tailf: Fix previously adjusted segfault patch

Casting the value to be checked to size_t renders the check useless.
If st_size is SIZE_MAX+1, it will be truncated to 0 and the check
succeeds. In fact, this check can never be false because every value
stored in a size_t is smaller or equal to SIZE_MAX.

I think this adjustment was meant to fix a compiler warning for 64 bit
systems for which sizeof(off_t) is sizeof(size_t), but the signedness
differs.

Going unconditionally to the greatest possible unsigned int type if
st_size is positive (off_t is signed) will fix this issue.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>

diff --git a/text-utils/tailf.c b/text-utils/tailf.c
index 6219aa21898eeecf0f419dda024f13129bd8560a..34d0cd53b18f4f233c63d450c3b48d8341b5da60 100644 (file)
--- a/text-utils/tailf.c
+++ b/text-utils/tailf.c
@@ -284,7 +284,7 @@ int main(int argc, char **argv)
                errx(EXIT_FAILURE, _("%s: is not a file"), filename);
 
        /* mmap is based on size_t */
-       if (st.st_size && (size_t) st.st_size <= SIZE_MAX)
+       if (st.st_size > 0 && (uintmax_t) st.st_size <= (uintmax_t) SIZE_MAX)
                tailf(filename, lines, &st);
 
 #ifdef HAVE_INOTIFY_INIT