49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
/* vi: set sw=4 ts=4: */
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/* mkswap.c - format swap device (Linux v1 only)
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*
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* Copyright 2006 Rob Landley <rob@landley.net>
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*
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* Licensed under GPL version 2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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int mkswap_main(int argc, char **argv);
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int mkswap_main(int argc, char **argv)
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{
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int fd, pagesize;
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off_t len;
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unsigned int hdr[129];
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// No options supported.
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if (argc != 2) bb_show_usage();
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// Figure out how big the device is and announce our intentions.
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fd = xopen(argv[1], O_RDWR);
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len = fdlength(fd);
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pagesize = getpagesize();
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printf("Setting up swapspace version 1, size = %"OFF_FMT"d bytes\n",
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len - pagesize);
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// Make a header.
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memset(hdr, 0, sizeof(hdr));
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hdr[0] = 1;
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hdr[1] = (len / pagesize) - 1;
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// Write the header. Sync to disk because some kernel versions check
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// signature on disk (not in cache) during swapon.
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xlseek(fd, 1024, SEEK_SET);
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xwrite(fd, hdr, sizeof(hdr));
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xlseek(fd, pagesize-10, SEEK_SET);
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xwrite(fd, "SWAPSPACE2", 10);
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fsync(fd);
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if (ENABLE_FEATURE_CLEAN_UP) close(fd);
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return 0;
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}
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