grantpt(3C) Standard C Library Functions grantpt(3C)NAME
grantpt - grant access to the slave pseudo-terminal device
SYNOPSIS
#include <stdlib.h>
int grantpt(int fildes);
DESCRIPTION
The grantpt() function changes the mode and ownership of the slave pseudo-terminal device associated with its master pseudo-terminal
counterpart. fildes is the file descriptor returned from a successful open of the master pseudo-terminal device. A setuid root program (see
setuid(2)) is invoked to change the permissions. The user ID of the slave is set to the real UID of the calling process and the group ID is
set to a reserved group. The permission mode of the slave pseudo-terminal is set to readable and writable by the owner and writable by the
group.
RETURN VALUES
Upon successful completion, grantpt() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.
ERRORS
The grantpt() function may fail if:
EBADF The fildes argument is not a valid open file descriptor.
EINVAL The fildes argument is not associated with a master pseudo-terminal device.
EACCES The corresponding slave pseudo-terminal device could not be accessed.
USAGE
The grantpt() function will fail if it is unable to successfully invoke the setuid root program. It may also fail if the application has
installed a signal handler to catch SIGCHLD signals.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Safe |
+-----------------------------+-----------------------------+
SEE ALSO open(2), setuid(2), ptsname(3C), unlockpt(3C), attributes(5), standards(5)
STREAMS Programming Guide
SunOS 5.10 29 Dec 1996 grantpt(3C)
Check Out this Related Man Page
GRANTPT(3) BSD Library Functions Manual GRANTPT(3)NAME
grantpt, posix_openpt, ptsname, unlockpt -- pseudo-terminal access functions
SYNOPSIS
#include <stdlib.h>
int
grantpt(int fildes);
char *
ptsname(int fildes);
int
unlockpt(int fildes);
#include <stdlib.h>
#include <fcntl.h>
int
posix_openpt(int oflag);
DESCRIPTION
The grantpt(), ptsname(), unlockpt(), and posix_openpt() functions allow access to pseudo-terminal devices. The first three functions accept
a file descriptor that references the master half of a pseudo-terminal pair. This file descriptor is created with posix_openpt().
The grantpt() function is used to establish ownership and permissions of the slave device counterpart to the master device specified with
fildes. The slave device's ownership is set to the real user ID of the calling process; its permissions are set to user readable-writable
and group writable. The group owner of the slave device is also set to the group ``tty'' if it exists on the system; otherwise, it is left
untouched.
The ptsname() function returns the full pathname of the slave device counterpart to the master device specified with fildes. This value can
be used to subsequently open the appropriate slave after posix_openpt() and grantpt() have been called.
The unlockpt() function unlocks the slave pseudo-terminal device associated with the master device to which fildes refers.
The posix_openpt() function opens the first available master pseudo-terminal device and returns a descriptor to it. The oflag argument spec-
ifies the flags used for opening the device:
O_RDWR Open for reading and writing.
O_NOCTTY If set, do not allow the terminal to become the controlling terminal for the calling process.
RETURN VALUES
The grantpt() and unlockpt() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable errno is
set to indicate the error.
The ptsname() function returns a pointer to the name of the slave device on success; otherwise a NULL pointer is returned and the global
variable errno is set to indicate the error.
The posix_openpt() function returns a file descriptor to the first available master pseudo-terminal device on success; otherwise -1 is
returned and the global variable errno is set to indicate the error.
ERRORS
The grantpt(), ptsname(), and unlockpt() functions may fail and set errno to:
[EINVAL] fildes is not a master pseudo-terminal device.
In addition, the grantpt() function may set errno to:
[EACCES] The slave pseudo-terminal device could not be accessed.
The posix_openpt() function may fail and set errno to:
[EINVAL] oflag consists of an invalid mode bit.
[EAGAIN] The system has no available pseudo-terminal devices.
The grantpt(), ptsname(), and unlockpt() functions may also fail and set errno for any of the errors specified for the fstat(2) system call.
The posix_openpt() function may also fail and set errno for any of the errors specified for the open(2) system call.
LEGACY SYNOPSIS
#include <stdlib.h>
#include <fcntl.h>
int
grantpt(int fildes);
char *
ptsname(int fildes);
int
unlockpt(int fildes);
#include <fcntl.h>
int
posix_openpt(int oflag);
SEE ALSO open(2), pty(4), tty(4), compat(5)STANDARDS
The grantpt(), ptsname(), unlockpt(), and posix_openpt() functions conform to IEEE Std 1003.1-2001 (``POSIX.1'').
BSD February 2, 2005 BSD