[people/ms/linux.git] / fs / proc / fd.c

#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/dcache.h>
#include <linux/path.h>
#include <linux/fdtable.h>
#include <linux/namei.h>
#include <linux/pid.h>
#include <linux/security.h>
#include <linux/file.h>
#include <linux/seq_file.h>

#include <linux/proc_fs.h>

#include "internal.h"
#include "fd.h"

static int seq_show(struct seq_file *m, void *v)
{
	struct files_struct *files = NULL;
	int f_flags = 0, ret = -ENOENT;
	struct file *file = NULL;
	struct task_struct *task;

	task = get_proc_task(m->private);
	if (!task)
		return -ENOENT;

	files = get_files_struct(task);
	put_task_struct(task);

	if (files) {
		int fd = proc_fd(m->private);

		spin_lock(&files->file_lock);
		file = fcheck_files(files, fd);
		if (file) {
			struct fdtable *fdt = files_fdtable(files);

			f_flags = file->f_flags & ~O_CLOEXEC;
			if (close_on_exec(fd, fdt))
				f_flags |= O_CLOEXEC;

			get_file(file);
			ret = 0;
		}
		spin_unlock(&files->file_lock);
		put_files_struct(files);
	}

	if (!ret) {
                seq_printf(m, "pos:\t%lli\nflags:\t0%o\n",
			   (long long)file->f_pos, f_flags);
		fput(file);
	}

	return ret;
}

static int seq_fdinfo_open(struct inode *inode, struct file *file)
{
	return single_open(file, seq_show, inode);
}

static const struct file_operations proc_fdinfo_file_operations = {
	.open		= seq_fdinfo_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
{
	struct files_struct *files;
	struct task_struct *task;
	const struct cred *cred;
	struct inode *inode;
	int fd;

	if (flags & LOOKUP_RCU)
		return -ECHILD;

	inode = dentry->d_inode;
	task = get_proc_task(inode);
	fd = proc_fd(inode);

	if (task) {
		files = get_files_struct(task);
		if (files) {
			struct file *file;

			rcu_read_lock();
			file = fcheck_files(files, fd);
			if (file) {
				unsigned f_mode = file->f_mode;

				rcu_read_unlock();
				put_files_struct(files);

				if (task_dumpable(task)) {
					rcu_read_lock();
					cred = __task_cred(task);
					inode->i_uid = cred->euid;
					inode->i_gid = cred->egid;
					rcu_read_unlock();
				} else {
					inode->i_uid = GLOBAL_ROOT_UID;
					inode->i_gid = GLOBAL_ROOT_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);
				put_task_struct(task);
				return 1;
			}
			rcu_read_unlock();
			put_files_struct(files);
		}
		put_task_struct(task);
	}

	d_drop(dentry);
	return 0;
}

static const struct dentry_operations tid_fd_dentry_operations = {
	.d_revalidate	= tid_fd_revalidate,
	.d_delete	= pid_delete_dentry,
};

static int proc_fd_link(struct dentry *dentry, struct path *path)
{
	struct files_struct *files = NULL;
	struct task_struct *task;
	int ret = -ENOENT;

	task = get_proc_task(dentry->d_inode);
	if (task) {
		files = get_files_struct(task);
		put_task_struct(task);
	}

	if (files) {
		int fd = proc_fd(dentry->d_inode);
		struct file *fd_file;

		spin_lock(&files->file_lock);
		fd_file = fcheck_files(files, fd);
		if (fd_file) {
			*path = fd_file->f_path;
			path_get(&fd_file->f_path);
			ret = 0;
		}
		spin_unlock(&files->file_lock);
		put_files_struct(files);
	}

	return ret;
}

static struct dentry *
proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
		    struct task_struct *task, const void *ptr)
{
	struct dentry *error = ERR_PTR(-ENOENT);
	unsigned fd = (unsigned long)ptr;
	struct proc_inode *ei;
	struct inode *inode;

	inode = proc_pid_make_inode(dir->i_sb, task);
	if (!inode)
		goto out;

	ei = PROC_I(inode);
	ei->fd = fd;

	inode->i_mode = S_IFLNK;
	inode->i_op = &proc_pid_link_inode_operations;
	inode->i_size = 64;

	ei->op.proc_get_link = proc_fd_link;

