Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #380
Difficulty: Medium
Apple's macOS (previously known as Mac OS X or OS X) is a UNIX 03 registered product.
True or False?
Linux & Unix Commands - Search Man Pages

chroot(2) [osx man page]

CHROOT(2)						      BSD System Calls Manual							 CHROOT(2)

NAME
chroot -- change root directory SYNOPSIS
#include <unistd.h> int chroot(const char *dirname); DESCRIPTION
Dirname is the address of the pathname of a directory, terminated by an ASCII NUL. 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 program is not currently running with an altered root directory, it should be noted that chroot() has no effect on the process's cur- rent directory. If the program is already running with an altered root directory, the process's current directory is changed to the same new root directory. This prevents the current directory from being further up the directory tree than the altered root directory. This call is restricted to the super-user. RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate an error. ERRORS
Chroot() will fail and the root directory will be unchanged if: [ENOTDIR] A component of the path name is not a directory. [ENAMETOOLONG] A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters. [ENOENT] The named directory does not exist. [EACCES] Search permission is denied for any component of the path name. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EFAULT] Path points outside the process's allocated address space. [EIO] An I/O error occurred while reading from or writing to the file system. SEE ALSO
chdir(2) WARNINGS
There are ways for a root process to escape from the chroot jail. HISTORY
The chroot() function call appeared in 4.2BSD. 4.2 Berkeley Distribution June 4, 1993 4.2 Berkeley Distribution

Check Out this Related Man Page

chroot(2)							   System Calls 							 chroot(2)

NAME
chroot, fchroot - change root directory SYNOPSIS
#include <unistd.h> int chroot(const char *path); int fchroot(int fildes); DESCRIPTION
The chroot() and fchroot() functions cause a directory to become the root directory, the starting point for path searches for path names beginning with / (slash). The user's working directory is unaffected by the chroot() and fchroot() functions. The path argument points to a path name naming a directory. The fildes argument to fchroot() is the open file descriptor of the directory which is to become the root. The privilege {PRIV_PROC_CHROOT} must be asserted in the effective set of the process to change the root directory. While it is always pos- sible to change to the system root using the fchroot() function, it is not guaranteed to succeed in any other case, even if fildes is valid in all respects. The ".." entry in the root directory is interpreted to mean the root directory itself. Therefore, ".." cannot be used to access files out- side the subtree rooted at the root directory. Instead, fchroot() can be used to reset the root to a directory that was opened before the root directory was changed. RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is returned, the root directory remains unchanged, and errno is set to indicate the error. ERRORS
The chroot() function will fail if: EACCES Search permission is denied for a component of the path prefix of dirname, or search permission is denied for the directory referred to by dirname. EBADF The descriptor is not valid. EFAULT The path argument points to an illegal address. EINVAL The fchroot() function attempted to change to a directory the is not the system root and external circumstances do not allow this. EINTR A signal was caught during the execution of the chroot() function. EIO An I/O error occurred while reading from or writing to the file system. ELOOP Too many symbolic links were encountered in translating path. ENAMETOOLONG The length of the path argument exceeds PATH_MAX, or the length of a path component exceeds NAME_MAX while _POSIX_NO_TRUNC is in effect. ENOENT The named directory does not exist or is a null pathname. ENOLINK The path argument points to a remote machine and the link to that machine is no longer active. ENOTDIR Any component of the path name is not a directory. EPERM The {PRIV_PROC_CHROOT} privilege is not asserted in the effective set of the calling process. SEE ALSO
chroot(1M), chdir(2), privileges(5) WARNINGS
The only use of fchroot() that is appropriate is to change back to the system root. SunOS 5.11 20 Jan 2003 chroot(2)

Featured Tech Videos