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authorChristoph Hellwig <hch@lst.de>2008-11-28 10:09:09 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2009-03-27 14:43:57 -0400
commit2b1c6bd77d4e6a727ffac8630cd154b2144b751a (patch)
treeffc4237dbeed66492124ef2ccecf48db0767531a /fs
parentec1ab0abde0af586a59541ad71841f022dcac3e7 (diff)
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generic compat_sys_ustat
Due to a different size of ino_t ustat needs a compat handler, but currently only x86 and mips provide one. Add a generic compat_sys_ustat and switch all architectures over to it. Instead of doing various user copy hacks compat_sys_ustat just reimplements sys_ustat as it's trivial. This was suggested by Arnd Bergmann. Found by Eric Sandeen when running xfstests/017 on ppc64, which causes stack smashing warnings on RHEL/Fedora due to the too large amount of data writen by the syscall. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/compat.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/fs/compat.c b/fs/compat.c
index d0145ca2757..4e0db94b535 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -378,6 +378,34 @@ out:
return error;
}
+/*
+ * This is a copy of sys_ustat, just dealing with a structure layout.
+ * Given how simple this syscall is that apporach is more maintainable
+ * than the various conversion hacks.
+ */
+asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u)
+{
+ struct super_block *sb;
+ struct compat_ustat tmp;
+ struct kstatfs sbuf;
+ int err;
+
+ sb = user_get_super(new_decode_dev(dev));
+ if (!sb)
+ return -EINVAL;
+ err = vfs_statfs(sb->s_root, &sbuf);
+ drop_super(sb);
+ if (err)
+ return err;
+
+ memset(&tmp, 0, sizeof(struct compat_ustat));
+ tmp.f_tfree = sbuf.f_bfree;
+ tmp.f_tinode = sbuf.f_ffree;
+ if (copy_to_user(u, &tmp, sizeof(struct compat_ustat)))
+ return -EFAULT;
+ return 0;
+}
+
static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
{
if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||