Linux-2.6.12-rc2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / proc / base.c

/*
 *  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.
 */

#include <asm/uaccess.h>

#include <linux/config.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/namei.h>
#include <linux/namespace.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/kallsyms.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/seccomp.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
#include "internal.h"

/*
 * For hysterical raisins we keep the same inumbers as in the old procfs.
 * Feel free to change the macro below - just keep the range distinct from
 * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
 * As soon as we'll get a separate superblock we will be able to forget
 * about magical ranges too.
 */

#define fake_ino(pid,ino) (((pid)<<16)|(ino))

enum pid_directory_inos {
        PROC_TGID_INO = 2,
        PROC_TGID_TASK,
        PROC_TGID_STATUS,
        PROC_TGID_MEM,
#ifdef CONFIG_SECCOMP
        PROC_TGID_SECCOMP,
#endif
        PROC_TGID_CWD,
        PROC_TGID_ROOT,
        PROC_TGID_EXE,
        PROC_TGID_FD,
        PROC_TGID_ENVIRON,
        PROC_TGID_AUXV,
        PROC_TGID_CMDLINE,
        PROC_TGID_STAT,
        PROC_TGID_STATM,
        PROC_TGID_MAPS,
        PROC_TGID_MOUNTS,
        PROC_TGID_WCHAN,
#ifdef CONFIG_SCHEDSTATS
        PROC_TGID_SCHEDSTAT,
#endif
#ifdef CONFIG_CPUSETS
        PROC_TGID_CPUSET,
#endif
#ifdef CONFIG_SECURITY
        PROC_TGID_ATTR,
        PROC_TGID_ATTR_CURRENT,
        PROC_TGID_ATTR_PREV,
        PROC_TGID_ATTR_EXEC,
        PROC_TGID_ATTR_FSCREATE,
#endif
#ifdef CONFIG_AUDITSYSCALL
        PROC_TGID_LOGINUID,
#endif
        PROC_TGID_FD_DIR,
        PROC_TGID_OOM_SCORE,
        PROC_TGID_OOM_ADJUST,
        PROC_TID_INO,
        PROC_TID_STATUS,
        PROC_TID_MEM,
#ifdef CONFIG_SECCOMP
        PROC_TID_SECCOMP,
#endif
        PROC_TID_CWD,
        PROC_TID_ROOT,
        PROC_TID_EXE,
        PROC_TID_FD,
        PROC_TID_ENVIRON,
        PROC_TID_AUXV,
        PROC_TID_CMDLINE,
        PROC_TID_STAT,
        PROC_TID_STATM,
        PROC_TID_MAPS,
        PROC_TID_MOUNTS,
        PROC_TID_WCHAN,
#ifdef CONFIG_SCHEDSTATS
        PROC_TID_SCHEDSTAT,
#endif
#ifdef CONFIG_CPUSETS
        PROC_TID_CPUSET,
#endif
#ifdef CONFIG_SECURITY
        PROC_TID_ATTR,
        PROC_TID_ATTR_CURRENT,
        PROC_TID_ATTR_PREV,
        PROC_TID_ATTR_EXEC,
        PROC_TID_ATTR_FSCREATE,
#endif
#ifdef CONFIG_AUDITSYSCALL
        PROC_TID_LOGINUID,
#endif
        PROC_TID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
        PROC_TID_OOM_SCORE,
        PROC_TID_OOM_ADJUST,
};

struct pid_entry {
        int type;
        int len;
        char *name;
        mode_t mode;
};

#define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}

static struct pid_entry tgid_base_stuff[] = {
        E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
        E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
        E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
        E(PROC_TGID_AUXV,      "auxv",    S_IFREG|S_IRUSR),
        E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
        E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
        E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
        E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
        E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
        E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
#ifdef CONFIG_SECCOMP
        E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
#endif
        E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
        E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
        E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
        E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
#ifdef CONFIG_SECURITY
        E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
#endif
#ifdef CONFIG_KALLSYMS
        E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_SCHEDSTATS
        E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_CPUSETS
        E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
#endif
        E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
        E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
#ifdef CONFIG_AUDITSYSCALL
        E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
        {0,0,NULL,0}
};
static struct pid_entry tid_base_stuff[] = {
        E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
        E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
        E(PROC_TID_AUXV,       "auxv",    S_IFREG|S_IRUSR),
        E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
        E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
        E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
        E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
        E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
        E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
#ifdef CONFIG_SECCOMP
        E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
#endif
        E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
        E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
        E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
        E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
#ifdef CONFIG_SECURITY
        E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
#endif
#ifdef CONFIG_KALLSYMS
        E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_SCHEDSTATS
        E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
#endif
#ifdef CONFIG_CPUSETS
        E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
#endif
        E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
        E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
#ifdef CONFIG_AUDITSYSCALL
        E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
        {0,0,NULL,0}
};

#ifdef CONFIG_SECURITY
static struct pid_entry tgid_attr_stuff[] = {
        E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
        E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
        E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
        E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
        {0,0,NULL,0}
};
static struct pid_entry tid_attr_stuff[] = {
        E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
        E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
        E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
        E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
        {0,0,NULL,0}
};
#endif

