blob: 02a63ac04178e64c8f7e2a3bddee2fcadeaf8254 [file] [log] [blame]
/*
* linux/fs/proc/base.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* proc base directory handling functions
*
* 1999, Al Viro. Rewritten. Now it covers the whole per-process part.
* Instead of using magical inumbers to determine the kind of object
* we allocate and fill in-core inodes upon lookup. They don't even
* go into icache. We cache the reference to task_struct upon lookup too.
* Eventually it should become a filesystem in its own. We don't use the
* rest of procfs anymore.
*
*
* Changelog:
* 17-Jan-2005
* Allan Bezerra
* Bruna Moreira <bruna.moreira@indt.org.br>
* Edjard Mota <edjard.mota@indt.org.br>
* Ilias Biris <ilias.biris@indt.org.br>
* Mauricio Lin <mauricio.lin@indt.org.br>
*
* Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
*
* A new process specific entry (smaps) included in /proc. It shows the
* size of rss for each memory area. The maps entry lacks information
* about physical memory size (rss) for each mapped file, i.e.,
* rss information for executables and library files.
* This additional information is useful for any tools that need to know
* about physical memory consumption for a process specific library.
*
* Changelog:
* 21-Feb-2005
* Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
* Pud inclusion in the page table walking.
*
* ChangeLog:
* 10-Mar-2005
* 10LE Instituto Nokia de Tecnologia - INdT:
* A better way to walks through the page table as suggested by Hugh Dickins.
*
* Simo Piiroinen <simo.piiroinen@nokia.com>:
* Smaps information related to shared, private, clean and dirty pages.
*
* Paul Mundt <paul.mundt@nokia.com>:
* Overall revision about smaps.
*/
#include <asm/uaccess.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/namei.h>
#include <linux/mnt_namespace.h>
#include <linux/mm.h>
#include <linux/rcupdate.h>
#include <linux/kallsyms.h>
#include <linux/resource.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/cgroup.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
#include <linux/poll.h>
#include <linux/nsproxy.h>
#include <linux/oom.h>
#include <linux/elf.h>
#include <linux/pid_namespace.h>
#include "internal.h"
/* NOTE:
* Implementing inode permission operations in /proc is almost
* certainly an error. Permission checks need to happen during
* each system call not at open time. The reason is that most of
* what we wish to check for permissions in /proc varies at runtime.
*
* The classic example of a problem is opening file descriptors
* in /proc for a task before it execs a suid executable.
*/
/* Worst case buffer size needed for holding an integer. */
#define PROC_NUMBUF 13
struct pid_entry {
char *name;
int len;
mode_t mode;
const struct inode_operations *iop;
const struct file_operations *fop;
union proc_op op;
};
#define NOD(NAME, MODE, IOP, FOP, OP) { \
.name = (NAME), \
.len = sizeof(NAME) - 1, \
.mode = MODE, \
.iop = IOP, \
.fop = FOP, \
.op = OP, \
}
#define DIR(NAME, MODE, OTYPE) \
NOD(NAME, (S_IFDIR|(MODE)), \
&proc_##OTYPE##_inode_operations, &proc_##OTYPE##_operations, \
{} )
#define LNK(NAME, OTYPE) \
NOD(NAME, (S_IFLNK|S_IRWXUGO), \
&proc_pid_link_inode_operations, NULL, \
{ .proc_get_link = &proc_##OTYPE##_link } )
#define REG(NAME, MODE, OTYPE) \
NOD(NAME, (S_IFREG|(MODE)), NULL, \
&proc_##OTYPE##_operations, {})
#define INF(NAME, MODE, OTYPE) \
NOD(NAME, (S_IFREG|(MODE)), \
NULL, &proc_info_file_operations, \
{ .proc_read = &proc_##OTYPE } )
int maps_protect;
EXPORT_SYMBOL(maps_protect);
static struct fs_struct *get_fs_struct(struct task_struct *task)
{
struct fs_struct *fs;
task_lock(task);
fs = task->fs;
if(fs)
atomic_inc(&fs->count);
task_unlock(task);
return fs;
}
static int get_nr_threads(struct task_struct *tsk)
{
/* Must be called with the rcu_read_lock held */
unsigned long flags;
int count = 0;
if (lock_task_sighand(tsk, &flags)) {
count = atomic_read(&tsk->signal->count);
unlock_task_sighand(tsk, &flags);
}
return count;
}
static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
struct task_struct *task = get_proc_task(inode);
struct fs_struct *fs = NULL;
int result = -ENOENT;
if (task) {
fs = get_fs_struct(task);
put_task_struct(task);
}
if (fs) {
read_lock(&fs->lock);
*mnt = mntget(fs->pwdmnt);
*dentry = dget(fs->pwd);
read_unlock(&fs->lock);
result = 0;
put_fs_struct(fs);
}
return result;
}
static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
struct task_struct *task = get_proc_task(inode);
struct fs_struct *fs = NULL;
int result = -ENOENT;
if (task) {
fs = get_fs_struct(task);
put_task_struct(task);
}
if (fs) {
read_lock(&fs->lock);
*mnt = mntget(fs->rootmnt);
*dentry = dget(fs->root);
read_unlock(&fs->lock);
result = 0;
put_fs_struct(fs);
}
return result;
}
#define MAY_PTRACE(task) \
(task == current || \
(task->parent == current && \
(task->ptrace & PT_PTRACED) && \
(task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
security_ptrace(current,task) == 0))
static int proc_pid_cmdline(struct task_struct *task, char * buffer)
{
int res = 0;
unsigned int len;
struct mm_struct *mm = get_task_mm(task);
if (!mm)
goto out;
if (!mm->arg_end)
goto out_mm; /* Shh! No looking before we're done */
len = mm->arg_end - mm->arg_start;
if (len > PAGE_SIZE)
len = PAGE_SIZE;
res = access_process_vm(task, mm->arg_start, buffer, len, 0);
// If the nul at the end of args has been overwritten, then
// assume application is using setproctitle(3).
if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
len = strnlen(buffer, res);
if (len < res) {
res = len;
} else {
len = mm->env_end - mm->env_start;
if (len > PAGE_SIZE - res)
len = PAGE_SIZE - res;
res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
res = strnlen(buffer, res);
}
}
out_mm:
mmput(mm);
out:
return res;
}
static int proc_pid_auxv(struct task_struct *task, char *buffer)
{
int res = 0;
struct mm_struct *mm = get_task_mm(task);
if (mm) {
unsigned int nwords = 0;
do
nwords += 2;
while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
res = nwords * sizeof(mm->saved_auxv[0]);
if (res > PAGE_SIZE)
res = PAGE_SIZE;
memcpy(buffer, mm->saved_auxv, res);
mmput(mm);
}
return res;
}
#ifdef CONFIG_KALLSYMS
/*
* Provides a wchan file via kallsyms in a proper one-value-per-file format.
* Returns the resolved symbol. If that fails, simply return the address.
