A read() write() pair can be replaced with sendfile(), and it should be more
efficient than suffling bytes back and forth user and kernel space.
Signed-off-by: Sami Kerola <kerolasa@xxxxxxxxxxxxxx>
---
login-utils/nologin.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/login-utils/nologin.c b/login-utils/nologin.c
index f38a3aab0..ca4ca4e84 100644
--- a/login-utils/nologin.c
+++ b/login-utils/nologin.c
@@ -3,6 +3,7 @@
*/
#include <stdio.h>
+#include <sys/sendfile.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
@@ -97,12 +98,12 @@ int main(int argc, char *argv[])
if (c < 0 || !S_ISREG(st.st_mode))
goto dflt;
else {
- char buf[BUFSIZ];
- ssize_t rd;
-
- while ((rd = read(fd, buf, sizeof(buf))) > 0)
- ignore_result( write(STDOUT_FILENO, buf, rd) );
+ int stdout_fd;
+ stdout_fd = fileno(stdout);
+ if (stdout_fd < 0)
+ goto dflt;
+ ignore_result( sendfile(stdout_fd, fd, NULL, st.st_size) );
close(fd);
return EXIT_FAILURE;
}
--
2.28.0
