Release 4.11 fs/fs_struct.c

#include <linux/export.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/fs.h>
#include <linux/path.h>
#include <linux/slab.h>
#include <linux/fs_struct.h>
#include "internal.h"

/*
 * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
 * It can block.
 */


void set_fs_root(struct fs_struct *fs, const struct path *path)
{
	struct path old_root;

	path_get(path);
	spin_lock(&fs->lock);
	write_seqcount_begin(&fs->seq);
	old_root = fs->root;
	fs->root = *path;
	write_seqcount_end(&fs->seq);
	spin_unlock(&fs->lock);
	if (old_root.dentry)
		path_put(&old_root);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
64
78.05%
4
66.67%
Nicholas Piggin
18
21.95%
2
33.33%
Total
82
100.00%
6
100.00%

/*
 * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
 * It can block.
 */


void set_fs_pwd(struct fs_struct *fs, const struct path *path)
{
	struct path old_pwd;

	path_get(path);
	spin_lock(&fs->lock);
	write_seqcount_begin(&fs->seq);
	old_pwd = fs->pwd;
	fs->pwd = *path;
	write_seqcount_end(&fs->seq);
	spin_unlock(&fs->lock);

	if (old_pwd.dentry)
		path_put(&old_pwd);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
64
78.05%
4
66.67%
Nicholas Piggin
18
21.95%
2
33.33%
Total
82
100.00%
6
100.00%



static inline int replace_path(struct path *p, const struct path *old, const struct path *new)
{
	if (likely(p->dentry != old->dentry || p->mnt != old->mnt))
		return 0;
	*p = *new;
	return 1;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
57
100.00%
1
100.00%
Total
57
100.00%
1
100.00%



void chroot_fs_refs(const struct path *old_root, const struct path *new_root)
{
	struct task_struct *g, *p;
	struct fs_struct *fs;
	int count = 0;

	read_lock(&tasklist_lock);
	do_each_thread(g, p) {
		task_lock(p);
		fs = p->fs;
		if (fs) {
			int hits = 0;
			spin_lock(&fs->lock);
			write_seqcount_begin(&fs->seq);
			hits += replace_path(&fs->root, old_root, new_root);
			hits += replace_path(&fs->pwd, old_root, new_root);
			write_seqcount_end(&fs->seq);
			while (hits--) {
				count++;
				path_get(new_root);
			}
			spin_unlock(&fs->lock);
		}
		task_unlock(p);
	} while_each_thread(g, p);
	read_unlock(&tasklist_lock);
	while (count--)
		path_put(old_root);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
161
92.53%
4
66.67%
Nicholas Piggin
13
7.47%
2
33.33%
Total
174
100.00%
6
100.00%



void free_fs_struct(struct fs_struct *fs)
{
	path_put(&fs->root);
	path_put(&fs->pwd);
	kmem_cache_free(fs_cachep, fs);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
33
100.00%
3
100.00%
Total
33
100.00%
3
100.00%



void exit_fs(struct task_struct *tsk)
{
	struct fs_struct *fs = tsk->fs;

	if (fs) {
		int kill;
		task_lock(tsk);
		spin_lock(&fs->lock);
		tsk->fs = NULL;
		kill = !--fs->users;
		spin_unlock(&fs->lock);
		task_unlock(tsk);
		if (kill)
			free_fs_struct(fs);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
75
97.40%
2
66.67%
Nicholas Piggin
2
2.60%
1
33.33%
Total
77
100.00%
3
100.00%



struct fs_struct *copy_fs_struct(struct fs_struct *old)
{
	struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
	/* We don't need to lock fs - think why ;-) */
	if (fs) {
		fs->users = 1;
		fs->in_exec = 0;
		spin_lock_init(&fs->lock);
		seqcount_init(&fs->seq);
		fs->umask = old->umask;

		spin_lock(&old->lock);
		fs->root = old->root;
		path_get(&fs->root);
		fs->pwd = old->pwd;
		path_get(&fs->pwd);
		spin_unlock(&old->lock);
	}
	return fs;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
74
62.71%
3
42.86%
Nicholas Piggin
43
36.44%
3
42.86%
Miklos Szeredi
1
0.85%
1
14.29%
Total
118
100.00%
7
100.00%



int unshare_fs_struct(void)
{
	struct fs_struct *fs = current->fs;
	struct fs_struct *new_fs = copy_fs_struct(fs);
	int kill;

	if (!new_fs)
		return -ENOMEM;

	task_lock(current);
	spin_lock(&fs->lock);
	kill = !--fs->users;
	current->fs = new_fs;
	spin_unlock(&fs->lock);
	task_unlock(current);

	if (kill)
		free_fs_struct(fs);

	return 0;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
88
97.78%
2
66.67%
Nicholas Piggin
2
2.22%
1
33.33%
Total
90
100.00%
3
100.00%


EXPORT_SYMBOL_GPL(unshare_fs_struct);



int current_umask(void)
{
	return current->fs->umask;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
14
100.00%
1
100.00%
Total
14
100.00%
1
100.00%


EXPORT_SYMBOL(current_umask);

/* to be mentioned only in INIT_TASK */

struct fs_struct init_fs = {
	.users		= 1,
	.lock		= __SPIN_LOCK_UNLOCKED(init_fs.lock),
	.seq		= SEQCNT_ZERO(init_fs.seq),
	.umask		= 0022,
};
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
687
85.88%
8
50.00%
Nicholas Piggin
102
12.75%
3
18.75%
John Stultz
5
0.62%
1
6.25%
Ingo Molnar
4
0.50%
2
12.50%
Miklos Szeredi
1
0.12%
1
6.25%
Paul Gortmaker
1
0.12%
1
6.25%
Total
800
100.00%
16
100.00%
Directory: fs

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.