*/
static int proc_pid_wchan(struct task_struct *task, char *buffer)
{
unsigned long wchan;
char symname[KSYM_NAME_LEN];
wchan = get_wchan(task);
if (lookup_symbol_name(wchan, symname) < 0)
return sprintf(buffer, "%lu", wchan);
else
return sprintf(buffer, "%s", symname);
}
#endif /* CONFIG_KALLSYMS */
#ifdef CONFIG_SCHEDSTATS
/*
* Provides /proc/PID/schedstat
*/
static int proc_pid_schedstat(struct task_struct *task, char *buffer)
{
return sprintf(buffer, "%llu %llu %lu\n",
task->sched_info.cpu_time,
task->sched_info.run_delay,
task->sched_info.pcount);
}
#endif
/* The badness from the OOM killer */
unsigned long badness(struct task_struct *p, unsigned long uptime);
static int proc_oom_score(struct task_struct *task, char *buffer)
{
unsigned long points;
struct timespec uptime;
do_posix_clock_monotonic_gettime(&uptime);
read_lock(&tasklist_lock);
points = badness(task, uptime.tv_sec);
read_unlock(&tasklist_lock);
return sprintf(buffer, "%lu\n", points);
}
struct limit_names {
char *name;
char *unit;
};
static const struct limit_names lnames[RLIM_NLIMITS] = {
[RLIMIT_CPU] = {"Max cpu time", "ms"},
[RLIMIT_FSIZE] = {"Max file size", "bytes"},
[RLIMIT_DATA] = {"Max data size", "bytes"},
[RLIMIT_STACK] = {"Max stack size", "bytes"},
[RLIMIT_CORE] = {"Max core file size", "bytes"},
[RLIMIT_RSS] = {"Max resident set", "bytes"},
[RLIMIT_NPROC] = {"Max processes", "processes"},
[RLIMIT_NOFILE] = {"Max open files", "files"},
[RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
[RLIMIT_AS] = {"Max address space", "bytes"},
[RLIMIT_LOCKS] = {"Max file locks", "locks"},
[RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
[RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
[RLIMIT_NICE] = {"Max nice priority", NULL},
[RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
};
/* Display limits for a process */
static int proc_pid_limits(struct task_struct *task, char *buffer)
{
unsigned int i;
int count = 0;
unsigned long flags;
char *bufptr = buffer;
struct rlimit rlim[RLIM_NLIMITS];
rcu_read_lock();
if (!lock_task_sighand(task,&flags)) {
rcu_read_unlock();
return 0;
}
memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
unlock_task_sighand(task, &flags);
rcu_read_unlock();
/*
* print the file header
*/
count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
"Limit", "Soft Limit", "Hard Limit", "Units");
for (i = 0; i < RLIM_NLIMITS; i++) {
if (rlim[i].rlim_cur == RLIM_INFINITY)
count += sprintf(&bufptr[count], "%-25s %-20s ",
lnames[i].name, "unlimited");
else
count += sprintf(&bufptr[count], "%-25s %-20lu ",
lnames[i].name, rlim[i].rlim_cur);
if (rlim[i].rlim_max == RLIM_INFINITY)
count += sprintf(&bufptr[count], "%-20s ", "unlimited");
else
count += sprintf(&bufptr[count], "%-20lu ",
rlim[i].rlim_max);
if (lnames[i].unit)
count += sprintf(&bufptr[count], "%-10s\n",
lnames[i].unit);
else
count += sprintf(&bufptr[count], "\n");
}
return count;
}
/************************************************************************/
/* Here the fs part begins */
/************************************************************************/
/* permission checks */
static int proc_fd_access_allowed(struct inode *inode)
{
struct task_struct *task;
int allowed = 0;
/* Allow access to a task's file descriptors if it is us or we
* may use ptrace attach to the process and find out that
* information.
*/
task = get_proc_task(inode);
if (task) {
allowed = ptrace_may_attach(task);
put_task_struct(task);
}
return allowed;
}
static int proc_setattr(struct dentry *dentry, struct iattr *attr)
{
int error;
struct inode *inode = dentry->d_inode;
if (attr->ia_valid & ATTR_MODE)
return -EPERM;
error = inode_change_ok(inode, attr);
if (!error)
error = inode_setattr(inode, attr);
return error;
}
static const struct inode_operations proc_def_inode_operations = {
.setattr = proc_setattr,
};
extern struct seq_operations mounts_op;
struct proc_mounts {
struct seq_file m;
int event;
};
static int mounts_open(struct inode *inode, struct file *file)
{
struct task_struct *task = get_proc_task(inode);
struct nsproxy *nsp;
struct mnt_namespace *ns = NULL;
struct proc_mounts *p;
int ret = -EINVAL;
if (task) {
rcu_read_lock();
nsp = task_nsproxy(task);
if (nsp) {
ns = nsp->mnt_ns;
if (ns)
get_mnt_ns(ns);
}
rcu_read_unlock();
put_task_struct(task);
}
if (ns) {
ret = -ENOMEM;
p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
if (p) {
file->private_data = &p->m;
ret = seq_open(file, &mounts_op);
if (!ret) {
p->m.private = ns;
p->event = ns->event;
return 0;
}
kfree(p);
}
put_mnt_ns(ns);
}
return ret;
}
static int mounts_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
struct mnt_namespace *ns = m->private;
put_mnt_ns(ns);
return seq_release(inode, file);
}
static unsigned mounts_poll(struct file *file, poll_table *wait)
{
struct proc_mounts *p = file->private_data;
struct mnt_namespace *ns = p->m.private;
unsigned res = 0;
poll_wait(file, &ns->poll, wait);
spin_lock(&vfsmount_lock);
if (p->event != ns->event) {
p->event = ns->event;
res = POLLERR;
}
spin_unlock(&vfsmount_lock);
return res;
}
static const struct file_operations proc_mounts_operations = {
.open = mounts_open,
.read = seq_read,
.llseek = seq_lseek,
.release = mounts_release,
.poll = mounts_poll,
};
extern struct seq_operations mountstats_op;
static int mountstats_open(struct inode *inode, struct file *file)
{
int ret = seq_open(file, &mountstats_op);
if (!ret) {
struct seq_file *m = file->private_data;
struct nsproxy *nsp;
struct mnt_namespace *mnt_ns = NULL;
struct task_struct *task = get_proc_task(inode);
if (task) {
rcu_read_lock();
nsp = task_nsproxy(task);
if (nsp) {
mnt_ns = nsp->mnt_ns;
if (mnt_ns)
get_mnt_ns(mnt_ns);
}
rcu_read_unlock();
put_task_struct(task);
}
if (mnt_ns)
m->private = mnt_ns;
else {
seq_release(inode, file);
ret = -EINVAL;
}
}
return ret;
}
static const struct file_operations proc_mountstats_operations = {
.open = mountstats_open,
.read = seq_read,
.llseek = seq_lseek,
.release = mounts_release,
};
#define PROC_BLOCK_SIZE (3*1024) /* 4K page size but our output routines use some slack for overruns */
static ssize_t proc_info_read(struct file * file, char __user * buf,
size_t count, loff_t *ppos)
{
struct inode * inode = file->f_path.dentry->d_inode;
unsigned long page;
ssize_t length;
struct task_struct *task = get_proc_task(inode);
length = -ESRCH;
if (!task)
goto out_no_task;
if (count > PROC_BLOCK_SIZE)
count = PROC_BLOCK_SIZE;
length = -ENOMEM;
if (!(page = __get_free_page(GFP_TEMPORARY)))
goto out;
length = PROC_I(inode)->op.proc_read(task, (char*)page);
if (length >= 0)
length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
free_page(page);
out:
put_task_struct(task);
out_no_task:
return length;
}
static const struct file_operations proc_info_file_operations = {
.read = proc_info_read,
};
static int mem_open(struct inode* inode, struct file* file)
{
file->private_data = (void*)((long)current->self_exec_id);
return 0;
}
static ssize_t mem_read(struct file * file, char __user * buf,
size_t count, loff_t *ppos)
{
struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
char *page;
unsigned long src = *ppos;
int ret = -ESRCH;
struct mm_struct *mm;
if (!task)
goto out_no_task;
