jim-signal.c

   1 /*
   2  * jim-signal.c
   3  *
   4  */
   5
   6 #include <signal.h>
   7 #include <string.h>
   8 #include <ctype.h>
   9
  10 #include "jimautoconf.h"
  11 #ifdef HAVE_UNISTD_H
  12     #include <unistd.h>
  13 #endif
  14 #include <jim-subcmd.h>
  15 #include <jim-signal.h>
  16
  17 #define MAX_SIGNALS_WIDE (sizeof(jim_wide) * 8)
  18 #if defined(NSIG)
  19     #define MAX_SIGNALS (int)((NSIG < MAX_SIGNALS_WIDE) ? NSIG : MAX_SIGNALS_WIDE)
  20 #else
  21     #define MAX_SIGNALS (int)MAX_SIGNALS_WIDE
  22 #endif
  23
  24 static jim_wide *sigloc;
  25 static jim_wide sigsblocked;
  26 static struct sigaction *sa_old;
  27 static struct {
  28     int status;
  29     const char *name;
  30 } siginfo[MAX_SIGNALS];
  31
  32 /* Make sure to do this as a wide, not int */
  33 #define sig_to_bit(SIG) ((jim_wide)1 << (SIG))
  34
  35 static void signal_handler(int sig)
  36 {
  37     /* We just remember which signals occurred. Jim_Eval() will
  38      * notice this as soon as it can and throw an error
  39      */
  40     *sigloc |= sig_to_bit(sig);
  41 }
  42
  43 static void signal_ignorer(int sig)
  44 {
  45     /* We just remember which signals occurred */
  46     sigsblocked |= sig_to_bit(sig);
  47 }
  48
  49 static void signal_init_names(void)
  50 {
  51 #define SET_SIG_NAME(SIG) siginfo[SIG].name = #SIG
  52
  53     SET_SIG_NAME(SIGABRT);
  54     SET_SIG_NAME(SIGALRM);
  55     SET_SIG_NAME(SIGBUS);
  56     SET_SIG_NAME(SIGCHLD);
  57     SET_SIG_NAME(SIGCONT);
  58     SET_SIG_NAME(SIGFPE);
  59     SET_SIG_NAME(SIGHUP);
  60     SET_SIG_NAME(SIGILL);
  61     SET_SIG_NAME(SIGINT);
  62 #ifdef SIGIO
  63     SET_SIG_NAME(SIGIO);
  64 #endif
  65     SET_SIG_NAME(SIGKILL);
  66     SET_SIG_NAME(SIGPIPE);
  67     SET_SIG_NAME(SIGPROF);
  68     SET_SIG_NAME(SIGQUIT);
  69     SET_SIG_NAME(SIGSEGV);
  70     SET_SIG_NAME(SIGSTOP);
  71     SET_SIG_NAME(SIGSYS);
  72     SET_SIG_NAME(SIGTERM);
  73     SET_SIG_NAME(SIGTRAP);
  74     SET_SIG_NAME(SIGTSTP);
  75     SET_SIG_NAME(SIGTTIN);
  76     SET_SIG_NAME(SIGTTOU);
  77     SET_SIG_NAME(SIGURG);
  78     SET_SIG_NAME(SIGUSR1);
  79     SET_SIG_NAME(SIGUSR2);
  80     SET_SIG_NAME(SIGVTALRM);
  81     SET_SIG_NAME(SIGWINCH);
  82     SET_SIG_NAME(SIGXCPU);
  83     SET_SIG_NAME(SIGXFSZ);
  84 #ifdef SIGPWR
  85     SET_SIG_NAME(SIGPWR);
  86 #endif
  87 #ifdef SIGCLD
  88     SET_SIG_NAME(SIGCLD);
  89 #endif
  90 #ifdef SIGEMT
  91     SET_SIG_NAME(SIGEMT);
  92 #endif
  93 #ifdef SIGLOST
  94     SET_SIG_NAME(SIGLOST);
  95 #endif
  96 #ifdef SIGPOLL
  97     SET_SIG_NAME(SIGPOLL);
  98 #endif
  99 #ifdef SIGINFO
 100     SET_SIG_NAME(SIGINFO);
 101 #endif
 102 }
 103
 104 /*
 105  *----------------------------------------------------------------------
 106  *
 107  * Tcl_SignalId --
 108  *
 109  *      Return a textual identifier for a signal number.
 110  *
 111  * Results:
 112  *      This procedure returns a machine-readable textual identifier
 113  *      that corresponds to sig.  The identifier is the same as the
 114  *      #define name in signal.h.
 115  *
 116  * Side effects:
 117  *      None.
