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006d15596a
freebsd/sys/kern/sys_process.c
Alan Cox acd11c7499 Introduce vm_fault_hold() and use it to (1) eliminate a long-standing race 
condition in proc_rwmem() and to (2) simplify the implementation of the
cxgb driver's vm_fault_hold_user_pages().  Specifically, in proc_rwmem()
the requested read or write could fail because the targeted page could be
reclaimed between the calls to vm_fault() and vm_page_hold().

In collaboration with:	kib@
MFC after:	6 weeks
2010-12-20 22:49:31 +00:00

1216 lines
27 KiB
C
Raw Blame History

/*-
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/ptrace.h>
#include <sys/sx.h>
#include <sys/malloc.h>
#include <sys/signalvar.h>
#include <machine/reg.h>
#include <security/audit/audit.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>
#include <vm/vm_pager.h>
#include <vm/vm_param.h>
#ifdef COMPAT_FREEBSD32
#include <sys/procfs.h>
#include <compat/freebsd32/freebsd32_signal.h>
struct ptrace_io_desc32 {
int piod_op;
uint32_t piod_offs;
uint32_t piod_addr;
uint32_t piod_len;
};
struct ptrace_vm_entry32 {
int pve_entry;
int pve_timestamp;
uint32_t pve_start;
uint32_t pve_end;
uint32_t pve_offset;
u_int pve_prot;
u_int pve_pathlen;
int32_t pve_fileid;
u_int pve_fsid;
uint32_t pve_path;
};
struct ptrace_lwpinfo32 {
lwpid_t pl_lwpid; /* LWP described. */
int pl_event; /* Event that stopped the LWP. */
int pl_flags; /* LWP flags. */
sigset_t pl_sigmask; /* LWP signal mask */
sigset_t pl_siglist; /* LWP pending signal */
struct siginfo32 pl_siginfo; /* siginfo for signal */
char pl_tdname[MAXCOMLEN + 1]; /* LWP name. */
};
#endif
/*
* 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; \
\
PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); \
if ((td->td_proc->p_flag & P_INMEM) == 0) \
error = EIO; \
else \
error = (action); \
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));
}
#ifdef COMPAT_FREEBSD32
/* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
int
proc_read_regs32(struct thread *td, struct reg32 *regs32)
{
PROC_ACTION(fill_regs32(td, regs32));
}
int
proc_write_regs32(struct thread *td, struct reg32 *regs32)
{
PROC_ACTION(set_regs32(td, regs32));
}
int
proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
{
PROC_ACTION(fill_dbregs32(td, dbregs32));
}
int
proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
{
PROC_ACTION(set_dbregs32(td, dbregs32));
}
int
proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
{
PROC_ACTION(fill_fpregs32(td, fpregs32));
}
int
proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
{
PROC_ACTION(set_fpregs32(td, fpregs32));
}
#endif
int
proc_sstep(struct thread *td)
{
PROC_ACTION(ptrace_single_step(td));
}
int
proc_rwmem(struct proc *p, struct uio *uio)
{
vm_map_t map;
vm_offset_t pageno; /* page number */
vm_prot_t reqprot;
int error, fault_flags, page_offset, writing;
/*
* Assert that someone has locked this vmspace. (Should be
* curthread but we can't assert that.) This keeps the process
* from exiting out from under us until this operation completes.
*/
KASSERT(p->p_lock >= 1, ("%s: process %p (pid %d) not held", __func__,
p, p->p_pid));
/*
* The map we want...
*/
map = &p->p_vmspace->vm_map;
/*
* If we are writing, then we request vm_fault() to create a private
* copy of each page. Since these copies will not be writeable by the
* process, we must explicity request that they be dirtied.
*/
writing = uio->uio_rw == UIO_WRITE;
reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
/*
* 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_offset_t uva;
u_int len;
vm_page_t m;
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 and hold the page on behalf of the process.
*/
error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
if (error != KERN_SUCCESS) {
if (error == KERN_RESOURCE_SHORTAGE)
error = ENOMEM;
else
error = EFAULT;
break;
}
/*
* Now do the i/o move.
*/
error = uiomove_fromphys(&m, page_offset, len, uio);
/* Make the I-cache coherent for breakpoints. */
if (writing && error == 0) {
vm_map_lock_read(map);
if (vm_map_check_protection(map, pageno, pageno +
PAGE_SIZE, VM_PROT_EXECUTE))
vm_sync_icache(map, uva, len);
vm_map_unlock_read(map);
}
/*
* Release the page.
