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freebsd-skq/sys/kern/sys_process.c
tanimura a09da29859 Lock struct pgrp, session and sigio. 
New locks are:

- pgrpsess_lock which locks the whole pgrps and sessions,
- pg_mtx which protects the pgrp members, and
- s_mtx which protects the session members.

Please refer to sys/proc.h for the coverage of these locks.

Changes on the pgrp/session interface:

- pgfind() needs the pgrpsess_lock held.

- The caller of enterpgrp() is responsible to allocate a new pgrp and
  session.

- Call enterthispgrp() in order to enter an existing pgrp.

- pgsignal() requires a pgrp lock held.

Reviewed by:	jhb, alfred
Tested on:	cvsup.jp.FreeBSD.org
		(which is a quad-CPU machine running -current)
2002-02-23 11:12:57 +00:00

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/*
* Copyright (c) 1994, Sean Eric Fagan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Sean Eric Fagan.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/ptrace.h>
#include <sys/sx.h>
#include <sys/user.h>
#include <machine/reg.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
/*
* Functions implemented using PROC_ACTION():
*
* proc_read_regs(proc, regs)
* Get the current user-visible register set from the process
* and copy it into the regs structure (<machine/reg.h>).
* The process is stopped at the time read_regs is called.
*
* proc_write_regs(proc, regs)
* Update the current register set from the passed in regs
* structure. Take care to avoid clobbering special CPU
* registers or privileged bits in the PSL.
* Depending on the architecture this may have fix-up work to do,
* especially if the IAR or PCW are modified.
* The process is stopped at the time write_regs is called.
*
* proc_read_fpregs, proc_write_fpregs
* deal with the floating point register set, otherwise as above.
*
* proc_read_dbregs, proc_write_dbregs
* deal with the processor debug register set, otherwise as above.
*
* proc_sstep(proc)
* Arrange for the process to trap after executing a single instruction.
*/
#define PROC_ACTION(action) do { \
int error; \
\
mtx_lock_spin(&sched_lock); \
if ((td->td_proc->p_sflag & PS_INMEM) == 0) \
error = EIO; \
else \
error = (action); \
mtx_unlock_spin(&sched_lock); \
return (error); \
} while(0)
int
proc_read_regs(struct thread *td, struct reg *regs)
{
PROC_ACTION(fill_regs(td, regs));
}
int
proc_write_regs(struct thread *td, struct reg *regs)
{
PROC_ACTION(set_regs(td, regs));
}
int
proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
{
PROC_ACTION(fill_dbregs(td, dbregs));
}
int
proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
{
PROC_ACTION(set_dbregs(td, dbregs));
}
/*
* Ptrace doesn't support fpregs at all, and there are no security holes
* or translations for fpregs, so we can just copy them.
*/
int
proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
{
PROC_ACTION(fill_fpregs(td, fpregs));
}
int
proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
{
PROC_ACTION(set_fpregs(td, fpregs));
}
int
proc_sstep(struct thread *td)
{
PROC_ACTION(ptrace_single_step(td));
}
int
proc_rwmem(struct proc *p, struct uio *uio)
{
struct vmspace *vm;
vm_map_t map;
vm_object_t object = NULL;
vm_offset_t pageno = 0; /* page number */
vm_prot_t reqprot;
vm_offset_t kva;
