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-rw-r--r--toys/mkswap.c42
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diff --git a/toys/mkswap.c b/toys/mkswap.c
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+/* vi: set sw=4 ts=4:
+ *
+ * mkswap.c - Format swap device.
+ *
+ * Copyright 2009 Rob Landley <rob@landley.net>
+ *
+ * Not in SUSv3.
+
+USE_MKSWAP(NEWTOY(mkswap, "<1>2", TOYFLAG_SBIN))
+
+config MKSWAP
+ bool "mkswap"
+ default y
+ help
+ usage: mkswap DEVICE
+
+ Format a Linux v1 swap device.
+*/
+
+#include "toys.h"
+
+void mkswap_main(void)
+{
+ int fd = xopen(*toys.optargs, O_RDWR), pagesize = getpagesize();
+ off_t len = fdlength(fd);
+ unsigned int pages = (len/pagesize)-1, *swap = (unsigned int *)toybuf;
+
+ // Write header. Note that older kernel versions checked signature
+ // on disk (not in cache) during swapon, so sync after writing.
+
+ swap[0] = 1;
+ swap[1] = pages;
+ xlseek(fd, 1024, SEEK_SET);
+ xwrite(fd, swap, 129*sizeof(unsigned int));
+ xlseek(fd, pagesize-10, SEEK_SET);
+ xwrite(fd, "SWAPSPACE2", 10);
+ fsync(fd);
+
+ if (CFG_TOYBOX_FREE) close(fd);
+
+ printf("Swapspace size: %luk\n", pages*(unsigned long)(pagesize/1024));
+}