#undef E

static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
        struct task_struct *task = proc_task(inode);
        struct files_struct *files;
        struct file *file;
        int fd = proc_type(inode) - PROC_TID_FD_DIR;

        files = get_files_struct(task);
        if (files) {
                spin_lock(&files->file_lock);
                file = fcheck_files(files, fd);
                if (file) {
                        *mnt = mntget(file->f_vfsmnt);
                        *dentry = dget(file->f_dentry);
                        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_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
        struct fs_struct *fs;
        int result = -ENOENT;
        task_lock(proc_task(inode));
        fs = proc_task(inode)->fs;
        if(fs)
                atomic_inc(&fs->count);
        task_unlock(proc_task(inode));
        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 fs_struct *fs;
        int result = -ENOENT;
        task_lock(proc_task(inode));
        fs = proc_task(inode)->fs;
        if(fs)
                atomic_inc(&fs->count);
        task_unlock(proc_task(inode));
        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 may_ptrace_attach(struct task_struct *task)
{
        int retval = 0;

        task_lock(task);

        if (!task->mm)
                goto out;
        if (((current->uid != task->euid) ||
             (current->uid != task->suid) ||
             (current->uid != task->uid) ||
             (current->gid != task->egid) ||
             (current->gid != task->sgid) ||
             (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
                goto out;
        rmb();
        if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
                goto out;
        if (security_ptrace(current, task))
                goto out;

        retval = 1;
out:
        task_unlock(task);
        return retval;
}

static int proc_pid_environ(struct task_struct *task, char * buffer)
{
        int res = 0;
        struct mm_struct *mm = get_task_mm(task);
        if (mm) {
                unsigned int len = mm->env_end - mm->env_start;
                if (len > PAGE_SIZE)
                        len = PAGE_SIZE;
                res = access_process_vm(task, mm->env_start, buffer, len, 0);
                if (!may_ptrace_attach(task))
                        res = -ESRCH;
                mmput(mm);
        }
        return res;
}

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)
{
        char *modname;
        const char *sym_name;
        unsigned long wchan, size, offset;
        char namebuf[KSYM_NAME_LEN+1];

        wchan = get_wchan(task);

        sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
        if (sym_name)
                return sprintf(buffer, "%s", sym_name);
        return sprintf(buffer, "%lu", wchan);
}
#endif /* CONFIG_KALLSYMS */

#ifdef CONFIG_SCHEDSTATS
/*
 * Provides /proc/PID/schedstat
 */
static int proc_pid_schedstat(struct task_struct *task, char *buffer)
{
        return sprintf(buffer, "%lu %lu %lu\n",
                        task->sched_info.cpu_time,
                        task->sched_info.run_delay,
                        task->sched_info.pcnt);
}
#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);
        points = badness(task, uptime.tv_sec);
        return sprintf(buffer, "%lu\n", points);
}

/************************************************************************/
/*                       Here the fs part begins                        */
/************************************************************************/

/* permission checks */

static int proc_check_root(struct inode *inode)
{
        struct dentry *de, *base, *root;
        struct vfsmount *our_vfsmnt, *vfsmnt, *mnt;
        int res = 0;

        if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */
                return -ENOENT;
        read_lock(&current->fs->lock);
        our_vfsmnt = mntget(current->fs->rootmnt);
        base = dget(current->fs->root);
        read_unlock(&current->fs->lock);

        spin_lock(&vfsmount_lock);
        de = root;
        mnt = vfsmnt;

        while (vfsmnt != our_vfsmnt) {
                if (vfsmnt == vfsmnt->mnt_parent)
                        goto out;
                de = vfsmnt->mnt_mountpoint;
                vfsmnt = vfsmnt->mnt_parent;
        }

        if (!is_subdir(de, base))
                goto out;
        spin_unlock(&vfsmount_lock);

exit:
        dput(base);
        mntput(our_vfsmnt);
        dput(root);
        mntput(mnt);
        return res;
out:
        spin_unlock(&vfsmount_lock);
        res = -EACCES;
        goto exit;
}

static int proc_permission(struct inode *inode, int mask, struct nameidata *nd)
{
        if (generic_permission(inode, mask, NULL) != 0)
                return -EACCES;
        return proc_check_root(inode);
}

extern struct seq_operations proc_pid_maps_op;
static int maps_open(struct inode *inode, struct file *file)
{
        struct task_struct *task = proc_task(inode);
        int ret = seq_open(file, &proc_pid_maps_op);
        if (!ret) {
                struct seq_file *m = file->private_data;
                m->private = task;
        }
        return ret;
}

static struct file_operations proc_maps_operations = {
        .open           = maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

extern struct seq_operations mounts_op;
static int mounts_open(struct inode *inode, struct file *file)
{
        struct task_struct *task = proc_task(inode);
        int ret = seq_open(file, &mounts_op);

        if (!ret) {
                struct seq_file *m = file->private_data;
                struct namespace *namespace;
                task_lock(task);
                namespace = task->namespace;
                if (namespace)
                        get_namespace(namespace);
                task_unlock(task);

                if (namespace)
                        m->private = namespace;
                else {
                        seq_release(inode, file);
                        ret = -EINVAL;
                }
        }
        return ret;
}

static int mounts_release(struct inode *inode, struct file *file)
{
        struct seq_file *m = file->private_data;
        struct namespace *namespace = m->private;
        put_namespace(namespace);
        return seq_release(inode, file);
}

static struct file_operations proc_mounts_operations = {
        .open           = mounts_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_dentry->d_inode;
        unsigned long page;
        ssize_t length;
        struct task_struct *task = proc_task(inode);

        if (count > PROC_BLOCK_SIZE)
                count = PROC_BLOCK_SIZE;
        if (!(page = __get_free_page(GFP_KERNEL)))
                return -ENOMEM;

