cpus_allowed.patch

   1 --- linux-2.4.1/include/linux/proc_fs_i.h       Sat Apr  8 06:38:00 2000
   2 +++ linux-akpm/include/linux/proc_fs_i.h        Fri Feb  2 01:50:40 2001
   3 @@ -1,9 +1,10 @@
   4  struct proc_inode_info {
   5         struct task_struct *task;
   6         int type;
   7 -       union {
   8 +       struct {
   9                 int (*proc_get_link)(struct inode *, struct dentry **, struct vfsmount **);
  10                 int (*proc_read)(struct task_struct *task, char *page);
  11 +               int (*proc_write)(struct task_struct *task, char *page, size_t nbytes);
  12         } op;
  13         struct file *file;
  14  };
  15 --- linux-2.4.1/include/linux/capability.h      Sun Oct 15 01:27:46 2000
  16 +++ linux-akpm/include/linux/capability.h       Fri Feb  2 01:55:00 2001
  17 @@ -231,6 +231,7 @@
  18  /* Allow enabling/disabling tagged queuing on SCSI controllers and sending
  19     arbitrary SCSI commands */
  20  /* Allow setting encryption key on loopback filesystem */
  21 +/* Allow bonding of tasks to CPUs */
  22
  23  #define CAP_SYS_ADMIN        21
  24
  25 --- linux-2.4.1/fs/proc/base.c  Tue Nov 21 20:11:21 2000
  26 +++ linux-akpm/fs/proc/base.c   Fri Feb  2 02:41:51 2001
  27 @@ -39,6 +39,8 @@
  28  int proc_pid_status(struct task_struct*,char*);
  29  int proc_pid_statm(struct task_struct*,char*);
  30  int proc_pid_cpu(struct task_struct*,char*);
  31 +int proc_pid_cpus_allowed_read(struct task_struct *task, char * buffer);
  32 +int proc_pid_cpus_allowed_write(struct task_struct *task, char * buffer, size_t nbytes);
  33
  34  static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
  35  {
  36 @@ -305,8 +307,44 @@
  37         return count;
  38  }
  39
  40 +static ssize_t proc_info_write(struct file * file, const char * buf,
  41 +                         size_t count, loff_t *ppos)
  42 +{
  43 +       struct inode * inode = file->f_dentry->d_inode;
  44 +       unsigned long page;
  45 +       ssize_t ret;
  46 +       struct task_struct *task = inode->u.proc_i.task;
  47 +
  48 +       ret = -EINVAL;
  49 +       if (inode->u.proc_i.op.proc_write == NULL)
  50 +               goto out;
  51 +       if (count > PAGE_SIZE - 1)
  52 +               goto out;
  53 +
  54 +       ret = -ENOMEM;
  55 +       if (!(page = __get_free_page(GFP_KERNEL)))
  56 +               goto out;
  57 +
  58 +       ret = -EFAULT;
  59 +       if (copy_from_user((char *)page, buf, count))
  60 +               goto out_free_page;
  61 +
  62 +       ((char *)page)[count] = '\0';
  63 +       ret = inode->u.proc_i.op.proc_write(task, (char*)page, count);
  64 +       if (ret < 0)
  65 +               goto out_free_page;
  66 +
  67 +       *ppos += ret;
  68 +
  69 +out_free_page:
  70 +       free_page(page);
  71 +out:
  72 +       return ret;
  73 +}
  74 +
  75  static struct file_operations proc_info_file_operations = {
  76         read:           proc_info_read,
  77 +       write:          proc_info_write,
  78  };
  79
  80  #define MAY_PTRACE(p) \
  81 @@ -495,6 +533,7 @@
  82         PROC_PID_STATM,
  83         PROC_PID_MAPS,
  84         PROC_PID_CPU,
  85 +       PROC_PID_CPUS_ALLOWED,
  86         PROC_PID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
  87  };
  88
  89 @@ -507,7 +550,8 @@
  90    E(PROC_PID_STAT,     "stat",         S_IFREG|S_IRUGO),
  91    E(PROC_PID_STATM,    "statm",        S_IFREG|S_IRUGO),
  92  #ifdef CONFIG_SMP
  93 -  E(PROC_PID_CPU,      "cpu",          S_IFREG|S_IRUGO),
  94 +  E(PROC_PID_CPU,              "cpu",          S_IFREG|S_IRUGO),
  95 +  E(PROC_PID_CPUS_ALLOWED,     "cpus_allowed", S_IFREG|S_IRUGO|S_IWUSR),
  96  #endif
  97    E(PROC_PID_MAPS,     "maps",         S_IFREG|S_IRUGO),
  98    E(PROC_PID_MEM,      "mem",          S_IFREG|S_IRUSR|S_IWUSR),
  99 @@ -854,6 +894,11 @@
 100                 case PROC_PID_CPU:
 101                         inode->i_fop = &proc_info_file_operations;
 102                         inode->u.proc_i.op.proc_read = proc_pid_cpu;
 103 +                       break;
 104 +               case PROC_PID_CPUS_ALLOWED:
 105 +                       inode->i_fop = &proc_info_file_operations;
 106 +                       inode->u.proc_i.op.proc_read = proc_pid_cpus_allowed_read;
 107 +                       inode->u.proc_i.op.proc_write = proc_pid_cpus_allowed_write;
 108                         break;
 109  #endif
 110                 case PROC_PID_MEM:
 111 --- linux-2.4.1/fs/proc/array.c Tue Nov 21 20:11:21 2000
 112 +++ linux-akpm/fs/proc/array.c  Fri Feb  2 02:05:39 2001
 113 @@ -50,6 +50,8 @@
 114   * Al Viro & Jeff Garzik :  moved most of the thing into base.c and
 115   *                      :  proc_misc.c. The rest may eventually go into
 116   *                      :  base.c too.
 117 + *
 118 + * Andrew Morton     : cpus_allowed
 119   */
 120
 121  #include <linux/config.h>
 122 @@ -695,5 +697,42 @@
 123                         task->per_cpu_stime[cpu_logical_map(i)]);
 124
 125         return len;
 126 +}
 127 +
 128 +int proc_pid_cpus_allowed_read(struct task_struct *task, char * buffer)
 129 +{
 130 +       int len;
 131 +
 132 +       len = sprintf(buffer, "%08lx\n", task->cpus_allowed);
 133 +       return len;
 134 +}
 135 +
 136 +/*
 137 + * FIXME: cpu_online_map should be used, but not all archs have it.
 138 + */
 139 +
 140 +int proc_pid_cpus_allowed_write(struct task_struct *task, char * buffer, size_t nbytes)
 141 +{
 142 +       unsigned long new_mask;
 143 +       char *endp;
 144 +       int ret;
 145 +       unsigned long flags;
 146 +
 147 +       ret = -EPERM;
 148 +       if (!capable(CAP_SYS_ADMIN))
 149 +               goto out;
 150 +
 151 +       new_mask = simple_strtoul(buffer, &endp, 16);
 152 +       ret = endp - buffer;
 153 +
 154 +       spin_lock_irqsave(&runqueue_lock, flags);       /* token effort to not be racy */
 155 +       if ((((1 << smp_num_cpus) - 1) & new_mask) == 0)
 156 +               ret = -EINVAL;
 157 +       else
 158 +               task->cpus_allowed = new_mask;
 159 +       spin_unlock_irqrestore(&runqueue_lock, flags);
 160 +
 161 +out:
 162 +       return ret;
 163  }
 164  #endif