Getting Started with QNX Neutrino - QNX Software Systems

Writing a resource manager
© 2009, QNX Software Systems GmbH & Co. KG.
mode
nlink
File’s mode. These are the standard S_* values from ,
such as S_IFCHR, or in octal representation, such as 0664 to indicate
read/write permission for owner and group, and read-only permission
for other.
Number of links to the file, returned by the client’s stat() function call.
rdev
For a character special device, this field consists of a major and minor
device code (10 bits minor in the least-significant positions; next 6
bits are the major device number). For other types of devices,
contains the device number. (See below in “Of device numbers,
inodes, and our friend rdev,” for more discussion.)
The iofunc_mount_t mount structure
As with the OCB, you can extend the “normal” attributes structure with your own
data. See the “Advanced topics” section.
The mount structure contains information that’s common across multiple attributes
structures.
Here are the contents of the mount structure (from ):
typedef struct _iofunc_mount {
uint32_t flags;
uint32_t conf ;
dev_t
dev;
int32_t blocksize;
iofunc_funcs_t *funcs;
} iofunc_mount_t;
The flags member contains just one flag, IOFUNC_MOUNT_32BIT. This flag indicates
that offset in the OCB, and nbytes and inode in the attributes structure, are 32-bit. Note
that you can define your own flags in flags, using any of the bits from the constant
IOFUNC_MOUNT_FLAGS_PRIVATE.
The conf member contains the following flags:
IOFUNC_PC_CHOWN_RESTRICTED
Indicates if the filesystem is operating in a “chown-restricted” manner, meaning
if only root is allowed to chown a file.
IOFUNC_PC_NO_TRUNC
Indicates that the filesystem doesn’t truncate the name.
IOFUNC_PC_SYNC_IO
Indicates that the filesystem supports synchronous I/O operations.
IOFUNC_PC_LINK_DIR
Indicates that linking/unlinking of directories is allowed.
224 Chapter 5 • Resource Managers April 30, 2009