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 * SPDX-License-Identifier: BSD-4-Clause 3 * 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> 8 * 9 * This code is derived from software contributed to Berkeley by 10 * the University of Utah, and William Jolitz. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 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. 27 * 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 38 * SUCH DAMAGE. 39 * 40 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 41 */ 42 43 #include "opt_capsicum.h" 44 #include "opt_ktrace.h" 45 46 __FBSDID("$FreeBSD$"); 47 48 #include <sys/capsicum.h> 49 #include <sys/ktr.h> 50 #include <sys/vmmeter.h> 51 #ifdef KTRACE 52 #include <sys/uio.h> 53 #include <sys/ktrace.h> 54 #endif 55 #include <security/audit/audit.h> 56 57 static inline void 58 syscallenter(struct thread *td) 59 { 60 struct proc *p; 61 struct syscall_args *sa; 62 struct sysent *se; 63 int error, traced; 64 bool sy_thr_static; 65 66 VM_CNT_INC(v_syscall); 67 p = td->td_proc; 68 sa = &td->td_sa; 69 70 td->td_pticks = 0; 71 if (__predict_false(td->td_cowgen != p->p_cowgen)) 72 thread_cow_update(td); 73 traced = (p->p_flag & P_TRACED) != 0; 74 if (__predict_false(traced || td->td_dbgflags & TDB_USERWR)) { 75 PROC_LOCK(p); 76 td->td_dbgflags &= ~TDB_USERWR; 77 if (traced) 78 td->td_dbgflags |= TDB_SCE; 79 PROC_UNLOCK(p); 80 } 81 error = (p->p_sysent->sv_fetch_syscall_args)(td); 82 se = sa->callp; 83 #ifdef KTRACE 84 if (KTRPOINT(td, KTR_SYSCALL)) 85 ktrsyscall(sa->code, se->sy_narg, sa->args); 86 #endif 87 KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code), 88 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0], 89 "arg1:%p", sa->args[1], "arg2:%p", sa->args[2]); 90 91 if (__predict_false(error != 0)) { 92 td->td_errno = error; 93 goto retval; 94 } 95 96 if (__predict_false(traced)) { 97 PROC_LOCK(p); 98 if (p->p_ptevents & PTRACE_SCE) 99 ptracestop((td), SIGTRAP, NULL); 100 PROC_UNLOCK(p); 101 102 if ((td->td_dbgflags & TDB_USERWR) != 0) { 103 /* 104 * Reread syscall number and arguments if debugger 105 * modified registers or memory. 106 */ 107 error = (p->p_sysent->sv_fetch_syscall_args)(td); 108 se = sa->callp; 109 #ifdef KTRACE 110 if (KTRPOINT(td, KTR_SYSCALL)) 111 ktrsyscall(sa->code, se->sy_narg, sa->args); 112 #endif 113 if (error != 0) { 114 td->td_errno = error; 115 goto retval; 116 } 117 } 118 } 119 120 #ifdef CAPABILITY_MODE 121 /* 122 * In capability mode, we only allow access to system calls 123 * flagged with SYF_CAPENABLED. 124 */ 125 if (__predict_false(IN_CAPABILITY_MODE(td) && 126 (se->sy_flags & SYF_CAPENABLED) == 0)) { 127 td->td_errno = error = ECAPMODE; 128 goto retval; 129 } 130 #endif 131 132 /* 133 * Fetch fast sigblock value at the time of syscall entry to 134 * handle sleepqueue primitives which might call cursig(). 135 */ 136 if (__predict_false(sigfastblock_fetch_always)) 137 (void)sigfastblock_fetch(td); 138 139 /* Let system calls set td_errno directly. */ 140 KASSERT((td->td_pflags & TDP_NERRNO) == 0, 141 ("%s: TDP_NERRNO set", __func__)); 142 143 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0; 144 145 if (__predict_false(SYSTRACE_ENABLED() || 146 AUDIT_SYSCALL_ENTER(sa->code, td) || 147 !sy_thr_static)) { 148 if (!sy_thr_static) { 149 error = syscall_thread_enter(td, se); 150 if (error != 0) { 151 td->td_errno = error; 152 goto retval; 153 } 154 } 155 156 #ifdef KDTRACE_HOOKS 157 /* Give the syscall:::entry DTrace probe a chance to fire. */ 158 if (__predict_false(se->sy_entry != 0)) 159 (*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0); 160 #endif 161 error = (se->sy_call)(td, sa->args); 162 /* Save the latest error return value. */ 163 if (__predict_false((td->td_pflags & TDP_NERRNO) != 0)) 164 td->td_pflags &= ~TDP_NERRNO; 165 else 166 td->td_errno = error; 167 168 /* 169 * Note that some syscall implementations (e.g., sys_execve) 170 * will commit the audit record just before their final return. 