3cc092ff06
now used for printing diagnostic messages through the kernel message buffer. this lets processes print diagnostics without sending messages to tty and log directly, simplifying the message protocol a lot and reducing difficulties with deadlocks and other situations in which diagnostics are blackholed (e.g. grants don't work). this makes DIAGNOSTICS(_S), ASYN_DIAGNOSTICS and DIAG_REPL obsolete, although tty and log still accept the codes for 'old' binaries. This also simplifies diagnostics in several servers and drivers - only tty needs its own kputc() now. . simplifications in vfs, and some effort to get the vnode references right (consistent) even during shutdown. m_mounted_on is now NULL for root filesystems (!) (the original and new root), a less awkward special case than 'm_mounted_on == m_root_node'. root now has exactly one reference, to root, if no files are open, just like all other filesystems. m_driver_e is unused.
34 lines
1.1 KiB
C
34 lines
1.1 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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static char print_buf[DIAG_BUFSIZE]; /* output is buffered here */
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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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message m;
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if ((c == 0 && buf_count > 0) || buf_count == sizeof(print_buf)) {
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sys_sysctl(SYSCTL_CODE_DIAG, print_buf, buf_count);
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buf_count = 0;
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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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