 118  *
 119  *----------------------------------------------------------------------
 120  */
 121 const char *Jim_SignalId(int sig)
 122 {
 123     if (sig >=0 && sig < MAX_SIGNALS) {
 124         if (siginfo[sig].name) {
 125             return siginfo[sig].name;
 126         }
 127     }
 128     return "unknown signal";
 129 }
 130
 131 /**
 132  * Given the name of a signal, returns the signal value if found,
 133  * or returns -1 (and sets an error) if not found.
 134  * We accept -SIGINT, SIGINT, INT or any lowercase version or a number,
 135  * either positive or negative.
 136  */
 137 static int find_signal_by_name(Jim_Interp *interp, const char *name)
 138 {
 139     int i;
 140     const char *pt = name;
 141
 142     /* Remove optional - and SIG from the front of the name */
 143     if (*pt == '-') {
 144         pt++;
 145     }
 146     if (strncasecmp(name, "sig", 3) == 0) {
 147         pt += 3;
 148     }
 149     if (isdigit(UCHAR(pt[0]))) {
 150         i = atoi(pt);
 151         if (i > 0 && i < MAX_SIGNALS) {
 152             return i;
 153         }
 154     }
 155     else {
 156         for (i = 1; i < MAX_SIGNALS; i++) {
 157             /* Jim_SignalId() returns names such as SIGINT, and
 158              * returns "unknown signal" if unknown, so this will work
 159              */
 160             if (strcasecmp(Jim_SignalId(i) + 3, pt) == 0) {
 161                 return i;
 162             }
 163         }
 164     }
 165     Jim_SetResultFormatted(interp, "unknown signal %s", name);
 166
 167     return -1;
 168 }
 169
 170 #define SIGNAL_ACTION_HANDLE 1
 171 #define SIGNAL_ACTION_IGNORE -1
 172 #define SIGNAL_ACTION_DEFAULT 0
 173
 174 static int do_signal_cmd(Jim_Interp *interp, int action, int argc, Jim_Obj *const *argv)
 175 {
 176     struct sigaction sa;
 177     int i;
 178
 179     if (argc == 0) {
 180         Jim_SetResult(interp, Jim_NewListObj(interp, NULL, 0));
 181         for (i = 1; i < MAX_SIGNALS; i++) {
 182             if (siginfo[i].status == action) {
 183                 /* Add signal name to the list  */
 184                 Jim_ListAppendElement(interp, Jim_GetResult(interp),
 185                     Jim_NewStringObj(interp, Jim_SignalId(i), -1));
 186             }
 187         }
 188         return JIM_OK;
 189     }
 190
 191     /* Catch all the signals we care about */
 192     if (action != SIGNAL_ACTION_DEFAULT) {
 193         memset(&sa, 0, sizeof(sa));
 194         if (action == SIGNAL_ACTION_HANDLE) {
 195             sa.sa_handler = signal_handler;
 196         }
 197         else {
 198             sa.sa_handler = signal_ignorer;
 199         }
 200     }
 201
 202     /* Iterate through the provided signals */
 203     for (i = 0; i < argc; i++) {
 204         int sig = find_signal_by_name(interp, Jim_String(argv[i]));
 205
 206         if (sig < 0) {
 207             return JIM_ERR;
 208         }
 209         if (action != siginfo[sig].status) {
 210             /* Need to change the action for this signal */
 211             switch (action) {
 212                 case SIGNAL_ACTION_HANDLE:
 213                 case SIGNAL_ACTION_IGNORE:
 214                     if (siginfo[sig].status == SIGNAL_ACTION_DEFAULT) {
 215                         if (!sa_old) {
 216                             /* Allocate the structure the first time through */
 217                             sa_old = Jim_Alloc(sizeof(*sa_old) * MAX_SIGNALS);
 218                         }
 219                         sigaction(sig, &sa, &sa_old[sig]);
 220                     }
 221                     else {
 222                         sigaction(sig, &sa, 0);
 223                     }
 224                     break;
 225
 226                 case SIGNAL_ACTION_DEFAULT:
 227                     /* Restore old handler */
 228                     if (sa_old) {
 229                         sigaction(sig, &sa_old[sig], 0);
 230                     }
 231             }
 232             siginfo[sig].status = action;
 233         }
 234     }
 235
 236     return JIM_OK;
 237 }
 238
 239 static int signal_cmd_handle(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 240 {
 241     return do_signal_cmd(interp, SIGNAL_ACTION_HANDLE, argc, argv);
 242 }
 243
 244 static int signal_cmd_ignore(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 245 {
 246     return do_signal_cmd(interp, SIGNAL_ACTION_IGNORE, argc, argv);
 247 }
 248
 249 static int signal_cmd_default(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 250 {
 251     return do_signal_cmd(interp, SIGNAL_ACTION_DEFAULT, argc, argv);
 252 }
 253
 254 static int signal_set_sigmask_result(Jim_Interp *interp, jim_wide sigmask)
