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   size_t bufsz;
  34 };
  35
  36 static llist_t devlist;
  37 static int nextdevid;
  38
  39 #define getnew_devid() (nextdevid++)
  40
  41 /**
  42  * Gets ListID by DevID
  43  *  @param devid DevID
  44  *  @return ListID
  45  */
  46 static int getlid_devid(int devid) {
  47   struct devlist_item *dev;
  48   int i;
  49   for (i=0;(dev = llist_get(devlist,i));i++) {
  50     if (dev->id==devid) return i;
  51   }
  52   return -1;
  53 }
  54
  55 /**
  56  * Gets device by name
  57  *  @param name Device name
  58  *  @return Device
  59  */
  60 static struct devlist_item *getdev_name(char *name) {
  61   struct devlist_item *dev;
  62   int i;
  63
  64   for (i=0;(dev = llist_get(devlist,i));i++) {
  65     if (strcmp(dev->name,name)==0) return dev;
  66   }
  67   return NULL;
  68 }
  69
  70 /**
  71  * Opens a file
  72  *  @param path Path to file
  73  *  @param fi File Info
  74  *  @return Filehandle
  75  */
  76 static int devfs_open(const char *path,struct fuse_file_info *fi) {
  77   struct devlist_item *dev = getdev_name((char*)path+1);
  78   if (dev!=NULL) return 0;
  79   else return -ENOENT;
  80 }
  81
  82 /**
  83  * Closes a file
  84  *  @param path Path to file
  85  *  @param fi File Info
  86  *  @return Success?
  87  */
  88 static int devfs_close(const char *path,struct fuse_file_info *fi) {
  89   return 0;
  90 }
  91
  92 /**
  93  * Reads from file
  94  *  @param path Path to file
  95  *  @param buf Buffer to store read data in
  96  *  @param count How many bytes to read
  97  *  @param offset Offset to start at
  98  *  @param fi File info
  99  *  @return How many bytes read (-Errorcode)
 100  */
 101 static int devfs_read(const char *path,char *buf,size_t count,off_t offset,struct fuse_file_info *fi) {
 102   struct devlist_item *dev = getdev_name((char*)path+1);
 103   if (dev!=NULL) {
 104     if (count>dev->bufsz) count = dev->bufsz;
 105 //dbgmsg("devfs:\tdevfs_read(%s,0x%x,0x%x,0x%x)\n",path,buf,count,offset);
 106     int ret = rpc_call("devfs_read",RPC_FLAG_SENDTO,dev->owner,dev->id,count,offset);
 107 //dbgmsg("devfs:\tret = 0x%x\n",ret);
 108     memcpy(buf,dev->shmbuf,ret);
 109     return ret;
 110   }
 111   else return -ENOENT;
 112 }
 113
 114 /**
 115  * Writes to file
 116  *  @param path Path to file
 117  *  @param buf Buffer to get data from
 118  *  @param count How many bytes to write
 119  *  @param offset Offset to start at
 120  *  @param fi File info
 121  *  @return How many bytes written (-Errorcode)
 122  */
 123 static int devfs_write(const char *path,const char *buf,size_t count,off_t offset,struct fuse_file_info *fi) {
 124   struct devlist_item *dev = getdev_name((char*)path+1);
 125   if (dev!=NULL) {
 126     if (count>dev->bufsz) count = dev->bufsz;
 127     memcpy(dev->shmbuf,buf,count);
 128     return rpc_call("devfs_write",RPC_FLAG_SENDTO,dev->owner,dev->id,count,offset);
 129   }
 130   else return -ENOENT;
 131 }
 132
 133 /**
 134  * Reads from dir
 135  *  @param path Path to dir
 136  *  @param buf Buffer for dir entries
 137  *  @param filler Filler function
 138  *  @param off Dir offset
 139  *  @param fi File info
