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Unrot uml mconsole a bit

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2009-12-24 00:44:44 -05:00
parent 7b264fc2be
commit 4ecf09fd3a
1 changed files with 20 additions and 33 deletions
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53
arch/um/drivers/mconsole_kern.c
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@ -125,50 +125,36 @@ void mconsole_log(struct mc_request *req)
void mconsole_proc(struct mc_request *req)
{
struct nameidata nd;
struct file_system_type *proc;
struct super_block *super;
struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
struct file *file;
int n, err;
char *ptr = req->request.data, *buf;
mm_segment_t old_fs = get_fs();
ptr += strlen("proc");
ptr = skip_spaces(ptr);
proc = get_fs_type("proc");
if (proc == NULL) {
mconsole_reply(req, "procfs not registered", 1, 0);
goto out;
}
super = (*proc->get_sb)(proc, 0, NULL, NULL);
put_filesystem(proc);
if (super == NULL) {
mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
goto out;
}
up_write(&super->s_umount);
nd.path.dentry = super->s_root;
nd.path.mnt = NULL;
nd.flags = O_RDONLY + 1;
nd.last_type = LAST_ROOT;
/* START: it was experienced that the stability problems are closed
* if commenting out these two calls + the below read cycle. To
* make UML crash again, it was enough to readd either one.*/
err = link_path_walk(ptr, &nd);
err = vfs_path_lookup(mnt->mnt_root, mnt, ptr, LOOKUP_FOLLOW, &nd);
if (err) {
mconsole_reply(req, "Failed to look up file", 1, 0);
goto out_kill;
goto out;
}
err = may_open(&nd.path, MAY_READ, FMODE_READ);
if (result) {
mconsole_reply(req, "Failed to open file", 1, 0);
path_put(&nd.path);
goto out;
}
file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
current_cred());
err = PTR_ERR(file);
if (IS_ERR(file)) {
mconsole_reply(req, "Failed to open file", 1, 0);
goto out_kill;
path_put(&nd.path);
goto out;
}
/*END*/
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (buf == NULL) {
@ -176,10 +162,13 @@ void mconsole_proc(struct mc_request *req)
goto out_fput;
}
if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
if (file->f_op->read) {
do {
n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
&file->f_pos);
loff_t pos;
set_fs(KERNEL_DS);
n = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
file_pos_write(file, pos);
set_fs(old_fs);
if (n >= 0) {
buf[n] = '\0';
mconsole_reply(req, buf, 0, (n > 0));
@ -197,8 +186,6 @@ void mconsole_proc(struct mc_request *req)
kfree(buf);
out_fput:
fput(file);
out_kill:
deactivate_super(super);
out: ;
}
#endif