58 lines
2.0 KiB
C
58 lines
2.0 KiB
C
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/* This file handle diagnostic output that is sent to the LOG driver. Output
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* can be either from the kernel, or from other system processes. Output from
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* system processes is also routed through the kernel. The kernel notifies
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* this driver with a SIGKMESS signal if any messages are available.
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*
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* Changes:
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* 21 July 2005: Created (Jorrit N. Herder)
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*/
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#include "log.h"
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#include <assert.h>
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extern struct minix_kerninfo *_minix_kerninfo;
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/*==========================================================================*
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* do_new_kmess *
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*==========================================================================*/
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void do_new_kmess(void)
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{
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/* Notification for a new kernel message. */
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static struct kmessages *kmess; /* entire kmess structure */
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static char print_buf[_KMESS_BUF_SIZE]; /* copy new message here */
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int i, r, next, bytes;
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static int prev_next = 0;
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assert(_minix_kerninfo);
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kmess = _minix_kerninfo->kmessages;
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/* Print only the new part. Determine how many new bytes there are with
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* help of the current and previous 'next' index. Note that the kernel
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* buffer is circular. This works fine if less than KMESS_BUF_SIZE bytes
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* are new data; else we miss % KMESS_BUF_SIZE here. Obtain 'next' only
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* once, since we are operating on shared memory here.
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* Check for size being positive, the buffer might as well be emptied!
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*/
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next = kmess->km_next;
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bytes = ((next + _KMESS_BUF_SIZE) - prev_next) % _KMESS_BUF_SIZE;
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if (bytes > 0) {
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r= prev_next; /* start at previous old */
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i=0;
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while (bytes > 0) {
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print_buf[i] = kmess->km_buf[(r%_KMESS_BUF_SIZE)];
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bytes --;
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r ++;
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i ++;
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}
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/* Now terminate the new message and save it in the log. */
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print_buf[i] = 0;
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log_append(print_buf, i);
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}
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/* Almost done, store 'next' so that we can determine what part of the
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* kernel messages buffer to print next time a notification arrives.
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*/
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prev_next = next;
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}
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