if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
goto out;
ret = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
goto out;
ret = 0;
mm = get_task_mm(task);
if (!mm)
goto out_free;
ret = -EIO;
if (file->private_data != (void*)((long)current->self_exec_id))
goto out_put;
ret = 0;
while (count > 0) {
int this_len, retval;
this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
retval = access_process_vm(task, src, page, this_len, 0);
if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
if (!ret)
ret = -EIO;
break;
}
if (copy_to_user(buf, page, retval)) {
ret = -EFAULT;
break;
}
ret += retval;
src += retval;
buf += retval;
count -= retval;
}
*ppos = src;
out_put:
mmput(mm);
out_free:
free_page((unsigned long) page);
out:
put_task_struct(task);
out_no_task:
return ret;
}
#define mem_write NULL
#ifndef mem_write
/* This is a security hazard */
static ssize_t mem_write(struct file * file, const char __user *buf,
size_t count, loff_t *ppos)
{
int copied;
char *page;
struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
unsigned long dst = *ppos;
copied = -ESRCH;
if (!task)
goto out_no_task;
if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
goto out;
copied = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
goto out;
copied = 0;
while (count > 0) {
int this_len, retval;
this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
if (copy_from_user(page, buf, this_len)) {
copied = -EFAULT;
break;
}
retval = access_process_vm(task, dst, page, this_len, 1);
if (!retval) {
if (!copied)
copied = -EIO;
break;
}
copied += retval;
buf += retval;
dst += retval;
count -= retval;
}
*ppos = dst;
free_page((unsigned long) page);
out:
put_task_struct(task);
out_no_task:
return copied;
}
#endif
static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
{
switch (orig) {
case 0:
file->f_pos = offset;
break;
case 1:
file->f_pos += offset;
break;
default:
return -EINVAL;
}
force_successful_syscall_return();
return file->f_pos;
}
static const struct file_operations proc_mem_operations = {
.llseek = mem_lseek,
.read = mem_read,
.write = mem_write,
.open = mem_open,
};
static ssize_t environ_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
char *page;
unsigned long src = *ppos;
int ret = -ESRCH;
struct mm_struct *mm;
if (!task)
goto out_no_task;
if (!ptrace_may_attach(task))
goto out;
ret = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
goto out;
ret = 0;
mm = get_task_mm(task);
if (!mm)
goto out_free;
while (count > 0) {
int this_len, retval, max_len;
this_len = mm->env_end - (mm->env_start + src);
if (this_len <= 0)
break;
max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
this_len = (this_len > max_len) ? max_len : this_len;
retval = access_process_vm(task, (mm->env_start + src),
page, this_len, 0);
if (retval <= 0) {
ret = retval;
break;
}
if (copy_to_user(buf, page, retval)) {
ret = -EFAULT;
break;
}
ret += retval;
src += retval;
buf += retval;
count -= retval;
}
*ppos = src;
mmput(mm);
out_free:
free_page((unsigned long) page);
out:
put_task_struct(task);
out_no_task:
return ret;
}
static const struct file_operations proc_environ_operations = {
.read = environ_read,
};
static ssize_t oom_adjust_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
char buffer[PROC_NUMBUF];
size_t len;
int oom_adjust;
if (!task)
return -ESRCH;
oom_adjust = task->oomkilladj;
put_task_struct(task);
len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF], *end;
int oom_adjust;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
oom_adjust = simple_strtol(buffer, &end, 0);
if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
oom_adjust != OOM_DISABLE)
return -EINVAL;
if (*end == '\n')
end++;
task = get_proc_task(file->f_path.dentry->d_inode);
if (!task)
return -ESRCH;
if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) {
put_task_struct(task);
return -EACCES;
}
task->oomkilladj = oom_adjust;
put_task_struct(task);
if (end - buffer == 0)
return -EIO;
return end - buffer;
}
static const struct file_operations proc_oom_adjust_operations = {
.read = oom_adjust_read,
.write = oom_adjust_write,
};
#ifdef CONFIG_MMU
static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF], *end;
struct mm_struct *mm;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
if (!simple_strtol(buffer, &end, 0))
return -EINVAL;
if (*end == '\n')
end++;
task = get_proc_task(file->f_path.dentry->d_inode);
if (!task)
return -ESRCH;
mm = get_task_mm(task);
if (mm) {
clear_refs_smap(mm);
mmput(mm);
}
put_task_struct(task);
if (end - buffer == 0)
return -EIO;
return end - buffer;
}
static struct file_operations proc_clear_refs_operations = {
.write = clear_refs_write,
};
#endif
#ifdef CONFIG_AUDITSYSCALL
#define TMPBUFLEN 21
static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
size_t count, loff_t *ppos)
{
struct inode * inode = file->f_path.dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
ssize_t length;
char tmpbuf[TMPBUFLEN];
if (!task)
return -ESRCH;
length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
audit_get_loginuid(task->audit_context));
put_task_struct(task);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
size_t count, loff_t *ppos)
{
struct inode * inode = file->f_path.dentry->d_inode;
char *page, *tmp;
ssize_t length;
uid_t loginuid;
if (!capable(CAP_AUDIT_CONTROL))
return -EPERM;
if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
return -EPERM;
if (count >= PAGE_SIZE)
count = PAGE_SIZE - 1;
if (*ppos != 0) {
/* No partial writes. */
return -EINVAL;
}
page = (char*)__get_free_page(GFP_TEMPORARY);
if (!page)
return -ENOMEM;
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out_free_page;
page[count] = '\0';
loginuid = simple_strtoul(page, &tmp, 10);
if (tmp == page) {
length = -EINVAL;
goto out_free_page;
}
length = audit_set_loginuid(current, loginuid);
if (likely(length == 0))
length = count;
out_free_page:
free_page((unsigned long) page);
return length;
}
static const struct file_operations proc_loginuid_operations = {
.read = proc_loginuid_read,
.write = proc_loginuid_write,
};
#endif
#ifdef CONFIG_FAULT_INJECTION
static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
size_t count, loff_t *ppos)
{
struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
char buffer[PROC_NUMBUF];
size_t len;
int make_it_fail;
if (!task)
return -ESRCH;
make_it_fail = task->make_it_fail;
put_task_struct(task);
len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
static ssize_t proc_fault_inject_write(struct file * file,
const char __user * buf, size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF], *end;
int make_it_fail;
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
make_it_fail = simple_strtol(buffer, &end, 0);
if (*end == '\n')
end++;
task = get_proc_task(file->f_dentry->d_inode);
if (!task)
return -ESRCH;
task->make_it_fail = make_it_fail;
put_task_struct(task);
if (end - buffer == 0)
return -EIO;
return end - buffer;
}
static const struct file_operations proc_fault_inject_operations = {
.read = proc_fault_inject_read,
.write = proc_fault_inject_write,
};
#endif
#ifdef CONFIG_SCHED_DEBUG
/*
* Print out various scheduling related per-task fields:
*/
static int sched_show(struct seq_file *m, void *v)
{