int error, writing;
GIANT_REQUIRED;
/*
* if the vmspace is in the midst of being deallocated or the
* process is exiting, don't try to grab anything. The page table
* usage in that process can be messed up.
*/
vm = p->p_vmspace;
if ((p->p_flag & P_WEXIT))
return (EFAULT);
if (vm->vm_refcnt < 1)
return (EFAULT);
++vm->vm_refcnt;
/*
* The map we want...
*/
map = &vm->vm_map;
writing = uio->uio_rw == UIO_WRITE;
reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) :
VM_PROT_READ;
kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE);
/*
* Only map in one page at a time. We don't have to, but it
* makes things easier. This way is trivial - right?
*/
do {
vm_map_t tmap;
vm_offset_t uva;
int page_offset; /* offset into page */
vm_map_entry_t out_entry;
vm_prot_t out_prot;
boolean_t wired;
vm_pindex_t pindex;
u_int len;
vm_page_t m;
object = NULL;
uva = (vm_offset_t)uio->uio_offset;
/*
* Get the page number of this segment.
*/
pageno = trunc_page(uva);
page_offset = uva - pageno;
/*
* How many bytes to copy
*/
len = min(PAGE_SIZE - page_offset, uio->uio_resid);
/*
* Fault the page on behalf of the process
*/
error = vm_fault(map, pageno, reqprot, VM_FAULT_NORMAL);
if (error) {
error = EFAULT;
break;
}
/*
* Now we need to get the page. out_entry, out_prot, wired,
* and single_use aren't used. One would think the vm code
* would be a *bit* nicer... We use tmap because
* vm_map_lookup() can change the map argument.
*/
tmap = map;
error = vm_map_lookup(&tmap, pageno, reqprot, &out_entry,
&object, &pindex, &out_prot, &wired);
if (error) {
error = EFAULT;
/*
* Make sure that there is no residue in 'object' from
* an error return on vm_map_lookup.
*/
object = NULL;
break;
}
m = vm_page_lookup(object, pindex);
/* Allow fallback to backing objects if we are reading */
while (m == NULL && !writing && object->backing_object) {
pindex += OFF_TO_IDX(object->backing_object_offset);
object = object->backing_object;
m = vm_page_lookup(object, pindex);
}
if (m == NULL) {
error = EFAULT;
/*
* Make sure that there is no residue in 'object' from
* an error return on vm_map_lookup.
*/
object = NULL;
vm_map_lookup_done(tmap, out_entry);
break;
}
/*
* Wire the page into memory
*/
vm_page_wire(m);
/*
* We're done with tmap now.
* But reference the object first, so that we won't loose
* it.
*/
vm_object_reference(object);
vm_map_lookup_done(tmap, out_entry);
pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
/*
* Now do the i/o move.
*/
error = uiomove((caddr_t)(kva + page_offset), len, uio);
pmap_kremove(kva);
/*
* release the page and the object
*/
vm_page_unwire(m, 1);
vm_object_deallocate(object);
object = NULL;
} while (error == 0 && uio->uio_resid > 0);
if (object)
vm_object_deallocate(object);
kmem_free(kernel_map, kva, PAGE_SIZE);
vmspace_free(vm);
return (error);
}
/*
* Process debugging system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct ptrace_args {
int req;
pid_t pid;
caddr_t addr;
int data;
};
#endif
int
ptrace(struct thread *td, struct ptrace_args *uap)
{
struct iovec iov;
struct uio uio;
/*
* XXX this obfuscation is to reduce stack usage, but the register
* structs may be too large to put on the stack anyway.
*/
union {
struct dbreg dbreg;
struct fpreg fpreg;
struct reg reg;
} r;
