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28 .\" @(#)chroot.2 8.1 (Berkeley) 6/4/93
29 .\" $FreeBSD: src/lib/libc/sys/chroot.2,v 1.7.2.8 2002/12/11 14:06:37 ru Exp $
37 .Nd change root directory
43 .Fn chroot "const char *dirname"
45 .Fn chroot_kernel "const char *dirname"
48 is the address of the pathname of a directory, terminated by an ASCII NUL.
52 to become the root directory,
53 that is, the starting point for path searches of pathnames
57 In order for a directory to become the root directory
58 a process must have execute (search) access for that directory.
60 It should be noted that
62 has no effect on the process's current directory.
64 This call is restricted to the super-user.
66 Depending on the setting of the
67 .Va kern.chroot_allow_open_directories
68 sysctl variable, open filedescriptors which reference directories
74 .Va kern.chroot_allow_open_directories
79 if there are any directories open.
82 .Va kern.chroot_allow_open_directories
83 is set to one (the default),
87 if there are any directories open and the
88 process is already subject to a
93 .Va kern.chroot_allow_open_directories
94 will bypass the check for open directories
96 Upon successful completion, a value of 0 is returned. Otherwise,
97 a value of -1 is returned and
99 is set to indicate an error.
103 system call adjusts the kernel's internal namecache and root vnode
106 If used in conjunction with
108 during early boot, it allows for changing the root mount to any
109 mount point available at that time.
112 will fail and the root directory will be unchanged if:
115 A component of the path name is not a directory.
117 The effective user ID is not the super-user, or one or more
118 filedescriptors are open directories.
119 .It Bq Er ENAMETOOLONG
120 A component of a pathname exceeded 255 characters,
121 or an entire path name exceeded 1023 characters.
123 The named directory does not exist.
125 Search permission is denied for any component of the path name.
127 Too many symbolic links were encountered in translating the pathname.
130 points outside the process's allocated address space.
132 An I/O error occurred while reading from or writing to the file system.
140 function call appeared in