*/
vm_page_lock(m);
vm_page_unhold(m);
vm_page_unlock(m);
} while (error == 0 && uio->uio_resid > 0);
return (error);
}
static int
ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
{
struct vattr vattr;
vm_map_t map;
vm_map_entry_t entry;
vm_object_t obj, tobj, lobj;
struct vmspace *vm;
struct vnode *vp;
char *freepath, *fullpath;
u_int pathlen;
int error, index, vfslocked;
error = 0;
obj = NULL;
vm = vmspace_acquire_ref(p);
map = &vm->vm_map;
vm_map_lock_read(map);
do {
entry = map->header.next;
index = 0;
while (index < pve->pve_entry && entry != &map->header) {
entry = entry->next;
index++;
}
if (index != pve->pve_entry) {
error = EINVAL;
break;
}
while (entry != &map->header &&
(entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
entry = entry->next;
index++;
}
if (entry == &map->header) {
error = ENOENT;
break;
}
/* We got an entry. */
pve->pve_entry = index + 1;
pve->pve_timestamp = map->timestamp;
pve->pve_start = entry->start;
pve->pve_end = entry->end - 1;
pve->pve_offset = entry->offset;
pve->pve_prot = entry->protection;
/* Backing object's path needed? */
if (pve->pve_pathlen == 0)
break;
pathlen = pve->pve_pathlen;
pve->pve_pathlen = 0;
obj = entry->object.vm_object;
if (obj != NULL)
VM_OBJECT_LOCK(obj);
} while (0);
vm_map_unlock_read(map);
vmspace_free(vm);
pve->pve_fsid = VNOVAL;
pve->pve_fileid = VNOVAL;
if (error == 0 && obj != NULL) {
lobj = obj;
for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
if (tobj != obj)
VM_OBJECT_LOCK(tobj);
if (lobj != obj)
VM_OBJECT_UNLOCK(lobj);
lobj = tobj;
pve->pve_offset += tobj->backing_object_offset;
}
vp = (lobj->type == OBJT_VNODE) ? lobj->handle : NULL;
if (vp != NULL)
vref(vp);
if (lobj != obj)
VM_OBJECT_UNLOCK(lobj);
VM_OBJECT_UNLOCK(obj);
if (vp != NULL) {
freepath = NULL;
fullpath = NULL;
vn_fullpath(td, vp, &fullpath, &freepath);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_SHARED | LK_RETRY);
if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
pve->pve_fileid = vattr.va_fileid;
pve->pve_fsid = vattr.va_fsid;
}
vput(vp);
VFS_UNLOCK_GIANT(vfslocked);
if (fullpath != NULL) {
pve->pve_pathlen = strlen(fullpath) + 1;
if (pve->pve_pathlen <= pathlen) {
error = copyout(fullpath, pve->pve_path,
pve->pve_pathlen);
} else
error = ENAMETOOLONG;
}
if (freepath != NULL)
free(freepath, M_TEMP);
}
}
return (error);
}
#ifdef COMPAT_FREEBSD32
static int
ptrace_vm_entry32(struct thread *td, struct proc *p,
struct ptrace_vm_entry32 *pve32)
{
struct ptrace_vm_entry pve;
int error;
pve.pve_entry = pve32->pve_entry;
pve.pve_pathlen = pve32->pve_pathlen;
pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
error = ptrace_vm_entry(td, p, &pve);
if (error == 0) {
pve32->pve_entry = pve.pve_entry;
pve32->pve_timestamp = pve.pve_timestamp;
pve32->pve_start = pve.pve_start;
pve32->pve_end = pve.pve_end;
pve32->pve_offset = pve.pve_offset;
pve32->pve_prot = pve.pve_prot;
pve32->pve_fileid = pve.pve_fileid;
pve32->pve_fsid = pve.pve_fsid;
}
pve32->pve_pathlen = pve.pve_pathlen;
return (error);
}
static void
ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
struct ptrace_lwpinfo32 *pl32)
{
pl32->pl_lwpid = pl->pl_lwpid;
pl32->pl_event = pl->pl_event;
pl32->pl_flags = pl->pl_flags;
pl32->pl_sigmask = pl->pl_sigmask;
pl32->pl_siglist = pl->pl_siglist;
siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
strcpy(pl32->pl_tdname, pl->pl_tdname);
}
#endif /* COMPAT_FREEBSD32 */
/*
* Process debugging system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct ptrace_args {
int req;
pid_t pid;
caddr_t addr;
int data;
};
#endif
#ifdef COMPAT_FREEBSD32
/*
* This CPP subterfuge is to try and reduce the number of ifdefs in
* the body of the code.