struct proc *curp, *p;
struct thread *td2;
int error, write;
curp = td->td_proc;
error = 0;
write = 0;
if (uap->req == PT_TRACE_ME) {
p = curp;
PROC_LOCK(p);
} else {
if ((p = pfind(uap->pid)) == NULL)
return (ESRCH);
}
if (p_cansee(curp, p)) {
PROC_UNLOCK(p);
return (ESRCH);
}
if ((error = p_candebug(curp, p)) != 0) {
PROC_UNLOCK(p);
return (error);
}
/*
* System processes can't be debugged.
*/
if ((p->p_flag & P_SYSTEM) != 0) {
PROC_UNLOCK(p);
return (EINVAL);
}
/*
* Permissions check
*/
switch (uap->req) {
case PT_TRACE_ME:
/* Always legal. */
break;
case PT_ATTACH:
/* Self */
if (p->p_pid == curp->p_pid) {
PROC_UNLOCK(p);
return (EINVAL);
}
/* Already traced */
if (p->p_flag & P_TRACED) {
PROC_UNLOCK(p);
return (EBUSY);
}
/* OK */
break;
case PT_READ_I:
case PT_READ_D:
case PT_WRITE_I:
case PT_WRITE_D:
case PT_CONTINUE:
case PT_KILL:
case PT_STEP:
case PT_DETACH:
#ifdef PT_GETREGS
case PT_GETREGS:
#endif
#ifdef PT_SETREGS
case PT_SETREGS:
#endif
#ifdef PT_GETFPREGS
case PT_GETFPREGS:
#endif
#ifdef PT_SETFPREGS
case PT_SETFPREGS:
#endif
#ifdef PT_GETDBREGS
case PT_GETDBREGS:
#endif
#ifdef PT_SETDBREGS
case PT_SETDBREGS:
#endif
/* not being traced... */
if ((p->p_flag & P_TRACED) == 0) {
PROC_UNLOCK(p);
return (EPERM);
}
/* not being traced by YOU */
if (p->p_pptr != curp) {
PROC_UNLOCK(p);
return (EBUSY);
}
/* not currently stopped */
mtx_lock_spin(&sched_lock);
if (p->p_stat != SSTOP || (p->p_flag & P_WAITED) == 0) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
return (EBUSY);
}
mtx_unlock_spin(&sched_lock);
/* OK */
break;
default:
PROC_UNLOCK(p);
return (EINVAL);
}
td2 = FIRST_THREAD_IN_PROC(p);
PROC_UNLOCK(p);
#ifdef FIX_SSTEP
/*
* Single step fixup ala procfs
*/
FIX_SSTEP(td2); /* XXXKSE */
#endif
/*
* Actually do the requests
*/
td->td_retval[0] = 0;
switch (uap->req) {
case PT_TRACE_ME:
/* set my trace flag and "owner" so it can read/write me */
sx_xlock(&proctree_lock);
PROC_LOCK(p);
p->p_flag |= P_TRACED;
p->p_oppid = p->p_pptr->p_pid;
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
return (0);
case PT_ATTACH:
/* security check done above */
sx_xlock(&proctree_lock);
PROC_LOCK(p);
p->p_flag |= P_TRACED;
p->p_oppid = p->p_pptr->p_pid;
if (p->p_pptr != curp)
proc_reparent(p, curp);
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
uap->data = SIGSTOP;
goto sendsig; /* in PT_CONTINUE below */
case PT_STEP:
case PT_CONTINUE:
case PT_DETACH:
/* XXX uap->data is used even in the PT_STEP case. */
if (uap->req != PT_STEP && (unsigned)uap->data >= NSIG)
return (EINVAL);
PHOLD(p);
if (uap->req == PT_STEP) {
error = ptrace_single_step(td2);
if (error) {
PRELE(p);
return (error);
}
}
if (uap->addr != (caddr_t)1) {
fill_kinfo_proc(p, &p->p_uarea->u_kproc);
error = ptrace_set_pc(td2,
(u_long)(uintfptr_t)uap->addr);
if (error) {
PRELE(p);
return (error);
}
}
PRELE(p);
if (uap->req == PT_DETACH) {
/* reset process parent */
sx_xlock(&proctree_lock);
if (p->p_oppid != p->p_pptr->p_pid) {
struct proc *pp;
pp = pfind(p->p_oppid);
if (pp == NULL)
pp = initproc;
else
PROC_UNLOCK(pp);
PROC_LOCK(p);
proc_reparent(p, pp);
} else
PROC_LOCK(p);
p->p_flag &= ~(P_TRACED | P_WAITED);
p->p_oppid = 0;
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
/* should we send SIGCHLD? */
}
sendsig:
