1 /* $NetBSD: kern_syscall.c,v 1.8 2013/12/09 16:49:43 pooka Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software developed for The NetBSD Foundation 8 * by Andrew Doran. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: kern_syscall.c,v 1.8 2013/12/09 16:49:43 pooka Exp $"); 34 35 #ifdef _KERNEL_OPT 36 #include "opt_modular.h" 37 #include "opt_syscall_debug.h" 38 #include "opt_ktrace.h" 39 #include "opt_ptrace.h" 40 #endif 41 42 /* XXX To get syscall prototypes. */ 43 #define SYSVSHM 44 #define SYSVSEM 45 #define SYSVMSG 46 47 #include <sys/param.h> 48 #include <sys/module.h> 49 #include <sys/sched.h> 50 #include <sys/syscall.h> 51 #include <sys/syscallargs.h> 52 #include <sys/syscallvar.h> 53 #include <sys/systm.h> 54 #include <sys/xcall.h> 55 #include <sys/ktrace.h> 56 #include <sys/ptrace.h> 57 58 int 59 sys_nomodule(struct lwp *l, const void *v, register_t *retval) 60 { 61 #ifdef MODULAR 62 static struct { 63 u_int al_code; 64 const char *al_module; 65 } const autoload[] = { 66 { SYS_aio_cancel, "aio" }, 67 { SYS_aio_error, "aio" }, 68 { SYS_aio_fsync, "aio" }, 69 { SYS_aio_read, "aio" }, 70 { SYS_aio_return, "aio" }, 71 { SYS___aio_suspend50, "aio" }, 72 { SYS_aio_write, "aio" }, 73 { SYS_lio_listio, "aio" }, 74 { SYS_mq_open, "mqueue" }, 75 { SYS_mq_close, "mqueue" }, 76 { SYS_mq_unlink, "mqueue" }, 77 { SYS_mq_getattr, "mqueue" }, 78 { SYS_mq_setattr, "mqueue" }, 79 { SYS_mq_notify, "mqueue" }, 80 { SYS_mq_send, "mqueue" }, 81 { SYS_mq_receive, "mqueue" }, 82 { SYS___mq_timedsend50, "mqueue" }, 83 { SYS___mq_timedreceive50, "mqueue" }, 84 { SYS_compat_43_fstat43, "compat" }, 85 { SYS_compat_43_lstat43, "compat" }, 86 { SYS_compat_43_oaccept, "compat" }, 87 { SYS_compat_43_ocreat, "compat" }, 88 { SYS_compat_43_oftruncate, "compat" }, 89 { SYS_compat_43_ogetdirentries, "compat" }, 90 { SYS_compat_43_ogetdtablesize, "compat" }, 91 { SYS_compat_43_ogethostid, "compat" }, 92 { SYS_compat_43_ogethostname, "compat" }, 93 { SYS_compat_43_ogetkerninfo, "compat" }, 94 { SYS_compat_43_ogetpagesize, "compat" }, 95 { SYS_compat_43_ogetpeername, "compat" }, 96 { SYS_compat_43_ogetrlimit, "compat" }, 97 { SYS_compat_43_ogetsockname, "compat" }, 98 { SYS_compat_43_okillpg, "compat" }, 99 { SYS_compat_43_olseek, "compat" }, 100 { SYS_compat_43_ommap, "compat" }, 101 { SYS_compat_43_oquota, "compat" }, 102 { SYS_compat_43_orecv, "compat" }, 103 { SYS_compat_43_orecvfrom, "compat" }, 104 { SYS_compat_43_orecvmsg, "compat" }, 105 { SYS_compat_43_osend, "compat" }, 106 { SYS_compat_43_osendmsg, "compat" }, 107 { SYS_compat_43_osethostid, "compat" }, 108 { SYS_compat_43_osethostname, "compat" }, 109 { SYS_compat_43_osetrlimit, "compat" }, 110 { SYS_compat_43_osigblock, "compat" }, 111 { SYS_compat_43_osigsetmask, "compat" }, 112 { SYS_compat_43_osigstack, "compat" }, 113 { SYS_compat_43_osigvec, "compat" }, 114 { SYS_compat_43_otruncate, "compat" }, 115 { SYS_compat_43_owait, "compat" }, 116 { SYS_compat_43_stat43, "compat" }, 117 { SYS_compat_09_ogetdomainname, "compat" }, 