* COPYIN(uap->addr, &r.reg, sizeof r.reg);
* becomes either:
* copyin(uap->addr, &r.reg, sizeof r.reg);
* or
* copyin(uap->addr, &r.reg32, sizeof r.reg32);
* .. except this is done at runtime.
*/
#define COPYIN(u, k, s) wrap32 ? \
copyin(u, k ## 32, s ## 32) : \
copyin(u, k, s)
#define COPYOUT(k, u, s) wrap32 ? \
copyout(k ## 32, u, s ## 32) : \
copyout(k, u, s)
#else
#define COPYIN(u, k, s) copyin(u, k, s)
#define COPYOUT(k, u, s) copyout(k, u, s)
#endif
int
ptrace(struct thread *td, struct ptrace_args *uap)
{
/*
* XXX this obfuscation is to reduce stack usage, but the register
* structs may be too large to put on the stack anyway.
*/
union {
struct ptrace_io_desc piod;
struct ptrace_lwpinfo pl;
struct ptrace_vm_entry pve;
struct dbreg dbreg;
struct fpreg fpreg;
struct reg reg;
#ifdef COMPAT_FREEBSD32
struct dbreg32 dbreg32;
struct fpreg32 fpreg32;
struct reg32 reg32;
struct ptrace_io_desc32 piod32;
struct ptrace_lwpinfo32 pl32;
struct ptrace_vm_entry32 pve32;
#endif
} r;
void *addr;
int error = 0;
#ifdef COMPAT_FREEBSD32
int wrap32 = 0;
if (SV_CURPROC_FLAG(SV_ILP32))
wrap32 = 1;
#endif
AUDIT_ARG_PID(uap->pid);
AUDIT_ARG_CMD(uap->req);
AUDIT_ARG_VALUE(uap->data);
addr = &r;
switch (uap->req) {
case PT_GETREGS:
case PT_GETFPREGS:
case PT_GETDBREGS:
case PT_LWPINFO:
break;
case PT_SETREGS:
error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
break;
case PT_SETFPREGS:
error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
break;
case PT_SETDBREGS:
error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
break;
case PT_IO:
error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
break;
case PT_VM_ENTRY:
error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
break;
default:
addr = uap->addr;
break;
}
if (error)
return (error);
error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
if (error)
return (error);
switch (uap->req) {
case PT_VM_ENTRY:
error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
break;
case PT_IO:
error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
break;
case PT_GETREGS:
error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
break;
case PT_GETFPREGS:
error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
break;
case PT_GETDBREGS:
error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
break;
case PT_LWPINFO:
error = copyout(&r.pl, uap->addr, uap->data);
break;
}
return (error);
}
#undef COPYIN
#undef COPYOUT
#ifdef COMPAT_FREEBSD32
/*
* PROC_READ(regs, td2, addr);
* becomes either:
* proc_read_regs(td2, addr);
* or
* proc_read_regs32(td2, addr);
* .. except this is done at runtime. There is an additional
* complication in that PROC_WRITE disallows 32 bit consumers
* from writing to 64 bit address space targets.
