minix/drivers/log/diag.c
Ben Gras 3cc092ff06 . new kernel call sysctl for generic unprivileged system operations;
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.
2009-01-26 17:43:59 +00:00

140 lines
4 KiB
C

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