| Message ID | 20210505211047.1496765-4-philmd@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | misc: Remove variable-length arrays on the stack | expand |
Philippe Mathieu-Daudé, le mer. 05 mai 2021 23:10:27 +0200, a ecrit: > We know 'x * y' will be at most 'X_MAX * Y_MAX' (which is not > a big value, it is actually 84). Instead of having the compiler > use variable-length array, declare an array able to hold the > maximum 'x * y'. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> > --- > chardev/baum.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/chardev/baum.c b/chardev/baum.c > index adc3d7b3b56..0822e9ed5f3 100644 > --- a/chardev/baum.c > +++ b/chardev/baum.c > @@ -383,9 +383,9 @@ static int baum_eat_packet(BaumChardev *baum, const uint8_t *buf, int len) > switch (req) { > case BAUM_REQ_DisplayData: > { > - uint8_t cells[baum->x * baum->y], c; > - uint8_t text[baum->x * baum->y]; > - uint8_t zero[baum->x * baum->y]; > + uint8_t cells[X_MAX * Y_MAX], c; > + uint8_t text[X_MAX * Y_MAX]; > + uint8_t zero[X_MAX * Y_MAX]; > int cursor = BRLAPI_CURSOR_OFF; > int i; > > @@ -408,7 +408,7 @@ static int baum_eat_packet(BaumChardev *baum, const uint8_t *buf, int len) > } > timer_del(baum->cellCount_timer); > > - memset(zero, 0, sizeof(zero)); > + memset(zero, 0, baum->x * baum->y); > > brlapi_writeArguments_t wa = { > .displayNumber = BRLAPI_DISPLAY_DEFAULT, > -- > 2.26.3 >
On Thu, May 6, 2021 at 1:14 AM Philippe Mathieu-Daudé <philmd@redhat.com> wrote: > We know 'x * y' will be at most 'X_MAX * Y_MAX' (which is not > a big value, it is actually 84). Instead of having the compiler > use variable-length array, declare an array able to hold the > maximum 'x * y'. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- > chardev/baum.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/chardev/baum.c b/chardev/baum.c > index adc3d7b3b56..0822e9ed5f3 100644 > --- a/chardev/baum.c > +++ b/chardev/baum.c > @@ -383,9 +383,9 @@ static int baum_eat_packet(BaumChardev *baum, const > uint8_t *buf, int len) > switch (req) { > case BAUM_REQ_DisplayData: > { > - uint8_t cells[baum->x * baum->y], c; > - uint8_t text[baum->x * baum->y]; > - uint8_t zero[baum->x * baum->y]; > + uint8_t cells[X_MAX * Y_MAX], c; > + uint8_t text[X_MAX * Y_MAX]; > + uint8_t zero[X_MAX * Y_MAX]; > int cursor = BRLAPI_CURSOR_OFF; > int i; > > @@ -408,7 +408,7 @@ static int baum_eat_packet(BaumChardev *baum, const > uint8_t *buf, int len) > } > timer_del(baum->cellCount_timer); > > - memset(zero, 0, sizeof(zero)); > + memset(zero, 0, baum->x * baum->y); > eh, I would have left the sizeof(zero).. > brlapi_writeArguments_t wa = { > .displayNumber = BRLAPI_DISPLAY_DEFAULT, > -- > 2.26.3 > > >
Marc-André Lureau, le jeu. 06 mai 2021 01:27:25 +0400, a ecrit: > @@ -408,7 +408,7 @@ static int baum_eat_packet(BaumChardev *baum, const > uint8_t *buf, int len) > } > timer_del(baum->cellCount_timer); > > - memset(zero, 0, sizeof(zero)); > + memset(zero, 0, baum->x * baum->y); > > > eh, I would have left the sizeof(zero).. I was wondering too, but below this it's clear that only baum->x * baum->y is getting used. Samuel
diff --git a/chardev/baum.c b/chardev/baum.c index adc3d7b3b56..0822e9ed5f3 100644 --- a/chardev/baum.c +++ b/chardev/baum.c @@ -383,9 +383,9 @@ static int baum_eat_packet(BaumChardev *baum, const uint8_t *buf, int len) switch (req) { case BAUM_REQ_DisplayData: { - uint8_t cells[baum->x * baum->y], c; - uint8_t text[baum->x * baum->y]; - uint8_t zero[baum->x * baum->y]; + uint8_t cells[X_MAX * Y_MAX], c; + uint8_t text[X_MAX * Y_MAX]; + uint8_t zero[X_MAX * Y_MAX]; int cursor = BRLAPI_CURSOR_OFF; int i; @@ -408,7 +408,7 @@ static int baum_eat_packet(BaumChardev *baum, const uint8_t *buf, int len) } timer_del(baum->cellCount_timer); - memset(zero, 0, sizeof(zero)); + memset(zero, 0, baum->x * baum->y); brlapi_writeArguments_t wa = { .displayNumber = BRLAPI_DISPLAY_DEFAULT,
We know 'x * y' will be at most 'X_MAX * Y_MAX' (which is not a big value, it is actually 84). Instead of having the compiler use variable-length array, declare an array able to hold the maximum 'x * y'. Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> --- chardev/baum.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)