minix/servers/pm/utility.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

159 lines
4.3 KiB
C

/* This file contains some utility routines for PM.
*
* The entry points are:
* get_free_pid: get a free process or group id
* no_sys: called for invalid system call numbers
* find_param: look up a boot monitor parameter
* find_proc: return process pointer from pid number
* pm_isokendpt: check the validity of an endpoint
* tell_fs: send a request to FS on behalf of a process
*/
#include "pm.h"
#include <sys/stat.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/endpoint.h>
#include <fcntl.h>
#include <signal.h> /* needed only because mproc.h needs it */
#include "mproc.h"
#include "param.h"
#include <minix/config.h>
#include <timers.h>
#include <string.h>
#include <archconst.h>
#include <archtypes.h>
#include "../../kernel/const.h"
#include "../../kernel/config.h"
#include "../../kernel/type.h"
#include "../../kernel/proc.h"
#define munmap _munmap
#define munmap_text _munmap_text
#include <sys/mman.h>
#undef munmap
#undef munmap_text
/*===========================================================================*
* get_free_pid *
*===========================================================================*/
PUBLIC pid_t get_free_pid()
{
static pid_t next_pid = INIT_PID + 1; /* next pid to be assigned */
register struct mproc *rmp; /* check process table */
int t; /* zero if pid still free */
/* Find a free pid for the child and put it in the table. */
do {
t = 0;
next_pid = (next_pid < NR_PIDS ? next_pid + 1 : INIT_PID + 1);
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++)
if (rmp->mp_pid == next_pid || rmp->mp_procgrp == next_pid) {
t = 1;
break;
}
} while (t); /* 't' = 0 means pid free */
return(next_pid);
}
/*===========================================================================*
* no_sys *
*===========================================================================*/
PUBLIC int no_sys()
{
/* A system call number not implemented by PM has been requested. */
printf("PM: in no_sys, call nr %d from %d\n", call_nr, who_e);
return(ENOSYS);
}
/*===========================================================================*
* find_param *
*===========================================================================*/
PUBLIC char *find_param(name)
const char *name;
{
register const char *namep;
register char *envp;
for (envp = (char *) monitor_params; *envp != 0;) {
for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
;
if (*namep == '\0' && *envp == '=')
return(envp + 1);
while (*envp++ != 0)
;
}
return(NULL);
}
/*===========================================================================*
* find_proc *
*===========================================================================*/
PUBLIC struct mproc *find_proc(lpid)
pid_t lpid;
{
register struct mproc *rmp;
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++)
if ((rmp->mp_flags & IN_USE) && rmp->mp_pid == lpid)
return(rmp);
return(NIL_MPROC);
}
/*===========================================================================*
* pm_isokendpt *
*===========================================================================*/
PUBLIC int pm_isokendpt(int endpoint, int *proc)
{
*proc = _ENDPOINT_P(endpoint);
if(*proc < -NR_TASKS || *proc >= NR_PROCS)
return EINVAL;
if(*proc >= 0 && endpoint != mproc[*proc].mp_endpoint)
return EDEADSRCDST;
if(*proc >= 0 && !(mproc[*proc].mp_flags & IN_USE))
return EDEADSRCDST;
return OK;
}
/*===========================================================================*
* tell_fs *
*===========================================================================*/
PUBLIC void tell_fs(rmp, m_ptr)
struct mproc *rmp;
message *m_ptr;
{
/* Send a request to VFS, without blocking.
*/
int r;
if (rmp->mp_flags & FS_CALL)
panic(__FILE__, "tell_fs: not idle", m_ptr->m_type);
r = asynsend3(FS_PROC_NR, m_ptr, AMF_NOREPLY);
if (r != OK)
panic(__FILE__, "unable to send to FS", r);
rmp->mp_flags |= FS_CALL;
}
int unmap_ok = 0;
PUBLIC int munmap(void *addrstart, vir_bytes len)
{
if(!unmap_ok)
return ENOSYS;
return _munmap(addrstart, len);
}
PUBLIC int munmap_text(void *addrstart, vir_bytes len)
{
if(!unmap_ok)
return ENOSYS;
return _munmap_text(addrstart, len);
}