servers/vm/vfs.c

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