        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);
        return length;
}

static 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 = proc_task(file->f_dentry->d_inode);
        char *page;
        unsigned long src = *ppos;
        int ret = -ESRCH;
        struct mm_struct *mm;

        if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
                goto out;

        ret = -ENOMEM;
        page = (char *)__get_free_page(GFP_USER);
        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) || !may_ptrace_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:
        return ret;
}

#define mem_write NULL

#ifndef mem_write
/* This is a security hazard */
static ssize_t mem_write(struct file * file, const char * buf,
                         size_t count, loff_t *ppos)
{
        int copied = 0;
        char *page;
        struct task_struct *task = proc_task(file->f_dentry->d_inode);
        unsigned long dst = *ppos;

        if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
                return -ESRCH;

        page = (char *)__get_free_page(GFP_USER);
        if (!page)
                return -ENOMEM;

        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);
        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 struct file_operations proc_mem_operations = {
        .llseek         = mem_lseek,
        .read           = mem_read,
        .write          = mem_write,
        .open           = mem_open,
};

static ssize_t oom_adjust_read(struct file *file, char __user *buf,
                                size_t count, loff_t *ppos)
{
        struct task_struct *task = proc_task(file->f_dentry->d_inode);
        char buffer[8];
        size_t len;
        int oom_adjust = task->oomkilladj;
        loff_t __ppos = *ppos;

        len = sprintf(buffer, "%i\n", oom_adjust);
        if (__ppos >= len)
                return 0;
        if (count > len-__ppos)
                count = len-__ppos;
        if (copy_to_user(buf, buffer + __ppos, count))
                return -EFAULT;
        *ppos = __ppos + count;
        return count;
}

static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
                                size_t count, loff_t *ppos)
{
        struct task_struct *task = proc_task(file->f_dentry->d_inode);
        char buffer[8], *end;
        int oom_adjust;

        if (!capable(CAP_SYS_RESOURCE))
                return -EPERM;
        memset(buffer, 0, 8);
        if (count > 6)
                count = 6;
        if (copy_from_user(buffer, buf, count))
                return -EFAULT;
        oom_adjust = simple_strtol(buffer, &end, 0);
        if (oom_adjust < -16 || oom_adjust > 15)
                return -EINVAL;
        if (*end == '\n')
                end++;
        task->oomkilladj = oom_adjust;
        if (end - buffer == 0)
                return -EIO;
        return end - buffer;
}

static struct file_operations proc_oom_adjust_operations = {
        .read           = oom_adjust_read,
        .write          = oom_adjust_write,
};

static struct inode_operations proc_mem_inode_operations = {
        .permission     = proc_permission,
};

#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_dentry->d_inode;
        struct task_struct *task = proc_task(inode);
        ssize_t length;
        char tmpbuf[TMPBUFLEN];

        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
                                audit_get_loginuid(task->audit_context));
        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_dentry->d_inode;
        char *page, *tmp;
        ssize_t length;
        struct task_struct *task = proc_task(inode);
        uid_t loginuid;

        if (!capable(CAP_AUDIT_CONTROL))
                return -EPERM;

        if (current != task)
                return -EPERM;

        if (count > PAGE_SIZE)
                count = PAGE_SIZE;

        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
        page = (char*)__get_free_page(GFP_USER);
        if (!page)
                return -ENOMEM;
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out_free_page;

        loginuid = simple_strtoul(page, &tmp, 10);
        if (tmp == page) {
                length = -EINVAL;
                goto out_free_page;

        }
        length = audit_set_loginuid(task->audit_context, loginuid);
        if (likely(length == 0))
                length = count;

out_free_page:
        free_page((unsigned long) page);
        return length;
}

static struct file_operations proc_loginuid_operations = {
        .read           = proc_loginuid_read,
        .write          = proc_loginuid_write,
};
#endif

#ifdef CONFIG_SECCOMP
static ssize_t seccomp_read(struct file *file, char __user *buf,
                            size_t count, loff_t *ppos)
{
        struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
        char __buf[20];
        loff_t __ppos = *ppos;
        size_t len;

        /* no need to print the trailing zero, so use only len */
        len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
        if (__ppos >= len)
                return 0;
        if (count > len - __ppos)
                count = len - __ppos;
        if (copy_to_user(buf, __buf + __ppos, count))
                return -EFAULT;
        *ppos = __ppos + count;
        return count;
}

static ssize_t seccomp_write(struct file *file, const char __user *buf,
                             size_t count, loff_t *ppos)
{
        struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
        char __buf[20], *end;
        unsigned int seccomp_mode;

