr=C3=A9 Lureau GCC 8 added a -Wstringop-truncation warning: The -Wstringop-truncation warning added in GCC 8.0 via r254630 for bug 81117 is specifically intended to highlight likely unintended uses of the strncpy function that truncate the terminating NUL character from the source string. This new warning leads to compilation failures: CC hw/acpi/core.o In function 'acpi_table_install', inlined from 'acpi_table_add' at qemu= /hw/acpi/core.c:296:5: qemu/hw/acpi/core.c:184:9: error: 'strncpy' specified bound 4 equals de= stination size [-Werror=3Dstringop-truncation] strncpy(ext_hdr->sig, hdrs->sig, sizeof ext_hdr->sig); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ make: *** [qemu/rules.mak:69: hw/acpi/core.o] Error 1 The ACPI tables don't require the strings to be NUL-terminated, therefore strncpy is the right function to use here. We could add a #pragma GCC diagnostic ignored "-Wstringop-truncation" around, disable the warning globally using -Wno-stringop-truncation, but since QEMU provides the strpadcpy() which does the same purpose, simply use it to avoid the annoying warning. Signed-off-by: Marc-Andr=C3=A9 Lureau Reviewed-by: Eric Blake Reviewed-by: Philippe Mathieu-Daud=C3=A9 [PMD: reword commit subject and description] Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- hw/acpi/aml-build.c | 6 ++++-- hw/acpi/core.c | 13 +++++++------ 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c index 1e43cd736d..397833462a 100644 --- a/hw/acpi/aml-build.c +++ b/hw/acpi/aml-build.c @@ -24,6 +24,7 @@ #include "hw/acpi/aml-build.h" #include "qemu/bswap.h" #include "qemu/bitops.h" +#include "qemu/cutils.h" #include "sysemu/numa.h" =20 static GArray *build_alloc_array(void) @@ -1532,13 +1533,14 @@ build_header(BIOSLinker *linker, GArray *table_da= ta, h->revision =3D rev; =20 if (oem_id) { - strncpy((char *)h->oem_id, oem_id, sizeof h->oem_id); + strpadcpy((char *)h->oem_id, sizeof h->oem_id, oem_id, '\0'); } else { memcpy(h->oem_id, ACPI_BUILD_APPNAME6, 6); } =20 if (oem_table_id) { - strncpy((char *)h->oem_table_id, oem_table_id, sizeof(h->oem_tab= le_id)); + strpadcpy((char *)h->oem_table_id, sizeof(h->oem_table_id), + oem_table_id, '\0'); } else { memcpy(h->oem_table_id, ACPI_BUILD_APPNAME4, 4); memcpy(h->oem_table_id + 4, sig, 4); diff --git a/hw/acpi/core.c b/hw/acpi/core.c index aafdc61648..6e8f4e5713 100644 --- a/hw/acpi/core.c +++ b/hw/acpi/core.c @@ -31,6 +31,7 @@ #include "qapi/qapi-visit-misc.h" #include "qemu/error-report.h" #include "qemu/option.h" +#include "qemu/cutils.h" =20 struct acpi_table_header { uint16_t _length; /* our length, not actual part of the hdr = */ @@ -181,7 +182,7 @@ static void acpi_table_install(const char unsigned *b= lob, size_t bloblen, ext_hdr->_length =3D cpu_to_le16(acpi_payload_size); =20 if (hdrs->has_sig) { - strncpy(ext_hdr->sig, hdrs->sig, sizeof ext_hdr->sig); + strpadcpy(ext_hdr->sig, sizeof ext_hdr->sig, hdrs->sig, '\0'); ++changed_fields; } =20 @@ -200,12 +201,12 @@ static void acpi_table_install(const char unsigned = *blob, size_t bloblen, ext_hdr->checksum =3D 0; =20 if (hdrs->has_oem_id) { - strncpy(ext_hdr->oem_id, hdrs->oem_id, sizeof ext_hdr->oem_id); + strpadcpy(ext_hdr->oem_id, sizeof ext_hdr->oem_id, hdrs->oem_id,= '\0'); ++changed_fields; } if (hdrs->has_oem_table_id) { - strncpy(ext_hdr->oem_table_id, hdrs->oem_table_id, - sizeof ext_hdr->oem_table_id); + strpadcpy(ext_hdr->oem_table_id, sizeof ext_hdr->oem_table_id, + hdrs->oem_table_id, '\0'); ++changed_fields; } if (hdrs->has_oem_rev) { @@ -213,8 +214,8 @@ static void acpi_table_install(const char unsigned *b= lob, size_t bloblen, ++changed_fields; } if (hdrs->has_asl_compiler_id) { - strncpy(ext_hdr->asl_compiler_id, hdrs->asl_compiler_id, - sizeof ext_hdr->asl_compiler_id); + strpadcpy(ext_hdr->asl_compiler_id, sizeof ext_hdr->asl_compiler= _id, + hdrs->asl_compiler_id, '\0'); ++changed_fields; } if (hdrs->has_asl_compiler_rev) { --=20 2.17.2