/*      $NetBSD: devnodes.c,v 1.13 2019/06/18 22:34:26 kamil Exp $      */

/*
* Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: devnodes.c,v 1.13 2019/06/18 22:34:26 kamil Exp $");

#include <sys/param.h>
#include <sys/device.h>
#include <sys/filedesc.h>
#include <sys/kmem.h>
#include <sys/lwp.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/vfs_syscalls.h>

#include <rump-sys/vfs.h>

/* realqvik(tm) "devfs" */
static int
makeonedevnode(dev_t devtype, const char *devname,
       devmajor_t majnum, devminor_t minnum)
{
       int error;

       error = do_sys_mknod(curlwp, devname, 0666 | devtype,
           makedev(majnum, minnum), UIO_SYSSPACE);
       if (error == EEXIST) /* XXX: should check it's actually the same */
               error = 0;

       return error;
}

static int
makedevnodes(dev_t devtype, const char *basename, char minchar,
       devmajor_t maj, devminor_t minnum, int nnodes)
{
       int error = 0;
       char *devname, *p;
       size_t devlen;

       devlen = strlen(basename) + 1 + 1; /* +letter +0 */
       devname = kmem_zalloc(devlen, KM_SLEEP);
       strlcpy(devname, basename, devlen);
       p = devname + devlen-2;

       for (; nnodes > 0; nnodes--, minchar++, minnum++) {
               KASSERT(minchar <= 'z');
               *p = minchar;

               if ((error = do_sys_mknod(curlwp, devname, 0666 | devtype,
                   makedev(maj, minnum), UIO_SYSSPACE))) {
                       if (error == EEXIST)
                               error = 0;
                       else
                               goto out;
               }
       }

out:
       kmem_free(devname, devlen);
       return error;
}

static int
makesymlink(const char *dst, const char *src)
{

       return do_sys_symlink(dst, src, UIO_SYSSPACE);
}

enum { NOTEXIST, SAME, DIFFERENT };
static int
doesitexist(const char *path, bool isblk, devmajor_t dmaj, devminor_t dmin)
{
       struct stat sb;
       int error;

       error = do_sys_stat(path, 0, &sb);
       /* even if not ENOENT, we might be able to create it */
       if (error)
               return NOTEXIST;

       if (major(sb.st_rdev) != dmaj || minor(sb.st_rdev) != dmin)
               return DIFFERENT;
       if (isblk && !S_ISBLK(sb.st_mode))
               return DIFFERENT;
       if (!isblk && !S_ISCHR(sb.st_mode))
               return DIFFERENT;

       return SAME;
}

static void
makeonenode(char *buf, size_t len, devmajor_t blk, devmajor_t chr,
   devminor_t dmin, const char *base, int c1, int c2)
{
       char cstr1[2] = {0,0}, cstr2[2] = {0,0};
       int error;

       if (c1 != -1) {
               cstr1[0] = '0' + c1;
               cstr1[1] = '\0';
       }

       if (c2 != -1) {
               cstr2[0] = 'a' + c2;
               cstr2[1] = '\0';

       }

       /* block device */
       snprintf(buf, len, "/dev/%s%s%s", base, cstr1, cstr2);
       if (blk != NODEVMAJOR) {
               switch (doesitexist(buf, true, blk, dmin)) {
               case DIFFERENT:
                       aprint_verbose("mkdevnodes: block device %s "
                           "already exists\n", buf);
                       break;
               case NOTEXIST:
                       if ((error = do_sys_mknod(curlwp, buf, 0600 | S_IFBLK,
                           makedev(blk, dmin), UIO_SYSSPACE)) != 0)
                               aprint_verbose("mkdevnodes: failed to "
                                   "create %s: %d\n", buf, error);
                       break;
               case SAME:
                       /* done */
                       break;
               }
               snprintf(buf, len, "/dev/r%s%s%s", base, cstr1, cstr2);
       }

       switch (doesitexist(buf, true, chr, dmin)) {
       case DIFFERENT:
               aprint_verbose("mkdevnodes: character device %s "
                   "already exists\n", buf);
               break;
       case NOTEXIST:
               if ((error = do_sys_mknod(curlwp, buf, 0600 | S_IFCHR,
                   makedev(chr, dmin), UIO_SYSSPACE)) != 0)
                       aprint_verbose("mkdevnodes: failed to "
                           "create %s: %d\n", buf, error);
               break;
       case SAME:
               /* yeehaa */
               break;
       }
}

void
rump_vfs_builddevs(struct devsw_conv *dcvec, size_t dcvecsize)
{
       char *pnbuf = PNBUF_GET();
       devminor_t themin;
       struct devsw_conv *dc;
       size_t i;
       int v1, v2;

       rump_vfs_makeonedevnode = makeonedevnode;
       rump_vfs_makedevnodes = makedevnodes;
       rump_vfs_makesymlink = makesymlink;

       for (i = 0; i < dcvecsize; i++) {
               dc = &dcvec[i];

               switch (dc->d_class) {
               case DEVNODE_DONTBOTHER:
                       break;
               case DEVNODE_SINGLE:
                       if (dc->d_flags & DEVNODE_FLAG_ISMINOR0) {
                               themin = dc->d_vectdim[0];
                       } else {
                               themin = 0;
                       }
                       makeonenode(pnbuf, MAXPATHLEN,
                           dc->d_bmajor, dc->d_cmajor, themin,
                           dc->d_name, -1, -1);
                       break;
               case DEVNODE_VECTOR:
                       for (v1 = 0; v1 < dc->d_vectdim[0]; v1++) {
                               if (dc->d_vectdim[1] == 0) {
                                       makeonenode(pnbuf, MAXPATHLEN,
                                           dc->d_bmajor, dc->d_cmajor,
                                           v1, dc->d_name, v1, -1);
                               } else {
                                       for (v2 = 0;
                                           v2 < dc->d_vectdim[1]; v2++) {
                                               makeonenode(pnbuf, MAXPATHLEN,
                                                   dc->d_bmajor, dc->d_cmajor,
                                                   v1 * dc->d_vectdim[1] + v2,
                                                   dc->d_name, v1, v2);
                                       }
                               }
                       }

                       /* add some extra sanity checks here */
                       if (dc->d_flags & DEVNODE_FLAG_LINKZERO) {
                               /*
                                * ok, so we cheat a bit since
                                * symlink isn't supported on rumpfs ...
                                */
                               makeonenode(pnbuf, MAXPATHLEN,
                                   -1, dc->d_cmajor, 0, dc->d_name, -1, -1);

                       }
                       break;
               }
       }

       PNBUF_PUT(pnbuf);
}

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