350 lines
7.4 KiB
C
350 lines
7.4 KiB
C
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/dcache.h>
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#include <linux/path.h>
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#include <linux/fdtable.h>
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#include <linux/namei.h>
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#include <linux/pid.h>
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#include <linux/security.h>
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#include <linux/file.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include "../mount.h"
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#include "internal.h"
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#include "fd.h"
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static int seq_show(struct seq_file *m, void *v)
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{
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struct files_struct *files = NULL;
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int f_flags = 0, ret = -ENOENT;
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struct file *file = NULL;
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struct task_struct *task;
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task = get_proc_task(m->private);
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if (!task)
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return -ENOENT;
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files = get_files_struct(task);
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put_task_struct(task);
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if (files) {
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int fd = proc_fd(m->private);
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spin_lock(&files->file_lock);
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file = fcheck_files(files, fd);
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if (file) {
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struct fdtable *fdt = files_fdtable(files);
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f_flags = file->f_flags;
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if (close_on_exec(fd, fdt))
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f_flags |= O_CLOEXEC;
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get_file(file);
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ret = 0;
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}
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spin_unlock(&files->file_lock);
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put_files_struct(files);
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}
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if (!ret) {
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seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n",
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(long long)file->f_pos, f_flags,
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real_mount(file->f_path.mnt)->mnt_id);
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if (file->f_op->show_fdinfo)
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ret = file->f_op->show_fdinfo(m, file);
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fput(file);
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}
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return ret;
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}
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static int seq_fdinfo_open(struct inode *inode, struct file *file)
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{
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return single_open(file, seq_show, inode);
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}
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static const struct file_operations proc_fdinfo_file_operations = {
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.open = seq_fdinfo_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
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{
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struct files_struct *files;
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struct task_struct *task;
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const struct cred *cred;
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struct inode *inode;
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int fd;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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inode = dentry->d_inode;
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task = get_proc_task(inode);
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fd = proc_fd(inode);
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if (task) {
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files = get_files_struct(task);
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if (files) {
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struct file *file;
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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unsigned f_mode = file->f_mode;
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rcu_read_unlock();
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put_files_struct(files);
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if (task_dumpable(task)) {
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rcu_read_lock();
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cred = __task_cred(task);
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inode->i_uid = cred->euid;
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inode->i_gid = cred->egid;
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rcu_read_unlock();
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} else {
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inode->i_uid = GLOBAL_ROOT_UID;
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inode->i_gid = GLOBAL_ROOT_GID;
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}
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if (S_ISLNK(inode->i_mode)) {
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unsigned i_mode = S_IFLNK;
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if (f_mode & FMODE_READ)
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i_mode |= S_IRUSR | S_IXUSR;
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if (f_mode & FMODE_WRITE)
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i_mode |= S_IWUSR | S_IXUSR;
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inode->i_mode = i_mode;
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}
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security_task_to_inode(task, inode);
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put_task_struct(task);
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return 1;
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}
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rcu_read_unlock();
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put_files_struct(files);
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}
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put_task_struct(task);
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}
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return 0;
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}
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static const struct dentry_operations tid_fd_dentry_operations = {
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.d_revalidate = tid_fd_revalidate,
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.d_delete = pid_delete_dentry,
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};
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static int proc_fd_link(struct dentry *dentry, struct path *path)
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{
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struct files_struct *files = NULL;
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struct task_struct *task;
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int ret = -ENOENT;
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task = get_proc_task(dentry->d_inode);
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if (task) {
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files = get_files_struct(task);
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put_task_struct(task);
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}
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if (files) {
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int fd = proc_fd(dentry->d_inode);
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struct file *fd_file;
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spin_lock(&files->file_lock);
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fd_file = fcheck_files(files, fd);
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if (fd_file) {
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*path = fd_file->f_path;
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path_get(&fd_file->f_path);
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ret = 0;
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}
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spin_unlock(&files->file_lock);
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put_files_struct(files);
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}
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return ret;
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}
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static int
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proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
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struct task_struct *task, const void *ptr)
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{
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unsigned fd = (unsigned long)ptr;
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struct proc_inode *ei;
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struct inode *inode;
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inode = proc_pid_make_inode(dir->i_sb, task);
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if (!inode)
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goto out;
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ei = PROC_I(inode);
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ei->fd = fd;
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inode->i_mode = S_IFLNK;
