minix/lib/libfsdriver/fsdriver.c

   1
   2 #include "fsdriver.h"
   3
   4 /* Library-local variables. */
   5 dev_t fsdriver_device;
   6 ino_t fsdriver_root;
   7 int fsdriver_mounted = FALSE;
   8
   9 static int fsdriver_running;
  10
  11 /*
  12  * Process an incoming VFS request, and send a reply.  If the message is not
  13  * a file system request from VFS, pass it on to the generic message handler.
  14  * Multithreaded file systems should indicate that the reply is to be sent to
  15  * VFS asynchronously.
  16  */
  17 void
  18 fsdriver_process(const struct fsdriver * __restrict fdp,
  19         const message * __restrict m_ptr, int ipc_status, int asyn_reply)
  20 {
  21         message m_out;
  22         unsigned int call_nr;
  23         int r, transid;
  24
  25         /* Is this a file system request at all? */
  26         if (is_ipc_notify(ipc_status) || m_ptr->m_source != VFS_PROC_NR) {
  27                 if (fdp->fdr_other != NULL)
  28                         fdp->fdr_other(m_ptr, ipc_status);
  29
  30                 return; /* do not send a reply */
  31         }
  32
  33         /* Call the appropriate function. */
  34         transid = TRNS_GET_ID(m_ptr->m_type);
  35         call_nr = TRNS_DEL_ID(m_ptr->m_type);
  36
  37         memset(&m_out, 0, sizeof(m_out));
  38
  39         if (fsdriver_mounted || call_nr == REQ_READSUPER) {
  40                 call_nr -= FS_BASE;     /* unsigned; wrapping is intended */
  41
  42                 if (call_nr < NREQS && fsdriver_callvec[call_nr] != NULL)
  43                         r = (fsdriver_callvec[call_nr])(fdp, m_ptr, &m_out);
  44                 else
  45                         r = ENOSYS;
  46         } else
  47                 r = EINVAL;
  48
  49         /* Send a reply. */
  50         m_out.m_type = TRNS_ADD_ID(r, transid);
  51
  52         if (asyn_reply)
  53                 r = asynsend(m_ptr->m_source, &m_out);
  54         else
  55                 r = ipc_send(m_ptr->m_source, &m_out);
  56
  57         if (r != OK)
  58                 printf("fsdriver: sending reply failed (%d)\n", r);
  59
  60         if (fdp->fdr_postcall != NULL)
  61                 fdp->fdr_postcall();
  62 }
  63
  64 /*
  65  * Terminate the file server as soon as the file system has been unmounted.
  66  */
  67 void
  68 fsdriver_terminate(void)
  69 {
  70
  71         fsdriver_running = FALSE;
  72
  73         sef_cancel();
  74 }
  75
  76 /*
  77  * Main program of any file server task.
  78  */
  79 void
  80 fsdriver_task(struct fsdriver * fdp)
  81 {
  82         message mess;
  83         int r, ipc_status;
  84
  85         fsdriver_running = TRUE;
  86
  87         while (fsdriver_running || fsdriver_mounted) {
  88                 if ((r = sef_receive_status(ANY, &mess, &ipc_status)) != OK) {
  89                         if (r == EINTR)
  90                                 continue;       /* sef_cancel() was called */
  91
  92                         panic("fsdriver: sef_receive_status failed: %d", r);
  93                 }
  94
  95                 fsdriver_process(fdp, &mess, ipc_status, FALSE /*asyn_reply*/);
  96         }
  97 }