 140  *  @return 0=success (-Errorcode)
 141  */
 142 static int devfs_readdir(const char *path,void *buf,fuse_fill_dir_t filler,off_t off,struct fuse_file_info *fi) {
 143   if (strcmp(path,"/")==0) {
 144     size_t i;
 145     struct devlist_item *dev;
 146     filler(buf,".",NULL,0);
 147     filler(buf,"..",NULL,0);
 148     for (i=0;(dev = llist_get(devlist,i));i++) filler(buf,dev->name,NULL,0);
 149     return 0;
 150   }
 151   else return -ENOENT;
 152 }
 153
 154 /**
 155  * Gets informations about files
 156  *  @param path Path to file
 157  *  @param stbuf Buffer to store informations in
 158  *  @return 0=success (-Errorcode)
 159  */
 160 static int devfs_getattr(const char *path,struct stat *stbuf) {
 161   struct devlist_item *dev;
 162   memset(stbuf,0,sizeof(struct stat));
 163   if (strcmp(path,"/") == 0) {
 164     stbuf->st_mode = S_IFDIR|0755;
 165     stbuf->st_nlink = 2;
 166   }
 167   else if ((dev = getdev_name((char*)path+1))!=NULL) {
 168     stbuf->st_mode = (dev->type==DT_BLOCK?S_IFBLK:S_IFCHR)|0744;
 169     stbuf->st_nlink = 1;
 170     stbuf->st_size = 0;
 171   }
 172   else return -ENOENT;
 173   return 0;
 174 }
 175
 176 /**
 177  * Creates a new device
 178  *  @param name Device name
 179  *  @return DevID
 180  */
 181 static int devfs_createdev(char *name,int shmid) {
 182   int devid = getnew_devid();
 183   if (devid>=0 && getdev_name(name)==NULL) {
 184     struct devlist_item *new = malloc(sizeof(struct devlist_item));
 185     struct shmid_ds shmid_ds;
 186     shmctl(shmid,IPC_STAT,&shmid_ds);
 187     new->id = devid;
 188     new->name = strdup(name);
 189     new->owner = rpc_curpid;
 190     new->shmbuf = shmat(shmid,NULL,0);
 191     new->bufsz = shmid_ds.shm_segsz;
 192     llist_push(devlist,new);
 193     return devid;
 194   }
 195   else {
 196     fprintf(stderr,"devfs: Could not create device: %s\n",name);
 197     return -1;
 198   }
 199 }
 200
 201 /**
 202  * Removes a device
 203  *  @param id DevID
 204  *  @return 0=success; -1=failure
 205  */
 206 static int devfs_removedev(int id) {
 207   struct devlist_item *dev = llist_get(devlist,getlid_devid(id));
 208   if (dev!=NULL && dev->owner==rpc_curpid) {
 209     llist_remove(devlist,getlid_devid(id));
 210     shmdt(dev->shmbuf);
 211     free(dev->name);
 212     free(dev);
 213     return 0;
 214   }
 215   return -1;
 216 }
 217
 218 /**
 219  * Initializes DevFS
 220  *  @param argc Number of arguments
 221  *  @param argv Values of arguments
 222  *  @return Return value
 223  */
 224 int main(int argc,char *argv[]) {
 225   devlist = llist_create();
 226   nextdevid = 1;
 227
 228   rpc_func(devfs_createdev,"$ii",NAME_MAX+sizeof(int));
 229   rpc_func(devfs_removedev,"i",sizeof(int));
 230
 231   struct fuse_operations devfs_oper = {
 232     .open = devfs_open,
 233     .release = devfs_close,
 234     .read = devfs_read,
 235     .write = devfs_write,
 236     .readdir = devfs_readdir,
 237     .getattr = devfs_getattr
 238   };
 239
 240   // fake argc/argv
 241   int fake_argc = 2;
 242   char *fake_argv[2] = { "devfs","/dev" };
 243   fuse_main(fake_argc,fake_argv,&devfs_oper,NULL);
 244
 245   return 0;
 246 }