Add readahead(8)

Makefile

@@ -51,6 +51,7 @@ SRC = \
 	pidof.c             \
 	pivot_root.c        \
 	ps.c                \
+	readahead.c         \
 	respawn.c           \
 	rmmod.c             \
 	stat.c              \

README

@@ -9,8 +9,8 @@ The following programs are currently implemented:
     chvt clear ctrlaltdel dd df dmesg eject fallocate free freeramdisk
     fsfreeze getty halt  hwclock id insmod killall5  login lsmod lsusb
     mknod mkswap mount mountpoint  pagesize passwd pidof pivot_root ps
-    respawn rmmod  stat su swapoff swapon  switch_root sysctl truncate
-    umount unshare uptime watch who
+    readahead respawn rmmod stat  su swapoff swapon switch_root sysctl
+    truncate umount unshare uptime watch who
 
 The complement  of ubase  is sbase[1] which  mostly follows  POSIX and
 provides all the portable tools.  Together they are intended to form a

TODO

@@ -16,7 +16,6 @@ Tools to be implemented
  * ifconfig
  * hwclock
  * partprobe
- * readahead
  * rfkill
  * taskset
  * acpi

readahead.c

@@ -0,0 +1,37 @@
+/* See LICENSE file for copyright and license details. */
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s file...\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	FILE *fp;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc == 0)
+		usage();
+
+	for (; argc > 0; argc--, argv++) {
+		if (!(fp = fopen(argv[0], "r"))) {
+			weprintf("fopen %s:", argv[0]);
+			continue;
+		}
+		if (readahead(fileno(fp), 0, -1) < 0)
+			weprintf("readahead %s:", argv[0]);
+		fclose(fp);
+	}
+	return EXIT_SUCCESS;
+}