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 #if 0
  44                 report("LOG","cpf_grant_direct failed for TTY", errno);
  45 #endif
  46                 return EDONTREPLY;
  47         }
  48
  49         /* Ask TTY driver for log output */
  50         mess.GETKM_GRANT= gid;
  51         mess.m_type = GET_KMESS_S;
  52         r= sendrec(TTY_PROC_NR, &mess);
  53         cpf_revoke(gid);
  54
  55         if (r == OK) r= mess.m_type;
  56         if (r != OK)
  57         {
  58                 report("LOG","couldn't get copy of kmessages from TTY", r);
  59                 return EDONTREPLY;
  60         }
  61   }
  62   else
  63   {
  64         /* Try to get a fresh copy of the buffer with kernel messages. */
  65         if ((r=sys_getkmessages(&kmess)) != OK) {
  66                 report("LOG","couldn't get copy of kmessages", r);
  67                 return EDONTREPLY;
  68         }
  69         prev_nextp= &kernel_prev_next;
  70   }
  71
  72   /* Print only the new part. Determine how many new bytes there are with
  73    * help of the current and previous 'next' index. Note that the kernel
  74    * buffer is circular. This works fine if less then KMESS_BUF_SIZE bytes
  75    * is new data; else we miss % KMESS_BUF_SIZE here.
  76    * Check for size being positive, the buffer might as well be emptied!
  77    */
  78   if (kmess.km_size > 0) {
  79       bytes = ((kmess.km_next + _KMESS_BUF_SIZE) - (*prev_nextp)) %
  80         _KMESS_BUF_SIZE;
  81       r= *prev_nextp;                           /* start at previous old */
  82       i=0;
  83       while (bytes > 0) {
  84           print_buf[i] = kmess.km_buf[(r%_KMESS_BUF_SIZE)];
  85           bytes --;
  86           r ++;
  87           i ++;
  88       }
  89       /* Now terminate the new message and save it in the log. */
  90       print_buf[i] = 0;
  91       log_append(print_buf, i);
  92   }
  93
  94   /* Almost done, store 'next' so that we can determine what part of the
  95    * kernel messages buffer to print next time a notification arrives.
  96    */
  97   *prev_nextp = kmess.km_next;
  98   return EDONTREPLY;
  99 }
 100
 101 /*===========================================================================*
 102  *                              do_diagnostics                               *
 103  *===========================================================================*/
 104 PUBLIC int do_diagnostics(message *m, int safe)
 105 {
 106 /* The LOG server handles all diagnostic messages from servers and device
 107  * drivers. It forwards the message to the TTY driver to display it to the
 108  * user. It also saves a copy in a local buffer so that messages can be
 109  * reviewed at a later time.
 110  */
 111   vir_bytes src;
 112   int count;
 113   char c;
 114   int i = 0, offset = 0;
 115   static char diagbuf[10240];
 116
 117   /* Also make a copy for the private buffer at the LOG server, so
 118    * that the messages can be reviewed at a later time.
 119    */
 120   src = (vir_bytes) m->DIAG_PRINT_BUF_G;
 121   count = m->DIAG_BUF_COUNT;
 122   while (count > 0 && i < sizeof(diagbuf)-1) {
 123       int r;
 124       if(safe) {
 125         r = sys_safecopyfrom(m->m_source, src, offset, (vir_bytes) &c, 1, D);
 126       } else {
 127         r = sys_datacopy(m->m_source, src+offset, SELF, (vir_bytes) &c, 1);
 128       }
 129       if(r != OK) break;
 130       offset ++;
 131       count --;
 132       diagbuf[i++] = c;
 133   }
 134   log_append(diagbuf, i);
 135
 136   if(m->m_type == ASYN_DIAGNOSTICS_OLD) return EDONTREPLY;
 137
 138   return OK;
 139 }