* [PATCH] util/vfio-helpers: Use g_file_read_link()
@ 2023-05-22 11:49 Akihiko Odaki
2023-05-22 12:38 ` Philippe Mathieu-Daudé
2023-05-22 12:47 ` Cédric Le Goater
0 siblings, 2 replies; 4+ messages in thread
From: Akihiko Odaki @ 2023-05-22 11:49 UTC (permalink / raw)
Cc: qemu-devel, Alex Williamson, Cédric Le Goater, Akihiko Odaki
When _FORTIFY_SOURCE=2, glibc version is 2.35, and GCC version is
12.1.0, the compiler complains as follows:
In file included from /usr/include/features.h:490,
from /usr/include/bits/libc-header-start.h:33,
from /usr/include/stdint.h:26,
from /usr/lib/gcc/aarch64-unknown-linux-gnu/12.1.0/include/stdint.h:9,
from /home/alarm/q/var/qemu/include/qemu/osdep.h:94,
from ../util/vfio-helpers.c:13:
In function 'readlink',
inlined from 'sysfs_find_group_file' at ../util/vfio-helpers.c:116:9,
inlined from 'qemu_vfio_init_pci' at ../util/vfio-helpers.c:326:18,
inlined from 'qemu_vfio_open_pci' at ../util/vfio-helpers.c:517:9:
/usr/include/bits/unistd.h:119:10: error: argument 2 is null but the corresponding size argument 3 value is 4095 [-Werror=nonnull]
119 | return __glibc_fortify (readlink, __len, sizeof (char),
| ^~~~~~~~~~~~~~~
This error implies the allocated buffer can be NULL. Use
g_file_read_link(), which allocates buffer automatically to avoid the
error.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
util/vfio-helpers.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
index 2d8af38f88..e482ab22e2 100644
--- a/util/vfio-helpers.c
+++ b/util/vfio-helpers.c
@@ -106,15 +106,17 @@ struct QEMUVFIOState {
*/
static char *sysfs_find_group_file(const char *device, Error **errp)
{
+ g_autoptr(GError) gerr;
char *sysfs_link;
char *sysfs_group;
char *p;
char *path = NULL;
sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
- sysfs_group = g_malloc0(PATH_MAX);
- if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
- error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
+ sysfs_group = g_file_read_link(sysfs_link, &gerr);
+ if (gerr) {
+ error_setg(errp, "Failed to find iommu group sysfs path: %s",
+ gerr->message);
goto out;
}
p = strrchr(sysfs_group, '/');
--
2.40.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] util/vfio-helpers: Use g_file_read_link()
2023-05-22 11:49 [PATCH] util/vfio-helpers: Use g_file_read_link() Akihiko Odaki
@ 2023-05-22 12:38 ` Philippe Mathieu-Daudé
2023-05-22 12:44 ` Daniel P. Berrangé
2023-05-22 12:47 ` Cédric Le Goater
1 sibling, 1 reply; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2023-05-22 12:38 UTC (permalink / raw)
To: Akihiko Odaki; +Cc: qemu-devel, Alex Williamson, Cédric Le Goater
On 22/5/23 13:49, Akihiko Odaki wrote:
> When _FORTIFY_SOURCE=2, glibc version is 2.35, and GCC version is
> 12.1.0, the compiler complains as follows:
>
> In file included from /usr/include/features.h:490,
> from /usr/include/bits/libc-header-start.h:33,
> from /usr/include/stdint.h:26,
> from /usr/lib/gcc/aarch64-unknown-linux-gnu/12.1.0/include/stdint.h:9,
> from /home/alarm/q/var/qemu/include/qemu/osdep.h:94,
> from ../util/vfio-helpers.c:13:
> In function 'readlink',
> inlined from 'sysfs_find_group_file' at ../util/vfio-helpers.c:116:9,
> inlined from 'qemu_vfio_init_pci' at ../util/vfio-helpers.c:326:18,
> inlined from 'qemu_vfio_open_pci' at ../util/vfio-helpers.c:517:9:
> /usr/include/bits/unistd.h:119:10: error: argument 2 is null but the corresponding size argument 3 value is 4095 [-Werror=nonnull]
> 119 | return __glibc_fortify (readlink, __len, sizeof (char),
> | ^~~~~~~~~~~~~~~
>
> This error implies the allocated buffer can be NULL. Use
> g_file_read_link(), which allocates buffer automatically to avoid the
> error.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
> util/vfio-helpers.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
> index 2d8af38f88..e482ab22e2 100644
> --- a/util/vfio-helpers.c
> +++ b/util/vfio-helpers.c
> @@ -106,15 +106,17 @@ struct QEMUVFIOState {
> */
> static char *sysfs_find_group_file(const char *device, Error **errp)
> {
> + g_autoptr(GError) gerr;
Shouldn't this also be NULL-initialized (other picky compilers)?
