jim-signal.c

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