118 { SYS_compat_09_osetdomainname, "compat" }, 119 { SYS_compat_09_ouname, "compat" }, 120 #ifndef _LP64 121 { SYS_compat_10_omsgsys, "compat" }, 122 { SYS_compat_10_osemsys, "compat" }, 123 { SYS_compat_10_oshmsys, "compat" }, 124 #endif 125 { SYS_compat_12_fstat12, "compat" }, 126 { SYS_compat_12_getdirentries, "compat" }, 127 { SYS_compat_12_lstat12, "compat" }, 128 { SYS_compat_12_msync, "compat" }, 129 { SYS_compat_12_oreboot, "compat" }, 130 { SYS_compat_12_oswapon, "compat" }, 131 { SYS_compat_12_stat12, "compat" }, 132 { SYS_compat_13_sigaction13, "compat" }, 133 { SYS_compat_13_sigaltstack13, "compat" }, 134 { SYS_compat_13_sigpending13, "compat" }, 135 { SYS_compat_13_sigprocmask13, "compat" }, 136 { SYS_compat_13_sigreturn13, "compat" }, 137 { SYS_compat_13_sigsuspend13, "compat" }, 138 { SYS_compat_14___semctl, "compat" }, 139 { SYS_compat_14_msgctl, "compat" }, 140 { SYS_compat_14_shmctl, "compat" }, 141 { SYS_compat_16___sigaction14, "compat" }, 142 { SYS_compat_16___sigreturn14, "compat" }, 143 { SYS_compat_20_fhstatfs, "compat" }, 144 { SYS_compat_20_fstatfs, "compat" }, 145 { SYS_compat_20_getfsstat, "compat" }, 146 { SYS_compat_20_statfs, "compat" }, 147 { SYS_compat_30___fhstat30, "compat" }, 148 { SYS_compat_30___fstat13, "compat" }, 149 { SYS_compat_30___lstat13, "compat" }, 150 { SYS_compat_30___stat13, "compat" }, 151 { SYS_compat_30_fhopen, "compat" }, 152 { SYS_compat_30_fhstat, "compat" }, 153 { SYS_compat_30_fhstatvfs1, "compat" }, 154 { SYS_compat_30_getdents, "compat" }, 155 { SYS_compat_30_getfh, "compat" }, 156 { SYS_compat_30_socket, "compat" }, 157 { SYS_compat_40_mount, "compat" }, 158 { SYS_compat_50_wait4, "compat" }, 159 { SYS_compat_50_mknod, "compat" }, 160 { SYS_compat_50_setitimer, "compat" }, 161 { SYS_compat_50_getitimer, "compat" }, 162 { SYS_compat_50_select, "compat" }, 163 { SYS_compat_50_gettimeofday, "compat" }, 164 { SYS_compat_50_getrusage, "compat" }, 165 { SYS_compat_50_settimeofday, "compat" }, 166 { SYS_compat_50_utimes, "compat" }, 167 { SYS_compat_50_adjtime, "compat" }, 168 { SYS_compat_50_lfs_segwait, "compat" }, 169 { SYS_compat_50_futimes, "compat" }, 170 { SYS_compat_50_clock_gettime, "compat" }, 171 { SYS_compat_50_clock_settime, "compat" }, 172 { SYS_compat_50_clock_getres, "compat" }, 173 { SYS_compat_50_timer_settime, "compat" }, 174 { SYS_compat_50_timer_gettime, "compat" }, 175 { SYS_compat_50_nanosleep, "compat" }, 176 { SYS_compat_50___sigtimedwait, "compat" }, 177 { SYS_compat_50_mq_timedsend, "compat" }, 178 { SYS_compat_50_mq_timedreceive, "compat" }, 179 { SYS_compat_50_lutimes, "compat" }, 180 { SYS_compat_50_____semctl13, "compat" }, 181 { SYS_compat_50___msgctl13, "compat" }, 182 { SYS_compat_50___shmctl13, "compat" }, 183 { SYS_compat_50__lwp_park, "compat" }, 184 { SYS_compat_50_kevent, "compat" }, 185 { SYS_compat_50_pselect, "compat" }, 186 { SYS_compat_50_pollts, "compat" }, 187 { SYS_compat_50___stat30, "compat" }, 188 { SYS_compat_50___fstat30, "compat" }, 189 { SYS_compat_50___lstat30, "compat" }, 