Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_syscall.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
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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_capsicum.h" 42 #include "opt_ktrace.h" 43 #include "opt_kdtrace.h" 44 45 __FBSDID("$FreeBSD$"); 46 47 #include <sys/capability.h> 48 #include <sys/ktr.h> 49 #ifdef KTRACE 50 #include <sys/uio.h> 51 #include <sys/ktrace.h> 52 #endif 53 #include <security/audit/audit.h> 54 55 static inline int 56 syscallenter(struct thread *td, struct syscall_args *sa) 57 { 58 struct proc *p; 59 int error, traced; 60 61 PCPU_INC(cnt.v_syscall); 62 p = td->td_proc; 63 64 td->td_pticks = 0; 65 if (td->td_ucred != p->p_ucred) 66 cred_update_thread(td); 67 traced = (p->p_flag & P_TRACED) != 0; 68 if (traced || td->td_dbgflags & TDB_USERWR) { 69 PROC_LOCK(p); 70 td->td_dbgflags &= ~TDB_USERWR; 71 if (traced) 72 td->td_dbgflags |= TDB_SCE; 73 PROC_UNLOCK(p); 74 } 75 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa); 76 #ifdef KTRACE 77 if (KTRPOINT(td, KTR_SYSCALL)) 78 ktrsyscall(sa->code, sa->narg, sa->args); 79 #endif 80 81 CTR6(KTR_SYSC, 82 "syscall: td=%p pid %d %s (%#lx, %#lx, %#lx)", 83 td, td->td_proc->p_pid, syscallname(p, sa->code), 84 sa->args[0], sa->args[1], sa->args[2]); 85 86 if (error == 0) { 87 STOPEVENT(p, S_SCE, sa->narg); 88 if (p->p_flag & P_TRACED) { 89 PROC_LOCK(p); 90 td->td_dbg_sc_code = sa->code; 91 td->td_dbg_sc_narg = sa->narg; 92 if (p->p_stops & S_PT_SCE) 93 ptracestop((td), SIGTRAP); 94 PROC_UNLOCK(p); 95 } 96 if (td->td_dbgflags & TDB_USERWR) { 97 /* 98 * Reread syscall number and arguments if 99 * debugger modified registers or memory. 100 */ 101 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa); 102 PROC_LOCK(p); 103 td->td_dbg_sc_code = sa->code; 104 td->td_dbg_sc_narg = sa->narg; 105 PROC_UNLOCK(p); 106 #ifdef KTRACE 107 if (KTRPOINT(td, KTR_SYSCALL)) 108 ktrsyscall(sa->code, sa->narg, sa->args); 109 #endif 110 if (error != 0) 111 goto retval; 112 } 113 114 #ifdef CAPABILITY_MODE 115 /* 116 * In capability mode, we only allow access to system calls 117 * flagged with SYF_CAPENABLED. 118 */ 119 if (IN_CAPABILITY_MODE(td) && 120 !(sa->callp->sy_flags & SYF_CAPENABLED)) { 121 error = ECAPMODE; 122 goto retval; 123 } 124 #endif 125 126 error = syscall_thread_enter(td, sa->callp); 127 if (error != 0) 128 goto retval; 129 130 #ifdef KDTRACE_HOOKS 131 /* 132 * If the systrace module has registered it's probe 133 * callback and if there is a probe active for the 134 * syscall 'entry', process the probe. 135 */ 136 if (systrace_probe_func != NULL && sa->callp->sy_entry != 0) 137 (*systrace_probe_func)(sa->callp->sy_entry, sa->code, 138 sa->callp, sa->args, 0); 139 #endif 140 141 AUDIT_SYSCALL_ENTER(sa->code, td); 142 error = (sa->callp->sy_call)(td, sa->args); 143 AUDIT_SYSCALL_EXIT(error, td); 144 145 /* Save the latest error return value. */ 146 if ((td->td_pflags & TDP_NERRNO) == 0) 147 td->td_errno = error; 148 149 #ifdef KDTRACE_HOOKS 150 /* 151 * If the systrace module has registered it's probe 152 * callback and if there is a probe active for the 153 * syscall 'return', process the probe. 