1 /* 2 ** 2011 March 28 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** 13 ** The code in this file implements a Tcl interface used to test error 14 ** handling in the os_unix.c module. Wrapper functions that support fault 15 ** injection are registered as the low-level OS functions using the 16 ** xSetSystemCall() method of the VFS. The Tcl interface is as follows: 17 ** 18 ** 19 ** test_syscall install LIST 20 ** Install wrapper functions for all system calls in argument LIST. 21 ** LIST must be a list consisting of zero or more of the following 22 ** literal values: 23 ** 24 ** open close access getcwd stat fstat 25 ** ftruncate fcntl read pread pread64 write 26 ** pwrite pwrite64 fchmod fallocate 27 ** 28 ** test_syscall uninstall 29 ** Uninstall all wrapper functions. 30 ** 31 ** test_syscall fault ?COUNT PERSIST? 32 ** If [test_syscall fault] is invoked without the two arguments, fault 33 ** injection is disabled. Otherwise, fault injection is configured to 34 ** cause a failure on the COUNT'th next call to a system call with a 35 ** wrapper function installed. A COUNT value of 1 means fail the next 36 ** system call. 37 ** 38 ** Argument PERSIST is interpreted as a boolean. If true, the all 39 ** system calls following the initial failure also fail. Otherwise, only 40 ** the single transient failure is injected. 41 ** 42 ** test_syscall errno CALL ERRNO 43 ** Set the value that the global "errno" is set to following a fault 44 ** in call CALL. Argument CALL must be one of the system call names 45 ** listed above (under [test_syscall install]). ERRNO is a symbolic 46 ** name (i.e. "EACCES"). Not all errno codes are supported. Add extra 47 ** to the aErrno table in function test_syscall_errno() below as 48 ** required. 49 ** 50 ** test_syscall reset ?SYSTEM-CALL? 51 ** With no argument, this is an alias for the [uninstall] command. However, 52 ** this command uses a VFS call of the form: 53 ** 54 ** xSetSystemCall(pVfs, 0, 0); 55 ** 56 ** To restore the default system calls. The [uninstall] command restores 57 ** each system call individually by calling (i.e.): 58 ** 59 ** xSetSystemCall(pVfs, "open", 0); 60 ** 61 ** With an argument, this command attempts to reset the system call named 62 ** by the parameter using the same method as [uninstall]. 63 ** 64 ** test_syscall exists SYSTEM-CALL 65 ** Return true if the named system call exists. Or false otherwise. 66 ** 67 ** test_syscall list 68 ** Return a list of all system calls. The list is constructed using 69 ** the xNextSystemCall() VFS method. 