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 <fcntl.h>
  12 #include <minix/type.h>
  13 #include <minix/safecopies.h>
  14 #include <minix/sys_config.h>
  15
  16 #include "log.h"
  17
  18 /*==========================================================================*
  19  *                              do_new_kmess                                *
  20  *==========================================================================*/
  21 PUBLIC int do_new_kmess(from)
  22 endpoint_t from;                                /* who sent this message? */
  23 {
  24 /* Notification for a new kernel message. */
  25   static struct kmessages kmess;                /* entire kmess structure */
  26   static char print_buf[_KMESS_BUF_SIZE];       /* copy new message here */
  27   int bytes;
  28   int i, r;
  29   int *prev_nextp;
  30
  31   static int kernel_prev_next = 0;
  32   static int tty_prev_next = 0;
  33
  34   if (from == TTY_PROC_NR)
  35   {
  36         cp_grant_id_t gid;
  37         message mess;
  38
  39         prev_nextp= &tty_prev_next;
  40         gid= cpf_grant_direct(TTY_PROC_NR, (vir_bytes)&kmess, sizeof(kmess),
  41                 CPF_WRITE);
  42         if (gid == -1)
  43         {
  44 #if 0
  45                 report("LOG","cpf_grant_direct failed for TTY", errno);
  46 #endif
  47                 return EDONTREPLY;
  48         }
  49
  50         /* Ask TTY driver for log output */
  51         mess.GETKM_GRANT= gid;
  52         mess.m_type = GET_KMESS_S;
  53         r= sendrec(TTY_PROC_NR, &mess);
  54         cpf_revoke(gid);
  55
  56         if (r == OK) r= mess.m_type;
  57         if (r != OK)
  58         {
  59                 report("LOG","couldn't get copy of kmessages from TTY", r);
  60                 return EDONTREPLY;
  61         }
  62   }
  63   else
  64   {
  65         /* Try to get a fresh copy of the buffer with kernel messages. */
  66         if ((r=sys_getkmessages(&kmess)) != OK) {
  67                 report("LOG","couldn't get copy of kmessages", r);
  68                 return EDONTREPLY;
  69         }
  70         prev_nextp= &kernel_prev_next;
  71   }
  72
  73   /* Print only the new part. Determine how many new bytes there are with
  74    * help of the current and previous 'next' index. Note that the kernel
  75    * buffer is circular. This works fine if less then KMESS_BUF_SIZE bytes
  76    * is new data; else we miss % KMESS_BUF_SIZE here.
  77    * Check for size being positive, the buffer might as well be emptied!
  78    */
  79   if (kmess.km_size > 0) {
  80       bytes = ((kmess.km_next + _KMESS_BUF_SIZE) - (*prev_nextp)) %
  81         _KMESS_BUF_SIZE;
  82       r= *prev_nextp;                           /* start at previous old */
  83       i=0;
  84       while (bytes > 0) {
  85           print_buf[i] = kmess.km_buf[(r%_KMESS_BUF_SIZE)];
  86           bytes --;
  87           r ++;
  88           i ++;
  89       }
  90       /* Now terminate the new message and save it in the log. */
  91       print_buf[i] = 0;
  92       log_append(print_buf, i);
  93   }
  94
  95   /* Almost done, store 'next' so that we can determine what part of the
  96    * kernel messages buffer to print next time a notification arrives.
  97    */
  98   *prev_nextp = kmess.km_next;
  99   return EDONTREPLY;
 100 }
 101
 102 /*===========================================================================*
 103  *                              do_diagnostics                               *
 104  *===========================================================================*/
 105 PUBLIC int do_diagnostics(message *m, int safe)
 106 {
 107 /* The LOG server handles all diagnostic messages from servers and device
 108  * drivers. It forwards the message to the TTY driver to display it to the
 109  * user. It also saves a copy in a local buffer so that messages can be
 110  * reviewed at a later time.
 111  */
 112   vir_bytes src;
 113   int count;
 114   char c;
 115   int i = 0, offset = 0;
 116   static char diagbuf[10240];
 117
 118   /* Also make a copy for the private buffer at the LOG server, so
 119    * that the messages can be reviewed at a later time.
 120    */
 121   src = (vir_bytes) m->DIAG_PRINT_BUF_G;
 122   count = m->DIAG_BUF_COUNT;
 123   while (count > 0 && i < sizeof(diagbuf)-1) {
 124       int r;
 125       if(safe) {
 126         r = sys_safecopyfrom(m->m_source, src, offset, (vir_bytes) &c, 1, D);
 127       } else {
 128         r = sys_datacopy(m->m_source, src+offset, SELF, (vir_bytes) &c, 1);
 129       }
 130       if(r != OK) break;
 131       offset ++;
 132       count --;
 133       diagbuf[i++] = c;
 134   }
 135   log_append(diagbuf, i);
 136
 137   if(m->m_type == ASYN_DIAGNOSTICS_OLD) return EDONTREPLY;
 138
 139   return OK;
 140 }