171 * These were done under the assumption that nothing of interest 172 * would happen between their return and here, where we would 173 * normally commit the audit record. These assumptions will 174 * need to be revisited should any substantial logic be added 175 * above. 176 */ 177 AUDIT_SYSCALL_EXIT(error, td); 178 179 #ifdef KDTRACE_HOOKS 180 /* Give the syscall:::return DTrace probe a chance to fire. */ 181 if (__predict_false(se->sy_return != 0)) 182 (*systrace_probe_func)(sa, SYSTRACE_RETURN, 183 error ? -1 : td->td_retval[0]); 184 #endif 185 186 if (!sy_thr_static) 187 syscall_thread_exit(td, se); 188 } else { 189 error = (se->sy_call)(td, sa->args); 190 /* Save the latest error return value. */ 191 if (__predict_false((td->td_pflags & TDP_NERRNO) != 0)) 192 td->td_pflags &= ~TDP_NERRNO; 193 else 194 td->td_errno = error; 195 } 196 197 retval: 198 KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code), 199 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error, 200 "retval0:%#lx", td->td_retval[0], "retval1:%#lx", 201 td->td_retval[1]); 202 if (__predict_false(traced)) { 203 PROC_LOCK(p); 204 td->td_dbgflags &= ~TDB_SCE; 205 PROC_UNLOCK(p); 206 } 207 (p->p_sysent->sv_set_syscall_retval)(td, error); 208 } 209 210 static inline void 211 syscallret(struct thread *td) 212 { 213 struct proc *p; 214 struct syscall_args *sa; 215 ksiginfo_t ksi; 216 int traced; 217 218 KASSERT((td->td_pflags & TDP_FORKING) == 0, 219 ("fork() did not clear TDP_FORKING upon completion")); 220 KASSERT(td->td_errno != ERELOOKUP, 221 ("ERELOOKUP not consumed syscall %d", td->td_sa.code)); 222 223 p = td->td_proc; 224 sa = &td->td_sa; 225 if (__predict_false(td->td_errno == ENOTCAPABLE || 226 td->td_errno == ECAPMODE)) { 227 if ((trap_enotcap || 228 (p->p_flag2 & P2_TRAPCAP) != 0) && IN_CAPABILITY_MODE(td)) { 229 ksiginfo_init_trap(&ksi); 230 ksi.ksi_signo = SIGTRAP; 231 ksi.ksi_errno = td->td_errno; 232 ksi.ksi_code = TRAP_CAP; 233 trapsignal(td, &ksi); 234 } 235 } 236 237 /* 238 * Handle reschedule and other end-of-syscall issues 239 */ 240 userret(td, td->td_frame); 241 242 #ifdef KTRACE 243 if (KTRPOINT(td, KTR_SYSRET)) { 244 ktrsysret(sa->code, td->td_errno, td->td_retval[0]); 245 } 246 #endif 247 248 traced = 0; 249 if (__predict_false(p->p_flag & P_TRACED)) { 250 traced = 1; 251 PROC_LOCK(p); 252 td->td_dbgflags |= TDB_SCX; 253 PROC_UNLOCK(p); 254 } 255 if (__predict_false(traced || 256 (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0)) { 257 PROC_LOCK(p); 258 /* 259 * If tracing the execed process, trap to the debugger 260 * so that breakpoints can be set before the program 261 * executes. If debugger requested tracing of syscall 262 * returns, do it now too. 263 */ 264 if (traced && 265 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 || 266 (p->p_ptevents & PTRACE_SCX) != 0)) 267 ptracestop(td, SIGTRAP, NULL); 268 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK); 269 PROC_UNLOCK(p); 270 } 271 272 if (__predict_false(td->td_pflags & TDP_RFPPWAIT)) 273 fork_rfppwait(td); 274 }
Cache object: bfcb46a176e061ca96515665a8407375
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