struct inode *inode = m->private;
struct task_struct *p;
WARN_ON(!inode);
p = get_proc_task(inode);
if (!p)
return -ESRCH;
proc_sched_show_task(p, m);
put_task_struct(p);
return 0;
}
static ssize_t
sched_write(struct file *file, const char __user *buf,
size_t count, loff_t *offset)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct task_struct *p;
WARN_ON(!inode);
p = get_proc_task(inode);
if (!p)
return -ESRCH;
proc_sched_set_task(p);
put_task_struct(p);
return count;
}
static int sched_open(struct inode *inode, struct file *filp)
{
int ret;
ret = single_open(filp, sched_show, NULL);
if (!ret) {
struct seq_file *m = filp->private_data;
m->private = inode;
}
return ret;
}
static const struct file_operations proc_pid_sched_operations = {
.open = sched_open,
.read = seq_read,
.write = sched_write,
.llseek = seq_lseek,
.release = single_release,
};
#endif
static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
int error = -EACCES;
/* We don't need a base pointer in the /proc filesystem */
path_release(nd);
/* Are we allowed to snoop on the tasks file descriptors? */
if (!proc_fd_access_allowed(inode))
goto out;
error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
nd->last_type = LAST_BIND;
out:
return ERR_PTR(error);
}
static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
char __user *buffer, int buflen)
{
struct inode * inode;
char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
char *path;
int len;
if (!tmp)
return -ENOMEM;
inode = dentry->d_inode;
path = d_path(dentry, mnt, tmp, PAGE_SIZE);
len = PTR_ERR(path);
if (IS_ERR(path))
goto out;
len = tmp + PAGE_SIZE - 1 - path;
if (len > buflen)
len = buflen;
if (copy_to_user(buffer, path, len))
len = -EFAULT;
out:
free_page((unsigned long)tmp);
return len;
}
static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
{
int error = -EACCES;
struct inode *inode = dentry->d_inode;
struct dentry *de;
struct vfsmount *mnt = NULL;
/* Are we allowed to snoop on the tasks file descriptors? */
if (!proc_fd_access_allowed(inode))
goto out;
error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
if (error)
goto out;
error = do_proc_readlink(de, mnt, buffer, buflen);
dput(de);
mntput(mnt);
out:
return error;
}
static const struct inode_operations proc_pid_link_inode_operations = {
.readlink = proc_pid_readlink,
.follow_link = proc_pid_follow_link,
.setattr = proc_setattr,
};
/* building an inode */
static int task_dumpable(struct task_struct *task)
{
int dumpable = 0;
struct mm_struct *mm;
task_lock(task);
mm = task->mm;
if (mm)
dumpable = get_dumpable(mm);
task_unlock(task);
if(dumpable == 1)
return 1;
return 0;
}
static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
{
struct inode * inode;
struct proc_inode *ei;
/* We need a new inode */
inode = new_inode(sb);
if (!inode)
goto out;
/* Common stuff */
ei = PROC_I(inode);
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_op = &proc_def_inode_operations;
/*
* grab the reference to task.
*/
ei->pid = get_task_pid(task, PIDTYPE_PID);
if (!ei->pid)
goto out_unlock;
inode->i_uid = 0;
inode->i_gid = 0;
if (task_dumpable(task)) {
inode->i_uid = task->euid;
inode->i_gid = task->egid;
}
security_task_to_inode(task, inode);
out:
return inode;
out_unlock:
iput(inode);
return NULL;
}
static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
struct task_struct *task;
generic_fillattr(inode, stat);
rcu_read_lock();
stat->uid = 0;
stat->gid = 0;
task = pid_task(proc_pid(inode), PIDTYPE_PID);
if (task) {
if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
task_dumpable(task)) {
stat->uid = task->euid;
stat->gid = task->egid;
}
}
rcu_read_unlock();
return 0;
}
/* dentry stuff */
/*
* Exceptional case: normally we are not allowed to unhash a busy
* directory. In this case, however, we can do it - no aliasing problems
* due to the way we treat inodes.
*
* Rewrite the inode's ownerships here because the owning task may have
* performed a setuid(), etc.
*
* Before the /proc/pid/status file was created the only way to read
* the effective uid of a /process was to stat /proc/pid. Reading
* /proc/pid/status is slow enough that procps and other packages
* kept stating /proc/pid. To keep the rules in /proc simple I have
* made this apply to all per process world readable and executable
* directories.
*/
static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
if (task) {
if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
task_dumpable(task)) {
inode->i_uid = task->euid;
inode->i_gid = task->egid;
} else {
inode->i_uid = 0;
inode->i_gid = 0;
}
inode->i_mode &= ~(S_ISUID | S_ISGID);
security_task_to_inode(task, inode);
put_task_struct(task);
return 1;
}
d_drop(dentry);
return 0;
}
static int pid_delete_dentry(struct dentry * dentry)
{
/* Is the task we represent dead?
* If so, then don't put the dentry on the lru list,
* kill it immediately.
*/
return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
}
static struct dentry_operations pid_dentry_operations =
{
.d_revalidate = pid_revalidate,
.d_delete = pid_delete_dentry,
};
/* Lookups */
typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
struct task_struct *, const void *);
/*
* Fill a directory entry.
*
* If possible create the dcache entry and derive our inode number and
* file type from dcache entry.
*
* Since all of the proc inode numbers are dynamically generated, the inode
* numbers do not exist until the inode is cache. This means creating the
* the dcache entry in readdir is necessary to keep the inode numbers
* reported by readdir in sync with the inode numbers reported
* by stat.
*/
static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
char *name, int len,
instantiate_t instantiate, struct task_struct *task, const void *ptr)
{
struct dentry *child, *dir = filp->f_path.dentry;
struct inode *inode;
struct qstr qname;
ino_t ino = 0;
unsigned type = DT_UNKNOWN;
qname.name = name;
qname.len = len;
qname.hash = full_name_hash(name, len);
child = d_lookup(dir, &qname);
if (!child) {
struct dentry *new;
new = d_alloc(dir, &qname);
if (new) {
child = instantiate(dir->d_inode, new, task, ptr);
if (child)
dput(new);
else
child = new;
}
}
if (!child || IS_ERR(child) || !child->d_inode)
goto end_instantiate;
inode = child->d_inode;
if (inode) {
ino = inode->i_ino;
type = inode->i_mode >> 12;
}
dput(child);
end_instantiate:
if (!ino)
ino = find_inode_number(dir, &qname);
if (!ino)
ino = 1;
return filldir(dirent, name, len, filp->f_pos, ino, type);
}
static unsigned name_to_int(struct dentry *dentry)
{
const char *name = dentry->d_name.name;
int len = dentry->d_name.len;
unsigned n = 0;
if (len > 1 && *name == '0')
goto out;
while (len-- > 0) {
unsigned c = *name++ - '0';
if (c > 9)
goto out;
if (n >= (~0U-9)/10)
goto out;
n *= 10;
n += c;
}
return n;
out:
return ~0U;
}
#define PROC_FDINFO_MAX 64
static int proc_fd_info(struct inode *inode, struct dentry **dentry,
struct vfsmount **mnt, char *info)
{
struct task_struct *task = get_proc_task(inode);
struct files_struct *files = NULL;
struct file *file;
int fd = proc_fd(inode);
if (task) {
files = get_files_struct(task);
put_task_struct(task);
}
if (files) {
/*
* We are not taking a ref to the file structure, so we must
* hold ->file_lock.
