CHROOT(2) | System Calls Manual | CHROOT(2) |
chroot
, fchroot
—
#include <unistd.h>
int
chroot
(const
char *dirname);
int
fchroot
(int
fd);
chroot
() causes
dirname to become the root directory, that is, the
starting point for path searches of pathnames beginning with
‘/
’.
In order for a directory to become the root directory a process must have execute (search) access for that directory.
If the current working directory is not at or under the new root
directory, it is silently set to the new root directory. It should be noted
that, on most other systems, chroot
() has no effect
on the process's current directory.
This call is restricted to the super-user.
The fchroot
() function performs the same
operation on an open directory file known by the file descriptor
fd.
chroot
() will fail and the root directory will be
unchanged if:
EACCES
]EFAULT
]EIO
]ELOOP
]ENAMETOOLONG
]NAME_MAX
}
characters, or an entire path name exceeded
{PATH_MAX
} characters.ENOENT
]ENOTDIR
]EPERM
]fchroot
() will fail and the root directory
will be unchanged if:
EACCES
]EBADF
]EIO
]ENOTDIR
]EPERM
]chroot
() function conforms to
X/Open System Interfaces and Headers Issue 5
(“XSH5”), with the restriction that the calling process'
working directory must be at or under the new root directory. Otherwise, the
working directory is silently set to the new root directory; this is an
extension to the standard.
chroot
() was declared a legacy interface,
and subsequently removed in IEEE Std 1003.1-2001
(“POSIX.1”).
chroot
() function call appeared in
4.2BSD. Working directory handling was changed in
NetBSD 1.4 to prevent one way a process could use a
second chroot
() call to a different directory to
"escape" from the restricted subtree. The
fchroot
() function appeared in NetBSD
1.4.
April 18, 2001 | NetBSD 9.0 |