drivers/log/diag.c

   1 /* This file handle diagnostic output that is directly sent to the LOG driver.
   2  * This output can either be a kernel message (announced through a SYS_EVENT
   3  * with a SIGKMESS in the signal set) or output from another system process
   4  * (announced through a DIAGNOSTICS message).
   5  *
   6  * Changes:
   7  *      21 July 2005:   Created  (Jorrit N. Herder)
   8  */
   9
  10 #include <stdio.h>
  11 #include <minix/type.h>
  12 #include <minix/safecopies.h>
  13 #include <minix/sys_config.h>
  14
  15 #include "log.h"
  16
  17 /*==========================================================================*
  18  *                              do_new_kmess                                *
  19  *==========================================================================*/
  20 PUBLIC int do_new_kmess(from)
  21 endpoint_t from;                                /* who sent this message? */
  22 {
  23 /* Notification for a new kernel message. */
  24   static struct kmessages kmess;                /* entire kmess structure */
  25   static char print_buf[_KMESS_BUF_SIZE];       /* copy new message here */
  26   int bytes;
  27   int i, r;
  28   int *prev_nextp;
  29
  30   static int kernel_prev_next = 0;
  31   static int tty_prev_next = 0;
  32
  33   if (from == TTY_PROC_NR)
  34   {
  35         cp_grant_id_t gid;
  36         message mess;
  37
  38         prev_nextp= &tty_prev_next;
  39         gid= cpf_grant_direct(TTY_PROC_NR, (vir_bytes)&kmess, sizeof(kmess),
  40                 CPF_WRITE);
  41         if (gid == -1)
  42         {
  43                 return EDONTREPLY;
  44         }
  45
  46         /* Ask TTY driver for log output */
  47         mess.GETKM_GRANT= gid;
  48         mess.m_type = GET_KMESS_S;
  49         r= sendrec(TTY_PROC_NR, &mess);
  50         cpf_revoke(gid);
  51
  52         if (r == OK) r= mess.m_type;
  53         if (r != OK)
  54         {
  55                 printf("log: couldn't get copy of kmessages from TTY: %d\n", r);
  56                 return EDONTREPLY;
  57         }
  58   }
  59   else
  60   {
  61         /* Try to get a fresh copy of the buffer with kernel messages. */
  62         if ((r=sys_getkmessages(&kmess)) != OK) {
  63                 printf("log: couldn't get copy of kmessages: %d\n", r);
  64                 return EDONTREPLY;
  65         }
  66         prev_nextp= &kernel_prev_next;
  67   }
  68
  69   /* Print only the new part. Determine how many new bytes there are with
  70    * help of the current and previous 'next' index. Note that the kernel
  71    * buffer is circular. This works fine if less then KMESS_BUF_SIZE bytes
  72    * is new data; else we miss % KMESS_BUF_SIZE here.
  73    * Check for size being positive, the buffer might as well be emptied!
  74    */
  75   if (kmess.km_size > 0) {
  76       bytes = ((kmess.km_next + _KMESS_BUF_SIZE) - (*prev_nextp)) %
  77         _KMESS_BUF_SIZE;
  78       r= *prev_nextp;                           /* start at previous old */
  79       i=0;
  80       while (bytes > 0) {
  81           print_buf[i] = kmess.km_buf[(r%_KMESS_BUF_SIZE)];
  82           bytes --;
  83           r ++;
  84           i ++;
  85       }
  86       /* Now terminate the new message and save it in the log. */
  87       print_buf[i] = 0;
  88       log_append(print_buf, i);
  89   }
  90
  91   /* Almost done, store 'next' so that we can determine what part of the
  92    * kernel messages buffer to print next time a notification arrives.
  93    */
  94   *prev_nextp = kmess.km_next;
  95   return EDONTREPLY;
  96 }
  97
  98 /*===========================================================================*
  99  *                              do_diagnostics                               *
 100  *===========================================================================*/
 101 PUBLIC int do_diagnostics(message *m, int safe)
 102 {
 103 /* The LOG server handles all diagnostic messages from servers and device
 104  * drivers. It forwards the message to the TTY driver to display it to the
 105  * user. It also saves a copy in a local buffer so that messages can be
 106  * reviewed at a later time.
 107  */
 108   vir_bytes src;
 109   int count;
 110   char c;
 111   int i = 0, offset = 0;
 112   static char diagbuf[10240];
 113
 114   /* Also make a copy for the private buffer at the LOG server, so
 115    * that the messages can be reviewed at a later time.
 116    */
 117   src = (vir_bytes) m->DIAG_PRINT_BUF_G;
 118   count = m->DIAG_BUF_COUNT;
 119   while (count > 0 && i < sizeof(diagbuf)-1) {
 120       int r;
 121       if(safe) {
 122         r = sys_safecopyfrom(m->m_source, src, offset, (vir_bytes) &c, 1, D);
 123       } else {
 124         r = sys_datacopy(m->m_source, src+offset, SELF, (vir_bytes) &c, 1);
 125       }
 126       if(r != OK) break;
 127       offset ++;
 128       count --;
 129       diagbuf[i++] = c;
 130   }
 131   log_append(diagbuf, i);
 132
 133   if(m->m_type == ASYN_DIAGNOSTICS_OLD) return EDONTREPLY;
 134
 135   return OK;
 136 }