48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
/* A server must occasionally print some message. It uses a simple version of
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* printf() found in the system lib that calls kputc() to output characters.
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* Printing is done with a call to the kernel, and not by going through FS.
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* This way system messages end up in the kernel messages buffer and can be
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* reviewed at a later time.
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*
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* This routine can only be used by servers and device drivers. The kernel
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* must define its own kputc(). Note that the IS also defines its own kputc()
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* to directly call the TTY instead of the kernel, because it does not want
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* to pollute the kernel message buffer with its debug dumps.
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*/
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#include "syslib.h"
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#include <minix/callnr.h>
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#include <minix/minlib.h>
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/*===========================================================================*
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* kputc *
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*===========================================================================*/
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void kputc(c)
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int c;
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{
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/* Accumulate another character. If 0 or buffer full, print it. */
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static int buf_count; /* # characters in the buffer */
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static char print_buf[80]; /* output is buffered here */
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message m;
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if ((c == 0 && buf_count > 0) || buf_count == sizeof(print_buf)) {
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/* Send the buffer to the system task, or, if this process is not a
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* server yet, to standard error.
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*/
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m.DIAG_BUF_COUNT = buf_count;
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m.DIAG_PRINT_BUF = print_buf;
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m.DIAG_PROC_NR = SELF;
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m.m_type = DIAGNOSTICS;
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if (_sendrec(TTY, &m) != 0) {
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m.m1_i1 = 2;
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m.m1_i2 = buf_count;
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m.m1_p1 = print_buf;
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m.m_type = WRITE;
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(void) _sendrec(FS, &m);
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}
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buf_count = 0;
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}
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if (c != 0) print_buf[buf_count++] = c;
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}
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