inotail.c: Fix an integer underflow in bytes_to_offset()

This also caused the bug that nothing was printed when a number greater
than the number of characters in the file was specifed with the -c
parameter.

1 files changed, 3 insertions, 2 deletions

diff --git a/inotail.c b/inotail.c
index 006f28f..0c278e2 100644
--- a/inotail.c
+++ b/inotail.c
@@ -198,8 +198,9 @@ static off_t lines_to_offset(struct file_struct *f, unsigned long n_lines)
 
 static off_t bytes_to_offset(struct file_struct *f, unsigned long n_bytes)
 {
-	/* tail everything for 'inotail -c +0' */
-	if (from_begin && n_bytes == 0)
+	/* tail everything for 'inotail -c +0' or if n_bytes greater than the
+	 * total amount of chars in the file */
+	if ((from_begin && n_bytes == 0) || ((off_t) n_bytes > f->st_size))
 		return 0;
 	else
 		return (from_begin ? ((off_t) n_bytes - 1) : (f->st_size - (off_t) n_bytes));