apps/devfs/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 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 General Public License for more details.
  14
  15     You should have received a copy of the GNU 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 <sys/shm.h>
  21 #include <rpc.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <llist.h>
  25 #include <fuse.h>
  26
  27 struct devlist_item {
  28   int id;
  29   char *name;
  30   pid_t owner;
  31   enum { DT_CHAR,DT_BLOCK } type;
  32   void *shmbuf;
  33 };
  34
  35 llist_t devlist;
  36 int nextdevid;
  37
  38 #define getnew_devid() (nextdevid++)
  39
  40 /**
  41  * Gets ListID by DevID
  42  *  @param devid DevID
  43  *  @return ListID
  44  */
  45 int getlid_devid(int devid) {
  46   struct devlist_item *dev;
  47   int i;
  48   for (i=0;(dev = llist_get(devlist,i));i++) {
  49     if (dev->id==devid) return i;
  50   }
  51   return -1;
  52 }
  53
  54 /**
  55  * Gets device by name
  56  *  @param name Device name
  57  *  @return Device
  58  */
  59 struct devlist_item *getdev_name(char *name) {
  60   struct devlist_item *dev;
  61   int i;
  62
  63   for (i=0;(dev = llist_get(devlist,i));i++) {
  64     if (strcmp(dev->name,name)==0) return dev;
  65   }
  66   return NULL;
  67 }
  68
  69 /**
  70  * Opens a file
  71  *  @param path Path to file
  72  *  @param fi File Info
  73  *  @return Filehandle
  74  */
  75 int devfs_open(const char *path,struct fuse_file_info *fi) {
  76   struct devlist_item *dev = getdev_name((char*)path+1);
  77   if (dev!=NULL) return 0;
  78   else return -ENOENT;
  79 }
  80
  81 /**
  82  * Closes a file
  83  *  @param path Path to file
  84  *  @param fi File Info
  85  *  @return Success?
  86  */
  87 int devfs_close(const char *path,struct fuse_file_info *fi) {
  88   return 0;
  89 }
  90
  91 /**
  92  * Reads from file
  93  *  @param path Path to file
  94  *  @param buf Buffer to store read data in
  95  *  @param count How many bytes to read
  96  *  @param offset Offset to start at
  97  *  @param fi File info
  98  *  @return How many bytes read (-Errorcode)
  99  */
 100 int devfs_read(const char *path,char *buf,size_t count,off_t offset,struct fuse_file_info *fi) {
 101   struct devlist_item *dev = getdev_name((char*)path+1);
 102   char *func;
 103   if (dev!=NULL) {
 104     asprintf(&func,"devfs_read_%x",dev->owner);
 105     int ret = rpc_call(func,0,dev->id,count,offset);
 106     memcpy(buf,dev->shmbuf,count);
 107     free(func);
 108     return ret;
 109   }
 110   else return -ENOENT;
 111 }
 112
 113 /**
 114  * Writes to file
 115  *  @param path Path to file
 116  *  @param buf Buffer to get data from
 117  *  @param count How many bytes to write
 118  *  @param offset Offset to start at
 119  *  @param fi File info
 120  *  @return How many bytes written (-Errorcode)
 121  */
 122 int devfs_write(const char *path,const char *buf,size_t count,off_t offset,struct fuse_file_info *fi) {
 123   struct devlist_item *dev = getdev_name((char*)path+1);
 124   char *func;
 125   if (dev!=NULL) {
 126     asprintf(&func,"devfs_write_%x",dev->owner);
 127     memcpy(dev->shmbuf,buf,count);
 128     int ret = rpc_call(func,0,dev->id,count,offset);
 129     free(func);
 130     return ret;
