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929
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1 /* pivot_root.c - edit system mount tree
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2 *
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3 * Copyright 2012 Rob Landley <rob@landley.net>
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4
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5 USE_PIVOT_ROOT(NEWTOY(pivot_root, "<2>2", TOYFLAG_USR|TOYFLAG_BIN))
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6
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7 config PIVOT_ROOT
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8 bool "pivot_root"
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9 default y
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10 help
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11 usage: pivot_root OLD NEW
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12
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13 Swap OLD and NEW filesystems (as if by simultaneous mount --move), and
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14 move all processes with chdir or chroot under OLD into NEW (including
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15 kernel threads) so OLD may be unmounted.
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16
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17 The directory NEW must exist under OLD. This doesn't work on initramfs,
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18 which can't be moved (about the same way PID 1 can't be killed; see
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19 switch_root instead).
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20 */
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21
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22 #define FOR_pivot_root
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23 #include "toys.h"
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24
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25 #include <linux/unistd.h>
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26
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27 void pivot_root_main(void)
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28 {
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29 if (syscall(__NR_pivot_root, toys.optargs[0], toys.optargs[1]))
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30 perror_exit("'%s' -> '%s'", toys.optargs[0], toys.optargs[1]);
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31 }
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