Add mkswap(8)

No manpage yet.

Makefile

@@ -20,6 +20,7 @@ ifeq ($(OS),linux)
 SRC += \
 	insmod.c            \
 	lsmod.c             \
+	mkswap.c            \
 	rmmod.c
 endif
 

mkswap.c

@@ -0,0 +1,83 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "util.h"
+
+enum { SWAP_UUID_LENGTH = 16, SWAP_LABEL_LENGTH = 16 };
+enum { SWAP_MIN_PAGES = 10 };
+
+struct swap_hdr {
+	char	      bootbits[1024];
+	unsigned int  version;
+	unsigned int  last_page;
+	unsigned int  nr_badpages;
+	unsigned char uuid[SWAP_UUID_LENGTH];
+	char	      volume_name[SWAP_LABEL_LENGTH];
+	unsigned int  padding[117];
+	unsigned int  badpages[1];
+};
+
+static void
+usage(void)
+{
+	eprintf("usage: %s <filename|device>\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int fd;
+	unsigned int pages;
+	long pagesize;
+	struct stat sb;
+	char *buf;
+	struct swap_hdr *hdr;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc < 1)
+		usage();
+
+	pagesize = sysconf(_SC_PAGE_SIZE);
+
+	fd = open(argv[0], O_RDWR);
+	if (fd < 0)
+		eprintf("open %s:", argv[0]);
+	if (fstat(fd, &sb) < 0)
+		eprintf("stat %s:", argv[0]);
+
+	buf = calloc(1, pagesize);
+	if (!buf)
+		eprintf("malloc:");
+
+	pages = sb.st_size / pagesize;
+	if (pages < SWAP_MIN_PAGES)
+		enprintf(1, "swap space needs to be at least %ldKiB\n",
+			 SWAP_MIN_PAGES * pagesize / 1024);
+
+	/* Fill up the swap header */
+	hdr = (struct swap_hdr *)buf;
+	hdr->version = 1;
+	hdr->last_page = pages - 1;
+	strncpy(buf + pagesize - 10, "SWAPSPACE2", 10);
+
+	printf("Setting up swapspace version 1, size = %luKiB\n",
+	       (pages - 1) * pagesize / 1024);
+
+	/* Write out the signature page */
+	if (write(fd, buf, pagesize) != pagesize)
+		enprintf(1, "unable to write signature page\n");
+
+	fsync(fd);
+	close(fd);
+	free(buf);
+
+	return 0;
+}