Veritas™ File System 5.0.1 Programmer's Reference Guide

To list named data streams

To list the named data streams, create code similar to the following:

fd = open("foo", O_RDWR); /* open file foo */

afd = vxfs_nattr_open(fd, "stream1",

O_RDWR|O_CREAT, 0777);/* create named data stream

stream1 for file foo */

write(afd, buf, 1024); /* writes to named stream file */

read(afd, buf, 1024); /* reads from named stream file */

dfd = vxfs_nattr_open(fd, ".", O_RDONLY);

/* opens named stream directory

for file foo */

getdents(dfd, buf, 1024);/* reads directory entries for

named stream directory */

Use the reverse name lookup call to resolve a stream file to a pathname. The

resulting pathname’s format is similar to the following:

/mount_point/file_with_data_stream/./data_stream_file_name

Namespace for named data streams

Names starting with “$vxfs:” are reserved for future use. Creating a data stream

in which the name starts with “$vxfs:” fails with an EINVAL error.

Behavior changes in other system calls

Although the named data stream directory is hidden from the namespace, it is

possible to open the name data stream directory inode with a fchdir() or fchroot()

call. Some of the attributes, such as “..”, are not defined for a named data streams

directory. Any operation that accesses these fields can fail. Attempts to create

directories, symbolic links, or device files on a named data stream directory fail.

VOP_SETATTR() called on a named data stream directory or named data stream

inode also fails.

The following is an alternative method for reading the hidden directory using the

fchdir() call:

fd = open(filename, O_RDONLY)

dfd = vxfs_nattr_open(fd, ".", O_RDONLY, mode)

fchdir(dfd);

67Named data streams

Namespace for named data streams