2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 * Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
7 * This code is derived from software contributed to Berkeley by
8 * the University of Utah, and William Jolitz.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
41 #include "opt_capsicum.h"
42 #include "opt_ktrace.h"
44 __FBSDID("$FreeBSD$");
46 #include <sys/capsicum.h>
50 #include <sys/ktrace.h>
52 #include <security/audit/audit.h>
55 syscallenter(struct thread *td, struct syscall_args *sa)
60 PCPU_INC(cnt.v_syscall);
64 if (td->td_cowgen != p->p_cowgen)
65 thread_cow_update(td);
66 traced = (p->p_flag & P_TRACED) != 0;
67 if (traced || td->td_dbgflags & TDB_USERWR) {
69 td->td_dbgflags &= ~TDB_USERWR;
71 td->td_dbgflags |= TDB_SCE;
74 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
76 if (KTRPOINT(td, KTR_SYSCALL))
77 ktrsyscall(sa->code, sa->narg, sa->args);
79 KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
80 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
81 "arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
85 STOPEVENT(p, S_SCE, sa->narg);
86 if (p->p_flag & P_TRACED) {
88 td->td_dbg_sc_code = sa->code;
89 td->td_dbg_sc_narg = sa->narg;
90 if (p->p_ptevents & PTRACE_SCE)
91 ptracestop((td), SIGTRAP);
94 if (td->td_dbgflags & TDB_USERWR) {
96 * Reread syscall number and arguments if
97 * debugger modified registers or memory.
99 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
101 td->td_dbg_sc_code = sa->code;
102 td->td_dbg_sc_narg = sa->narg;
105 if (KTRPOINT(td, KTR_SYSCALL))
106 ktrsyscall(sa->code, sa->narg, sa->args);
112 #ifdef CAPABILITY_MODE
114 * In capability mode, we only allow access to system calls
115 * flagged with SYF_CAPENABLED.
117 if (IN_CAPABILITY_MODE(td) &&
118 !(sa->callp->sy_flags & SYF_CAPENABLED)) {
124 error = syscall_thread_enter(td, sa->callp);
129 /* Give the syscall:::entry DTrace probe a chance to fire. */
130 if (systrace_probe_func != NULL && sa->callp->sy_entry != 0)
131 (*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0);
134 AUDIT_SYSCALL_ENTER(sa->code, td);
135 error = (sa->callp->sy_call)(td, sa->args);
136 AUDIT_SYSCALL_EXIT(error, td);
138 /* Save the latest error return value. */
139 if ((td->td_pflags & TDP_NERRNO) == 0)
140 td->td_errno = error;
143 /* Give the syscall:::return DTrace probe a chance to fire. */
144 if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
145 (*systrace_probe_func)(sa, SYSTRACE_RETURN,
146 error ? -1 : td->td_retval[0]);
148 syscall_thread_exit(td, sa->callp);
151 KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),
152 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error,
153 "retval0:%#lx", td->td_retval[0], "retval1:%#lx",
157 td->td_dbgflags &= ~TDB_SCE;
160 (p->p_sysent->sv_set_syscall_retval)(td, error);
165 syscallret(struct thread *td, int error, struct syscall_args *sa)
171 KASSERT((td->td_pflags & TDP_FORKING) == 0,
172 ("fork() did not clear TDP_FORKING upon completion"));
175 if ((trap_enotcap || (p->p_flag2 & P2_TRAPCAP) != 0) &&
176 IN_CAPABILITY_MODE(td)) {
177 error1 = (td->td_pflags & TDP_NERRNO) == 0 ? error :
179 if (error1 == ENOTCAPABLE || error1 == ECAPMODE) {
180 ksiginfo_init_trap(&ksi);
181 ksi.ksi_signo = SIGTRAP;
182 ksi.ksi_errno = error1;
183 ksi.ksi_code = TRAP_CAP;
184 trapsignal(td, &ksi);
189 * Handle reschedule and other end-of-syscall issues
191 userret(td, td->td_frame);
194 if (KTRPOINT(td, KTR_SYSRET)) {
195 ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ?
196 error : td->td_errno, td->td_retval[0]);
199 td->td_pflags &= ~TDP_NERRNO;
201 if (p->p_flag & P_TRACED) {
204 td->td_dbgflags |= TDB_SCX;
209 * This works because errno is findable through the
210 * register set. If we ever support an emulation where this
211 * is not the case, this code will need to be revisited.
213 STOPEVENT(p, S_SCX, sa->code);
214 if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) {
217 * If tracing the execed process, trap to the debugger
218 * so that breakpoints can be set before the program
219 * executes. If debugger requested tracing of syscall
220 * returns, do it now too.
223 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
224 (p->p_ptevents & PTRACE_SCX) != 0))
225 ptracestop(td, SIGTRAP);
226 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
230 if (td->td_pflags & TDP_RFPPWAIT) {
232 * Preserve synchronization semantics of vfork. If
233 * waiting for child to exec or exit, fork set
234 * P_PPWAIT on child, and there we sleep on our proc
237 * Do it after the ptracestop() above is finished, to
238 * not block our debugger until child execs or exits
239 * to finish vfork wait.
241 td->td_pflags &= ~TDP_RFPPWAIT;
242 p2 = td->td_rfppwait_p;
245 while (p2->p_flag & P_PPWAIT) {
247 if (thread_suspend_check_needed()) {
249 thread_suspend_check(0);
255 cv_timedwait(&p2->p_pwait, &p2->p_mtx, hz);
259 if (td->td_dbgflags & TDB_VFORK) {
261 if (p->p_ptevents & PTRACE_VFORK)
262 ptracestop(td, SIGTRAP);
263 td->td_dbgflags &= ~TDB_VFORK;