*/
#define PROC_READ(w, t, a) wrap32 ? \
proc_read_ ## w ## 32(t, a) : \
proc_read_ ## w (t, a)
#define PROC_WRITE(w, t, a) wrap32 ? \
(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
proc_write_ ## w (t, a)
#else
#define PROC_READ(w, t, a) proc_read_ ## w (t, a)
#define PROC_WRITE(w, t, a) proc_write_ ## w (t, a)
#endif
int
kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
{
struct iovec iov;
struct uio uio;
struct proc *curp, *p, *pp;
struct thread *td2 = NULL;
struct ptrace_io_desc *piod = NULL;
struct ptrace_lwpinfo *pl;
int error, write, tmp, num;
int proctree_locked = 0;
lwpid_t tid = 0, *buf;
#ifdef COMPAT_FREEBSD32
int wrap32 = 0, safe = 0;
struct ptrace_io_desc32 *piod32 = NULL;
struct ptrace_lwpinfo32 *pl32 = NULL;
struct ptrace_lwpinfo plr;
#endif
curp = td->td_proc;
/* Lock proctree before locking the process. */
switch (req) {
case PT_TRACE_ME:
case PT_ATTACH:
case PT_STEP:
case PT_CONTINUE:
case PT_TO_SCE:
case PT_TO_SCX:
case PT_SYSCALL:
case PT_DETACH:
sx_xlock(&proctree_lock);
proctree_locked = 1;
break;
default:
break;
}
write = 0;
if (req == PT_TRACE_ME) {
p = td->td_proc;
PROC_LOCK(p);
} else {
if (pid <= PID_MAX) {
if ((p = pfind(pid)) == NULL) {
if (proctree_locked)
sx_xunlock(&proctree_lock);
return (ESRCH);
}
} else {
td2 = tdfind(pid, -1);
if (td2 == NULL) {
if (proctree_locked)
sx_xunlock(&proctree_lock);
return (ESRCH);
}
p = td2->td_proc;
tid = pid;
pid = p->p_pid;
}
}
AUDIT_ARG_PROCESS(p);
if ((p->p_flag & P_WEXIT) != 0) {
error = ESRCH;
goto fail;
}
if ((error = p_cansee(td, p)) != 0)
goto fail;
if ((error = p_candebug(td, p)) != 0)
goto fail;
/*
* System processes can't be debugged.
*/
if ((p->p_flag & P_SYSTEM) != 0) {
error = EINVAL;
goto fail;
}
if (tid == 0) {
if ((p->p_flag & P_STOPPED_TRACE) != 0) {
KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
td2 = p->p_xthread;
} else {
td2 = FIRST_THREAD_IN_PROC(p);
}
tid = td2->td_tid;
}
#ifdef COMPAT_FREEBSD32
/*
* Test if we're a 32 bit client and what the target is.
* Set the wrap controls accordingly.
*/
if (SV_CURPROC_FLAG(SV_ILP32)) {
if (td2->td_proc->p_sysent->sv_flags & SV_ILP32)
safe = 1;
wrap32 = 1;
}
#endif
/*
* Permissions check
*/
switch (req) {
case PT_TRACE_ME:
/* Always legal. */
break;
case PT_ATTACH:
/* Self */
if (p->p_pid == td->td_proc->p_pid) {
error = EINVAL;
goto fail;
}
/* Already traced */
if (p->p_flag & P_TRACED) {
error = EBUSY;
goto fail;
}
/* Can't trace an ancestor if you're being traced. */
if (curp->p_flag & P_TRACED) {
for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
if (pp == p) {
error = EINVAL;
goto fail;
}
}
}
/* OK */
break;
case PT_CLEARSTEP:
/* Allow thread to clear single step for itself */
if (td->td_tid == tid)
break;
/* FALLTHROUGH */
default:
/* not being traced... */
if ((p->p_flag & P_TRACED) == 0) {
error = EPERM;
goto fail;
}
/* not being traced by YOU */
if (p->p_pptr != td->td_proc) {
error = EBUSY;
goto fail;
}
/* not currently stopped */
if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
p->p_suspcount != p->p_numthreads ||
(p->p_flag & P_WAITED) == 0) {
error = EBUSY;
goto fail;
}
if ((p->p_flag & P_STOPPED_TRACE) == 0) {
static int count = 0;
if (count++ == 0)
printf("P_STOPPED_TRACE not set.\n");
}
/* OK */
break;
}
/* Keep this process around until we finish this request. */
_PHOLD(p);
#ifdef FIX_SSTEP
/*
* Single step fixup ala procfs
*/
FIX_SSTEP(td2);
#endif
/*
* Actually do the requests
*/
td->td_retval[0] = 0;
switch (req) {
case PT_TRACE_ME:
/* set my trace flag and "owner" so it can read/write me */
