/*
* Object creation/destruction.
*/
LinuxSystemRoot* newLinuxSystemRoot(void)
{
LinuxSystemRoot* object;
unsigned m_seq = 0;
object = talpa_alloc(sizeof(template_LinuxSystemRoot));
if ( object )
{
struct task_struct* inittask;
memcpy(object, &template_LinuxSystemRoot, sizeof(template_LinuxSystemRoot));
object->i_ISystemRoot.object = object;
talpa_tasklist_lock();
inittask = talpa_find_task_by_pid(1);
talpa_tasklist_unlock();
if ( inittask )
{
struct fs_struct *init_fs;
struct vfsmount *rootmnt;
task_lock(inittask);
init_fs = inittask->fs;
if ( init_fs )
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30)
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
spin_lock(&init_fs->lock);
#else
write_lock(&init_fs->lock);
#endif
init_fs->users++;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
spin_unlock(&init_fs->lock);
#else
write_unlock(&init_fs->lock);
#endif
#else
atomic_inc(&init_fs->count);
#endif
}
task_unlock(inittask);
if ( init_fs )
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
spin_lock(&init_fs->lock);
#else
write_lock(&init_fs->lock);
#endif
restart_mnt:
talpa_vfsmount_lock(&m_seq); // locks dcache_lock on 2.4
for (rootmnt = talpa_fs_mnt(init_fs); rootmnt != getParent(rootmnt); rootmnt = getParent(rootmnt));
object->mMnt = mntget(rootmnt);
object->mDentry = dget(rootmnt->mnt_root);
if (talpa_vfsmount_unlock(&m_seq)) // unlocks dcache_lock on 2.4
{
goto restart_mnt;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30)
init_fs->users--;
#else
atomic_dec(&init_fs->count);
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
spin_unlock(&init_fs->lock);
#else
write_unlock(&init_fs->lock);
#endif
}
}
if ( !object->mMnt || !object->mDentry )
{
if ( object->mMnt )
{
mntput(object->mMnt);
}
if ( object->mDentry )
{
dput(object->mDentry);
}
talpa_free(object);
return NULL;
}
}
return object;
}
/**
* d_path - return the path of a dentry
* @dentry: dentry to report
* @vfsmnt: vfsmnt to which the dentry belongs
* @root: root dentry
* @rootmnt: vfsmnt to which the root dentry belongs
* @buffer: buffer to return value in
* @buflen: buffer length
*
* Convert a dentry into an ASCII path name. If the entry has been deleted
* the string " (deleted)" is appended. Note that this is ambiguous.
*
* Returns the buffer or an error code if the path was too long.
*
* "buflen" should be positive. Caller holds the dcache_lock.
*/
static char * __talpa_d_path( struct dentry *dentry, struct vfsmount *vfsmnt,
struct dentry *root, struct vfsmount *rootmnt,
char *buffer, int buflen)
{
char * end = buffer+buflen;
char * retval;
int namelen;
unsigned m_seq = 1;
*--end = '\0';
buflen--;
if (!IS_ROOT(dentry) && d_unhashed(dentry))
{
buflen -= 10;
end -= 10;
if (buflen < 0)
goto Elong;
memcpy(end, " (deleted)", 10);
}
if (buflen < 1)
goto Elong;
/* Get '/' right */
retval = end-1;
*retval = '/';
for (;;) {
struct dentry * parent;
if (dentry == root && vfsmnt == rootmnt)
break;
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry))
{
/* Global root? */
talpa_vfsmount_lock(&m_seq);
if (vfsmnt->mnt_parent == vfsmnt) {
talpa_vfsmount_unlock(&m_seq);
goto global_root;
}
dentry = vfsmnt->mnt_mountpoint;
vfsmnt = vfsmnt->mnt_parent;
talpa_vfsmount_unlock(&m_seq);
continue;
}
parent = dentry->d_parent;
prefetch(parent);
namelen = dentry->d_name.len;
buflen -= namelen + 1;
if (buflen < 0)
goto Elong;
end -= namelen;
memcpy(end, dentry->d_name.name, namelen);
*--end = '/';
retval = end;
dentry = parent;
}
return retval;
global_root:
namelen = dentry->d_name.len;
buflen -= namelen;
if (buflen < 0)
goto Elong;
retval -= namelen-1; /* hit the slash */
memcpy(retval, dentry->d_name.name, namelen);
return retval;
Elong:
return ERR_PTR(-ENAMETOOLONG);
}
/**
* We iterate all the possible parents of our mount point,
* and see if they also have a mount on the same mount point.
