2 * SPDX-License-Identifier: BSD-4-Clause
4 * Copyright (C) 1994, David Greenman
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 * Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
9 * This code is derived from software contributed to Berkeley by
10 * the University of Utah, and William Jolitz.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
43 #include "opt_capsicum.h"
44 #include "opt_ktrace.h"
46 __FBSDID("$FreeBSD$");
48 #include <sys/capsicum.h>
50 #include <sys/vmmeter.h>
53 #include <sys/ktrace.h>
55 #include <security/audit/audit.h>
58 syscallenter(struct thread *td)
61 struct syscall_args *sa;
64 VM_CNT_INC(v_syscall);
69 if (td->td_cowgen != p->p_cowgen)
70 thread_cow_update(td);
71 traced = (p->p_flag & P_TRACED) != 0;
72 if (traced || td->td_dbgflags & TDB_USERWR) {
74 td->td_dbgflags &= ~TDB_USERWR;
76 td->td_dbgflags |= TDB_SCE;
79 error = (p->p_sysent->sv_fetch_syscall_args)(td);
81 if (KTRPOINT(td, KTR_SYSCALL))
82 ktrsyscall(sa->code, sa->narg, sa->args);
84 KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
85 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
86 "arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
90 STOPEVENT(p, S_SCE, sa->narg);
91 if (p->p_flag & P_TRACED) {
93 if (p->p_ptevents & PTRACE_SCE)
94 ptracestop((td), SIGTRAP, NULL);
97 if (td->td_dbgflags & TDB_USERWR) {
99 * Reread syscall number and arguments if
100 * debugger modified registers or memory.
102 error = (p->p_sysent->sv_fetch_syscall_args)(td);
104 if (KTRPOINT(td, KTR_SYSCALL))
105 ktrsyscall(sa->code, sa->narg, sa->args);
111 #ifdef CAPABILITY_MODE
113 * In capability mode, we only allow access to system calls
114 * flagged with SYF_CAPENABLED.
116 if (IN_CAPABILITY_MODE(td) &&
117 !(sa->callp->sy_flags & SYF_CAPENABLED)) {
123 error = syscall_thread_enter(td, sa->callp);
128 /* Give the syscall:::entry DTrace probe a chance to fire. */
129 if (__predict_false(systrace_enabled &&
130 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 (__predict_false(systrace_enabled &&
145 sa->callp->sy_return != 0))
146 (*systrace_probe_func)(sa, SYSTRACE_RETURN,
147 error ? -1 : td->td_retval[0]);
149 syscall_thread_exit(td, sa->callp);
152 KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),
153 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error,
154 "retval0:%#lx", td->td_retval[0], "retval1:%#lx",
158 td->td_dbgflags &= ~TDB_SCE;
161 (p->p_sysent->sv_set_syscall_retval)(td, error);
166 syscallret(struct thread *td, int error)
169 struct syscall_args *sa;
173 KASSERT((td->td_pflags & TDP_FORKING) == 0,
174 ("fork() did not clear TDP_FORKING upon completion"));
178 if ((trap_enotcap || (p->p_flag2 & P2_TRAPCAP) != 0) &&
179 IN_CAPABILITY_MODE(td)) {
180 error1 = (td->td_pflags & TDP_NERRNO) == 0 ? error :
182 if (error1 == ENOTCAPABLE || error1 == ECAPMODE) {
183 ksiginfo_init_trap(&ksi);
184 ksi.ksi_signo = SIGTRAP;
185 ksi.ksi_errno = error1;
186 ksi.ksi_code = TRAP_CAP;
187 trapsignal(td, &ksi);
192 * Handle reschedule and other end-of-syscall issues
194 userret(td, td->td_frame);
197 if (KTRPOINT(td, KTR_SYSRET)) {
198 ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ?
199 error : td->td_errno, td->td_retval[0]);
202 td->td_pflags &= ~TDP_NERRNO;
204 if (p->p_flag & P_TRACED) {
207 td->td_dbgflags |= TDB_SCX;
212 * This works because errno is findable through the
213 * register set. If we ever support an emulation where this
214 * is not the case, this code will need to be revisited.
216 STOPEVENT(p, S_SCX, sa->code);
217 if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) {
220 * If tracing the execed process, trap to the debugger
221 * so that breakpoints can be set before the program
222 * executes. If debugger requested tracing of syscall
223 * returns, do it now too.
226 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
227 (p->p_ptevents & PTRACE_SCX) != 0))
228 ptracestop(td, SIGTRAP, NULL);
229 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
233 if (td->td_pflags & TDP_RFPPWAIT) {
235 * Preserve synchronization semantics of vfork. If
236 * waiting for child to exec or exit, fork set
237 * P_PPWAIT on child, and there we sleep on our proc
240 * Do it after the ptracestop() above is finished, to
241 * not block our debugger until child execs or exits
242 * to finish vfork wait.
244 td->td_pflags &= ~TDP_RFPPWAIT;
245 p2 = td->td_rfppwait_p;
248 while (p2->p_flag & P_PPWAIT) {
250 if (thread_suspend_check_needed()) {
252 thread_suspend_check(0);
258 cv_timedwait(&p2->p_pwait, &p2->p_mtx, hz);
262 if (td->td_dbgflags & TDB_VFORK) {
264 if (p->p_ptevents & PTRACE_VFORK)
265 ptracestop(td, SIGTRAP, NULL);
266 td->td_dbgflags &= ~TDB_VFORK;