Commit e656d8a6 authored by Eric W. Biederman's avatar Eric W. Biederman

procfs: Use the proc generic infrastructure for proc/self.

I had visions at one point of splitting proc into two filesystems.  If
that had happened proc/self being the the part of proc that actually deals
with pids would have been a nice cleanup.  As it is proc/self requires
a lot of unnecessary infrastructure for a single file.

The only user visible change is that a mounted /proc for a pid namespace
that is dead now shows a broken proc symlink, instead of being completely
invisible.  I don't think anyone will notice or care.
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent dd34ad35
......@@ -21,6 +21,7 @@ proc-y += uptime.o
proc-y += version.o
proc-y += softirqs.o
proc-y += namespaces.o
proc-y += self.o
proc-$(CONFIG_PROC_SYSCTL) += proc_sysctl.o
proc-$(CONFIG_NET) += proc_net.o
proc-$(CONFIG_PROC_KCORE) += kcore.o
......
......@@ -2237,146 +2237,6 @@ static const struct file_operations proc_coredump_filter_operations = {
};
#endif
/*
* /proc/self:
*/
static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
int buflen)
{
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char tmp[PROC_NUMBUF];
if (!tgid)
return -ENOENT;
sprintf(tmp, "%d", tgid);
return vfs_readlink(dentry,buffer,buflen,tmp);
}
static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name = ERR_PTR(-ENOENT);
if (tgid) {
/* 11 for max length of signed int in decimal + NULL term */
name = kmalloc(12, GFP_KERNEL);
if (!name)
name = ERR_PTR(-ENOMEM);
else
sprintf(name, "%d", tgid);
}
nd_set_link(nd, name);
return NULL;
}
static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
void *cookie)
{
char *s = nd_get_link(nd);
if (!IS_ERR(s))
kfree(s);
}
static const struct inode_operations proc_self_inode_operations = {
.readlink = proc_self_readlink,
.follow_link = proc_self_follow_link,
.put_link = proc_self_put_link,
};
/*
* proc base
*
* These are the directory entries in the root directory of /proc
* that properly belong to the /proc filesystem, as they describe
* describe something that is process related.
*/
static const struct pid_entry proc_base_stuff[] = {
NOD("self", S_IFLNK|S_IRWXUGO,
&proc_self_inode_operations, NULL, {}),
};
static struct dentry *proc_base_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
const struct pid_entry *p = ptr;
struct inode *inode;
struct proc_inode *ei;
struct dentry *error;
/* Allocate the inode */
error = ERR_PTR(-ENOMEM);
inode = new_inode(dir->i_sb);
if (!inode)
goto out;
/* Initialize the inode */
ei = PROC_I(inode);
inode->i_ino = get_next_ino();
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
/*
* grab the reference to the task.
*/
ei->pid = get_task_pid(task, PIDTYPE_PID);
if (!ei->pid)
goto out_iput;
inode->i_mode = p->mode;
if (S_ISDIR(inode->i_mode))
set_nlink(inode, 2);
if (S_ISLNK(inode->i_mode))
inode->i_size = 64;
if (p->iop)
inode->i_op = p->iop;
if (p->fop)
inode->i_fop = p->fop;
ei->op = p->op;
d_add(dentry, inode);
error = NULL;
out:
return error;
out_iput:
iput(inode);
goto out;
}
static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
{
struct dentry *error;
struct task_struct *task = get_proc_task(dir);
const struct pid_entry *p, *last;
error = ERR_PTR(-ENOENT);
if (!task)
goto out_no_task;
/* Lookup the directory entry */
last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
for (p = proc_base_stuff; p <= last; p++) {
if (p->len != dentry->d_name.len)
continue;
if (!memcmp(dentry->d_name.name, p->name, p->len))
break;
}
if (p > last)
goto out;
error = proc_base_instantiate(dir, dentry, task, p);
out:
put_task_struct(task);
out_no_task:
return error;
}
static int proc_base_fill_cache(struct file *filp, void *dirent,
filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
{
return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
proc_base_instantiate, task, p);
}
#ifdef CONFIG_TASK_IO_ACCOUNTING
static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
{
......@@ -2767,15 +2627,11 @@ static struct dentry *proc_pid_instantiate(struct inode *dir,
struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
{
struct dentry *result;
struct dentry *result = NULL;
struct task_struct *task;
unsigned tgid;
struct pid_namespace *ns;
result = proc_base_lookup(dir, dentry);
if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
goto out;
tgid = name_to_int(dentry);
if (tgid == ~0U)
goto out;
......@@ -2838,7 +2694,7 @@ static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter ite
return iter;
}
#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
#define TGID_OFFSET (FIRST_PROCESS_ENTRY)
static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct tgid_iter iter)
......@@ -2872,12 +2728,6 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
if (!reaper)
goto out_no_task;
for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
const struct pid_entry *p = &proc_base_stuff[nr];
if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
goto out;
}
ns = filp->f_dentry->d_sb->s_fs_info;
iter.task = NULL;
iter.tgid = filp->f_pos - TGID_OFFSET;
......
......@@ -15,6 +15,7 @@ struct ctl_table_header;
struct mempolicy;
extern struct proc_dir_entry proc_root;
extern void proc_self_init(void);
#ifdef CONFIG_PROC_SYSCTL
extern int proc_sys_init(void);
extern void sysctl_head_put(struct ctl_table_header *head);
......
......@@ -169,6 +169,7 @@ void __init proc_root_init(void)
return;
}
proc_self_init();
proc_symlink("mounts", NULL, "self/mounts");
proc_net_init();
......
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/namei.h>
/*
* /proc/self:
*/
static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
int buflen)
{
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char tmp[PROC_NUMBUF];
if (!tgid)
return -ENOENT;
sprintf(tmp, "%d", tgid);
return vfs_readlink(dentry,buffer,buflen,tmp);
}
static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name = ERR_PTR(-ENOENT);
if (tgid) {
/* 11 for max length of signed int in decimal + NULL term */
name = kmalloc(12, GFP_KERNEL);
if (!name)
name = ERR_PTR(-ENOMEM);
else
sprintf(name, "%d", tgid);
}
nd_set_link(nd, name);
return NULL;
}
static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
void *cookie)
{
char *s = nd_get_link(nd);
if (!IS_ERR(s))
kfree(s);
}
static const struct inode_operations proc_self_inode_operations = {
.readlink = proc_self_readlink,
.follow_link = proc_self_follow_link,
.put_link = proc_self_put_link,
};
void __init proc_self_init(void)
{
struct proc_dir_entry *proc_self_symlink;
mode_t mode;
mode = S_IFLNK | S_IRWXUGO;
proc_self_symlink = proc_create("self", mode, NULL, NULL );
proc_self_symlink->proc_iops = &proc_self_inode_operations;
}
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