minix/servers/vfs/kputc.c

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/* 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"
#include "proto.h"
#include "glo.h"
#define OVERFLOW_STR "[...]\n"
#define PRINTPROCS (sizeof(procs)/sizeof(procs[0]))
static char print_buf[80]; /* output is buffered here */
int kputc_use_private_grants= 0;
static int buf_count = 0; /* # characters in the buffer */
static int buf_offset = 0; /* Start of current line in buffer */
static int procs[] = OUTPUT_PROCS_ARRAY;
static cp_grant_id_t printgrants[PRINTPROCS];
static int procbusy[PRINTPROCS];
static int do_flush = FALSE;
static int overflow = FALSE;
/*===========================================================================*
* kputc *
*===========================================================================*/
void kputc(c)
int c;
{
/* Accumulate another character. If 0 or buffer full, print it. */
int p;
message m;
static int firstprint = 1;
if (c == 0)
{
if (buf_count > buf_offset)
do_flush= TRUE;
}
else if (buf_count >= sizeof(print_buf))
{
overflow= TRUE;
if (buf_count > buf_offset)
do_flush= TRUE;
}
else
print_buf[buf_count++] = c;
if (!do_flush || buf_offset != 0)
return;
buf_offset= buf_count;
if (kputc_use_private_grants)
{
for (p= 0; p<PRINTPROCS; p++)
printgrants[p]= GRANT_INVALID;
firstprint= 0;
}
if(firstprint) {
for(p = 0; procs[p] != NONE; p++) {
printgrants[p] = GRANT_INVALID;
}
firstprint = 0;
/* First time? Initialize grant table;
* Grant printing processes read copy access to our
* print buffer forever. (So buffer can't be on stack!)
*/
for(p = 0; procs[p] != NONE; p++) {
printgrants[p] = cpf_grant_direct(procs[p],
(vir_bytes) print_buf,
sizeof(print_buf), CPF_READ);
}
}
do_flush= FALSE;
for(p = 0; procs[p] != NONE; p++) {
/* Send the buffer to this output driver. */
m.DIAG_BUF_COUNT = buf_count;
if(GRANT_VALID(printgrants[p])) {
m.m_type = DIAGNOSTICS_S;
m.DIAG_PRINT_BUF_G = (char *) printgrants[p];
} else {
m.m_type = DIAGNOSTICS;
m.DIAG_PRINT_BUF_G = print_buf;
}
if (procs[p] == LOG_PROC_NR)
{
procbusy[p]= TRUE;
(void) asynsend(procs[p], &m);
}
else
{
sendrec(procs[p], &m);
}
}
}
PUBLIC void diag_repl()
{
endpoint_t driver_e;
int p;
driver_e= m_in.m_source;
/* Find busy flag to clear */
for(p = 0; procs[p] != NONE; p++)
{
if (procs[p] == driver_e)
break;
}
if (procs[p] == NONE)
{
/* Message from wrong source */
return;
}
procbusy[p]= FALSE;
/* Wait for more replies? */
for(p = 0; procs[p] != NONE; p++)
{
if (procbusy[p])
return;
}
if (buf_count > buf_offset)
{
memmove(&print_buf[0], &print_buf[buf_offset],
buf_count-buf_offset);
}
buf_count -= buf_offset;
buf_offset= 0;
if (overflow)
{
if (buf_count + sizeof(OVERFLOW_STR) > sizeof(print_buf))
buf_count= sizeof(print_buf)-sizeof(OVERFLOW_STR);
overflow= FALSE;
do_flush= FALSE;
printf("%s", OVERFLOW_STR);
}
kputc(0);
}