70 */ 71 72 #include "sqlite3.h" 73 #include "tcl.h" 74 #include <stdlib.h> 75 #include <string.h> 76 #include <assert.h> 77 78 #ifdef SQLITE_OS_UNIX 79 80 /* From test1.c */ 81 extern const char *sqlite3TestErrorName(int); 82 83 #include <sys/types.h> 84 #include <errno.h> 85 86 static struct TestSyscallGlobal { 87 int bPersist; /* 1 for persistent errors, 0 for transient */ 88 int nCount; /* Fail after this many more calls */ 89 int nFail; /* Number of failures that have occurred */ 90 } gSyscall = { 0, 0 }; 91 92 static int ts_open(const char *, int, int); 93 static int ts_close(int fd); 94 static int ts_access(const char *zPath, int mode); 95 static char *ts_getcwd(char *zPath, size_t nPath); 96 static int ts_stat(const char *zPath, struct stat *p); 97 static int ts_fstat(int fd, struct stat *p); 98 static int ts_ftruncate(int fd, off_t n); 99 static int ts_fcntl(int fd, int cmd, ... ); 100 static int ts_read(int fd, void *aBuf, size_t nBuf); 101 static int ts_pread(int fd, void *aBuf, size_t nBuf, off_t off); 102 static int ts_pread64(int fd, void *aBuf, size_t nBuf, off_t off); 103 static int ts_write(int fd, const void *aBuf, size_t nBuf); 104 static int ts_pwrite(int fd, const void *aBuf, size_t nBuf, off_t off); 105 static int ts_pwrite64(int fd, const void *aBuf, size_t nBuf, off_t off); 106 static int ts_fchmod(int fd, mode_t mode); 107 static int ts_fallocate(int fd, off_t off, off_t len); 108 109 110 struct TestSyscallArray { 111 const char *zName; 112 sqlite3_syscall_ptr xTest; 113 sqlite3_syscall_ptr xOrig; 114 int default_errno; /* Default value for errno following errors */ 115 int custom_errno; /* Current value for errno if error */ 116 } aSyscall[] = { 117 /* 0 */ { "open", (sqlite3_syscall_ptr)ts_open, 0, EACCES, 0 }, 118 /* 1 */ { "close", (sqlite3_syscall_ptr)ts_close, 0, 0, 0 }, 119 /* 2 */ { "access", (sqlite3_syscall_ptr)ts_access, 0, 0, 0 }, 120 /* 3 */ { "getcwd", (sqlite3_syscall_ptr)ts_getcwd, 0, 0, 0 }, 121 /* 4 */ { "stat", (sqlite3_syscall_ptr)ts_stat, 0, 0, 0 }, 122 /* 5 */ { "fstat", (sqlite3_syscall_ptr)ts_fstat, 0, 0, 0 }, 123 /* 6 */ { "ftruncate", (sqlite3_syscall_ptr)ts_ftruncate, 0, 0, 0 }, 124 /* 7 */ { "fcntl", (sqlite3_syscall_ptr)ts_fcntl, 0, 0, 0 }, 125 /* 8 */ { "read", (sqlite3_syscall_ptr)ts_read, 0, 0, 0 }, 126 /* 9 */ { "pread", (sqlite3_syscall_ptr)ts_pread, 0, 0, 0 }, 127 /* 10 */ { "pread64", (sqlite3_syscall_ptr)ts_pread64, 0, 0, 0 }, 128 /* 11 */ { "write", (sqlite3_syscall_ptr)ts_write, 0, 0, 0 }, 129 /* 12 */ { "pwrite", (sqlite3_syscall_ptr)ts_pwrite, 0, 0, 0 }, 130 /* 13 */ { "pwrite64", (sqlite3_syscall_ptr)ts_pwrite64, 0, 0, 0 }, 131 /* 14 */ { "fchmod", (sqlite3_syscall_ptr)ts_fchmod, 0, 0, 0 }, 132 /* 15 */ { "fallocate", (sqlite3_syscall_ptr)ts_fallocate, 0, 0, 0 }, 133 { 0, 0, 0, 0, 0 } 134 }; 135 136 #define orig_open ((int(*)(const char *, int, int))aSyscall[0].xOrig) 137 #define orig_close ((int(*)(int))aSyscall[1].xOrig) 138 #define orig_access ((int(*)(const char*,int))aSyscall[2].xOrig) 139 #define orig_getcwd ((char*(*)(char*,size_t))aSyscall[3].xOrig) 140 #define orig_stat ((int(*)(const char*,struct stat*))aSyscall[4].xOrig) 141 #define orig_fstat ((int(*)(int,struct stat*))aSyscall[5].xOrig) 142 #define orig_ftruncate ((int(*)(int,off_t))aSyscall[6].xOrig) 143 #define orig_fcntl ((int(*)(int,int,...))aSyscall[7].xOrig) 144 #define orig_read ((ssize_t(*)(int,void*,size_t))aSyscall[8].xOrig) 145 #define orig_pread ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[9].xOrig) 146 #define orig_pread64 ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[10].xOrig) 147 #define orig_write ((ssize_t(*)(int,const void*,size_t))aSyscall[11].xOrig) 148 #define orig_pwrite ((ssize_t(*)(int,const void*,size_t,off_t))\ 149 aSyscall[12].xOrig) 150 #define orig_pwrite64 ((ssize_t(*)(int,const void*,size_t,off_t))\ 151 aSyscall[13].xOrig) 152 #define orig_fchmod ((int(*)(int,mode_t))aSyscall[14].xOrig) 153 #define orig_fallocate ((int(*)(int,off_t,off_t))aSyscall[15].xOrig) 154 155 156 /* 157 ** This function is called exactly once from within each invocation of a 158 ** system call wrapper in this file. It returns 1 if the function should 159 ** fail, or 0 if it should succeed. 160 */ 161 static int tsIsFail(void){ 162 gSyscall.nCount--; 163 if( gSyscall.nCount==0 || (gSyscall.nFail && gSyscall.bPersist) ){ 164 gSyscall.nFail++; 165 return 1; 166 } 167 return 0; 168 } 169 170 /* 171 ** Return the current error-number value for function zFunc. zFunc must be 172 ** the name of a system call in the aSyscall[] table. 173 ** 174 ** Usually, the current error-number is the value that errno should be set 175 ** to if the named system call fails. The exception is "fallocate". See 176 ** comments above the implementation of ts_fallocate() for details. 177 */ 178 static int tsErrno(const char *zFunc){ 179 int i; 180 int nFunc = strlen(zFunc); 181 for(i=0; aSyscall[i].zName; i++){ 182 if( strlen(aSyscall[i].zName)!=nFunc ) continue; 183 if( memcmp(aSyscall[i].zName, zFunc, nFunc) ) continue; 184 return aSyscall[i].custom_errno; 185 } 186 187 assert(0); 188 return 0; 189 } 190 191 /* 192 ** A wrapper around tsIsFail(). If tsIsFail() returns non-zero, set the 193 ** value of errno before returning. 194 */ 195 static int tsIsFailErrno(const char *zFunc){ 196 if( tsIsFail() ){ 197 errno = tsErrno(zFunc); 198 return 1; 199 } 200 return 0; 201 } 202 203 /* 204 ** A wrapper around open(). 205 */ 206 static int ts_open(const char *zFile, int flags, int mode){ 207 if( tsIsFailErrno("open") ){ 208 return -1; 209 } 210 return orig_open(zFile, flags, mode); 211 } 212 213 /* 214 ** A wrapper around close(). 215 */ 216 static int ts_close(int fd){ 217 if( tsIsFail() ){ 218 return -1; 219 } 220 return orig_close(fd); 221 } 222 223 /* 224 ** A wrapper around access(). 225 */ 226 static int ts_access(const char *zPath, int mode){ 227 if( tsIsFail() ){ 228 return -1; 229 } 230 return orig_access(zPath, mode); 231 } 232 233 /* 234 ** A wrapper around getcwd(). 235 */ 236 static char *ts_getcwd(char *zPath, size_t nPath){ 237 if( tsIsFail() ){ 238 return NULL; 239 } 240 return orig_getcwd(zPath, nPath); 241 } 242 243 /* 244 ** A wrapper around stat(). 245 */ 246 static int ts_stat(const char *zPath, struct stat *p){ 247 if( tsIsFail() ){ 248 return -1; 249 } 250 return orig_stat(zPath, p); 251 } 252 253 /* 254 ** A wrapper around fstat(). 