        /* can set it only once to be even more secure */
        if (unlikely(tsk->seccomp.mode))
                return -EPERM;

        memset(__buf, 0, sizeof(__buf));
        count = min(count, sizeof(__buf) - 1);
        if (copy_from_user(__buf, buf, count))
                return -EFAULT;
        seccomp_mode = simple_strtoul(__buf, &end, 0);
        if (*end == '\n')
                end++;
        if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
                tsk->seccomp.mode = seccomp_mode;
                set_tsk_thread_flag(tsk, TIF_SECCOMP);
        } else
                return -EINVAL;
        if (unlikely(!(end - __buf)))
                return -EIO;
        return end - __buf;
}

static struct file_operations proc_seccomp_operations = {
        .read           = seccomp_read,
        .write          = seccomp_write,
};
#endif /* CONFIG_SECCOMP */

static int 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);

        if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
                goto out;
        error = proc_check_root(inode);
        if (error)
                goto out;

        error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
        nd->last_type = LAST_BIND;
out:
        return 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_KERNEL), *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;

        lock_kernel();

        if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
                goto out;
        error = proc_check_root(inode);
        if (error)
                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:
        unlock_kernel();
        return error;
}

static struct inode_operations proc_pid_link_inode_operations = {
        .readlink       = proc_pid_readlink,
        .follow_link    = proc_pid_follow_link
};

#define NUMBUF 10

static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
{
        struct inode *inode = filp->f_dentry->d_inode;
        struct task_struct *p = proc_task(inode);
        unsigned int fd, tid, ino;
        int retval;
        char buf[NUMBUF];
        struct files_struct * files;

        retval = -ENOENT;
        if (!pid_alive(p))
                goto out;
        retval = 0;
        tid = p->pid;

        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 = fake_ino(tid, PROC_TID_INO);
                        if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
                                goto out;
                        filp->f_pos++;
                default:
                        files = get_files_struct(p);
                        if (!files)
                                goto out;
                        spin_lock(&files->file_lock);
                        for (fd = filp->f_pos-2;
                             fd < files->max_fds;
                             fd++, filp->f_pos++) {
                                unsigned int i,j;

                                if (!fcheck_files(files, fd))
                                        continue;
                                spin_unlock(&files->file_lock);

                                j = NUMBUF;
                                i = fd;
                                do {
                                        j--;
                                        buf[j] = '0' + (i % 10);
                                        i /= 10;
                                } while (i);

                                ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
                                if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
                                        spin_lock(&files->file_lock);
                                        break;
                                }
                                spin_lock(&files->file_lock);
                        }
                        spin_unlock(&files->file_lock);
                        put_files_struct(files);
        }
out:
        return retval;
}

static int proc_pident_readdir(struct file *filp,
                void *dirent, filldir_t filldir,
                struct pid_entry *ents, unsigned int nents)
{
        int i;
        int pid;
        struct dentry *dentry = filp->f_dentry;
        struct inode *inode = dentry->d_inode;
        struct pid_entry *p;
        ino_t ino;
        int ret;

        ret = -ENOENT;
        if (!pid_alive(proc_task(inode)))
                goto out;

        ret = 0;
        pid = proc_task(inode)->pid;
        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;
                while (p->name) {
                        if (filldir(dirent, p->name, p->len, filp->f_pos,
                                    fake_ino(pid, p->type), p->mode >> 12) < 0)
                                goto out;
                        filp->f_pos++;
                        p++;
                }
        }

        ret = 1;
out:
        return ret;
}

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 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));
}

/* 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 = mm->dumpable;
        task_unlock(task);
        return dumpable;
}


static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
{
        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);
        ei->task = NULL;
        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
        inode->i_ino = fake_ino(task->pid, ino);

        if (!pid_alive(task))
                goto out_unlock;

        /*
         * grab the reference to task.
         */
        get_task_struct(task);
        ei->task = task;
        ei->type = ino;
        inode->i_uid = 0;
        inode->i_gid = 0;
        if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) {
                inode->i_uid = task->euid;
                inode->i_gid = task->egid;
        }
        security_task_to_inode(task, inode);

out:
        return inode;

out_unlock:
        ei->pde = NULL;
        iput(inode);
        return NULL;
}

/* 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.
 */
static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
{
        struct inode *inode = dentry->d_inode;
        struct task_struct *task = proc_task(inode);
        if (pid_alive(task)) {
                if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) {
                        inode->i_uid = task->euid;
                        inode->i_gid = task->egid;
                } else {
                        inode->i_uid = 0;
                        inode->i_gid = 0;
                }
                security_task_to_inode(task, inode);
                return 1;
        }
        d_drop(dentry);
        return 0;
}

static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
{
        struct inode *inode = dentry->d_inode;
        struct task_struct *task = proc_task(inode);
        int fd = proc_type(inode) - PROC_TID_FD_DIR;
        struct files_struct *files;

        files = get_files_struct(task);
        if (files) {
                spin_lock(&files->file_lock);
                if (fcheck_files(files, fd)) {
                        spin_unlock(&files->file_lock);
                        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;
                        }
                        security_task_to_inode(task, inode);
                        return 1;
                }
                spin_unlock(&files->file_lock);
                put_files_struct(files);
        }
        d_drop(dentry);
        return 0;
}

static void pid_base_iput(struct dentry *dentry, struct inode *inode)
{
        struct task_struct *task = proc_task(inode);
        spin_lock(&task->proc_lock);
        if (task->proc_dentry == dentry)
                task->proc_dentry = NULL;
        spin_unlock(&task->proc_lock);
        iput(inode);
}

