slang/slsignal.c

   1 /*
   2 Copyright (C) 2004, 2005, 2006 John E. Davis
   3
   4 This file is part of the S-Lang Library.
   5
   6 The S-Lang Library is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public License as
   8 published by the Free Software Foundation; either version 2 of the
   9 License, or (at your option) any later version.
  10
  11 The S-Lang Library is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this library; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 USA.
  20 */
  21
  22 #include "slinclud.h"
  23
  24 #include <signal.h>
  25
  26 #ifdef HAVE_SYS_TYPES_H
  27 # include <sys/types.h>
  28 #endif
  29 #ifdef HAVE_SYS_WAIT_H
  30 # include <sys/wait.h>
  31 #endif
  32
  33 #include <errno.h>
  34
  35 #include "slang.h"
  36 #include "_slang.h"
  37
  38 /* Do not trust these environments */
  39 #if defined(__MINGW32__) || defined(AMIGA)
  40 # ifdef SLANG_POSIX_SIGNALS
  41 #  undef SLANG_POSIX_SIGNALS
  42 # endif
  43 #endif
  44
  45 /* This function will cause system calls to be restarted after signal if possible */
  46 SLSig_Fun_Type *SLsignal (int sig, SLSig_Fun_Type *f)
  47 {
  48 #if defined(SLANG_POSIX_SIGNALS)
  49    struct sigaction old_sa, new_sa;
  50
  51 # ifdef SIGALRM
  52    /* We want system calls to be interrupted by SIGALRM. */
  53    if (sig == SIGALRM) return SLsignal_intr (sig, f);
  54 # endif
  55
  56    sigemptyset (&new_sa.sa_mask);
  57    new_sa.sa_handler = f;
  58
  59    new_sa.sa_flags = 0;
  60 # ifdef SA_RESTART
  61    new_sa.sa_flags |= SA_RESTART;
  62 # endif
  63
  64    if (-1 == sigaction (sig, &new_sa, &old_sa))
  65      return (SLSig_Fun_Type *) SIG_ERR;
  66
  67    return old_sa.sa_handler;
  68 #else
  69    /* Not POSIX. */
  70    return signal (sig, f);
  71 #endif
  72 }
  73
  74 /* This function will NOT cause system calls to be restarted after
  75  * signal if possible
  76  */
  77 SLSig_Fun_Type *SLsignal_intr (int sig, SLSig_Fun_Type *f)
  78 {
  79 #ifdef SLANG_POSIX_SIGNALS
  80    struct sigaction old_sa, new_sa;
  81
  82    sigemptyset (&new_sa.sa_mask);
  83    new_sa.sa_handler = f;
  84
  85    new_sa.sa_flags = 0;
  86 # ifdef SA_INTERRUPT
  87    new_sa.sa_flags |= SA_INTERRUPT;
  88 # endif
  89
  90    if (-1 == sigaction (sig, &new_sa, &old_sa))
  91      return (SLSig_Fun_Type *) SIG_ERR;
  92
  93    return old_sa.sa_handler;
  94 #else
  95    /* Not POSIX. */
  96    return signal (sig, f);
  97 #endif
  98 }
  99
 100 /* We are primarily interested in blocking signals that would cause the
 101  * application to reset the tty.  These include suspend signals and
 102  * possibly interrupt signals.
 103  */
 104 #ifdef SLANG_POSIX_SIGNALS
 105 static sigset_t Old_Signal_Mask;
 106 #endif
 107
 108 static volatile unsigned int Blocked_Depth;
 109
 110 int SLsig_block_signals (void)
 111 {
 112 #ifdef SLANG_POSIX_SIGNALS
 113    sigset_t new_mask;
 114 #endif
 115
 116    Blocked_Depth++;
 117    if (Blocked_Depth != 1)
 118      {
 119         return 0;
 120      }
 121
 122 #ifdef SLANG_POSIX_SIGNALS
 123    sigemptyset (&new_mask);
 124 # ifdef SIGQUIT
 125    sigaddset (&new_mask, SIGQUIT);
 126 # endif
 127 # ifdef SIGTSTP
 128    sigaddset (&new_mask, SIGTSTP);
 129 # endif
 130 # ifdef SIGINT
 131    sigaddset (&new_mask, SIGINT);
 132 # endif
 133 # ifdef SIGTTIN
 134    sigaddset (&new_mask, SIGTTIN);
 135 # endif
 136 # ifdef SIGTTOU
 137    sigaddset (&new_mask, SIGTTOU);
 138 # endif
 139 # ifdef SIGWINCH
 140    sigaddset (&new_mask, SIGWINCH);
 141 # endif
 142
 143    (void) sigprocmask (SIG_BLOCK, &new_mask, &Old_Signal_Mask);
 144    return 0;
 145 #else
 146    /* Not implemented. */
 147    return -1;
 148 #endif
 149 }
 150
 151 int SLsig_unblock_signals (void)
 152 {
 153    if (Blocked_Depth == 0)
 154      return -1;
 155
 156    Blocked_Depth--;
 157
 158    if (Blocked_Depth != 0)
 159      return 0;
 160
 161 #ifdef SLANG_POSIX_SIGNALS
 162    (void) sigprocmask (SIG_SETMASK, &Old_Signal_Mask, NULL);
 163    return 0;
 164 #else
 165    return -1;
 166 #endif
 167 }
 168
 169 #ifdef MSWINDOWS
 170 int SLsystem (char *cmd)
 171 {
 172    SLang_verror (SL_NOT_IMPLEMENTED, "system not implemented");
 173    return -1;
 174 }
 175
 176 #else
 177 int SLsystem (char *cmd)
 178 {
 179 #ifdef SLANG_POSIX_SIGNALS
 180    pid_t pid;
 181    int status;
 182    struct sigaction ignore;
 183 # ifdef SIGINT
 184    struct sigaction save_intr;
 185 # endif