/* deliver or queue signal */
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
if (p->p_stat == SSTOP) {
p->p_xstat = uap->data;
setrunnable(td2); /* XXXKSE */
mtx_unlock_spin(&sched_lock);
} else {
mtx_unlock_spin(&sched_lock);
if (uap->data)
psignal(p, uap->data);
}
PROC_UNLOCK(p);
return (0);
case PT_WRITE_I:
case PT_WRITE_D:
write = 1;
/* fallthrough */
case PT_READ_I:
case PT_READ_D:
/* write = 0 set above */
iov.iov_base = write ? (caddr_t)&uap->data :
(caddr_t)td->td_retval;
iov.iov_len = sizeof(int);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = (off_t)(uintptr_t)uap->addr;
uio.uio_resid = sizeof(int);
uio.uio_segflg = UIO_SYSSPACE; /* i.e.: the uap */
uio.uio_rw = write ? UIO_WRITE : UIO_READ;
uio.uio_td = td;
error = proc_rwmem(p, &uio);
if (uio.uio_resid != 0) {
/*
* XXX proc_rwmem() doesn't currently return ENOSPC,
* so I think write() can bogusly return 0.
* XXX what happens for short writes? We don't want
* to write partial data.
* XXX proc_rwmem() returns EPERM for other invalid
* addresses. Convert this to EINVAL. Does this
* clobber returns of EPERM for other reasons?
*/
if (error == 0 || error == ENOSPC || error == EPERM)
error = EINVAL; /* EOF */
}
return (error);
case PT_KILL:
uap->data = SIGKILL;
goto sendsig; /* in PT_CONTINUE above */
#ifdef PT_SETREGS
case PT_SETREGS:
error = copyin(uap->addr, &r.reg, sizeof r.reg);
if (error == 0) {
PHOLD(p);
error = proc_write_regs(td2, &r.reg);
PRELE(p);
}
return (error);
#endif /* PT_SETREGS */
#ifdef PT_GETREGS
case PT_GETREGS:
PHOLD(p);
error = proc_read_regs(td2, &r.reg);
PRELE(p);
if (error == 0)
error = copyout(&r.reg, uap->addr, sizeof r.reg);
return (error);
#endif /* PT_SETREGS */
#ifdef PT_SETFPREGS
case PT_SETFPREGS:
error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg);
if (error == 0) {
PHOLD(p);
error = proc_write_fpregs(td2, &r.fpreg);
PRELE(p);
}
return (error);
#endif /* PT_SETFPREGS */
#ifdef PT_GETFPREGS
case PT_GETFPREGS:
PHOLD(p);
error = proc_read_fpregs(td2, &r.fpreg);
PRELE(p);
if (error == 0)
error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg);
return (error);
#endif /* PT_SETFPREGS */
#ifdef PT_SETDBREGS
case PT_SETDBREGS:
error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg);
if (error == 0) {
PHOLD(p);
error = proc_write_dbregs(td2, &r.dbreg);
PRELE(p);
}
return (error);
#endif /* PT_SETDBREGS */
#ifdef PT_GETDBREGS
case PT_GETDBREGS:
PHOLD(p);
error = proc_read_dbregs(td2, &r.dbreg);
PRELE(p);
if (error == 0)
error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg);
return (error);
#endif /* PT_SETDBREGS */
default:
KASSERT(0, ("unreachable code\n"));
break;
}
KASSERT(0, ("unreachable code\n"));
return (0);
}
int
trace_req(struct proc *p)
{
return (1);
}
/*
* Stop a process because of a debugging event;
* stay stopped until p->p_step is cleared
* (cleared by PIOCCONT in procfs).
*/
void
stopevent(struct proc *p, unsigned int event, unsigned int val)
{
PROC_LOCK_ASSERT(p, MA_OWNED | MA_NOTRECURSED);
p->p_step = 1;
do {
p->p_xstat = val;
p->p_stype = event; /* Which event caused the stop? */
wakeup(&p->p_stype); /* Wake up any PIOCWAIT'ing procs */
msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
} while (p->p_step);
}
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