media_findname(3X) manual page
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media_findname - convert a supplied name into an absolute pathname
that can be used to access removable media
cc [ flag... ] file... -lvolmgt
[ library.... ]
#include <volmgt.h>
char *media_findname(char *start);
MT-Unsafe
media_findname() converts the supplied start string into an
absolute pathname that can then be used to access a particular piece of
media.
The start parameter can be one of the following types of specifications:
- /dev/...
- An absolute pathname in /dev, such as /dev/rdiskette0, in which case
a copy of that string is returned (see NOTES on this page).
- /vol/...
- An absolute
Volume Management pathname, such as /vol/dev/aliases/floppy0 or /vol/dsk/fred.
If this supplied pathname is not a symbolic link, then a copy of that pathname
is returned. If the supplied pathname is a symbolic link then it is dereferenced
and a copy of that dereferenced pathname is returned.
- volume_name
- The Volume
Management volume name for a particular volume, such as fred (see fdformat(1)
for a description of how to label floppies). In this case a pathname in
the Volume Management namespace is returned.
- volmgt_symname
- The Volume Management
symbolic name for a device, such as floppy0 or cdrom2 (see volfs(7FS)
for
more information on Volume Management symbolic names), in which case a
pathname in the Volume Management namespace is returned.
- media_type
- The
Volume Management generic media type name. For example, floppy or cdrom.
In this case media_findname() looks for the first piece of media that matches
that media type, starting at 0 (zero) and continuing on until a match is
found (or some fairly large maximum number is reached). In this case, if
a match is found, a copy of the pathname to the volume found is returned.
Upon successful completion media_findname() returns a pointer
to the pathname found. In the case of an error a null pointer is returned.
For cases where the supplied start parameter is an absolute pathname,
media_findname() can fail, returning a null string pointer, if an lstat(2)
of that supplied pathname fails. Also, if the supplied absolute pathname
is a symbolic link, media_findname() can fail if a readlink(2)
of that
symbolic link fails, or if a stat(2)
of the pathname pointed to by that
symbolic link fails, or if any of the following is true:
- ENXIO
- The specified
absolute pathname was not a character special device, and it was not a
directory with a character special device in it.
The following example
attempts to find what the Volume Management pathname is to a piece of media
called fred. Notice that a volmgt_check() is done first (see the NOTES
section on this page).
(void) volmgt_check(NULL);
if ((nm = media_findname("fred")) != NULL) {
(void) printf("media named \"fred\" is at \"%s\"\n", nm);
} else {
(void) printf("media named \"fred\" not found\n");
}
This example looks for whatever volume is in the first floppy drive, letting
media_findname() call volmgt_check() if and only if no floppy is currently
known to be the first floppy drive.
if ((nm = media_findname("floppy0")) != NULL) {
(void) printf("path to floppy0 is \"%s\"\n", nm);
} else {
(void) printf("nothing in floppy0\n");
}
cc(1B)
, fdformat(1)
, vold(1M)
, lstat(2)
, readlink(2)
, stat(2)
,
free(3C)
, malloc(3C)
, volmgt_check(3X)
, volmgt_inuse(3X)
, volmgt_root(3X)
,
volmgt_running(3X)
, volmgt_symname(3X)
, volfs(7FS)
If media_findname()
cannot find a match for the supplied name, it performs a volmgt_check(3X)
and tries again, so it can be more efficient to perform volmgt_check()
before calling media_findname().
Upon success media_findname() returns
a pointer to string which has been allocated; this should be freed when
no longer in use (see free(3C)
).
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