fs/proc/net.c

   1 /*
   2  *  linux/fs/proc/net.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  gjh 3/'93 heim@peanuts.informatik.uni-tuebingen.de (Gerald J. Heim)
   7  *            most of this file is stolen from base.c
   8  *            it works, but you shouldn't use it as a guideline
   9  *            for new proc-fs entries. once i'll make it better.
  10  * fvk 3/'93  waltje@uwalt.nl.mugnet.org (Fred N. van Kempen)
  11  *            cleaned up the whole thing, moved "net" specific code to
  12  *            the NET kernel layer (where it belonged in the first place).
  13  * Michael K. Johnson (johnsonm@stolaf.edu) 3/93
  14  *            Added support from my previous inet.c.  Cleaned things up
  15  *            quite a bit, modularized the code.
  16  * fvk 4/'93  waltje@uwalt.nl.mugnet.org (Fred N. van Kempen)
  17  *            Renamed "route_get_info()" to "rt_get_info()" for consistency.
  18  * Alan Cox (gw4pts@gw4pts.ampr.org) 4/94
  19  *            Dusted off the code and added IPX. Fixed the 4K limit.
  20  * Erik Schoenfelder (schoenfr@ibr.cs.tu-bs.de)
  21  *            /proc/net/snmp.
  22  * Alan Cox (gw4pts@gw4pts.ampr.org) 1/95
  23  *            Added AppleTalk slots
  24  *
  25  *  proc net directory handling functions
  26  */
  27 #include <linux/errno.h>
  28 #include <linux/sched.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/stat.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/mm.h>
  33
  34 #include <asm/uaccess.h>
  35
  36 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
  37
  38 static long proc_readnet(struct inode * inode, struct file * file,
  39                         char * buf, unsigned long count)
  40 {
  41         char * page;
  42         int bytes=count;
  43         int copied=0;
  44         char *start;
  45         struct proc_dir_entry * dp;
  46
  47         if (count < 0)
  48                 return -EINVAL;
  49         dp = (struct proc_dir_entry *) inode->u.generic_ip;
  50         if (!(page = (char*) __get_free_page(GFP_KERNEL)))
  51                 return -ENOMEM;
  52
  53         while (bytes>0)
  54         {
  55                 int length, thistime=bytes;
  56                 if (bytes > PROC_BLOCK_SIZE)
  57                         thistime=PROC_BLOCK_SIZE;
  58
  59                 length = dp->get_info(page, &start,
  60                                       file->f_pos,
  61                                       thistime,
  62                                       (file->f_flags & O_ACCMODE) == O_RDWR);
  63
  64                 /*
  65                  *      We have been given a non page aligned block of
  66                  *      the data we asked for + a bit. We have been given
  67                  *      the start pointer and we know the length..
  68                  */
  69
  70                 if (length <= 0)
  71                         break;
  72                 /*
  73                  *      Copy the bytes
  74                  */
  75                 copy_to_user(buf+copied, start, length);
  76                 file->f_pos += length;  /* Move down the file */
  77                 bytes  -= length;
  78                 copied += length;
  79                 if (length<thistime)
  80                         break;  /* End of file */
  81         }
  82         free_page((unsigned long) page);
  83         return copied;
  84 }
  85
  86 static struct file_operations proc_net_operations = {
  87         NULL,                   /* lseek - default */
  88         proc_readnet,           /* read - bad */
  89         NULL,                   /* write - bad */
  90         NULL,                   /* readdir */
  91         NULL,                   /* poll - default */
  92         NULL,                   /* ioctl - default */
  93         NULL,                   /* mmap */
  94         NULL,                   /* no special open code */
  95         NULL,                   /* flush */
  96         NULL,                   /* no special release code */
  97         NULL                    /* can't fsync */
  98 };
  99
 100 /*
 101  * proc directories can do almost nothing..
 102  */
 103 struct inode_operations proc_net_inode_operations = {
 104         &proc_net_operations,   /* default net file-ops */
 105         NULL,                   /* create */
 106         NULL,                   /* lookup */
 107         NULL,                   /* link */
 108         NULL,                   /* unlink */
 109         NULL,                   /* symlink */
 110         NULL,                   /* mkdir */
 111         NULL,                   /* rmdir */
 112         NULL,                   /* mknod */
 113         NULL,                   /* rename */
 114         NULL,                   /* readlink */
 115         NULL,                   /* follow_link */
 116         NULL,                   /* readpage */
 117         NULL,                   /* writepage */
 118         NULL,                   /* bmap */
 119         NULL,                   /* truncate */
 120         NULL                    /* permission */
 121 };