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 !pid_alive(proc_task(dentry->d_inode));
}

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

static struct dentry_operations pid_dentry_operations =
{
        .d_revalidate   = pid_revalidate,
        .d_delete       = pid_delete_dentry,
};

static struct dentry_operations pid_base_dentry_operations =
{
        .d_revalidate   = pid_revalidate,
        .d_iput         = pid_base_iput,
        .d_delete       = pid_delete_dentry,
};

/* Lookups */

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;
}

/* SMP-safe */
static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
{
        struct task_struct *task = proc_task(dir);
        unsigned fd = name_to_int(dentry);
        struct file * file;
        struct files_struct * files;
        struct inode *inode;
        struct proc_inode *ei;

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

        inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
        if (!inode)
                goto out;
        ei = PROC_I(inode);
        files = get_files_struct(task);
        if (!files)
                goto out_unlock;
        inode->i_mode = S_IFLNK;
        spin_lock(&files->file_lock);
        file = fcheck_files(files, fd);
        if (!file)
                goto out_unlock2;
        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);
        return NULL;

out_unlock2:
        spin_unlock(&files->file_lock);
        put_files_struct(files);
out_unlock:
        iput(inode);
out:
        return ERR_PTR(-ENOENT);
}

static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);

static struct file_operations proc_fd_operations = {
        .read           = generic_read_dir,
        .readdir        = proc_readfd,
};

static struct file_operations proc_task_operations = {
        .read           = generic_read_dir,
        .readdir        = proc_task_readdir,
};

/*
 * proc directories can do almost nothing..
 */
static struct inode_operations proc_fd_inode_operations = {
        .lookup         = proc_lookupfd,
        .permission     = proc_permission,
};

static struct inode_operations proc_task_inode_operations = {
        .lookup         = proc_task_lookup,
        .permission     = proc_permission,
};

#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_dentry->d_inode;
        unsigned long page;
        ssize_t length;
        struct task_struct *task = proc_task(inode);

        if (count > PAGE_SIZE)
                count = PAGE_SIZE;
        if (!(page = __get_free_page(GFP_KERNEL)))
                return -ENOMEM;

        length = security_getprocattr(task, 
                                      (char*)file->f_dentry->d_name.name, 
                                      (void*)page, count);
        if (length >= 0)
                length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
        free_page(page);
        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_dentry->d_inode;
        char *page; 
        ssize_t length; 
        struct task_struct *task = proc_task(inode); 

        if (count > PAGE_SIZE) 
                count = PAGE_SIZE; 
        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
        page = (char*)__get_free_page(GFP_USER); 
        if (!page) 
                return -ENOMEM;
        length = -EFAULT; 
        if (copy_from_user(page, buf, count)) 
                goto out;

        length = security_setprocattr(task, 
                                      (char*)file->f_dentry->d_name.name, 
                                      (void*)page, count);
out:
        free_page((unsigned long) page);
        return length;
} 

static struct file_operations proc_pid_attr_operations = {
        .read           = proc_pid_attr_read,
        .write          = proc_pid_attr_write,
};

static struct file_operations proc_tid_attr_operations;
static struct inode_operations proc_tid_attr_inode_operations;
static struct file_operations proc_tgid_attr_operations;
static struct inode_operations proc_tgid_attr_inode_operations;
#endif

/* SMP-safe */
static struct dentry *proc_pident_lookup(struct inode *dir, 
                                         struct dentry *dentry,
                                         struct pid_entry *ents)
{
        struct inode *inode;
        int error;
        struct task_struct *task = proc_task(dir);
        struct pid_entry *p;
        struct proc_inode *ei;

        error = -ENOENT;
        inode = NULL;

        if (!pid_alive(task))
                goto out;

        for (p = ents; p->name; p++) {
                if (p->len != dentry->d_name.len)
                        continue;
                if (!memcmp(dentry->d_name.name, p->name, p->len))
                        break;
        }
        if (!p->name)
                goto out;

