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X-Received-From: 2607:f8b0:4864:20::841 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Eduardo Habkost , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When HAX is enabled (--enable-hax), GCC 9.2.1 reports issues with snprintf(). This commit is checking if snprintf returns an error. This is a simple way to avoid this warnings. An `assert()` boundary checks were added before snprintf too. For more details, one example of warning: CC i386-softmmu/target/i386/hax-posix.o qemu/target/i386/hax-posix.c: In function ‘hax_host_open_vm’: 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=] 124 | snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); | ^~~~ qemu/target/i386/hax-posix.c:124:41: note: directive argument in the range [-2147483648, 64] 124 | snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); | ^~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/stdio.h:867, from qemu/include/qemu/osdep.h:99, from 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 67 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 68 | __bos (__s), __fmt, __va_arg_pack ()); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Julio Faracco --- v1-v2: Add assert() as Richard Henderson suggested. v2-v3: Fix code syntax alignment with vm_id and snprintf() function. --- target/i386/hax-posix.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c index a5426a6dac..2151c9ed45 100644 --- a/target/i386/hax-posix.c +++ b/target/i386/hax-posix.c @@ -121,7 +121,12 @@ static char *hax_vm_devfs_string(int vm_id) return NULL; } - snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id); + assert(vm_id < 0); + + if (snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", + vm_id) < 0) + return NULL; + return name; } @@ -140,8 +145,12 @@ 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); + assert(vm_id < 0 || vcpu_id < 0); + + if (snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d", + vm_id, vcpu_id) < 0) + return NULL; + return name; } -- 2.24.1