*/
spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (file) {
if (mnt)
*mnt = mntget(file->f_path.mnt);
if (dentry)
*dentry = dget(file->f_path.dentry);
if (info)
snprintf(info, PROC_FDINFO_MAX,
"pos:\t%lli\n"
"flags:\t0%o\n",
(long long) file->f_pos,
file->f_flags);
spin_unlock(&files->file_lock);
put_files_struct(files);
return 0;
}
spin_unlock(&files->file_lock);
put_files_struct(files);
}
return -ENOENT;
}
static int proc_fd_link(struct inode *inode, struct dentry **dentry,
struct vfsmount **mnt)
{
return proc_fd_info(inode, dentry, mnt, NULL);
}
static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
int fd = proc_fd(inode);
struct files_struct *files;
if (task) {
files = get_files_struct(task);
if (files) {
rcu_read_lock();
if (fcheck_files(files, fd)) {
rcu_read_unlock();
put_files_struct(files);
if (task_dumpable(task)) {
inode->i_uid = task->euid;
inode->i_gid = task->egid;
} else {
inode->i_uid = 0;
inode->i_gid = 0;
}
inode->i_mode &= ~(S_ISUID | S_ISGID);
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 struct dentry_operations tid_fd_dentry_operations =
{
.d_revalidate = tid_fd_revalidate,
.d_delete = pid_delete_dentry,
};
static struct dentry *proc_fd_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
unsigned fd = *(const unsigned *)ptr;
struct file *file;
struct files_struct *files;
struct inode *inode;
struct proc_inode *ei;
struct dentry *error = ERR_PTR(-ENOENT);
inode = proc_pid_make_inode(dir->i_sb, task);
if (!inode)
goto out;
ei = PROC_I(inode);
ei->fd = fd;
files = get_files_struct(task);
if (!files)
goto out_iput;
inode->i_mode = S_IFLNK;
/*
* We are not taking a ref to the file structure, so we must
* hold ->file_lock.
*/
spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (!file)
goto out_unlock;
if (file->f_mode & 1)
inode->i_mode |= S_IRUSR | S_IXUSR;
if (file->f_mode & 2)
inode->i_mode |= S_IWUSR | S_IXUSR;
spin_unlock(&files->file_lock);
put_files_struct(files);
inode->i_op = &proc_pid_link_inode_operations;
inode->i_size = 64;
ei->op.proc_get_link = proc_fd_link;
dentry->d_op = &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, NULL))
error = NULL;
out:
return error;
out_unlock:
spin_unlock(&files->file_lock);
put_files_struct(files);
out_iput:
iput(inode);
goto out;
}
static struct dentry *proc_lookupfd_common(struct inode *dir,
struct dentry *dentry,
instantiate_t instantiate)
{
struct task_struct *task = get_proc_task(dir);
unsigned fd = name_to_int(dentry);
struct dentry *result = ERR_PTR(-ENOENT);
if (!task)
goto out_no_task;
if (fd == ~0U)
goto out;
result = instantiate(dir, dentry, task, &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);
unsigned int fd, ino;
int retval;
struct files_struct * files;
struct fdtable *fdt;
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();
fdt = files_fdtable(files);
for (fd = filp->f_pos-2;
fd < fdt->max_fds;
fd++, filp->f_pos++) {
char name[PROC_NUMBUF];
int len;
if (!fcheck_files(files, fd))
continue;
rcu_read_unlock();
len = snprintf(name, sizeof(name), "%d", fd);
if (proc_fill_cache(filp, dirent, filldir,
name, len, instantiate,
p, &fd) < 0) {
rcu_read_lock();
break;
}
rcu_read_lock();
}
rcu_read_unlock();
put_files_struct(files);
}
out:
put_task_struct(p);
out_no_task:
return retval;
}
static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
}
static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
{
return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
}
static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
char tmp[PROC_FDINFO_MAX];
int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, NULL, tmp);
if (!err)
err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
return err;
}
static const struct file_operations proc_fdinfo_file_operations = {
.open = nonseekable_open,
.read = proc_fdinfo_read,
};
static const struct file_operations proc_fd_operations = {
.read = generic_read_dir,
.readdir = proc_readfd,
};
/*
* /proc/pid/fd needs a special permission handler so that a process can still
* access /proc/self/fd after it has executed a setuid().
*/
static int proc_fd_permission(struct inode *inode, int mask,
struct nameidata *nd)
{
int rv;
rv = generic_permission(inode, mask, NULL);
if (rv == 0)
return 0;
if (task_pid(current) == proc_pid(inode))
rv = 0;
return rv;
}
/*
* proc directories can do almost nothing..
*/
static 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)
{
unsigned fd = *(unsigned *)ptr;
struct inode *inode;
struct proc_inode *ei;
struct dentry *error = ERR_PTR(-ENOENT);
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;
dentry->d_op = &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, NULL))
error = NULL;
out:
return error;
}
static struct dentry *proc_lookupfdinfo(struct inode *dir,
struct dentry *dentry,
struct nameidata *nd)
{
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);
}
static const struct file_operations proc_fdinfo_operations = {
.read = generic_read_dir,
.readdir = proc_readfdinfo,
};
/*
* proc directories can do almost nothing..
*/
static const struct inode_operations proc_fdinfo_inode_operations = {
.lookup = proc_lookupfdinfo,
.setattr = proc_setattr,
};
static struct dentry *proc_pident_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 = ERR_PTR(-EINVAL);
inode = proc_pid_make_inode(dir->i_sb, task);
if (!inode)
goto out;
ei = PROC_I(inode);
inode->i_mode = p->mode;
if (S_ISDIR(inode->i_mode))
inode->i_nlink = 2; /* Use getattr to fix if necessary */
if (p->iop)
inode->i_op = p->iop;
if (p->fop)
inode->i_fop = p->fop;
ei->op = p->op;
dentry->d_op = &pid_dentry_operations;
d_add(dentry, inode);
/* Close the race of the process dying before we return the dentry */
if (pid_revalidate(dentry, NULL))
error = NULL;
out:
return error;
}
static struct dentry *proc_pident_lookup(struct inode *dir,
struct dentry *dentry,
const struct pid_entry *ents,
unsigned int nents)
{
struct inode *inode;
struct dentry *error;
struct task_struct *task = get_proc_task(dir);
const struct pid_entry *p, *last;
error = ERR_PTR(-ENOENT);
inode = NULL;
if (!task)
goto out_no_task;
/*
* Yes, it does not scale. And it should not. Don't add
* new entries into /proc/<tgid>/ without very good reasons.