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

        ei = PROC_I(inode);
        inode->i_mode = p->mode;
        /*
         * Yes, it does not scale. And it should not. Don't add
         * new entries into /proc/<tgid>/ without very good reasons.
         */
        switch(p->type) {
                case PROC_TGID_TASK:
                        inode->i_nlink = 3;
                        inode->i_op = &proc_task_inode_operations;
                        inode->i_fop = &proc_task_operations;
                        break;
                case PROC_TID_FD:
                case PROC_TGID_FD:
                        inode->i_nlink = 2;
                        inode->i_op = &proc_fd_inode_operations;
                        inode->i_fop = &proc_fd_operations;
                        break;
                case PROC_TID_EXE:
                case PROC_TGID_EXE:
                        inode->i_op = &proc_pid_link_inode_operations;
                        ei->op.proc_get_link = proc_exe_link;
                        break;
                case PROC_TID_CWD:
                case PROC_TGID_CWD:
                        inode->i_op = &proc_pid_link_inode_operations;
                        ei->op.proc_get_link = proc_cwd_link;
                        break;
                case PROC_TID_ROOT:
                case PROC_TGID_ROOT:
                        inode->i_op = &proc_pid_link_inode_operations;
                        ei->op.proc_get_link = proc_root_link;
                        break;
                case PROC_TID_ENVIRON:
                case PROC_TGID_ENVIRON:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_environ;
                        break;
                case PROC_TID_AUXV:
                case PROC_TGID_AUXV:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_auxv;
                        break;
                case PROC_TID_STATUS:
                case PROC_TGID_STATUS:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_status;
                        break;
                case PROC_TID_STAT:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_tid_stat;
                        break;
                case PROC_TGID_STAT:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_tgid_stat;
                        break;
                case PROC_TID_CMDLINE:
                case PROC_TGID_CMDLINE:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_cmdline;
                        break;
                case PROC_TID_STATM:
                case PROC_TGID_STATM:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_statm;
                        break;
                case PROC_TID_MAPS:
                case PROC_TGID_MAPS:
                        inode->i_fop = &proc_maps_operations;
                        break;
                case PROC_TID_MEM:
                case PROC_TGID_MEM:
                        inode->i_op = &proc_mem_inode_operations;
                        inode->i_fop = &proc_mem_operations;
                        break;
#ifdef CONFIG_SECCOMP
                case PROC_TID_SECCOMP:
                case PROC_TGID_SECCOMP:
                        inode->i_fop = &proc_seccomp_operations;
                        break;
#endif /* CONFIG_SECCOMP */
                case PROC_TID_MOUNTS:
                case PROC_TGID_MOUNTS:
                        inode->i_fop = &proc_mounts_operations;
                        break;
#ifdef CONFIG_SECURITY
                case PROC_TID_ATTR:
                        inode->i_nlink = 2;
                        inode->i_op = &proc_tid_attr_inode_operations;
                        inode->i_fop = &proc_tid_attr_operations;
                        break;
                case PROC_TGID_ATTR:
                        inode->i_nlink = 2;
                        inode->i_op = &proc_tgid_attr_inode_operations;
                        inode->i_fop = &proc_tgid_attr_operations;
                        break;
                case PROC_TID_ATTR_CURRENT:
                case PROC_TGID_ATTR_CURRENT:
                case PROC_TID_ATTR_PREV:
                case PROC_TGID_ATTR_PREV:
                case PROC_TID_ATTR_EXEC:
                case PROC_TGID_ATTR_EXEC:
                case PROC_TID_ATTR_FSCREATE:
                case PROC_TGID_ATTR_FSCREATE:
                        inode->i_fop = &proc_pid_attr_operations;
                        break;
#endif
#ifdef CONFIG_KALLSYMS
                case PROC_TID_WCHAN:
                case PROC_TGID_WCHAN:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_wchan;
                        break;
#endif
#ifdef CONFIG_SCHEDSTATS
                case PROC_TID_SCHEDSTAT:
                case PROC_TGID_SCHEDSTAT:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_pid_schedstat;
                        break;
#endif
#ifdef CONFIG_CPUSETS
                case PROC_TID_CPUSET:
                case PROC_TGID_CPUSET:
                        inode->i_fop = &proc_cpuset_operations;
                        break;
#endif
                case PROC_TID_OOM_SCORE:
                case PROC_TGID_OOM_SCORE:
                        inode->i_fop = &proc_info_file_operations;
                        ei->op.proc_read = proc_oom_score;
                        break;
                case PROC_TID_OOM_ADJUST:
                case PROC_TGID_OOM_ADJUST:
                        inode->i_fop = &proc_oom_adjust_operations;
                        break;
#ifdef CONFIG_AUDITSYSCALL
                case PROC_TID_LOGINUID:
                case PROC_TGID_LOGINUID:
                        inode->i_fop = &proc_loginuid_operations;
                        break;
#endif
                default:
                        printk("procfs: impossible type (%d)",p->type);
                        iput(inode);
                        return ERR_PTR(-EINVAL);
        }
        dentry->d_op = &pid_dentry_operations;
        d_add(dentry, inode);
        return NULL;

out:
        return ERR_PTR(error);
}

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);
}

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);
}

static struct file_operations proc_tgid_base_operations = {
        .read           = generic_read_dir,
        .readdir        = proc_tgid_base_readdir,
};

static struct file_operations proc_tid_base_operations = {
        .read           = generic_read_dir,
        .readdir        = proc_tid_base_readdir,
};

static struct inode_operations proc_tgid_base_inode_operations = {
        .lookup         = proc_tgid_base_lookup,
};

static struct inode_operations proc_tid_base_inode_operations = {
        .lookup         = proc_tid_base_lookup,
};