 186 # ifdef SIGQUIT
 187    struct sigaction save_quit;
 188 # endif
 189 # ifdef SIGCHLD
 190    sigset_t child_mask, save_mask;
 191 # endif
 192
 193    if (cmd == NULL) return 1;
 194
 195    ignore.sa_handler = SIG_IGN;
 196    sigemptyset (&ignore.sa_mask);
 197    ignore.sa_flags = 0;
 198
 199 # ifdef SIGINT
 200    if (-1 == sigaction (SIGINT, &ignore, &save_intr))
 201      return -1;
 202 # endif
 203
 204 # ifdef SIGQUIT
 205    if (-1 == sigaction (SIGQUIT, &ignore, &save_quit))
 206      {
 207         (void) sigaction (SIGINT, &save_intr, NULL);
 208         return -1;
 209      }
 210 # endif
 211
 212 # ifdef SIGCHLD
 213    sigemptyset (&child_mask);
 214    sigaddset (&child_mask, SIGCHLD);
 215    if (-1 == sigprocmask (SIG_BLOCK, &child_mask, &save_mask))
 216      {
 217 #  ifdef SIGINT
 218         (void) sigaction (SIGINT, &save_intr, NULL);
 219 #  endif
 220 #  ifdef SIGQUIT
 221         (void) sigaction (SIGQUIT, &save_quit, NULL);
 222 #  endif
 223         return -1;
 224      }
 225 # endif
 226
 227    pid = fork();
 228
 229    if (pid == -1)
 230      status = -1;
 231    else if (pid == 0)
 232      {
 233         /* Child */
 234 # ifdef SIGINT
 235         (void) sigaction (SIGINT, &save_intr, NULL);
 236 # endif
 237 # ifdef SIGQUIT
 238         (void) sigaction (SIGQUIT, &save_quit, NULL);
 239 # endif
 240 # ifdef SIGCHLD
 241         (void) sigprocmask (SIG_SETMASK, &save_mask, NULL);
 242 # endif
 243
 244         execl ("/bin/sh", "sh", "-c", cmd, NULL);
 245         _exit (127);
 246      }
 247    else
 248      {
 249         /* parent */
 250         while (-1 == waitpid (pid, &status, 0))
 251           {
 252 # ifdef EINTR
 253              if (errno == EINTR)
 254                continue;
 255 # endif
 256 # ifdef ERESTARTSYS
 257              if (errno == ERESTARTSYS)
 258                continue;
 259 # endif
 260              status = -1;
 261              break;
 262           }
 263      }
 264 # ifdef SIGINT
 265    if (-1 == sigaction (SIGINT, &save_intr, NULL))
 266      status = -1;
 267 # endif
 268 # ifdef SIGQUIT
 269    if (-1 == sigaction (SIGQUIT, &save_quit, NULL))
 270      status = -1;
 271 # endif
 272 # ifdef SIGCHLD
 273    if (-1 == sigprocmask (SIG_SETMASK, &save_mask, NULL))
 274      status = -1;
 275 # endif
 276
 277    return status;
 278
 279 #else                                  /* No POSIX Signals */
 280 # ifdef SIGINT
 281    void (*sint)(int);
 282 # endif
 283 # ifdef SIGQUIT
 284    void (*squit)(int);
 285 # endif
 286    int status;
 287
 288 # ifdef SIGQUIT
 289    squit = SLsignal (SIGQUIT, SIG_IGN);
 290 # endif
 291 # ifdef SIGINT
 292    sint = SLsignal (SIGINT, SIG_IGN);
 293 # endif
 294    status = system (cmd);
 295 # ifdef SIGINT
 296    SLsignal (SIGINT, sint);
 297 # endif
 298 # ifdef SIGQUIT
 299    SLsignal (SIGQUIT, squit);
 300 # endif
 301    return status;
 302 #endif                                 /* POSIX_SIGNALS */
 303 }
 304 #endif
 305
 306 #if 0
 307 #include <windows.h>
 308 static int msw_system (char *cmd)
 309 {
 310    STARTUPINFO startup_info;
 311    PROCESS_INFORMATION process_info;
 312    int status;
 313
 314    if (cmd == NULL) return -1;
 315
 316    memset ((char *) &startup_info, 0, sizeof (STARTUPINFO));
 317    startup_info.cb = sizeof(STARTUPINFO);
 318    startup_info.dwFlags = STARTF_USESHOWWINDOW;
 319    startup_info.wShowWindow = SW_SHOWDEFAULT;
 320
 321    if (FALSE == CreateProcess (NULL,
 322                                cmd,
 323                                NULL,
 324                                NULL,
 325                                FALSE,
 326                                NORMAL_PRIORITY_CLASS|CREATE_NEW_CONSOLE,
 327                                NULL,
 328                                NULL,
 329                                &startup_info,
 330                                &process_info))
 331      {
 332         SLang_verror (0, "%s: CreateProcess failed.", cmd);
 333         return -1;
 334      }
 335
 336    status = -1;
 337
 338    if (0xFFFFFFFFUL != WaitForSingleObject (process_info.hProcess, INFINITE))
 339      {
 340         DWORD exit_code;
 341
 342         if (TRUE == GetExitCodeProcess (process_info.hProcess, &exit_code))
 343           status = (int) exit_code;
 344      }
 345
 346    CloseHandle (process_info.hThread);
 347    CloseHandle (process_info.hProcess);
 348
 349    return status;
 350 }
 351 #endif