minix/drivers/log/diag.c

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/* 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 *
*==========================================================================*/
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
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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;
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
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if (from == TTY_PROC_NR)
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{
cp_grant_id_t gid;
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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;
}
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/* Ask TTY driver for log output */
mess.GETKM_GRANT= gid;
mess.m_type = GET_KMESS_S;
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r= sendrec(TTY_PROC_NR, &mess);
cpf_revoke(gid);
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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;
}