minix/drivers/log/diag.c
David van Moolenbroek b423d7b477 Merge of David's ptrace branch. Summary:
o Support for ptrace T_ATTACH/T_DETACH and T_SYSCALL
o PM signal handling logic should now work properly, even with debuggers
  being present
o Asynchronous PM/VFS protocol, full IPC support for senda(), and
  AMF_NOREPLY senda() flag

DETAILS

Process stop and delay call handling of PM:
o Added sys_runctl() kernel call with sys_stop() and sys_resume()
  aliases, for PM to stop and resume a process
o Added exception for sending/syscall-traced processes to sys_runctl(),
  and matching SIGKREADY pseudo-signal to PM
o Fixed PM signal logic to deal with requests from a process after
  stopping it (so-called "delay calls"), using the SIGKREADY facility
o Fixed various PM panics due to race conditions with delay calls versus
  VFS calls
o Removed special PRIO_STOP priority value
o Added SYS_LOCK RTS kernel flag, to stop an individual process from
  running while modifying its process structure

Signal and debugger handling in PM:
o Fixed debugger signals being dropped if a second signal arrives when
  the debugger has not retrieved the first one
o Fixed debugger signals being sent to the debugger more than once
o Fixed debugger signals unpausing process in VFS; removed PM_UNPAUSE_TR
  protocol message
o Detached debugger signals from general signal logic and from being
  blocked on VFS calls, meaning that even VFS can now be traced
o Fixed debugger being unable to receive more than one pending signal in
  one process stop
o Fixed signal delivery being delayed needlessly when multiple signals
  are pending
o Fixed wait test for tracer, which was returning for children that were
  not waited for
o Removed second parallel pending call from PM to VFS for any process
o Fixed process becoming runnable between exec() and debugger trap
o Added support for notifying the debugger before the parent when a
  debugged child exits
o Fixed debugger death causing child to remain stopped forever
o Fixed consistently incorrect use of _NSIG

Extensions to ptrace():
o Added T_ATTACH and T_DETACH ptrace request, to attach and detach a
  debugger to and from a process
o Added T_SYSCALL ptrace request, to trace system calls
o Added T_SETOPT ptrace request, to set trace options
o Added TO_TRACEFORK trace option, to attach automatically to children
  of a traced process
o Added TO_ALTEXEC trace option, to send SIGSTOP instead of SIGTRAP upon
  a successful exec() of the tracee
o Extended T_GETUSER ptrace support to allow retrieving a process's priv
  structure
o Removed T_STOP ptrace request again, as it does not help implementing
  debuggers properly
o Added MINIX3-specific ptrace test (test42)
o Added proper manual page for ptrace(2)

Asynchronous PM/VFS interface:
o Fixed asynchronous messages not being checked when receive() is called
  with an endpoint other than ANY
o Added AMF_NOREPLY senda() flag, preventing such messages from
  satisfying the receive part of a sendrec()
o Added asynsend3() that takes optional flags; asynsend() is now a
  #define passing in 0 as third parameter
o Made PM/VFS protocol asynchronous; reintroduced tell_fs()
o Made PM_BASE request/reply number range unique
o Hacked in a horrible temporary workaround into RS to deal with newly
  revealed RS-PM-VFS race condition triangle until VFS is asynchronous

System signal handling:
o Fixed shutdown logic of device drivers; removed old SIGKSTOP signal
o Removed is-superuser check from PM's do_procstat() (aka getsigset())
o Added sigset macros to allow system processes to deal with the full
  signal set, rather than just the POSIX subset

Miscellaneous PM fixes:
o Split do_getset into do_get and do_set, merging common code and making
  structure clearer
o Fixed setpriority() being able to put to sleep processes using an
  invalid parameter, or revive zombie processes
o Made find_proc() global; removed obsolete proc_from_pid()
o Cleanup here and there

Also included:
o Fixed false-positive boot order kernel warning
o Removed last traces of old NOTIFY_FROM code

THINGS OF POSSIBLE INTEREST

o It should now be possible to run PM at any priority, even lower than
  user processes
o No assumptions are made about communication speed between PM and VFS,
  although communication must be FIFO
o A debugger will now receive incoming debuggee signals at kill time
  only; the process may not yet be fully stopped
o A first step has been made towards making the SYSTEM task preemptible
2009-09-30 09:57:22 +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(from)
endpoint_t from; /* who sent this 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 (from == 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;
}