*/
int countPropagationPoints(struct vfsmount* vmnt)
{
#ifdef TALPA_SHARED_MOUNTS
talpa_mount_struct *mnt = real_mount(vmnt);
talpa_mount_struct *parent = mnt->mnt_parent;
talpa_mount_struct *child = NULL;
talpa_mount_struct *m;
int ret = 1;
unsigned m_seq = 1;
#ifdef DEBUG_PROPAGATION_POINTS
talpa_mnt_namespace_t* ns;
size_t path_size = 0;
char* path = talpa_alloc_path_atomic(&path_size);
const char* p = absolutePath(mnt->mnt_mountpoint,vfs_mount(parent), path, path_size);
if (unlikely( path == NULL ))
{
warn("talpa_alloc_path failed");
return 0;
}
ns = mnt->mnt_ns;
dbg("PATH START: %s ns=%p ns.ns.inum=%u",p,ns,PROC_INUM_FROM_MNT_NAMESPACE(ns));
ns = parent->mnt_ns;
p = absolutePath(parent->mnt_mountpoint,vfs_mount(parent->mnt_parent), path, path_size);
dbg("PARENT: %s ns=%p ns.ns.inum=%u",p,ns,PROC_INUM_FROM_MNT_NAMESPACE(ns));
#endif /* DEBUG_PROPAGATION_POINTS */
talpa_vfsmount_lock(&m_seq); /* locks dcache_lock on 2.4 */
/**
* Iterate all possible shared/slave destination parents for copies of vmnt
*/
for (m = propagation_next(parent, parent); m;
m = propagation_next(m, parent))
{
child = talpa_lookup_mnt_last(vfs_mount(m), mnt->mnt_mountpoint);
if (child)
{
#ifdef DEBUG_PROPAGATION_POINTS
/* absolutePath() locks up in d_path() if vfsmount_lock is already held */
p = child->mnt_mountpoint->d_name.name;
ns = child->mnt_ns;
dbg("CHILD: %s ns=%p ns.ns.inum=%u",p,ns,PROC_INUM_FROM_MNT_NAMESPACE(ns));
#endif /* DEBUG_PROPAGATION_POINTS */
if (list_empty(&child->mnt_mounts))
{
ret += 1;
}
}
}
talpa_vfsmount_unlock(&m_seq); /* unlocks dcache_lock on 2.4 */
#ifdef DEBUG_PROPAGATION_POINTS
talpa_free_path(path);
#endif
return ret;
#else /* ! TALPA_SHARED_MOUNTS */
return 1;
#endif /* TALPA_SHARED_MOUNTS */
}
char* talpa__d_namespace_path( struct dentry *dentry, struct vfsmount *vfsmnt,
struct dentry *root, struct vfsmount *rootmnt,
char *buffer, int buflen, bool* nonRootNamespaceOut, bool* inProcessNamespaceOut)
{
char* path;
#ifdef TALPA_MNT_NAMESPACE
struct vfsmount *ns_root_mnt = NULL;
struct dentry *ns_root_dentry;
unsigned m_seq = 1;
struct vfsmount *process_root_mnt;
struct dentry *process_root_dentry;
struct task_struct* proc;
proc = current;
if ( likely(proc->fs != NULL) )
{
talpa_proc_fs_lock(&proc->fs->lock);
process_root_mnt = mntget(talpa_task_root_mnt(proc));
process_root_dentry = dget(talpa_task_root_dentry(proc));
talpa_proc_fs_unlock(&proc->fs->lock);
if (inProcessNamespaceOut)
{
if ( likely( proc->nsproxy != NULL ) )
{
*inProcessNamespaceOut = (getNamespaceInfo(vfsmnt) == proc->nsproxy->mnt_ns);
}
else
{
*inProcessNamespaceOut = false;
}
}
talpa_vfsmount_lock(&m_seq);
if (getNamespaceInfo(process_root_mnt))
{
ns_root_mnt = mntget(getNamespaceRoot(process_root_mnt));
}
talpa_vfsmount_unlock(&m_seq);
dbg("root dentry %s dentry=%p vfsmnt=%p",process_root_dentry->d_name.name,process_root_dentry,process_root_mnt);
if(ns_root_mnt)
{
ns_root_dentry = dget(ns_root_mnt->mnt_root);
dbg("ns_root_dentry %s dentry=%p vfsmnt=%p",ns_root_dentry->d_name.name,ns_root_dentry,ns_root_mnt);
path = talpa__d_path(dentry, vfsmnt, ns_root_dentry, ns_root_mnt,
buffer, buflen, NULL);
dbg("talpa__d_namespace_path: found d_namespace_path: %s", path);
if (nonRootNamespaceOut)
{
*nonRootNamespaceOut = (ns_root_mnt != rootmnt);
}
dput(ns_root_dentry);
mntput(ns_root_mnt);
}
else
{
path = talpa__d_path(dentry, vfsmnt, process_root_dentry, process_root_mnt,
buffer, buflen, nonRootNamespaceOut);
dbg("talpa__d_namespace_path: found non namespace path: %s", path);
}
dput(process_root_dentry);
mntput(process_root_mnt);
}
else
{
dbg("proc->fs == NULL, cannot get namespace path");
if (inProcessNamespaceOut)
