/*- * Copyright (C) 1994, David Greenman * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * Copyright (C) 2010 Konstantin Belousov * * This code is derived from software contributed to Berkeley by * the University of Utah, and William Jolitz. * * 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 the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 */ #include "opt_ktrace.h" #include "opt_kdtrace.h" __FBSDID("$FreeBSD$"); #include #ifdef KTRACE #include #include #endif #include static inline int syscallenter(struct thread *td, struct syscall_args *sa) { struct proc *p; int error, traced; PCPU_INC(cnt.v_syscall); p = td->td_proc; td->td_syscalls++; td->td_pticks = 0; if (td->td_ucred != p->p_ucred) cred_update_thread(td); if (p->p_flag & P_TRACED) { traced = 1; PROC_LOCK(p); td->td_dbgflags &= ~TDB_USERWR; td->td_dbgflags |= TDB_SCE; PROC_UNLOCK(p); } else traced = 0; error = (p->p_sysent->sv_fetch_syscall_args)(td, sa); #ifdef KTRACE if (KTRPOINT(td, KTR_SYSCALL)) ktrsyscall(sa->code, sa->narg, sa->args); #endif CTR6(KTR_SYSC, "syscall: td=%p pid %d %s (%#lx, %#lx, %#lx)", td, td->td_proc->p_pid, syscallname(p, sa->code), sa->args[0], sa->args[1], sa->args[2]); if (error == 0) { STOPEVENT(p, S_SCE, sa->narg); PTRACESTOP_SC(p, td, S_PT_SCE); if (td->td_dbgflags & TDB_USERWR) { /* * Reread syscall number and arguments if * debugger modified registers or memory. */ error = (p->p_sysent->sv_fetch_syscall_args)(td, sa); #ifdef KTRACE if (KTRPOINT(td, KTR_SYSCALL)) ktrsyscall(sa->code, sa->narg, sa->args); #endif if (error != 0) goto retval; } #ifdef KDTRACE_HOOKS /* * If the systrace module has registered it's probe * callback and if there is a probe active for the * syscall 'entry', process the probe. */ if (systrace_probe_func != NULL && sa->callp->sy_entry != 0) (*systrace_probe_func)(sa->callp->sy_entry, sa->code, sa->callp, sa->args, 0); #endif AUDIT_SYSCALL_ENTER(sa->code, td); error = (sa->callp->sy_call)(td, sa->args); AUDIT_SYSCALL_EXIT(error, td); /* Save the latest error return value. */ if ((td->td_pflags & TDP_NERRNO) == 0) td->td_errno = error; #ifdef KDTRACE_HOOKS /* * If the systrace module has registered it's probe * callback and if there is a probe active for the * syscall 'return', process the probe. */ if (systrace_probe_func != NULL && sa->callp->sy_return != 0) (*systrace_probe_func)(sa->callp->sy_return, sa->code, sa->callp, NULL, (error) ? -1 : td->td_retval[0]); #endif CTR4(KTR_SYSC, "syscall: p=%p error=%d return %#lx %#lx", p, error, td->td_retval[0], td->td_retval[1]); } retval: if (traced) { PROC_LOCK(p); td->td_dbgflags &= ~TDB_SCE; PROC_UNLOCK(p); } (p->p_sysent->sv_set_syscall_retval)(td, error); return (error); } static inline void syscallret(struct thread *td, int error, struct syscall_args *sa __unused) { struct proc *p; int traced; p = td->td_proc; /* * Check for misbehavior. */ WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", syscallname(p, sa->code)); KASSERT(td->td_critnest == 0, ("System call %s returning in a critical section", syscallname(p, sa->code))); KASSERT(td->td_locks == 0, ("System call %s returning with %d locks held", syscallname(p, sa->code), td->td_locks)); /* * Handle reschedule and other end-of-syscall issues */ userret(td, td->td_frame); CTR4(KTR_SYSC, "syscall %s exit thread %p pid %d proc %s", syscallname(p, sa->code), td, td->td_proc->p_pid, td->td_name); #ifdef KTRACE if (KTRPOINT(td, KTR_SYSRET)) { ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ? error : td->td_errno, td->td_retval[0]); } #endif td->td_pflags &= ~TDP_NERRNO; if (p->p_flag & P_TRACED) { traced = 1; PROC_LOCK(p); td->td_dbgflags |= TDB_SCX; PROC_UNLOCK(p); } else traced = 0; /* * This works because errno is findable through the * register set. If we ever support an emulation where this * is not the case, this code will need to be revisited. */ STOPEVENT(p, S_SCX, sa->code); if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) { PROC_LOCK(p); /* * If tracing the execed process, trap to the debugger * so that breakpoints can be set before the program * executes. If debugger requested tracing of syscall * returns, do it now too. */ if (traced && ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 || (p->p_stops & S_PT_SCX) != 0)) ptracestop(td, SIGTRAP); td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK); PROC_UNLOCK(p); } }