minix/kernel/debug.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

149 lines
3.6 KiB
C

/* This file implements kernel debugging functionality that is not included
* in the standard kernel. Available functionality includes timing of lock
* functions and sanity checking of the scheduling queues.
*/
#include "kernel.h"
#include "proc.h"
#include "debug.h"
#include <minix/sysutil.h>
#include <limits.h>
#include <string.h>
#if DEBUG_SCHED_CHECK /* only include code if enabled */
#define MAX_LOOP (NR_PROCS + NR_TASKS)
PUBLIC void
check_runqueues_f(char *file, int line)
{
int q, l = 0;
register struct proc *xp;
if(!intr_disabled()) {
minix_panic("check_runqueues called with interrupts enabled", NO_NUM);
}
FIXME("check_runqueues being done");
#define MYPANIC(msg) { \
kprintf("check_runqueues:%s:%d: %s\n", file, line, msg); \
minix_panic("check_runqueues failed", NO_NUM); \
}
for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
xp->p_found = 0;
if (l++ > MAX_LOOP) { MYPANIC("check error"); }
}
for (q=l=0; q < NR_SCHED_QUEUES; q++) {
if (rdy_head[q] && !rdy_tail[q]) {
kprintf("head but no tail in %d\n", q);
MYPANIC("scheduling error");
}
if (!rdy_head[q] && rdy_tail[q]) {
kprintf("tail but no head in %d\n", q);
MYPANIC("scheduling error");
}
if (rdy_tail[q] && rdy_tail[q]->p_nextready != NIL_PROC) {
kprintf("tail and tail->next not null in %d\n", q);
MYPANIC("scheduling error");
}
for(xp = rdy_head[q]; xp != NIL_PROC; xp = xp->p_nextready) {
vir_bytes vxp = (vir_bytes) xp, dxp;
if(vxp < (vir_bytes) BEG_PROC_ADDR || vxp >= (vir_bytes) END_PROC_ADDR) {
MYPANIC("xp out of range");
}
dxp = vxp - (vir_bytes) BEG_PROC_ADDR;
if(dxp % sizeof(struct proc)) {
MYPANIC("xp not a real pointer");
}
if(xp->p_magic != PMAGIC) {
MYPANIC("magic wrong in xp");
}
if (RTS_ISSET(xp, SLOT_FREE)) {
kprintf("scheduling error: dead proc q %d %d\n",
q, xp->p_endpoint);
MYPANIC("dead proc on run queue");
}
if (!xp->p_ready) {
kprintf("scheduling error: unready on runq %d proc %d\n",
q, xp->p_nr);
MYPANIC("found unready process on run queue");
}
if (xp->p_priority != q) {
kprintf("scheduling error: wrong priority q %d proc %d ep %d name %s\n",
q, xp->p_nr, xp->p_endpoint, xp->p_name);
MYPANIC("wrong priority");
}
if (xp->p_found) {
kprintf("scheduling error: double sched q %d proc %d\n",
q, xp->p_nr);
MYPANIC("proc more than once on scheduling queue");
}
xp->p_found = 1;
if (xp->p_nextready == NIL_PROC && rdy_tail[q] != xp) {
kprintf("sched err: last element not tail q %d proc %d\n",
q, xp->p_nr);
MYPANIC("scheduling error");
}
if (l++ > MAX_LOOP) MYPANIC("loop in schedule queue?");
}
}
l = 0;
for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
if(xp->p_magic != PMAGIC)
MYPANIC("p_magic wrong in proc table");
if (isemptyp(xp))
continue;
if(xp->p_ready && ! xp->p_found) {
kprintf("sched error: ready proc %d not on queue\n", xp->p_nr);
MYPANIC("ready proc not on scheduling queue");
if (l++ > MAX_LOOP) { MYPANIC("loop in debug.c?"); }
}
}
}
#endif /* DEBUG_SCHED_CHECK */
PUBLIC char *
rtsflagstr(int flags)
{
static char str[100];
str[0] = '\0';
#define FLAG(n) if(flags & n) { strcat(str, #n " "); }
FLAG(SLOT_FREE);
FLAG(PROC_STOP);
FLAG(SENDING);
FLAG(RECEIVING);
FLAG(SIGNALED);
FLAG(SIG_PENDING);
FLAG(P_STOP);
FLAG(NO_PRIV);
FLAG(NO_ENDPOINT);
FLAG(VMINHIBIT);
FLAG(PAGEFAULT);
FLAG(VMREQUEST);
FLAG(VMREQTARGET);
return str;
}
PUBLIC char *
miscflagstr(int flags)
{
static char str[100];
str[0] = '\0';
FLAG(MF_REPLY_PEND);
FLAG(MF_ASYNMSG);
FLAG(MF_FULLVM);
FLAG(MF_DELIVERMSG);
return str;
}