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Introduce ukfs_vfstypes() which returns the available file system

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types loaded into rump.  Now it is possible to iterate over all
file system types supported by a rump program in an attempt to
access an unknown file system image instead of having to know
beforehand which type of file system is on the image.
This commit is contained in:
pooka 2008-08-01 19:52:10 +00:00
parent 0b5af21c5a
commit 541195ef5d
3 changed files with 65 additions and 3 deletions
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20
lib/libukfs/ukfs.3
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@ -1,4 +1,4 @@
.\" $NetBSD: ukfs.3,v 1.2 2008/08/01 14:47:28 pooka Exp $
.\" $NetBSD: ukfs.3,v 1.3 2008/08/01 19:52:10 pooka Exp $
.\"
.\" Copyright (c) 2008 Antti Kantee. All rights reserved.
.\"
@ -74,6 +74,10 @@ which should be released after use.
.br
.Fn ukfs_modload_dir "const char *dirname"
.Pp
.Ft ssize_t
.br
.Fn ukfs_vfstypes "char *buf, size_t buflen"
.Pp
.Ft struct ukfs *
.br
.Fo ukfs_mount
@ -127,6 +131,20 @@ not just a specific instance of
It is preferable to call them from only one thread, as the underlying
dynamic library interfaces may not be threadsafe.
.Pp
.Fn ukfs_vfstypes
queries the available file system types and returns a nul-terminated
list of types separated by spaces in
.Fa buf .
The format of the list is equivalent to the one returned by
.Xr sysctl 3
on the name
.Pa vfs.generic.fstypes .
The function returns the length of the string without the trailing nul
or \-1 for error.
Notably, the return value 0 means there are no file systems available.
If there is not enough room in the caller's buffer for all file system
types, as many as fit will be returned.
.Pp
.Fn ukfs_mount
intializes a file system image.
The handle resulting from the operation is passed to all other routines

45
lib/libukfs/ukfs.c
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@ -1,4 +1,4 @@
/* $NetBSD: ukfs.c,v 1.3 2008/08/01 14:47:28 pooka Exp $ */
/* $NetBSD: ukfs.c,v 1.4 2008/08/01 19:52:10 pooka Exp $ */
/*
* Copyright (c) 2007, 2008 Antti Kantee. All Rights Reserved.
@ -42,6 +42,8 @@
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/mount.h>
#include <assert.h>
#include <dirent.h>
@ -656,6 +658,47 @@ ukfs_modload_dir(const char *dir)
return nloaded;
}
/* XXX: this code uses definitions from NetBSD, needs rumpdefs */
ssize_t
ukfs_vfstypes(char *buf, size_t buflen)
{
int mib[3];
struct sysctlnode q, ans[128];
size_t alen;
int error, i;
mib[0] = CTL_VFS;
mib[1] = VFS_GENERIC;
mib[2] = CTL_QUERY;
alen = sizeof(ans);
memset(&q, 0, sizeof(q));
q.sysctl_flags = SYSCTL_VERSION;
if (rump_sys___sysctl(mib, 3, ans, &alen, &q, sizeof(q), &error) == -1){
errno = error;
return -1;
}
for (i = 0; i < alen/sizeof(ans[0]); i++)
if (strcmp("fstypes", ans[i].sysctl_name) == 0)
break;
if (i == alen/sizeof(ans[0])) {
errno = ENXIO;
return -1;
}
mib[0] = CTL_VFS;
mib[1] = VFS_GENERIC;
mib[2] = ans[i].sysctl_num;
if (rump_sys___sysctl(mib, 3, buf, &buflen, NULL, 0, &error) == -1) {
errno = error;
return -1;
}
return buflen;
}
/*
* Utilities

3
lib/libukfs/ukfs.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: ukfs.h,v 1.5 2008/08/01 14:50:28 pooka Exp $ */
/* $NetBSD: ukfs.h,v 1.6 2008/08/01 19:52:11 pooka Exp $ */
/*
* Copyright (c) 2007, 2008 Antti Kantee. All Rights Reserved.
@ -95,6 +95,7 @@ struct vnode *ukfs_getrvp(struct ukfs *);
/* dynamic loading of library modules */
int ukfs_modload(const char *);
int ukfs_modload_dir(const char *);
ssize_t ukfs_vfstypes(char *, size_t);
/* Utilities */
int ukfs_util_builddirs(struct ukfs *, const char *, mode_t);