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> char *sysfs_link;
> char *sysfs_group;
> char *p;
> char *path = NULL;
>
> sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
> - sysfs_group = g_malloc0(PATH_MAX);
> - if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
> - error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
> + sysfs_group = g_file_read_link(sysfs_link, &gerr);
> + if (gerr) {
> + error_setg(errp, "Failed to find iommu group sysfs path: %s",
> + gerr->message);
> goto out;
> }
> p = strrchr(sysfs_group, '/');
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] util/vfio-helpers: Use g_file_read_link()
2023-05-22 12:38 ` Philippe Mathieu-Daudé
@ 2023-05-22 12:44 ` Daniel P. Berrangé
0 siblings, 0 replies; 4+ messages in thread
From: Daniel P. Berrangé @ 2023-05-22 12:44 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: Akihiko Odaki, qemu-devel, Alex Williamson, Cédric Le Goater
On Mon, May 22, 2023 at 02:38:44PM +0200, Philippe Mathieu-Daudé wrote:
> On 22/5/23 13:49, Akihiko Odaki wrote:
> > When _FORTIFY_SOURCE=2, glibc version is 2.35, and GCC version is
> > 12.1.0, the compiler complains as follows:
> >
> > In file included from /usr/include/features.h:490,
> > from /usr/include/bits/libc-header-start.h:33,
> > from /usr/include/stdint.h:26,
> > from /usr/lib/gcc/aarch64-unknown-linux-gnu/12.1.0/include/stdint.h:9,
> > from /home/alarm/q/var/qemu/include/qemu/osdep.h:94,
> > from ../util/vfio-helpers.c:13:
> > In function 'readlink',
> > inlined from 'sysfs_find_group_file' at ../util/vfio-helpers.c:116:9,
> > inlined from 'qemu_vfio_init_pci' at ../util/vfio-helpers.c:326:18,
> > inlined from 'qemu_vfio_open_pci' at ../util/vfio-helpers.c:517:9:
> > /usr/include/bits/unistd.h:119:10: error: argument 2 is null but the corresponding size argument 3 value is 4095 [-Werror=nonnull]
> > 119 | return __glibc_fortify (readlink, __len, sizeof (char),
> > | ^~~~~~~~~~~~~~~
> >
> > This error implies the allocated buffer can be NULL. Use
> > g_file_read_link(), which allocates buffer automatically to avoid the
> > error.
> >
> > Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> > ---
> > util/vfio-helpers.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
> > index 2d8af38f88..e482ab22e2 100644
> > --- a/util/vfio-helpers.c
> > +++ b/util/vfio-helpers.c
> > @@ -106,15 +106,17 @@ struct QEMUVFIOState {
> > */
> > static char *sysfs_find_group_file(const char *device, Error **errp)
> > {
> > + g_autoptr(GError) gerr;
>
> Shouldn't this also be NULL-initialized (other picky compilers)?
Yes, *all* use of g_auto* must have an initializer at time of
declaration.
With regards,
Daniel
--
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] util/vfio-helpers: Use g_file_read_link()
2023-05-22 11:49 [PATCH] util/vfio-helpers: Use g_file_read_link() Akihiko Odaki
2023-05-22 12:38 ` Philippe Mathieu-Daudé
@ 2023-05-22 12:47 ` Cédric Le Goater
1 sibling, 0 replies; 4+ messages in thread
From: Cédric Le Goater @ 2023-05-22 12:47 UTC (permalink / raw)
To: Akihiko Odaki; +Cc: qemu-devel, Alex Williamson
Hello Akihiko,
On 5/22/23 13:49, Akihiko Odaki wrote:
> When _FORTIFY_SOURCE=2, glibc version is 2.35, and GCC version is
> 12.1.0, the compiler complains as follows:
>
> In file included from /usr/include/features.h:490,
> from /usr/include/bits/libc-header-start.h:33,
> from /usr/include/stdint.h:26,
> from /usr/lib/gcc/aarch64-unknown-linux-gnu/12.1.0/include/stdint.h:9,
> from /home/alarm/q/var/qemu/include/qemu/osdep.h:94,
> from ../util/vfio-helpers.c:13:
> In function 'readlink',
> inlined from 'sysfs_find_group_file' at ../util/vfio-helpers.c:116:9,
> inlined from 'qemu_vfio_init_pci' at ../util/vfio-helpers.c:326:18,
> inlined from 'qemu_vfio_open_pci' at ../util/vfio-helpers.c:517:9:
> /usr/include/bits/unistd.h:119:10: error: argument 2 is null but the corresponding size argument 3 value is 4095 [-Werror=nonnull]
> 119 | return __glibc_fortify (readlink, __len, sizeof (char),
> | ^~~~~~~~~~~~~~~
>
> This error implies the allocated buffer can be NULL. Use
> g_file_read_link(), which allocates buffer automatically to avoid the
> error.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
There are a few other VFIO routines computing the IOMMU group from sysfs :
vfio_ap_get_group()
vfio_ccw_get_group()
vfio_realize()
May be there is a possible common routine to introduce. Anyhow, this is
beyond the scope of this fix
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Thanks,
C.
> ---
> util/vfio-helpers.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
> index 2d8af38f88..e482ab22e2 100644
> --- a/util/vfio-helpers.c
> +++ b/util/vfio-helpers.c
> @@ -106,15 +106,17 @@ struct QEMUVFIOState {
> */
> static char *sysfs_find_group_file(const char *device, Error **errp)
> {
> + g_autoptr(GError) gerr;
> char *sysfs_link;
> char *sysfs_group;
> char *p;
> char *path = NULL;
>
> sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
> - sysfs_group = g_malloc0(PATH_MAX);
> - if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
> - error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
> + sysfs_group = g_file_read_link(sysfs_link, &gerr);
> + if (gerr) {
> + error_setg(errp, "Failed to find iommu group sysfs path: %s",
> + gerr->message);
> goto out;
> }
> p = strrchr(sysfs_group, '/');
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-05-22 11:49 [PATCH] util/vfio-helpers: Use g_file_read_link() Akihiko Odaki
2023-05-22 12:38 ` Philippe Mathieu-Daudé
2023-05-22 12:44 ` Daniel P. Berrangé
2023-05-22 12:47 ` Cédric Le Goater
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