| Message ID | 20181218110333.22558-2-philmd@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix strncpy() warnings for GCC8 new -Wstringop-truncation | expand |
On 12/18/18 12:03 PM, Philippe Mathieu-Daudé wrote: > From: Marc-André Lureau <marcandre.lureau@redhat.com> > > 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 destination size [-Werror=stringop-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-André Lureau <marcandre.lureau@redhat.com> > Reviewed-by: Eric Blake <eblake@redhat.com> > Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> > [PMD: reword commit subject and description] I forgot to also add "Use '\0' instead of 0". > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- v1: https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg03941.html > 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" > > static GArray *build_alloc_array(void) > @@ -1532,13 +1533,14 @@ build_header(BIOSLinker *linker, GArray *table_data, > h->revision = rev; > > 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); > } > > if (oem_table_id) { > - strncpy((char *)h->oem_table_id, oem_table_id, sizeof(h->oem_table_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" > > 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 *blob, size_t bloblen, > ext_hdr->_length = cpu_to_le16(acpi_payload_size); > > 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; > } > > @@ -200,12 +201,12 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen, > ext_hdr->checksum = 0; > > 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 *blob, 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) { >
On Tue, 18 Dec 2018 12:03:31 +0100 Philippe Mathieu-Daudé <philmd@redhat.com> wrote: > From: Marc-André Lureau <marcandre.lureau@redhat.com> > > 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 destination size [-Werror=stringop-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-André Lureau <marcandre.lureau@redhat.com> > Reviewed-by: Eric Blake <eblake@redhat.com> > Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> > [PMD: reword commit subject and description] > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Igor Mammedov <imammedo@redhat.com> > --- > 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" > > static GArray *build_alloc_array(void) > @@ -1532,13 +1533,14 @@ build_header(BIOSLinker *linker, GArray *table_data, > h->revision = rev; > > 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); > } > > if (oem_table_id) { > - strncpy((char *)h->oem_table_id, oem_table_id, sizeof(h->oem_table_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" > > 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 *blob, size_t bloblen, > ext_hdr->_length = cpu_to_le16(acpi_payload_size); > > 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; > } > > @@ -200,12 +201,12 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen, > ext_hdr->checksum = 0; > > 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 *blob, 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) {
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" static GArray *build_alloc_array(void) @@ -1532,13 +1533,14 @@ build_header(BIOSLinker *linker, GArray *table_data, h->revision = rev; 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); } if (oem_table_id) { - strncpy((char *)h->oem_table_id, oem_table_id, sizeof(h->oem_table_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" 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 *blob, size_t bloblen, ext_hdr->_length = cpu_to_le16(acpi_payload_size); 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; } @@ -200,12 +201,12 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen, ext_hdr->checksum = 0; 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 *blob, 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) {