*/
last = &ents[nents - 1];
for (p = ents; 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_pident_instantiate(dir, dentry, task, p);
out:
put_task_struct(task);
out_no_task:
return error;
}
static int proc_pident_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_pident_instantiate, task, p);
}
static int proc_pident_readdir(struct file *filp,
void *dirent, filldir_t filldir,
const struct pid_entry *ents, unsigned int nents)
{
int i;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
const struct pid_entry *p, *last;
ino_t ino;
int ret;
ret = -ENOENT;
if (!task)
goto out_no_task;
ret = 0;
i = filp->f_pos;
switch (i) {
case 0:
ino = inode->i_ino;
if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
goto out;
i++;
filp->f_pos++;
/* fall through */
case 1:
ino = parent_ino(dentry);
if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
goto out;
i++;
filp->f_pos++;
/* fall through */
default:
i -= 2;
if (i >= nents) {
ret = 1;
goto out;
}
p = ents + i;
last = &ents[nents - 1];
while (p <= last) {
if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
goto out;
filp->f_pos++;
p++;
}
}
ret = 1;
out:
put_task_struct(task);
out_no_task:
return ret;
}
#ifdef CONFIG_SECURITY
static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
size_t count, loff_t *ppos)
{
struct inode * inode = file->f_path.dentry->d_inode;
char *p = NULL;
ssize_t length;
struct task_struct *task = get_proc_task(inode);
if (!task)
return -ESRCH;
length = security_getprocattr(task,
(char*)file->f_path.dentry->d_name.name,
&p);
put_task_struct(task);
if (length > 0)
length = simple_read_from_buffer(buf, count, ppos, p, length);
kfree(p);
return length;
}
static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
size_t count, loff_t *ppos)
{
struct inode * inode = file->f_path.dentry->d_inode;
char *page;
ssize_t length;
struct task_struct *task = get_proc_task(inode);
length = -ESRCH;
if (!task)
goto out_no_task;
if (count > PAGE_SIZE)
count = PAGE_SIZE;
/* No partial writes. */
length = -EINVAL;
if (*ppos != 0)
goto out;
length = -ENOMEM;
page = (char*)__get_free_page(GFP_TEMPORARY);
if (!page)
goto out;
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out_free;
length = security_setprocattr(task,
(char*)file->f_path.dentry->d_name.name,
(void*)page, count);
out_free:
free_page((unsigned long) page);
out:
put_task_struct(task);
out_no_task:
return length;
}
static const struct file_operations proc_pid_attr_operations = {
.read = proc_pid_attr_read,
.write = proc_pid_attr_write,
};
static const struct pid_entry attr_dir_stuff[] = {
REG("current", S_IRUGO|S_IWUGO, pid_attr),
REG("prev", S_IRUGO, pid_attr),
REG("exec", S_IRUGO|S_IWUGO, pid_attr),
REG("fscreate", S_IRUGO|S_IWUGO, pid_attr),
REG("keycreate", S_IRUGO|S_IWUGO, pid_attr),
REG("sockcreate", S_IRUGO|S_IWUGO, pid_attr),
};
static int proc_attr_dir_readdir(struct file * filp,
void * dirent, filldir_t filldir)
{
return proc_pident_readdir(filp,dirent,filldir,
attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
}
static const struct file_operations proc_attr_dir_operations = {
.read = generic_read_dir,
.readdir = proc_attr_dir_readdir,
};
static struct dentry *proc_attr_dir_lookup(struct inode *dir,
struct dentry *dentry, struct nameidata *nd)
{
return proc_pident_lookup(dir, dentry,
attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
}
static const struct inode_operations proc_attr_dir_inode_operations = {
.lookup = proc_attr_dir_lookup,
.getattr = pid_getattr,
.setattr = proc_setattr,
};
#endif
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
struct mm_struct *mm;
char buffer[PROC_NUMBUF];
size_t len;
int ret;
if (!task)
return -ESRCH;
ret = 0;
mm = get_task_mm(task);
if (mm) {
len = snprintf(buffer, sizeof(buffer), "%08lx\n",
((mm->flags & MMF_DUMP_FILTER_MASK) >>
MMF_DUMP_FILTER_SHIFT));
mmput(mm);
ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
}
put_task_struct(task);
return ret;
}
static ssize_t proc_coredump_filter_write(struct file *file,
const char __user *buf,
size_t count,
loff_t *ppos)
{
struct task_struct *task;
struct mm_struct *mm;
char buffer[PROC_NUMBUF], *end;
unsigned int val;
int ret;
int i;
unsigned long mask;
ret = -EFAULT;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
goto out_no_task;
ret = -EINVAL;
val = (unsigned int)simple_strtoul(buffer, &end, 0);
if (*end == '\n')
end++;
if (end - buffer == 0)
goto out_no_task;
ret = -ESRCH;
task = get_proc_task(file->f_dentry->d_inode);
if (!task)
goto out_no_task;
ret = end - buffer;
mm = get_task_mm(task);
if (!mm)
goto out_no_mm;
for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
if (val & mask)
set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
else
clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
}
mmput(mm);
out_no_mm:
put_task_struct(task);
out_no_task:
return ret;
}
static const struct file_operations proc_coredump_filter_operations = {
.read = proc_coredump_filter_read,
.write = proc_coredump_filter_write,
};
#endif
/*
* /proc/self:
*/
static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
int buflen)
{
char tmp[PROC_NUMBUF];
sprintf(tmp, "%d", task_tgid_vnr(current));
return vfs_readlink(dentry,buffer,buflen,tmp);
}
static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
{
char tmp[PROC_NUMBUF];
sprintf(tmp, "%d", task_tgid_vnr(current));
return ERR_PTR(vfs_follow_link(nd,tmp));
}
static const struct inode_operations proc_self_inode_operations = {
.readlink = proc_self_readlink,
.follow_link = proc_self_follow_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, {}),
};
/*
* Exceptional case: normally we are not allowed to unhash a busy
* directory. In this case, however, we can do it - no aliasing problems
* due to the way we treat inodes.
