From fb2d40cc84f689e46138a81c57ccd1f234dbbb7c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Date: Wed, 12 Jul 2023 17:46:57 +0200 Subject: [PATCH 07/37] util/vfio-helpers: Use g_file_read_link() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Cédric Le Goater RH-MergeRequest: 179: vfio: live migration support RH-Bugzilla: 2192818 RH-Acked-by: Eric Auger RH-Acked-by: Miroslav Rezanina RH-Commit: [5/28] 3545a07c967782dba8dd081415232f91d3f600a9 (clegoate/qemu-kvm-c9s) Bugzilla: https://bugzilla.redhat.com/2192818 commit dbdea0dbfe2c Author: Akihiko Odaki Date: Tue May 23 11:39:12 2023 +0900 util/vfio-helpers: Use g_file_read_link() 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 Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Cédric Le Goater Signed-off-by: Cédric Le Goater Signed-off-by: Cédric Le Goater --- 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..f8bab46c68 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 = NULL; 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, '/'); -- 2.39.3