minix/servers/pm/getset.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

120 lines
2.9 KiB
C

/* This file handles the 6 system calls that get and set uids and gids.
* It also handles getpid(), setsid(), and getpgrp(). The code for each
* one is so tiny that it hardly seemed worthwhile to make each a separate
* function.
*/
#include "pm.h"
#include <minix/callnr.h>
#include <minix/endpoint.h>
#include <minix/com.h>
#include <signal.h>
#include "mproc.h"
#include "param.h"
/*===========================================================================*
* do_get *
*===========================================================================*/
PUBLIC int do_get()
{
/* Handle GETUID, GETGID, GETPID, GETPGRP.
*/
register struct mproc *rmp = mp;
int r, proc;
switch(call_nr) {
case GETUID:
r = rmp->mp_realuid;
rmp->mp_reply.reply_res2 = rmp->mp_effuid;
if (pm_isokendpt(m_in.PM_ENDPT, &proc) == OK && proc >= 0)
rmp->mp_reply.reply_res3 = mproc[proc].mp_effuid;
break;
case GETGID:
r = rmp->mp_realgid;
rmp->mp_reply.reply_res2 = rmp->mp_effgid;
if (pm_isokendpt(m_in.PM_ENDPT, &proc) == OK && proc >= 0)
rmp->mp_reply.reply_res3 = mproc[proc].mp_effgid;
break;
case MINIX_GETPID:
r = mproc[who_p].mp_pid;
rmp->mp_reply.reply_res2 = mproc[rmp->mp_parent].mp_pid;
if(pm_isokendpt(m_in.PM_ENDPT, &proc) == OK && proc >= 0)
rmp->mp_reply.reply_res3 = mproc[proc].mp_pid;
break;
case GETPGRP:
r = rmp->mp_procgrp;
break;
default:
r = EINVAL;
break;
}
return(r);
}
/*===========================================================================*
* do_set *
*===========================================================================*/
PUBLIC int do_set()
{
/* Handle SETUID, SETEUID, SETGID, SETEGID, SETSID. These calls have in common
* that, if successful, they will be forwarded to VFS as well.
*/
register struct mproc *rmp = mp;
message m;
int r;
switch(call_nr) {
case SETUID:
case SETEUID:
if (rmp->mp_realuid != (uid_t) m_in.usr_id &&
rmp->mp_effuid != SUPER_USER)
return(EPERM);
if(call_nr == SETUID) rmp->mp_realuid = (uid_t) m_in.usr_id;
rmp->mp_effuid = (uid_t) m_in.usr_id;
m.m_type = PM_SETUID;
m.PM_PROC = rmp->mp_endpoint;
m.PM_EID = rmp->mp_effuid;
m.PM_RID = rmp->mp_realuid;
break;
case SETGID:
case SETEGID:
if (rmp->mp_realgid != (gid_t) m_in.grp_id &&
rmp->mp_effuid != SUPER_USER)
return(EPERM);
if(call_nr == SETGID) rmp->mp_realgid = (gid_t) m_in.grp_id;
rmp->mp_effgid = (gid_t) m_in.grp_id;
m.m_type = PM_SETGID;
m.PM_PROC = rmp->mp_endpoint;
m.PM_EID = rmp->mp_effgid;
m.PM_RID = rmp->mp_realgid;
break;
case SETSID:
if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
rmp->mp_procgrp = rmp->mp_pid;
m.m_type = PM_SETSID;
m.PM_PROC = rmp->mp_endpoint;
break;
default:
return(EINVAL);
}
/* Send the request to FS */
tell_fs(rmp, &m);
/* Do not reply until FS has processed the request */
return(SUSPEND);
}