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| Volume Management Library Functions | media_findname(3VOLMGT) |
| | media_findname - convert a supplied name into an absolute pathname that can be used to access removable media |
SYNOPSIS
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cc [ flag ... ] file ... -lvolmgt [ library ... ]
#include <volmgt.h>
char *media_findname(char *start); |
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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:
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/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).
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/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.
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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.
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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.
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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.
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Upon successful completion media_findname() returns a pointer to the pathname found. In the case of an error a null pointer is returned.
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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:
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ENXIO
- The specified absolute pathname was not a character special device, and it was not a directory
with a character special device in it.
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| | Example 1. Sample programs of the media_findname function.
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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).
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(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");
}
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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.
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if ((nm = media_findname("floppy0")) != NULL) {
(void) printf("path to floppy0 is \"%s\"\n", nm);
} else {
(void) printf("nothing in floppy0\n");
}
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See attributes(5) for descriptions of the following
attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | MT-Unsafe |
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cc(1B), fdformat(1), vold(1M), lstat(2), readlink(2), stat(2), free(3C), malloc(3C), volmgt_check(3VOLMGT), volmgt_inuse(3VOLMGT), volmgt_root(3VOLMGT), volmgt_running(3VOLMGT), volmgt_symname(3VOLMGT), attributes(5), volfs(7FS)
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If media_findname() cannot find a match for the supplied name, it performs a volmgt_check(3VOLMGT) 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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