	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))
		error = NULL;
 out:
	return error;
}

static struct dentry *proc_lookupfd_common(struct inode *dir,
					   struct dentry *dentry,
					   instantiate_t instantiate)
{
	struct task_struct *task = get_proc_task(dir);
	struct dentry *result = ERR_PTR(-ENOENT);
	unsigned fd = name_to_int(dentry);

	if (!task)
		goto out_no_task;
	if (fd == ~0U)
		goto out;

	result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
out:
	put_task_struct(task);
out_no_task:
	return result;
}

static int proc_readfd_common(struct file * filp, void * dirent,
			      filldir_t filldir, instantiate_t instantiate)
{
	struct dentry *dentry = filp->f_path.dentry;
	struct inode *inode = dentry->d_inode;
	struct task_struct *p = get_proc_task(inode);
	struct files_struct *files;
	unsigned int fd, ino;
	int retval;

	retval = -ENOENT;
	if (!p)
		goto out_no_task;
	retval = 0;

	fd = filp->f_pos;
	switch (fd) {
		case 0:
			if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
				goto out;
			filp->f_pos++;
		case 1:
			ino = parent_ino(dentry);
			if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
				goto out;
			filp->f_pos++;
		default:
			files = get_files_struct(p);
			if (!files)
				goto out;
			rcu_read_lock();
			for (fd = filp->f_pos - 2;
			     fd < files_fdtable(files)->max_fds;
			     fd++, filp->f_pos++) {
				char name[PROC_NUMBUF];
				int len;
				int rv;

				if (!fcheck_files(files, fd))
					continue;
				rcu_read_unlock();

				len = snprintf(name, sizeof(name), "%d", fd);
				rv = proc_fill_cache(filp, dirent, filldir,
						     name, len, instantiate, p,
						     (void *)(unsigned long)fd);
				if (rv < 0)
					goto out_fd_loop;
				rcu_read_lock();
			}
			rcu_read_unlock();
out_fd_loop:
			put_files_struct(files);
	}
out:
	put_task_struct(p);
out_no_task:
	return retval;
}

static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
{
	return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
}

const struct file_operations proc_fd_operations = {
	.read		= generic_read_dir,
	.readdir	= proc_readfd,
	.llseek		= default_llseek,
};

static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
				    unsigned int flags)
{
	return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
}

/*
 * /proc/pid/fd needs a special permission handler so that a process can still
 * access /proc/self/fd after it has executed a setuid().
 */
int proc_fd_permission(struct inode *inode, int mask)
{
	int rv = generic_permission(inode, mask);
	if (rv == 0)
		return 0;
	if (task_pid(current) == proc_pid(inode))
		rv = 0;
	return rv;
}

const struct inode_operations proc_fd_inode_operations = {
	.lookup		= proc_lookupfd,
	.permission	= proc_fd_permission,
	.setattr	= proc_setattr,
};

static struct dentry *
proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
			struct task_struct *task, const void *ptr)
{
	struct dentry *error = ERR_PTR(-ENOENT);
	unsigned fd = (unsigned long)ptr;
	struct proc_inode *ei;
	struct inode *inode;

	inode = proc_pid_make_inode(dir->i_sb, task);
	if (!inode)
		goto out;

	ei = PROC_I(inode);
	ei->fd = fd;

	inode->i_mode = S_IFREG | S_IRUSR;
	inode->i_fop = &proc_fdinfo_file_operations;