*/
static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
if (task) {
put_task_struct(task);
return 1;
}
d_drop(dentry);
return 0;
}
static struct dentry_operations proc_base_dentry_operations =
{
.d_revalidate = proc_base_revalidate,
.d_delete = pid_delete_dentry,
};
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 = ERR_PTR(-EINVAL);
/* 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_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_uid = 0;
inode->i_gid = 0;
inode->i_mode = p->mode;
if (S_ISDIR(inode->i_mode))
inode->i_nlink = 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;
dentry->d_op = &proc_base_dentry_operations;
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 proc_pid_io_accounting(struct task_struct *task, char *buffer)
{
return sprintf(buffer,
#ifdef CONFIG_TASK_XACCT
"rchar: %llu\n"
"wchar: %llu\n"
"syscr: %llu\n"
"syscw: %llu\n"
#endif
"read_bytes: %llu\n"
"write_bytes: %llu\n"
"cancelled_write_bytes: %llu\n",
#ifdef CONFIG_TASK_XACCT
(unsigned long long)task->rchar,
(unsigned long long)task->wchar,
(unsigned long long)task->syscr,
(unsigned long long)task->syscw,
#endif
(unsigned long long)task->ioac.read_bytes,
(unsigned long long)task->ioac.write_bytes,
(unsigned long long)task->ioac.cancelled_write_bytes);
}
#endif
/*
* Thread groups
*/
static const struct file_operations proc_task_operations;
static const struct inode_operations proc_task_inode_operations;
static const struct pid_entry tgid_base_stuff[] = {
DIR("task", S_IRUGO|S_IXUGO, task),
DIR("fd", S_IRUSR|S_IXUSR, fd),
DIR("fdinfo", S_IRUSR|S_IXUSR, fdinfo),
REG("environ", S_IRUSR, environ),
INF("auxv", S_IRUSR, pid_auxv),
INF("status", S_IRUGO, pid_status),
INF("limits", S_IRUSR, pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, pid_sched),
#endif
INF("cmdline", S_IRUGO, pid_cmdline),
INF("stat", S_IRUGO, tgid_stat),
INF("statm", S_IRUGO, pid_statm),
REG("maps", S_IRUGO, maps),
#ifdef CONFIG_NUMA
REG("numa_maps", S_IRUGO, numa_maps),
#endif
REG("mem", S_IRUSR|S_IWUSR, mem),
LNK("cwd", cwd),
LNK("root", root),
LNK("exe", exe),
REG("mounts", S_IRUGO, mounts),
REG("mountstats", S_IRUSR, mountstats),
#ifdef CONFIG_MMU
REG("clear_refs", S_IWUSR, clear_refs),
REG("smaps", S_IRUGO, smaps),
#endif
#ifdef CONFIG_SECURITY
DIR("attr", S_IRUGO|S_IXUGO, attr_dir),
#endif
#ifdef CONFIG_KALLSYMS
INF("wchan", S_IRUGO, pid_wchan),
#endif
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, pid_schedstat),
#endif
#ifdef CONFIG_PROC_PID_CPUSET
REG("cpuset", S_IRUGO, cpuset),
#endif
#ifdef CONFIG_CGROUPS
REG("cgroup", S_IRUGO, cgroup),
#endif
INF("oom_score", S_IRUGO, oom_score),
REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
#ifdef CONFIG_AUDITSYSCALL
REG("loginuid", S_IWUSR|S_IRUGO, loginuid),
#endif
#ifdef CONFIG_FAULT_INJECTION
REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
#endif
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
REG("coredump_filter", S_IRUGO|S_IWUSR, coredump_filter),
#endif
#ifdef CONFIG_TASK_IO_ACCOUNTING
INF("io", S_IRUGO, pid_io_accounting),
#endif
};
static int proc_tgid_base_readdir(struct file * filp,
void * dirent, filldir_t filldir)
{
return proc_pident_readdir(filp,dirent,filldir,
tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
}
static const struct file_operations proc_tgid_base_operations = {
.read = generic_read_dir,
.readdir = proc_tgid_base_readdir,
};
static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
return proc_pident_lookup(dir, dentry,
tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
}
static const struct inode_operations proc_tgid_base_inode_operations = {
.lookup = proc_tgid_base_lookup,
.getattr = pid_getattr,
.setattr = proc_setattr,
};
static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
{
struct dentry *dentry, *leader, *dir;
char buf[PROC_NUMBUF];
struct qstr name;
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", pid);
dentry = d_hash_and_lookup(mnt->mnt_root, &name);
if (dentry) {
shrink_dcache_parent(dentry);
d_drop(dentry);
dput(dentry);
}
if (tgid == 0)
goto out;
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", tgid);
leader = d_hash_and_lookup(mnt->mnt_root, &name);
if (!leader)
goto out;
name.name = "task";
name.len = strlen(name.name);
dir = d_hash_and_lookup(leader, &name);
if (!dir)
goto out_put_leader;
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", pid);
dentry = d_hash_and_lookup(dir, &name);
if (dentry) {
shrink_dcache_parent(dentry);
d_drop(dentry);
dput(dentry);
}
dput(dir);
out_put_leader:
dput(leader);
out:
return;
}
/**
* proc_flush_task - Remove dcache entries for @task from the /proc dcache.
* @task: task that should be flushed.
*
* When flushing dentries from proc, one needs to flush them from global
* proc (proc_mnt) and from all the namespaces' procs this task was seen
* in. This call is supposed to do all of this job.
*
* Looks in the dcache for
* /proc/@pid
* /proc/@tgid/task/@pid
* if either directory is present flushes it and all of it'ts children
* from the dcache.
*
* It is safe and reasonable to cache /proc entries for a task until
* that task exits. After that they just clog up the dcache with
* useless entries, possibly causing useful dcache entries to be
* flushed instead. This routine is proved to flush those useless
* dcache entries at process exit time.
*
* NOTE: This routine is just an optimization so it does not guarantee
* that no dcache entries will exist at process exit time it
* just makes it very unlikely that any will persist.
*/
void proc_flush_task(struct task_struct *task)
{
int i;
struct pid *pid, *tgid = NULL;
struct upid *upid;
pid = task_pid(task);
if (thread_group_leader(task))
tgid = task_tgid(task);
for (i = 0; i <= pid->level; i++) {
upid = &pid->numbers[i];
proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
tgid ? tgid->numbers[i].nr : 0);
}
upid = &pid->numbers[pid->level];
if (upid->nr == 1)
pid_ns_release_proc(upid->ns);
}
static struct dentry *proc_pid_instantiate(struct inode *dir,
struct dentry * dentry,
struct task_struct *task, const void *ptr)
{
struct dentry *error = ERR_PTR(-ENOENT);
struct inode *inode;
inode = proc_pid_make_inode(dir->i_sb, task);
if (!inode)
goto out;
inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
inode->i_op = &proc_tgid_base_inode_operations;
inode->i_fop = &proc_tgid_base_operations;
inode->i_flags|=S_IMMUTABLE;
inode->i_nlink = 5;
#ifdef CONFIG_SECURITY
inode->i_nlink += 1;
#endif
dentry->d_op = &pid_dentry_operations;
d_add(dentry, inode);
/* Close the race of the process dying before we return the dentry */
if (pid_revalidate(dentry, NULL))
error = NULL;
out:
return error;
}
struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
struct dentry *result = ERR_PTR(-ENOENT);
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;
ns = dentry->d_sb->s_fs_info;
rcu_read_lock();
task = find_task_by_pid_ns(tgid, ns);
if (task)
get_task_struct(task);
rcu_read_unlock();
if (!task)
goto out;
result = proc_pid_instantiate(dir, dentry, task, NULL);
put_task_struct(task);
out:
return result;
}
/*
* Find the first task with tgid >= tgid
*
*/
struct tgid_iter {
unsigned int tgid;
struct task_struct *task;
};
static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
{
struct pid *pid;
if (iter.task)
put_task_struct(iter.task);
rcu_read_lock();
retry:
iter.task = NULL;
pid = find_ge_pid(iter.tgid, ns);
if (pid) {
iter.tgid = pid_nr_ns(pid, ns);
iter.task = pid_task(pid, PIDTYPE_PID);
/* What we to know is if the pid we have find is the
* pid of a thread_group_leader. Testing for task
* being a thread_group_leader is the obvious thing
* todo but there is a window when it fails, due to
* the pid transfer logic in de_thread.
*
* So we perform the straight forward test of seeing
* if the pid we have found is the pid of a thread
* group leader, and don't worry if the task we have
* found doesn't happen to be a thread group leader.
