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"
43 #include "opt_kdtrace.h"
45 __FBSDID("$FreeBSD$");
47 #include <sys/capability.h>
51 #include <sys/ktrace.h>
53 #include <security/audit/audit.h>
56 syscallenter(struct thread *td, struct syscall_args *sa)
61 PCPU_INC(cnt.v_syscall);
65 if (td->td_ucred != p->p_ucred)
66 cred_update_thread(td);
67 if (p->p_flag & P_TRACED) {
70 td->td_dbgflags &= ~TDB_USERWR;
71 td->td_dbgflags |= TDB_SCE;
75 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
77 if (KTRPOINT(td, KTR_SYSCALL))
78 ktrsyscall(sa->code, sa->narg, sa->args);
80 KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
81 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
82 "arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
86 STOPEVENT(p, S_SCE, sa->narg);
87 if (p->p_flag & P_TRACED && p->p_stops & S_PT_SCE) {
89 ptracestop((td), SIGTRAP);
92 if (td->td_dbgflags & TDB_USERWR) {
94 * Reread syscall number and arguments if
95 * debugger modified registers or memory.
97 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
99 if (KTRPOINT(td, KTR_SYSCALL))
100 ktrsyscall(sa->code, sa->narg, sa->args);
106 #ifdef CAPABILITY_MODE
108 * In capability mode, we only allow access to system calls
109 * flagged with SYF_CAPENABLED.
111 if (IN_CAPABILITY_MODE(td) &&
112 !(sa->callp->sy_flags & SYF_CAPENABLED)) {
118 error = syscall_thread_enter(td, sa->callp);
124 * If the systrace module has registered it's probe
125 * callback and if there is a probe active for the
126 * syscall 'entry', process the probe.
128 if (systrace_probe_func != NULL && sa->callp->sy_entry != 0)
129 (*systrace_probe_func)(sa->callp->sy_entry, sa->code,
130 sa->callp, sa->args, 0);
133 AUDIT_SYSCALL_ENTER(sa->code, td);
134 error = (sa->callp->sy_call)(td, sa->args);
135 AUDIT_SYSCALL_EXIT(error, td);
137 /* Save the latest error return value. */
138 if ((td->td_pflags & TDP_NERRNO) == 0)
139 td->td_errno = error;
143 * If the systrace module has registered it's probe
144 * callback and if there is a probe active for the
145 * syscall 'return', process the probe.
147 if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
148 (*systrace_probe_func)(sa->callp->sy_return, sa->code,
149 sa->callp, NULL, (error) ? -1 : td->td_retval[0]);
151 syscall_thread_exit(td, sa->callp);
154 KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),
155 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error,
156 "retval0:%#lx", td->td_retval[0], "retval1:%#lx",
160 td->td_dbgflags &= ~TDB_SCE;
163 (p->p_sysent->sv_set_syscall_retval)(td, error);
168 syscallret(struct thread *td, int error, struct syscall_args *sa __unused)
176 * Handle reschedule and other end-of-syscall issues
178 userret(td, td->td_frame);
181 if (KTRPOINT(td, KTR_SYSRET)) {
182 ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ?
183 error : td->td_errno, td->td_retval[0]);
186 td->td_pflags &= ~TDP_NERRNO;
188 if (p->p_flag & P_TRACED) {
191 td->td_dbgflags |= TDB_SCX;
196 * This works because errno is findable through the
197 * register set. If we ever support an emulation where this
198 * is not the case, this code will need to be revisited.
200 STOPEVENT(p, S_SCX, sa->code);
201 if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) {
204 * If tracing the execed process, trap to the debugger
205 * so that breakpoints can be set before the program
206 * executes. If debugger requested tracing of syscall
207 * returns, do it now too.
210 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
211 (p->p_stops & S_PT_SCX) != 0))
212 ptracestop(td, SIGTRAP);
213 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
217 if (td->td_pflags & TDP_RFPPWAIT) {
219 * Preserve synchronization semantics of vfork. If
220 * waiting for child to exec or exit, fork set
221 * P_PPWAIT on child, and there we sleep on our proc
224 * Do it after the ptracestop() above is finished, to
225 * not block our debugger until child execs or exits
226 * to finish vfork wait.
228 td->td_pflags &= ~TDP_RFPPWAIT;
229 p2 = td->td_rfppwait_p;
231 while (p2->p_flag & P_PPWAIT)
232 cv_wait(&p2->p_pwait, &p2->p_mtx);