#ifdef CONFIG_SECURITY
static int proc_tgid_attr_readdir(struct file * filp,
                             void * dirent, filldir_t filldir)
{
        return proc_pident_readdir(filp,dirent,filldir,
                                   tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
}

static int proc_tid_attr_readdir(struct file * filp,
                             void * dirent, filldir_t filldir)
{
        return proc_pident_readdir(filp,dirent,filldir,
                                   tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
}

static struct file_operations proc_tgid_attr_operations = {
        .read           = generic_read_dir,
        .readdir        = proc_tgid_attr_readdir,
};

static struct file_operations proc_tid_attr_operations = {
        .read           = generic_read_dir,
        .readdir        = proc_tid_attr_readdir,
};

static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
                                struct dentry *dentry, struct nameidata *nd)
{
        return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
}

static struct dentry *proc_tid_attr_lookup(struct inode *dir,
                                struct dentry *dentry, struct nameidata *nd)
{
        return proc_pident_lookup(dir, dentry, tid_attr_stuff);
}

static struct inode_operations proc_tgid_attr_inode_operations = {
        .lookup         = proc_tgid_attr_lookup,
};

static struct inode_operations proc_tid_attr_inode_operations = {
        .lookup         = proc_tid_attr_lookup,
};
#endif

/*
 * /proc/self:
 */
static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
                              int buflen)
{
        char tmp[30];
        sprintf(tmp, "%d", current->tgid);
        return vfs_readlink(dentry,buffer,buflen,tmp);
}

static int proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
{
        char tmp[30];
        sprintf(tmp, "%d", current->tgid);
        return vfs_follow_link(nd,tmp);
}       

static struct inode_operations proc_self_inode_operations = {
        .readlink       = proc_self_readlink,
        .follow_link    = proc_self_follow_link,
};

/**
 * proc_pid_unhash -  Unhash /proc/<pid> entry from the dcache.
 * @p: task that should be flushed.
 *
 * Drops the /proc/<pid> dcache entry from the hash chains.
 *
 * Dropping /proc/<pid> entries and detach_pid must be synchroneous,
 * otherwise e.g. /proc/<pid>/exe might point to the wrong executable,
 * if the pid value is immediately reused. This is enforced by
 * - caller must acquire spin_lock(p->proc_lock)
 * - must be called before detach_pid()
 * - proc_pid_lookup acquires proc_lock, and checks that
 *   the target is not dead by looking at the attach count
 *   of PIDTYPE_PID.
 */

struct dentry *proc_pid_unhash(struct task_struct *p)
{
        struct dentry *proc_dentry;

        proc_dentry = p->proc_dentry;
        if (proc_dentry != NULL) {

                spin_lock(&dcache_lock);
                spin_lock(&proc_dentry->d_lock);
                if (!d_unhashed(proc_dentry)) {
                        dget_locked(proc_dentry);
                        __d_drop(proc_dentry);
                        spin_unlock(&proc_dentry->d_lock);
                } else {
                        spin_unlock(&proc_dentry->d_lock);
                        proc_dentry = NULL;
                }
                spin_unlock(&dcache_lock);
        }
        return proc_dentry;
}

/**
 * proc_pid_flush - recover memory used by stale /proc/<pid>/x entries
 * @proc_entry: directoy to prune.
 *
 * Shrink the /proc directory that was used by the just killed thread.
 */
        
void proc_pid_flush(struct dentry *proc_dentry)
{
        might_sleep();
        if(proc_dentry != NULL) {
                shrink_dcache_parent(proc_dentry);
                dput(proc_dentry);
        }
}

/* SMP-safe */
struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
        struct task_struct *task;
        struct inode *inode;
        struct proc_inode *ei;
        unsigned tgid;
        int died;

        if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
                inode = new_inode(dir->i_sb);
                if (!inode)
                        return ERR_PTR(-ENOMEM);
                ei = PROC_I(inode);
                inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
                inode->i_ino = fake_ino(0, PROC_TGID_INO);
                ei->pde = NULL;
                inode->i_mode = S_IFLNK|S_IRWXUGO;
                inode->i_uid = inode->i_gid = 0;
                inode->i_size = 64;
                inode->i_op = &proc_self_inode_operations;
                d_add(dentry, inode);
                return NULL;
        }
        tgid = name_to_int(dentry);
        if (tgid == ~0U)
                goto out;

        read_lock(&tasklist_lock);
        task = find_task_by_pid(tgid);
        if (task)
                get_task_struct(task);
        read_unlock(&tasklist_lock);
        if (!task)
                goto out;

        inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);


        if (!inode) {
                put_task_struct(task);
                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_nlink = 3;
        inode->i_flags|=S_IMMUTABLE;

        dentry->d_op = &pid_base_dentry_operations;

        died = 0;
        d_add(dentry, inode);
        spin_lock(&task->proc_lock);
        task->proc_dentry = dentry;
        if (!pid_alive(task)) {
                dentry = proc_pid_unhash(task);
                died = 1;
        }
        spin_unlock(&task->proc_lock);

        put_task_struct(task);
        if (died) {
                proc_pid_flush(dentry);
                goto out;
        }
        return NULL;
out:
        return ERR_PTR(-ENOENT);
}