* As we don't care in the case of readdir.
*/
if (!iter.task || !has_group_leader_pid(iter.task)) {
iter.tgid += 1;
goto retry;
}
get_task_struct(iter.task);
}
rcu_read_unlock();
return iter;
}
#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct tgid_iter iter)
{
char name[PROC_NUMBUF];
int len = snprintf(name, sizeof(name), "%d", iter.tgid);
return proc_fill_cache(filp, dirent, filldir, name, len,
proc_pid_instantiate, iter.task, NULL);
}
/* for the /proc/ directory itself, after non-process stuff has been done */
int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
struct task_struct *reaper = get_proc_task(filp->f_path.dentry->d_inode);
struct tgid_iter iter;
struct pid_namespace *ns;
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;
for (iter = next_tgid(ns, iter);
iter.task;
iter.tgid += 1, iter = next_tgid(ns, iter)) {
filp->f_pos = iter.tgid + TGID_OFFSET;
if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
put_task_struct(iter.task);
goto out;
}
}
filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
out:
put_task_struct(reaper);
out_no_task:
return 0;
}
/*
* Tasks
*/
static const struct pid_entry tid_base_stuff[] = {
DIR("fd", S_IRUSR|S_IXUSR, fd),
DIR("fdinfo", S_IRUSR|S_IXUSR, fdinfo),
REG("environ", S_IRUSR, environ),
INF("auxv", S_IRUSR, pid_auxv),
INF("status", S_IRUGO, pid_status),
INF("limits", S_IRUSR, pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, pid_sched),
#endif
INF("cmdline", S_IRUGO, pid_cmdline),
INF("stat", S_IRUGO, tid_stat),
INF("statm", S_IRUGO, pid_statm),
REG("maps", S_IRUGO, maps),
#ifdef CONFIG_NUMA
REG("numa_maps", S_IRUGO, numa_maps),
#endif
REG("mem", S_IRUSR|S_IWUSR, mem),
LNK("cwd", cwd),
LNK("root", root),
LNK("exe", exe),
REG("mounts", S_IRUGO, mounts),
#ifdef CONFIG_MMU
REG("clear_refs", S_IWUSR, clear_refs),
REG("smaps", S_IRUGO, smaps),
#endif
#ifdef CONFIG_SECURITY
DIR("attr", S_IRUGO|S_IXUGO, attr_dir),
#endif
#ifdef CONFIG_KALLSYMS
INF("wchan", S_IRUGO, pid_wchan),
#endif
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, pid_schedstat),
#endif
#ifdef CONFIG_PROC_PID_CPUSET
REG("cpuset", S_IRUGO, cpuset),
#endif
#ifdef CONFIG_CGROUPS
REG("cgroup", S_IRUGO, cgroup),
#endif
INF("oom_score", S_IRUGO, oom_score),
REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
#ifdef CONFIG_AUDITSYSCALL
REG("loginuid", S_IWUSR|S_IRUGO, loginuid),
#endif
#ifdef CONFIG_FAULT_INJECTION
REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
#endif
};
static int proc_tid_base_readdir(struct file * filp,
void * dirent, filldir_t filldir)
{
return proc_pident_readdir(filp,dirent,filldir,
tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
}
static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
return proc_pident_lookup(dir, dentry,
tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
}
static const struct file_operations proc_tid_base_operations = {
.read = generic_read_dir,
.readdir = proc_tid_base_readdir,
};
static const struct inode_operations proc_tid_base_inode_operations = {
.lookup = proc_tid_base_lookup,
.getattr = pid_getattr,
.setattr = proc_setattr,
};
static struct dentry *proc_task_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
struct dentry *error = ERR_PTR(-ENOENT);
struct inode *inode;
inode = proc_pid_make_inode(dir->i_sb, task);
if (!inode)
goto out;
inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
inode->i_op = &proc_tid_base_inode_operations;
inode->i_fop = &proc_tid_base_operations;
inode->i_flags|=S_IMMUTABLE;
inode->i_nlink = 4;
#ifdef CONFIG_SECURITY
inode->i_nlink += 1;
#endif
dentry->d_op = &pid_dentry_operations;
d_add(dentry, inode);
/* Close the race of the process dying before we return the dentry */
if (pid_revalidate(dentry, NULL))
error = NULL;
out:
return error;
}
static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
struct dentry *result = ERR_PTR(-ENOENT);
struct task_struct *task;
struct task_struct *leader = get_proc_task(dir);
unsigned tid;
struct pid_namespace *ns;
if (!leader)
goto out_no_task;
tid = name_to_int(dentry);
if (tid == ~0U)
goto out;
ns = dentry->d_sb->s_fs_info;
rcu_read_lock();
task = find_task_by_pid_ns(tid, ns);
if (task)
get_task_struct(task);
rcu_read_unlock();
if (!task)
goto out;
if (!same_thread_group(leader, task))
goto out_drop_task;
result = proc_task_instantiate(dir, dentry, task, NULL);
out_drop_task:
put_task_struct(task);
out:
put_task_struct(leader);
out_no_task:
return result;
}
/*
* Find the first tid of a thread group to return to user space.
*
* Usually this is just the thread group leader, but if the users
* buffer was too small or there was a seek into the middle of the
* directory we have more work todo.
*
* In the case of a short read we start with find_task_by_pid.
*
* In the case of a seek we start with the leader and walk nr
* threads past it.
*/
static struct task_struct *first_tid(struct task_struct *leader,
int tid, int nr, struct pid_namespace *ns)
{
struct task_struct *pos;
rcu_read_lock();
/* Attempt to start with the pid of a thread */
if (tid && (nr > 0)) {
pos = find_task_by_pid_ns(tid, ns);
if (pos && (pos->group_leader == leader))
goto found;
}
/* If nr exceeds the number of threads there is nothing todo */
pos = NULL;
if (nr && nr >= get_nr_threads(leader))
goto out;
/* If we haven't found our starting place yet start
* with the leader and walk nr threads forward.
*/
for (pos = leader; nr > 0; --nr) {
pos = next_thread(pos);
if (pos == leader) {
pos = NULL;
goto out;
}
}
found:
get_task_struct(pos);
out:
rcu_read_unlock();
return pos;
}
/*
* Find the next thread in the thread list.
* Return NULL if there is an error or no next thread.
*
* The reference to the input task_struct is released.
*/
static struct task_struct *next_tid(struct task_struct *start)
{
struct task_struct *pos = NULL;
rcu_read_lock();
if (pid_alive(start)) {
pos = next_thread(start);
if (thread_group_leader(pos))
pos = NULL;
else
get_task_struct(pos);
}
rcu_read_unlock();
put_task_struct(start);
return pos;
}
static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct task_struct *task, int tid)
{
char name[PROC_NUMBUF];
int len = snprintf(name, sizeof(name), "%d", tid);
return proc_fill_cache(filp, dirent, filldir, name, len,
proc_task_instantiate, task, NULL);
}
/* for the /proc/TGID/task/ directories */
static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
struct task_struct *leader = NULL;
struct task_struct *task;
int retval = -ENOENT;
ino_t ino;
int tid;
unsigned long pos = filp->f_pos; /* avoiding "long long" filp->f_pos */
struct pid_namespace *ns;