examples/linux-2.6.30_proc_self_exe.patch

   1 This patch makes /proc/self/exe executable even if proc
   2 is not mounted. It is especially useful on NOMMU arches.
   3
   4 diff -urp ../linux-2.6.30.org/fs/exec.c linux-2.6.30/fs/exec.c
   5 --- ../linux-2.6.30.org/fs/exec.c       2009-06-10 05:05:27.000000000 +0200
   6 +++ linux-2.6.30/fs/exec.c      2009-06-25 00:20:13.000000000 +0200
   7 @@ -652,9 +652,25 @@ struct file *open_exec(const char *name)
   8         file = do_filp_open(AT_FDCWD, name,
   9                                 O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
  10                                 MAY_EXEC | MAY_OPEN);
  11 -       if (IS_ERR(file))
  12 -               goto out;
  13 +       if (IS_ERR(file)) {
  14 +               if ((PTR_ERR(file) == -ENOENT || PTR_ERR(file) == -EACCES)
  15 +                && strcmp(name, "/proc/self/exe") == 0
  16 +               ) {
  17 +                       struct file *sv = file;
  18 +                       struct mm_struct *mm;
  19
  20 +                       mm = get_task_mm(current);
  21 +                       if (!mm)
  22 +                               goto out;
  23 +                       file = get_mm_exe_file(mm);
  24 +                       mmput(mm);
  25 +                       if (file)
  26 +                               goto ok;
  27 +                       file = sv;
  28 +               }
  29 +               goto out;
  30 +       }
  31 +ok:
  32         err = -EACCES;
  33         if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
  34                 goto exit;