255 */ 256 static int ts_fstat(int fd, struct stat *p){ 257 if( tsIsFail() ){ 258 return -1; 259 } 260 return orig_fstat(fd, p); 261 } 262 263 /* 264 ** A wrapper around ftruncate(). 265 */ 266 static int ts_ftruncate(int fd, off_t n){ 267 if( tsIsFail() ){ 268 return -1; 269 } 270 return orig_ftruncate(fd, n); 271 } 272 273 /* 274 ** A wrapper around fcntl(). 275 */ 276 static int ts_fcntl(int fd, int cmd, ... ){ 277 va_list ap; 278 void *pArg; 279 if( tsIsFail() ){ 280 return -1; 281 } 282 va_start(ap, cmd); 283 pArg = va_arg(ap, void *); 284 return orig_fcntl(fd, cmd, pArg); 285 } 286 287 /* 288 ** A wrapper around read(). 289 */ 290 static int ts_read(int fd, void *aBuf, size_t nBuf){ 291 if( tsIsFail() ){ 292 return -1; 293 } 294 return orig_read(fd, aBuf, nBuf); 295 } 296 297 /* 298 ** A wrapper around pread(). 299 */ 300 static int ts_pread(int fd, void *aBuf, size_t nBuf, off_t off){ 301 if( tsIsFail() ){ 302 return -1; 303 } 304 return orig_pread(fd, aBuf, nBuf, off); 305 } 306 307 /* 308 ** A wrapper around pread64(). 309 */ 310 static int ts_pread64(int fd, void *aBuf, size_t nBuf, off_t off){ 311 if( tsIsFail() ){ 312 return -1; 313 } 314 return orig_pread64(fd, aBuf, nBuf, off); 315 } 316 317 /* 318 ** A wrapper around write(). 319 */ 320 static int ts_write(int fd, const void *aBuf, size_t nBuf){ 321 if( tsIsFail() ){ 322 return -1; 323 } 324 return orig_write(fd, aBuf, nBuf); 325 } 326 327 /* 328 ** A wrapper around pwrite(). 329 */ 330 static int ts_pwrite(int fd, const void *aBuf, size_t nBuf, off_t off){ 331 if( tsIsFail() ){ 332 return -1; 333 } 334 return orig_pwrite(fd, aBuf, nBuf, off); 335 } 336 337 /* 338 ** A wrapper around pwrite64(). 339 */ 340 static int ts_pwrite64(int fd, const void *aBuf, size_t nBuf, off_t off){ 341 if( tsIsFail() ){ 342 return -1; 343 } 344 return orig_pwrite64(fd, aBuf, nBuf, off); 345 } 346 347 /* 348 ** A wrapper around fchmod(). 349 */ 350 static int ts_fchmod(int fd, mode_t mode){ 351 if( tsIsFail() ){ 352 return -1; 353 } 354 return orig_fchmod(fd, mode); 355 } 356 357 /* 358 ** A wrapper around fallocate(). 359 ** 360 ** SQLite assumes that the fallocate() function is compatible with 361 ** posix_fallocate(). According to the Linux man page (2009-09-30): 362 ** 363 ** posix_fallocate() returns zero on success, or an error number on 364 ** failure. Note that errno is not set. 365 */ 366 static int ts_fallocate(int fd, off_t off, off_t len){ 367 if( tsIsFail() ){ 368 return tsErrno("fallocate"); 369 } 370 return orig_fallocate(fd, off, len); 371 } 372 373 static int test_syscall_install( 374 void * clientData, 375 Tcl_Interp *interp, 376 int objc, 377 Tcl_Obj *CONST objv[] 378 ){ 379 sqlite3_vfs *pVfs; 380 int nElem; 381 int i; 382 Tcl_Obj **apElem; 383 384 if( objc!