p->p_flag |= P_TRACED;
p->p_oppid = p->p_pptr->p_pid;
break;
case PT_ATTACH:
/* security check done above */
p->p_flag |= P_TRACED;
p->p_oppid = p->p_pptr->p_pid;
if (p->p_pptr != td->td_proc)
proc_reparent(p, td->td_proc);
data = SIGSTOP;
goto sendsig; /* in PT_CONTINUE below */
case PT_CLEARSTEP:
error = ptrace_clear_single_step(td2);
break;
case PT_SETSTEP:
error = ptrace_single_step(td2);
break;
case PT_SUSPEND:
td2->td_dbgflags |= TDB_SUSPEND;
thread_lock(td2);
td2->td_flags |= TDF_NEEDSUSPCHK;
thread_unlock(td2);
break;
case PT_RESUME:
td2->td_dbgflags &= ~TDB_SUSPEND;
break;
case PT_STEP:
case PT_CONTINUE:
case PT_TO_SCE:
case PT_TO_SCX:
case PT_SYSCALL:
case PT_DETACH:
/* Zero means do not send any signal */
if (data < 0 || data > _SIG_MAXSIG) {
error = EINVAL;
break;
}
switch (req) {
case PT_STEP:
error = ptrace_single_step(td2);
if (error)
goto out;
break;
case PT_CONTINUE:
case PT_TO_SCE:
case PT_TO_SCX:
case PT_SYSCALL:
if (addr != (void *)1) {
error = ptrace_set_pc(td2,
(u_long)(uintfptr_t)addr);
if (error)
goto out;
}
switch (req) {
case PT_TO_SCE:
p->p_stops |= S_PT_SCE;
break;
case PT_TO_SCX:
p->p_stops |= S_PT_SCX;
break;
case PT_SYSCALL:
p->p_stops |= S_PT_SCE | S_PT_SCX;
break;
}
break;
case PT_DETACH:
/* reset process parent */
if (p->p_oppid != p->p_pptr->p_pid) {
struct proc *pp;
PROC_LOCK(p->p_pptr);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(p->p_pptr);
PROC_UNLOCK(p);
pp = pfind(p->p_oppid);
if (pp == NULL)
pp = initproc;
else
PROC_UNLOCK(pp);
PROC_LOCK(p);
proc_reparent(p, pp);
if (pp == initproc)
p->p_sigparent = SIGCHLD;
}
p->p_flag &= ~(P_TRACED | P_WAITED);
p->p_oppid = 0;
/* should we send SIGCHLD? */
/* childproc_continued(p); */
break;
}
sendsig:
if (proctree_locked) {
sx_xunlock(&proctree_lock);
proctree_locked = 0;
}
p->p_xstat = data;
p->p_xthread = NULL;
if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
/* deliver or queue signal */
td2->td_dbgflags &= ~TDB_XSIG;
td2->td_xsig = data;
if (req == PT_DETACH) {
struct thread *td3;
FOREACH_THREAD_IN_PROC(p, td3) {
td3->td_dbgflags &= ~TDB_SUSPEND;
}
}
/*
* unsuspend all threads, to not let a thread run,
* you should use PT_SUSPEND to suspend it before
* continuing process.
*/
PROC_SLOCK(p);
p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
thread_unsuspend(p);
PROC_SUNLOCK(p);
} else {
if (data)
psignal(p, data);
}
break;
case PT_WRITE_I:
case PT_WRITE_D:
td2->td_dbgflags |= TDB_USERWR;
write = 1;
/* FALLTHROUGH */
case PT_READ_I:
case PT_READ_D:
PROC_UNLOCK(p);
tmp = 0;
/* write = 0 set above */
iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
iov.iov_len = sizeof(int);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = (off_t)(uintptr_t)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 */
}
if (!write)
td->td_retval[0] = tmp;
PROC_LOCK(p);
break;
case PT_IO:
#ifdef COMPAT_FREEBSD32
if (wrap32) {
piod32 = addr;
iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
iov.iov_len = piod32->piod_len;
uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
uio.uio_resid = piod32->piod_len;
} else
#endif
{
piod = addr;
iov.iov_base = piod->piod_addr;
iov.iov_len = piod->piod_len;
uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
uio.uio_resid = piod->piod_len;
}
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_segflg = UIO_USERSPACE;
uio.uio_td = td;
#ifdef COMPAT_FREEBSD32
tmp = wrap32 ? piod32->piod_op : piod->piod_op;
#else
tmp = piod->piod_op;
#endif
switch (tmp) {
case PIOD_READ_D:
case PIOD_READ_I:
uio.uio_rw = UIO_READ;
break;
