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chroot(2) [sunos 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 ENOLINK The path argument points to a remote machine and the link to that machine is no longer active.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 5.10 20 Jan 2003 chroot(2)

Check Out this Related Man Page

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

NAME
chroot -- change root directory LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int chroot(const char *dirname); int fchroot(int fd); 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 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. 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] dirname points outside the process's allocated address space. [EIO] An I/O error occurred while reading from or writing to the file system. [EPERM] The effective user ID of the calling process is not the super-user. fchroot() will fail and the root directory will be unchanged if: [EACCES] Search permission is denied for the directory referenced by the file descriptor. [EBADF] The argument fd is not a valid file descriptor. [EIO] An I/O error occurred while reading from or writing to the file system. [ENOTDIR] The argument fd does not reference a directory. [EPERM] The effective user ID of the calling process is not the super-user. SEE ALSO
chdir(2) STANDARDS
The 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''). HISTORY
The 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. BSD
April 18, 2001 BSD

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