190 { SYS_compat_50___ntp_gettime30, "compat" }, 191 { SYS_compat_50___fhstat40, "compat" }, 192 { SYS_compat_50_aio_suspend, "compat" }, 193 { SYS__ksem_init, "ksem" }, 194 { SYS__ksem_open, "ksem" }, 195 { SYS__ksem_unlink, "ksem" }, 196 { SYS__ksem_close, "ksem" }, 197 { SYS__ksem_post, "ksem" }, 198 { SYS__ksem_wait, "ksem" }, 199 { SYS__ksem_trywait, "ksem" }, 200 { SYS__ksem_getvalue, "ksem" }, 201 { SYS__ksem_destroy, "ksem" }, 202 { SYS__ksem_timedwait, "ksem" }, 203 { SYS_nfssvc, "nfsserver" }, 204 { SYS_afssys, "openafs" }, 205 }; 206 const struct sysent *sy; 207 const struct emul *em; 208 int code, i; 209 210 /* 211 * Restart the syscall if we interrupted a module unload that 212 * failed. Acquiring kernconfig_lock delays us until any unload 213 * has been completed or rolled back. 214 */ 215 kernconfig_lock(); 216 sy = l->l_sysent; 217 if (sy->sy_call != sys_nomodule) { 218 kernconfig_unlock(); 219 return ERESTART; 220 } 221 /* 222 * Try to autoload a module to satisfy the request. If it 223 * works, retry the request. 224 */ 225 em = l->l_proc->p_emul; 226 if (em == &emul_netbsd) { 227 code = sy - em->e_sysent; 228 for (i = 0; i < __arraycount(autoload); i++) { 229 if (autoload[i].al_code != code) { 230 continue; 231 } 232 if (module_autoload(autoload[i].al_module, 233 MODULE_CLASS_ANY) != 0 || 234 sy->sy_call == sys_nomodule) { 235 break; 236 } 237 kernconfig_unlock(); 238 return ERESTART; 239 } 240 } 241 kernconfig_unlock(); 242 #endif /* MODULAR */ 243 244 return sys_nosys(l, v, retval); 245 } 246 247 int 248 syscall_establish(const struct emul *em, const struct syscall_package *sp) 249 { 250 struct sysent *sy; 251 int i; 252 253 KASSERT(kernconfig_is_held()); 254 255 if (em == NULL) { 256 em = &emul_netbsd; 257 } 258 sy = em->e_sysent; 259 260 /* 261 * Ensure that all preconditions are valid, since this is 262 * an all or nothing deal. Once a system call is entered, 263 * it can become busy and we could be unable to remove it 264 * on error. 265 */ 266 for (i = 0; sp[i].sp_call != NULL; i++) { 267 if (sy[sp[i].sp_code].sy_call != sys_nomodule) { 268 #ifdef DIAGNOSTIC 269 printf("syscall %d is busy\n", sp[i].sp_code); 270 #endif 271 return EBUSY; 272 } 273 } 274 /* Everything looks good, patch them in. */ 275 for (i = 0; sp[i].sp_call != NULL; i++) { 276 sy[sp[i].sp_code].sy_call = sp[i].sp_call; 277 } 278 279 return 0; 280 } 281 282 int 283 syscall_disestablish(const struct emul *em, const struct syscall_package *sp) 284 { 285 struct sysent *sy; 286 uint64_t where; 287 lwp_t *l; 288 int i; 289 290 KASSERT(kernconfig_is_held()); 291 292 if (em == NULL) { 293 em = &emul_netbsd; 294 } 295 sy = em->e_sysent; 296 297 /* 298 * First, patch the system calls to sys_nomodule to gate further 299 * activity. 