	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))
		error = NULL;
 out:
	return error;
}

static struct dentry *
proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
	return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
}

static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
{
	return proc_readfd_common(filp, dirent, filldir,
				  proc_fdinfo_instantiate);
}

const struct inode_operations proc_fdinfo_inode_operations = {
	.lookup		= proc_lookupfdinfo,
	.setattr	= proc_setattr,
};

const struct file_operations proc_fdinfo_operations = {
	.read		= generic_read_dir,
	.readdir	= proc_readfdinfo,
	.llseek		= default_llseek,
};
Commit	Line	Data
faf60af1 CG	1	#include <linux/sched.h>
	2	#include <linux/errno.h>
	3	#include <linux/dcache.h>
	4	#include <linux/path.h>
	5	#include <linux/fdtable.h>
	6	#include <linux/namei.h>
	7	#include <linux/pid.h>
	8	#include <linux/security.h>
ddd3e077 CG	9	#include <linux/file.h>
ddd3e077 CG	10	#include <linux/seq_file.h>
faf60af1 CG	11
	12	#include <linux/proc_fs.h>
	13
	14	#include "internal.h"
	15	#include "fd.h"
	16
ddd3e077	17	static int seq_show(struct seq_file m, void v)
faf60af1	18	{
faf60af1	19	struct files_struct *files = NULL;
ddd3e077 CG	20	int f_flags = 0, ret = -ENOENT;
	21	struct file *file = NULL;
	22	struct task_struct *task;
	23
	24	task = get_proc_task(m->private);
	25	if (!task)
	26	return -ENOENT;
	27
	28	files = get_files_struct(task);
	29	put_task_struct(task);
faf60af1	30
faf60af1	31	if (files) {
ddd3e077 CG	32	int fd = proc_fd(m->private);
ddd3e077 CG	33
faf60af1 CG	34	spin_lock(&files->file_lock);
	35	file = fcheck_files(files, fd);
	36	if (file) {
ddd3e077	37	struct fdtable *fdt = files_fdtable(files);
faf60af1	38
faf60af1 CG	39	f_flags = file->f_flags & ~O_CLOEXEC;
	40	if (close_on_exec(fd, fdt))
	41	f_flags \|= O_CLOEXEC;
	42
ddd3e077 CG	43	get_file(file);
ddd3e077 CG	44	ret = 0;
faf60af1 CG	45	}
	46	spin_unlock(&files->file_lock);
	47	put_files_struct(files);
	48	}
ddd3e077 CG	49
	50	if (!ret) {
	51	seq_printf(m, "pos:\t%lli\nflags:\t0%o\n",
	52	(long long)file->f_pos, f_flags);
	53	fput(file);
	54	}
	55
	56	return ret;
faf60af1 CG	57	}
faf60af1 CG	58
ddd3e077 CG	59	static int seq_fdinfo_open(struct inode inode, struct file file)
	60	{
	61	return single_open(file, seq_show, inode);
	62	}
	63
	64	static const struct file_operations proc_fdinfo_file_operations = {
	65	.open = seq_fdinfo_open,
	66	.read = seq_read,
	67	.llseek = seq_lseek,
	68	.release = single_release,
	69	};
	70
faf60af1 CG	71	static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
	72	{
	73	struct files_struct *files;
	74	struct task_struct *task;
	75	const struct cred *cred;
	76	struct inode *inode;
	77	int fd;
	78
	79	if (flags & LOOKUP_RCU)
	80	return -ECHILD;
	81
	82	inode = dentry->d_inode;
	83	task = get_proc_task(inode);
	84	fd = proc_fd(inode);
	85
	86	if (task) {
	87	files = get_files_struct(task);
	88	if (files) {
	89	struct file *file;
	90
	91	rcu_read_lock();
	92	file = fcheck_files(files, fd);
	93	if (file) {
	94	unsigned f_mode = file->f_mode;
	95
	96	rcu_read_unlock();
	97	put_files_struct(files);
	98
	99	if (task_dumpable(task)) {
	100	rcu_read_lock();
	101	cred = __task_cred(task);
	102	inode->i_uid = cred->euid;
	103	inode->i_gid = cred->egid;
	104	rcu_read_unlock();
	105	} else {
	106	inode->i_uid = GLOBAL_ROOT_UID;