 255 {
 256     int i;
 257     Jim_Obj *listObj = Jim_NewListObj(interp, NULL, 0);
 258
 259     for (i = 0; i < MAX_SIGNALS; i++) {
 260         if (sigmask & sig_to_bit(i)) {
 261             Jim_ListAppendElement(interp, listObj, Jim_NewStringObj(interp, Jim_SignalId(i), -1));
 262         }
 263     }
 264     Jim_SetResult(interp, listObj);
 265     return JIM_OK;
 266 }
 267
 268 static int signal_cmd_check(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 269 {
 270     int clear = 0;
 271     jim_wide mask = 0;
 272     jim_wide blocked;
 273
 274     if (argc > 0 && Jim_CompareStringImmediate(interp, argv[0], "-clear")) {
 275         clear++;
 276     }
 277     if (argc > clear) {
 278         int i;
 279
 280         /* Signals specified */
 281         for (i = clear; i < argc; i++) {
 282             int sig = find_signal_by_name(interp, Jim_String(argv[i]));
 283
 284             if (sig < 0 || sig >= MAX_SIGNALS) {
 285                 return -1;
 286             }
 287             mask |= sig_to_bit(sig);
 288         }
 289     }
 290     else {
 291         /* No signals specified, so check/clear all */
 292         mask = ~mask;
 293     }
 294
 295     if ((sigsblocked & mask) == 0) {
 296         /* No matching signals, so empty result and nothing to do */
 297         return JIM_OK;
 298     }
 299     /* Be careful we don't have a race condition where signals are cleared but not returned */
 300     blocked = sigsblocked & mask;
 301     if (clear) {
 302         sigsblocked &= ~blocked;
 303     }
 304     /* Set the result */
 305     signal_set_sigmask_result(interp, blocked);
 306     return JIM_OK;
 307 }
 308
 309 static int signal_cmd_throw(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 310 {
 311     int sig = SIGINT;
 312
 313     if (argc == 1) {
 314         if ((sig = find_signal_by_name(interp, Jim_String(argv[0]))) < 0) {
 315             return JIM_ERR;
 316         }
 317     }
 318
 319     /* If the signal is ignored (blocked) ... */
 320     if (siginfo[sig].status == SIGNAL_ACTION_IGNORE) {
 321         sigsblocked |= sig_to_bit(sig);
 322         return JIM_OK;
 323     }
 324
 325     /* Just set the signal */
 326     interp->sigmask |= sig_to_bit(sig);
 327
 328     /* Set the canonical name of the signal as the result */
 329     Jim_SetResultString(interp, Jim_SignalId(sig), -1);
 330
 331     /* And simply say we caught the signal */
 332     return JIM_SIGNAL;
 333 }
 334
 335 /*
 336  *-----------------------------------------------------------------------------
 337  *
 338  * Jim_SignalCmd --
 339  *     Implements the TCL signal command:
 340  *         signal handle|ignore|default|throw ?signals ...?
 341  *         signal throw signal
 342  *
 343  *     Specifies which signals are handled by Tcl code.
 344  *     If the one of the given signals is caught, it causes a JIM_SIGNAL
 345  *     exception to be thrown which can be caught by catch.
 346  *
 347  *     Use 'signal ignore' to ignore the signal(s)
 348  *     Use 'signal default' to go back to the default behaviour
 349  *     Use 'signal throw signal' to raise the given signal
 350  *
 351  *     If no arguments are given, returns the list of signals which are being handled
 352  *
 353  * Results:
 354  *      Standard TCL results.
 355  *
 356  *-----------------------------------------------------------------------------
 357  */
 358 static const jim_subcmd_type signal_command_table[] = {
 359     {   "handle",
 360         "?signals ...?",
 361         signal_cmd_handle,
 362         0,
 363         -1,
 364         /* Description: Lists handled signals, or adds to handled signals */
 365     },
 366     {   "ignore",
 367         "?signals ...?",
 368         signal_cmd_ignore,
 369         0,
 370         -1,
 371         /* Description: Lists ignored signals, or adds to ignored signals */
 372     },
 373     {   "default",
 374         "?signals ...?",
 375         signal_cmd_default,
 376         0,
 377         -1,
 378         /* Description: Lists defaulted signals, or adds to defaulted signals */
 379     },
 380     {   "check",
 381         "?-clear? ?signals ...?",
 382         signal_cmd_check,
 383         0,
 384         -1,
 385         /* Description: Returns ignored signals which have occurred, and optionally clearing them */
 386     },
 387     {   "throw",
 388         "?signal?",
 389         signal_cmd_throw,
 390         0,
 391         1,
 392         /* Description: Raises the given signal (default SIGINT) */
 393     },
 394     { NULL }
 395 };
 396
 397 /**
 398  * Restore default signal handling.
