1 /*-
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>
6 *
7 * This code is derived from software contributed to Berkeley by
8 * the University of Utah, and William Jolitz.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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.
25 *
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
36 * SUCH DAMAGE.
37 *
38 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
39 */
40
41 #include "opt_ktrace.h"
42 #include "opt_kdtrace.h"
43
44 __FBSDID("$FreeBSD: releng/8.3/sys/kern/subr_syscall.c 231072 2012-02-06 10:35:21Z kib $");
45
46 #include <sys/ktr.h>
47 #ifdef KTRACE
48 #include <sys/uio.h>
49 #include <sys/ktrace.h>
50 #endif
51 #include <security/audit/audit.h>
52
53 static inline int
54 syscallenter(struct thread *td, struct syscall_args *sa)
55 {
56 struct proc *p;
57 int error, traced;
58
59 PCPU_INC(cnt.v_syscall);
60 p = td->td_proc;
61 td->td_syscalls++;
62
63 td->td_pticks = 0;
64 if (td->td_ucred != p->p_ucred)
65 cred_update_thread(td);
66 if (p->p_flag & P_TRACED) {
67 traced = 1;
68 PROC_LOCK(p);
69 td->td_dbgflags &= ~TDB_USERWR;
70 td->td_dbgflags |= TDB_SCE;
71 PROC_UNLOCK(p);
72 } else
73 traced = 0;
74 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
75 #ifdef KTRACE
76 if (KTRPOINT(td, KTR_SYSCALL))
77 ktrsyscall(sa->code, sa->narg, sa->args);
78 #endif
79
80 CTR6(KTR_SYSC,
81 "syscall: td=%p pid %d %s (%#lx, %#lx, %#lx)",
82 td, td->td_proc->p_pid, syscallname(p, sa->code),
83 sa->args[0], sa->args[1], sa->args[2]);
84
85 if (error == 0) {
86 STOPEVENT(p, S_SCE, sa->narg);
87 PTRACESTOP_SC(p, td, S_PT_SCE);
88 if (td->td_dbgflags & TDB_USERWR) {
89 /*
90 * Reread syscall number and arguments if
91 * debugger modified registers or memory.
92 */
93 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
94 #ifdef KTRACE
95 if (KTRPOINT(td, KTR_SYSCALL))
96 ktrsyscall(sa->code, sa->narg, sa->args);
97 #endif
98 if (error != 0)
99 goto retval;
100 }
101
102 #ifdef KDTRACE_HOOKS
103 /*
104 * If the systrace module has registered it's probe
105 * callback and if there is a probe active for the
106 * syscall 'entry', process the probe.
107 */
108 if (systrace_probe_func != NULL && sa->callp->sy_entry != 0)
109 (*systrace_probe_func)(sa->callp->sy_entry, sa->code,
110 sa->callp, sa->args, 0);
111 #endif
112
113 AUDIT_SYSCALL_ENTER(sa->code, td);
114 error = (sa->callp->sy_call)(td, sa->args);
115 AUDIT_SYSCALL_EXIT(error, td);
116
117 /* Save the latest error return value. */
118 td->td_errno = error;
119
120 #ifdef KDTRACE_HOOKS
121 /*
122 * If the systrace module has registered it's probe
123 * callback and if there is a probe active for the
124 * syscall 'return', process the probe.
125 */
126 if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
127 (*systrace_probe_func)(sa->callp->sy_return, sa->code,
128 sa->callp, NULL, (error) ? -1 : td->td_retval[0]);
129 #endif
130 CTR4(KTR_SYSC, "syscall: p=%p error=%d return %#lx %#lx",
131 p, error, td->td_retval[0], td->td_retval[1]);
132 }
133 retval:
134 if (traced) {
135 PROC_LOCK(p);
136 td->td_dbgflags &= ~TDB_SCE;
137 PROC_UNLOCK(p);
138 }
139 (p->p_sysent->sv_set_syscall_retval)(td, error);
140 return (error);
141 }
142
143 static inline void
144 syscallret(struct thread *td, int error, struct syscall_args *sa __unused)
145 {
146 struct proc *p;
147 int traced;
148
149 p = td->td_proc;
150
151 /*
152 * Check for misbehavior.
153 */
154 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
155 syscallname(p, sa->code));
156 KASSERT(td->td_critnest == 0,
157 ("System call %s returning in a critical section",
158 syscallname(p, sa->code)));
159 KASSERT(td->td_locks == 0,
160 ("System call %s returning with %d locks held",
161 syscallname(p, sa->code), td->td_locks));
162
163 /*
164 * Handle reschedule and other end-of-syscall issues
165 */
166 userret(td, td->td_frame);
167
168 CTR4(KTR_SYSC, "syscall %s exit thread %p pid %d proc %s",
169 syscallname(p, sa->code), td, td->td_proc->p_pid, td->td_name);
170
171 #ifdef KTRACE
172 if (KTRPOINT(td, KTR_SYSRET))
173 ktrsysret(sa->code, error, td->td_retval[0]);
174 #endif
175
176 if (p->p_flag & P_TRACED) {
177 traced = 1;
178 PROC_LOCK(p);
179 td->td_dbgflags |= TDB_SCX;
180 PROC_UNLOCK(p);
181 } else
182 traced = 0;
183 /*
184 * This works because errno is findable through the
185 * register set. If we ever support an emulation where this
186 * is not the case, this code will need to be revisited.
187 */
188 STOPEVENT(p, S_SCX, sa->code);
189 if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) {
190 PROC_LOCK(p);
191 /*
192 * If tracing the execed process, trap to the debugger
193 * so that breakpoints can be set before the program
194 * executes. If debugger requested tracing of syscall
195 * returns, do it now too.
196 */
197 if (traced &&
198 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
199 (p->p_stops & S_PT_SCX) != 0))
200 ptracestop(td, SIGTRAP);
201 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
202 PROC_UNLOCK(p);
203 }
204 }
Cache object: 423127248bc6b2e9bb1e37a651c44ef8
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