servers/vm/vfs.c

   1
   2 /* Sending requests to VFS and handling the replies.  */
   3
   4 #define _SYSTEM 1
   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/minlib.h>
  13 #include <minix/type.h>
  14 #include <minix/ipc.h>
  15 #include <minix/sysutil.h>
  16 #include <minix/syslib.h>
  17 #include <minix/type.h>
  18 #include <minix/bitmap.h>
  19 #include <string.h>
  20 #include <errno.h>
  21 #include <env.h>
  22 #include <unistd.h>
  23 #include <assert.h>
  24 #include <sys/param.h>
  25
  26 #include "proto.h"
  27 #include "glo.h"
  28 #include "util.h"
  29 #include "region.h"
  30 #include "sanitycheck.h"
  31
  32 #define STATELEN 70
  33
  34 static struct vfs_request_node {
  35         message                 reqmsg;
  36         char                    reqstate[STATELEN];
  37         void                    *opaque;
  38         endpoint_t              who;
  39         int                     req_id;
  40         vfs_callback_t          callback;
  41         struct vfs_request_node *next;
  42 } *first_queued, *active;
  43
  44 static void activate(void)
  45 {
  46         assert(!active);
  47         assert(first_queued);
  48
  49         active = first_queued;
  50         first_queued = first_queued->next;
  51
  52         if(asynsend3(VFS_PROC_NR, &active->reqmsg, AMF_NOREPLY) != OK)
  53                 panic("VM: asynsend to VFS failed");
  54 }
  55
  56 #define ID_MAX LONG_MAX
  57
  58 /*===========================================================================*
  59  *                              vfs_request                                 *
  60  *===========================================================================*/
  61 int vfs_request(int reqno, int fd, struct vmproc *vmp, u64_t offset, u32_t len,
  62         vfs_callback_t reply_callback, void *cbarg, void *state, int statelen)
  63 {
  64 /* Perform an asynchronous request to VFS.
  65  * We send a message of type VFS_VMCALL to VFS. VFS will respond
  66  * with message type VM_VFS_REPLY. We send the request asynchronously
  67  * and then handle the reply as it if were a VM_VFS_REPLY request.
  68  */
  69         message *m;
  70         static int reqid = 0;
  71         struct vfs_request_node *reqnode;
  72
  73         reqid++;
  74
  75         assert(statelen <= STATELEN);
  76
  77         if(!SLABALLOC(reqnode)) {
  78                 printf("vfs_request: no memory for request node\n");
  79                 return ENOMEM;
  80         }
  81
  82         m = &reqnode->reqmsg;
  83         memset(m, 0, sizeof(*m));
  84         m->m_type = VFS_VMCALL;
  85         m->VFS_VMCALL_REQ = reqno;
  86         m->VFS_VMCALL_FD = fd;
  87         m->VFS_VMCALL_REQID = reqid;
  88         m->VFS_VMCALL_ENDPOINT = vmp->vm_endpoint;
  89         m->VFS_VMCALL_OFFSET = offset;
  90         m->VFS_VMCALL_LENGTH = len;
  91
  92         reqnode->who = vmp->vm_endpoint;
  93         reqnode->req_id = reqid;
  94         reqnode->next = first_queued;
  95         reqnode->callback = reply_callback;
  96         reqnode->opaque = cbarg;
  97         if(state) memcpy(reqnode->reqstate, state, statelen);
  98         first_queued = reqnode;
  99
 100         /* Send the request message if none pending. */
 101         if(!active)
 102                 activate();
 103
 104         return OK;
 105 }
 106
 107 /*===========================================================================*
 108  *                              do_vfs_reply                                 *
 109  *===========================================================================*/
 110 int do_vfs_reply(message *m)
 111 {
 112 /* VFS has handled a VM request and VFS has replied. It must be the
 113  * active request.
 114  */
 115         struct vfs_request_node *orignode = active;
 116         vfs_callback_t req_callback;
 117         void *cbarg;
 118         int n;
 119         struct vmproc *vmp;
 120
 121         assert(active);
 122         assert(active->req_id == m->VMV_REQID);
 123
 124         /* the endpoint may have exited */
 125         if(vm_isokendpt(m->VMV_ENDPOINT, &n) != OK)
 126                 vmp = NULL;
 127         else    vmp = &vmproc[n];
 128
 129         req_callback = active->callback;
 130         cbarg = active->opaque;
 131         active = NULL;
 132
 133         /* Invoke requested reply-callback within VM. */
 134         if(req_callback) req_callback(vmp, m, cbarg, orignode->reqstate);
 135
 136         SLABFREE(orignode);
 137
 138         /* Send the next request message if any and not re-activated. */
 139         if(first_queued && !active)
 140                 activate();
 141
 142         return SUSPEND; /* don't reply to the reply */
 143 }
 144