 399  */
 400 static void JimSignalCmdDelete(Jim_Interp *interp, void *privData)
 401 {
 402     int i;
 403     if (sa_old) {
 404         for (i = 1; i < MAX_SIGNALS; i++) {
 405             if (siginfo[i].status != SIGNAL_ACTION_DEFAULT) {
 406                 sigaction(i, &sa_old[i], 0);
 407                 siginfo[i].status = SIGNAL_ACTION_DEFAULT;
 408             }
 409         }
 410     }
 411     Jim_Free(sa_old);
 412     sa_old = NULL;
 413     sigloc = NULL;
 414 }
 415
 416 static int Jim_AlarmCmd(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 417 {
 418     int ret;
 419
 420     if (argc != 2) {
 421         Jim_WrongNumArgs(interp, 1, argv, "seconds");
 422         return JIM_ERR;
 423     }
 424     else {
 425 #ifdef HAVE_UALARM
 426         double t;
 427
 428         ret = Jim_GetDouble(interp, argv[1], &t);
 429         if (ret == JIM_OK) {
 430             if (t < 1) {
 431                 ualarm(t * 1e6, 0);
 432             }
 433             else {
 434                 alarm(t);
 435             }
 436         }
 437 #else
 438         long t;
 439
 440         ret = Jim_GetLong(interp, argv[1], &t);
 441         if (ret == JIM_OK) {
 442             alarm(t);
 443         }
 444 #endif
 445     }
 446
 447     return ret;
 448 }
 449
 450 static int Jim_SleepCmd(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 451 {
 452     int ret;
 453
 454     if (argc != 2) {
 455         Jim_WrongNumArgs(interp, 1, argv, "seconds");
 456         return JIM_ERR;
 457     }
 458     else {
 459         double t;
 460
 461         ret = Jim_GetDouble(interp, argv[1], &t);
 462         if (ret == JIM_OK) {
 463 #ifdef HAVE_USLEEP
 464             usleep((int)((t - (int)t) * 1e6));
 465 #endif
 466             sleep(t);
 467         }
 468     }
 469
 470     return ret;
 471 }
 472
 473 static int Jim_KillCmd(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 474 {
 475     int sig;
 476     long pid;
 477     Jim_Obj *pidObj;
 478     const char *signame;
 479
 480     if (argc != 2 && argc != 3) {
 481         Jim_WrongNumArgs(interp, 1, argv, "?SIG|-0? pid");
 482         return JIM_ERR;
 483     }
 484
 485     if (argc == 2) {
 486         sig = SIGTERM;
 487         pidObj = argv[1];
 488     }
 489     else {
 490         signame = Jim_String(argv[1]);
 491         pidObj = argv[2];
 492
 493         /* Special 'kill -0 pid' to determine if a pid exists */
 494         if (strcmp(signame, "-0") == 0 || strcmp(signame, "0") == 0) {
 495             sig = 0;
 496         }
 497         else {
 498             sig = find_signal_by_name(interp, signame);
 499             if (sig < 0) {
 500                 return JIM_ERR;
 501             }
 502         }
 503     }
 504
 505     if (Jim_GetLong(interp, pidObj, &pid) != JIM_OK) {
 506         return JIM_ERR;
 507     }
 508
 509     if (kill(pid, sig) == 0) {
 510         return JIM_OK;
 511     }
 512
 513     Jim_SetResultString(interp, "kill: Failed to deliver signal", -1);
 514     return JIM_ERR;
 515 }
 516
 517 int Jim_signalInit(Jim_Interp *interp)
 518 {
 519     if (Jim_PackageProvide(interp, "signal", "1.0", JIM_ERRMSG))
 520         return JIM_ERR;
 521
 522     Jim_CreateCommand(interp, "alarm", Jim_AlarmCmd, 0, 0);
 523     Jim_CreateCommand(interp, "kill", Jim_KillCmd, 0, 0);
 524     /* Sleep is slightly dubious here */
 525     Jim_CreateCommand(interp, "sleep", Jim_SleepCmd, 0, 0);
 526
 527     /* Teach the jim core how to set a result from a sigmask */
 528     interp->signal_set_result = signal_set_sigmask_result;
 529
 530     /* Currently only the top level interp supports signals */
 531     if (!sigloc) {
 532         signal_init_names();
 533
 534         /* Make sure we know where to store the signals which occur */
 535         sigloc = &interp->sigmask;
 536
 537         Jim_CreateCommand(interp, "signal", Jim_SubCmdProc, (void *)signal_command_table, JimSignalCmdDelete);
 538     }
 539
 540     return JIM_OK;
 541 }