[src/trunk]: src/sys/rump/librump/rumpuser Improve host file size detection f...

[pooka <pooka%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1d903377861e
branches:  trunk
changeset: 749152:1d903377861e
user:      pooka <pooka%NetBSD.org@localhost>
date:      Thu Nov 19 13:25:48 2009 +0000

description:
Improve host file size detection for devices (i.e. make it work).
Use ioctl() on NetBSD since it appears to be the only way to get
the info.  On other platforms, attempt lseek() and if that doesn't
work, punt, and hope someone comes along with a better implementation
later.

diffstat:

 sys/rump/librump/rumpuser/rumpuser.c |  79 ++++++++++++++++++++++++++++++++---
 1 files changed, 71 insertions(+), 8 deletions(-)

diffs (127 lines):

diff -r 86480254afc1 -r 1d903377861e sys/rump/librump/rumpuser/rumpuser.c
--- a/sys/rump/librump/rumpuser/rumpuser.c      Thu Nov 19 06:48:37 2009 +0000
+++ b/sys/rump/librump/rumpuser/rumpuser.c      Thu Nov 19 13:25:48 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rumpuser.c,v 1.44 2009/10/24 11:29:55 pooka Exp $      */
+/*     $NetBSD: rumpuser.c,v 1.45 2009/11/19 13:25:48 pooka Exp $      */
 
 /*
  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
@@ -30,7 +30,7 @@
 
 #include <sys/cdefs.h>
 #if !defined(lint)
-__RCSID("$NetBSD: rumpuser.c,v 1.44 2009/10/24 11:29:55 pooka Exp $");
+__RCSID("$NetBSD: rumpuser.c,v 1.45 2009/11/19 13:25:48 pooka Exp $");
 #endif /* !lint */
 
 /* thank the maker for this */
@@ -47,6 +47,10 @@
 #include <sys/mman.h>
 #include <sys/uio.h>
 
+#ifdef __NetBSD__
+#include <sys/disklabel.h>
+#endif
+
 #include <assert.h>
 #include <err.h>
 #include <errno.h>
@@ -68,15 +72,13 @@
 rumpuser_getfileinfo(const char *path, uint64_t *size, int *ft, int *error)
 {
        struct stat sb;
-       int rv;
+       int needsdev = 0;
 
-       rv = stat(path, &sb);
-       if (rv == -1) {
+       if (stat(path, &sb) == -1) {
                *error = errno;
-               return rv;
+               return -1;
        }
 
-       *size = sb.st_size;
        switch (sb.st_mode & S_IFMT) {
        case S_IFDIR:
                *ft = RUMPUSER_FT_DIR;
@@ -86,16 +88,77 @@
                break;
        case S_IFBLK:
                *ft = RUMPUSER_FT_BLK;
+               needsdev = 1;
                break;
        case S_IFCHR:
                *ft = RUMPUSER_FT_CHR;
+               needsdev = 1;
                break;
        default:
                *ft = RUMPUSER_FT_OTHER;
                break;
        }
 
-       return rv;
+       if (!needsdev) {
+               *size = sb.st_size;
+       } else {
+               /*
+                * Welcome to the jungle.  Of course querying the kernel
+                * for a device partition size is supposed to be far from
+                * trivial.  On NetBSD we use ioctl.  On $other platform
+                * we have a problem.  We try "the lseek trick" and just
+                * fail if that fails.  Platform specific code can later
+                * be written here if appropriate.
+                *
+                * On NetBSD we hope and pray that for block devices nobody
+                * else is holding them open, because otherwise the kernel
+                * will not permit us to open it.  Thankfully, this is
+                * usually called only in bootstrap and then we can
+                * forget about it.
+                */
+#ifndef __NetBSD__
+               off_t off;
+               int fd;
+
+               fd = open(path, O_RDONLY);
+               if (fd == -1) {
+                       *error = errno;
+                       return -1;
+               }
+
+               off = lseek(fd, 0, SEEK_END);
+               close(fd);
+               if (off != 0) {
+                       *size = off;
+                       return 0;
+               }
+               fprintf(stderr, "error: device size query not implemented on "
+                   "this platform\n");
+               *error = EOPNOTSUPP;
+               return -1;
+#else
+               struct disklabel lab;
+               struct partition *parta;
+               int fd;
+
+               fd = open(path, O_RDONLY);
+               if (fd == -1) {
+                       *error = errno;
+                       return -1;
+               }
+
+               if (ioctl(fd, DIOCGDINFO, &lab) == -1) {
+                       *error = errno;
+                       return -1;
+               }
+               close(fd);
+
+               parta = &lab.d_partitions[DISKPART(sb.st_dev)];
+               *size = lab.d_secsize * parta->p_size;
+#endif /* __NetBSD__ */
+       }
+
+       return 0;
 }
 
 int