case PIOD_WRITE_D:
case PIOD_WRITE_I:
td2->td_dbgflags |= TDB_USERWR;
uio.uio_rw = UIO_WRITE;
break;
default:
error = EINVAL;
goto out;
}
PROC_UNLOCK(p);
error = proc_rwmem(p, &uio);
#ifdef COMPAT_FREEBSD32
if (wrap32)
piod32->piod_len -= uio.uio_resid;
else
#endif
piod->piod_len -= uio.uio_resid;
PROC_LOCK(p);
break;
case PT_KILL:
data = SIGKILL;
goto sendsig; /* in PT_CONTINUE above */
case PT_SETREGS:
td2->td_dbgflags |= TDB_USERWR;
error = PROC_WRITE(regs, td2, addr);
break;
case PT_GETREGS:
error = PROC_READ(regs, td2, addr);
break;
case PT_SETFPREGS:
td2->td_dbgflags |= TDB_USERWR;
error = PROC_WRITE(fpregs, td2, addr);
break;
case PT_GETFPREGS:
error = PROC_READ(fpregs, td2, addr);
break;
case PT_SETDBREGS:
td2->td_dbgflags |= TDB_USERWR;
error = PROC_WRITE(dbregs, td2, addr);
break;
case PT_GETDBREGS:
error = PROC_READ(dbregs, td2, addr);
break;
case PT_LWPINFO:
if (data <= 0 ||
#ifdef COMPAT_FREEBSD32
(!wrap32 && data > sizeof(*pl)) ||
(wrap32 && data > sizeof(*pl32))) {
#else
data > sizeof(*pl)) {
#endif
error = EINVAL;
break;
}
#ifdef COMPAT_FREEBSD32
if (wrap32) {
pl = &plr;
pl32 = addr;
} else
#endif
pl = addr;
pl->pl_lwpid = td2->td_tid;
pl->pl_flags = 0;
if (td2->td_dbgflags & TDB_XSIG) {
pl->pl_event = PL_EVENT_SIGNAL;
if (td2->td_dbgksi.ksi_signo != 0 &&
#ifdef COMPAT_FREEBSD32
((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
pl_siginfo) + sizeof(pl->pl_siginfo)) ||
(wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
pl_siginfo) + sizeof(struct siginfo32)))
#else
data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
+ sizeof(pl->pl_siginfo)
#endif
){
pl->pl_flags |= PL_FLAG_SI;
pl->pl_siginfo = td2->td_dbgksi.ksi_info;
}
}
if ((pl->pl_flags & PL_FLAG_SI) == 0)
bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
if (td2->td_dbgflags & TDB_SCE)
pl->pl_flags |= PL_FLAG_SCE;
else if (td2->td_dbgflags & TDB_SCX)
pl->pl_flags |= PL_FLAG_SCX;
if (td2->td_dbgflags & TDB_EXEC)
pl->pl_flags |= PL_FLAG_EXEC;
pl->pl_sigmask = td2->td_sigmask;
pl->pl_siglist = td2->td_siglist;
strcpy(pl->pl_tdname, td2->td_name);
#ifdef COMPAT_FREEBSD32
if (wrap32)
ptrace_lwpinfo_to32(pl, pl32);
#endif
break;
case PT_GETNUMLWPS:
td->td_retval[0] = p->p_numthreads;
break;
case PT_GETLWPLIST:
if (data <= 0) {
error = EINVAL;
break;
}
num = imin(p->p_numthreads, data);
PROC_UNLOCK(p);
buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
tmp = 0;
PROC_LOCK(p);
FOREACH_THREAD_IN_PROC(p, td2) {
if (tmp >= num)
break;
buf[tmp++] = td2->td_tid;
}
PROC_UNLOCK(p);
error = copyout(buf, addr, tmp * sizeof(lwpid_t));
free(buf, M_TEMP);
if (!error)
td->td_retval[0] = tmp;
PROC_LOCK(p);
break;
case PT_VM_TIMESTAMP:
td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
break;
case PT_VM_ENTRY:
PROC_UNLOCK(p);
#ifdef COMPAT_FREEBSD32
if (wrap32)
error = ptrace_vm_entry32(td, p, addr);
else
#endif
error = ptrace_vm_entry(td, p, addr);
PROC_LOCK(p);
break;
default:
#ifdef __HAVE_PTRACE_MACHDEP
if (req >= PT_FIRSTMACH) {
PROC_UNLOCK(p);
error = cpu_ptrace(td2, req, addr, data);
PROC_LOCK(p);
} else
#endif
/* Unknown request. */
error = EINVAL;
break;
}
out:
/* Drop our hold on this process now that the request has completed. */
_PRELE(p);
fail:
PROC_UNLOCK(p);
if (proctree_locked)
sx_xunlock(&proctree_lock);
return (error);
}
#undef PROC_READ
#undef PROC_WRITE
/*
* 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);
p->p_step = 1;
do {
p->p_xstat = val;
p->p_xthread = NULL;
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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