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inode->i_op = &proc_pid_link_inode_operations;
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inode->i_size = 64;
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ei->op.proc_get_link = proc_fd_link;
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d_set_d_op(dentry, &tid_fd_dentry_operations);
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d_add(dentry, inode);
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/* Close the race of the process dying before we return the dentry */
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if (tid_fd_revalidate(dentry, 0))
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return 0;
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out:
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return -ENOENT;
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}
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static struct dentry *proc_lookupfd_common(struct inode *dir,
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struct dentry *dentry,
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instantiate_t instantiate)
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{
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struct task_struct *task = get_proc_task(dir);
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int result = -ENOENT;
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unsigned fd = name_to_int(&dentry->d_name);
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if (!task)
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goto out_no_task;
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if (fd == ~0U)
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goto out;
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result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
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out:
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put_task_struct(task);
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out_no_task:
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return ERR_PTR(result);
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}
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static int proc_readfd_common(struct file *file, struct dir_context *ctx,
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instantiate_t instantiate)
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{
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struct task_struct *p = get_proc_task(file_inode(file));
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struct files_struct *files;
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unsigned int fd;
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if (!p)
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return -ENOENT;
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if (!dir_emit_dots(file, ctx))
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goto out;
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files = get_files_struct(p);
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if (!files)
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goto out;
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rcu_read_lock();
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for (fd = ctx->pos - 2;
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fd < files_fdtable(files)->max_fds;
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fd++, ctx->pos++) {
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char name[PROC_NUMBUF];
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int len;
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if (!fcheck_files(files, fd))
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continue;
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rcu_read_unlock();
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len = snprintf(name, sizeof(name), "%d", fd);
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if (!proc_fill_cache(file, ctx,
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name, len, instantiate, p,
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(void *)(unsigned long)fd))
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goto out_fd_loop;
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rcu_read_lock();
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}
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rcu_read_unlock();
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out_fd_loop:
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put_files_struct(files);
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out:
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put_task_struct(p);
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return 0;
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}
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static int proc_readfd(struct file *file, struct dir_context *ctx)
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{
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return proc_readfd_common(file, ctx, proc_fd_instantiate);
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}
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const struct file_operations proc_fd_operations = {
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.read = generic_read_dir,
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.iterate = proc_readfd,
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.llseek = default_llseek,
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};
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static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
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unsigned int flags)
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{
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return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
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}
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/*
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* /proc/pid/fd needs a special permission handler so that a process can still
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* access /proc/self/fd after it has executed a setuid().
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*/
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int proc_fd_permission(struct inode *inode, int mask)
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{
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int rv = generic_permission(inode, mask);
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if (rv == 0)
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return 0;
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if (task_tgid(current) == proc_pid(inode))
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rv = 0;
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return rv;
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}
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const struct inode_operations proc_fd_inode_operations = {
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.lookup = proc_lookupfd,
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.permission = proc_fd_permission,
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.setattr = proc_setattr,
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};
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static int
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proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
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struct task_struct *task, const void *ptr)
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{
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unsigned fd = (unsigned long)ptr;
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struct proc_inode *ei;
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struct inode *inode;
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inode = proc_pid_make_inode(dir->i_sb, task);
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if (!inode)
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goto out;
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ei = PROC_I(inode);
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ei->fd = fd;
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inode->i_mode = S_IFREG | S_IRUSR;
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inode->i_fop = &proc_fdinfo_file_operations;
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d_set_d_op(dentry, &tid_fd_dentry_operations);
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d_add(dentry, inode);
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/* Close the race of the process dying before we return the dentry */
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if (tid_fd_revalidate(dentry, 0))
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return 0;
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out:
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return -ENOENT;
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}
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static struct dentry *
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proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
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{
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return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
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}
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static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
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{
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return proc_readfd_common(file, ctx,
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proc_fdinfo_instantiate);
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}
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const struct inode_operations proc_fdinfo_inode_operations = {
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.lookup = proc_lookupfdinfo,
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.setattr = proc_setattr,
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};
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const struct file_operations proc_fdinfo_operations = {
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.read = generic_read_dir,
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.iterate = proc_readfdinfo,
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.llseek = default_llseek,
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};
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