Open System Services System Calls Reference Manual (G06.25+, H06.03+)

umask(2) OSS System Calls Reference Manual
NAME
umask - Sets and gets the value of the file mode creation mask
LIBRARY
G-series native OSS processes: system library
H-series OSS processes: implicit libraries
SYNOPSIS
#include <sys/types.h> /* optional except for POSIX.1 */
#include <sys/stat.h>
mode_t umask(
mode_t cmask);
PARAMETERS
cmask Specifies the value of the file mode creation mask.
DESCRIPTION
The umask( ) function sets the file mode creation mask of the process to the value of the cmask
parameter and returns the previous value of the mask. The cmask parameter is constructed by
logically ORing file permission bits defined in the sys/stat.h header file.
Whenever a file is created (by the creat(), mkdir( ), mkfifo(), mknod( ),oropen() function), all
file permission bits set in the file mode creation mask are cleared in the mode of the created file.
This clearing allows users to restrict the default access to their files.
The mask is inherited by child processes.
Use on Guardian Objects
The file mode creation mask of the process is not used when accessing a file in /G (the Guardian
file system). If an open causes file creation, the file is given access permissions compatible with
the standard security permissions for the Guardian creator access ID (CAID) of the calling pro-
cess.
During access to a Guardian file, all Guardian environment access permissions are checked. This
includes checks by Guardian standard security mechanisms and by the Safeguard product for
Guardian disk file and process access.
RETURN VALUES
Upon successful completion, the previous value of the file mode creation mask is returned.
RELATED INFORMATION
Commands: chmod(1), mkdir(1), sh(1), umask(1).
Functions: chmod(2), mkdir(2), mkfifo(3), mknod(2), open(2), stat(2).
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