system/kernel/fs/devfs.c

   1 /*
   2 Copyright (C) 2008  Mathias Gottschlag
   3
   4 Permission is hereby granted, free of charge, to any person obtaining a copy of
   5 this software and associated documentation files (the "Software"), to deal in the
   6 Software without restriction, including without limitation the rights to use,
   7 copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
   8 Software, and to permit persons to whom the Software is furnished to do so,
   9 subject to the following conditions:
  10
  11 The above copyright notice and this permission notice shall be included in all
  12 copies or substantial portions of the Software.
  13
  14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
  15 INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
  16 PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  17 HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  18 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  19 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20 */
  21
  22 #include "fs/devfs.h"
  23 #include "fs/request.h"
  24 #include "ke/errors.h"
  25 #include "ke/debug.h"
  26 #include <string.h>
  27 #include <stdlib.h>
  28
  29 typedef struct
  30 {
  31         FsFile file;
  32         uint32_t index;
  33 } KeDevFSFile;
  34
  35 static FsFileSystemDriver devfs;
  36 static FsFileSystem fs;
  37
  38 static FsDeviceFile **devfsfiles = 0;
  39 static FsFile **files = 0;
  40 static uint32_t devfsfile_count = 0;
  41
  42 static FsFile *fsDevFSOpen(FsFileSystem *fs, const char *path)
  43 {
  44         // Search for file
  45         uint32_t fileindex = 0xFFFFFFFF;
  46         uint32_t i;
  47         for (i = 0; i < devfsfile_count; i++)
  48         {
  49                 if (!strcmp(devfsfiles[i]->path, path))
  50                 {
  51                         fileindex = i;
  52                         break;
  53                 }
  54         }
  55         if (fileindex == 0xFFFFFFFF) return 0;
  56         // Open existing file
  57         if (files[fileindex]) return files[fileindex];
  58         // Create file structure
  59         KeDevFSFile *file = malloc(sizeof(KeDevFSFile));
  60         files[fileindex] = &file->file;
  61         memset(file, 0, sizeof(FsFile));
  62         file->file.fs = fs;
  63         file->index = fileindex;
  64         return files[fileindex];
  65 }
  66
  67 static FsFileSystem *fsDevFSMount(struct FsFileSystemDriver *driver,
  68         const char *path, const char *device, uint32_t flags)
  69 {
  70         if (fs.path) return 0;
  71         fs.path = strdup(path);
  72         return &fs;
  73 }
  74 static int fsDevFSRequest(struct FsFileSystem *fs, struct FsRequest *request)
  75 {
  76         switch (request->type)
  77         {
  78                 // Open/close files at once
  79                 case FS_REQUEST_OPEN:
  80                         {
  81                                 request->file = fsDevFSOpen(fs, request->buffer);
  82                                 if (!request->file)
  83                                 {
  84                                         request->status = KE_ERROR_UNKNOWN;
  85                                         request->return_value = -1;
  86                                 }
  87                                 else
  88                                 {
  89                                         uint32_t fileindex = ((KeDevFSFile*)request->file)->index;
  90                                         devfsfiles[fileindex]->query_request(devfsfiles[fileindex], request);
  91                                 }
  92                                 fsFinishRequest(request);
  93                         }
  94                         return 0;
  95                 case FS_REQUEST_CLOSE:
  96                         {
  97                                 uint32_t fileindex = ((KeDevFSFile*)request->file)->index;
  98                                 devfsfiles[fileindex]->query_request(devfsfiles[fileindex], request);
  99                                 fsFinishRequest(request);
 100                         }
 101                         return 0;
 102                         // Pass other requests to the driver
 103                 default:
 104                         {
 105                                 uint32_t fileindex = ((KeDevFSFile*)request->file)->index;
 106                                 if (!devfsfiles[fileindex]->query_request)
 107                                 {
 108                                         kePrint("devfs: No request handler.\n");
 109                                         return KE_ERROR_UNKNOWN;
 110                                 }
 111                                 return devfsfiles[fileindex]->query_request(devfsfiles[fileindex], request);
 112                         }
 113         }
 114 }
 115
 116 static int fsDevFSUnmount(FsFileSystem *fs)
 117 {
 118         free(fs->path);
 119         fs->path = 0;
 120         return 0;
 121 }
 122
 123 int fsInitDevFS(void)
 124 {
 125         memset(&fs, 0, sizeof(fs));
 126         fs.driver = &devfs;
 127         fs.unmount = fsDevFSUnmount;
 128         fs.query_request = fsDevFSRequest;
 129
 130         // Register file system driver
 131         devfs.flags = FS_DRIVER_SINGLE | FS_DRIVER_NOMOUNT | FS_DRIVER_NODATA;
 132         devfs.mount = fsDevFSMount;
 133         fsRegisterDriver(&devfs, "devfs");
 134         return 0;
 135 }
 136
 137 int fsCreateDeviceFile(FsDeviceFile *file)
 138 {
 139         // Add file to file list
 140         devfsfiles = realloc(devfsfiles, (devfsfile_count + 1) * sizeof(FsDeviceFile*));
 141         files = realloc(files, (devfsfile_count + 1) * sizeof(FsFile*));
 142         devfsfiles[devfsfile_count] = file;
 143         files[devfsfile_count] = 0;
 144         devfsfile_count++;
 145         kePrint("Created device: %s\n", file->path);
 146         return 0;
 147 }
 148 int fsDestroyDeviceFile(FsDeviceFile *file)
 149 {
 150         // Search for file
 151         uint32_t fileindex = 0xFFFFFFFF;
 152         uint32_t i;
 153         for (i = 0; i < devfsfile_count; i++)
 154         {
 155                 if (devfsfiles[i] == file)
 156                 {
 157                         fileindex = i;
 158                         break;
 159                 }
 160         }
 161         if (fileindex == 0xFFFFFFFF) return KE_ERROR_UNKNOWN;
 162         // Close open file handles
 163         // Remove from file list
 164         memmove(devfsfiles + fileindex, devfsfiles + fileindex + 1,
 165                 (devfsfile_count - fileindex - 1) * sizeof(FsDeviceFile*));
 166         devfsfiles = realloc(devfsfiles, (devfsfile_count - 1) * sizeof(FsDeviceFile*));
 167         memmove(files + fileindex, files + i + 1,
 168                 (devfsfile_count - fileindex - 1) * sizeof(FsFile*));
 169         files = realloc(files, (devfsfile_count - 1) * sizeof(FsFile*));
 170         devfsfile_count--;
 171         for (i = fileindex; i < devfsfile_count; i++)
 172         {
 173                 ((KeDevFSFile*)files[i])->index = i;
 174         }
 175         return 0;
 176 }
 177