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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*
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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 log driver also defines its own
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* kputc() to directly call the TTY instead of going through this library.
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*/
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#include "sysutil.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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int procs[] = OUTPUT_PROCS_ARRAY;
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int p;
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for(p = 0; procs[p] != NONE; p++) {
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/* Send the buffer to this output driver. */
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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_ENDPT = SELF;
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m.m_type = DIAGNOSTICS;
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(void) _sendrec(procs[p], &m);
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}
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buf_count = 0;
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/* If the output fails, e.g., due to an ELOCKED, do not retry output
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* at the FS as if this were a normal user-land printf(). This may
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* result in even worse problems.
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*/
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}
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if (c != 0) {
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/* Append a single character to the output buffer. */
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print_buf[buf_count++] = c;
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}
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}
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