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.
140 lines
4 KiB
C
140 lines
4 KiB
C
/* This file handle diagnostic output that is directly sent to the LOG driver.
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* This output can either be a kernel message (announced through a SYS_EVENT
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* with a SIGKMESS in the signal set) or output from another system process
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* (announced through a DIAGNOSTICS message).
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*
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* Changes:
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* 21 July 2005: Created (Jorrit N. Herder)
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*/
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#include <stdio.h>
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#include <fcntl.h>
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#include <minix/type.h>
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#include <minix/safecopies.h>
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#include <minix/sys_config.h>
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#include "log.h"
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/*==========================================================================*
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* do_new_kmess *
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*==========================================================================*/
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PUBLIC int do_new_kmess(m)
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message *m; /* notification message */
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{
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/* Notification for a new kernel message. */
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static struct kmessages kmess; /* entire kmess structure */
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static char print_buf[_KMESS_BUF_SIZE]; /* copy new message here */
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int bytes;
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int i, r;
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int *prev_nextp;
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static int kernel_prev_next = 0;
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static int tty_prev_next = 0;
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if (m->m_source == TTY_PROC_NR)
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{
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cp_grant_id_t gid;
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message mess;
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prev_nextp= &tty_prev_next;
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gid= cpf_grant_direct(TTY_PROC_NR, (vir_bytes)&kmess, sizeof(kmess),
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CPF_WRITE);
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if (gid == -1)
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{
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#if 0
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report("LOG","cpf_grant_direct failed for TTY", errno);
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#endif
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return EDONTREPLY;
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}
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/* Ask TTY driver for log output */
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mess.GETKM_GRANT= gid;
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mess.m_type = GET_KMESS_S;
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r= sendrec(TTY_PROC_NR, &mess);
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cpf_revoke(gid);
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if (r == OK) r= mess.m_type;
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if (r != OK)
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{
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report("LOG","couldn't get copy of kmessages from TTY", r);
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return EDONTREPLY;
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}
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}
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else
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{
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/* Try to get a fresh copy of the buffer with kernel messages. */
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if ((r=sys_getkmessages(&kmess)) != OK) {
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report("LOG","couldn't get copy of kmessages", r);
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return EDONTREPLY;
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}
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prev_nextp= &kernel_prev_next;
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}
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/* Print only the new part. Determine how many new bytes there are with
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* help of the current and previous 'next' index. Note that the kernel
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* buffer is circular. This works fine if less then KMESS_BUF_SIZE bytes
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* is new data; else we miss % KMESS_BUF_SIZE here.
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* Check for size being positive, the buffer might as well be emptied!
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*/
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if (kmess.km_size > 0) {
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bytes = ((kmess.km_next + _KMESS_BUF_SIZE) - (*prev_nextp)) %
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_KMESS_BUF_SIZE;
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r= *prev_nextp; /* start at previous old */
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i=0;
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while (bytes > 0) {
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print_buf[i] = kmess.km_buf[(r%_KMESS_BUF_SIZE)];
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bytes --;
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r ++;
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i ++;
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}
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/* Now terminate the new message and save it in the log. */
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print_buf[i] = 0;
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log_append(print_buf, i);
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}
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/* Almost done, store 'next' so that we can determine what part of the
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* kernel messages buffer to print next time a notification arrives.
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*/
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*prev_nextp = kmess.km_next;
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return EDONTREPLY;
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}
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/*===========================================================================*
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* do_diagnostics *
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*===========================================================================*/
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PUBLIC int do_diagnostics(message *m, int safe)
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{
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/* The LOG server handles all diagnostic messages from servers and device
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* drivers. It forwards the message to the TTY driver to display it to the
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* user. It also saves a copy in a local buffer so that messages can be
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* reviewed at a later time.
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*/
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vir_bytes src;
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int count;
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char c;
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int i = 0, offset = 0;
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static char diagbuf[10240];
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/* Also make a copy for the private buffer at the LOG server, so
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* that the messages can be reviewed at a later time.
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*/
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src = (vir_bytes) m->DIAG_PRINT_BUF_G;
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count = m->DIAG_BUF_COUNT;
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while (count > 0 && i < sizeof(diagbuf)-1) {
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int r;
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if(safe) {
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r = sys_safecopyfrom(m->m_source, src, offset, (vir_bytes) &c, 1, D);
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} else {
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r = sys_datacopy(m->m_source, src+offset, SELF, (vir_bytes) &c, 1);
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}
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if(r != OK) break;
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offset ++;
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count --;
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diagbuf[i++] = c;
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}
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log_append(diagbuf, i);
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if(m->m_type == ASYN_DIAGNOSTICS_OLD) return EDONTREPLY;
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return OK;
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}
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