=3 ){ 385 Tcl_WrongNumArgs(interp, 2, objv, "SYSCALL-LIST"); 386 return TCL_ERROR; 387 } 388 if( Tcl_ListObjGetElements(interp, objv[2], &nElem, &apElem) ){ 389 return TCL_ERROR; 390 } 391 pVfs = sqlite3_vfs_find(0); 392 393 for(i=0; i<nElem; i++){ 394 int iCall; 395 int rc = Tcl_GetIndexFromObjStruct(interp, 396 apElem[i], aSyscall, sizeof(aSyscall[0]), "system-call", 0, &iCall 397 ); 398 if( rc ) return rc; 399 if( aSyscall[iCall].xOrig==0 ){ 400 aSyscall[iCall].xOrig = pVfs->xGetSystemCall(pVfs, aSyscall[iCall].zName); 401 pVfs->xSetSystemCall(pVfs, aSyscall[iCall].zName, aSyscall[iCall].xTest); 402 } 403 aSyscall[iCall].custom_errno = aSyscall[iCall].default_errno; 404 } 405 406 return TCL_OK; 407 } 408 409 static int test_syscall_uninstall( 410 void * clientData, 411 Tcl_Interp *interp, 412 int objc, 413 Tcl_Obj *CONST objv[] 414 ){ 415 sqlite3_vfs *pVfs; 416 int i; 417 418 if( objc!=2 ){ 419 Tcl_WrongNumArgs(interp, 2, objv, ""); 420 return TCL_ERROR; 421 } 422 423 pVfs = sqlite3_vfs_find(0); 424 for(i=0; aSyscall[i].zName; i++){ 425 if( aSyscall[i].xOrig ){ 426 pVfs->xSetSystemCall(pVfs, aSyscall[i].zName, 0); 427 aSyscall[i].xOrig = 0; 428 } 429 } 430 return TCL_OK; 431 } 432 433 static int test_syscall_reset( 434 void * clientData, 435 Tcl_Interp *interp, 436 int objc, 437 Tcl_Obj *CONST objv[] 438 ){ 439 sqlite3_vfs *pVfs; 440 int i; 441 int rc; 442 443 if( objc!=2 && objc!=3 ){ 444 Tcl_WrongNumArgs(interp, 2, objv, ""); 445 return TCL_ERROR; 446 } 447 448 pVfs = sqlite3_vfs_find(0); 449 if( objc==2 ){ 450 rc = pVfs->xSetSystemCall(pVfs, 0, 0); 451 for(i=0; aSyscall[i].zName; i++) aSyscall[i].xOrig = 0; 452 }else{ 453 int nFunc; 454 char *zFunc = Tcl_GetStringFromObj(objv[2], &nFunc); 455 rc = pVfs->xSetSystemCall(pVfs, Tcl_GetString(objv[2]), 0); 456 for(i=0; rc==SQLITE_OK && aSyscall[i].zName; i++){ 457 if( strlen(aSyscall[i].zName)!=nFunc ) continue; 458 if( memcmp(aSyscall[i].zName, zFunc, nFunc) ) continue; 459 aSyscall[i].xOrig = 0; 460 } 461 } 462 if( rc!=SQLITE_OK ){ 463 Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3TestErrorName(rc), -1)); 464 return TCL_ERROR; 465 } 466 467 Tcl_ResetResult(interp); 468 return TCL_OK; 469 } 470 471 static int test_syscall_exists( 472 void * clientData, 473 Tcl_Interp *interp, 474 int objc, 475 Tcl_Obj *CONST objv[] 476 ){ 477 sqlite3_vfs *pVfs; 478 sqlite3_syscall_ptr x; 479 480 if( objc!=3 ){ 481 Tcl_WrongNumArgs(interp, 2, objv, ""); 482 return TCL_ERROR; 483 } 484 485 pVfs = sqlite3_vfs_find(0); 486 x = pVfs->xGetSystemCall(pVfs, Tcl_GetString(objv[2])); 487 488 Tcl_SetObjResult(interp, Tcl_NewBooleanObj(x!=0)); 489 return TCL_OK; 490 } 491 492 static int test_syscall_fault( 493 void * clientData, 494 Tcl_Interp *interp, 495 int objc, 496 Tcl_Obj *CONST objv[] 497 ){ 498 int nCount = 0; 499 int bPersist = 0; 500 501 if( objc!=2 && objc!