 131   }
 132   else return -ENOENT;
 133 }
 134
 135 /**
 136  * Reads from dir
 137  *  @param path Path to dir
 138  *  @param buf Buffer for dir entries
 139  *  @param filler Filler function
 140  *  @param off Dir offset
 141  *  @param fi File info
 142  *  @return 0=success (-Errorcode)
 143  */
 144 int devfs_readdir(const char *path,void *buf,fuse_fill_dir_t filler,off_t off,struct fuse_file_info *fi) {
 145   if (strcmp(path,"/")==0) {
 146     size_t i;
 147     struct devlist_item *dev;
 148     filler(buf,".",NULL,0);
 149     filler(buf,"..",NULL,0);
 150     for (i=0;(dev = llist_get(devlist,i));i++) filler(buf,dev->name,NULL,0);
 151     return 0;
 152   }
 153   else return -ENOENT;
 154 }
 155
 156 /**
 157  * Gets informations about files
 158  *  @param path Path to file
 159  *  @param stbuf Buffer to store informations in
 160  *  @return 0=success (-Errorcode)
 161  */
 162 int devfs_getattr(const char *path,struct stat *stbuf) {
 163   struct devlist_item *dev;
 164   memset(stbuf,0,sizeof(struct stat));
 165   if (strcmp(path,"/") == 0) {
 166     stbuf->st_mode = S_IFDIR|0755;
 167     stbuf->st_nlink = 2;
 168   }
 169   else if ((dev = getdev_name((char*)path+1))!=NULL) {
 170     stbuf->st_mode = (dev->type==DT_BLOCK?S_IFBLK:S_IFCHR)|0744;
 171     stbuf->st_nlink = 1;
 172     stbuf->st_size = 0;
 173   }
 174   else return -ENOENT;
 175   return 0;
 176 }
 177
 178 /**
 179  * Creates a new device
 180  *  @param name Device name
 181  *  @return DevID
 182  */
 183 int devfs_createdev(char *name,int shmid) {
 184   int devid = getnew_devid();
 185   if (devid>=0 && getdev_name(name)==NULL) {
 186     struct devlist_item *new = malloc(sizeof(struct devlist_item));
 187     new->id = devid;
 188     new->name = strdup(name);
 189     new->owner = rpc_curpid;
 190     new->shmbuf = shmat(shmid,NULL,0);
 191     llist_push(devlist,new);
 192     return devid;
 193   }
 194   else {
 195     fprintf(stderr,"devfs: Could not create device: %s\n",name);
 196     return -1;
 197   }
 198 }
 199
 200 /**
 201  * Removes a device
 202  *  @param id DevID
 203  *  @return 0=success; -1=failure
 204  */
 205 int devfs_removedev(int id) {
 206   struct devlist_item *dev = llist_get(devlist,getlid_devid(id));
 207   if (dev!=NULL && dev->owner==rpc_curpid) {
 208     llist_remove(devlist,getlid_devid(id));
 209     shmdt(dev->shmbuf);
 210     free(dev->name);
 211     free(dev);
 212     return 0;
 213   }
 214   return -1;
 215 }
 216
 217 /**
 218  * Initializes DevFS
 219  *  @param argc Number of arguments
 220  *  @param argv Values of arguments
 221  *  @return Return value
 222  */
 223 int main(int argc,char *argv[]) {
 224   devlist = llist_create();
 225   nextdevid = 1;
 226
 227   rpc_func(devfs_createdev,"$i",NAME_MAX+sizeof(int));
 228   rpc_func(devfs_removedev,"i",sizeof(int));
 229
 230   struct fuse_operations devfs_oper = {
 231     .open = devfs_open,
 232     .release = devfs_close,
 233     .read = devfs_read,
 234     .write = devfs_write,
 235     .readdir = devfs_readdir,
 236     .getattr = devfs_getattr
 237   };
 238
 239   // fake argc/argv
 240   int fake_argc = 2;
 241   char *fake_argv[2] = { "devfs","/dev" };
 242   fuse_main(fake_argc,fake_argv,&devfs_oper,NULL);
 243
 244   return 0;
 245 }