mirror of https://github.com/mkerrisk/man-pages
115 lines
3.2 KiB
Plaintext
115 lines
3.2 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "FCHMOD" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" fchmod
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.SH NAME
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fchmod \- change mode of a file
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.SH SYNOPSIS
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.LP
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\fB#include <sys/stat.h>
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.br
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.sp
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int fchmod(int\fP \fIfildes\fP\fB, mode_t\fP \fImode\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIfchmod\fP() function shall be equivalent to \fIchmod\fP() except
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that the file
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whose permissions are changed is specified by the file descriptor
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\fIfildes\fP.
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.LP
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If \fIfildes\fP references a shared memory object, the \fIfchmod\fP()
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function need only affect the S_IRUSR, S_IWUSR, S_IRGRP,
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S_IWGRP, S_IROTH, and S_IWOTH file permission bits.
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.LP
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If \fIfildes\fP references a typed memory object, the behavior of
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\fIfchmod\fP() is unspecified.
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.LP
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If \fIfildes\fP refers to a socket, the behavior of \fIfchmod\fP()
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is unspecified.
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.LP
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If \fIfildes\fP refers to a STREAM (which is \fIfattach\fP()-ed into
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the file system name
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space) the call returns successfully, doing nothing.
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIfchmod\fP() shall return 0. Otherwise,
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it shall return -1 and set \fIerrno\fP to indicate the
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error.
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.SH ERRORS
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.LP
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The \fIfchmod\fP() function shall fail if:
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.TP 7
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.B EBADF
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The \fIfildes\fP argument is not an open file descriptor.
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.TP 7
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.B EPERM
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The effective user ID does not match the owner of the file and the
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process does not have appropriate privilege.
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.TP 7
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.B EROFS
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The file referred to by \fIfildes\fP resides on a read-only file system.
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.sp
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.LP
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The \fIfchmod\fP() function may fail if:
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.TP 7
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.B EINTR
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The \fIfchmod\fP() function was interrupted by a signal.
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.TP 7
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.B EINVAL
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The value of the \fImode\fP argument is invalid.
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.TP 7
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.B EINVAL
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The \fIfildes\fP argument refers to a pipe and the implementation
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disallows execution of \fIfchmod\fP() on a pipe.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.SS Changing the Current Permissions for a File
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.LP
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The following example shows how to change the permissions for a file
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named \fB/home/cnd/mod1\fP so that the owner and group
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have read/write/execute permissions, but the world only has read/write
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permissions.
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.sp
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.RS
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.nf
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\fB#include <sys/stat.h>
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#include <fcntl.h>
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.sp
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mode_t mode;
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int fildes;
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\&...
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fildes = open("/home/cnd/mod1", O_RDWR);
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fchmod(fildes, S_IRWXU | S_IRWXG | S_IROTH | S_IWOTH);
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\fP
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.fi
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.RE
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIchmod\fP() , \fIchown\fP() , \fIcreat\fP() , \fIfcntl\fP() , \fIfstatvfs\fP()
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, \fImknod\fP() , \fIopen\fP() , \fIread\fP() , \fIstat\fP() , \fIwrite\fP()
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, the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<sys/stat.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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