	107	inode->i_gid = GLOBAL_ROOT_GID;
	108	}
	109
	110	if (S_ISLNK(inode->i_mode)) {
	111	unsigned i_mode = S_IFLNK;
	112	if (f_mode & FMODE_READ)
	113	i_mode \|= S_IRUSR \| S_IXUSR;
	114	if (f_mode & FMODE_WRITE)
	115	i_mode \|= S_IWUSR \| S_IXUSR;
	116	inode->i_mode = i_mode;
	117	}
	118
	119	security_task_to_inode(task, inode);
	120	put_task_struct(task);
	121	return 1;
	122	}
	123	rcu_read_unlock();
	124	put_files_struct(files);
	125	}
	126	put_task_struct(task);
	127	}
	128
	129	d_drop(dentry);
	130	return 0;
	131	}
	132
	133	static const struct dentry_operations tid_fd_dentry_operations = {
	134	.d_revalidate = tid_fd_revalidate,
135	.d_delete = pid_delete_dentry,
136	};
137
138	static int proc_fd_link(struct dentry dentry, struct path path)
139	{
ddd3e077 CG	140	struct files_struct *files = NULL;
	141	struct task_struct *task;
	142	int ret = -ENOENT;
	143
	144	task = get_proc_task(dentry->d_inode);
	145	if (task) {
	146	files = get_files_struct(task);
	147	put_task_struct(task);
	148	}
	149
	150	if (files) {
	151	int fd = proc_fd(dentry->d_inode);
	152	struct file *fd_file;
	153
	154	spin_lock(&files->file_lock);
	155	fd_file = fcheck_files(files, fd);
	156	if (fd_file) {
	157	*path = fd_file->f_path;
	158	path_get(&fd_file->f_path);
	159	ret = 0;
	160	}
	161	spin_unlock(&files->file_lock);
	162	put_files_struct(files);
	163	}
	164
	165	return ret;
faf60af1 CG	166	}
	167
	168	static struct dentry *
	169	proc_fd_instantiate(struct inode dir, struct dentry dentry,
	170	struct task_struct task, const void ptr)
	171	{
	172	struct dentry *error = ERR_PTR(-ENOENT);
	173	unsigned fd = (unsigned long)ptr;
	174	struct proc_inode *ei;
	175	struct inode *inode;
	176
	177	inode = proc_pid_make_inode(dir->i_sb, task);
	178	if (!inode)
	179	goto out;
	180
	181	ei = PROC_I(inode);
	182	ei->fd = fd;
	183
	184	inode->i_mode = S_IFLNK;
	185	inode->i_op = &proc_pid_link_inode_operations;
	186	inode->i_size = 64;
	187
	188	ei->op.proc_get_link = proc_fd_link;
	189
	190	d_set_d_op(dentry, &tid_fd_dentry_operations);
	191	d_add(dentry, inode);
	192
	193	/* Close the race of the process dying before we return the dentry */
	194	if (tid_fd_revalidate(dentry, 0))
	195	error = NULL;
	196	out:
	197	return error;
	198	}
	199
	200	static struct dentry proc_lookupfd_common(struct inode dir,
	201	struct dentry *dentry,
	202	instantiate_t instantiate)
	203	{
	204	struct task_struct *task = get_proc_task(dir);
	205	struct dentry *result = ERR_PTR(-ENOENT);
	206	unsigned fd = name_to_int(dentry);
	207
	208	if (!task)
	209	goto out_no_task;
	210	if (fd == ~0U)
	211	goto out;
	212
	213	result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
	214	out:
	215	put_task_struct(task);
	216	out_no_task:
	217	return result;
	218	}
	219
	220	static int proc_readfd_common(struct file * filp, void * dirent,
	221	filldir_t filldir, instantiate_t instantiate)
	222	{
	223	struct dentry *dentry = filp->f_path.dentry;
	224	struct inode *inode = dentry->d_inode;
	225	struct task_struct *p = get_proc_task(inode);
	226	struct files_struct *files;
	227	unsigned int fd, ino;
	228	int retval;
	229
230	retval = -ENOENT;
231	if (!p)
232	goto out_no_task;
233	retval = 0;
234
235	fd = filp->f_pos;
236	switch (fd) {
237	case 0:
238	if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
239	goto out;
240	filp->f_pos++;
241	case 1:
242	ino = parent_ino(dentry);
