servers/vm/vfs.c

   1
   2 #define _SYSTEM 1
   3
   4 #define VERBOSE 0
   5
   6 #include <minix/callnr.h>
   7 #include <minix/com.h>
   8 #include <minix/config.h>
   9 #include <minix/const.h>
  10 #include <minix/ds.h>
  11 #include <minix/endpoint.h>
  12 #include <minix/keymap.h>
  13 #include <minix/minlib.h>
  14 #include <minix/type.h>
  15 #include <minix/ipc.h>
  16 #include <minix/sysutil.h>
  17 #include <minix/syslib.h>
  18 #include <minix/safecopies.h>
  19 #include <minix/bitmap.h>
  20
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <env.h>
  24 #include <stdio.h>
  25
  26 #include "glo.h"
  27 #include "proto.h"
  28 #include "util.h"
  29
  30 /*===========================================================================*
  31  *                              register_callback                            *
  32  *===========================================================================*/
  33 PRIVATE void register_callback(struct vmproc *for_who, callback_t callback,
  34         int callback_type)
  35 {
  36         if(for_who->vm_callback) {
  37                 vm_panic("register_callback: callback already registered",
  38                         for_who->vm_callback_type);
  39         }
  40         for_who->vm_callback = callback;
  41         for_who->vm_callback_type = callback_type;
  42
  43         return;
  44 }
  45
  46 /*===========================================================================*
  47  *                              vfs_open                                     *
  48  *===========================================================================*/
  49 PUBLIC int vfs_open(struct vmproc *for_who, callback_t callback,
  50         cp_grant_id_t filename_gid, int filename_len, int flags, int mode)
  51 {
  52         static message m;
  53         int r;
  54
  55         register_callback(for_who, callback, VM_VFS_REPLY_OPEN);
  56
  57         m.m_type = VM_VFS_OPEN;
  58         m.VMVO_NAME_GRANT = filename_gid;
  59         m.VMVO_NAME_LENGTH = filename_len;
  60         m.VMVO_FLAGS = flags;
  61         m.VMVO_MODE = mode;
  62         m.VMVO_ENDPOINT = for_who->vm_endpoint;
  63
  64         if((r=asynsend(VFS_PROC_NR, &m)) != OK) {
  65                 vm_panic("vfs_open: asynsend failed", r);
  66         }
  67
  68         return r;
  69 }
  70
  71 /*===========================================================================*
  72  *                              vfs_close                                    *
  73  *===========================================================================*/
  74 PUBLIC int vfs_close(struct vmproc *for_who, callback_t callback, int fd)
  75 {
  76         static message m;
  77         int r;
  78
  79         register_callback(for_who, callback, VM_VFS_REPLY_CLOSE);
  80
  81         m.m_type = VM_VFS_CLOSE;
  82         m.VMVC_ENDPOINT = for_who->vm_endpoint;
  83         m.VMVC_FD = fd;
  84
  85         if((r=asynsend(VFS_PROC_NR, &m)) != OK) {
  86                 vm_panic("vfs_close: asynsend failed", r);
  87         }
  88
  89         return r;
  90 }
  91
  92 /*===========================================================================*
  93  *                              do_vfs_reply                            *
  94  *===========================================================================*/
  95 PUBLIC int do_vfs_reply(message *m)
  96 {
  97 /* Reply to a request has been received from vfs. Handle it. First verify
  98  * and look up which process, identified by endpoint, this is about.
  99  * Then call the callback function that was registered when the request
 100  * was done. Return result to vfs.
 101  */
 102         endpoint_t ep;
 103         struct vmproc *vmp;
 104         int procno;
 105         callback_t cb;
 106         ep = m->VMV_ENDPOINT;
 107         if(vm_isokendpt(ep, &procno) != OK) {
 108                 printf("VM:do_vfs_reply: reply %d about invalid endpoint %d\n",
 109                         m->m_type, ep);
 110                 vm_panic("do_vfs_reply: invalid endpoint from vfs", NO_NUM);
 111         }
 112         vmp = &vmproc[procno];
 113         if(!vmp->vm_callback) {
 114                 printf("VM:do_vfs_reply: reply %d: endpoint %d not waiting\n",
 115                         m->m_type, ep);
 116                 vm_panic("do_vfs_reply: invalid endpoint from vfs", NO_NUM);
 117         }
 118         if(vmp->vm_callback_type != m->m_type) {
 119                 printf("VM:do_vfs_reply: reply %d unexpected for endpoint %d\n"
 120                   " (expecting %d)\n", m->m_type, ep, vmp->vm_callback_type);
 121                 vm_panic("do_vfs_reply: invalid reply from vfs", NO_NUM);
 122         }
 123         if(vmp->vm_flags & VMF_EXITING) {
 124                 /* This is not fatal or impossible, but the callback
 125                  * function has to realize it shouldn't do any PM or
 126                  * VFS calls for this process.
 127                  */
 128                 printf("VM:do_vfs_reply: reply %d for EXITING endpoint %d\n",
 129                   m->m_type, ep);
 130         }
 131
 132         /* All desired callback state has been used, so save and reset
 133          * the callback. This allows the callback to register another
 134          * one.
 135          */
 136         cb = vmp->vm_callback;
 137         vmp->vm_callback = NULL;
 138         cb(vmp, m);
 139         return SUSPEND;
 140 }
 141