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32 .\" @(#)chroot.2 8.1 (Berkeley) 6/4/93
33 .\" $FreeBSD: src/lib/libc/sys/chroot.2,v 1.7.2.8 2002/12/11 14:06:37 ru Exp $
40 .Nd change root directory
46 .Fn chroot "const char *dirname"
48 .Fn chroot_kernel "const char *dirname"
51 is the address of the pathname of a directory, terminated by an ASCII NUL.
55 to become the root directory,
56 that is, the starting point for path searches of pathnames
60 In order for a directory to become the root directory
61 a process must have execute (search) access for that directory.
63 It should be noted that
65 has no effect on the process's current directory.
67 This call is restricted to the super-user.
69 Depending on the setting of the
70 .Va kern.chroot_allow_open_directories
71 sysctl variable, open filedescriptors which reference directories
77 .Va kern.chroot_allow_open_directories
82 if there are any directories open.
85 .Va kern.chroot_allow_open_directories
86 is set to one (the default),
90 if there are any directories open and the
91 process is already subject to a
96 .Va kern.chroot_allow_open_directories
97 will bypass the check for open directories
99 Upon successful completion, a value of 0 is returned. Otherwise,
100 a value of -1 is returned and
102 is set to indicate an error.
106 system call adjusts the kernel's internal namecache and root vnode
109 If used in conjunction with
111 during early boot, it allows for changing the root mount to any
112 mount point available at that time.
115 will fail and the root directory will be unchanged if:
118 A component of the path name is not a directory.
120 The effective user ID is not the super-user, or one or more
121 filedescriptors are open directories.
122 .It Bq Er ENAMETOOLONG
123 A component of a pathname exceeded 255 characters,
124 or an entire path name exceeded 1023 characters.
126 The named directory does not exist.
128 Search permission is denied for any component of the path name.
130 Too many symbolic links were encountered in translating the pathname.
133 points outside the process's allocated address space.
135 An I/O error occurred while reading from or writing to the file system.
143 function call appeared in