{
*inProcessNamespaceOut = false;
}
#else /* !TALPA_MNT_NAMESPACE */
{
if (inProcessNamespaceOut)
{
*inProcessNamespaceOut = true;
}
#endif
path = talpa__d_path(dentry, vfsmnt, root, rootmnt,
buffer, buflen, nonRootNamespaceOut);
dbg("talpa__d_namespace_path: found non namespace path: %s", path);
}
return path;
}
#ifdef TALPA_MNT_NAMESPACE
static void debugPathWalk( struct dentry *dentry, struct vfsmount *vfsmnt,
struct dentry *root, struct vfsmount *rootmnt)
{
/* Debug - try and evaluate roots */
int count = 50;
struct dentry *td = dentry;
struct vfsmount *temp_vfsmnt = vfsmnt;
err("DEBUG: expected root node %s dentry=%p vfsmnt=%p",root->d_name.name,root,rootmnt);
while (td != root || temp_vfsmnt != rootmnt)
{
count--;
if (count == 0)
{
err("DEBUG: reached count limit!");
break;
}
err("DEBUG: examining %s %p",td->d_name.name,td);
if (td == temp_vfsmnt->mnt_root || IS_ROOT(td))
{
struct vfsmount *temp2_vfsmnt = getParent(temp_vfsmnt);
if (td == temp_vfsmnt->mnt_root)
{
err("DEBUG: found root dentry td == temp_vfsmnt->mnt_root %p",td);
}
if (IS_ROOT(td))
{
err("DEBUG: found root dentry IS_ROOT(td) %p",td);
}
err("DEBUG: going to parent: %p -> %p",temp_vfsmnt,temp2_vfsmnt);
if (temp_vfsmnt != temp2_vfsmnt)
{
td = getVfsMountPoint(temp_vfsmnt);
err("DEBUG: going to mountpoint %s dentry=%p", td->d_name.name, td);
temp_vfsmnt = temp2_vfsmnt;
}
else
{
err("DEBUG: Got to temp_vfsmnt = temp2_vfsmnt!");
}
}
if (td == td->d_parent)
{
err("DEBUG: td == td->d_parent");
break;
}
else if (td->d_parent == NULL)
{
err("DEBUG: td->d_parent == NULL");
break;
}
td = td->d_parent;
}
err("DEBUG: actual root node %s dentry=%p vfsmnt=%p",td->d_name.name,td,temp_vfsmnt);
if (td == root && temp_vfsmnt == rootmnt)
{
err("DEBUG: Found the correct root");
}
else
{
err("DEBUG: Found wrong root td=%p (name=%s) vfsmnt=%p",
td,
td->d_name.name,
temp_vfsmnt);
err("DEBUG: Expected root=%p (name=%s) vfsmnt=%p",
root,
root->d_name.name,
rootmnt);
}
}
int iterateFilesystems(struct vfsmount* root, int (*callback) (struct vfsmount* mnt, unsigned long flags, bool fromMount))
{
talpa_mount_struct *mnt, *nextmnt, *prevmnt;
struct list_head *nexthead = NULL;
int ret;
unsigned m_seq = 1;
mnt = real_mount(root);
talpa_mntget(mnt); /* Take extra reference count for the loop */
do
{
struct vfsmount* vfsmnt = vfs_mount(mnt);
dbg("VFSMNT: 0x%p (at 0x%p), sb: 0x%p, dev: %s, flags: 0x%lx, fs: %s", mnt, mnt->mnt_parent,
vfsmnt->mnt_sb, mnt->mnt_devname, vfsmnt->mnt_sb->s_flags, vfsmnt->mnt_sb->s_type->name);
ret = callback(vfsmnt, vfsmnt->mnt_sb->s_flags, false);
if (ret)
{
break;
}
talpa_vfsmount_lock(&m_seq); /* locks dcache_lock on 2.4 */
/* Go down the tree for a child if there is one */
if ( !list_empty(&mnt->mnt_mounts) )
{
nextmnt = list_entry(mnt->mnt_mounts.next, talpa_mount_struct, mnt_child);
}
else
{
nextmnt = mnt;
/* If no children, go up until we found some. Abort on root. */
while ( nextmnt != nextmnt->mnt_parent )
{
nexthead = nextmnt->mnt_child.next;
/* Take next child if available */
if ( nexthead != &nextmnt->mnt_parent->mnt_mounts )
{
break;
}
/* Otherwise go up the tree */
nextmnt = nextmnt->mnt_parent;
}
/* Abort if we are at the root */
if ( nextmnt == nextmnt->mnt_parent )
{
talpa_vfsmount_unlock(&m_seq); /* unlocks dcache_lock on 2.4 */
talpa_mntput(mnt);
break;
}
/* Take next mount from the list */
nextmnt = list_entry(nexthead, talpa_mount_struct, mnt_child);
}
talpa_mntget(nextmnt);
prevmnt = mnt;
mnt = nextmnt;
talpa_vfsmount_unlock(&m_seq); /* unlocks dcache_lock on 2.4 */
talpa_mntput(prevmnt);
} while (mnt);
/* Don't mntput root as we didn't take a reference for ourselves */
return ret;
}
