diff --git a/include/sudo_iolog.h b/include/sudo_iolog.h
index 599424184..7535e284b 100644
--- a/include/sudo_iolog.h
+++ b/include/sudo_iolog.h
@@ -119,7 +119,7 @@ bool iolog_mkpath(char *path);
 bool iolog_nextid(const char *iolog_dir, char sessid[7]);
 bool iolog_open(struct iolog_file *iol, int dfd, int iofd, const char *mode);
 bool iolog_write_info_file(int dfd, struct eventlog *evlog);
-char *iolog_gets(struct iolog_file *iol, char *buf, size_t nbytes, const char **errsttr);
+char *iolog_gets(struct iolog_file *iol, char *buf, int bufsize, const char **errsttr);
 const char *iolog_fd_to_name(int iofd);
 int iolog_openat(int fdf, const char *path, int flags);
 off_t iolog_seek(struct iolog_file *iol, off_t offset, int whence);
diff --git a/lib/iolog/iolog_gets.c b/lib/iolog/iolog_gets.c
index 0ef5a2362..38d7eae28 100644
--- a/lib/iolog/iolog_gets.c
+++ b/lib/iolog/iolog_gets.c
@@ -40,16 +40,16 @@
 #include "sudo_iolog.h"
 
 /*
- * Like gets() but for struct iolog_file.
+ * Like fgets() but for struct iolog_file.
  */
 char *
-iolog_gets(struct iolog_file *iol, char *buf, size_t nbytes,
+iolog_gets(struct iolog_file *iol, char *buf, int bufsize,
     const char **errstr)
 {
     char *str;
     debug_decl(iolog_gets, SUDO_DEBUG_UTIL);
 
-    if (nbytes > UINT_MAX) {
+    if (bufsize < 0) {
 	errno = EINVAL;
 	if (errstr != NULL)
 	    *errstr = strerror(errno);
@@ -58,7 +58,7 @@ iolog_gets(struct iolog_file *iol, char *buf, size_t nbytes,
 
 #ifdef HAVE_ZLIB_H
     if (iol->compressed) {
-	if ((str = gzgets(iol->fd.g, buf, nbytes)) == NULL) {
+	if ((str = gzgets(iol->fd.g, buf, bufsize)) == NULL) {
 	    if (errstr != NULL) {
 		int errnum;
 		*errstr = gzerror(iol->fd.g, &errnum);
@@ -69,7 +69,7 @@ iolog_gets(struct iolog_file *iol, char *buf, size_t nbytes,
     } else
 #endif
     {
-	if ((str = fgets(buf, nbytes, iol->fd.f)) == NULL) {
+	if ((str = fgets(buf, bufsize, iol->fd.f)) == NULL) {
 	    if (errstr != NULL)
 		*errstr = strerror(errno);
 	}