300 */ 301 for (i = 0; sp[i].sp_call != NULL; i++) { 302 KASSERT(sy[sp[i].sp_code].sy_call == sp[i].sp_call); 303 sy[sp[i].sp_code].sy_call = sys_nomodule; 304 } 305 306 /* 307 * Run a cross call to cycle through all CPUs. This does two 308 * things: lock activity provides a barrier and makes our update 309 * of sy_call visible to all CPUs, and upon return we can be sure 310 * that we see pertinent values of l_sysent posted by remote CPUs. 311 */ 312 where = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL); 313 xc_wait(where); 314 315 /* 316 * Now it's safe to check l_sysent. Run through all LWPs and see 317 * if anyone is still using the system call. 318 */ 319 for (i = 0; sp[i].sp_call != NULL; i++) { 320 mutex_enter(proc_lock); 321 LIST_FOREACH(l, &alllwp, l_list) { 322 if (l->l_sysent == &sy[sp[i].sp_code]) { 323 break; 324 } 325 } 326 mutex_exit(proc_lock); 327 if (l == NULL) { 328 continue; 329 } 330 /* 331 * We lose: one or more calls are still in use. Put back 332 * the old entrypoints and act like nothing happened. 333 * When we drop kernconfig_lock, any system calls held in 334 * sys_nomodule() will be restarted. 335 */ 336 for (i = 0; sp[i].sp_call != NULL; i++) { 337 sy[sp[i].sp_code].sy_call = sp[i].sp_call; 338 } 339 return EBUSY; 340 } 341 342 return 0; 343 } 344 345 /* 346 * Return true if system call tracing is enabled for the specified process. 347 */ 348 bool 349 trace_is_enabled(struct proc *p) 350 { 351 #ifdef SYSCALL_DEBUG 352 return (true); 353 #endif 354 #ifdef KTRACE 355 if (ISSET(p->p_traceflag, (KTRFAC_SYSCALL | KTRFAC_SYSRET))) 356 return (true); 357 #endif 358 #ifdef PTRACE 359 if (ISSET(p->p_slflag, PSL_SYSCALL)) 360 return (true); 361 #endif 362 363 return (false); 364 } 365 366 /* 367 * Start trace of particular system call. If process is being traced, 368 * this routine is called by MD syscall dispatch code just before 369 * a system call is actually executed. 370 */ 371 int 372 trace_enter(register_t code, const register_t *args, int narg) 373 { 374 int error = 0; 375 376 #ifdef SYSCALL_DEBUG 377 scdebug_call(code, args); 378 #endif /* SYSCALL_DEBUG */ 379 380 ktrsyscall(code, args, narg); 381 382 #ifdef PTRACE 383 if ((curlwp->l_proc->p_slflag & (PSL_SYSCALL|PSL_TRACED)) == 384 (PSL_SYSCALL|PSL_TRACED)) { 385 process_stoptrace(); 386 if (curlwp->l_proc->p_slflag & PSL_SYSCALLEMU) { 387 /* tracer will emulate syscall for us */ 388 error = EJUSTRETURN; 389 } 390 } 391 #endif 392 return error; 393 } 394 395 /* 396 * End trace of particular system call. If process is being traced, 397 * this routine is called by MD syscall dispatch code just after 398 * a system call finishes. 399 * MD caller guarantees the passed 'code' is within the supported 400 * system call number range for emulation the process runs under. 401 */ 402 void 403 trace_exit(register_t code, register_t rval[], int error) 404 { 405 #ifdef PTRACE 406 struct proc *p = curlwp->l_proc; 407 #endif 408 409 #ifdef SYSCALL_DEBUG 410 scdebug_ret(code, error, rval); 411 #endif /* SYSCALL_DEBUG */ 412 413 ktrsysret(code, error, rval); 414 415 #ifdef PTRACE 416 if ((p->p_slflag & (PSL_SYSCALL|PSL_TRACED|PSL_SYSCALLEMU)) == 417 (PSL_SYSCALL|PSL_TRACED)) 418 process_stoptrace(); 419 CLR(p->p_slflag, PSL_SYSCALLEMU); 420 #endif 421 } 422