=4 ){ 502 Tcl_WrongNumArgs(interp, 2, objv, "?COUNT PERSIST?"); 503 return TCL_ERROR; 504 } 505 506 if( objc==4 ){ 507 if( Tcl_GetIntFromObj(interp, objv[2], &nCount) 508 || Tcl_GetBooleanFromObj(interp, objv[3], &bPersist) 509 ){ 510 return TCL_ERROR; 511 } 512 } 513 514 Tcl_SetObjResult(interp, Tcl_NewIntObj(gSyscall.nFail)); 515 gSyscall.nCount = nCount; 516 gSyscall.bPersist = bPersist; 517 gSyscall.nFail = 0; 518 return TCL_OK; 519 } 520 521 static int test_syscall_errno( 522 void * clientData, 523 Tcl_Interp *interp, 524 int objc, 525 Tcl_Obj *CONST objv[] 526 ){ 527 int iCall; 528 int iErrno; 529 int rc; 530 531 struct Errno { 532 const char *z; 533 int i; 534 } aErrno[] = { 535 { "EACCES", EACCES }, 536 { 0, 0 } 537 }; 538 539 if( objc!=4 ){ 540 Tcl_WrongNumArgs(interp, 2, objv, "SYSCALL ERRNO"); 541 return TCL_ERROR; 542 } 543 544 rc = Tcl_GetIndexFromObjStruct(interp, 545 objv[2], aSyscall, sizeof(aSyscall[0]), "system-call", 0, &iCall 546 ); 547 if( rc!=TCL_OK ) return rc; 548 rc = Tcl_GetIndexFromObjStruct(interp, 549 objv[3], aErrno, sizeof(aErrno[0]), "errno", 0, &iErrno 550 ); 551 if( rc!=TCL_OK ) return rc; 552 553 aSyscall[iCall].custom_errno = aErrno[iErrno].i; 554 return TCL_OK; 555 } 556 557 static int test_syscall_list( 558 void * clientData, 559 Tcl_Interp *interp, 560 int objc, 561 Tcl_Obj *CONST objv[] 562 ){ 563 const char *zSys; 564 sqlite3_vfs *pVfs; 565 Tcl_Obj *pList; 566 567 if( objc!=2 ){ 568 Tcl_WrongNumArgs(interp, 2, objv, ""); 569 return TCL_ERROR; 570 } 571 572 pVfs = sqlite3_vfs_find(0); 573 pList = Tcl_NewObj(); 574 Tcl_IncrRefCount(pList); 575 for(zSys = pVfs->xNextSystemCall(pVfs, 0); 576 zSys!=0; 577 zSys = pVfs->xNextSystemCall(pVfs, zSys) 578 ){ 579 Tcl_ListObjAppendElement(interp, pList, Tcl_NewStringObj(zSys, -1)); 580 } 581 582 Tcl_SetObjResult(interp, pList); 583 Tcl_DecrRefCount(pList); 584 return TCL_OK; 585 } 586 587 static int test_syscall( 588 void * clientData, 589 Tcl_Interp *interp, 590 int objc, 591 Tcl_Obj *CONST objv[] 592 ){ 593 struct SyscallCmd { 594 const char *zName; 595 Tcl_ObjCmdProc *xCmd; 596 } aCmd[] = { 597 { "fault", test_syscall_fault }, 598 { "install", test_syscall_install }, 599 { "uninstall", test_syscall_uninstall }, 600 { "reset", test_syscall_reset }, 601 { "errno", test_syscall_errno }, 602 { "exists", test_syscall_exists }, 603 { "list", test_syscall_list }, 604 { 0, 0 } 605 }; 606 int iCmd; 607 int rc; 608 609 if( objc<2 ){ 610 Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ..."); 611 return TCL_ERROR; 612 } 613 rc = Tcl_GetIndexFromObjStruct(interp, 614 objv[1], aCmd, sizeof(aCmd[0]), "sub-command", 0, &iCmd 615 ); 616 if( rc!=TCL_OK ) return rc; 617 return aCmd[iCmd].xCmd(clientData, interp, objc, objv); 618 } 619 620 int SqlitetestSyscall_Init(Tcl_Interp *interp){ 621 struct SyscallCmd { 622 const char *zName; 623 Tcl_ObjCmdProc *xCmd; 624 } aCmd[] = { 625 { "test_syscall", test_syscall}, 626 }; 627 int i; 628 629 for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){ 630 Tcl_CreateObjCommand(interp, aCmd[i].zName, aCmd[i].xCmd, 0, 0); 631 } 632 return TCL_OK; 633 } 634 #else 635 int SqlitetestSyscall_Init(Tcl_Interp *interp){ 636 return TCL_OK; 637 } 638 #endif 639 640