47 lines
1.6 KiB
C
47 lines
1.6 KiB
C
/* A server must occasionally print some message. It uses a simple version of
|
|
* printf() found in the system lib that calls kputc() to output characters.
|
|
* Printing is done with a call to the kernel, and not by going through FS.
|
|
*
|
|
* This routine can only be used by servers and device drivers. The kernel
|
|
* must define its own kputc(). Note that the log driver also defines its own
|
|
* kputc() to directly call the TTY instead of going through this library.
|
|
*/
|
|
|
|
#include "sysutil.h"
|
|
|
|
/*===========================================================================*
|
|
* kputc *
|
|
*===========================================================================*/
|
|
void kputc(c)
|
|
int c;
|
|
{
|
|
/* Accumulate another character. If 0 or buffer full, print it. */
|
|
static int buf_count; /* # characters in the buffer */
|
|
static char print_buf[80]; /* output is buffered here */
|
|
message m;
|
|
|
|
if ((c == 0 && buf_count > 0) || buf_count == sizeof(print_buf)) {
|
|
int procs[] = OUTPUT_PROCS_ARRAY;
|
|
int p;
|
|
|
|
for(p = 0; procs[p] != NONE; p++) {
|
|
/* Send the buffer to this output driver. */
|
|
m.DIAG_BUF_COUNT = buf_count;
|
|
m.DIAG_PRINT_BUF = print_buf;
|
|
m.DIAG_ENDPT = SELF;
|
|
m.m_type = DIAGNOSTICS;
|
|
(void) _sendrec(procs[p], &m);
|
|
}
|
|
buf_count = 0;
|
|
|
|
/* If the output fails, e.g., due to an ELOCKED, do not retry output
|
|
* at the FS as if this were a normal user-land printf(). This may
|
|
* result in even worse problems.
|
|
*/
|
|
}
|
|
if (c != 0) {
|
|
|
|
/* Append a single character to the output buffer. */
|
|
print_buf[buf_count++] = c;
|
|
}
|
|
}
|