| Message ID | 0d8325c242cc19f74149bfe721e395bf4de951df.1527639529.git.rodrigosiqueiramelo@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Title is slightly missleading. We don't remove extra NULL characer from anywhere. We just account for it by subtracting 1 from the destination buffer size. So maybe "Account for NULL character when using strncpy"? On Tue, May 29, 2018 at 09:46:55PM -0300, Rodrigo Siqueira wrote: > This patch fix the following gcc warning: > > warning: ‘strncpy’ specified bound 32 equals destination size > [-Wstringop-truncation] > strncpy(data->name, name, PARAM_NAME_MAX_SZ); > > This error happens due to the '\0' character appended by strncpy. Notice > that reduces by one in the total of bytes to be copied, in this case, is > harmless because the strings received in the parameter already have > '\0'. > > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> > --- > lib/igt_aux.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/igt_aux.c b/lib/igt_aux.c > index 5dd2761e..06f586d6 100644 > --- a/lib/igt_aux.c > +++ b/lib/igt_aux.c > @@ -1240,7 +1240,7 @@ static void igt_save_module_param(const char *name, const char *file_path) > data = calloc(1, sizeof (*data)); > igt_assert(data); > > - strncpy(data->name, name, PARAM_NAME_MAX_SZ); > + strncpy(data->name, name, PARAM_NAME_MAX_SZ - 1); // -1 because of '\0' I am not necessary sure that the comment is needed, as "buflen - 1" is quite typical.
diff --git a/lib/igt_aux.c b/lib/igt_aux.c index 5dd2761e..06f586d6 100644 --- a/lib/igt_aux.c +++ b/lib/igt_aux.c @@ -1240,7 +1240,7 @@ static void igt_save_module_param(const char *name, const char *file_path) data = calloc(1, sizeof (*data)); igt_assert(data); - strncpy(data->name, name, PARAM_NAME_MAX_SZ); + strncpy(data->name, name, PARAM_NAME_MAX_SZ - 1); // -1 because of '\0' fd = open(file_path, O_RDONLY); igt_assert(fd >= 0);
This patch fix the following gcc warning: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation] strncpy(data->name, name, PARAM_NAME_MAX_SZ); This error happens due to the '\0' character appended by strncpy. Notice that reduces by one in the total of bytes to be copied, in this case, is harmless because the strings received in the parameter already have '\0'. Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> --- lib/igt_aux.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)