apps/lib/libmeinos/devfs.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU Lesser General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <sys/types.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <rpc.h>
  23 #include <stdio.h>
  24 #include <sys/shm.h>
  25 #include <llist.h>
  26 #include <errno.h>
  27
  28 #include <devfs.h>
  29
  30 static llist_t devlist;
  31
  32 /**
  33  * Gets list index by DevID
  34  *  @param devid DevID
  35  *  @return List index
  36  */
  37 static int getlidx_id(int devid) {
  38   devfs_dev_t *dev;
  39   int i;
  40   for (i=0;(dev = llist_get(devlist,i));i++) {
  41     if (dev->id==devid) return i;
  42   }
  43   return -1;
  44 }
  45
  46 /**
  47  * Reads from device
  48  *  @param devid DevID
  49  *  @param data Buffer
  50  *  @return How many bytes read (-Errorcode)
  51  */
  52 static int devfs_read(int devid,size_t size,off_t offset) {
  53   devfs_dev_t *dev = llist_get(devlist,getlidx_id(devid));
  54   if (dev->func_read!=NULL) return dev->func_read(dev,dev->shmbuf,size,offset);
  55   else return -ENOSYS;
  56 }
  57
  58 /**
  59  * Writes to device
  60  *  @param devid DevID
  61  *  @param data Buffer
  62  *  @return How many bytes written (-Errorcode)
  63  */
  64 static int devfs_write(int devid,size_t size,off_t offset) {
  65   devfs_dev_t *dev = llist_get(devlist,getlidx_id(devid));
  66   if (dev->func_write!=NULL) return dev->func_write(dev,dev->shmbuf,size,offset);
  67   else return -ENOSYS;
  68 }
  69
  70
  71 #define devfs_func_create(func,synopsis,bufsize) _devfs_func_create(__STRING(func),func,synopsis,bufsize,pid)
  72 static int _devfs_func_create(char *name,void *func,char *synopsis,size_t bufsize,pid_t pid) {
  73   char *rpc;
  74   asprintf(&rpc,"%s_%x",name,pid);
  75   int ret = rpc_func_create(rpc,func,synopsis,bufsize);
  76   free(rpc);
  77   return ret;
  78 }
  79
  80 /**
  81  * Initializes DevFS
  82  */
  83 void devfs_init() {
  84   pid_t pid = getpid();
  85   devlist = llist_create();
  86   devfs_func_create(devfs_read,"iii",sizeof(int)*3);
  87   devfs_func_create(devfs_write,"iii",sizeof(int)*3);
  88 }
  89
  90 /**
  91  * Creates an device
  92  *  @param _name Name of the device
  93  *  @return Device
  94  */
  95 devfs_dev_t *devfs_createdev(const char *name) {
  96   int shmid = shmget(IPC_PRIVATE,DEVFS_BUFSIZE,0);
  97   if (shmid!=-1) {
  98     int id = rpc_call("devfs_createdev",0,name,shmid);
  99     if (id>=0) {
 100       devfs_dev_t *new = malloc(0*sizeof(devfs_dev_t));
 101       new->name = strdup(name);
 102       new->id = id;
 103       new->shmid = shmid;
 104       new->shmbuf = shmat(shmid,NULL,0);
 105       new->func_read = NULL;
 106       new->func_write = NULL;
 107       llist_push(devlist,new);
 108       return new;
 109     }
 110     else shmctl(shmid,IPC_RMID,NULL);
 111   }
 112   return NULL;
 113 }
 114
 115 /**
 116  * Removes an device
 117  *  @param dev Device to remove
 118  */
 119 int devfs_removedev(devfs_dev_t *dev) {
 120   int res = rpc_call("devfs_removedev",0,dev->id);
 121   if (res>=0) {
 122     llist_remove(devlist,getlidx_id(dev->id));
 123     shmdt(dev->shmbuf);
 124     shmctl(dev->shmid,IPC_RMID,NULL);
 125     free(dev->name);
 126     free(dev);
 127   }
 128   return res;
 129 }