243	if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
244	goto out;
245	filp->f_pos++;
246	default:
247	files = get_files_struct(p);
248	if (!files)
249	goto out;
250	rcu_read_lock();
251	for (fd = filp->f_pos - 2;
252	fd < files_fdtable(files)->max_fds;
253	fd++, filp->f_pos++) {
254	char name[PROC_NUMBUF];
255	int len;
256	int rv;
257
258	if (!fcheck_files(files, fd))
259	continue;
260	rcu_read_unlock();
261
262	len = snprintf(name, sizeof(name), "%d", fd);
263	rv = proc_fill_cache(filp, dirent, filldir,
264	name, len, instantiate, p,
265	(void *)(unsigned long)fd);
266	if (rv < 0)
267	goto out_fd_loop;
268	rcu_read_lock();
269	}
270	rcu_read_unlock();
271	out_fd_loop:
272	put_files_struct(files);
273	}
274	out:
275	put_task_struct(p);
276	out_no_task:
277	return retval;
278	}
279
faf60af1 CG	280	static int proc_readfd(struct file filp, void dirent, filldir_t filldir)
	281	{
	282	return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
	283	}
	284
	285	const struct file_operations proc_fd_operations = {
	286	.read = generic_read_dir,
	287	.readdir = proc_readfd,
	288	.llseek = default_llseek,
	289	};
	290
	291	static struct dentry proc_lookupfd(struct inode dir, struct dentry *dentry,
	292	unsigned int flags)
	293	{
	294	return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
	295	}
	296
	297	/*
	298	* /proc/pid/fd needs a special permission handler so that a process can still
	299	* access /proc/self/fd after it has executed a setuid().
	300	*/
	301	int proc_fd_permission(struct inode *inode, int mask)
	302	{
	303	int rv = generic_permission(inode, mask);
	304	if (rv == 0)
	305	return 0;
	306	if (task_pid(current) == proc_pid(inode))
	307	rv = 0;
	308	return rv;
	309	}
	310
	311	const struct inode_operations proc_fd_inode_operations = {
	312	.lookup = proc_lookupfd,
	313	.permission = proc_fd_permission,
	314	.setattr = proc_setattr,
	315	};
	316
	317	static struct dentry *
	318	proc_fdinfo_instantiate(struct inode dir, struct dentry dentry,
	319	struct task_struct task, const void ptr)
	320	{
	321	struct dentry *error = ERR_PTR(-ENOENT);
	322	unsigned fd = (unsigned long)ptr;
	323	struct proc_inode *ei;
	324	struct inode *inode;
	325
	326	inode = proc_pid_make_inode(dir->i_sb, task);
	327	if (!inode)
	328	goto out;
	329
	330	ei = PROC_I(inode);
	331	ei->fd = fd;
	332
	333	inode->i_mode = S_IFREG \| S_IRUSR;
	334	inode->i_fop = &proc_fdinfo_file_operations;
	335
	336	d_set_d_op(dentry, &tid_fd_dentry_operations);
	337	d_add(dentry, inode);
	338
	339	/* Close the race of the process dying before we return the dentry */
	340	if (tid_fd_revalidate(dentry, 0))
	341	error = NULL;
	342	out:
	343	return error;
344	}
345
346	static struct dentry *
347	proc_lookupfdinfo(struct inode dir, struct dentry dentry, unsigned int flags)
348	{
349	return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
350	}
351
352	static int proc_readfdinfo(struct file filp, void dirent, filldir_t filldir)
353	{
354	return proc_readfd_common(filp, dirent, filldir,
355	proc_fdinfo_instantiate);
356	}
357
358	const struct inode_operations proc_fdinfo_inode_operations = {
359	.lookup = proc_lookupfdinfo,
360	.setattr = proc_setattr,
361	};
362
363	const struct file_operations proc_fdinfo_operations = {
364	.read = generic_read_dir,
365	.readdir = proc_readfdinfo,
366	.llseek = default_llseek,
367	};