/* SMP-safe */
static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
        struct task_struct *task;
        struct task_struct *leader = proc_task(dir);
        struct inode *inode;
        unsigned tid;

        tid = name_to_int(dentry);
        if (tid == ~0U)
                goto out;

        read_lock(&tasklist_lock);
        task = find_task_by_pid(tid);
        if (task)
                get_task_struct(task);
        read_unlock(&tasklist_lock);
        if (!task)
                goto out;
        if (leader->tgid != task->tgid)
                goto out_drop_task;

        inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);


        if (!inode)
                goto out_drop_task;
        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_nlink = 3;
        inode->i_flags|=S_IMMUTABLE;

        dentry->d_op = &pid_base_dentry_operations;

        d_add(dentry, inode);

        put_task_struct(task);
        return NULL;
out_drop_task:
        put_task_struct(task);
out:
        return ERR_PTR(-ENOENT);
}

#define PROC_NUMBUF 10
#define PROC_MAXPIDS 20

/*
 * Get a few tgid's to return for filldir - we need to hold the
 * tasklist lock while doing this, and we must release it before
 * we actually do the filldir itself, so we use a temp buffer..
 */
static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
{
        struct task_struct *p;
        int nr_tgids = 0;

        index--;
        read_lock(&tasklist_lock);
        p = NULL;
        if (version) {
                p = find_task_by_pid(version);
                if (p && !thread_group_leader(p))
                        p = NULL;
        }

        if (p)
                index = 0;
        else
                p = next_task(&init_task);

        for ( ; p != &init_task; p = next_task(p)) {
                int tgid = p->pid;
                if (!pid_alive(p))
                        continue;
                if (--index >= 0)
                        continue;
                tgids[nr_tgids] = tgid;
                nr_tgids++;
                if (nr_tgids >= PROC_MAXPIDS)
                        break;
        }
        read_unlock(&tasklist_lock);
        return nr_tgids;
}

/*
 * Get a few tid's to return for filldir - we need to hold the
 * tasklist lock while doing this, and we must release it before
 * we actually do the filldir itself, so we use a temp buffer..
 */
static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
{
        struct task_struct *leader_task = proc_task(dir);
        struct task_struct *task = leader_task;
        int nr_tids = 0;

        index -= 2;
        read_lock(&tasklist_lock);
        /*
         * The starting point task (leader_task) might be an already
         * unlinked task, which cannot be used to access the task-list
         * via next_thread().
         */
        if (pid_alive(task)) do {
                int tid = task->pid;

                if (--index >= 0)
                        continue;
                tids[nr_tids] = tid;
                nr_tids++;
                if (nr_tids >= PROC_MAXPIDS)
                        break;
        } while ((task = next_thread(task)) != leader_task);
        read_unlock(&tasklist_lock);
        return nr_tids;
}

/* 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 tgid_array[PROC_MAXPIDS];
        char buf[PROC_NUMBUF];
        unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
        unsigned int nr_tgids, i;
        int next_tgid;

        if (!nr) {
                ino_t ino = fake_ino(0,PROC_TGID_INO);
                if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
                        return 0;
                filp->f_pos++;
                nr++;
        }

        /* f_version caches the tgid value that the last readdir call couldn't
         * return. lseek aka telldir automagically resets f_version to 0.
         */
        next_tgid = filp->f_version;
        filp->f_version = 0;
        for (;;) {
                nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
                if (!nr_tgids) {
                        /* no more entries ! */
                        break;
                }
                next_tgid = 0;

                /* do not use the last found pid, reserve it for next_tgid */
                if (nr_tgids == PROC_MAXPIDS) {
                        nr_tgids--;
                        next_tgid = tgid_array[nr_tgids];
                }

                for (i=0;i<nr_tgids;i++) {
                        int tgid = tgid_array[i];
                        ino_t ino = fake_ino(tgid,PROC_TGID_INO);
                        unsigned long j = PROC_NUMBUF;

                        do
                                buf[--j] = '0' + (tgid % 10);
                        while ((tgid /= 10) != 0);

                        if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
                                /* returning this tgid failed, save it as the first
                                 * pid for the next readir call */
                                filp->f_version = tgid_array[i];
                                goto out;
                        }
                        filp->f_pos++;
                        nr++;
                }
        }
out:
        return 0;
}

/* for the /proc/TGID/task/ directories */
static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
        unsigned int tid_array[PROC_MAXPIDS];
        char buf[PROC_NUMBUF];
        unsigned int nr_tids, i;
        struct dentry *dentry = filp->f_dentry;
        struct inode *inode = dentry->d_inode;
        int retval = -ENOENT;
        ino_t ino;
        unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */

        if (!pid_alive(proc_task(inode)))
                goto out;
        retval = 0;

        switch (pos) {
        case 0:
                ino = inode->i_ino;
                if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
                        goto out;
                pos++;
                /* fall through */
        case 1:
                ino = parent_ino(dentry);
                if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
                        goto out;
                pos++;
                /* fall through */
        }

        nr_tids = get_tid_list(pos, tid_array, inode);

        for (i = 0; i < nr_tids; i++) {
                unsigned long j = PROC_NUMBUF;
                int tid = tid_array[i];

                ino = fake_ino(tid,PROC_TID_INO);

                do
                        buf[--j] = '0' + (tid % 10);
                while ((tid /= 10) != 0);

                if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
                        break;
                pos++;
        }
out:
        filp->f_pos = pos;
        return retval;
}