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Diffstat (limited to 'lib/libc/sys/chroot.2')
-rw-r--r-- | lib/libc/sys/chroot.2 | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/lib/libc/sys/chroot.2 b/lib/libc/sys/chroot.2 new file mode 100644 index 0000000..ecf2eb5 --- /dev/null +++ b/lib/libc/sys/chroot.2 @@ -0,0 +1,142 @@ +.\" Copyright (c) 1983, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)chroot.2 8.1 (Berkeley) 6/4/93 +.\" $FreeBSD$ +.\" +.Dd June 4, 1993 +.Dt CHROOT 2 +.Os +.Sh NAME +.Nm chroot +.Nd change root directory +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In unistd.h +.Ft int +.Fn chroot "const char *dirname" +.Sh DESCRIPTION +The +.Fa dirname +argument +is the address of the pathname of a directory, terminated by an ASCII NUL. +The +.Fn chroot +system call causes +.Fa dirname +to become the root directory, +that is, the starting point for path searches of pathnames +beginning with +.Ql / . +.Pp +In order for a directory to become the root directory +a process must have execute (search) access for that directory. +.Pp +It should be noted that +.Fn chroot +has no effect on the process's current directory. +.Pp +This call is restricted to the super-user. +.Pp +Depending on the setting of the +.Ql kern.chroot_allow_open_directories +sysctl variable, open filedescriptors which reference directories +will make the +.Fn chroot +fail as follows: +.Pp +If +.Ql kern.chroot_allow_open_directories +is set to zero, +.Fn chroot +will always fail with +.Er EPERM +if there are any directories open. +.Pp +If +.Ql kern.chroot_allow_open_directories +is set to one (the default), +.Fn chroot +will fail with +.Er EPERM +if there are any directories open and the +process is already subject to the +.Fn chroot +system call. +.Pp +Any other value for +.Ql kern.chroot_allow_open_directories +will bypass the check for open directories +.Pp +Upon successful completion, a value of 0 is returned. +Otherwise, +a value of -1 is returned and +.Va errno +is set to indicate an error. +.Sh ERRORS +The +.Fn chroot +system call +will fail and the root directory will be unchanged if: +.Bl -tag -width Er +.It Bq Er ENOTDIR +A component of the path name is not a directory. +.It Bq Er EPERM +The effective user ID is not the super-user, or one or more +filedescriptors are open directories. +.It Bq Er ENAMETOOLONG +A component of a pathname exceeded 255 characters, +or an entire path name exceeded 1023 characters. +.It Bq Er ENOENT +The named directory does not exist. +.It Bq Er EACCES +Search permission is denied for any component of the path name. +.It Bq Er ELOOP +Too many symbolic links were encountered in translating the pathname. +.It Bq Er EFAULT +The +.Fa dirname +argument +points outside the process's allocated address space. +.It Bq Er EIO +An I/O error occurred while reading from or writing to the file system. +.El +.Sh SEE ALSO +.Xr chdir 2 , +.Xr jail 2 +.Sh HISTORY +The +.Fn chroot +system call appeared in +.Bx 4.2 . +.Sh BUGS +If the process is able to change its working directory to the target +directory, but another access control check fails (such as a check for +open directories, or a MAC check), it is possible that this system +call may return an error, with the working directory of the process +left changed. |