From: Pan Nengyuan <pannengy...@huawei.com> Fix compile warnings: /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:124:56: error: ‘%02d’ directive output may be truncated writing between 2 and 11 bytes into a region of size 3 [-Werror=format-truncation=] snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); ^~~~ /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:124:41: note: directive argument in the range [-2147483648, 64] snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); ^~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/stdio.h:873, from /mnt/sdb/qemu-new/qemu_test/qemu/include/qemu/osdep.h:99, from /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:14: /usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output between 17 and 26 bytes into a destination of size 17 return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ __bos (__s), __fmt, __va_arg_pack ()); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c: In function ‘hax_vcpu_devfs_string’: /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:55: error: ‘%02d’ directive output may be truncated writing between 2 and 11 bytes into a region of size 10 [-Werror=format-truncation=] snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d", ^~~~ /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:43: note: directive argument in the range [-2147483648, 64] snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d", ^~~~~~~~~~~~~~~~~~~~~~~~~~ /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:43: note: directive argument in the range [-2147483648, 64] In file included from /usr/include/stdio.h:873, from /mnt/sdb/qemu-new/qemu_test/qemu/include/qemu/osdep.h:99, from /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:14: /usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output between 21 and 39 bytes into a destination of size 21 return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ __bos (__s), __fmt, __va_arg_pack ());
We know that we have checked the vm_id and vcpu_id in the first(less than 0x40), it will never be truncated in snprintf(). Thus, this patch add an assertion to clear this false-positive warning. Reported-by: Euler Robot <euler.ro...@huawei.com> Signed-off-by: Pan Nengyuan <pannengy...@huawei.com> --- target/i386/hax-posix.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c index a5426a6dac..197d5bc0f9 100644 --- a/target/i386/hax-posix.c +++ b/target/i386/hax-posix.c @@ -121,7 +121,8 @@ static char *hax_vm_devfs_string(int vm_id) return NULL; } - snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); + int len = snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); + assert(len < sizeof HAX_VM_DEVFS); return name; } @@ -140,8 +141,9 @@ static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id) return NULL; } - snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d", - vm_id, vcpu_id); + int len = snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d", + vm_id, vcpu_id); + assert(len < sizeof HAX_VCPU_DEVFS); return name; } -- 2.18.2