154 */ 155 if (systrace_probe_func != NULL && sa->callp->sy_return != 0) 156 (*systrace_probe_func)(sa->callp->sy_return, sa->code, 157 sa->callp, NULL, (error) ? -1 : td->td_retval[0]); 158 #endif 159 syscall_thread_exit(td, sa->callp); 160 CTR4(KTR_SYSC, "syscall: p=%p error=%d return %#lx %#lx", 161 p, error, td->td_retval[0], td->td_retval[1]); 162 } 163 retval: 164 if (traced) { 165 PROC_LOCK(p); 166 td->td_dbgflags &= ~TDB_SCE; 167 PROC_UNLOCK(p); 168 } 169 (p->p_sysent->sv_set_syscall_retval)(td, error); 170 return (error); 171 } 172 173 static inline void 174 syscallret(struct thread *td, int error, struct syscall_args *sa __unused) 175 { 176 struct proc *p, *p2; 177 int traced; 178 179 p = td->td_proc; 180 181 /* 182 * Check for misbehavior. 183 */ 184 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 185 syscallname(p, sa->code)); 186 KASSERT(td->td_critnest == 0, 187 ("System call %s returning in a critical section", 188 syscallname(p, sa->code))); 189 KASSERT(td->td_locks == 0, 190 ("System call %s returning with %d locks held", 191 syscallname(p, sa->code), td->td_locks)); 192 KASSERT((td->td_pflags & TDP_NOFAULTING) == 0, 193 ("System call %s returning with pagefaults disabled", 194 syscallname(p, sa->code))); 195 KASSERT((td->td_pflags & TDP_NOSLEEPING) == 0, 196 ("System call %s returning with sleep disabled", 197 syscallname(p, sa->code))); 198 199 /* 200 * Handle reschedule and other end-of-syscall issues 201 */ 202 userret(td, td->td_frame); 203 204 CTR4(KTR_SYSC, "syscall %s exit thread %p pid %d proc %s", 205 syscallname(p, sa->code), td, td->td_proc->p_pid, td->td_name); 206 207 #ifdef KTRACE 208 if (KTRPOINT(td, KTR_SYSRET)) { 209 ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ? 210 error : td->td_errno, td->td_retval[0]); 211 } 212 #endif 213 td->td_pflags &= ~TDP_NERRNO; 214 215 if (p->p_flag & P_TRACED) { 216 traced = 1; 217 PROC_LOCK(p); 218 td->td_dbgflags |= TDB_SCX; 219 PROC_UNLOCK(p); 220 } else 221 traced = 0; 222 /* 223 * This works because errno is findable through the 224 * register set. If we ever support an emulation where this 225 * is not the case, this code will need to be revisited. 226 */ 227 STOPEVENT(p, S_SCX, sa->code); 228 if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) { 229 PROC_LOCK(p); 230 /* 231 * If tracing the execed process, trap to the debugger 232 * so that breakpoints can be set before the program 233 * executes. If debugger requested tracing of syscall 234 * returns, do it now too. 235 */ 236 if (traced && 237 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 || 238 (p->p_stops & S_PT_SCX) != 0)) 239 ptracestop(td, SIGTRAP); 240 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK); 241 PROC_UNLOCK(p); 242 } 243 244 if (td->td_pflags & TDP_RFPPWAIT) { 245 /* 246 * Preserve synchronization semantics of vfork. If 247 * waiting for child to exec or exit, fork set 248 * P_PPWAIT on child, and there we sleep on our proc 249 * (in case of exit). 250 * 251 * Do it after the ptracestop() above is finished, to 252 * not block our debugger until child execs or exits 253 * to finish vfork wait. 254 */ 255 td->td_pflags &= ~TDP_RFPPWAIT; 256 p2 = td->td_rfppwait_p; 257 PROC_LOCK(p2); 258 while (p2->p_flag & P_PPWAIT) 259 cv_wait(&p2->p_pwait, &p2->p_mtx); 260 PROC_UNLOCK(p2); 261 } 262 }
Cache object: 91cbf1bf076ba84d53835a7f4ebd75ca
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