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don't bother with tid_fd_revalidate() in lookups

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what we want it for is actually updating inode metadata;
take _that_ into a separate helper and use it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2018-05-03 09:00:33 -04:00
parent 1ae9bd8b7e
commit 9883638641
1 changed files with 44 additions and 37 deletions
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81
fs/proc/fd.c
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@ -98,12 +98,27 @@ static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode)
return !!file;
}
static void tid_fd_update_inode(struct task_struct *task, struct inode *inode,
fmode_t f_mode)
{
task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
if (S_ISLNK(inode->i_mode)) {
unsigned i_mode = S_IFLNK;
if (f_mode & FMODE_READ)
i_mode |= S_IRUSR | S_IXUSR;
if (f_mode & FMODE_WRITE)
i_mode |= S_IWUSR | S_IXUSR;
inode->i_mode = i_mode;
}
security_task_to_inode(task, inode);
}
static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
{
struct task_struct *task;
struct inode *inode;
unsigned int fd;
fmode_t f_mode;
if (flags & LOOKUP_RCU)
return -ECHILD;
@ -113,18 +128,9 @@ static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
fd = proc_fd(inode);
if (task) {
fmode_t f_mode;
if (tid_fd_mode(task, fd, &f_mode)) {
task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
if (S_ISLNK(inode->i_mode)) {
unsigned i_mode = S_IFLNK;
if (f_mode & FMODE_READ)
i_mode |= S_IRUSR | S_IXUSR;
if (f_mode & FMODE_WRITE)
i_mode |= S_IWUSR | S_IXUSR;
inode->i_mode = i_mode;
}
security_task_to_inode(task, inode);
tid_fd_update_inode(task, inode, f_mode);
put_task_struct(task);
return 1;
}
@ -168,34 +174,35 @@ static int proc_fd_link(struct dentry *dentry, struct path *path)
return ret;
}
struct fd_data {
fmode_t mode;
unsigned fd;
};
static int
proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
struct task_struct *task, const void *ptr)
{
unsigned fd = (unsigned long)ptr;
const struct fd_data *data = ptr;
struct proc_inode *ei;
struct inode *inode;
inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK);
if (!inode)
goto out;
return -ENOENT;
ei = PROC_I(inode);
ei->fd = fd;
ei->fd = data->fd;
inode->i_op = &proc_pid_link_inode_operations;
inode->i_size = 64;
ei->op.proc_get_link = proc_fd_link;
tid_fd_update_inode(task, inode, data->mode);
d_set_d_op(dentry, &tid_fd_dentry_operations);
d_add(dentry, inode);
/* Close the race of the process dying before we return the dentry */
if (tid_fd_revalidate(dentry, 0))
return 0;
out:
return -ENOENT;
return 0;
}
static struct dentry *proc_lookupfd_common(struct inode *dir,
@ -204,17 +211,16 @@ static struct dentry *proc_lookupfd_common(struct inode *dir,
{
struct task_struct *task = get_proc_task(dir);
int result = -ENOENT;
unsigned fd = name_to_int(&dentry->d_name);
fmode_t f_mode;
struct fd_data data = {.fd = name_to_int(&dentry->d_name)};
if (!task)
goto out_no_task;
if (fd == ~0U)
if (data.fd == ~0U)
goto out;
if (!tid_fd_mode(task, fd, &f_mode))
if (!tid_fd_mode(task, data.fd, &data.mode))
goto out;
result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
result = instantiate(dir, dentry, task, &data);
out:
put_task_struct(task);
out_no_task:
@ -241,17 +247,22 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx,
for (fd = ctx->pos - 2;
fd < files_fdtable(files)->max_fds;
fd++, ctx->pos++) {
struct file *f;
struct fd_data data;
char name[10 + 1];
int len;
if (!fcheck_files(files, fd))
f = fcheck_files(files, fd);
if (!f)
continue;
data.mode = f->f_mode;
rcu_read_unlock();
data.fd = fd;
len = snprintf(name, sizeof(name), "%u", fd);
if (!proc_fill_cache(file, ctx,
name, len, instantiate, p,
(void *)(unsigned long)fd))
&data))
goto out_fd_loop;
cond_resched();
rcu_read_lock();
@ -313,27 +324,23 @@ static int
proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
struct task_struct *task, const void *ptr)
{
unsigned fd = (unsigned long)ptr;
const struct fd_data *data = ptr;
struct proc_inode *ei;
struct inode *inode;
inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR);
if (!inode)
goto out;
return -ENOENT;
ei = PROC_I(inode);
ei->fd = fd;
ei->fd = data->fd;
inode->i_fop = &proc_fdinfo_file_operations;
tid_fd_update_inode(task, inode, 0);
d_set_d_op(dentry, &tid_fd_dentry_operations);
d_add(dentry, inode);
/* Close the race of the process dying before we return the dentry */
if (tid_fd_revalidate(dentry, 0))
return 0;
out:
return -ENOENT;
return 0;
}
static struct dentry *