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chown(2) [osx man page]

CHOWN(2)						      BSD System Calls Manual							  CHOWN(2)

NAME
chown, fchown, lchown -- change owner and group of a file SYNOPSIS
#include <unistd.h> int chown(const char *path, uid_t owner, gid_t group); int fchown(int fildes, uid_t owner, gid_t group); int lchown(const char *path, uid_t owner, gid_t group); DESCRIPTION
The owner ID and group ID of the file named by path or referenced by fildes is changed as specified by the arguments owner and group. The owner of a file may change the group to a group of which he or she is a member, but the change owner capability is restricted to the super- user. The chown() system call clears the set-user-id and set-group-id bits on the file to prevent accidental or mischievous creation of set-user-id and set-group-id programs if not executed by the super-user. The chown() system call follows symbolic links to operate on the target of the link rather than the link itself. The fchown() system call is particularly useful when used in conjunction with the file locking primitives (see flock(2)). The lchown() system call is similar to chown() but does not follow symbolic links. One of the owner or group id's may be left unchanged by specifying it as -1. RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
The chown() and lchown() system calls will fail if: [EACCES] Search permission is denied for a component of the path prefix. [EFAULT] The path argument points outside the process's allocated address space. [ELOOP] Too many symbolic links are encountered in translating the pathname. This is taken to be indicative of a looping symbolic link. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [ENOENT] A component of path does not exist. [ENOTDIR] A component of the path prefix is not a directory. The fchown() system call will fail if: [EBADF] The fildes argument does not refer to a valid descriptor. [EINVAL] The fildes argument refers to a socket, not a file. Any of these calls will fail if: [EINTR] Its execution is interrupted by a signal. [EIO] An I/O error occurs while reading from or writing to the file system. [EPERM] The effective user ID does not match the owner of the file and the calling process does not have appropriate (i.e., root) privileges. [EROFS] The named file resides on a read-only file system. SEE ALSO
chgrp(1), chmod(2), flock(2), chown(8) STANDARDS
The chown() system call is expected to conform to ISO/IEC 9945-1:1990 (``POSIX.1''). HISTORY
The chown() function appeared in Version 7 AT&T UNIX. The fchown() system call appeared in 4.2BSD. The chown() and fchown() system calls were changed to follow symbolic links in 4.4BSD. The lchown() system call was added in FreeBSD 3.0 to compensate for the loss of functionality. BSD
April 19, 1994 BSD

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CHOWN(2)						      BSD System Calls Manual							  CHOWN(2)

NAME
chown, lchown, fchown -- change owner and group of a file LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int chown(const char *path, uid_t owner, gid_t group); int lchown(const char *path, uid_t owner, gid_t group); int fchown(int fd, uid_t owner, gid_t group); DESCRIPTION
The owner ID and group ID of the file named by path or referenced by fd is changed as specified by the arguments owner and group. The owner of a file may change the group to a group of which he or she is a member, but the change owner capability is restricted to the super-user. When called to change the owner of a file, chown(), lchown() and fchown() clear the set-user-id (S_ISUID) bit on the file. When a called to change the group of a file, chown(), lchown() and fchown() clear the set-group-id (S_ISGID) bit on the file. These actions are taken to pre- vent accidental or mischievous creation of set-user-id and set-group-id programs. lchown() is like chown() except in the case where the named file is a symbolic link, in which case lchown() changes the owner and group of the link, while chown() changes the owner and group of the file the link references. fchown() is particularly useful when used in conjunction with the file locking primitives (see flock(2)). One of the owner or group id's may be left unchanged by specifying it as (uid_t)-1 or (gid_t)-1 respectively. RETURN VALUES
Zero is returned if the operation was successful; -1 is returned if an error occurs, with a more specific error code being placed in the global variable errno. ERRORS
chown() and lchown() will fail and the file will be unchanged if: [ENOTDIR] A component of the path prefix 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 file does not exist. [EACCES] Search permission is denied for a component of the path prefix. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EPERM] The effective user ID is not the super-user. [EROFS] The named file resides on a read-only file system. [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. fchown() will fail if: [EBADF] fd does not refer to a valid descriptor. [EINVAL] fd refers to a socket, not a file. [EPERM] The effective user ID is not the super-user. [EROFS] The named file resides on a read-only file system. [EIO] An I/O error occurred while reading from or writing to the file system. SEE ALSO
chgrp(1), chmod(2), flock(2), symlink(7), chown(8) STANDARDS
The chown() function deviates from the semantics defined in ISO/IEC 9945-1:1990 (``POSIX.1''), which specifies that, unless the caller is the super-user, both the set-user-id and set-group-id bits on a file shall be cleared, regardless of the file attribute changed. The lchown() and fchown() functions, as defined by X/Open Portability Guide Issue 4, Version 2 (``XPG4.2''), provide the same semantics. To retain conformance to these standards, compatibility interfaces are provided by the POSIX Compatibility Library (libposix, -lposix) as follows: o The chown() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'') and X/Open Portability Guide Issue 4, Version 2 (``XPG4.2''). o The lchown() and fchown() functions conform to X/Open Portability Guide Issue 4, Version 2 (``XPG4.2''). HISTORY
The fchown() function call appeared in 4.2BSD. The chown() and fchown() functions were changed to follow symbolic links in 4.4BSD. The lchown() function call appeared in NetBSD 1.3. BSD
April 19, 1994 BSD

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